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

• Adiposity indicators were not associated with HbA1c or hypoglycemia.
• BMI was not associated with HbA1c or glycemic variability.
• Greater BMI and adiposity were associated with lower 1,5-anhydroglucitol.
• Adiposity indicators were positively associated with hyperglycemia.

AimsThe 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/m2) and body composition in youth with type 1 diabetes.MethodsThis 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.ResultsThere 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.ConclusionsThe role of greater BMI and adiposity in diabetes management in youth with type 1 diabetes may relate specifically to increased hyperglycemic excursions.