Standard definitions of overweight and central adiposity for determining diabetes risk in Japanese Americans

Background: Despite having lower average body mass indexes (BMIs) than do w hites, Asians are at high risk of type 2 diabetes, possibly because of thei r greater central adiposity. The criteria for identifying individuals at ri sk of obesity-related conditions are usually not population specific. Objective: Our goal was to determine whether the National Heart, Lung, and Blood Institute (NHLBI) overweight and obesity guidelines are useful for id entifying diabetes risk in Japanese Americans. Design: This was a prospective, cohort study of 466 nondiabetic Japanese Am ericans [age: 52.2 +/- 0.6 y; BMI (in kg/m(2)): 24.1 +/- 0.2; (x) over bar +/- SEM]. Diabetes status at a 5-y follow-up visit was assessed with an ora l-glucose-tolerance test. Results: Among 240 subjects aged less than or equal to 55 y, incident diabe tes was strongly associated with overweight (BMI greater than or equal to 2 5) at baseline [relative risk (RR): 22.4; 95% CI: 2.7, 183; adjusted for ag e, sex, smoking, and family history] and weight gain of >10 kg since the ag e of 20 y (adjusted RR: 4.5; 95% CI: 1.4, 14.5). NHLBI definitions of centr al obesity (waist circumference greater than or equal to 88 cm for women an d greater than or equal to 102 cm for men) were unsuitable for this populat ion because only 15 of 240 subjects met these criteria. A waist circumferen ce greater than or equal to the third tertile was associated with diabetes (adjusted RR: 5.4; 95% CI: 1.7, 17.0). Among 226 subjects aged >55 y, incid ent diabetes was not associated with BMI, weight gain, or waist circumferen ce. Conclusions: NHLBI definitions are useful for identifying overweight Japane se Americans aged <55 y who are at high risk of diabetes. Although central adiposity is an important risk factor, the guidelines for waist circumferen ce are insensitive predictors of diabetes risk in this population.