Heart risk begins in excess body weight range
- Tuesday, June 9th, 2009
NEW YORK (Reuters Health) - Though studies have come to conflicting conclusions on the health risks of being moderately overweight, maintaining a normal weight should still be a prime goal in preventing heart disease, the American Heart Association (AHA) said on Monday.
In a science advisory published in its journal Circulation, the AHA stresses that even in people who are not obese, excess body fat can raise the risk of health problems like high blood pressure and type 2 diabetes -- major risk factors for heart disease.
The AMA statement is a response to the public confusion generated by some widely reported studies finding that both obese and thin adults tend to die earlier than those with weights in between. One interpretation is that being merely overweight -- and not obese -- is not a health risk.
However, the AHA says, one problem with those studies is that they looked at the relationship between weight and deaths from all causes, which can miss the specific effects that excess fat has on risk factors for cardiovascular disease.
Another problem is that the studies focused on body mass index (BMI), the ratio of weight to height. BMI is an imperfect measure, the AHA says, because it may not accurately reflect a person's fat mass; a muscular man, for instance, can easily have a BMI in the overweight range.
How much fat a person carries, and where he carries it, is key in determining heart risks, the AHA notes. Excess belly fat is considered a particular risk factor for type 2 diabetes and cardiovascular disease.
So focusing on BMI alone and its relationship to all-cause mortality misses the "larger picture," the researchers say.
"This larger picture includes important relationships between BMI and other health outcomes, such as cardiovascular disease and its risk factors," said Dr. Cora E. Lewis, lead author of the advisory and a professor of medicine and public health at the University of Alabama at Birmingham.
"Arguably," she said in an AHA news release, "the most important relationship among the cardiovascular disease risk factors is diabetes, which is significantly more common in overweight than in normal-weight people."
The bottom line, Lewis and her colleagues write, is that "both healthy eating patterns and physical activity have roles in managing weight and cardiovascular disease risk and should be encouraged for all."
Preventing excess weight gain in the first place is crucial, the investigators conclude, extra pounds are notoriously difficult to lose and keep off for the long haul.