Determination of serum 25-hydroxyvitamin D levels in patients with alopecia areata and their comparison with levels in healthy controls: A cross-sectional study

Alopecia areata (AA) has been postulated to be an autoimmune disease affecting the hair follicles. Because vitamin D receptors are present in the immune system and hair follicles, vitamin D has been hypothesized to affect the disease. The aim of this study was to determine serum 25-hydroxyvitamin D levels and the percentage of vitamin D deficiency in AA patients and compare them with those in healthy controls in a Philippine tertiary hospital. This cross-sectional study included 29 AA patients and 29 healthy controls. The serum 25-hydroxyvitamin D levels were determined using the chemiluminescent immunoassay method. There was no significant difference in the mean vitamin D levels between AA patients (24.41 ± 6.87 ng/mL) and healthy controls (24.68 ± 6.68 ng/mL) ( P  = .88). The percentage of patients with vitamin D deficiency, defined as <20 ng/mL, trended to higher among AA patients (34.4%) than among healthy controls (17.2%), with an odds ratio of 2.53 (95% CI 0.73-8.65), though this was not statsitically significant. This study involved a limited number of patients in an urbanized area in the Philippines, and majority of the AA cases seen had mild AA. The trend toward the increased percentage of vitamin D-deficient individuals among AA patients seen in this study may provide insight into the association of vitamin D with AA.