DALLAS, Nov. 4 -- Even small weight gains can increase a person's risk of having a heart attack, according to a report that stresses the importance of a low-fat diet and regular physical activity to prevent obesity.
In an American Heart Association science advisory titled "Obesity and Heart Disease," published in the association's journal Circulation, the report's author, Robert H. Eckel, M.D. says, "Obesity is emerging as an independent risk factor for diseases of the heart. We've known for a long time that obesity was related to heart disease, because it contributes to the development of high blood pressure, high cholesterol and diabetes mellitus."
However, recent studies have shown that minimal increases in a person's body mass index (BMI) are associated with an increased risk of both nonfatal and fatal heart attacks, even if the person does not have other risk factors for heart disease. Body mass index is defined as weight in kilograms divided by height in meters squared.
"In addition, an individual may be at greater risk for developing high blood pressure, diabetes mellitus and high cholesterol -- serious risk factors for heart disease -- if his or her weight is carried in the mid-section, instead of the hip or thigh area," says Eckel, professor of medicine and physiology at the University of Colorado Health Sciences Center.
"Weight reduction appears to be helpful in reducing the risk of heart attacks and congestive heart failure for many people" says Eckel. "For most people who are overweight -- with a BMI between 25 and 30 -- eating a lower-calorie, low-fat diet and becoming more physically active are very helpful at improving overall health. A healthy weight loss of about one pound per week is considered reasonable for most people, unless there are more serious medical conditions such as congestive heart failure."
"For people with a BMI over 30, treatment with weight loss drugs may be appropriate. However, since the withdrawal of fenfluramine and dexfenfluramine from the market, few pharmaceutical choices remain," noted Eckel. The drugs were withdrawn because of concern over a potential link between the drugs and valvular heart disease and primary pulmonary hypertension. "When a patient's BMI is over 35 and he or she has other diseases, such as high blood pressure, diabetes mellitus, elevated cholesterol levels, severe weight-bearing joint disease, or obstructive sleep apnea, surgery should be considered," he says.
Obesity is increasingly prevalent. According to the National Health and Nutrition Examination Survey (1988-94), 54 percent of the population has a BMI equal to or greater than 25. "We consider anything above 25 is an indication that a person may see adverse health effects from this amount of body fat," says Eckel.
Because it is difficult to lose weight and keep it off, it is imperative to prevent weight gain in the first place. Of the most effective means for doing that is calorie restriction, a low- fat diet and physical activity, says Eckel. Obesity contributes to congestive heart failure, which affects nearly 5 million people today. It is associated with changes in the heart's left ventricle that may increase the risk of sudden death, regardless of whether the person has high blood pressure.
Co-authors are members of the Nutrition Committee of the American Heart Association.