These studies were designed as a dose-response meta-analysis of prospective studies, with trial sequential analysis to evaluate the available evidence for the relationship between magnesium supplementation and the risk of strokes. After review, the first study included seven prospective studies with 6477 cases of strokes and 241,378 total participants for analysis; while the second study included 15 studies. The results showed a modest but statistically significant inverse relationship between magnesium supplementation and the risk of stroke. This relation was observed with an increment of 100 mg per day of magnesium supplementation, which was associated with an 8% and 2% respective reduction in total stroke risk, especially ischemic strokes.
Larsson, S. C., Orsini, N., & Wolk, A. (2012). Dietary magnesium intake and risk of stroke: a meta-analysis of prospective studies. The American journal of clinical nutrition, 95(2), 362–366. https://doi.org/10.3945/ajcn.111.022376