P E R S P E C T I V E S O N T H E N E W S
Diabetes and Obesity
ZACHARY T. BLOOMGARDEN, MD tion that reduced adipocyte size may be related to insulin resistance), increased blood pressure, and increased triglyceride levels. Such individuals often are offspring of type 2 diabetic parents, themselves developing type 2 diabetes at relatively youngages, having history of myocardial infarction and of cholesterol cholelithiasis. Criteria for the MONW state are similar to those for metabolic syndrome (4), including hyperinsulinemic individuals with normal weight and multiple cardiovascular disease (CVD) risk factors (5). An alternative approach is to identify nonobese hypertensive individuals, recognizing this to be a group characterized byincreased insulin and triglyceride levels and by decreased insulin sensitivity (6). In the U.S. National Health and Nutrition Surveys, MONW constitute a large number of at-risk individuals in the U.S. population (7). A Canadian study evaluating normal-weight individuals with features of insulin resistance showed a tripling in risk of CVD (8). Schneider asked how knowledge of the existence of this groupshould inﬂuence our thinking, speciﬁcally addressing the usefulness of relying on simple measures of body weight, as the MONW concept implies that a large number of normal-weight individuals would beneﬁt from interventions now thought appropriate for obese individuals. He discussed the usefulness of measures of adipose tissue other than that of total fat mass and the question of whether measuresof insulin resistance and hyperinsulinemia would be useful in ascertainment of these abnormalities. Clinically, we are not readily able to assess adiposity. The 75-kg man at age 53 years typically has 7 kg more fat and less lean mass than he had at the same weight at age 25 years, without apparent difference in physiognomy. Nondiabetic, nonobese offspring of type 2 diabetic parents will be found tohave increased fat mass despite normal BMI (9). The concept of abnormal fat distribution dates to Vague’s differentiation between benign and metabolic obesity, with relatively few metabolic abnormalities in the former group, the latter exhibiting the pattern of increased abdominal fat. There is clearly
Perspectives on the News commentaries are now part of a new, free monthly CMEactivity. 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 continuingmedical education for physicians. his 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. Obesity Gerald Reaven (Stanford, CA) argued that obesity is not synonymous with insulin resistance. Measuring the steady-state plasmaglucose (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 thevariability 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 abdom-...