Trajectories of Body Mass Index from Childhood to Young Adulthood among Patients with Type 1 Diabetes—A Longitudinal Group-Based Modeling Approach Based on the DPV Registry

To identify distinct longitudinal patterns of body mass index (BMI) z score in type 1 diabetes from childhood to young adulthood and secondly to determine sex differences as well as associated clinical covariates. A total of 5665 patients with type 1 diabetes (51% male) with follow-up from 8 to 20 years of age from the multicenter diabetes prospective registry DPV were studied (baseline diabetes duration ≥1 years, BMI z score aggregated per year of life). Latent class growth modeling (SAS: PROC TRAJ) was applied to analyze BMI z score over time. Six distinct BMI z score trajectories were identified (group 1: 7% of patients, group 2: 22%, group 3: 20%, group 4: 16%, group 5: 25%, and group 6: 10%). Group 1, 2, 5, and 6 had an almost stable BMI z score, either in the low, near-normal, high stable, or chronic overweight range. Group 3 (60% girls) increased their BMI during puberty, whereas group 4 (65% boys) had a BMI decrease. Similar patterns were observed for girls only, whereas boys followed nearly stable trajectories without fluctuation over time. Between the near-normal and the other groups, significant differences (P