Sun-induced migraine attacks in an Arctic population

Aims: The main purpose of the study was to evaluate the impact of weather, and especially sun exposure, on migraine. Methods: Data from a previous prospective 12-month diary study was compared with meteorological data. We retrospectively evaluated 1250 migraine attacks recorded by a group of 40 women with a mean age of 37.1 years who fulfilled the IHS criteria for migraine with and without aura. Results: The patients reported more sun-induced migraine attacks on sunny days, but the total distribution of migraine attacks was constant throughout the year. Also, no seasonal variation of migraine, nor any relationships between weather parameters and onset of migraine attacks, were found. An analysis of a subgroup of patients with 'sun-induced' migraine showed a significant increase in frequency of migraine attacks in the summer compared to the winter (p = 0.04). Conclusion: This study confirms that sunlight might be a trigger for migraine, but a risk for increased impact of light on the total ailment of migraine headache should be searched for in a subgroup of sensitive migraineurs.