Heavy Episodic Drinking, Not Average Alcohol Intake, Increases Risk of Stroke

To evaluate the effect of drinking patterns on stroke risk, researchers in Finland conducted a prospective cohort study of 15,965 men and women age 25 to 64 years who participated in a national risk factor survey. Participants had no history of stroke at baseline. The first stroke event during 10 years of follow-up served as the outcome of interest. Heavy episodic drinking was defined as consuming 6 or more drinks of the same alcoholic beverage in men or 4 or more drinks in women in 1 session. Cox proportional hazards models were adjusted for average alcohol consumption, age, sex, hypertension, smoking, diabetes, body mass index, educational status, study area, study year, and history of myocardial infarction.

• No relationship was seen between average alcohol intake and risk of total stroke (n=249) or ischemic stroke (n=179) during follow-up.

• After adjusting for average alcohol consumption, age, and sex, the hazard ratio (HR) for total strokes among persons with heavy episodic drinking was 1.85 (95% CI, 1.35–2.54) compared with persons without heavy episodic drinking. The association was diluted after adjustment for other risk factors (HR, 1.39; 95% CI, 0.99–1.35).

• The HR for ischemic stroke was 1.99 (95% CI, 1.39–2.87) among persons with heavy episodic drinking compared with persons with no heavy episodic drinking. The association remained significant after adjusting for potential confounders (HR, 1.56; 95% CI, 1.06–2.31).

• Heavy episodic drinking had no effect on the risk of hemorrhagic stroke.

Comments:

Despite having a large number of persons with heavy alcohol consumption in this study, results showed that average alcohol intake was not related to stroke risk over 10 years of follow-up. On the other hand, heavy episodic drinking was associated with a 40 to 60% higher relative risk of stroke in adjusted analyses compared with persons with no heavy episodic drinking. Only 70 participants experienced hemorrhagic stroke, which had no association with heavy episodic drinking. This analysis supports an increasingly common finding that pattern of drinking may be the most important determinant of health effects from alcohol consumption.

R. Curtis Ellison, MD

Reference:

Sundell L, Salomaa V, Vartiainen E, et al. Increased stroke risk is related to a binge drinking habit. Stroke. 2008;39(12):3179–3184.