Alcohol as a risk factor for hemorrhagic stroke.

PURPOSE: Whereas the protective effect of mild-to-moderate alcohol consumption against ischemic stroke has been well recognized, there is conflicting evidence regarding the link between alcohol consumption and hemorrhagic strokes. The aim of the present study is to summarize the results of case-control and cohort studies published on this issue. METHODS: Recent epidemiologic articles on the relationship between alcohol consumption and hemorrhagic stroke were identified by Medline searches limited to title words using the following search terms: "alcohol AND cerebrovascular dis*", "alcohol AND stroke", "alcohol AND cerebral hemorrhage" and "alcohol AND hemorrhagic stroke". RESULTS: Most case-control and cohort studies either reported only on total strokes or on a combined group of hemorrhagic strokes including intracerebral as well as subarachnoid hemorrhages. There was a consensus among reports that heavy alcohol consumption was associated with a higher risk of hemorrhagic strokes. Controversy remains regarding the effect of mild-to-moderate alcohol consumption: while some studies reported a protective effect, others found a dose-dependent linear relationship between the amount of alcohol consumed and the risk of hemorrhagic stroke. The differential effect of moderate alcohol consumption on hemorrhagic compared to ischemic strokes is mostly attributed to alcohol- and withdrawal-induced sudden elevations of blood pressure, and coagulation disorders. CONCLUSIONS: Heavy drinking should be considered as one of the risk factors for hemorrhagic stroke. In contrast to the protective effect of mild-to-moderate alcohol use against ischemic strokes, moderate drinking might result in an increased risk of hemorrhagic strokes.