Here’s a list of studies about vitamin D and migraine headaches:
The Prevalence of Headache May Be Related With the Latitude: A Possible Role of Vitamin D Insufficiency? (2010)
Conclusion: Study found that populations closer to the equator (where sun exposure, bright light exposure, and population vitamin D levels are the highest) have a noticeably lower prevalence of tension and migraine headaches compared to populations farther away from the equator.
Conclusion: There’s a very strong correlation between vitamin D deficiency and chronic migraine.
Conclusion: “Two postmenopausal migraineurs who developed frequent and excruciating migraine headaches (one following estrogen replacement therapy and the other following a stroke) were treated with combination vitamin D and calcium. Therapeutic replacement with vitamin D and calcium resulted in a dramatic reduction in the frequency and duration of their migraine headaches.”