Diabetes Risk Among Overweight and Obese Metabolically Healthy Young Adults

OBJECTIVE To determine diabetes incidence over time among obese young adults without metabolic risk factors. RESEARCH DESIGN AND METHODS Incident diabetes during a median follow-up of 6.1 years was assessed among 33,939 young men (mean age 30.9 +/- 5.2 years) of the Metabolic, Lifestyle and Nutrition Assessment in Young Adults cohort who were stratified for BMI and the number of metabolic abnormalities (based on the Adult Treatment Panel-III). Metabolically healthy (MH) obesity was defined as BMI >= 30 kg/m(2) in the presence of normoglycemia, normal blood pressure, and normal levels of fasting triglyceride and HDL-cholesterol levels (n = 631). RESULTS A total of 734 new cases of diabetes were diagnosed during 210,282 person-years of follow-up. The incidence rate of diabetes among participants with no metabolic risk factors was 1.15, 2.10, and 4.34 cases per 1,000 person-years among lean, overweight, and obese participants, respectively. In a multivariable model adjusted for age, region of origin, family history of diabetes, physical activity, fasting plasma glucose, triglyceride level, HDL-cholesterol, systolic blood pressure, and white blood cell count, a higher diabetes risk was observed among MH-overweight (hazard ratio [HR] 1.89 [95% CI 1.25-2.86]; P < 0.001) and MH-obese (HR 3.88 [95% CI 1.94-7.77]; P < 0.001) compared with MH-normal weight subjects. There was no interaction between BMI and the number of metabolic abnormalities at enrollment in predicting diabetes risk. CONCLUSIONS Healthy metabolic profile and the absence of diabetes risk factors do not protect young adults from incident diabetes associated with overweight and obesity.