Is the change in body mass index among children newly diagnosed with type 1 diabetes mellitus associated with obesity at transition from pediatric to adult care?

Background Insulin therapy is lifesaving treatment for individuals with type 1 diabetes ( T1D ). Its initiation maybe associated with significant weight gain because of change from a catabolic to an anabolic state. Excessive weight‐gain increases the risk of obesity and is associated with chronic disease. Objective To examine if change in body mass index ( BMI ) among children in the 6 months after diagnosis with type 1 diabetes mellitus is associated with long‐term obesity. Methods This was a population‐based retrospective study of 377 children (aged 2–18 yr) with type 1 diabetes. Measured heights and weights were used to calculate BMI z‐scores based on Centers for Disease Control and Prevention ( CDC ) cut‐points. Generalized Linear Models using BMI group, and age group at diagnosis; postdiagnosis weight change; and sex were applied to assess associations between postdiagnosis weight change and BMI z‐score at transition to adult care. Results Mean BMI z‐score increased from 0.28 at diagnosis, to 0.53 at 6 months and 0.66 at transition to adult care. Change in BMI z‐scores differed by initial BMI group and magnitude of postdiagnosis weight change. Younger children (<11 yr) had higher (p = 0.004) BMI z‐scores at diagnosis but not at last visit (p = 0.1) than older (≥11 yr) children at diagnosis. BMI z‐score at diagnosis, postdiagnosis weight change, female sex, and longer duration with TID were associated with higher BMI z‐score at time of transition. Conclusions BMI z‐score at diagnosis was the strongest predictor of BMI z‐score at time of transition to adult care, however; its effect was mediated by magnitude of weight change 6 months after diagnosis, sex, and age group at diagnosis.