Multivitamin use and risk of stroke mortality: the Japan collaborative cohort study.

BACKGROUND AND PURPOSE: An effect of multivitamin supplement on stroke risk is uncertain. We aimed to examine the association between multivitamin use and risk of death from stroke and its subtypes.

METHODS: A total of 72 180 Japanese men and women free from cardiovascular diseases and cancers at baseline in 1988 to 1990 were followed up until December 31, 2009. Lifestyles including multivitamin use were collected using self-administered questionnaires. Cox proportional hazards regression models were used to estimate hazard ratios (HRs) of total stroke and its subtypes in relation to multivitamin use.

RESULTS: During a median follow-up of 19.1 years, we identified 2087 deaths from stroke, including 1148 ischemic strokes and 877 hemorrhagic strokes. After adjustment for potential confounders, multivitamin use was associated with lower but borderline significant risk of death from total stroke (HR, 0.87; 95% confidence interval, 0.76-1.01), primarily ischemic stroke (HR, 0.80; 95% confidence interval, 0.63-1.01), but not hemorrhagic stroke (HR, 0.96; 95% confidence interval, 0.78-1.18). In a subgroup analysis, there was a significant association between multivitamin use and lower risk of mortality from total stroke among people with fruit and vegetable intake <3 times/d (HR, 0.80; 95% confidence interval, 0.65-0.98). That association seemed to be more evident among regular users than casual users. Similar results were found for ischemic stroke.

CONCLUSIONS: Multivitamin use, particularly frequent use, was associated with reduced risk of total and ischemic stroke mortality among Japanese people with lower intake of fruits and vegetables.