Vitamin D Deficiency and Atopic Dermatitis: Consider Disease, Race, and Body Mass.

Vitamin D deficiency causes rickets, but has been associated with various diseases, including atopic dermatitis (AD). This study analyzes serum vitamin D in pediatric medical center patients with AD and potential confounding factors. At Cardinal Glennon Children's Hospital, charts of 665 children with serum 25-hydroxyvitamin D levels taken between 2009 and 2013 were retrospectively reviewed. Defining vitamin D deficiency as <20 ng/mL, neither average 25-hydroxyvitamin D nor deficiency prevalence varied among disease groups, except for cystic fibrosis (CF), which demonstrated significantly higher average vitamin D and lower deficiency prevalence. Children with AD had the lowest prevalence of vitamin D sufficiency, without significant association with disease severity. No seasonal variation was detected. Strong correlations were observed between 25-hydroxyvitamin D levels, body mass index (BMI), and race. Our data showed no strong association between vitamin D levels and AD or AD severity. A strong association was noted between skin type and BMI. The lower prevalence of vitamin D deficiency among children with CF may be explained by lighter skin and lower BMI. A high prevalence of vitamin D insufficiency and deficiency as currently defined among children with dark skin and high BMI suggests a need to reevaluate normal vitamin D levels in these populations.