Maximum BMI and microvascular complications in a cohort of Japanese patients with type 2 diabetes: the Japan Diabetes Complications Study.

<bold>Aims: </bold>The aim of this study was to examine the associations between possible indices of obesity based on information on weight history and the incidence of microvascular complications.<bold>Methods: </bold>A cohort of individuals with type 2 diabetes from 59 institutes in Japan was followed for 8years. Patients were classified into three categories according to weight at entrance and past maximum weight: normal (BMI at baseline <25kg/m(2) and maximum BMI <25kg/m(2)), past obesity (BMI at baseline <25kg/m(2) and maximum BMI ≥25kg/m(2)), and current obesity (BMI at baseline ≥25kg/m(2)) groups. The outcomes were diabetic retinopathy and overt nephropathy.<bold>Results: </bold>BMI at maximum and baseline of the 1809 patients was 26.5±3.5 and 23.1±3.0kg/m(2) (p<0.01), respectively (23.0±1.6 and 20.6±1.9kg/m(2) for normal, 27.4±2.0 and 22.8±1.4kg/m(2) for past obesity, and 30.1±2.9 and 27.0±1.8kg/m(2) for current obesity). The hazard ratios of past and current obesity compared to normal were 1.92 (95% CI, 1.08-3.41; p=0.03) and 2.21 (1.16-4.22; p=0.02), respectively, for overt nephropathy and 1.38 (1.05-1.83; p=0.02) and 1.64 (1.18-2.28; p<0.01), respectively, for diabetic retinopathy after adjustment for confounders.<bold>Conclusions: </bold>Past obesity as well as current obesity were associated with increased risks of microvascular complications. Further identification of high-risk populations may be possible by classifying normal weight patients by past obesity. [ABSTRACT FROM AUTHOR]