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Tools of Prevention

By James T. Pacala, MD, MS, Professor and Associate Head, Department of Family Medicine and Community Health, University of Minnesota Medical School

There are many tools of prevention, including the following major tools:

  • Establishing a healthy lifestyle, which includes habits such as wearing a seat belt, eating a healthy diet, getting enough physical exercise, wearing sunscreen, and not smoking

  • Getting vaccinated to prevent infectious diseases such as influenza, pneumococcal pneumonia, and childhood infections

  • Following recommendations for screening (see Tools of Prevention : Screening) so that disorders such as high blood pressure and cancer are detected early

  • If people are at high risk of developing certain disorders (such as atherosclerosis) or have such a disorder, taking drugs as recommended to prevent the disorder from developing or worsening (preventive drug therapy, also known as chemoprevention)

Preventive drug therapy includes cholesterol-lowering drugs to prevent atherosclerosis, aspirin to prevent heart attacks or strokes, tamoxifen to prevent breast cancer, and antihypertensive drugs to reduce blood pressure and prevent strokes.

Did You Know...

  • Eating a healthy diet, exercising regularly, and stopping smoking help prevent all three leading causes of death in the United States (heart disease, cancer, and stroke).

Healthy Lifestyle

Lifestyle and disease are clearly linked. For example, eating an unhealthy diet (high in calories, saturated fats, and trans fatty acids—see Diet), not exercising regularly, and smoking increase the risk of developing heart disease, cancer, and stroke—the three leading causes of death in the United States. Changing unhealthy lifestyle habits can help prevent particular disorders and/or improve fitness and quality of life. Talking with doctors and other health care practitioners can help people make good decisions and establish healthy habits. However, establishing and maintaining a healthy lifestyle can be done only by the person. Consistently eating a healthy diet and getting enough exercise are difficult for many people, but people who do so reduce their risk of developing serious disorders and often feel better and have more energy.

Healthy eating habits can help people prevent or control disorders such as high blood pressure, heart disease (see Diet), diabetes, osteoporosis, and certain cancers. Recommendations include

  • Eating plenty of vegetables, fruits, and whole-grain cereals and breads, partly because such a diet is high in fiber (see Fiber)

  • Limiting the amount of fat in the diet, for example, by choosing low-fat dairy foods, skinless poultry, and very lean meat

  • Reducing consumption of saturated fats and avoiding trans fatty acids (see Fats) and instead eating foods that contain healthier fats, such as omega-3 acids, present in certain kinds of fish

  • Limiting calories to maintain recommended body weight (see Table: Who Is Overweight?)

  • Limiting the amount of salt consumed

  • Getting enough calcium and vitamin D (in the diet or in supplements)

Physical activity and exercise can help prevent obesity, high blood pressure, heart disease, stroke, diabetes, some types of cancer, constipation, falls, and other health problems. The best routine includes moderate physical activity for 60 minutes or more on all or most days of the week. However, getting even a little bit of exercise is much better than none at all. For example, people who can devote only 10 minutes at a time to physical activity may still reap important benefits, particularly if the exercise is vigorous or if they repeat the activity throughout the day (see Benefits of Exercise). Walking is one simple, effective exercise that many people enjoy. Certain types of exercise can also target specific problems. For example, stretching improves flexibility, which can help prevent falls. Aerobic exercise may decrease the risk of heart attacks and angina.

Quitting smoking is important to a healthful lifestyle. A doctor can offer encouragement and advice on ways to successfully quit smoking, including information and recommendations on the use of nicotine replacement products, bupropion and varenicline (drugs that help reduce cravings), and other tools (see Smoking Cessation: Treatment).

Safe sex practices remain important. Key safe sex practices are avoiding risky sex partners and remaining mutually monogamous. People who have more than one sex partner can greatly reduce their risk of contracting a sexually transmitted disease by correctly using a latex condom every time they have sex (see How to Use a Condom). People who are allergic to latex can use other kinds of condoms.

Limiting alcohol use is important. Although small amounts of alcohol, particularly red wine, may have some health benefits, drinking more than moderate amounts (for example, 1 to 2 drinks per day, possibly less for women) is often harmful (see Alcohol). Each drink is about 12 ounces of beer, 5 ounces of wine, or 1.5 ounces of more concentrated liquor, such as whiskey.

Injury prevention plays a major role in maintaining a healthful lifestyle. People can lower their risk of injury by taking certain precautions.

Adequate sleep is also an important part of a healthy lifestyle, particularly affecting mood and mental state. Insufficient sleep is a risk factor for injuries.


Vaccines have been enormously successful (see Childhood Vaccinations). Dangerous and sometimes fatal infectious diseases such as diphtheria, pertussis, tetanus, mumps, measles, rubella, and polio have decreased by more than 99% from their peak number of cases, thanks to the availability of effective and safe vaccines and their widespread use. Furthermore, vaccinations save about $14 in health care costs for every $1 spent.

Many side effects have been attributed to vaccines. Actual side effects that occur depend on the vaccine, but common side effects are usually minor and include swelling, soreness, allergic reactions at the injection site, and sometimes fever or chills. More serious side effects can occur. They include autoimmune reactions (for example, Guillain-Barré syndrome, which causes temporary weakness or paralysis). However, serious side effects are very rare if vaccines are used appropriately.

Systematic and extensive research has found no link between vaccines and other serious side effects such as autism. Reports that vaccines cause AIDS or sterility are urban legends and have no factual basis. Refusing vaccination to avoid side effects increases the risk of getting an infection, which is a much greater threat to health than are possible side effects of vaccination.

Did You Know...

  • Vaccinations can benefit people other than those receiving the vaccine.

Children and adolescents, older adults, and people whose immune system is impaired are often the most vulnerable to developing vaccine-preventable infections. They are also often the most vulnerable to developing serious symptoms from these infections. For example, whooping cough (pertussis) tends to cause severe symptoms in infants but can be as mild as a cold in older, otherwise healthy people. Although it is most important to vaccinate the most vulnerable people, vaccinating other people is also important. Doing so prevents illness in the vaccinated person and also reduces the number of people in the community who could develop and thus transmit infection to more vulnerable people. Thus, deaths and serious complications in the community are reduced by vaccinating as many people as possible. This effect is called herd immunity.


Screening is testing of people who are at risk of a disorder but do not have any symptoms. Screening can allow for early treatment, sometimes keeping disorders from turning deadly. For example, abnormalities of the cervix or colon can be diagnosed and cured before they become cancerous.

Screening programs have greatly reduced the number of deaths caused by some disorders. For example, deaths due to cervical cancer, once the most common cause of cancer death among American women, have decreased 75% since 1955. Screening can also diagnose disorders that are not curable but that can be treated before they cause too much damage (for example, high blood pressure).

Did You Know...

  • Some tests to diagnose disorders before symptoms occur (screening tests) can potentially cause more harm than good.

People might think that any test capable of diagnosing a serious disorder should be done. However, this is not true. Although screening can offer great benefits, it can also create problems. For example, screening test results are sometimes positive in people who do not have disease, and a certain number of those people then have additional follow-up tests and/or treatments that are unnecessary, often expensive, and possibly painful or dangerous.

Also, sometimes screening reveals abnormalities that cannot or need not be treated. For example, prostate cancer often grows so slowly that in older men, the cancer is unlikely to affect their health before they die from another cause. In such cases, the treatment can be worse than the disease. Whole-body computed tomography scans are not recommended because they do not have benefits (such as saving lives) that exceed the risks (such as developing disorders caused by the radiation exposure, including cancer). In addition, when people are told they could have a serious disorder, they can become anxious, which can affect health.

Because of these issues, screening is recommended only when

  • The person has some real risk of developing the disorder.

  • The screening test is accurate.

  • The disorder can be more effectively treated when diagnosed before symptoms develop.

  • The health care benefits of appropriate screening make it relatively cost-effective.

Some screening tests (such as tests for cervical and colon cancers) are recommended for all people of a certain age or sex. For people at increased risk because of other factors, tests may be recommended at an earlier age or at more frequent intervals, or additional tests may be recommended. For example, a person with a family history of colorectal cancer or with a disease that increases the chances of developing colorectal cancer such as ulcerative colitis, would be advised to have a screening colonoscopy more often than is normally recommended for people at average risk. A woman with a strong family history of breast cancer would likely be advised to be screened for breast cancer with magnetic resonance imaging (MRI) in addition to mammography.

Some screening measures are recommended for people with certain disorders. For example, people with diabetes should check their feet at least once daily for redness and ulcers, which, if ignored, may result in severe infection and ultimately amputation.

Some Recommended Screening Tests for Adults*,†




How Often

Abdominal aortic aneurysm

Abdominal ultrasonography

Men aged 65–75 who smoke or who have previously smoked


Alcohol misuse



Once and periodically, as when circumstances change (for example, when under new stresses or if lifestyle changes)

Amblyopia and strabismus

Vision testing and eye examination

Children aged 5 or younger

Once before age 6 months and again at age 6 months–3 years and at age 3–5 years

Breast and ovarian cancers

Genetic counseling and possible genetic testing for the BRCA mutation, which indicates increased risk of breast and ovarian cancers

Women with several close, usually first-degree relatives who have had breast cancer (see Breast Cancer : Risk Factors for Breast Cancer) or ovarian cancer (see Ovarian Cancer)


Breast cancer


Women aged 50–74

For women under age 50, consultation with their doctor about individualized screening if they have concerns

Every 2 years


Women at high risk (such as those with close family members who have had breast cancer)

When mammography is done

Cervical cancer

Papanicolaou (Pap) test or another similar test and sometimes a test for human papillomavirus (HPV)

All women who have ever been sexually active and have not had their cervix removed

Every 2–5 years in women aged 21–65

Chlamydial infection

A DNA test using a urine sample or a sample taken from the vagina with a swab

Sexually active women who are 25 or younger and women who are over 25 and have risk factors (such as several sex partners or a sexually transmitted disease)


Colorectal cancer

Colonoscopy, sigmoidoscopy, or tests to check stool for blood

Adults aged 50–75

Every 10 years for colonoscopy, every 5 years for sigmoidoscopy, or yearly for stool tests

Dental problems

Check-up with dentist


Every 3–12 months for children and adolescents under age 18

Every 3–24 months for people aged 18 or older


Questions, including standardized questionnaires


Once and periodically, such as during stressful circumstances (for example, divorce, job or lifestyle change, or death in the family)


Blood tests to measure hemoglobin A1C or the blood sugar level

Adults who are older than 45 or overweight, who have high blood pressure or high levels of cholesterol and/or other fats (lipids) in the blood, or who have had high blood sugar levels in the past

Every 3 years, depending on risk factors and the results of previous tests


A DNA test using a urine sample or a sample taken from the vagina with a swab

Pregnant women and young women who are sexually active

Once and periodically, as when circumstances change (such as with new sex partners or after becoming pregnant)

Hearing loss

Hearing examination

Adults aged 65 or older


Hemolytic disease of the newborn

Rh0(D) incompatibility screening

Sometimes other tests, depending on test results (see Rh Incompatibility : Diagnosis)

Pregnant women

At the first prenatal visit

Hepatitis B

Blood test for infection with the hepatitis B virus

Pregnant women

At the first prenatal visit

Hepatitis C

Blood test for infection with the hepatitis C virus

People born between 1945 and 1965 and people who have risk factors (such as those who use intravenous drugs)


High blood pressure (hypertension)

Blood pressure measurement


Every office visit or annually

High levels of cholesterol and/or other fats (lipids) in the blood

Blood tests to measure lipid levels, often done after fasting

Men aged 35 or older

Women aged 45 or older if they have risk factors for coronary artery disease

Every 5 years or more often if levels are abnormal or if people have certain disorders (coronary artery disease, diabetes, peripheral arterial disease, or stroke)

Human immunodeficiency virus (HIV) infection, including AIDS

Blood or saliva test for infection with the virus

Everyone aged 15–65 years, those over 65 with risk factors for HIV infection, and all pregnant women

At least once and if new high-risk activity occurs (for example, having more than one sex partner, using injection drugs, and, in men, having sex with men)


Dual x-ray absorptiometry (DXA) to measure bone density

All women aged 65 or older and women under 65 if they are at risk of fractures due to osteoporosis (see Osteoporosis : Diagnosis of Osteoporosis)

At least once

Overweight in adults and children

Growth disturbance in children

Measurement of height and weight

Calculation of body mass index (BMI)


Every scheduled office visit or annually

Refractive errors (poor vision)

Vision testing (screening examinations do not require an optometrist or ophthalmologist)


Children: Once at age 0 to 6 months and again at age 6 months to 3 years, at age 3–5 years, and at ages 5, 6, 8, 10, 12, and 15 years

Adults: Every 1–2 years for people aged 18–64

Every year for those aged 65 and older


Blood test for the infection

Adults with risk factors (such as having several sex partners, having had a previous sexually transmitted disease, men's having sex with men) and all pregnant women

Once and periodically, such as when circumstances change (such as with new sex partners or after becoming pregnant)

Tobacco use


All adolescents and adults

Every office visit

*Based on recommendations by most major authorities in the United States. However, differences do exist among their recommendations.

Screening measures that can be done at home include regularly measuring weight and, once yearly, checking the skin for changes and for sores that bleed. People can ask another person (such as a spouse) to check their skin in areas that are difficult to see, such as the back or behind the ears.

MRI = magnetic resonance imaging.

Preventive Drug Therapy

Preventive drug therapy (also known as chemoprevention) is the use of drugs to prevent disease. For such therapy to be recommended, the person must be at risk of the disorder being prevented and be at low risk of side effects caused by the drug being considered. Preventive drug therapy is clearly helpful in, for example, prevention of infection in people with certain disorders (such as AIDS), prevention of headache in people with migraines, and many other specific situations. Although preventive drug therapy is effective only in specific situations, some of those situations are common, so the therapy is useful for many people. For example, for adults at risk of coronary artery disease or stroke, aspirin is usually recommended. Newborns routinely receive eye drops to prevent gonococcal infection of the eyes. Women who are at high risk of breast cancer may benefit from preventive drug therapy (for example, with the drug tamoxifen).

Some Strategies for Preventing Major Health Problems*

Health Problem

Preventive Measures


Do not smoke (to prevent lung cancer and many other cancers).

Eat a balanced diet high in fiber, fruits, and vegetables and limited in fat (particularly saturated fat and trans fatty acids) and calories (to prevent breast cancer and colorectal cancer).

Reduce consumption of salt- or smoke-cured food (to prevent stomach cancer).

Avoid too much sun exposure, and use sunscreens with a high sun-protection factor (to prevent skin cancer).

Make sure children get the HPV (human papillomavirus) vaccine (to prevent cervical cancer and throat cancer).

Consider taking drugs recommended to prevent cancer (such as tamoxifen for women at high risk of breast cancer).

Get recommended screening tests.

Chronic obstructive pulmonary disease

Do not smoke.

Avoid exposure to toxic substances (especially in industrial settings).


Exercise regularly.

Eat a balanced diet.

Maintain recommended body weight.

Maintain normal lipid levels through diet and, if necessary, drugs.

Maintain normal blood pressure through diet, exercise, stress reduction, and, if necessary, drugs.

Do not smoke (type 2 diabetes).

Heart disease and stroke

Maintain normal cholesterol and other fat (lipid) levels through diet and drugs (if necessary).

Maintain normal blood pressure through diet, exercise, stress reduction, and drugs (if necessary).

Consume a balanced diet high in fiber, fruits, and vegetables and limited in fat (particularly saturated fat and trans fatty acids) and calories.

Maintain recommended body weight.

Do not smoke.

Exercise regularly and include aerobic exercise (such as brisk walking, bicycling, and jogging) and muscle-strengthening exercise (such as training with free weights or weight machines).

Take aspirin if recommended (for most adults at high risk of coronary artery disease).

Do not use cocaine.

High blood pressure

Consume a balanced diet high in fiber, fruits, and vegetables and limited in salt, fat (particularly saturated fat and trans fatty acids), and calories.

Exercise regularly and include aerobic exercise and muscle-strengthening exercise.

Maintain normal cholesterol through diet, exercise, and drugs (if necessary).

Maintain recommended body weight (through diet and exercise).

Do not smoke.


Get the influenza vaccine every year (particularly infants, older adults, and people who have a heart, lung, or immune system disorder).

Liver disease

Drink alcohol in moderation if at all.

Get the vaccine for hepatitis A and B (for all children and for adults with risk factors for the disease).


Do muscle-strengthening and stretching exercises.

Remain physically active.

Maintain recommended body weight.


Consume adequate amounts of calcium and vitamin D (in the diet or in supplements).

Do weight-bearing exercises (for example, walking, jogging, tennis, and dancing) every day for at least 30 minutes.

Take bone-strengthening drugs if prescribed by a doctor.

Limit consumption of caffeine and alcohol (to one drink a day).

Do not smoke.


Get the pneumonia (pneumococcal) vaccine once, repeated once after 5 years for people at high risk, including those over age 65.

Sexually transmitted diseases

Practice abstinence or limit the number of sex partners.

Use condoms and follow safe sex practices.

Tooth loss

Brush teeth and use dental floss regularly.

Limit how often sweets are consumed.

Visit a dentist regularly.

Take supplemental fluoride if needed (for example, if the water source for preschool children older than 6 months is fluoride-deficient).

*In addition to these preventive measures, people should have recommended screening tests (see Table: Some Recommended Screening Tests for Adults*,†).

1 drink = one 12-ounce can of beer, one 5-ounce glass of wine, or 1.5 ounces of liquor (such as whiskey).

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