Lower Vitamin D Intake — 27% Greater Risk Of Thromboembolic Stroke

An article published on May 24, 2012 in the American Heart Association journal Stroke reports a protective effect for greater vitamin D intake against the risk of ischemic stroke in Japanese-American men. To the authors' knowledge, there has only been one other longitudinal cohort study (which had fewer subjects and a shorter follow-up) that evaluated dietary vitamin D intake and stroke risk.

Gotaro Kojima, MD of the University of Hawaii and colleagues utilized data obtained from 7,385 Japanese-American men residing in Oahu who were between the ages of 45 to 68 upon enrolling in the Honolulu Heart Program between 1965 and 1968. Dietary recall interviews conducted upon enrollment were analyzed for the intake of vitamin D from food. (The authors note that regular use of dietary supplements was uncommon in the 1960s.)

Over the 34-year follow-up period, stroke was documented in 960 subjects. For men whose vitamin D intake was among the lowest 25 percent of participants, the adjusted risk of stroke was 22 percent higher than the risk experienced by those whose intake was among the top 25 percent. When stroke was analyzed by type, the risk of thromboembolic stroke was 27 percent higher for those whose vitamin D intake was lowest in comparison with the highest group, and no significant association was found between the vitamin and the risk of hemorrhagic stroke.