Body mass index changes in youth in the first year after type 1 diabetes diagnosis

To describe changes in weight and body mass index (BMI) during the first year following diagnosis of type 1 diabetes (T1D) and associations with demographic and clinical characteristics.

The Pediatric Diabetes Consortium includes 7 US centers with prospective longitudinal data from initial T1D diagnosis. This analysis includes 530 youth with diabetes duration of ≥1 year and measures of BMI at 3 and 12 months after diagnosis. BMI trajectory of participants and relationships between the change in BMI z-score from baseline (3 months) to 12 months with demographic characteristics, hemoglobin A1c at baseline, and insulin delivery mode at baseline were evaluated.

As a group, BMI z-scores increased sharply from diagnosis for 1-3 months but remained relatively stable from +0.51 at 3 months to +0.48 at 12 months. Children aged 2-<5 years experienced a significant positive change in BMI z-score between 3 and 12 months, and there was a similar trend among girls that did not reach statistical significance. No significant differences were found for race, socioeconomic status, or insulin delivery mode.

These data suggest that increased BMI during the first year of treatment of most youth with T1D reflects regain of weight lost before diagnosis. There is, however, a propensity toward additional weight gain in younger children and girls.