Endocrine Abstracts

JOINT796

Introduction: Glycemic control in type 1 diabetes is known to worsen significantly during adolescence and young adulthood. Female sex is known to be a risk factor for this worsening glycemic control, but the mechanisms of this are unclear. We hypothesized that body mass index (BMI) may be a factor that facilitates worsening A1C in female youth.

Methods: We have previously established the British Columbia Pediatric Diabetes Registry (BC-PDR). Using this registry, we graphed the trajectory of A1C by age according to sex. We conducted this same analysis stratifying by BMI categories: underweight/normal weight, overweight, and obese. Using regression modelling, we compared average A1C between the sex-BMI categories for each age, adjusting for total daily dose of insulin and presence of chronic comorbidities. Missing data was addressed with multiple imputation.

Results: There were 674 patients with type 1 diabetes diagnosed in childhood and adolescence from the BC-PDR who were included in this study (299 females and 375 males). At recruitment, 35. 5% of females and 31. 7% of males were in the overweight or obese BMI category. At age 7, the average A1C of underweight/normal weight males was 7. 53%, which was not significantly different compared to the average A1C of overweight males, obese males, and females of any BMI category. However, by age 17, there were significant differences in average A1C between the different sex-BMI categories. At this age, the average A1C of underweight/normal weight males was 8. 16%, but average A1C was 0. 84% lower (95% CI -1. 10, -0. 59, P < 0. 001) in overweight males and 0. 94% lower (95% CI -1. 21, -0. 68, P < 0. 001) in obese males. The average A1C of underweight/normal weight females was not significantly different from that of underweight/normal weight males (+0. 15%, 95% CI -0. 04, 0. 34, P = 0. 118), but was 0. 78% higher (95% CI 0. 53, 1. 03, P < 0. 001) in overweight females and 0. 35% higher (95% CI 0. 15, 0. 55, P = 0. 001) in obese females.

Conclusions: There appears to be a differential effect of sex and BMI on A1C amongst adolescents with type 1 diabetes. Average A1C is highest amongst adolescent females who are in the overweight and obese BMI categories. These findings suggest that weight management (e. g. including the use of weight loss adjuncts), particularly in overweight and obese post-pubertal females, may be an important treatment modality for adolescents with type 1 diabetes. Further study is needed to determine the factors and mechanisms, whether biological or psychological, that contribute to elevated A1C amongst female youth living with type 1 diabetes.