Module 05: Diseases and Disorders


This Module contains 6 lessons covering:
  • Lesson 1: Epidemiology and Public Health
  • Lesson 2: Noncommunicable Diseases and Disorders
  • Lesson 3: Cardiovascular Diseases
  • Lesson 4: Cancer
  • Lesson 5: Communicable (Infectious) Diseases
  • Lesson 6: Immunity and Immunizations


Students will be able to:
  • examine and discuss the role of epidemiology in public health
  • recognize, examine and formulate the importance of immunization
  • identify the major means of transmission for communicable diseases
  • identify and examine immunizations in relationship to immunity
  • differentiate the major classifications of communicable and non-communicable diseases

Lesson 1: Introduction to Epidemiology


Source: Centers for Disease Control, EXCITE,

This background lesson provides several working definitions of epidemiology—the basic science of public health; an introduction to the different categories of epidemiology and types of epidemiological studies; and an overview of the disease transmission cycle. First, to set the stage, consider the three incidents that follow, stepping into the shoes of the public health officer who received the initial report and asking yourself the question, "What do I do now?" Some of these examples made national news and may be familiar to you.

First Incident

In March 1985, a nurse epidemiologist in a county health department noted, while reviewing surveillance data, three cases in a single month of hepatitis B of unusual origin. Hepatitis B, or serum hepatitis, is transmitted through sexual contact and by exposure to infected bodily fluids, but these three patients did not seem to have the usual risk factors. All three people did, however, indicate having received injections at the same health care facility.
The nurse's immediate questions were:

Is this a coincidence? Did these three cases occur by chance or is there a link? In this instance, the nurse decided to pursue an investigation.

Second Incident

At 8:30 in the morning on August 2, 1976, Dr. Robert B. Craven of Centers for Disease Control’s (CDC) Viral Diseases Division received a call from a nurse at a Veterans' Hospital in Philadelphia, Pennsylvania. The nurse reported two cases of severe respiratory illness, one of which had been fatal. Both people had attended the annual American Legion Convention held July 21-24. By the evening of August 2, 71 more of the people attending the convention had the same illness, with symptoms of acute onset of fever, chills, headache, malaise, dry cough, and myalgia. Further conversations with local and state public health officials revealed that between July 26 and August 2, 18 conventioneers had died. Deaths were due primarily to pneumonia.
An intense investigation began immediately. The incident became known as the first outbreak of Legionnaires' disease and led to the discovery of the gram-negative pathogen, Legionnella pneumophila.

Third Incident

On October 30, 1989, a New Mexico physician notified the state's health department of three patients with marked peripheral eosinophilia and severe myalgia. All three patients had been taking oral preparations of L-tryptophan, a nonprescription drug sold as a dietary supplement in health food stores. Despite extensive clinical evaluation and testing, the illness could not be identified.
An investigation followed and resulted in the characterization of eosinophilia-myalgia syndrome, EMS. The investigation implicated a vehicle for exposure—L-tryptophan dietary supplements—before a suspected agent was identified, and the product was taken off the market. Eventually, the problem was traced to a contaminant that had been introduced by changes in the production process at a single manufacturing facility.
These three examples illustrate some of the key reasons for needing applied, or field, epidemiology:
  • They were unexpected.
  • They demanded a response.
  • The investigators had to go out into the field to solve the problem.

Epidemiology Defined

A definition of epidemiology is "the study of the distribution and determinants of health-related states in specified populations, and the application of this study to control health problems." A look at the key words will help illuminate the meaning:
  • Epidemiology is the basic science of public health. It's a highly quantitative discipline based on principles of statistics and research methodologies.
  • Distribution Epidemiologists study the distribution of frequencies and patterns of health events within groups in a population. To do this, they use descriptive epidemiology, which characterizes health events in terms of time, place, and person
  • Determinant Epidemiologists also attempt to search for causes or factors that are associated with increased risk or probability of disease. This type of epidemiology, where we move from questions of "who," "what," "where," and "when" and start trying to answer "how" and "why," is referred to as analytical epidemiology
A comparison between the practice of public health and the more familiar practice of health care helps in describing epidemiology. First, where health care practitioners collect data on an individual patient by taking a medical history and conducting a physical exam, epidemiologists collect data about an entire population through surveillance systems or descriptive epidemiological studies. The health care practitioner uses his or her data to make a differential diagnosis. The epidemiologist's data is used to generate hypotheses about the relationships between exposure and disease. Both disciplines then test the hypotheses, the health care practitioner by conducting additional diagnostic studies or tests, the epidemiologist by conducting analytical studies such as cohort or case-control studies. The final step is to take action. The health care practitioner prescribes medical treatment, and the epidemiologist, some form of community intervention to end the health problem and prevent its recurrence.
Health Care Professional
Collects data on an individual patient by taking a medical history and conducting a physical exam
Collects data about an entire population through surveillance systems or descriptive epidemiological studies
Uses his or her data to make a differential diagnosis
Data is used to generate hypotheses about the relationships between exposure and disease
Tests the hypothesis by conducting additional diagnostic studies or tests
Tests the hypothesis by conducting analytical studies such as cohort or case-control studies
Prescribes medical treatment
Develops community intervention to end the health problem and prevent its recurrence

One way to sum up the task of epidemiologists is to say that they "count things." Basically, epidemiologists count cases of disease or injury, define the affected population, and then compute rates of disease or injury in that population. Then they compare these rates with those found in other populations and make inferences regarding the patterns of disease to determine whether a problem exists.

For example, in the hepatitis B example earlier, you might ask: Is the rate of disease among people with no know risk factors greater than we would expect? Is the pattern or distribution of the cases suspicious? Once a problem has been identified, the data are used to determine the cause of the health problem; the modes of transmission; any factors that are related to susceptibility, exposure, or risk; and any potential environmental determinants.

Epidemiological Studies

As mentioned earlier, epidemiologists used several different types of studies. Simply speaking, these can be classified as either experimental, where the epidemiologists have control over the circumstances from the start, or observational, where they do not. Vaccine efficacy trials are a good example of experimental studies because investigators control who gets the vaccine and who doesn't. Observational studies can be further subdivided into descriptive and analytical studies. In a descriptive study, the epidemiologist collects information to characterize and summarize the health event or problem. In an analytical study, the epidemiologist relies on comparisons between groups to determine the role of various risk factors in causing the problem. Descriptive epidemiology is the most basic of these categories and is fundamental to the work of an epidemiologists.
Another way of comparing descriptive and analytical epidemiology is to say that in the descriptive process, we are concerned with "person" (Who was affected?), "place" (Where were they affected?), and time (When were they affected?). Once we know the answers to these questions, we can enter the realm of analytical epidemiology and ask how and why these people were affected.

Disease Transmission

In talking about epidemiology, it is important to review how outbreaks occur. First, we'll look at three commonly used, and often misunderstood, terms: "epidemic," "outbreak," and "cluster." An epidemic is the occurrence of more cases of disease than would normally be expected in a specific place or group of people over a given period of time. To an epidemiologist, "outbreak" means basically the same thing. In the public's mind, however, "epidemic" has a far more serious connotation than "outbreak." For this reason, "outbreak" is often used to avoid sensationalism. The third term, "cluster," is occasionally used, incorrectly, in place of "epidemic" or "outbreak." A cluster is a group of cases in a specific time and place that may or may not be greater than the expected rate. Often the aim of investigating clusters is to determine the baseline rate of disease for that time and place. Two other terms you will come across are "endemic," meaning a high background rate of disease, and "pandemic," meaning very widespread, often global, disease.

Learning Activity 1.1:
Watch this TED-Ed video: How Pandemics Spread
  • Take the Quick Quiz.
  • Think: Why are epidemics and pandemics a relatively recent phenomenon in human history?

For an outbreak, or epidemic, to occur, the basic elements of disease causation and an adequate chain of transmission must be present. Disease occurs when an outside agent capable of causing the disease meets a host that is vulnerable to the agent in an environment that allows the agent and host to interact. Then, given a chain of transmission from one host to another and a suitable mode of spread, an outbreak can develop. These basic concepts help guide the selection of public health strategies to prevent health problems. Depending on which approach might be most effective, we might direct efforts at the specific agent (e.g., guinea worm), host (e.g., immunization to prevent measles), or environment (e.g., sanitation improvements to prevent salmonella). We can also target a specific point in the chain of transmission. This was the response in the E.coli outbreak in Washington State in the early 1990s, when health officials called for the thorough cooking of hamburgers to interrupt transmission of the bacterium.

The host is the person, or in a more generic definition, the organism, that is susceptible to the effect of the agent. The status of the host is quite important and is generally classifiable as susceptible, immune, or infected. Finally, and also quite important, is that the host's response to exposure can vary widely, from showing no effect to manifesting illness.

The environment is the conditions or influences that are not part of either the agent or the host, but that influence their interaction. A wide variety of factors, including physical, climatologic, biologic, social, and economic conditions, can come into play. For instance, in a study of motor vehicle injuries, the agent (mechanical energy) and the host (driver) could be affected by the topography, the weather, and the actions of other drivers. In many infectious disease outbreaks, social and economic conditions cause overcrowding and lead to high levels of exposure.

Agent, host, and environment alone are not sufficient to cause an epidemic; an adequate chain of transmission must be present. This process requires a source for the agent, a portal of exit, a mode of transmission, and a portal of entry. The first element, the source for the agent, is often the place where the agent originates, where it lives, grows, and multiplies, but this is not always the case. The agent that causes botulism (Clostridium botulinum), for example, originates in soil, but the source of most botulism infections is improperly canned food containing C. botulinum spores.

The second element, a portal of exit, is a pathway by which the agent can leave the source. This pathway is usually related to the place where the agent is localized. For instance, the agents causing tuberculosis and the flu are released through the respiratory tract, whereas agents for many stomach ailments are released through the digestive tract. Agents found in the blood, such as hepatitis B and HIV, can be released through cuts or needles.
Once the agent leaves the source, a mode of transmission, or means of carrying it to the host, is needed. This can happen in a number of ways, some of which are direct and some indirect. Direct transmission includes contact with soil or plants as well as contact between people. In indirect transmission, the agent can be airborne, vector borne, or vehicle borne. In airborne transmission, the agent is carried from the source to the host suspended in air particles. Vector-borne diseases are transmitted indirectly by a live carrier, usually an arthropod, such as mosquitos, fleas, or ticks. Vehicle-borne diseases are carried by inanimate objects, such as food or water, blood, or items like handkerchiefs, bedding, and surgical instruments.

Finally, there must be a pathway into the host, a portal of entry, that gives the agent access to tissue where it can multiply or act. Often the agent enters the host in the same way that it left the source. This is the case with the flu virus, which leaves the source through the respiratory tract and enters a new host through the respiratory tract.

Learning Activity 1.2: Your Disease Risk
Here, you can find out your risk of developing five of the most important diseases in the United States and get personalized tips for preventing them.

The Chain of Infection Model

Source: Health Education, Advocacy and Community Mobilization Module, CC-BY-NC-SA,

This model explains the spread of a communicable disease from one host (or person) to another. The basic idea represented in the chain of infection is that individuals can break the chain (reduce the risk) at any point, thus the spread of the disease can be stopped.

Table 3.1 Chain of infection.

Component of the model


Preventive measures

Communicable disease
Disease caused by an infectious agent
Pasteurization, chlorination, antibiotics, disinfectants, hand washing, etc.
Human reservoir
The human being who is harboring the infectious agent
Isolation, surveillance, treatment with medications, etc.
Portal of exit
The body part through which the infectious agent is exiting from the reservoir, for example the mouth or the anus
Utilization of handkerchiefs, condoms, hair nets, insect repellents, hand washing, etc.
The spread of the infectious agent from the reservoir to the host
Isolation, hand washing, mosquito control, sexual abstinence, condom users, etc.
Portal of entry
The body part through which the infectious agent will enter the new host, for example the skin after a mosquito bite, the mouth
Condoms, hair nets, insect repellents, hand washing, etc.
Establishment of disease in new host (susceptible person)
The host develops signs and symptoms of the new disease
Immunizations, health education, nutrition promotion; sexual abstinence, condom use, etc.
Now look at Table 3.1 carefully again.

There are two sets of components that have some similar preventive measures. As a way of helping yourself become familiar with this chart see if you can spot which these are.
The portal of entry and exit both involve preventive measures such as hand washing, condoms, hair nets and insect repellents, while the human reservoir and transmission measures both involve isolation. Be sure you have a clear picture of the definition and prevention of each element before you continue.
With the application of such information, health education can help to create programs that are aimed at breaking the chain and reducing the risks of infection in other people.

The communicable disease model

  • The communicable disease model presents three elements; infectious agent, host and environment, as the minimal requirements for the presence and spread of a communicable disease in a population.
  • The infectious agent is the element that must be present for the disease to occur and spread. Bacteria, viruses and parasites are examples of infectious agents.
  • The host is any susceptible organism. Plants, animals or humans can be invaded by the infectious agent and become the host.
  • The environment includes all other factors that either promote or prohibit disease transmission.

Communicable disease transmission occurs when a susceptible host and an infectious agent exist in an environment that allows disease transmission.
According to the communicable disease model, the role of health education and health promotion in reducing the occurrence and transmission of diseases can be brought about by specific actions.
Think of tuberculosis (TB), malaria and intestinal infections as examples, and then answer the following questions:
  1. Note one way to reduce the susceptibility of hosts.
  2. Note one way to destroy infectious agents.
  3. Note one way to reduce the contact between the host and the agent.
  4. Note one way to modify the environment so that it is not conducive for disease transmission.
You may have answered with the following examples:
  1. Good nutrition will build a person’s defenses against infection and reduce their risk of developing TB.
  2. Cooking food properly destroys infectious agents that could cause intestinal infections.
  3. Wearing a mask or holding your hand in front of your mouth while coughing will reduce the contact between the agent that causes TB, and other human beings.
  4. Drying swampy and marshy areas will make the environment less easy for mosquitoes to breed in and therefore reduce the incidence of malaria.

Health risk reduction for non-communicable diseases

Both the chain of infection and communicable disease models are helpful in trying to prevent disease caused by an infectious agent. However, these models are not applicable to non-communicable diseases, which include many of the chronic diseases such as heart disease and cancers. Most of these diseases become apparent in people over a period of time and are not caused by a single factor, but by a combination of factors. The concept of ‘caused by many factors’ is often called the multi causation disease model. For example, it is known that heart disease is most likely to be a problem for individuals who are older, who smoke, who do not exercise, who are overweight, who have high blood pressure, who have high blood cholesterol and who have a family history of heart disease.

Note that within the list of factors you have just read there are both modifiable and non-modifiable risk factors.

Look at the list again and put an "M" against the modifiable factors and an "NM" against the non-modifiable factors.
  • Are older: _
  • Smoke: _
  • Do not exercise: _
  • Are overweight: _
  • Have high blood pressure: _
  • Have high cholesterol: _
  • Have a family history of heart disease: _

According to this model, health education will be useful in risk reduction and disease prevention if you can create programs that help people control as many of the multi causative risk factors as possible.

  • Are older: NM
  • Smoke: M
  • Do not exercise: M
  • Are overweight: M
  • Have high blood pressure: M
  • Have high cholesterol: M
  • Have a family history of heart disease: NM

Learning Activity 4.3:

Go to the Cost of Getting Sick webpage then click on the different color pies in the circle to find out the healthcare costs associated with various chronic health conditions.

Learning Activity 4.4: Leading Causes of Death

Lesson 2: Noncommunicable Diseases and Disorders

Noncommunicable Diseases and Disorders

Diseases are classified as either communicable or noncommunicable. Communicable diseases are spread to other people and they are caused by viral, bacterial, parasitic, or fungal infection. Noncommunicable diseases, also known as non- infectious diseases, are not transferred and are typically caused by heredity, deficiencies in nutrition or factors involving the environment. Some noncommunicable diseases include –

  • Respiratory disorders
  • Diabetes
  • Headaches
  • Arthritis
  • Skin disorders
  • Neurological disorders
  • Cancer
  • Cardiovascular Diseases and Disorders

Respiratory Disorders

Chronic Obstructive Pulmonary Disease

  • COPD, or chronic obstructive pulmonary (PULL-mun-ary) disease, is a progressive disease that makes it hard to breathe. "Progressive" means the disease gets worse over time.
  • COPD can cause coughing that produces large amounts of mucus (a slimy substance), wheezing, shortness of breath, chest tightness, and other symptoms.
  • Cigarette smoking is the leading cause of COPD. Most people who have COPD smoke or used to smoke. Long-term exposure to other lung irritants, such as air pollution, chemical fumes, or dust, also may contribute to COPD.
  • COPD, or chronic obstructive pulmonary disease, is a major cause of disability and the third leading cause of death in the United States. More than 12 million people are currently diagnosed with COPD. An additional 12 million likely have the disease and don't even know it.

Learning Activity 2.1: Watch this video titled COPD Learn More Breathe Better by clicking on Windows media or Quicktime below.

Profiling the personal experiences of three people diagnosed with COPD, this video answers basic questions about the disease and its risk factors, and demonstrates how real people took steps to manage the disease and breathe easier.

  • Could you identify with any of the people in this video?
  • What seems to be most helpful to these folks when it comes to managing their COPD?
  • What did you learn that you didn't already know before watching this video?


To understand COPD, it helps to understand how the lungs work. The air that you breathe goes down your windpipe into tubes in your lungs called bronchial tubes or airways.
The airways and air sacs are elastic (stretchy). When you breathe in, each air sac fills up with air like a small balloon. When you breathe out, the air sacs deflate and the air goes out.
In COPD, less air flows in and out of the airways because of one or more of the following:
  • The airways and air sacs lose their elastic quality.
  • The walls between many of the air sacs are destroyed.
  • The walls of the airways become thick and inflamed.
  • The airways make more mucus than usual, which tends to clog them.

In the United States, the term "COPD" includes two main conditions—emphysema (em-fi-SE-ma) and chronic bronchitis (bron-KI-tis).

In emphysema, the walls between many of the air sacs are damaged, causing them to lose their shape and become floppy. This damage also can destroy the walls of the air sacs, leading to fewer and larger air sacs instead of many tiny ones. If this happens, the amount of gas exchange in the lungs is reduced.

In chronic bronchitis, the lining of the airways is constantly irritated and inflamed. This causes the lining to thicken. Lots of thick mucus forms in the airways, making it hard to breathe. Most people who have COPD have both emphysema and chronic obstructive bronchitis. Thus, the general term "COPD" is more accurate.


  • COPD is a major cause of disability, and it's the third leading cause of death in the United States. More than 12 million people are currently diagnosed with COPD. Many more people may have the disease and not even know it.
  • COPD develops slowly. Symptoms often worsen over time and can limit your ability to do routine activities. Severe COPD may prevent you from doing even basic activities like walking, cooking, or taking care of yourself.
  • Most of the time, COPD is diagnosed in middle-aged or older people. The disease isn't passed from person to person—you can't catch it from someone else.
  • COPD has no cure yet, and doctors don't know how to reverse the damage to the airways and lungs. However, treatments and lifestyle changes can help you feel better, stay more active, and slow the progress of the disease.

How Can COPD Be Prevented?

You can take steps to prevent COPD before it starts. If you already have COPD, you can take steps to prevent complications and slow the progress of the disease.

Prevent COPD Before It Starts

The best way to prevent COPD is to not start smoking or to quit smoking. Smoking is the leading cause of COPD.

Learning Activity 2.2: Take an ungraded quiz about COPD.

Test your knowledge about the causes and symptoms of COPD. Learn how the disease affects the lungs and how you can prevent its complications.

Chronic Bronchitis

Source: NIH, National Heart, Lung, and Blood Institute via

Bronchitis is an inflammation of the bronchial tubes, the airways that carry air to your lungs. It causes a cough that often brings up mucus, as well as shortness of breath, wheezing, and chest tightness. There are two main types of bronchitis: acute and chronic.
Chronic bronchitis is one type of COPD (chronic obstructive pulmonary disease). The inflamed bronchi produce a lot of mucus. This leads to cough and difficulty getting air in and out of the lungs. Cigarette smoking is the most common cause. Breathing in other fumes and dusts over a long period of time may also cause chronic bronchitis. Treatment will help your symptoms, but chronic bronchitis is a long-term condition that keeps coming back or never goes away completely.


Source: NIH, National Heart, Lung, and Blood Institute via

Emphysema is a type of chronic obstructive pulmonary disease (COPD) involving damage to the air sacs (alveoli) in the lungs. As a result, your body does not get the oxygen it needs. Emphysema makes it hard to catch your breath. You may also have a chronic cough and have trouble breathing during exercise.
The most common cause is cigarette smoking. If you smoke, quitting can help prevent you from getting the disease. If you already have emphysema, not smoking might keep it from getting worse. Treatment is based on whether your symptoms are mild, moderate or severe. Treatments include inhalers, oxygen, medications and sometimes surgery to relieve symptoms and prevent complications.


Asthma is a chronic lung disease that inflames and narrows the airways, making it hard to breathe. The disease affects people of all ages, but it most often starts in childhood. People who have asthma may wheeze, cough, feel short of breath, or have chest tightness.

Asthma can't be cured, but it can be controlled. People who have asthma, or those who have children with asthma, can take an active role in their treatment. For example, they can work with their health care providers to create an asthma action plan. This plan gives guidance on taking medicines properly, avoiding asthma triggers, tracking levels of asthma control, responding to worsening symptoms, and seeking emergency care when needed. When asthma is well controlled, most people who have the disease are able to live normal, active lives.
For more information about living with and managing asthma, go to the Health Topics Asthma article.

Learning Activity 2.3: Watch this video titled Living With and Managing Asthma.
This video—presented by the National Heart, Lung, and Blood Institute, part of the National Institutes of Health—describes asthma, its signs and symptoms, and ways to manage the disease.


Source: NIH: National Institute of Diabetes and Digestive and Kidney Diseases via MedlinePlus

Diabetes is a disease in which your blood glucose, or sugar, levels are too high. Glucose comes from the foods you eat. Insulin is a hormone that helps the glucose get into your cells to give them energy. With Type 1 diabetes, your body does not make insulin. With Type 2 diabetes, the more common type, your body does not make or use insulin well. Without enough insulin, the glucose stays in your blood.
Over time, having too much glucose in your blood can cause serious problems. It can damage your eyes, kidneys, and nerves. Diabetes can also cause heart disease, stroke and even the need to remove a limb. Pregnant women can also get diabetes, called gestational diabetes.
A blood test can show if you have diabetes. Exercise, weight control and sticking to your meal plan can help control your diabetes. You should also monitor your glucose level and take medicine if prescribed.
Diabetes means your blood glucose, or blood sugar, is too high. With Type 1 diabetes, your pancreas does not make insulin. Insulin is a hormone that helps glucose get into your cells to give them energy. Without insulin, too much glucose stays in your blood. Over time, high blood glucose can lead to serious problems with your heart, eyes, kidneys, nerves, and gums and teeth.
Type 1 diabetes happens most often in children and young adults but can appear at any age. Symptoms may include
  • Being very thirsty
  • Urinating often
  • Feeling very hungry or tired
  • Losing weight without trying
  • Having sores that heal slowly
  • Having dry, itchy skin
  • Losing the feeling in your feet or having tingling in your feet
  • Having blurry eyesight
A blood test can show if you have diabetes. If you do, you will need to take insulin for the rest of your life.
Diabetes means your blood glucose, or blood sugar, is too high. With Type 2 diabetes, the more common type, your body does not make or use insulin well. Insulin is a hormone that helps glucose get into your cells to give them energy. Without insulin, too much glucose stays in your blood. Over time, high blood glucose can lead to serious problems with your heart, eyes, kidneys, nerves, gums and teeth.
You have a higher risk of type 2 diabetes if you are older, obese, have a family history of diabetes, or do not exercise.
The symptoms of type 2 diabetes appear slowly. Some people do not notice symptoms at all. The symptoms can include
  • Being very thirsty
  • Urinating often
  • Feeling very hungry or tired
  • Losing weight without trying
  • Having sores that heal slowly
  • Having blurry eyesight
A blood test can show if you have diabetes. Many people can manage their diabetes through healthy eating, physical activity, and blood glucose testing. Some people also need to take diabetes medicines.

What are the most important things to do to prevent diabetes?

Source: Prevent Diabetes, Centers for Disease Control,

The Diabetes Prevention Program (DPP), a major federally funded study of 3,234 people at high risk for diabetes, showed that people can delay and possibly prevent the disease by losing a small amount of weight (5 to 7 percent of total body weight) through 30 minutes of physical activity 5 days a week and healthier eating.

What are the risk factors which increase the likelihood of developing diabetes?

  • Being overweight or obese.
  • Having a parent, brother, or sister with diabetes.
  • Being African American, American Indian, Asian American, Pacific Islander, or Hispanic American/Latino heritage.
  • Having a prior history of gestational diabetes or birth of at least one baby weighing more than 9 pounds.
  • Having high blood pressure measuring 140/90 or higher.
  • Having abnormal cholesterol with HDL ("good") cholesterol is 35 or lower, or triglyceride level is 250 or higher.
  • Being physically inactive—exercising fewer than three times a week.

How does body weight affect the likelihood of developing diabetes?

Being overweight or obese is a leading risk factor for type 2 diabetes. Being overweight can keep your body from making and using insulin properly, and can also cause high blood pressure. The Diabetes Prevention Program (DPP), a major federally funded study of 3,234 people at high risk for diabetes, showed that moderate diet and exercise of about 30 minutes or more, 5 or more days per week, or of 150 or more minutes per week, resulting in a 5% to 7% weight loss can delay and possibly prevent type 2 diabetes.


Source: NIH: National Institute of Neurological Disorders and Stroke via

Oh my aching head! Nearly everyone has had a headache. The most common type of headache is a tension headache. Tension headaches are due to tight muscles in your shoulders, neck, scalp and jaw. They are often related to stress, depression or anxiety. You are more likely to get tension headaches if you work too much, don't get enough sleep, miss meals or use alcohol.
ther common types of headaches include migraines, cluster headaches and sinus headaches. Most people can feel much better by making lifestyle changes, learning ways to relax and taking pain relievers.

Headaches can have many causes, but serious causes of headaches are rare. Sometimes headaches warn of a more serious disorder. Let your health care provider know if you have sudden, severe headaches. Get medical help right away if you have a headache after a blow to your head, or if you have a headache along with a stiff neck, fever, confusion, loss of consciousness or pain in the eye or ear.

A migraine is a very painful type of headache. People who get migraines often describe the pain as pulsing or throbbing in one area of the head. During migraines, people are very sensitive to light and sound. They may also become nauseated and vomit.

Migraine is three times more common in women than in men. Some people can tell when they are about to have a migraine because they see flashing lights or zigzag lines or they temporarily lose their vision.

Many things can trigger a migraine. These include
  • Stress
  • Lack of food or sleep
  • Exposure to light
  • Hormonal changes (in women)
Doctors used to believe migraines were linked to the opening and narrowing of blood vessels in the head. Now they believe the cause is related to genes that control the activity of some brain cells. Medicines can help prevent migraine attacks or help relieve symptoms of attacks when they happen. For many people, treatments to relieve stress can also help.


Source: NIH: National Institute of Arthritis and Musculoskeletal and Skin Diseases via

If you feel pain and stiffness in your body or have trouble moving around, you might have arthritis. Most kinds of arthritis cause pain and swelling in your joints. Joints are places where two bones meet, such as your elbow or knee. Over time, a swollen joint can become severely damaged. Some kinds of arthritis can also cause problems in your organs, such as your eyes or skin.
One type of arthritis, osteoarthritis, is often related to aging or to an injury. Other types occur when your immune system, which normally protects your body from infection, attacks your body's own tissues. Rheumatoid arthritis is the most common form of this kind of arthritis. Juvenile rheumatoid arthritis is a form of the disease that happens in children. Infectious arthritis is an infection that has spread from another part of the body to the joint.
Osteoarthritis is the most common form of arthritis. It causes pain, swelling and reduced motion in your joints. It can occur in any joint, but usually it affects your hands, knees, hips or spine.
Osteoarthritis breaks down the cartilage in your joints. Cartilage is the slippery tissue that covers the ends of bones in a joint. Healthy cartilage absorbs the shock of movement. When you lose cartilage, your bones rub together. Over time, this rubbing can permanently damage the joint. Factors that may cause osteoarthritis include
  • Being overweight
  • Getting older
  • Injuring a joint
Therapies that manage osteoarthritis pain and improve function include exercise, weight control, rest, pain relief, alternative therapies and surgery.

Skin Disorders

Source: Skin Disorders, National Institute of Arthritis and Musculoskeletal and Skin Disease, NIH,

Did you know that your skin is the largest organ of your body? It is, in terms of both weight, between 6 and 9 pounds, and surface area, about 2 square yards. Your skin separates the inside of your body from the outside world. Skin:
  • Protects you from bacteria and viruses that can cause infections
  • Helps you sense the outside world, such as whether it is hot or cold, wet or dry
  • Regulates your body temperature
Conditions that irritate, clog or inflame your skin can cause symptoms such as redness, swelling, burning and itching. Allergies, irritants, your genetic makeup and certain diseases and immune system problems can cause dermatitis, hives and other skin conditions. Many skin problems, such as acne, also affect your appearance.


A rash is an area of irritated or swollen skin. It might be red and itchy, bumpy, scaly, crusty or blistered. Rashes are a symptom of many different medical conditions. Things that can cause a rash include other diseases, irritating substances, allergies and your genetic makeup.
Contact dermatitis is a common cause of rashes. It causes redness, itching and burning where you have touched an irritant, such as a chemical, or something you are allergic to, like poison ivy.
Some rashes develop immediately. Others form over several days. If you scratch your rash, it might take longer to heal. The treatment for a rash usually depends on its cause. Options include moisturizers, lotions, baths, cortisone creams that relieve swelling, and antihistamines, which relieve itching.


Hives are red and sometimes itchy bumps on your skin. An allergic reaction to a drug or food usually causes them. Allergic reactions cause your body to release chemicals that can make your skin swell up in hives. People who have other allergies are more likely to get hives than other people. Other causes include infections and stress.
Hives are very common. They usually go away on their own, but if you have a serious case, you might need medicine or a shot. In rare cases, allergic reactions can cause a dangerous swelling in your airways, making it hard to breathe - which is a medical emergency.


Acne is a common skin disease that causes pimples. Pimples form when hair follicles under your skin clog up. Most pimples form on the face, neck, back, chest and shoulders. Anyone can get acne, but it is common in teenagers and young adults. It is not serious, but it can cause scars.
No one knows exactly what causes acne. Hormone changes, such as those during the teenage years and pregnancy, probably play a role. There are many myths about what causes acne. Chocolate and greasy foods are often blamed, but there is little evidence that foods have much effect on acne in most people. Another common myth is that dirty skin causes acne; however, blackheads and pimples are not caused by dirt. Stress doesn't cause acne, but stress can make it worse.
If you have acne
  • Clean your skin gently
  • Try not to touch your skin
  • Avoid the sun
Treatments for acne include medicines and creams.


Scabies is an itchy skin condition caused by the microscopic mite Sarcoptes scabei. It is common all over the world, and it affects people of all races and social classes. Scabies spreads quickly in crowded conditions where there is frequent skin-to-skin contact between people. Hospitals, child-care centers and nursing homes are examples. Scabies can easily infect sex partners and other household members. Sharing clothes, towels, and bedding can also spread scabies. You cannot get scabies from a pet. Pets get a different mite infection called mange.
Symptoms are
  • Pimple-like irritations or a rash
  • Intense itching, especially at night
  • Sores caused by scratching
Several lotions are available to treat scabies. The infected person's clothes, bedding and towels should be washed in hot water and dried in a hot dryer.


Psoriasis is a skin disease that causes itchy or sore patches of thick, red skin with silvery scales. You usually get them on your elbows, knees, scalp, back, face, palms and feet, but they can show up on other parts of your body. A problem with your immune system causes psoriasis. In a process called cell turnover, skin cells that grow deep in your skin rise to the surface. Normally, this takes a month. In psoriasis, it happens in just days because your cells rise too fast.
Psoriasis can last a long time, even a lifetime. Symptoms come and go. Things that make them worse include
  • Infections
  • Stress
  • Dry skin
  • Certain medicines
Psoriasis usually occurs in adults. It sometimes runs in families. Treatments include creams, medications and light therapy.

Neurological Disorders

Source: Neurological Disorders, NLM, NIH,

Neurological disorders include:
  • Diseases caused by faulty genes, such as Huntington's disease and muscular dystrophy
  • Problems with the way the nervous system develops, such as spina bifida
  • Degenerative diseases, where nerve cells are damaged or die, such as Parkinson's disease and Alzheimer's disease
  • Injuries to the spinal cord and brain
  • Seizure disorders, such as epilepsy
  • Cancer, such as brain tumors
  • Meningitis

Huntington's Disease

Source: Huntington's Disease, NIH, National Institute of Neurological Disorders and Stroke,

Huntington's disease (HD) is an inherited disease that causes certain nerve cells in the brain to waste away. People are born with the defective gene, but symptoms usually don't appear until middle age. Early symptoms of HD may include uncontrolled movements, clumsiness or balance problems. Later, HD can take away the ability to walk, talk or swallow. Some people stop recognizing family members. Others are aware of their environment and are able to express emotions. If one of your parents has Huntington's disease, you have a 50-50 chance of getting it. A blood test can tell if you have the HD gene and will develop the disease. Genetic counseling can help you weigh the risks and benefits of taking the test. There is no cure. Medicines can help manage some of the symptoms, but cannot slow down or stop the disease.

Muscular Dystrophy

Source: NIH: National Institute of Neurological Disorders and Stroke via

Muscular dystrophy (MD) refers to a group of more than 30 inherited diseases that cause muscle weakness and muscle loss. Some forms of MD appear in infancy or childhood, while others may not appear until middle age or later. The different muscular dystrophies vary in who they affect and the symptoms. All forms of MD grow worse as the person's muscles get weaker. Most people with MD eventually lose the ability to walk.
There is no cure for muscular dystrophy. Treatments include physical and speech therapy, orthopedic devices, surgery and medications. Some people with muscular dystrophy have mild cases that worsen slowly. Other cases are disabling and severe.

Spina Bifida

Source: NIH: National Institute of Neurological Disorders and Stroke via

Spina bifida is the most common disabling birth defect in the United States. It is a type of neural tube defect, which is a problem with the spinal cord or its coverings. It happens if the fetal spinal column doesn't close completely during the first month of pregnancy. There is usually nerve damage that causes at least some paralysis of the legs. Many people with spina bifida will need assistive devices such as braces, crutches or wheelchairs. They may have learning difficulties, urinary and bowel problems or hydrocephalus, a buildup of fluid in the brain.
There is no cure. Treatments focus on the complications, and can include surgery, medicine and physiotherapy. Taking folic acid can reduce the risk of having a baby with spina bifida. It's in most multivitamins. Women who could become pregnant should take it daily.

Parkinson’s Disease


Parkinson's disease is a disorder that affects nerve cells, or neurons, in a part of the brain that controls muscle movement. In Parkinson's, neurons that make a chemical called dopamine die or do not work properly. Dopamine normally sends signals that help coordinate your movements. No one knows what damages these cells. Symptoms of Parkinson's disease may include
  • Trembling of hands, arms, legs, jaw and face
  • Stiffness of the arms, legs and trunk
  • Slowness of movement
  • Poor balance and coordination
As symptoms get worse, people with the disease may have trouble walking, talking or doing simple tasks. They may also have problems such as depression, sleep problems or trouble chewing, swallowing or speaking.
Parkinson's usually begins around age 60, but it can start earlier. It is more common in men than in women. There is no cure for Parkinson's disease. A variety of medicines sometimes help symptoms dramatically.

Alzheimer's Disease

Alzheimer's disease (AD) is the most common form of dementia among older people. Dementia is a brain disorder that seriously affects a person's ability to carry out daily activities.
AD begins slowly. It first involves the parts of the brain that control thought, memory and language. People with AD may have trouble remembering things that happened recently or names of people they know. A related problem, mild cognitive impairment(MCI), causes more memory problems than normal for people of the same age. Many, but not all, people with MCI will develop AD.
In AD, over time, symptoms get worse. People may not recognize family members or have trouble speaking, reading or writing. They may forget how to brush their teeth or comb their hair. Later on, they may become anxious or aggressive, or wander away from home. Eventually, they need total care. This can cause great stress for family members who must care for them.
AD usually begins after age 60. The risk goes up as you get older. Your risk is also higher if a family member has had the disease.
No treatment can stop the disease. However, some drugs may help keep symptoms from getting worse for a limited time.

Spinal Cord Injury


Your spinal cord is the part of your nervous system that relays messages to and from your brain. It is housed inside your vertebrae, which are the bone disks that make up your spine. Normally, your vertebrae protect your spinal cord. If they don't, you can sustain a spinal cord injury. Besides injuries, the spinal cord can develop
  • Tumors
  • Infections such as meningitis and poliomyelitis
  • Inflammatory diseases
  • Autoimmune diseases
  • Degenerative diseases such as amyotrophic lateral sclerosis and spinal muscular atrophy
Symptoms vary but might include pain, numbness, loss of sensation and muscle weakness. These symptoms can occur around the spinal cord, and also in other areas such as your arms and legs. Treatments vary but often include medicines and surgery.


Source: NIH: National Institute of Neurological Disorders and Stroke via

Epilepsy is a brain disorder that causes people to have recurring seizures. The seizures happen when clusters of nerve cells, or neurons, in the brain send out the wrong signals. People may have strange sensations and emotions or behave strangely. They may have violent muscle spasms or lose consciousness.
Epilepsy has many possible causes, including illness, brain injury and abnormal brain development. In many cases, the cause is unknown.
Doctors use brain scans and other tests to diagnose epilepsy. It is important to start treatment right away. There is no cure for epilepsy, but medicines can control seizures for most people. When medicines are not working well, surgery or implanted devices such as vagus nerve stimulators may help. Special diets can help some children with epilepsy.


Source: NIH: National Institute of Neurological Disorders and Stroke via

Meningitis is inflammation of the thin tissue that surrounds the brain and spinal cord, called the meninges. There are several types of meningitis. The most common is viral meningitis, which you get when a virus enters the body through the nose or mouth and travels to the brain. Bacterial meningitis is rare, but can be deadly. It usually starts with bacteria that cause a cold-like infection. It can block blood vessels in the brain and lead to stroke and brain damage. It can also harm other organs. Pneumococcal infections and meningococcal infections can cause bacterial meningitis.
Anyone can get meningitis, but it is more common in people whose bodies have trouble fighting infections. Meningitis can progress rapidly. You should seek medical care quickly if you have
  • A sudden fever
  • A severe headache
  • A stiff neck
Early treatment can help prevent serious problems, including death. Vaccines can prevent some of the bacterial infections that cause meningitis. Parents of adolescents and students living in college dorms should talk to a doctor about the vaccination.

Learning Activity 2.4: What disease are you most afraid to get?

Lesson 3: Cardiovascular Diseases and Disorders

Cardiovascular Diseases and Disorders

Source: Cardiovascular Diseases and Disorders, NLM, NIH, National Heart, Lung, and Blood Institute,

If you're like most people, you think that heart disease is a problem for other folks. But heart disease is the number one killer in the U.S. It is also a major cause of disability. There are many different forms of heart disease. The most common cause of heart disease is narrowing or blockage of the coronary arteries, the blood vessels that supply blood to the heart itself. This is called coronary artery disease and happens slowly over time. It's the major reason people have heart attacks.
Other kinds of heart problems may happen to the valves in the heart, or the heart may not pump well and cause heart failure. Some people are born with heart disease.

Heart disease is the leading cause of the death in the U.S. Over one quarter of all deaths are from heart disease. It is also a major cause of disability. The risk of heart disease increases as you age. You have a greater risk of heart disease if you are a man over age 45 or a woman over age 55. You also are at greater risk if you have a close family member who had heart disease at an early age.
Fortunately, there are many things you can do reduce your chances of getting heart disease. You should
  • Know your blood pressure and keep it under control
  • Exercise regularly
  • Don't smoke
  • Get tested for diabetes and if you have it, keep it under control
  • Know your cholesterol and triglyceride levels and keep them under control
  • Eat a lot of fruits and vegetables
  • Maintain a healthy weight
The vascular system is the body's network of blood vessels. It includes the arteries, veins and capillaries that carry blood to and from the heart. Problems of the vascular system are common and can be serious. Arteries can become thick and stiff, a problem called arteriosclerosis. Blood clots can clog vessels and block blood flow to the heart or brain. Weakened blood vessels can burst, causing bleeding inside the body.
You are more likely to have vascular disease as you get older. Other factors that make vascular disease more likely include
  • Family history of vascular or heart diseases
  • Pregnancy
  • Illness or injury
  • Long periods of sitting or standing still
  • Any condition that affects the heart and blood vessels, such as diabetes or high cholesterol
  • Smoking
  • Obesity
Losing weight, eating healthy foods, being active and not smoking can help vascular disease. Other treatments include medicines and surgery.

Learning Activity 3.1: Complete the Risk Assessment Tool for Estimating Your 10-year Risk of Having a Heart Attack.
  • Were there any surprises for you in the results?
  • If so, what are you going to do about it?

Heart Disease Risk Factors

This video—presented by the National Heart, Lung, and Blood Institute, part of the National Institutes of Health—discusses the risk factors for heart disease. You can control many heart disease risk factors, but some you cannot. Taking steps to prevent heart disease is key. For example, don’t smoke or quit smoking; aim for a healthy weight; be physically active; eat for heart health; know your cholesterol, blood pressure, and blood glucose numbers; and know your family’s medical history.
For more information, visit or the Health Topics Coronary Heart Disease Risk Factors and Heart Disease in Women articles.

Learning Activity 3.2:
Watch this video about Managing High Blood Pressure With Lifestyle Changes
This video—presented by the National Heart, Lung, and Blood Institute, part of the National Institutes of Health—shows how Kendra, the mother of a teenaged daughter, has learned to manage her high blood pressure. Before being diagnosed with high blood pressure, Kendra suffered from chronic headaches and tiredness. At a health fair sponsored by her company, Kendra learned that her blood pressure was high, which prompted her to see her doctor.
After being diagnosed with high blood pressure, Kendra made a commitment to living a healthier lifestyle. By following a healthy diet and being physically active, she lost almost 60 pounds. With the support of her girlfriend and daughter, Kendra has maintained her weight loss and continues to make lifestyle changes that allow her to live an active, happy life.

What Is Coronary Heart Disease?

Source: Coronary Heart Disease, NHLBI, NIH,

Coronary heart disease (CHD), also called coronary artery disease, is a condition in which plaque (pronounced: plak) builds up inside the coronary arteries. These arteries supply oxygen-rich blood to your heart muscle.
Plaque is made up of fat, cholesterol, calcium, and other substances found in the blood. When plaque builds up in the arteries, the condition is called atherosclerosis (ATH-er-o-skler-O-sis). The buildup of plaque occurs over many years.


Over time, plaque hardens and narrows your coronary arteries. This limits the flow of oxygen-rich blood to your heart muscle.mEventually, an area of plaque can rupture (break open). This causes a blood clot to form on the surface of the plaque. If the clot becomes large enough, it can mostly or completely block blood flow through a coronary artery.


If the flow of oxygen-rich blood to your heart muscle is reduced or blocked, angina (an-JI-nuh or AN-juh-nuh) or a heart attack may occur.
Angina is chest pain or discomfort. It may feel like pressure or squeezing in your chest. The pain also may occur in your shoulders, arms, neck, jaw, or back. Angina pain may even feel like indigestion.
A heart attack occurs if the flow of oxygen-rich blood to a section of heart muscle suddenly becomes blocked. If blood flow isn’t restored quickly, the section of heart muscle begins to die. Without quick treatment, a heart attack can lead to serious problems and even death.

Over time, CHD can weaken the heart muscle and lead to heart failure and arrhythmias (ah-RITH-me-ahs). Heart failure is a condition in which your heart can't pump enough blood to meet your body’s needs. Arrhythmias are problems with the rate or rhythm of the heartbeat.


CHD is the most common type of heart disease. In the United States, CHD is the #1 cause of death for both men and women. Lifestyle changes, medicines, and medical procedures can help prevent or treat CHD and may reduce the risk of related health problems.

Learning Activity 3.4: Watch Living With and Managing Coronary Artery Disease

This video—presented by the National Heart, Lung, and Blood Institute, part of the National Institutes of Health—describes coronary artery disease (CAD), its symptoms and complications, and ways to manage CAD risk factors.
CAD, also called coronary heart disease, is the leading cause of death for both men and women in the United States. CAD occurs if plaque builds up in the arteries of the heart. Plaque narrows the arteries and reduces blood flow to the heart muscle. This can lead to angina (chest pain or discomfort), a heart attack, heart failure, or arrhythmias (irregular heartbeats).
The good news is that lifestyle changes and medicines can help control CAD risk factors and prevent or delay the disease. Lifestyle changes include quitting smoking, following a healthy eating plan, maintaining a healthy weight, and being physically active.

What Causes Coronary Heart Disease?

Research suggests that coronary heart disease (CHD) starts when certain factors damage the inner layers of the coronary arteries. These factors include:
  • Smoking
  • High levels of certain fats and cholesterol in the blood
  • High blood pressure
  • High levels of sugar in the blood due to insulin resistance or diabetes
When damage occurs, your body starts a healing process. The healing may cause plaque to build up where the arteries are damaged.
The buildup of plaque in the coronary arteries may start in childhood. Over time, plaque can narrow or block some of your coronary arteries. This reduces the flow of oxygen-rich blood to your heart muscle.
Eventually, an area of plaque can rupture (break open). If this happens, blood cell fragments called platelets (PLATE-lets) will stick to the site of the injury and may clump together to form blood clots. Blood clots narrow the coronary arteries even more and worsen angina or cause a heart attack.

Who Is at Risk for Coronary Heart Disease?

In the United States, coronary heart disease (CHD) is the #1 cause of death for both men and women. Each year, more than half a million Americans die from CHD.
Certain traits, conditions, or habits—known as risk factors—may raise your risk for CHD. The more risk factors you have, the more likely you are to develop the disease.
You can control many risk factors, which may help prevent or delay CHD.

Major Risk Factors

  • Unhealthy blood cholesterol levels. This includes high LDL cholesterol (sometimes called “bad” cholesterol) and low HDL cholesterol (sometimes called “good” cholesterol).
  • High blood pressure. Blood pressure is considered high if it stays at or above 140/90 mmHg over time. If you have diabetes or chronic kidney disease, high blood pressure is defined as 130/80 mmHg or higher. (The mmHg is millimeters of mercury—the units used to measure blood pressure.)
  • Smoking. Smoking can damage and tighten blood vessels, lead to unhealthy cholesterol levels, and raise blood pressure. Smoking also can limit how much oxygen reaches the body's tissues.
  • Insulin resistance. This condition occurs if the body can't use its own insulin properly. Insulin is a hormone that helps move blood sugar into cells where it's used as an energy source. Insulin resistance may lead to diabetes.
  • Diabetes. With this disease, the body's blood sugar level is too high because the body doesn't make enough insulin or doesn't use its insulin properly.
  • Overweight or obesity. The terms “overweight” and “obesity” refer to body weight that’s greater than what is considered healthy for a certain height.
  • Metabolic syndrome. Metabolic syndrome is the name for a group of risk factors that raises your risk for CHD and other health problems, such as diabetes and stroke.
  • Lack of physical activity. Lack of physical activity can worsen other risk factors for CHD, such as unhealthy blood cholesterol levels, high blood pressure, diabetes, and overweight or obesity.
  • Unhealthy diet. An unhealthy diet can raise your risk for CHD. Foods that are high in saturated and trans fats, cholesterol, sodium (salt), and sugar can worsen other risk factors for CHD.
  • Older age. As you get older, your risk for CHD increases. Genetic or lifestyle factors cause plaque to build up in your arteries as you age. By the time you're middle-aged or older, enough plaque has built up to cause signs or symptoms.
    • In men, the risk for CHD increases after age 45.
    • In women, the risk for CHD increases after age 55.
  • Family history of early heart disease. Your risk increases if your father or a brother was diagnosed with CHD before 55 years of age, or if your mother or a sister was diagnosed with CHD before 65 years of age.
Although older age and a family history of early heart disease are risk factors, it doesn't mean that you’ll develop CHD if you have one or both. Controlling other risk factors often can lessen genetic influences and prevent CHD, even in older adults.

Emerging Risk Factors

Researchers continue to study other possible risk factors for CHD.
High levels of a protein called C-reactive protein (CRP) in the blood may raise the risk for CHD and heart attack. High levels of CRP are a sign of inflammation in the body.
Inflammation is the body's response to injury or infection. Damage to the arteries' inner walls may trigger inflammation and help plaque grow.
Research is under way to find out whether reducing inflammation and lowering CRP levels also can reduce the risk for CHD and heart attack.
High levels of triglycerides (tri-GLIH-seh-rides) in the blood also may raise the risk for CHD, especially in women. Triglycerides are a type of fat.

Other Risks Related to Coronary Heart Disease

Other conditions and factors also may contribute to CHD, including:
  • Sleep apnea. Sleep apnea is a common disorder in which you have one or more pauses in breathing or shallow breaths while you sleep. Untreated sleep apnea can increase your risk for high blood pressure, diabetes, and even a heart attack or stroke.
  • Stress. Research shows that the most commonly reported "trigger" for a heart attack is an emotionally upsetting event, especially one involving anger.
  • Alcohol. Heavy drinking can damage the heart muscle and worsen other risk factors for CHD. Men should have no more than two drinks containing alcohol a day. Women should have no more than one drink containing alcohol a day.
  • Preeclampsia (pre-e-KLAMP-se-ah). This condition can develop during pregnancy. The two main signs of preeclampsia are a rise in blood pressure and excess protein in the urine. Preeclampsia is linked to an increased lifetime risk of heart disease, including CHD, heart attack, heart failure, and high blood pressure.

What Are the Signs and Symptoms of Coronary Heart Disease?

A common symptom of coronary heart disease (CHD) is angina. Angina is chest pain or discomfort that occurs if an area of your heart muscle doesn't get enough oxygen-rich blood.
Angina may feel like pressure or squeezing in your chest. You also may feel it in your shoulders, arms, neck, jaw, or back. Angina pain may even feel like indigestion. The pain tends to get worse with activity and go away with rest. Emotional stress also can trigger the pain.
Another common symptom of CHD is shortness of breath. This symptom happens if CHD causes heart failure. When you have heart failure, your heart can't pump enough blood to meet your body’s needs. Fluid builds up in your lungs, making it hard to breathe.
The severity of these symptoms varies. They may get more severe as the buildup of plaque continues to narrow the coronary arteries.

Signs and Symptoms of Heart Problems Related to Coronary Heart Disease

Some people who have CHD have no signs or symptoms, a condition called silent CHD. The disease may not be diagnosed until a person has signs or symptoms of a heart attack, heart failure, or an arrhythmia (an irregular heartbeat).

Learning Activity 3.5: Watch this short video titled Heart Attack Warning Symptoms. It speaks to the 7 main symptoms of a heart attack. It uses real women's stories to personalize the heart attack experience, and encourages women who experience these symptoms to get checked out.

This video is presented by the NIH's National Heart, Lung, and Blood Institute.

Heart Attack

Source: Heart Attack, NIH, National Heart, Lung, and Blood Institute, Medline,

Each year over a million people in the U.S. have a heart attack. About half of them die. Many people have permanent heart damage or die because they don't get help immediately. It's important to know the symptoms of a heart attack and call 9-1-1 if someone is having them. Those symptoms include
  • Chest discomfort - pressure, squeezing, or pain
  • Shortness of breath
  • Discomfort in the upper body - arms, shoulder, neck, back
  • Nausea, vomiting, dizziness, lightheadedness, sweating
These symptoms can sometimes be different in women.
What exactly is a heart attack? Most heart attacks happen when a clot in the coronary artery blocks the supply of blood and oxygen to the heart. Often this leads to an irregular heartbeat - called an arrhythmia - that causes a severe decrease in the pumping function of the heart. A blockage that is not treated within a few hours causes the affected heart muscle to die.

Heart With Muscle Damage and a Blocked Artery

The most common heart attack symptom is chest pain or discomfort. Most heart attacks involve discomfort in the center or left side of the chest that often lasts for more than a few minutes or goes away and comes back.
The discomfort can feel like uncomfortable pressure, squeezing, fullness, or pain. The feeling can be mild or severe. Heart attack pain sometimes feels like indigestion or heartburn.
The symptoms of angina can be similar to the symptoms of a heart attack. Angina pain usually lasts for only a few minutes and goes away with rest.
Chest pain or discomfort that doesn’t go away or changes from its usual pattern (for example, occurs more often or while you’re resting) can be a sign of a heart attack. If you don’t know whether your chest pain is angina or a heart attack, call 9–1–1.
All chest pain should be checked by a doctor.
Other common signs and symptoms of a heart attack include:
  • Upper body discomfort in one or both arms, the back, neck, jaw, or upper part of the stomach
  • Shortness of breath, which may occur with or before chest discomfort
  • Nausea (feeling sick to your stomach), vomiting, light-headedness or fainting, or breaking out in a cold sweat
  • Sleep problems, fatigue (tiredness), or lack of energy

Heart Failure

Heart failure is a condition in which your heart can't pump enough blood to meet your body’s needs. Heart failure doesn't mean that your heart has stopped or is about to stop working.
The most common signs and symptoms of heart failure are shortness of breath or trouble breathing; fatigue; and swelling in the ankles, feet, legs, stomach, and veins in the neck.
All of these symptoms are the result of fluid buildup in your body. When symptoms start, you may feel tired and short of breath after routine physical effort, like climbing stairs.


An arrhythmia is a problem with the rate or rhythm of the heartbeat. When you have an arrhythmia, you may notice that your heart is skipping beats or beating too fast.
Some people describe arrhythmias as a fluttering feeling in the chest. These feelings are called palpitations (pal-pi-TA-shuns). Some arrhythmias can cause your heart to suddenly stop beating. This condition is called sudden cardiac arrest (SCA). SCA usually causes death if it's not treated within minutes.

How Can Coronary Heart Disease Be Prevented or Delayed?

Taking action to control your risk factors can help prevent or delay coronary heart disease (CHD). Your risk for CHD increases with the number of risk factors you have.
  • One step you can take is to adopt a healthy lifestyle. Following a healthy diet is an important part of a healthy lifestyle.
  • A healthy diet includes a variety of fruits, vegetables, and whole grains. It also includes lean meats, poultry, fish, beans, and fat-free or low-fat milk or milk products. A healthy diet is low in saturated fat, trans fat, cholesterol, sodium (salt), and added sugar.
  • If you're overweight or obese, work with your doctor to create a reasonable weight-loss plan. Controlling your weight helps you control CHD risk factors.
  • Be as physically active as you can. Physical activity can improve your fitness level and your health. Talk with your doctor about what types of activity are safe for you.
  • If you smoke, quit. Smoking can damage and tighten blood vessels and raise your risk for CHD. Talk with your doctor about programs and products that can help you quit. Also, try to avoid secondhand smoke.
  • Know your family history of health problems related to CHD. If you or someone in your family has CHD, be sure to tell your doctor.
  • If lifestyle changes aren't enough, you also may need medicines to control your CHD risk factors. Take all of your medicines as prescribed.

Learning Activity 3.6: Watch this 3 minute video by the National Heart, Lung, and Blood Institute titled, Managing High Blood Pressure With Lifestyle Changes.
This video shows how Kendra, the mother of a teenaged daughter, has learned to manage her high blood pressure. Before being diagnosed with high blood pressure, Kendra suffered from chronic headaches and tiredness. At a health fair sponsored by her company, Kendra learned that her blood pressure was high, which prompted her to see her doctor.
After being diagnosed with high blood pressure, Kendra made a commitment to living a healthier lifestyle. By following a healthy diet and being physically active, she lost almost 60 pounds. With the support of her girlfriend and daughter, Kendra has maintained her weight loss and continues to make lifestyle changes that allow her to live an active, happy life.


Source: Angina, NIH, National Heart, Lung, and Blood Institute, Medline,

Angina is chest pain or discomfort you get when your heart muscle does not get enough blood. It may feel like pressure or a squeezing pain in your chest. It may feel like indigestion. You may also feel pain in your shoulders, arms, neck, jaw or back.
Angina is a symptom of coronary artery disease (CAD), the most common heart disease. CAD happens when a sticky substance called plaque builds up in the arteries that supply blood to the heart, reducing blood flow.
There are three types of angina: stable, unstable and variant. Unstable angina is the most dangerous. It does not follow a pattern and can happen without physical exertion. It does not go away with rest or medicine. It is a sign that you could have a heart attack soon.
Not all chest pain or discomfort is angina. If you have chest pain, you should see your health care provider.

Congestive heart failure

Source: Congestive Heart Failure, NIH, National Heart, Lung, and Blood Institute, Medline,

Heart failure is a condition in which the heart can't pump enough blood throughout the body. Heart failure does not mean that your heart has stopped or is about to stop working. It means that your heart is not able to pump blood the way it should.
The weakening of the heart's pumping ability causes
  • Blood and fluid to back up into the lungs
  • The buildup of fluid in the feet, ankles and legs - called edema
  • Tiredness and shortness of breath
The leading causes of heart failure are coronary artery disease, high blood pressure and diabetes.
Treatment includes treating the underlying cause of your heart failure, medicines, and heart transplantation if other treatments fail.
Heart failure is a serious condition. About 5 million people in the U.S. have heart failure. It contributes to 300,000 deaths each year.

Congenital heart disorders

Source: Congenital Heart Disorders, NIH, National Heart, Lung, and Blood Institute, Medline,

A congenital heart defect is a problem with the structure of the heart. It is present at birth. Congenital heart defects are the most common type of major birth defect.
A baby's heart begins to develop shortly after conception. During development, structural defects can occur. These defects can involve the walls of the heart, the valves of the heart and the arteries and veins near the heart. Congenital heart defects can disrupt the normal flow of blood through the heart. The blood flow can
  • Slow down
  • Go in the wrong direction or to the wrong place
  • Be blocked completely
Treatment for the defect can include medicines, surgery and other medical procedures and heart transplants. The treatment depends on the type and severity of the defect and a child's age, size and general health. Today, many children born with complex heart defects grow to adulthood and lead productive lives.


Source: Stroke, NIH, National Institute of Neurological Disorders and Stroke via,

A stroke is a medical emergency. Strokes happen when blood flow to your brain stops. Within minutes, brain cells begin to die. There are two kinds of stroke. The more common kind, called ischemic stroke, is caused by a blood clot that blocks or plugs a blood vessel in the brain. The other kind, called hemorrhagic stroke, is caused by a blood vessel that breaks and bleeds into the brain. "Mini-strokes" or transient ischemic attacks (TIAs), occur when the blood supply to the brain is briefly interrupted.
Symptoms of stroke are -
  • Sudden numbness or weakness of the face, arm or leg (especially on one side of the body)
  • Sudden confusion, trouble speaking or understanding speech
  • Sudden trouble seeing in one or both eyes
  • Sudden trouble walking, dizziness, loss of balance or coordination
  • Sudden severe headache with no known cause
If you have any of these symptoms, you must get to a hospital quickly to begin treatment. Acute stroke therapies try to stop a stroke while it is happening by quickly dissolving the blood clot or by stopping the bleeding. Post-stroke rehabilitation helps individuals overcome disabilities that result from stroke damage. Drug therapy with blood thinners is the most common treatment for stroke.

Incidence of Stroke

Source: Incidence of Stroke, Centers for Disease Control,

Every 40 seconds, someone in the United States has a stroke. In 2008 alone, more than 133,000 Americans died from stroke—or one person every four minutes— making it the fourth leading cause of death in the United States.
A stroke, sometimes called a brain attack, occurs when a blockage stops the flow of blood to the brain or when a blood vessel in or around the brain bursts. Although many people think of stroke as a condition that affects only older adults, strokes can and do occur in people of all ages. In fact, nearly a quarter of all strokes occur in people younger than age 65.
Each year, almost 800,000 strokes occur in the United States. Strokes often lead to serious, life-changing complications that include:
  • Paralysis or weakness on one side of the body.
  • Problems with thinking, awareness, attention, learning, judgment, and memory.
  • Problems understanding or forming speech.
  • Difficulty controlling or expressing emotions.
  • Numbness or strange sensations.
  • Pain in the hands and feet.
  • Depression.
To help protect yourself and your loved ones, learn what steps you can take to prevent a stroke and how to spot a stroke if one occurs.

Lowering Your Risk for Stroke

Demographic factors such as family history, age, sex, and race/ethnicity can all play a role in an individual's stroke risk. Regardless of your background, however, there are several things you can do to lower your chances of having a stroke.
doctor taking blood pressure reading
doctor taking blood pressure reading
For example, cigarette smoking contributes to one in every five strokes in the United States. Smoking—and even exposure to second-hand smoke—can thicken the blood and make it more likely to clot. Thicker blood flow can lead to increased plaque buildup in your arteries and damage to the blood vessels leading to the brain, which can cause or worsen a stroke. So, quit smoking—or better yet, don't start.
In 2011, the Department of Health and Human Services launched the Million Hearts™
External Web Site Icon
External Web Site Icon
initiative to prevent a million heart attacks and strokes by 2017. A primary focus is on the ABCS to prevent cardiovascular disease, including stroke, and contribute to overall health
  • Appropriate Aspirin therapy
    • Ask your doctor if taking aspirin is right for you.
  • Blood pressure control
    • Keeping your blood pressure under control reduces your risk of heart attack and stroke. More than half of the world's stroke deaths are caused by elevated blood pressure levels.
  • Cholesterol management
    • Get your cholesterol checked regularly and manage it with diet and physical activity or with medication, if needed.
  • Smoking cessation
  • Exercise regularly.
  • Eat a healthy diet that's low in sodium.
  • Maintain a healthy weight.
  • Prevent or control diabetes.
  • Limit your alcohol intake (fewer than two drinks per day for men, or one drink per day for women).

Recognizing the Signs of Stroke

When responding to a stroke, every minute counts. The sooner a patient receives medical treatment, the lower the risk for death or disability. If you or someone you know exhibits the following signs or symptoms, call 9-1-1 immediately:
  • Numbness or weakness of the face, arm, or leg, especially on one side of the body
  • Confusion, trouble speaking, or difficulty understanding
  • Trouble seeing in one or both eyes
  • Trouble walking, dizziness, or loss of balance and coordination
  • Severe headache with no known cause

Optional Learning Activity: Learn about CPR at Be The Beat, an online Sudden Cardiac Arrest awareness initiative to teach the simple steps that can save a life.

Lesson 4: Cancer


Source: Cancer, NIH: National Cancer Institute via MedlinePlus,
Cancer begins in your cells, which are the building blocks of your body. Normally, your body forms new cells as you need them, replacing old cells that die. Sometimes this process goes wrong. New cells grow even when you don't need them, and old cells don't die when they should. These extra cells can form a mass called a tumor. Tumors are abnormal growths in your body. They are made up of extra cells. Normally, old cells die, and new ones take their place. Sometimes, however, this process goes wrong. New cells form even when you don't need them, and old cells don't die when they should. When these extra cells form a mass, it is called a tumor.
Tumors can be either benign or malignant. Benign tumors aren't cancer. Malignant ones are. Benign tumors grow only in one place. They cannot spread or invade other parts of your body. Even so, they can be dangerous if they press on vital organs, such as your brain. Treatment often involves surgery. Benign tumors usually don't grow back.
Cells from malignant tumors can invade nearby tissues. They can also break away and spread to other parts of the body.

Most cancers are named for where they start. For example, lung cancer starts in the lung, and breast cancer starts in the breast. The spread of cancer from one part of the body to another is called metastasis. Symptoms and treatment depend on the cancer type and how advanced it is.


Treatment plans may include surgery, radiation and/or chemotherapy.
Radiation is a form of energy released in particles or waves. In high doses, radiation destroys cells or keeps them from multiplying.
Radiation therapy is a cancer treatment. Its goal is to kill cancer cells and shrink tumors. Unlike cancer cells, most of your normal cells recover from radiation therapy. Doctors try to protect normal cells by limiting the radiation dosage and spreading treatment out over time. When they use radiation machines, they shield as much of your body as possible while targeting the cancer.
Normally, your cells grow and die in a controlled way. Cancer cells keep forming without control. Chemotherapy is drug therapy that can kill these cells or stop them from multiplying. However, it can also harm healthy cells, which causes side effects.
During chemotherapy you may have no side effects or just a few. The kinds of side effects you have depend on the type and dose of chemotherapy you get. Side effects vary, but common ones are nausea, vomiting, tiredness, pain and hair loss. Healthy cells usually recover after chemotherapy, so most side effects gradually go away.
Your course of therapy will depend on the cancer type, the chemotherapy drugs used, the treatment goal and how your body responds. You may get treatment every day, every week or every month. You may have breaks between treatments so that your body has a chance to build new healthy cells. You might take the drugs by mouth, in a shot or intravenously.

Learning Activity 4.1: Go to this interactive website to understand cancer risk factors.

What Is Risk?

Do you know the four types of risk factors that affect your cancer risk? Or that your level of contact with these risk factors can affect your risk? This section explains the concept of risk and lets you test your knowledge of the subject.

Can I Lower My Risk?

Here you can explore your risk for 6 cancers: breast, cervical, colon, lung, prostate, and skin. What are the risk factors for each of these cancers? Which risk factors apply to you? And what can you do to reduce your risk?

Is This News Story True?

You've heard the stories about things like cell phones and deodorants causing cancer. How do you decide if the stories you find in the media are accurate? Learn how to analyze what you see or hear in the news.

**Analyze the Media**
It is important to analyze what you read in the paper, see on television, hear on the radio, or find on the Internet. A good analysis will help you determine whether the information is likely to be accurate. Below is a list of questions to consider when you hear about new cancer research studies.
  • Who is reporting the results?
    • Is the newspaper, radio or TV station, or Internet site a reliable source of medical news? You might want to talk to your health care provider to help you judge the reliability of the source.
  • Was the study based in the laboratory, on animals, or on people?
    • The results of research on people are more likely to be meaningful to you.
  • How large is the study?
    • In general, when it comes to understanding medical risks, the larger the study the more valid the data will be for the general population.
  • Does it include people like you?
    • Check to see if some of the people in the study were the same age, sex, ethnic background, income group as yourself and had the same health concerns.
  • Are the results presented in an easy-to-understand way?
    • They should use absolute risk, relative risk, or some other easy-to-understand number.
  • Does the report clearly tell what behavior or medical treatment was studied?
    • Information about the study should include what behavior or medical treatment was being studied. It should also include what outcomes, such as lower cancer risk or increased detection, were measured in the study.
  • What are other possible explanations for the study results?
    • Researchers should discuss other possible explanations for the results. These may include other risk factors or problems with the research.
  • Where was the research done?
    • Scientists at a medical school or large hospital, for example, might be better able to conduct complex experiments or have more experience.
  • Has the study been published in a peer-reviewed journal?
    • Medical journals use a peer review process to help ensure the quality of the research. (Peer review is an appraisal of research against accepted standards by professionals in the field.)

Skin Cancer


Skin cancer is the most common form of cancer in the United States. The two most common types of skin cancer—basal cell and squamous cell carcinomas—are highly curable. However, melanoma, the third most common skin cancer, is more dangerous. About 65%–90% of melanomas are caused by exposure to ultraviolet (UV) light.
Each year, more than 68,000 Americans are diagnosed with melanoma, and another 48,000 are diagnosed with an early form of the disease that involves only the top layer of skin. Also, more than 2 million people are treated for basal cell or squamous cell skin cancer each year. Basal cell skin cancer is several times more common than squamous cell skin cancer.
Skin cancers are named for the type of cells that become malignant (cancer). The three most common types are:
  • Melanoma: Melanoma begins in melanocytes (pigment cells). Most melanocytes are in the skin. See the picture of a melanocyte and other skin cells. Melanoma can occur on any skin surface. In men, it's often found on the skin on the head, on the neck, or between the shoulders and the hips. In women, it's often found on the skin on the lower legs or between the shoulders and the hips.

    Melanoma is rare in people with dark skin. When it does develop in people with dark skin, it's usually found under the fingernails, under the toenails, on the palms of the hands, or on the soles of the feet.
  • Basal cell skin cancer: Basal cell skin cancer begins in the basal cell layer of the skin. It usually occurs in places that have been in the sun. For example, the face is the most common place to find basal cell skin cancer.In people with fair skin, basal cell skin cancer is the most common type of skin cancer.
  • Squamous cell skin cancer: Squamous cell skin cancer begins in squamous cells. In people with dark skin, squamous cell skin cancer is the most common type of skin cancer, and it's usually found in places that are not in the sun, such as the legs or feet.
    However, in people with fair skin, squamous cell skin cancer usually occurs on parts of the skin that have been in the sun, such as the head, face, ears, and neck.
Unlike moles, skin cancer can invade the normal tissue nearby. Also, skin cancer can spread throughout the body. Melanoma is more likely than other skin cancers to spread to other parts of the body. Squamous cell skin cancer sometimes spreads to other parts of the body, but basal cell skin cancer rarely does.
When skin cancer cells do spread, they break away from the original growth and enter blood vessels or lymph vessels. The cancer cells may be found in nearby //lymph nodes//. The cancer cells can also spread to other tissues and attach there to form new tumors that may damage those tissues. The spread of cancer is called //metastasis//.

Symptoms of Melanoma

Often the first sign of melanoma is a change in the shape, color, size, or feel of an existing mole. Melanoma may also appear as a new mole. Thinking of "ABCDE" can help you remember what to look for:
  • Asymmetry: The shape of one half does not match the other half.
  • Border that is irregular: The edges are often ragged, notched, or blurred in outline. The pigment may spread into the surrounding skin.
  • Color that is uneven: Shades of black, brown, and tan may be present. Areas of white, gray, red, pink, or blue may also be seen.
  • Diameter: There is a change in size, usually an increase. Melanomas can be tiny, but most are larger than the size of a pea (larger than 6 millimeters or about 1/4 inch).
  • Evolving: The mole has changed over the past few weeks or months.
Melanomas can vary greatly in how they look. Many show all of the ABCDE features. However, some may show changes or abnormal areas in only one or two of the ABCDE features.
In more advanced melanoma, the texture of the mole may change. The skin on the surface may break down and look scraped. It may become hard or lumpy. The surface may ooze or bleed. Sometimes the melanoma is itchy, tender, or painful.
Visit the National Cancer Institute's Symptoms of Melanoma webpage to view photos of an asymetric melanoma and a dysplastic nevus.

A change on the skin is the most common sign of skin cancer. This may be a new growth, a sore that doesn't heal, or a change in an old growth. Not all skin cancers look the same. Usually, skin cancer is not painful. To view photos of basal cell and squamous Cell Skin Cancers, see Symptoms.
Common symptoms of basal cell or squamous cell skin cancer include:
  • A lump that is small, smooth, shiny, pale, or waxy
  • A lump that is firm and red
  • A sore or lump that bleeds or develops a crust or a scab
  • A flat red spot that is rough, dry, or scaly and may become itchy or tender
  • A red or brown patch that is rough and scaly

Risk Factors

When you're told that you have skin cancer, it's natural to wonder what may have caused the disease. The main risk factor for skin cancer is exposure to sunlight (UV radiation), but there are also other risk factors. A risk factor is something that may increase the chance of getting a disease.
People with certain risk factors are more likely than others to develop skin cancer. Some risk factors vary for the different types of skin cancer.

Risks for Any Type of Skin Cancer

Studies have shown that the following are risk factors for the three most common types of skin cancer:
  • Sunlight: Sunlight is a source of UV radiation. It's the most important risk factor for any type of skin cancer. The sun's rays cause skin damage that can lead to cancer.
  • Severe, blistering sunburns: People who have had at least one severe, blistering sunburn are at increased risk of skin cancer. Although people who burn easily are more likely to have had sunburns as a child, sunburns during adulthood also increase the risk of skin cancer.
  • Lifetime sun exposure: The total amount of sun exposure over a lifetime is a risk factor for skin cancer.
  • Tanning: Although a tan slightly lowers the risk of sunburn, even people who tan well without sunburning have a higher risk of skin cancer because of more lifetime sun exposure.
Sunlight can be reflected by sand, water, snow, ice, and pavement. The sun's rays can get through clouds, windshields, windows, and light clothing.
In the United States, skin cancer is more common where the sun is strong. For example, more people in Texas than Minnesota get skin cancer. Also, the sun is stronger at higher elevations, such as in the mountains.
Doctors encourage people to limit their exposure to sunlight.
  • Sunlamps and tanning booths: Artificial sources of UV radiation, such as sunlamps and tanning booths, can cause skin damage and skin cancer. Health care providers strongly encourage people, especially young people, to avoid using sunlamps and tanning booths. The risk of skin cancer is greatly increased by using sunlamps and tanning booths before age 30.
  • Personal history: People who have had melanoma have an increased risk of developing other melanomas. Also, people who have had basal cell or squamous cell skin cancer have an increased risk of developing another skin cancer of any type.
  • Family history: Melanoma sometimes runs in families. Having two or more close relatives (mother, father, sister, brother, or child) who have had this disease is a risk factor for developing melanoma.
  • Skin that burns easily: Having fair (pale) skin that burns in the sun easily, blue or gray eyes, red or blond hair, or many freckles increases the risk of skin cancer.
  • Certain medical conditions or medicines: Medical conditions or medicines (such as some antibiotics, hormones, or antidepressants) that make your skin more sensitive to the sun increase the risk of skin cancer. Also, medical conditions or medicines that suppress the immune system increase the risk of skin cancer.

Other Risk Factors for Melanoma

The following risk factors increase the risk of melanoma:
  • **Dysplastic nevus**: A dysplastic nevus is a type of mole that looks different from a common mole. A dysplastic nevus may be bigger than a common mole, and its color, surface, and border may be different. It's usually wider than a pea and may be longer than a peanut. A dysplastic nevus can have a mixture of several colors, from pink to dark brown. Usually, it's flat with a smooth, slightly scaly or pebbly surface, and it has an irregular edge that may fade into the surrounding skin. A dysplastic nevus is more likely than a common mole to turn into cancer. However, most do not change into melanoma. A doctor will remove a dysplastic nevus if it looks like it might have changed into melanoma.
  • More than 50 common moles: Usually, a common mole is smaller than a pea, has an even color (pink, tan, or brown), and is round or oval with a smooth surface. Having many common moles increases the risk of developing melanoma.

Symptoms of Melanoma

Often the first sign of melanoma is a change in the shape, color, size, or feel of an existing mole. Melanoma may also appear as a new mole. Thinking of "ABCDE" can help you remember what to look for:
  • Asymmetry: The shape of one half does not match the other half.
  • Border that is irregular: The edges are often ragged, notched, or blurred in outline. The pigment may spread into the surrounding skin.
  • Color that is uneven: Shades of black, brown, and tan may be present. Areas of white, gray, red, pink, or blue may also be seen.
  • Diameter: There is a change in size, usually an increase. Melanomas can be tiny, but most are larger than the size of a pea (larger than 6 millimeters or about 1/4 inch).
  • Evolving: The mole has changed over the past few weeks or months.
Melanomas can vary greatly in how they look. Many show all of the ABCDE features. However, some may show changes or abnormal areas in only one or two of the ABCDE features.
In more advanced melanoma, the texture of the mole may change. The skin on the surface may break down and look scraped. It may become hard or lumpy. The surface may ooze or bleed. Sometimes the melanoma is itchy, tender, or painful.

How To Check Your Skin

Your doctor or nurse may suggest that you do a regular skin self-exam to check for the development of a new skin cancer.
The best time to do this exam is after a shower or bath. Check your skin in a room with plenty of light. Use a full-length mirror and a hand-held mirror.
It's best to begin by learning where your birthmarks, moles, and other marks are and their usual look and feel.
Check for anything new:
  • A new mole (that looks different from your other moles)
  • A new red or darker color flaky patch that may be a little raised
  • A new flesh-colored firm bump
  • A change in the size, shape, color, or feel of a mole
  • A sore that doesn't heal
Check yourself from head to toe:
  • Look at your face, neck, ears, and scalp. You may want to use a comb or a blow dryer to move your hair so that you can see better. You also may want to have a relative or friend check through your hair. It may be hard to check your scalp by yourself.
  • Look at the front and back of your body in the mirror. Then, raise your arms and look at your left and right sides.
  • Bend your elbows. Look carefully at your fingernails, palms, forearms (including the undersides), and upper arms.
  • Examine the back, front, and sides of your legs. Also look around your genital area and between your buttocks.
  • Sit and closely examine your feet, including your toenails, your soles, and the spaces between your toes.
By checking your skin regularly, you'll learn what is normal for you. It may be helpful to record the dates of your skin exams and to write notes about the way your skin looks. If your doctor has taken photos of your skin, you can compare your skin to the photos to help check for changes. If you find anything unusual, see your doctor.

Learning Activity 4.2:

Check out your risk of melanoma using the Melanoma Cancer Risk Assessment Tool.

This is an interactive tool that allows doctors to estimate a person's absolute risk of developing invasive melanoma (skin cancer) over the next 5 years for people age 20 to 70 years. The tool allows doctors to identify individuals at higher risk of melanoma in order to plan appropriate screening interventions with them.

What is breast cancer?

Source: Breast Cancer Facts, CDC,

Cancer is a disease in which cells in the body grow out of control. When cancer starts in the breast, it is called breast cancer. The breast is made up of three main parts: glands, ducts, and connective tissue. Sometimes, breast cells become abnormal and grow faster than normal cells. These extra cells form a mass called a tumor. Some tumors are “benign,” or not cancerous. Other tumors are “malignant,” meaning they are cancerous and have the ability to spread to other parts of the breast and body and disrupt normal functions in those areas.
All women are at risk for breast cancer.

Men can also get breast cancer, but this is rare. Breast cancer is the second most common cancer in women. Among Hispanic women, it is the most common cause of cancer deaths, and it is the second most common cause of cancer deaths among white, black, Asian or Pacific Islander, and American Indian or Alaska Native women. Although more white women get breast cancer, more black women die from it. Each year, approximately 190,000 women are diagnosed with breast cancer and 40,000 women die from the disease.

What puts me at greater risk?

Several factors may affect your risk of developing breast cancer, including:
  • Getting older
  • Not having children, or having your first child later in life
  • Starting your first menstrual period at an early age
  • Beginning menopause at a late age
  • Having a personal history of breast cancer or certain benign breast diseases, such as atypical ductal hyperplasia
  • Having close family relatives (such as a mother, sister, father, or daughter) who have had breast cancer
  • Having a genetic condition, such as certain mutations in your BRCA1 or BRCA2 genes
  • Having been treated with radiation therapy to the breast or chest
  • Being overweight, particularly after menopause
  • Using hormone replacement therapy for a long time
  • Using oral contraceptives
  • Drinking alcohol
  • Being physically inactive

What are the symptoms?

When breast cancer starts out, it is too small to feel and does not cause signs and symptoms. As it grows, however, breast cancer can cause changes in how the breast looks or feels. Symptoms may include:
  • A new lump in the breast
  • A lump that has changed
  • A change in the size or shape of the breast
  • Pain in the breast or nipple that does not go away
  • Flaky, red, or swollen skin anywhere on the breast
  • A nipple that is very tender or that turns inward
  • Blood or any other type of fluid coming from the nipple that is not milk when nursing a baby
These symptoms may be caused by something other than cancer, but the only way to know is to get checked.

How can I find out if I have breast cancer?

Women should begin to have routine screenings for breast cancer at the age of 50. Women under the age of 50 should talk to their health care provider about when and how often they should be screened. If you have any risk factors or symptoms of breast cancer, talk to a doctor, nurse, or health care professional.

A mammogram is the best test for finding breast cancer early. It is a series of X-ray pictures of the breast that allow doctors to look for early signs of breast cancer, sometimes up to three years before it can be felt. If your mammogram is abnormal or more tests are required, do not panic. An abnormal mammogram does not always mean you have cancer. It does mean that you will need to have some additional X-rays or other tests before your doctor can be sure. Other tests may include an ultrasound (picture taken of the breast using sound waves) or a biopsy (removing tissue samples to be looked at closely under a microscope). You may be referred to a breast specialist or a surgeon, because these doctors are experts in diagnosing breast problems. Treatment is most effective when breast cancer is
found early, and many women go on to live long and healthy lives. How can I prevent breast cancer?

Scientists are studying how best to prevent breast cancer. There are things you can do to help lower your risk of getting breast cancer, including:
  • Staying physically active with regular exercise
  • Maintaining a healthy weight
  • Avoiding hormone replacement therapy (HRT), or finding out the risks and benefits of HRT and if it is right for you
  • Limiting the amount of alcohol that you drink

Optional Learning Activity:

Check out your risk of getting breast cancer using the The Breast Cancer Risk Assessment Tool.

This is an interactive tool that allows doctors to estimate a woman's absolute risk of developing invasive breast cancer over the next 5 years for women age 35 to 90 years (lifetime risk) based on the woman's age and the risk factor information provided.

Colorectal Cancer

Source: NIH: National Cancer Institute,

Colorectal cancer is cancer of the rectum or colon. It’s the second leading cause of cancer-related death for both men and women.
People over the age of 50 are at the highest risk for colorectal cancer. Other risk factors include:
  • Growths (called polyps) inside the colon
  • Family history of colorectal cancer
  • Smoking
  • Health conditions like Crohn’s Disease
  • Being African-American
Here’s the good news: you can reduce your risk if you get screened for colorectal cancer starting at the age of 50. You can also reduce your risk of colorectal cancer by:
  • Getting active
  • Eating healthy
  • Quitting smoking

Learning Activity 4.2: Go to this interactive website to understand risks for colorectal cancer.

This is an interactive tool designed to help people and their healthcare providers make informed choices about colorectal screening. The tool uses a respondent's answers to an online questionnaire to calculate that person's 5-year, 10-year, and lifetime risk of developing colorectal cancer.

Lung Cancer

Source: Lung Cancer, NIH: National Cancer Institute,

Lung cancer is one of the most common cancers in the world. It is a leading cause of cancer death in men and women in the United States. Cigarette smoking causes most lung cancers. The more cigarettes you smoke per day and the earlier you started smoking, the greater your risk of lung cancer. High levels of pollution, radiation and asbestos exposure may also increase risk.
Common symptoms of lung cancer include
  • A cough that doesn't go away and gets worse over time
  • Constant chest pain
  • Coughing up blood
  • Shortness of breath, wheezing, or hoarseness
  • Repeated problems with pneumonia or bronchitis
  • Swelling of the neck and face
  • Loss of appetite or weight loss
  • Fatigue
There are many types of lung cancer. Each type of lung cancer grows and spreads in different ways and is treated differently. Treatment also depends on the stage, or how advanced it is. Treatment may include chemotherapy, radiation and surgery.

Ovarian Cancer

The sooner ovarian cancer is found and treated, the better your chance for recovery. But ovarian cancer is hard to detect early. Many times, women with ovarian cancer have no symptoms or just mild symptoms until the disease is in an advanced stage and hard to treat. Symptoms may include:
  • Heavy feeling in pelvis
  • Pain in lower abdomen
  • Bleeding from the vagina
  • Weight gain or loss
  • Abnormal periods
  • Unexplained back pain that gets worse
  • Gas, nausea, vomiting, or loss of appetite
Treatment is usually surgery followed by treatment with medicines called chemotherapy.

Prostate Cancer

Source: U.S. Cancer Statistics Working Group. //United States Cancer Statistics: 1999–2007 Incidence and Mortality Web-based Report.// Atlanta (GA): Department of Health and Human Services, Centers for Disease Control and Prevention, and National Cancer Institute; 2010. Available at:

Prostate cancer is the most common cancer in men. Ask your doctor about the potential benefits and harms of prostate cancer screening tests.
Cancer is a disease in which abnormal cells in the body grow out of control. When cancer starts in the prostate, it is called prostate cancer. The prostate is a walnut-sized organ located just below the bladder and in front of the rectum in men. It produces fluid that makes up a part of semen.
Prostate cancer is the most commonly diagnosed cancer in men, and second only to lung cancer in the number of cancer deaths. In 2007 (the most recent year for which statistics are available), 223,307 men were diagnosed with prostate cancer, and 29,093 men died from it.


Different people have different symptoms for prostate cancer. Some men do not have symptoms at all. Some symptoms of prostate cancer are—
  • Difficulty in starting urination.
  • Weak or interrupted flow of urine.
  • Frequent urination, especially at night.
  • Difficulty in emptying the bladder completely.
  • Pain or burning during urination.
  • Blood in the urine or semen.
  • Pain in the back, hips, or pelvis that doesn't go away.
  • Painful ejaculation.
If you have any symptoms that worry you, be sure to see your doctor right away. These symptoms may be caused by conditions other than prostate cancer.

Risk Factors

There is no way to know for sure if you will get prostate cancer. Men have a greater chance of getting prostate cancer if they are 50 years old or older, are African-American, or have a father, brother, or son who has had prostate cancer.

Screening for Prostate Cancer

Not all medical experts agree that screening for prostate cancer will save lives. Currently, there is not enough credible evidence to decide if the potential benefit of prostate cancer screening outweighs the potential risks. The potential benefit of prostate cancer screening is early detection of cancer, which may make treatment more effective. Potential risks include false positive test results (the test says you have cancer when you do not), treatment of prostate cancers that may never affect your health, and mild to serious side effects from treatment of prostate cancer.
Most organizations recommend that men discuss with their doctors the benefits and risks of prostate cancer screening. CDC supports informed decision making, which encourages men to talk with their doctors to learn the nature and risk of prostate cancer, understand the benefits and risks of the screening tests, and make decisions consistent with their preferences and values.
Tests that are commonly used to screen for prostate cancer are—
  • Digital rectal exam (DRE): A doctor, nurse, or other health care professional places a gloved finger into the rectum to feel the size, shape, and hardness of the prostate gland.
  • Prostate specific antigen test (PSA): PSA is a substance made by the prostate. The PSA test measures the level of PSA in the blood, which may be higher in men who have prostate cancer. However, other conditions such as an enlarged prostate, prostate infections, and certain medical procedures also may increase PSA levels.

Lesson 5: Communicable (Infectious) Diseases

Communicable (Infectious) Diseases


Source: NIH: National Institute of Allergy and Infectious Diseases, MedlinePlus,
Infectious diseases kill more people worldwide than any other single cause. Infectious diseases are caused by germs. Germs are tiny living things that are found everywhere - in air, soil and water. You can get infected by touching germs.
There are four main kinds of germs:
  • Bacteria - one-celled germs that multiply quickly and may release chemicals which can make you sick
  • Viruses - capsules that contain genetic material, and use your own cells to multiply
  • Fungi - primitive vegetables, like mushrooms or mildew
  • Protozoa - one-celled animals that use other living things for food and a place to live

Learning Activity 5.1: Watch this video about Infectious Diseases Then and Now


Bacteria are living things that have only one cell. Under a microscope, they look like balls, rods or spirals. They are so small that a line of 1,000 could fit across a pencil eraser. Most bacteria won't hurt you - less than 1 percent makes people sick. Many are helpful. Some bacteria help to digest food, destroy disease-causing cells and give the body needed vitamins. Bacteria are also used in making healthy foods like yogurt and cheese.
But infectious bacteria can make you ill. They reproduce quickly in your body. Many give off chemicals called toxins, which can damage tissue and make you sick. Examples of bacteria that cause infections include Streptococcus, Staphylococcus, and E. coli.
Antibiotics are the usual treatment. When you take antibiotics, follow the directions carefully. Each time you take antibiotics, you increase the chances that bacteria in your body will learn to resist them. Later, you could get or spread an infection that those antibiotics cannot cure.

Strep Throat

Source: NIH: National Institute of Allergy and Infectious Diseases via

Streptococcal infections (strep for short) cause a variety of health problems. There are two types: group A and group B. Antibiotics are used to treat both.
Group A strep causes -

  • Strep throat - a sore, red throat, sometimes with white spots on the tonsils
  • Scarlet fever - red rash on the body
  • Impetigo - a skin infection
  • Toxic shock syndrome
  • Cellulitis and necrotizing fasciitis (flesh-eating disease)
Group B strep can cause blood infections, pneumonia and meningitis in newborns. A screening test during pregnancy can tell if you have it. If you do, I.V. antibiotics during labor can save your baby's life. Adults can also get group B strep infections, especially if they are elderly or already have health problems. Strep B can cause urinary tract infections, blood infections, skin infections and pneumonia in adults.

Tuberculosis (TB)

In developed countries, such as the United States, many people think TB is a disease of the past. TB, however, is still a leading killer of young adults worldwide. Some 2 billion people—one-third of the world's population—are thought to be infected with TB bacteria, Mycobacterium tuberculosis (Mtb).
TB is a chronic bacterial infection. It is spread through the air and usually infects the lungs, although other organs and parts of the body can be involved as well. Most people who are infected with Mtb harbor the bacterium without symptoms (have latent TB), but some will develop active TB disease. According to World Health Organization estimates, each year 8 million people worldwide develop active TB and nearly 2 million die.
One in 10 people who are infected with Mtb may develop active TB at some time in their lives. The risk of developing active disease is greatest in the first year after infection, but active disease often does not occur until many years later.

TB in the United States

In 2006, the Centers for Disease Control and Prevention (CDC) reported 13,799 cases of active TB. While the overall rate of new TB cases continues to decline in the United States since national reporting began in 1953, the annual decrease in TB cases has slowed from an average of 7.1 percent (1993–2000) to the current average of 3.8 percent (2001–2005), according to CDC. In addition to those with active TB, an estimated 10 to 15 million people in the United States have latent TB.
Minorities are affected disproportionately by TB, which occurs among foreign-born individuals nearly nine times as frequently as among people born in the United States. This is partially because they were often exposed to Mtb in their country of origin before moving to the United States. In 2004, a very high percentage of Asians (95 percent) and Hispanics (75 percent) who were born outside the United States were reported to have TB.
Tuberculosis (TB) is a bacterial infection caused by a germ called Mycobacterium tuberculosis. The bacteria usually attack the lungs, but they can also damage other parts of the body. TB spreads through the air when a person with TB of the lungs or throat coughs, sneezes or talks. If you have been exposed, you should go to your doctor for tests. You are more likely to get TB if you have a weak immune system.
Symptoms of TB in the lungs may include-
  • A bad cough that lasts 3 weeks or longer
  • Weight loss
  • Coughing up blood or mucus
  • Weakness or fatigue
  • Fever and chills
  • Night sweats
If not treated properly, TB can be deadly. You can usually cure active TB by taking several medicines for a long period of time. People with latent TB can take medicine so that they do not develop active TB.

Viral Infections

Source: NLM, NIH via

Viruses are capsules with genetic material inside. They are very tiny, much smaller than bacteria. Viruses cause familiar infectious diseases such as the common cold, flu and warts. They also cause severe illnesses such as HIV/AIDS, smallpox and hemorrhagic fevers.
Viruses are like hijackers. They invade living, normal cells and use those cells to multiply and produce other viruses like themselves. This eventually kills the cells, which can make you sick.
Viral infections are hard to treat because viruses live inside your body's cells. They are "protected" from medicines, which usually move through your bloodstream. Antibiotics do not work for viral infections. There are a few antiviral medicines available. Vaccines can help prevent you from getting many viral diseases.


Source: NIH: National Institute of Allergy and Infectious Diseases via

Flu is a respiratory infection caused by a number of viruses. The viruses pass through the air and enter your body through your nose or mouth. Between 5% and 20% of people in the U.S. get the flu each year. The flu can be serious or even deadly for elderly people, newborn babies and people with certain chronic illnesses.
Symptoms of the flu come on suddenly and are worse than those of the common cold. They may include-
  • Body or muscle aches
  • Chills
  • Cough
  • Fever
  • Headache
  • Sore throat
Is it a cold or the flu? Colds rarely cause a fever or headaches. Flu almost never causes an upset stomach. And "stomach flu" isn't really flu at all, but gastroenteritis.
The main way to keep from getting the flu is to get a yearly flu vaccine. If you get the flu, your health care provider may prescribe medicine to help your body fight the infection and lessen symptoms.

Learning Activity 5.3: Watch these videos -

Common Cold

Sneezing, sore throat, a stuffy nose, coughing - everyone knows the symptoms of the common cold. It is probably the most common illness. In the course of a year, people in the United States suffer 1 billion colds.
You can get a cold by touching your eyes or nose after you touch surfaces with cold germs on them. You can also inhale the germs. Symptoms usually begin 2 or 3 days after infection and last 2 to 14 days. Washing your hands and staying away from people with colds will help you avoid colds.However, do not give aspirin to children. And do not give cough medicine to children under four.
There is no cure for the common cold. For relief, try
  • Getting plenty of rest
  • Drinking fluids
  • Gargling with warm salt water
  • Using cough drops or throat sprays
  • Taking over-the-counter pain or cold medicines

Hepatitis B

Source: NIH: National Institute of Diabetes and Digestive and Kidney Diseases via
Hepatitis B is one type of hepatitis - a liver disease- caused by the hepatitis B virus (HBV). Hepatitis B spreads by contact with an infected person's blood, semen or other body fluid. An infected woman can give hepatitis B to her baby at birth.
If you get HBV, you may feel as if you have the flu, or you may have no symptoms at all. A blood test can tell if you have it. HBV usually gets better on its own after a few months. If it does not get better, it is called chronic HBV, which lasts a lifetime. Chronic HBV can lead to scarring of the liver, liver failure or liver cancer.
There is a vaccine for HBV. It requires three shots. All babies should get the vaccine, but older children and adults can get it too. If you travel to countries where Hepatitis B is common, you should get the vaccine.

Learning Activity 5.4:

Are you at risk for viral hepatitis? Take this quick Hepatitis Risk Assessment test to find out.

Infectious mononucleosis

Infectious mononucleosis, or "mono", is an infection caused by the Epstein-Barr virus. The virus spreads through saliva, which is why it's sometimes called "kissing disease." Mono occurs most often in 15 to 17-year-olds. However, you can get it at any age. Symptoms of mono include
  • Fever
  • Sore throat
  • Swollen lymph glands
Sometimes you may also have a swollen spleen. Serious problems are rare.
A blood test can show if you have mono. Most people get better in two to four weeks. However, you may feel tired for a few months afterward. Treatment focuses on helping symptoms and includes medicines for pain and fever, warm salt water gargles and plenty of rest and fluids.



If you have ever had athlete's foot or a yeast infection, you can blame a fungus. A fungus is actually a primitive vegetable. Mushrooms, mold and mildew are examples. Fungi live in air, in soil, on plants and in water. Some live in the human body. Only about half of all types of fungi are harmful.
Some fungi reproduce through tiny spores in the air. You can inhale the spores or they can land on you. As a result, fungal infections often start in the lungs or on the skin. You are more likely to get a fungal infection if you have a weakened immune system or take antibiotics.
Fungi can be difficult to kill. For skin and nail infections, you can apply medicine directly to the infected area. Oral antifungal medicines are also available for serious infections.

Yeast Infections (or Candida)


Candida is the scientific name for yeast. It is a fungus that lives almost everywhere, including in your body. Usually, your immune system keeps yeast under control. If you are sick or taking antibiotics, it can multiply and cause an infection.
Yeast infections affect different parts of the body in different ways:
  • Thrush is a yeast infection that causes white patches in your mouth
  • Esophagitis is thrush that spreads to your esophagus, the tube that takes food from your mouth to your stomach. Esophagitis can make it hard or painful to swallow
  • Women can get vaginal yeast infections, causing itchiness, pain and discharge
  • Yeast infections of the skin cause itching and rashes
  • Yeast infections in your bloodstream can be life-threatening
Antifungal medicines eliminate yeast infections in most people. If you have a weak immune system, treatment might be more difficult.

Parasitic Diseases

Source: National Library of Medicine, National Institutes for Health via

Parasites are living things that use other living things - like your body - for food and a place to live. You can get them from contaminated food or water, a bug bite, or sexual contact. Parasitic diseases can cause mild discomfort or be deadly.
Parasites range in size from tiny, one-celled organisms called protozoa to worms that can be seen with the naked eye. Some parasitic diseases happen in the United States. Contaminated water supplies can lead to Giardia infections. Cats can transmit toxoplasmosis, which is dangerous for pregnant women. Others, like malaria, are common in other parts of the world.
If you are traveling, it's important to drink only water you know is safe. Prevention is especially important. There are no vaccines for parasitic diseases. Some medicines are available to treat parasitic infections.



Pneumonia is an inflammation of the lung, usually caused by an infection. Three common causes are bacteria, viruses and fungi. You can also get pneumonia by accidentally inhaling a liquid or chemical. People most at risk are older than 65 or younger than 2 years of age, or already have health problems.
If you have pneumonia, you may have difficulty breathing and have a cough and a fever. A physical exam and history can help determine if you have pneumonia. Chest x-rays and blood tests can help determine what is wrong. Treatment depends on what made you sick. If bacteria are the cause, antibiotics should help. Viral pneumonia may get better with rest and drinking liquids.
Preventing pneumonia is always better than treating it. The best preventive measures include washing your hands frequently, not smoking, and wearing a mask when cleaning dusty or moldy areas. There is a vaccine for pneumococcal pneumonia, a bacterial infection which accounts for up to a quarter of all pneumonias.

Defining Health Disparities

Source: Centers for Disease Control and Prevention,

Despite prevention efforts, some groups of people are affected by HIV/AIDS, viral hepatitis, STDs, and TB more than other groups of people. The occurrence of these diseases at greater levels among certain population groups more than among others is often referred to as a health disparity. Differences may occur by gender, race or ethnicity, education, income, disability, geographic location and sexual orientation among others. Social determinants of health like poverty, unequal access to health care, lack of education, stigma, and racism are linked to health disparities.

Optional: For more information on this topic, see or listen to: What You Need to Know About Infectious Diseases.

Lesson 6: Immunity and Immunizations


Source: OpenStax College, Introduction to Health and Medicine, Connexions, May 18, 2012.

In 2010, a pertussis (whooping cough) outbreak in California sickened 9,143 people and resulted in 10 infant deaths: the worst outbreak in 63 years (Centers for Disease Control 2011b). Researchers, suspecting that the primary cause of the outbreak was the waning strength of pertussis vaccines in older children, recommended a booster vaccination for 11–12-year-olds and also for pregnant women (Zacharyczuk 2011). Pertussis is most serious for babies; one in five needs to be hospitalized, and since they are too young for the vaccine themselves, it is crucial that people around them be immunized (Centers for Disease Control 2011b). Several states, including California, have been requiring the pertussis booster for older children in recent years with the hope of staving off another outbreak.

But what of people who do not want their children to have this vaccine, or any other? That question is at the heart of a debate that has been simmering for years. Vaccines are biological preparations that improve immunity against a certain disease. Vaccines have contributed to the eradication and weakening of numerous infectious diseases, including smallpox, polio, mumps, chicken pox, and meningitis.

However, many people express concern about potential negative side effects from vaccines. These concerns range from fears about overloading the child’s immune system to controversial reports about devastating side effects of the vaccines. One misapprehension is that the vaccine itself might cause the disease it is supposed to be immunizing against.

Another commonly circulated concern is that vaccinations, specifically the MMR vaccine (MMR stands for measles, mumps, and rubella), are linked to autism. The autism connection has been particularly controversial. In 1998, a British physician named Andrew Wakefield published a study in Great Britain’s Lancet magazine that linked the MMR vaccine to autism. The report received a lot of media attention, resulting in British immunization rates decreasing from 91 percent in 1997 to almost 80 percent by 2003, accompanied by a subsequent rise in measles cases (Devlin 2008). A prolonged investigation by the British Medical Journal proved that not only was the link in the study nonexistent, but that Dr. Wakefield had falsified data in order to support his claims (CNN 2011). Dr. Wakefield was discredited and stripped of his license, but the doubt still lingers in many parents’ minds.

In the United States, many parents still believe in the now discredited MMR-autism link and refuse to vaccinate their children. Other parents choose not to vaccinate for various reasons like religious or health beliefs. In one instance, a boy whose parents opted not to vaccinate returned home to the U.S. after a trip abroad; no one yet knew he was infected with measles. The boy exposed 839 people to the disease and caused 11 additional cases of measles, all in other unvaccinated children, including one infant who had to be hospitalized. According to a study published in Pediatrics (2010), the outbreak cost the public sector $10,376 per diagnosed case. The study further showed that the intentional non-vaccination of those infected occurred in students from private schools, public charter schools, and public schools in upper-socioeconomic areas (Sugerman et al. 2010).
Consider these questions about immunization:

  • Should parents be forced to immunize their children?
  • How does this story of vaccines in a high-income region compare to that in a low-income region, like sub-Saharan Africa, where populations are often eagerly seeking vaccines rather than refusing them?
  • Do you believe all children should receive vaccinations?

Immunity and Immunizations

Source: National Institute of Allergy and Infectious Diseases via

Shots may hurt a little... but the diseases they can prevent can hurt a lot more! Immunization shots, or vaccinations, are essential. They protect against things like measles, mumps, rubella, hepatitis B, polio, diphtheria, tetanus and pertussis (whooping cough). Immunizations are important for adults as well as for children. Here's why.
Your immune system helps your body fight germs by producing substances to combat them. Once it does, the immune system "remembers" the germ and can fight it again. Vaccines contain germs that have been killed or weakened. When given to a healthy person, the vaccine triggers the immune system to respond and thus build immunity.
Before vaccines, people became immune only by actually getting a disease and surviving it. Immunizations are an easier and less risky way to become immune.

Optional Learning Activity: Take action to raise awareness of immunizations (e.g., Assist a school nurse to host an immunization education event for parents at a local school)


Source: Vaccines, US Dept. of Health and Human Services,

Vaccines are the best defense we have against serious, preventable, and sometimes deadly contagious diseases. Vaccines are some of the safest medical products available, but like any other medical product, there may be risks. Accurate information about the value of vaccines as well as their possible side-effects helps people to make informed decisions about vaccination.
Federal law requires that Vaccine Information Statements explaining vaccine benefits and risks be handed out whenever (before each dose) certain vaccinations are given. Vaccine Information Statements are available in Spanish and many different languages. In addition, more detailed information describing the benefits and risks of a particular vaccine is available in the Prescribing Information from the Food and Drug Administration.
The following sections answer common questions asked about vaccines and how vaccines are tested and monitored to ensure they are safe and effective. These sections are currently available in English only.
Vaccines are held to the highest standard of safety. The United States currently has the safest, most effective vaccine supply in history. Vaccines undergo a rigorous and extensive evaluation program to determine a product’s safety and effectiveness. If a vaccine does receive approval, it is continuously monitored for safety and effectiveness.
Many partners work together to make sure vaccines are safe. Government health scientists work with manufacturers, health care providers, academia, and global health groups such as the World Health Organization to build a comprehensive vaccine safety system. At the Department of Health and Human Services, primarily three agencies work on vaccine safety:
  • Centers for Disease Control and Prevention (CDC)
  • National Institutes of Health (NIH)
  • Food and Drug Administration (FDA)
Vaccines undergo rigorous and extensive testing to determine their safety and effectiveness prior to approval. Following approval, FDA carefully monitors the quality of vaccines—all manufactured lots must pass tests before they can be used. Vaccine manufacturers also must follow strict manufacturing standards, and FDA conducts routine inspections of manufacturing sites.
Scientists from FDA and CDC work closely to monitor reports of vaccine side effects (adverse events) after they are approved and used widely. FDA and CDC take all reports seriously, and work together to evaluate and address any potential problems.

Learning Activity 4.1: Watch this video titled Get The Picture: Childhood Immunizations
(6:27 minutes)
Source: //National Center for Immunization and Respiratory Diseases//

After talking with parents across the country, CDC put together this short video to help answer the tough questions that real moms had about childhood immunizations.

Understanding the importance of vaccines is crucial for you to protect your children’s health. Read the script
  • Did watching this video help you decide on whether or not to get your child immunized?
  • Interview some parents to find out what they think about this issue.

Potential Side Effects

Vaccines, like all medical products, may cause side effects in some people. Most of these side effects are minor, such as redness or swelling at the injection site. Read further to learn about possible side effects from vaccines.
Any vaccine can cause side effects. For the most part these are minor (for example, a sore arm or low-grade fever) and go away within a few days.
Remember, vaccines are continually monitored for safety, and like any medication, vaccines can cause side effects. However, a decision not to immunize a child also involves risk and could put the child and others who come into contact with him or her at risk of contracting a potentially deadly disease.

How Well Do Vaccines Work?

Vaccines work really well. No medicine is perfect, of course, but most childhood vaccines produce immunity about 90 - 100% of the time.
What about the argument made by some people that vaccines don’t work that well . . . that diseases would be going away on their own because of better hygiene or sanitation, even if there were no vaccines?
That simply isn’t true. Certainly better hygiene and sanitation can help prevent the spread of disease, but the germs that cause disease will still be around, and as long as they are they will continue to make people sick.
All vaccines must be licensed (approved) by the Food and Drug Administration (FDA) before being used in the United States, and a vaccine must go through extensive testing to show that it works and that it is safe before the FDA will approve it. Among these tests are clinical trials, which compare groups of people who get a vaccine with groups of people who get a control. A vaccine is approved only if FDA makes the determination that it is safe and effective for its intended use.
If you look at the history of any vaccine-preventable disease, you will virtually always see that the number of cases of disease starts to drop when a vaccine is licensed. Vaccines are the most effective tool we have to prevent infectious diseases.


Vaccines help the body’s immune system prepare for future attacks. Vaccines consist of killed or modified microbes, parts of microbes, or microbial DNA that trick the body into thinking an infection has occurred. A vaccinated person’s immune system attacks the harmless vaccine and prepares for invasions against the kind of microbe the vaccine contained. In this way, the person becomes immunized against the microbe: if re-exposure to the infectious microbe occurs, the immune system will quickly recognize how to stop the infection.
This section explains more in detail about how your immune system works to prevent you from getting sick. Knowing how your immune system works may help you understand how vaccines work with your immune system to protect you.

What is the Immune System?

The immune system is a network of cells, tissues, and organs that work together to defend the body against attacks by “foreign” invaders. These are primarily microbes—tiny organisms such as bacteria, parasites, and fungi that can cause infections. Viruses also cause infections, but are too primitive to be classified as living organisms. The human body provides an ideal environment for many microbes. It is the immune system’s job to keep them out or, failing that, to seek out and destroy them.
When the immune system hits the wrong target, however, it can unleash a torrent of disorders, including allergic diseases, arthritis, and a form of diabetes. If the immune system is crippled, other kinds of diseases result.
The immune system is amazingly complex. It can recognize and remember millions of different enemies, and it can produce secretions (release of fluids) and cells to match up with and wipe out nearly all of them.
The secret to its success is an elaborate and dynamic communications network. Millions and millions of cells, organized into sets and subsets, gather like clouds of bees swarming around a hive and pass information back and forth in response to an infection. Once immune cells receive the alarm, they become activated and begin to produce powerful chemicals. These substances allow the cells to regulate their own growth and behavior, enlist other immune cells, and direct the new recruits to trouble spots.
In addition, scientists are rapidly unraveling the genetic blueprints that direct the human immune response, as well as those that dictate the biology of bacteria, viruses, and parasites. The combination of new technology and expanded genetic information will no doubt reveal even more about how the body protects itself from disease.

Mounting an Immune Response

Infections are the most common cause of human disease. They range from the common cold to debilitating conditions like chronic hepatitis to life-threatening diseases such as AIDS. Disease-causing microbes (pathogens) attempting to get into the body must first move past the body’s external armor, usually the skin or cells lining the body’s internal passageways.
The skin provides an imposing barrier to invading microbes. It is generally penetrable only through cuts or tiny abrasions. The digestive and respiratory tracts—both portals of entry for a number of microbes—also have their own levels of protection. Microbes entering the nose often cause the nasal surfaces to secrete more protective mucus, and attempts to enter the nose or lungs can trigger a sneeze or cough reflex to force microbial invaders out of the respiratory passageways. The stomach contains a strong acid that destroys many pathogens that are swallowed with food.
If microbes survive the body’s front-line defenses, they still have to find a way through the walls of the digestive, respiratory, or urogenital passageways to the underlying cells. These passageways are lined with tightly packed epithelial cells covered in a layer of mucus, effectively blocking the transport of many pathogens into deeper cell layers.
Mucosal surfaces also secrete a special class of antibody called IgA, which in many cases is the first type of antibody to encounter an invading microbe. Underneath the epithelial layer a variety of immune cells, including macrophages, B cells, and T cells, lie in wait for any microbe that might bypass the barriers at the surface.
Next, invaders must escape a series of general defenses of the innate immune system, which are ready to attack without regard for specific antigen markers. These include patrolling phagocytes, natural killer T cells, and complement.
Microbes cross the general barriers then confront specific weapons of the adaptive immune system tailored just for them. These specific weapons, which include both antibodies and T cells, are equipped with singular receptor structures that allow them to recognize and interact with their designated targets.


Long ago, physicians realized that people who had recovered from the plague would never get it again—they had acquired immunity. This is because some of the activated T and B cells had become memory cells. Memory cells ensure that the next time a person meets up with the same antigen, the immune system is already set to demolish it.
Immunity can be strong or weak, short-lived or long-lasting, depending on the type of antigen it encounters, the amount of antigen, and the route by which the antigen enters the body. Immunity can also be influenced by inherited genes. When faced with the same antigen, some individuals will respond forcefully, others feebly, and some not at all.
An immune response can be sparked not only by infection but also by immunization with vaccines. Some vaccines contain microorganisms—or parts of microorganisms— that have been treated so they can provoke an immune response but not full-blown disease.
Immunity can also be transferred from one individual to another by injections of serum rich in antibodies against a particular microbe (antiserum). For example, antiserum is sometimes given to protect travelers to countries where hepatitis A is widespread. The antiserum induces passive immunity against the hepatitis A virus. Passive immunity typically lasts only a few weeks or months.


Source: National Institute of Allergy Infectious Diseases

For many years, healthcare providers have used vaccination to help the body’s immune system prepare for future attacks. Vaccines consist of killed or modified microbes, parts of microbes, or microbial DNA that trick the body into thinking an infection has occurred.
A vaccinated person’s immune system attacks the harmless vaccine and prepares for invasions against the kind of microbe the vaccine contained. In this way, the person becomes immunized against the microbe. Vaccination remains one of the best ways to prevent infectious diseases, and vaccines have an excellent safety record. Previously devastating diseases such as smallpox, polio, and whooping cough (pertussis) have been greatly controlled or eliminated through worldwide vaccination programs.

Recommended Vaccines for Young Adults

Source: College, CDC,

The transition to adulthood is an exciting time in a young person’s life. Starting a career, getting an apartment, entering college, or joining the armed forces all offer unique rewards and challenges.
Yet young adults may not know that some vaccines can make this transitional time a healthier one.
Vaccines recommended for young adults ages 19–24 include:
  • Meningococcal conjugate vaccine, which helps prevent meningococcal disease
  • Tdap vaccine, which protects against tetanus, diphtheria, and pertussis (also known as whooping cough)
  • HPV vaccine, which protects against the viruses that cause most cervical cancers, anal cancer, and genital warts
  • Seasonal flu vaccine
There may be other vaccines recommended for young adults because their health, job, or lifestyle may put them at higher risk for certain diseases. Young adults should talk to a doctor or nurse to find out if there are other vaccines that they may need.

Learning Activity 4.2: Take this quiz to find out to find out which vaccines YOU may need.

Antibiotic / Antimicrobial Resistance

Source: Antiicrobal Resistance, CDC,

Antibiotics and similar drugs, together called antimicrobial agents, have been used for the last 70 years to treat patients who have infectious diseases. Since the 1940s, these drugs have greatly reduced illness and death from infectious diseases. Antibiotic use has been beneficial and, when prescribed and taken correctly, their value in patient care is enormous.

However, these drugs have been used so widely and for so long that the infectious organisms the antibiotics are designed to kill have adapted to them, making the drugs less effective. People infected with antimicrobial-resistant organisms are more likely to have longer, more expensive hospital stays, and may be more likely to die as a result of the infection.

Optional: Heart Health

Instructions: Quick Guide to Healthy Living: Click on at least 5 topics to explore from this list of links. Be prepared to justify your selections and describe what you learned.
Heart Disease

Optional: Cancer Screening and Prevention

Instructions: Quick Guide to Healthy Living: Click on at least 5 topics to explore from this list of links. Be prepared to justify your selections and describe what you learned.
Cancer Screening and Prevention

Optional: Diabetes

Instructions: Quick Guide to Healthy Living: Click on at least 5 topics to explore from this list of links. Be prepared to justify your selections and describe what you learned.

Optional: Sexually Transmitted Diseases and HIV

Sexually Transmitted Diseases

Source: Sexually Transmitted Diseases, Centers for Disease Control and Prevention via MedlinePlus,

Sexually transmitted diseases (STDs) are infections that you can get from having sex with someone who has the infection. The causes of STDs are bacteria, viruses, and parasites. There are more than 20 types of STDs, including:
  • Bacterial
    • Gonorrhea
  • Viral
    • Genital herpes
    • HIV/AIDS
    • HPV
    • Syphilis
  • Parasitic
    • Trichomoniasis
Most STDs affect both men and women, but in many cases the health problems they cause can be more severe for women. If a pregnant woman has an STD, it can cause serious health problems for the baby.
If you have an STD caused by bacteria or parasites, your health care provider can treat it with antibiotics or other medicines. If you have an STD caused by a virus, there is no cure. Sometimes medicines can keep the disease under control. Correct usage of latex condoms greatly reduces, but does not completely eliminate, the risk of catching or spreading STDs.


Source: Gonorrhea, Centers for Disease Control and Prevention via MedlinePlus,

Gonorrhea is a curable sexually transmitted disease. It is most common in young adults. The bacteria that cause gonorrhea can infect the genital tract, mouth or anus.
Gonorrhea does not always cause symptoms, especially in women. In men, gonorrhea can cause pain when urinating and discharge from the penis. If untreated, it can cause epididymitis, which affects the testicles and can lead to infertility. In women, gonorrhea can cause bleeding between periods, pain when urinating and increased discharge from the vagina. If untreated, it can lead to pelvic inflammatory disease, which causes problems with pregnancy and infertility. Gonorrhea can pass from mother to baby during pregnancy.
You can cure gonorrhea with antibiotics prescribed by your health care provider. Correct usage of latex condoms greatly reduces, but does not eliminate, the risk of catching or spreading gonorrhea.

Genital Herpes

Source: Genital Herpes, Medline, NLM, NIH,

Genital herpes is a sexually transmitted disease (STD) caused by a herpes simplex virus (HSV). It can cause sores on your genital or rectal area, buttocks, and thighs. You can get it from having sex, even oral sex. The virus can spread even when sores are not present. Mothers can also infect their babies during childbirth.
Symptoms of herpes are called outbreaks. You usually get sores near the area where the virus has entered the body. They turn into blisters, become itchy and painful, and then heal. Sometimes people do not know they have herpes because they have no symptoms or very mild symptoms. The virus can be more serious in newborn babies or in people with weak immune systems.
Most people have outbreaks several times a year. Over time, you get them less often and the symptoms become milder. The virus stays in your body for life.
Medicines do not cure genital herpes, but they can to help your body fight the virus. This can help lessen symptoms, decrease outbreaks, and lower the risk of passing the virus to others. Correct usage of latex condoms can reduce, but not eliminate, the risk of catching or spreading herpes.

Learning Activity 5.1: Watch this video about Molly's story and herpes. (Transcript)
Source: National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention (NCHHSTP)

HPV (or genital warts)

Source: HPV, NLM, NIH,

Human papillomaviruses (HPV) are common viruses that can cause warts. There are more than 100 types of HPV. Most are harmless, but about 30 types put you at risk for cancer. These types affect the genitals and you get them through sexual contact with an infected partner. They are classified as either low-risk or high-risk. Low-risk HPV can cause genital warts. High-risk HPV can lead to cancers of the cervix, vulva, vagina, and anus in women. In men, it can lead to cancers of the anus and penis.
Although some people develop genital warts from HPV infection, others have no symptoms. Your health care provider can treat or remove the warts. In women, Pap smears can detect changes in the cervix that might lead to cancer.
Correct usage of latex condoms greatly reduces, but does not eliminate, the risk of catching or spreading HPV. A vaccine can protect against several types of HPV, including some that can cause cancer.


Source: Trichomoniasis, NLM, NIH,

Trichomoniasis is a sexually transmitted disease caused by a parasite. It affects both women and men, but symptoms are more common in women. Symptoms in women include a green or yellow discharge from the vagina, itching in or near the vagina and discomfort with urination. Most men with trichomoniasis don't have any symptoms, but it can cause irritation inside the penis.
You can cure trichomoniasis with antibiotics. In men, the infection usually goes away on its own without causing symptoms. But an infected man can continue to infect or reinfect a woman until he gets treated. So it's important that both partners get treated at the same time. Correct usage of latex condoms greatly reduces, but does not eliminate, the risk of catching or spreading trichomoniasis.


Source: AIDS and HIV, NIAID, NIH,

AIDS was first reported in the United States in 1981 and has since become a major worldwide epidemic. AIDS is caused by the human immunodeficiency virus, or HIV. By killing or damaging cells of the body's immune system, HIV progressively destroys the body's ability to fight infections and certain cancers. People diagnosed with AIDS may get life-threatening diseases called opportunistic infections. These infections are caused by microbes such as viruses or bacteria that usually do not make healthy people sick.
Since 1981, more than 980,000 cases of AIDS have been reported in the United States to the Centers for Disease Control and Prevention (CDC). According to CDC, more than 1,000,000 Americans may be infected with HIV, one-quarter of whom are unaware of their infection. The epidemic is growing most rapidly among minority populations and is a leading killer of African-American males ages 25 to 44. According to CDC, AIDS affects nearly seven times more African Americans and three times more Hispanics than whites. In recent years, an increasing number of African-American women and children are being affected by HIV/AIDS.

  • The U.S. HIV/AIDS epidemic began in 1981 and continues to disproportionately affect minorities, men who have sex with men of all races, women, and youth.
  • More than 1 million people in the United States currently are living with HIV/AIDS.
  • About 21 percent of those infected with HIV are unaware of their infection.
  • Since the U.S. epidemic began, 617,025 people have died of AIDS.
  • In 2008, there were approximately 42,439 new HIV infections, with the highest proportion among African Americans despite the fact that they make up only 12 percent of the U.S. population.


Source: HIV, National Library of Medicine, National Institutes for Health,

HIV stands for human immunodeficiency virus. It kills or damages the body's immune system cells. AIDS stands for acquired immunodeficiency syndrome. It is the most advanced stage of infection with HIV.
HIV most often spreads through unprotected sex with an infected person. It may also spread by sharing drug needles or through contact with the blood of an infected person. Women can give it to their babies during pregnancy or childbirth.
The first signs of HIV infection may be swollen glands and flu-like symptoms. These may come and go a month or two after infection. Severe symptoms may not appear until months or years later.
A blood test can tell if you have HIV infection. Your health care provider can perform the test.
There is no cure, but there are many medicines to fight both HIV infection and the infections and cancers that come with it. People can live with the disease for many years.

AIDS Prevention

Cause: AIDS Prevention, NIAID, NIH,

Currently, there is no vaccine to prevent HIV infection nor is there a cure for HIV/AIDS. To reduce your risk of becoming infected with HIV or transmitting the virus to others
  • Get tested regularly for HIV
  • Practice abstinence
  • Remain faithful to your spouse or partner
  • Consistently use male latex or female polyurethane condoms
  • Do not share needles

Detection and Treatment in HIV Prevention

Source: Role Detection and Treatment in HIV Prevention, CDC,

Testing and treatment of sexually transmitted diseases (STDs) can be an effective tool in preventing the spread of HIV, the virus that causes AIDS. An understanding of the relationship between STDs and HIV infection can help in the development of effective HIV prevention programs for persons with high-risk sexual behaviors.

What is the link between STDs and HIV infection?

Individuals who are infected with STDs are at least two to five times more likely than uninfected individuals to acquire HIV infection if they are exposed to the virus through sexual contact. In addition, if an HIV-infected individual is also infected with another STD, that person is more likely to transmit HIV through sexual contact than other HIV-infected persons (Wasserheit, 1992).
There is substantial biological evidence demonstrating that the presence of other STDs increases the likelihood of both transmitting and acquiring HIV.
  • Increased susceptibility. STDs appear to increase susceptibility to HIV infection by two mechanisms. Genital ulcers (e.g., syphilis, herpes, or chancroid) result in breaks in the genital tract lining or skin. These breaks create a portal of entry for HIV. Additionally, inflammation resulting from genital ulcers or non-ulcerative STDs (e.g., chlamydia, gonorrhea, and trichomoniasis) increase the concentration of cells in genital secretions that can serve as targets for HIV (e.g., CD4+ cells).
*Increased infectiousness. STDs also appear to increase the risk of an HIV-infected person transmitting the virus to his or her sex partners. Studies have shown that HIV-infected individuals who are also infected with other STDs are particularly likely to shed HIV in their genital secretions. For example, men who are infected with both gonorrhea and HIV are more than twice as likely to have HIV in their genital secretions than are those who are infected only with HIV. Moreover, the median concentration of HIV in semen is as much as 10 times higher in men who are infected with both gonorrhea and HIV than in men infected only with HIV. The higher the concentration of HIV in semen or genital fluids, the more likely it is that HIV will be transmitted to a sex partner.

How can STD treatment slow the spread of HIV infection?

Evidence from intervention studies indicates that detecting and treating STDs may reduce HIV transmission.
  • STD treatment reduces an individual's ability to transmit HIV. Studies have shown that treating STDs in HIV-infected individuals decreases both the amount of HIV in genital secretions and how frequently HIV is found in those secretions (Fleming, Wasserheit, 1999).
  • Herpes can make people more susceptible to HIV infection, and it can make HIV-infected individuals more infectious. It is critical that all individuals, especially those with herpes, know whether they are infected with HIV and, if uninfected with HIV, take measures to protect themselves from infection with HIV.
  • Among individuals with both herpes and HIV, trials are underway studying if treatment of the genital herpes helps prevent HIV transmission to partners.

Learning Activity 5.2: Watch this video about AIDS:

Optional: Osteoporosis Risk Awareness Test

Osteoporosis Risk Awareness

Optional: Cancer Risk Activity

Copyright (c) 2012, Siteman Cancer Center at Barnes-Jewish Hospital and Washington University School of Medicine
Instructions: This interactive tool estimates your risk of cancer and provides personalized tips for prevention. Anyone can use it, but it's most accurate for people age 40 and over who have never had any type of cancer. Click on the link below.
Cancer Risk Activity

Optional: Historical Causes of Death

Copyright (c) 2012, Sociological Images CC BY-NC-SA 3.0
Historical Changes in Causes of Death

Optional: Illness, Sickness, and Disease

Illness, Sickness, and Disease

Source: AFMC Primer on Population Health,The Association of Faculties of Medicine of Canada, CC-BY-NC-SA,

Discussing the complexities of what constitutes a disease requires careful distinction among related, but distinct concepts. In 1973, Susser, an epidemiologist, proposed some definitions that remain useful. He used ‘illness’ to refer to the subjective sense of feeling unwell; illness does not define a specific pathology, but refers to a person’s subjective experience of it, such as discomfort, tiredness, or general malaise. The way a patient reports symptoms is influenced by his or her cultural background, and Susser applied the term ‘sickness’ to refer to socially and culturally held conceptions of health conditions (e.g., the dread of cancer or the stigma of mental illness), which in turn influence how the patient reacts ). The social perceptions of disease that Illich described modify the ways a patient perceives and presents his symptoms.

Cultural conventions likewise affect where the boundary between disease and non-disease is placed: menopause may be considered a health issue in North America, but symptoms are far less commonly reported in Japan. Disease implies a focus on pathological processes that may or may not produce symptoms and that result in a patient’s illness. For example, a patient complains of tiredness and malaise–his illness as he experiences it. He consults a doctor about it–because he believes that he might have a sickness. The doctor might attribute the patient’s symptoms to a thyroid condition–a disease.
This model focuses on pathological processes, and on understanding, diagnosing, and treating the physical and biological aspects of disease. The goal of treatment is to restore the patient’s physiological integrity and function. Diagnosis involves recognizing and applying a label to a pattern of signs and symptoms that is at least partly understood in terms of abnormal structure or function of cells, organs, and systems. This offers a rational basis for the investigation of effective treatments. For instance, a certain pattern of chest pain known as angina pectoris is understood biologically as a disorder of the coronary arteries that causes cardiac ischemia, and the treatments it are geared to the specific causes of restoring cardiac blood flow and reducing cardiac effort.
Early biomedical conceptions supposed that a disease is either present or absent: a bacterium has invaded the body or it has not. However, as medicine increasingly tackled conditions, such as hypertension, which represent deviations from normal values, which themselves have a range and can be debated, it became apparent that there may be no set threshold for defining disease. Thus, instead of being seen as a state that is qualitatively distinct from health, many diseases have to be approached as a quantitative threshold on a continuum of biological variability. Organizations such as the World Health Organization (WHO) and the National Institutes of Health have proposed different classifications of hypertension and have changed how they constitute hypertension over time. Hypertension can be mild, moderate or severe, or defined as pre-hypertension or hypertension stage 1 or stage 2.

Optional: Video Lectures about Epidemics

Licensed under Creative Commons 2012, Frank Snowden
Epidemics in Western Society is a course taught Frank Snowden at Yale.
This course consists of video lectures with an international analysis of the impact of epidemic diseases on western society and culture from the bubonic plague to HIV/AIDS and the recent experience of SARS and swine flu.

Leading themes include:
  • infectious disease and its impact on society
  • the development of public health measures
  • the role of medical ethics
  • the genre of plague literature
  • the social reactions of mass hysteria and violence
  • the rise of the germ theory of disease
  • the development of tropical medicine
  • a comparison of the social, cultural, and historical impact of major infectious diseases
  • the issue of emerging and re-emerging diseases

Contemporary Health Issues

Open Courseware

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