Patterns in Body Mass Index Changes in Children after Type 1 Diabetes Mellitus Diagnosis.

Background: Pediatric patients with newly diagnosed type 1 diabetes mellitus (T1DM) are commonly treated with daily multiple insulin injections or an insulin pump. They tend to have higher body mass index-standard deviation scores (BMI-SDS) than non-diabetic children.

Objectives: To identify patterns in the changes in BMI in the 3 years after T1DM diagnosis, and to discover factors that relate to excessive weight gain.

Methods: This retrospective study included clinical and laboratory data for 194 boys and girls aged 2-18 years at the time of diagnosis and at 1, 2, and 3 years after. Their BMI values were compared to non-diabetic children using BMI percentile and z-score (standard deviation) based on the U.S. Centers for Disease Control and Prevention (CDC) growth charts.

Results: Both males and females had low mean BMI-SDS at diagnosis (-0.4499 ± 1.38743 male, 0.3050 ± 1.29887 female) that increased after 1 year (-0.0449 ± 1.14772 male, 0.1451 ± 0.98893 female). Lower glycated hemoglobin (HbA1c) at 1 year correlated with higher BMI-SDS (r = -0.215, P = 0.011). No such correlation was found in the following 2 years. The daily dose of basal insulin correlated with higher BMI-SDS at 1 year (r = 0.183, P = 0.026) and 3 years (r = 0.297, P < 0.01). No association was found between the use of an insulin pump or continuous glucose monitoring and higher BMI-SDS.

Conclusions: BMI-SDS of children with T1DM was lower than average at the time of diagnosis and rose higher than average in the 3 years following. Higher BMI-SDS was not significantly associated with sex or ethnicity. The most prominent increase happened in the first year.