Risk factors for heart disease.

Factors that increase the risk of heart attack can be grouped into two classifications: major and contributing. The major risk factors that can not be changed are heredity (inherited traits), males sex, and increasing age. Those that result from modifiable lifesytle habits are tobacco smoke, high cholesterol, high blood pressure, and physical inactivity.

Contributing risk factors are those associated with increased risk of cardiovascular disease. For heart attack, these include diabetes and obesity. Stress may be a contributing factor. The more risk factors a person has, the greater the chance of developing heart disease.

Major risk factors that can't be changed

Heredity. A tendency toward heart disease or atherosclerosis seems to be heredity. Race is a consideration, too. African-Americans have moderate high blood pressure twice as often as whites and severe hypertension three times as often. Consequently, their risk of heart disease is greater.

Being male. Men have a higher risk of heart attack than women earlier in life. After menopause, women's death rate from heart disease increases.

Increasing age. About four out of five people who die of heart attack are age 65 or older. At older ages, women who have heart attacks are twice as likely as men to die from them within a few weeks.

Tobacco smoke. Cigarette smoking is the biggest risk factor for sudden cardiac death. Smokers have two to four times the risk of nonsmokers. Smokers who have a heart attack are more likely to die and die suddenly (within an hour) than nonsmokers.

Evidence also indicates that chronic exposure to environmental tobacco smoke (second-hand smoke, passive smoking) increases the risk of heart disease. The possibility of death due to heart disease is increased by about 30% among those exposed to environmental tobacco smoke at home and could be much higher in those exposed in the workplace, where higher levels of environmental tobacco smoke may be present.

High blood cholesterol. The risk of coronary heart disease rises as blood cholesterol levels rise. When other risk factors (such as high blood pressure and tobacco smoke) are present, this increases even more. A person's cholesterol level is affected by age, sex, heredity, and diet.

Based on large population studies, blood cholesterol levels below 200 mg/dl (milligrams per deciliter) in middle-aged adults seem to indicate a relatively low risk of coronary heart disease. A level of 240 mg/dl or higher approximately...