Background: Vitamin D has been associated with a variety of autoimmunity conditions including type 1 diabetes (T1D). Studies have indicated an increased prevalence of vitamin D deficiency in children with T1D.

Objective: The aim of our study was to examine vitamin D levels in a sample of children with type 1 diabetes in a primarily Hispanic population living in a sun rich location.

Materials and Methods: Results were obtained from a retrospective chart review in children (N = 350) diagnosed with T1D who had serum 25-hydroxyvitamin D [25(OH)D] level data available from a clinical visit (2008-2012). Vitamin D deficiency was defined as 25(OH)D level ≤ 50 nmol/L, and insufficiency ≤ 75 nmol/L. Obesity was defined as body mass index (BMI) >95% and overweight as BMI ≥85-≤95% for age and sex.

Results: The majority (64%) of our population was Hispanic [23.4% Non-Hispanic White (NHW), 12.6% Non-Hispanic Black (NHB)]. Mean age was 12.3 years (range 0.08-19.2 years). Mean BMI percentile for age was 66.1%, 19.3% were overweight and 12.7% obese. Mean 25(OH)D level was 72.9 nmol/L. Half of the sample was vitamin D insufficient (50.8%) and 11.7% were vitamin D deficient. Increasing age and BMI percentile were associated with lower 25(OH)D levels. Vitamin D was significantly lower among NHB compared to Hispanic and NHW.

Conclusions: Despite a sun rich environment, there was a high prevalence of vitamin D insufficiency in children with T1D, particularly among NHB subjects. Consistent with previous studies, hypovitaminosis D was inversely proportional to age and BMI. Compared to national data, children residing in a sun rich environment may have a decreased the risk of hypovitaminosis but the prevalence remains unexpectedly high.