Observational studies have suggested a complex relationship between alcohol consumption and stroke, dependent on sex, type of stroke and outcome (morbidity vs. mortality). Researchers undertook a systematic review and a meta-analysis of studies assessing the association between levels of average alcohol consumption and relative risks of ischemic and hemorrhagic strokes separately by sex and outcome. This meta-analysis is the first to explicitly separate morbidity and mortality of alcohol-attributable stroke and thus has implications for public health and prevention.
Data was drawn from twenty-six observational studies (cohort or case-control) with ischemic or hemorrhagic strokes where the relative risk or odds ratios or hazard ratios of stroke associated with alcohol consumption were reported; alcohol consumption was quantified; and life time abstention was used as the reference group.
The dose-response relationship for hemorrhagic stroke had monotonically increasing risk for increasing consumption, whereas ischemic stroke showed a curvilinear relationship, with a protective effect of alcohol for low to moderate consumption, and increased risk for higher exposure. For more than 3 drinks on average/day, in general women had higher risks than men, and the risks for mortality were higher compared to the risks for morbidity.
The authors conclude that heavy alcohol consumption (above 30g per day) increases the relative risk of any stroke while light or moderate alcohol consumption may be protective against ischemic stroke.
Source: Alcohol consumption and the risk of morbidity and mortality for different stroke types – a systematic review and meta-analysis. Patra J; Taylor B; Irving H; Roerecke M; Baliunas D; Mohapatra S; Rehm J. BMC Public Health vol 10, art No 258, 2010, 12pp