Hussein M, et al. - Researchers investigated how patients with migraine differ from healthy control participants with respect to serum levels of 25 (OH)-vitamin D, and how headache characteristics differ according to vitamin D status. The also assessed how serum 25 (OH)-vitamin D level is correlated with duration, frequency, and severity of migraine headache attacks. In this case-control study involving 40 patients with migraine and 40 healthy control participants, they observed significantly lower 25(OH)-vitamin D serum level among patients with migraine vs control participants. Migraineurs with vitamin D deficiency vs those with normal vitamin D had a significantly higher incidence of aura, phonophobia/photophobia, autonomic manifestations, allodynia, and resistance to medications. Furthermore, 25(OH)-vitamin D serum level had a statistically significant negative correlation with attack duration in hours, frequency of the attacks/month, migraine severity scale, and Headache Impact Test-6 scale.