Ischemic stroke risk and passive exposure to spouses' cigarette smoking. Melbourne Stroke Risk Factor Study (MERFS) Group.

OBJECTIVES: This study investigated the association between ischemic stroke risk and passive exposure to cigarette smoking.

METHODS: Risk factors among 452 hospitalized cases of first-episode ischemic stroke were compared with 452 age- and sex-matched "neighbor-hood" controls.

RESULTS: The risk of stroke was twice as high for subjects whose spouses smoked as for those whose spouses did not smoke (95% confidence interval = 1.3, 3.1), after adjustment for the subject's own smoking, heart disease, hypertension, diabetes, and education level. These results were confirmed when analysis was limited to those who never smoked.

CONCLUSIONS: These findings provide evidence that spousal smoking may be a significant risk factor for ischemic stroke.