Cerebrovascular disorders and alcohol intake: preliminary results of a case-control study

Alcohol consumption and risk of stroke: a meta-analysis

CONTEXT

Observational studies suggest that heavy alcohol consumption may increase the risk of stroke while moderate consumption may decrease the risk.

OBJECTIVE

To examine the association between alcohol consumption and relative risk of stroke.

DATA SOURCES

Studies published in English-language journals were retrieved by searching MEDLINE (1966-April 2002) using Medical Subject Headings alcohol drinking, ethanol, cerebrovascular accident, cerebrovascular disorders, and intracranial embolism and thrombosis and the key word stroke; Dissertation Abstracts Online using the keywords stroke and alcohol; and bibliographies of retrieved articles.

STUDY SELECTION

From 122 relevant retrieved reports, 35 observational studies (cohort or case control) in which total stroke, ischemic stroke, or hemorrhagic (intracerebral or total) stroke was an end point; the relative risk or relative odds and their variance (or data to calculate them) of stroke associated with alcohol consumption were reported; alcohol consumption was quantified; and abstainers served as the reference group.

DATA EXTRACTION

Information on study design, participant characteristics, level of alcohol consumption, stroke outcome, control for potential confounding factors, and risk estimates was abstracted independently by 3 investigators using a standardized protocol.

DATA SYNTHESIS

A random-effects model and meta-regression analysis were used to pool data from individual studies. Compared with abstainers, consumption of more than 60 g of alcohol per day was associated with an increased relative risk of total stroke, 1.64 (95% confidence interval [CI], 1.39-1.93); ischemic stroke, 1.69 (95% CI, 1.34-2.15); and hemorrhagic stroke, 2.18 (95% CI, 1.48-3.20), while consumption of less than 12 g/d was associated with a reduced relative risk of total stroke, 0.83 (95%, CI, 0.75-0.91) and ischemic stroke, 0.80 (95% CI, 0.67-0.96), and consumption of 12 to 24 g/d was associated with a reduced relative risk of ischemic stroke, 0.72 (95%, CI, 0.57-0.91). The meta-regression analysis revealed a significant nonlinear relationship between alcohol consumption and total and ischemic stroke and a linear relationship between alcohol consumption and hemorrhagic stroke.

CONCLUSIONS

These results indicate that heavy alcohol consumption increases the relative risk of stroke while light or moderate alcohol consumption may be protective against total and ischemic stroke.

Alcohol consumption and stroke mortality. 20-year follow-up of 15,077 men and women

BACKGROUND AND PURPOSE

Since stroke is a principal cause of death in elderly people, we analyzed the association between alcohol and stroke mortality in a cohort of 15,077 middle-aged and older men and women.

METHODS

Data on alcohol habits were obtained from a questionnaire in 1967. The subsequent 20 years yielded 769 deaths from stroke, of which 574 were ischemic. Relative mortality risks (RR) were estimated from logistic regression analyses with lifelong alcohol abstainers as a reference group. Adjustments were made for age and smoking.

RESULTS

No association was found between alcohol intake and hemorrhagic stroke. An elevated risk of ischemic stroke was found for men who drank infrequently, that is, a few times a year or less often (RR, 2.0; 95% confidence interval [CI], 1.3 to 3.2), for those who were intoxicated now and then (RR, 1.8; 95% CI, 1.1 to 2.8), and for those who reported "binge" drinking a few times in the year or less often (RR, 1.6; 95% CI, 1.1 to 2.5). Among women only ex-drinkers had an elevated risk of dying of ischemic stroke (RR, 3.3; 95% CI, 1.5 to 7.2). The risk was reduced for women who had an estimated average consumption of 0 to 5 g pure alcohol per day (RR, 0.6; 95% CI, 0.5 to 0.8); for those who did not drink every day (RR, 0.7; 95% CI, 0.5 to 0.9); and for those who never "went on a binge" (RR, 0.6; 95% CI, 0.5 to 0.8) or became intoxicated (RR, 0.7; 95% CI, 0.5 to 0.9).

CONCLUSIONS

Drinking habits were associated only with deaths from ischemic stroke, and the risk patterns were different for men and women. In analyses, ex-drinkers should not be included with lifelong abstainers, since the former tend to run high health risk.

Stroke and alcohol intake in a hospital population. A case-control study

BACKGROUND AND PURPOSE

The aim of the study was to assess whether excessive alcohol intake is an independent risk factor for stroke.

METHODS

A case-control study was undertaken in 200 consecutive ischemic and hemorrhagic stroke patients and 372 age- and sex-matched control subjects (170 hospital-based and 202 community-based individuals). Data were collected through direct interview regarding demographics, risk factors for stroke, current daily alcohol consumption, and diagnosis of alcoholism. Blood was also taken to test the common biological markers of alcohol intake (erythrocyte mean cell volume, uric acid, aspartate aminotransferase, and gamma-glutamyl transferase).

RESULTS

After controlling for the most significant risk factors (antecedent strokes, hypertension, diabetes, smoking) and using hospital control subjects for reference, we determined the risk of stroke to be 2.2 (95% confidence interval [CI], 1.2 to 4.0) in moderate drinkers (men, < or = 60 g/d; women, < or = 40 g/d) and 2.9 (95% CI, 1.4 to 6.1) in heavy drinkers (men, > 60 g/d; women, > 40 g/d). The corresponding risk values obtained when we compared case subjects and external control subjects were 1.4 (95% CI, 0.8 to 2.7) and 3.0 (95% CI, 1.3 to 7.0). Even with some fluctuations across groups, the risk did not change significantly after subgroup analysis in men, patients with first-ever stroke, patients with ischemic stroke, and after exclusion of subjects with risk factors for stroke. Compared with hospital and external control subjects, stroke patients included a higher proportion of heavy drinkers (26.6% versus 20.6% versus 10.8%), alcoholics (14.6% versus 7.7% versus 2.5%), and cases with abnormal erythrocyte mean cell volume (63.0% versus 47.6% versus 34.2%) or gamma-glutamyl transferase (35.5% versus 32.4% versus 12.9%). Mean alcohol consumption was 42.2 g/d in the case subjects, 30.8 g/d in the hospital control subjects, and 23.2 g/d in the external control subjects.

CONCLUSIONS

The study indicates that alcohol can be considered an independent risk factor for stroke in Italy.