AMA: Intra-Abdominal Fat is Major Determinant of Important Cardio-Vascular Risk Factor in Older Women
WASHINGTON, DC -- October 14, 2004

The location of fat within the body is a better risk indicator for heart disease in older women than the level of obesity, according to a new study in the Nov. 2004 issue of The Journal of Clinical Endocrinology & Metabolism, presented today at the American Medical Association's 23rd Annual Science Reporters Conference in Washington D.C. The researchers identified a single factor that identifies women with metabolic syndrome, a multi-component risk factor for cardiovascular disease, according to Barbara Nicklas, Ph.D., principal investigator in the study.

"Everyone who is obese does not seem to be at the same risk for cardio-vascular disease. We were interested in why some obese people are at a higher disease risk than others," said Dr. Nicklas, associate professor in the section on gerontology and geriatric medicine in the department of internal medicine and the Center for Human Genomics at Wake Forest University School of Medicine in Winston-Salem, N.C. "In our study we used metabolic syndrome, a collection of five indicators, as a marker to differentiate women who were at a higher risk for subsequent cardiovascular disease."

In this study, Dr. Nicklas and her colleagues examined 58 obese, postmenopausal women, one-half of whom had metabolic syndrome, to determine whether four factors: aerobic fitness, body composition, body fat distribution and inflammation, differed between women with and without metabolic syndrome.

"We found that where the body fat is stored was the main determinant of who had metabolic syndrome," Dr. Nicklas said. "We were not just looking at whether the fat was carried on the hips or in the abdomen. We determined whether abdominal fat was stored between the skin and the abdominal muscle wall, what we call subcutaneous fat, or stored as visceral fat, which is beneath the muscles and wrapped around the internal organs. There have been a number of studies that indicate that visceral fat is worse because it surrounds vital organs and may lead to more fat metabolism by the liver."

"There was a dramatic difference in percentage of visceral fat between those women with metabolic syndrome and the other women in the study," Dr. Nicklas said. "Women with metabolic syndrome had 33 percent more visceral fat, but were similar in all other respects, including the waist circumference, with almost exactly the same amount of subcutaneous fat and identical fat cell size."

"Our study makes it clear that all fat is not alike and points to the importance of improving our understanding of visceral fat," Dr. Nicklas said. "We need to learn what causes the fat to be stored beneath the muscles or around the internal organs and determine treatment options to reduce this visceral fat. More studies are also needed to determine whether measurement of visceral fat could be used by doctors for more accurate prediction of cardiovascular disease risk in obese individuals."

"While we need much more research to understand these risk factors, there are things people can do to reduce their risk," Dr. Nicklas said. "High intensity exercise seems to preferentially reduce visceral fat and general weight reduction helps, too."

SOURCE: American Medical Association