The presence of visceral fat in older men and women is associated with increased risk for metabolic syndrome, even in normal-weight individuals, according to an article in the April 11th issue of the Archives of Internal Medicine.

Metabolic syndrome, a disorder that includes dyslipidemia, insulin resistance, and hypertension, affects 22 percent of adults in the U.S. and an even higher (42) percent of older men and women, according to background information in the article. In addition to overweight and obesity, patterns of fat distribution in middle-aged adults may confer additional risk for metabolic syndrome, but it was not known whether this is true for older individuals.

Bret H. Goodpaster, PhD, and his American colleagues examined the association between the pattern of distribution of body fat and metabolic syndrome in 3,035 men and women aged 70 to 79 years. The distribution of body fat was determined using computed tomography (CT) scanning. Patients were examined and characterized as having metabolic syndrome if they met at least three of the following criteria: waist circumference greater than about 40.2 inches in men or 34.7 inches in women; elevated blood triglyceride levels; low high density lipoprotein (HDL) cholesterol levels; hypertension, treated or untreated; and elevated blood sugar level, treated or untreated.

Individuals were classified as normal weight, overweight or obese based on body mass index, with an index of less than 25.0 considered normal weight, overweight defined as an index of 25.0-29.9 and obese defined by an index of greater than 29.9.

Visceral fat (fat found in the deeper tissues and around the body's organs rather than just under the skin) was associated with metabolic syndrome in older men and women whether they were normal weight, overweight or obese. Subcutaneous abdominal fat was associated with metabolic syndrome only in normal weight men. Intermuscular fat was associated with the syndrome in normal and overweight men. A surprising finding, according to the authors, was that subcutaneous thigh fat was inversely associated with metabolic syndrome in obese men and women.

"In conclusion, excess accumulation of either visceral abdominal or muscle adipose tissue is associated with a higher prevalence of metabolic syndrome in older adults, particularly in those who are of normal body weight," the authors wrote. "This suggests that practitioners should not discount the risk of metabolic syndrome in their older patients entirely on the basis of body weight or BMI. Indeed, generalized body composition, in terms of both body mass index and proportion of body fat, does not clearly distinguish older subjects with the metabolic syndrome."