Serum 25 hydroxyvitamin D levels in alopecia areata, female pattern hair loss, and male androgenetic alopecia in a Chinese population.

BACKGROUND: It has been suggested that low vitamin D levels may affect the development of hair loss. AIMS: Our aim was to evaluate the serum 25-hydroxy vitamin D [25(OH)D] status in Chinese patients with alopecia areata (AA), female pattern hair loss (FPHL), and male androgenetic alopecia (MAGA) compared with healthy individuals. METHODS: We performed a case-control study including 443 AA patients, 657 FPHL patients, 777 MAGA patients, and 2070 normal controls (1064 male and 1006 female healthy individuals) from 2015 to 2017 to analyze the correlation of serum 25(OH)D levels and hair loss in a Chinese population. RESULTS: Serum 25(OH)D levels stratified by age, sex, and season were compared between patients and healthy individuals. AA patients' serum 25(OH)D levels were statistically lower than that of controls (P < .0001, α = .05). Serum 25(OH)D levels of FPHL patients (P < .0001, α = .05) and MAGA patients (P = .0005, α = .05) were also significantly lower than counterpart control subjects. CONCLUSION: Our findings suggest an association between serum 25(OH)D levels and alopecia areata, female pattern hair loss, or male androgenetic alopecia in a Chinese population.