Glycemic control and variability in association with body mass index and body composition over 18 months in youth with type 1 diabetes

Aims: The impact of adiposity on glycemic control in type 1 diabetes patients has important implications for preventing complications. This study examined associations of glycemic outcomes with body mass index (BMI, kg/m(2)) and body composition in youth with type 1 diabetes. Methods: This is a secondary analysis of an 18-month randomized controlled dietary intervention trial (N = 136, baseline age = 12.3 +/- 2.5 y, HbA1c = 8.1 +/- 1.0% (65 +/- 11 mmol/mol)). Measured height and weight every 3 months were abstracted from medical records. Body composition was assessed by dual energy X-ray absorptiometry (DXA) at baseline, 12 and 18 months. Glycated hemoglobin (HbA1c) and glycemic variability assessed by masked 3-day continuous blood glucose monitoring (CGM) were obtained every 3 months. 1,5-Anhydroglucitol (1,5-AG) was assessed every 6 months. Adjusted random effects models for repeated measures estimated associations of time-varying BMI and body composition with time-varying glycemic outcomes. Results: There was no treatment effect on glycemic outcomes. HbA1c was not associated with BMI or body composition indicators. 1,5-AG was inversely associated with BMI and adiposity indicators (% fat, trunk fat mass and trunk % fat), adjusting for developmental covariates. Adiposity indicators were positively associated with % glucose > 180 mg/dL and > 126 mg/dL when adjusting for developmental covariates, and % glucose > 126 mg/dL when additionally adjusting for diabetes-related covariates. Fewer consistent relationships were observed for 3-day mean glucose and % glucose < 70.2 mg/dL. BMI and body composition variables were not associated with standard deviation of glycemic values or mean amplitude of glycemic excursions. Conclusions: The role of greater BMI and adiposity in diabetes management in youth with type 1 diabetes may relate specifically to increased hyperglycemic excursions. Published by Elsevier Ireland Ltd.