Differential association of body mass index on glycemic control in type 1 diabetes.

Abstract

In contrast to type 2 diabetes, the association of body mass index (BMI) with glycemic control in type 1 diabetes (T1D) remains unclear. We investigated the relationship between BMI and average HbA1c levels in subjects with T1D. In this multi-centre observational study, we analysed 719 subjects with T1D aged ≥18years. Average HbA1c levels over 18months and other clinical and laboratory parameters were evaluated. The mean age and duration of diabetes at baseline were 41.5 ± 13.9 and 11.3 ± 8.7years, respectively. A U-shaped correlation between BMI and 18-month average HbA1c levels was documented by a spline curve. Based on this finding, subjects were divided into three groups according to BMI (group I, <21; group II, 21-23; and group III, ≥23kg/m2 ). In group I, the BMI negatively correlated with average HbA1c (r = -0.172, p = 0.011), while a positive relationship was observed (r = 0.162, p = 0.012) in group III. Average HbA1c levels were lower and the proportion of individuals with well-controlled glycemia (HbA1c <7%) were increased in the higher BMI tertile group among subjects with group I as well as in the lower BMI tertile group among subjects with group III BMI. After adjustment with additional covariates in the multiple regression model, these associations between BMI and HbA1c levels according to the different BMI ranges remained significant. In Korean subjects with T1D, an inverse relationship of BMI with HbA1c levels was observed in the low BMI group, while a positive correlation was shown in the high BMI group. Copyright © 2016 John Wiley & Sons, Ltd.