Introduction

The traditional practice of medicine focuses on evaluating symptoms, determining what disease is causing those symptoms, and treating the disease. In contrast, preventive medicine aims to prevent diseases from occurring in the first place or to diagnose disease at an early stage, often when there are no symptoms and when recovery is most achievable. Prevention is the area of medicine and health care that focuses on promoting health and reducing risk through specific measures taken to avoid illness, disability, and premature death.

Preventive medicine depends heavily on a person's risk profile, that is, the person's risk of developing a disease based on such factors as age, sex, family history, lifestyle, and physical and social environment. Once a person is made aware of his risks based on the risk profile, he can take steps to minimize them.

Everyone is subject to the good or bad fortunes of chance, and ill health sometimes is the result of injuries or other exposures that cannot be predicted. However, genetic makeup and family history are factors that can predict some risks and, although they cannot be controlled, can provide valuable clues as to a person's risk for certain diseases. For example, a person with a family history of diabetes is at higher risk than most people of developing diabetes and thus would be wise to undergo blood sugar monitoring periodically and receive additional counseling in ways to help avoid the onset of diabetes. 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 undergo a screening sigmoidoscopy or colonoscopy (see Section 9, Chapter 131) more often than is normally recommended for people at average risk. A woman with a family history of breast cancer would likely be advised to undergo screening mammography at an earlier age.

A person's lifestyle choices are also considered when determining the risk profile. For example, how well a person handles stress is important; reducing stress helps reduce blood pressure, which reduces the risk of stroke and heart attack. Smoking cigarettes and not exercising regularly can greatly increase a person's risk of many deadly diseases, and these factors are clearly controllable. A person who smokes or is sedentary, especially if there is a family history of heart disease, may be offered additional counseling about the risks of smoking or the benefits of exercise. A person who eats large amounts of fatty foods may be at increased risk of atherosclerosis (see Section 3, Chapter 32) and thus might benefit from dietary counseling and more frequent checks of blood cholesterol level (see Section 12, Chapter 157).

Social and physical environment (for example, violence in the community, lead paint in the home, a dangerous work environment) can also affect a person's health; these factors are also considered when determining a person's risk profile. For example, a person who works with asbestos is at increased risk of developing lung disease, so a health care professional may suggest periodic chest x-rays and may strongly counsel against smoking. Recommendations may also include using safety devices at work, such as a filtered respirator-style mask. Another example would be people whose jobs involve repeated movements with the wrists extended, such as performing assembly line work or using a computer keyboard; such work may increase the risk of carpal tunnel syndrome or other injuries (to nerves, tendons, and ligaments) associated with repetitive use of certain parts of the body. A health care professional may recommend reducing the amount of uninterrupted time spent doing the activity that triggers the problem and modifying workplace furniture and equipment in order to reduce physical stress on the affected parts of the body.

See the table Health Risk Assessment.