Alcohol intake and the risk of stroke

Alcohol consumption has been reported to have both beneficial and harmful e ffects on the incidence of stroke, Different drinking habits may explain th e diversity of the observations, but this is still unclear. We reviewed rec ent clinical and epidemiological studies to iind out whether alcohol intake could increase or decrease the risk for stroke. By a systematic survey of literature published from 1989 to 1997, we identified 14 case-control studi es addressing alcohol as a risk factor for haemorrhagic and ischaemic strok e morbidity and fulfilling the following criteria: the type of stroke was d etermined by a head computerised tomography scan on admission or at autopsy ; and alcohol consumption was verified using structured questionnaires or b y personal interviews. In some studies, adjustment for hypertension abolish ed the independent role of alcohol as a risk factor: On the other hand, the studies covering even recent alcohol intake showed in many cases that heav y drinking is an independent risk factor for most stroke subtypes, and that the risk may decrease relatively rapidly after the cessation of alcohol ab use. In some studies, regular light to moderate drinking seemed to be assoc iated with a decreased risk for ischaemic stroke of atherothrombotic origin . In conclusion, recent heavy alcohol intake seems to be an independent ris k factor for ail major subtypes of stroke, The ultimate mechanisms leading to the increased risk are unclear. The significance of alcohol as a risk fa ctor has been demonstrated in young subjects because they are more often he avy drinkers than the elderly. Several factors to explain the beneficial ef fect of light to moderate drinking have been proposed. (C) 1999 Lippincott Williams & Wilkins.