Introduction: Limited data regarding predictors of vitamin D deficiency in US children exist. We aimed to identify predictors of vitamin D insufficiency among children with alopecia areata.

Methods: The medical records of 439 pediatric patients diagnosed with alopecia areata (AA) between January 2015 and December 2017 were reviewed. Those with 25-hydroxyvitamin D levels and no documented vitamin supplementation, chronic illness, or other autoimmune comorbidities other than AA were included. Demographic data, Fitzpatrick skin type, and the month of blood collection were recorded. Monthly UV index information from Philadelphia, PA corresponding to the month of blood collection was also collected.

Results: Within our cohort, 60.4% of patients had insufficient vitamin D levels, of which 38.2% were deficient. The mean age was nine years old. In multivariate analyses, higher Fitzpatrick skin type, non-summer season, and non-White race were associated with vitamin D insufficiency, while the monthly UV index was inversely associated.

Discussion/conclusion: Higher Fitzpatrick skin type, non-summer season, and non-White race may be associated with vitamin D insufficiency in US pediatric patients. Larger studies are warranted to replicate our findings and fully evaluate predictors of pediatric vitamin D deficiency in the US.