Being Overweight is a Factor Independent of Obesity-related Conditions
WEDNESDAY, July 31 -- Obesity alone makes the heart pump poorer, according to a new study that says extremely overweight people are twice as likely to get heart failure as people of normal weight.
The research also finds that your risk for heart failure increases each time you find yourself loosening your belt.
A report from the long-running Framingham Heart study is the first to say that obesity, in and of itself, is a cause of heart failure, which is a life-threatening weakened ability to pump blood to the body.
"It has been known that extreme obesity is associated with an increased risk of heart failure," says Dr. Ramachandran S. Vasan, associate professor of medicine at Boston University School of Medicine and the lead author of the report appearing in tomorrow's New England Journal of Medicine.
"The question is whether the risk is independent of the other risk factors associated with obesity, such as high blood pressure and diabetes," he adds. "We show in our investigation that the relationship between body mass index and heart failure is a continuum. As body mass index increases from normal to overweight to obesity, the risk of heart failure increases."
Body mass index (BMI), which is weight in kilograms divided by the square of height in meters, is the accepted standard for assessing weight. A BMI under 25 is regarded as normal. A reading of 25 to 29.9 indicates overweight and obesity is a BMI of 30 or over.
The new report looked at 5,581 participants in the Framingham study over 14 years, during which 498 of them developed heart failure. "After adjustment for established risk factors, there was an increase in the risk of heart failure of 5 percent for men and 7 percent for women for each increment of 1 in BMI," says the journal report.
The relationship held up when the researchers adjusted for the effect of age, sex, smoking status, alcohol consumption, diabetes and heart valve disease. Obese women had double the risk of heart failure of normal-weight women; for men, the risk was increased by 90 percent.
"From a public health perspective, this is an additional motivation for telling people to lose weight," Vasan says. "Heart failure is now added to the list of medical problems associated with obesity."
While it's possible for some highly muscular people to have a BMI in the overweight range, it is fat, not muscle, that causes a high reading in most cases, Vasan says.
The report comes amid growing concern over what medical authorities describe as an epidemic of obesity in the United States. Nearly 60 percent of adult Americans are obese or overweight, and weight problems have increased among young people. The National Heart, Lung and Blood Institute, which sponsors the Framingham study, estimates that 13 percent of children ages 6 to 11 are overweight, as are 14 percent of adolescents ages 12 to 19.
For Dr. Arthur Frank, medical director of the weight management program at George Washington University, the finding is a call for more research and early intervention to prevent the damage done by obesity.
"We're very good at treating all the consequences of obesity -- high blood pressure, high cholesterol, diabetes -- which is what we end up doing. But we're not very good at treating obesity," says Frank, who is treasurer of the Washington-based American Obesity Association. "That doesn't make sense. Obesity is the mother of them all. If we can get your weight down, your diabetes looks better, your cholesterol looks better, your blood pressure looks better."
And yet, he says, "we haven't directed sufficient resources to solve the problem. There is not enough research commitment or dedication to solving the problem. What we do is skirt around it."Young people should be a major target of an obesity reduction program, Arthur adds. "The sooner you deal with it early in life, the better. Everyone who is now obese was at one time a little overweight. Obesity is a killer disease and we have to start thinking about early intervention," he says.