Moderate alcohol consumption and risk of stroke in US Veterans

There is inconsistent evidence on the association of moderate alcohol consumption and stroke risk in the general population and is not well studied among US Veterans. It is also unclear whether primarily drinking beer, wine, or liquor is associated with a difference in stroke risk.
185,323 participants in the Million Veteran Program who self-reported alcohol consumption on the Lifestyle Survey were included in the study. Moderate consumption was defined as 1–2 drinks/day and beverage preference of beer, wine or liquor was defined if ≥ 50% of total drinks consumed were from a single type of beverage. Strokes were identified from the participants’ electronic health record.
The mean age of the sample was 64 years. 4,339 (94% ischemic; 6% haemorrhagic) strokes over a median follow-up of 5.2 years were observed. In Cox models adjusted for age, sex, race, education, income, body mass index, smoking, exercise, diet, cholesterol, prevalent diabetes, prevalent hypertension, lipid-lowering medication, antihypertensive medication, and diabetes medication, moderate alcohol consumption (1–2 drinks/day) was associated with a 22% lower risk of total stroke compared with never drinking [Hazards ratio (HR) 95% confidence interval (CI): 0.78 (0.67, 0.92)]. When stratifying by stroke type, a similar protective association with moderate consumption and ischemic stroke [HR (95% CI): 0.76 (0.65, 0.90)], but a non-statistically significant higher risk of haemorrhagic stroke [HR (95% CI): 1.29 (0.64, 2.61)] was observed. A difference in ischemic or haemorrhagic stroke risk among those who preferred beer, liquor or wine vs. no beverage preference was not observed. When stratifying by prior number of hospital visits (≤ 15, 16–33, 34–64, ≥ 65) as a proxy for health status, the researchers observed attenuation of the protective association with greater number of visits [HR (95% CI): 0.87 (0.63, 1.19) for ≥ 65 visits vs. 0.80 (0.59, 1.08) for ≤ 15 visits].
The research found a lower risk of ischemic stroke, but not haemorrhagic stroke with moderate alcohol consumption and did not observe substantial differences in risk by beverage preference among a sample of U.S. Veterans. Healthy user bias of moderate alcohol consumption may be driving some of the observed protective association.
Source: Song, R.J., Larson, M.G., Aparicio, H.J. et al. Moderate alcohol consumption on the risk of stroke in the Million Veteran Program. BMC Public Health 23, 2485 (2023).