Diabetes and Obesity

Abstract

Perspectives on the News commentaries are now part of a new, free monthly CME activity. The Mount Sinai School of Medicine, New York, New York, is designating this activity for 2.0 AMA PRA Category 1 credits. If you wish to participate, review this article and visit www.diabetes.procampus.net to complete a posttest and receive a certificate. The Mount Sinai School of Medicine is accredited by the Accreditation Council for Continuing Medical Education (ACCME) to provide continuing medical education for physicians. This is the fourth in a series of articles based on presentations at the American Diabetes Association's 67th Scientific Sessions, 22–26 June 2007 in Chicago, discussing aspects of the interrelationships between diabetes and obesity. Gerald Reaven (Stanford, CA) argued that obesity is not synonymous with insulin resistance. Measuring the steady-state plasma glucose (SSPG) during infusion of glucose and insulin to characterize insulin sensitivity, there is a continuous distribution of levels with a six- to eightfold variation from least to most insulin sensitive in the apparently normal population. SSPG correlates with both waist circumference and BMI in men and women but, Reaven noted, with “enormous variability” (1), only explaining ∼25% of the variability in this measure. BMI and waist are similar in their power to identify individuals with abnormal SSPG, as well as in predicting abnormalities of glucose, triglyceride, HDL cholesterol, and other parameters associated with insulin resistance. A study of individuals of Malay, Chinese, and Indian ethnicity showed that metabolic syndrome frequently occurs without satisfying criteria for abdominal obesity (2), with metabolic syndrome similarly only being moderately associated with directly measured visceral fat. Furthermore, not all obese individuals have insulin resistance, and those obese individuals showing metabolic benefits of weight loss belong to the insulin-resistant subset in the lowest tertile of insulin sensitivity. Comparing adipocyte cell size distributions of insulin-resistant versus …