Vitamin D Abnormalities: More Common in US Children with T1D than in Healthy Children

Abstract

Background: Pediatric patients with type 1 diabetes (T1D) have increased risk for low bone mineral density, which may be due in part to low 25-hydroxyvitamin D levels. Vitamin D levels are influenced by sunlight exposure and thus display geographical variation. We hypothesize that the prevalence of 25-hydroxyvitamin D deficiency (<20 ng/mL) and insufficiency (20 - 29 ng/mL) in children with T1D living in the United States is higher than in healthy children and that diabetes duration, HbA1c, and insulin dose/kg are inversely associated with 25-hydroxyvitamin D levels. Methods: Medical records of patients with T1D being followed in Tennessee were reviewed for demographics, medical information, and 25-hydroxyvitamin D levels during the previous 2 years. Control subjects were obtained from a de-identified database of healthy pediatric subjects living in a similar geographical area. Chi squared tests and multivariable linear regression were performed. Results: Children and adolescents with T1D (n = 276; median age 14 years) have a significantly higher percentage of vitamin D deficiency and insufficiency compared with healthy pediatric controls (n = 100; median age 11.2 years) (68% versus 44%; p < 0.001). The median 25-hydroxyvitamin D level is 24 ng/mL versus 31 ng/mL, respectively. After adjusting for age, race, gender, UV light exposure, BMI, and multivitamin supplementation, children and adolescents with T1D have a serum 25-hydroxyvitamin D level 6.7 ng/mL lower than the control population [CI(4.11, 9.21), p < 0.0001]. Within the T1D population, there is no clear association between diabetes duration, HbA1c, or insulin dose/kg and 25-hydroxyvitamin D levels. Conclusions: There is an increased prevalence of 25-hydroxyvitamin D deficiency and insufficiency in US. children with T1D compared with geographically similar children without diabetes. Further research is needed to determine whether decreased serum 25-hydroxyvitamin D can be alleviated via dietary or behavioral modifications in this population.