Pilz S et al. (2008) Low vitamin D levels predict stroke in patients referred to coronary angiography. Stroke [doi: 10.1161/STROKEAHA.107.513655]

Supplementation with vitamin D has been shown to have several positive effects in patients with stroke, including reducing osteopenia and fractures, and increasing muscle strength. A study conducted in Germany has now demonstrated an independent association between low levels of vitamin D and incidence of fatal stroke, which suggests that this vitamin could be directly protective against stroke.

The study was performed in 3,316 white patients referred for coronary angiography to a single center; serum concentrations of 25-hydroxyvitamin D (25[OH]D) were measured in 3,299 patients, and serum levels of 1,25-dihydroxyvitamin D (1,25[OH]2D) in 3,315 patients. Binary logistic-regression analyses demonstrated that levels of both 25(OH)D and 1,25(OH)2D were significantly lower in the 42 patients who died from stroke (27 ischemic, 8 hemorrhagic, and 7 of unknown etiology) during follow-up (median 7.75-years) than in study survivors. This relationship held true after adjustment for cardiovascular risk factors and levels of physical activity, calcium and parathyroid hormone. Additionally, levels of both vitamin D metabolites were reduced in patients with a baseline history of cardiovascular disease.

The authors acknowledge that the lack of a group of healthy controls in this study could have influenced the findings. Nevertheless, from the results of this study and those of a previous meta-analysis that indicated increased survival in individuals treated with vitamin D, they recommend that patients affected by or at high risk of stroke should receive vitamin D supplementation to maintain 25(OH)D concentrations of at least 75 nmol/l.