Body composition, visceral fat, leptin, and insulin resistance in Asian Indian men

There is a high prevalence of type 2 diabetes mellitus and coronary artery disease among urban and migrant Asian Indians despite the absence of tradit ional risk factors. Evidence exists that Asian Indians are more hyperinsuli nemic than Caucasians and that hyperinsulinemia may be important in the dev elopment of these diseases. To test whether insulin action was related to t otal or regional adiposity and to explore the potential role of plasma lept in and lipids, we measured insulin-mediated glucose disposal by the euglyce mic insulin clamp, adipose distribution and muscle Volume using computed ax ial tomography, and fasting serum leptin and lipid levels in 20 healthy Asi an Indian male Volunteers (age, 36 +/- 10 yr). A mean body mass index of 24.5 +/- 2.5 kg/m(2) was associated with an unusu ally high percentage of body fat (35 +/- 7%). The majority of the fat was s c, and 16% was visceral (intraabdominal) adipose tissue. The majority (66%) of these nonobese men were insulin resistant. The mean fasting serum lepti n level was 7.6 +/- 3.3 ng/mL. Insulin action was inversely correlated with visceral adipose tissue, not t otal or abdominal sc adipose tissue. In contrast, leptin levels correlated with sc and total (not visceral) adipose tissue. Serum triglyceride and hig h density lipoprotein cholesterol levels were inversely correlated with eac h other and were directly related to insulin resistance and visceral (not s ubcutaneous) fat. Increased Visceral fat in Asian Indians is associated with increased genera lized obesity, which is not apparent from their nonobese body mass index. I ncreased visceral fat is related to dyslipidemia and increased frequency of insulin resistance and may account for the increased prevalence of diabete s mellitus and cardiovascular disease in Asian Indians.