Trajectories of Body Weight and Fat Mass in Relation to Incident Prediabetes in a Biracial Cohort of Free-Living Adults

OBJECTIVES: Obesity is a risk factor for type 2 diabetes (T2D), but prospective data relating adiposity measures to incident prediabetes are scant. METHODS: The Pathobiology of Prediabetes in A Biracial Cohort study followed normoglycemic African Americans (AA) and European Americans (EA) with parental history of T2D for the primary outcome of incident prediabetes (impaired fasting glucose and/or impaired glucose tolerance) for 5.5 years. Serial assessments included anthropometry and body fat composition. We analyzed weight, body mass index (BMI), waist, total, and abdominal fat mass in relation to incident prediabetes risk. RESULTS: Of the 376 subjects enrolled (217 AA, 159 EA; mean age 44.2 years, BMI 31.4 kg/m(2)), 343 (192 AA, 151 EA) had evaluable follow-up data. A total of 101 (52 AA, 49 EA) developed prediabetes during follow-up. Progressors to prediabetes had a mean baseline weight of 90.0 ± 20.4 kg versus 82.9 ± 21.7 kg among nonprogressors (P = 0.0036). During 5.5 (mean 2.62) years of follow-up, the weight change among nonprogressors was 0.63 ± 6.11 kg compared with 2.54 ± 6.91 kg among progressors (ANOVA P = 0.0072). Progressors also showed greater increases in total fat (P = 0.0015) and trunk fat (P = 0.0005) mass than nonprogressors. Adjusted for age and sex, the significant predictors of incident prediabetes were BMI (P = 0.0013), waist (P < 0.0001), total fat (P = 0.0025), and trunk fat (P < 0.0001) mass. CONCLUSIONS: Among obese free-living offspring of parents with T2D, long-term normoglycemic status was associated with a weight gain of ~0.2 kg/y, whereas progression to prediabetes was associated with a weight gain of ~1 kg/y.