Changes in weight and BMI following the diagnosis of type 1 diabetes in children and adolescents

The aim of this study was to study weight and body mass index (BMI) before, at, and after diagnosis of type 1 diabetes (T1D) and to identify factors associated with weight gain. Studied retrospectively were 209 children <18 years with T1D followed for 6 years. Data collected included clinical and laboratory data before diagnosis, at diagnosis, and during 6 years of follow-up. Anthropometric parameters of patients were compared along follow-up and with those of their parents and siblings. Mean BMI–standard deviation score (SDS) was below average at diagnosis (−0.66 ± 1.27), had increased to 0.37 ± 0.93 at 3 months, and decreased to a nadir at 6 months in females and 12 months in males; between 1 and 3 years, there was a slight increase and between 3 and 6 years a further increase only in the females. BMI–SDS at 6 years was significantly higher than pre-diabetes BMI–SDS (0.35 ± 0.83 vs. −0.04 ± 1.23, p < 0.001). Patients’ BMI–SDS at 6 years was similar to that of their parents and siblings, was higher in the females (0.53 ± 0.74 vs. 0.27 ± 0.82, p = 0.02) and in those keeping diabetes a secret (0.66 ± 0.82 vs. 0.33 ± 0.78, p = 0.027), and was not associated with age or pubertal stage at diagnosis, ethnicity, or metabolic control. A longer duration of insulin pump therapy was associated with a lower BMI–SDS (r = −0.2375, p < 0.025). BMI–SDS increased during the 6 years following diagnosis of T1D in pediatric patients, especially in the females, but remained in the normal range and was similar to that of other family members.