Background and purpose: Epidemiological evidence suggests that heavy alcohol consumption increases the risk for ischemic stroke, whereas light-to-moderate alcohol intake decreases the risk, but the role of different drinking patterns has remained unclear. We investigated recent light, moderate, and heavy alcohol drinking and former heavy drinking as risk factors for acute ischemic brain infarction by etiological subtype of stroke.
Methods: We compared 212 consecutive patients aged between 16 and 60 years, who were completely evaluated for the etiology of their ischemic stroke, with 274 control subjects admitted to the emergency unit of the same hospital. ORs, as estimates of multivariate relative risks (RRs), and 95% CIs after adjustment for possible confounding variables were calculated by logistic regression. The ORs were adjusted for age, sex, body mass index, hypertension, diabetes, hyperlipemia, current smoking, and history of migraine.
Results: Recent heavy drinking but not former heavy drinking was an independent risk factor for stroke (RR 1.82, 95% CI 1.08 to 3.05). Consumption of 151 to 300 g and >300 g alcohol within the week preceding the onset of stroke significantly increased the risk for cardioembolic and cryptogenic stroke. Consumption of >40 g alcohol within the preceding 24 hours increased the risk for cardiogenic embolism to the brain among those who had a high-risk source (RR 4.75, 95% CI 1.23 to 18.4), the risk for tandem embolism among those who had prominent large-artery atherosclerosis (RR 7.68, 95% CI 1.82 to 32.3), and the risk for cryptogenic stroke (RR 3.84, 95% CI 1.69 to 8.71). Light drinking did not increase the risk for stroke.
Conclusions: We conclude that acute drinking of intoxicating amounts of alcohol may trigger the onset of embolic stroke among subjects who have a source of thrombus in the heart or the large arteries.