effect of vitamin d supplementation on symptoms and c-reactive protein in migraine patients

background: migarine is the most common headache around the world including iran. in recent years, vitamin d deficiency has been shown to a global health problem. a few studies have been determined inverse association between serum levels of vitamin d with a headache. so, in this study, we investigated the effect of vitamin d supplementation on symptoms and c-reactive protein(crp) among patients with migraine. materials and methods: this study was randomized, double-blind, and controlled-placebo clinical trial. sixty-five migraine patients aged 10-61 years were included for analysis. vitamin d was administrated for 10 weeks with 50,000 iu dosage of vitamin d per week. multivariate analysis of covariate and univariate analysis of covariate were done to determine the effects of vitamin d supplementation on symptoms, including severity, duration, frequency of headache, and the headache diary result (hdr). results: mean headache frequency and hdr had significant difference among two groups (5.9 ± 7.0  vs. 7.0 ± 6.0, p = 0.06 and 85.0 ± 134.2 vs. 132.1 ± 147.1, p = 0.04). but, a mean difference of headache frequency was marginally significant (p = 0.06). these values were lower among the intervention group compared to placebo group. the association was not observed between crp with migraine disease. conclusion: in this study, we shown vitamin d supplementation may be useful in decreasing frequency of headache attacks and hdr among patients with migraine.