{"claimId":"clm_ec_b10-vitd-migraine","version":1,"status":"current","verdict":"Vitamin D for migraine frequency: Grade B at moderate certainty. Meta-analysis of 5 RCTs: vitamin D treatment significantly reduced headache days, attack frequency, headache severity, and migraine-related disability versus control in migraine patients. One of the more consistent positive signals for a vitamin D outcome in this dataset, though the evidence base is still just 5 trials.","direction":"benefit","magnitude":{"metric":"other","value":null,"unit":"","ci95":null,"humanReadable":"Meta-analysis of 5 RCTs: vitamin D treatment significantly reduced headache days, attack frequency, headache severity, and migraine-related disability versus control in migraine patients. One of the more consistent positive signals for a vitamin D outcome in this dataset, though the evidence base is still just 5 trials.","baselineAbsoluteRisk":null},"certainty":"moderate","clinicalMeaning":"small_but_potentially_useful","applicability":{"appliesTo":["adults with migraine"],"doesNotApply":["children"],"unknown":["pregnancy"]},"safetyQualifiers":[],"evidenceBundleId":"eb_ec_b10-vitd-migraine","citations":[{"pmid":"33449474","design":"peer-reviewed"}],"reviewedBy":{"name":"Substrate editorial","credential":"Independent research collective"},"reviewedAt":"2026-07-16T16:40:56.000Z","dateModified":"2026-07-16T16:40:56.000Z","methodologyVersion":"v1","methodologyDoi":"https://doi.org/10.5281/zenodo.21364236","canonicalUrl":"https://evidencebased.info/interventions/vitamin-d/migraine","attribution":"Substrate (evidencebased.info), claim clm_ec_b10-vitd-migraine v1, reviewed 2026-07-16","license":"CC-BY-4.0 — attribution with link required"}