The relationship between the pattern of alcohol intake and the risk of stroke is unclear, in particular the increased risk observed in abstainers and the possible protective effect of light to moderate drinking. For that reason, we examined in a large prospective study the role of alcohol consumption in the risk of a first major cerebrovascular event (stroke).
We prospectively studied 7735 middle-aged men drawn from general practices in 24 British towns. With exclusion of those who had recall of physician diagnosis of ischemic heart disease or stroke, data were available for 7273 men all followed for 13.5 years, with 216 major stroke events (fatal and nonfatal).
Compared with occasional drinkers, nondrinkers (lifelong abstainers plus ex-drinkers) had an increased risk of stroke even after adjustment for age, lifestyle factors, and preexisting cardiovascular disease (relative risk [RR] = 1.6; 95% CI, 1.0 to 2.7). All regular weekend drinkers (1 to 2, 3 to 6, and > 6 drinks/d) and daily 1 to 2 and 3 to 6 drinkers showed no significant difference in adjusted risk of stroke compared with occasional drinkers. Heavy drinkers (daily > 6 drinks) showed significantly increased risk evident within the first 8 years of follow-up only (RR = 1.9; 95% CI, 1.0 to 3.5); however, this finding was attenuated after additional adjustment for systolic blood pressure (RR = 1.5; 95% CI, 0.8 to 2.7). Information obtained 5 years after screening was used to separate lifelong abstainers and ex-drinkers. On subsequent 8.5 years of follow-up, both groups showed similar increased risk (RR = 1.5) compared with occasional drinkers, but the risk in ex-drinkers was reduced after adjustment for lifestyle factors and cardiovascular disease status (RR = 1.2). Lifelong abstainers, however, showed an increase in risk after adjustment of 1.8 (95% CI, 0.7 to 4.6).
Heavy drinking is associated with an increased risk of total stroke that is largely mediated through blood pressure. The apparent increased risk seen in lifelong abstainers but not in ex-drinkers or occasional drinkers is unexplained but is unlikely to be attributed to abstinence from alcohol. There is no convincing evidence that light or moderate drinking is beneficial for stroke risk compared with occasional drinking.