NEW YORK (Reuters Health) - Middle-aged spread may put people at risk of developing artery-clogging plaques, even if their weight is within the normal range Dallas-based researchers reported Monday.
In a study of more than 2,700 middle-aged adults, researchers at the University of Texas Southwestern Medical Center found that the larger study participants' waists were in relation to their hips, the larger their risk of having calcium buildup in the arteries, as called atherosclerosis.
Calcium is a component of the plaques that mark atherosclerosis, a hardening and narrowing of the arteries that can trigger cardiovascular events, such as heart attack and stroke. Doctors can measure coronary artery calcium using non-invasive imaging; the resulting calcium "score" indicates whether atherosclerosis is present and how severe it is.
In the current study, waist-to-hip ratio was more closely associated with calcium scores and the risk of atherosclerosis than was body mass index (BMI). Calculated as the ratio of weight to height, BMI is often used to determine is a person is over- or under-weight.
The findings, to be published in the Journal of the American College of Cardiology, bolster previously reported evidence that excess fat in the abdomen, specifically, puts the heart at risk.
In fact, a "pot belly" seems to raise this risk even when a person's overall weight is normal, according to study co-author Dr. James A. de Lemos. "This is a 'straight line,' or linear, association, meaning that the risk is not confined just to those with large bellies," he told Reuters Health.
When it comes to your waistline, de Lemos said, the less fat the better.
Other studies have similarly linked waist size to heart disease and major risk factors for it, like high blood pressure and type 2 diabetes. The current findings, de Lemos explained, show that abdominal fat may be key in the early stages of heart disease, when people have plaque in their arteries but no chest pain or other symptoms.
"It implies that one important way by which larger waist-to-hip ratio confers risk is through plaque buildup," he said.
One reason waist-to-hip ratio is more precise than BMI in predicting heart risks is that the latter may not accurately reflect a person's amount of body fat. A muscular man, for example, may have a high BMI but not a high percentage of body fat.
But in this study, waist-to-hip ratio was also more closely associated with atherosclerosis than a simple measure of waist circumference was. One possibility, de Lemos noted, is that excess fat in the hips and thighs may actually be protective against heart disease -- as long as the waistline remains trim.
In other work, his team has found that people with large hips have lower odds of some heart disease risk factors.
But the bottom line, once again, is that people need to maintain a healthy diet and regular exercise throughout life -- starting early on, according to de Lemos.
The "waist battle," he said, has to be fought every day.
SOURCE: Journal of the American College of Cardiology, August 21, 2007.
