25-Hydroxyvitamin D and glycemic control: A cross-sectional study of children and adolescents with type 1 diabetes

•To our knowledge this is the first study that has been adequately-powered to examine the association between 25-hydroxyvitamin D and HbA1c in children and adolescents with T1DM.•The association between 25-hydroxyvitamin D and HbA1c was not positive, calling for longitudinal studies to confirm these findings.•This study demonstrated the high prevalence of patients with low levels of 25-hydroxyvitamin D specifically in healthy weight and Caucasian children and adolescents with T1DM.•These data suggest the need for monitoring of 25-hydroxyvitamin D in all youth with T1DM.

AimThe objective of this study was to describe the vitamin D status of children and adolescents with type 1 diabetes and to evaluate whether levels of 25-hydroxyvitamin D are significantly associated with HbA1c in this population.Methods197 children and adolescents from a diabetes center in a children's hospital were recruited during regular follow up visit. Non-fasting blood samples were collected to measure 25-hydroxyvitamin D and blood glucose levels. HbA1c and other key variables were abstracted from patients' medical records.ResultsOf the 197 children and adolescents, more than half were adolescents, males, and Caucasian. 23% were overweight, while 13% were obese. Mean HbA1c was 8.6 ± 1.4% (70 ± 15.3 mmol/mol). 40.6% of patients had 25-hydroxyvitamin D levels ≤50 nmol/L; 49.2% had 25-hydroxyvitamin D levels between 51 and 75 nmol/L and 10.2% had 25-hydroxyvitamin D levels >75 nmol/L. The bivariate relationship between 25-hydroxyvitamin D and HbA1c almost reached statistical significance (P = 0.057), while no significance was established in the multivariate model.ConclusionsTo the best of our knowledge this is the first study that has been adequately-powered to examine the association between 25-hydroxyvitamin D and HbA1c in children and adolescents with T1DM. This study demonstrated the high prevalence of patients with low levels of 25-hydroxyvitamin D specifically in healthy weight and Caucasian children and adolescents with T1DM. These data suggest the need for monitoring of 25-hydroxyvitamin D in all youth with T1DM.