What's important about elderly women's fat? Amount or location?

For elderly women, the location of excess fat may be more important for their cardiovascular health than overall obesity, according to a surprising new study published in today’s rapid access issue of Circulation: Journal of the American Heart Association. In a study of 1,356 women ages 60-85, Danish researchers found that those with excessive peripheral fat ? located in the arms, legs, hips and buttocks ? had less atherosclerosis than those whose fat was stored mostly in their abdominal area (visceral fat) and other central parts of the body.

From the American heart Association:
What’s important about elderly women’s fat? Amount or location?

DALLAS, March 18 ? For elderly women, the location of excess fat may be more important for their cardiovascular health than overall obesity, according to a surprising new study published in today’s rapid access issue of Circulation: Journal of the American Heart Association.

In a study of 1,356 women ages 60-85, Danish researchers found that those with excessive peripheral fat ? located in the arms, legs, hips and buttocks ? had less atherosclerosis than those whose fat was stored mostly in their abdominal area (visceral fat) and other central parts of the body.

“Our most important and somewhat surprising finding is that peripheral fat mass may overrule the adverse effects of visceral fat mass,” says the study’s lead author L?szl? B. Tank?, M.D., Ph.D., a research physician specializing in women’s health at the Center for Clinical and Basic Research in Denmark.

Still, he says, women with excess peripheral fat who have high blood pressure, diabetes or high cholesterol should have their cardiovascular health monitored closely.

“Obesity is recognized as a major risk factor for coronary heart disease,” says American Heart Association President Robert Bonow, M.D. “Central obesity has previously been shown to particularly increase cardiovascular risk.

“Although this is a very interesting study suggesting that all fat is not the same in women, until we know more, it’s still important to avoid weight gain,” Bonow says. “Since we can’t design our bodies and direct fat to specific locations, it’s important to exercise and watch our weight.”

Men gain weight in the belly (central fat mass), whereas women tend to accumulate peripheral fat or fat in general, Tank? says. In men, central fat is strongly associated with the development of atherosclerosis, the buildup of artery-clogging plaque that can lead to a heart attack or stroke. In women, the association between atherosclerosis and body fat is less clear, he explains.

Central fat mass is the “pinchable” fat of the abdomen just below the skin and, more importantly, the deeper, more dangerous visceral fat found on and near the gastrointestinal system, Tank?says. Visceral fat is more strongly implicated in the development of atherosclerosis and impairments in blood sugar metabolism that can progress to type 2 diabetes, Tank? says. Peripheral fat is found just about anywhere else on the body.

Researchers measured body fat in the central and peripheral regions and expressed it as a percentage of the body’s total soft tissue mass. They used X-ray to view atherosclerosis in the abdominal part of the aorta. Researchers assigned an aortic calcification score (AC score) ? a measure of the buildup of calcium in the arteries that marks the severity of atherosclerosis ? on a scale from 0 to 24 for the presence and extent of calcified deposits in the arterial wall.

The researchers divided the subjects into groups based on their quartiles for percentages of central and peripheral fat mass. They then looked at the four extremes: 1) lean women with low percentages of both kinds of fat; 2) women with low central fat and high peripheral fat; 3) women who had high central and low peripheral fat, and 4) obese women with generalized fat (high percentages of both central and peripheral fat).

Researchers found that women with high central fat and low peripheral fat had the most severe problems with blood sugar and cholesterol metabolism and the most atherosclerosis (an average AC score of 5.1). In contrast, low amounts of central fat and high peripheral fat seemed to have the most favorable effects on blood sugar metabolism. The least severe atherosclerosis was found in generally obese women.

Once considered just a storage area for extra calories, fat is being reevaluated as an important metabolic resource for the body, Tank? says.

“Central fat and peripheral fat secrete different hormone-like substances that have contrasting effects on insulin sensitivity, which in turn affects lipid and glucose (blood sugar) metabolism accordingly,” he says. “Hormones derived from peripheral fat mass may enhance insulin sensitivity and thereby improve lipid and glucose status, whereas those from visceral fat seem to exhibit the opposite effect.

“Today we know little about the genetic and environmental factors that define or can change body fat distribution in a favorable way,” Tank? says.

This study indicates a need to define cutoff points of simple measurements such as hip or limb circumference that could be used to estimate a person’s peripheral fat mass and its relation to disease risk, he says. In addition, research on the hormone-like substances secreted by peripheral fat cells might lead to new treatments for type 2 diabetes and cardiovascular disease, he says.

Co-authors are Yu Z. Bagger, M.D.; Peter Alexandersen, M.D.; Philip J. Larsen, M.D., Ph.D.; and Claus Christiansen, M.D.

NR03-1038 (Circ/Tanko)

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