Risk thresholds for alcohol consumption: combined analysis of individual-participant data for 599 912 current drinkers in 83 prospective studies

14 Feb 2018

Background Low-risk limits recommended for alcohol consumption vary substantially across different national guidelines. To define thresholds associated with lowest risk for all-cause mortality and cardiovascular disease (CVD), we studied individual-participant data on 599,912 current drinkers without prior CVD. Methods We characterised dose-response associations and calculated hazard ratios (HRs) per 100 grams/week of alcohol (12.5 units/week) across 83 prospective studies in 19 countries, adjusting at least for study/centre, age, sex, smoking, and diabetes. We recorded 40,317 deaths and 39,018 incident CVD events during 5.4 million person-years of follow-up. We corrected HRs for long-term variability in alcohol consumption using 152,640 serial alcohol assessments obtained some years apart (median interval: 5.6 years). Findings For all-cause mortality, there was a positive and curvilinear association, with minimum risk around or below 100 grams/week. Alcohol consumption was approximately linearly associated with higher risk of: stroke (HR, 95% CI: 1.14, 1.10-1.17); coronary disease excluding myocardial infarction (1.06, 1.00-1.17); heart failure (1.09, 1.03-1.15); fatal hypertensive disease (1.24, 1.15-1.33); and fatal aortic aneurysm (1.15, 1.03-1.28). By contrast, alcohol consumption was log-linearly associated with lower risk of myocardial infarction (0.94, 0.91-0.97). Compared with current low-risk limits in US guidelines (196 grams/week for men), consumption of less than 100 grams/week could increase male life expectancy by about 1-2 years. Interpretation Among current drinkers, the threshold for lowest risk of all-cause mortality was about 100 grams/week. For CVD subtypes other than myocardial infarction, there were no clear risk thresholds below which lower alcohol consumption stopped being associated with lower disease risk. These data support limits for alcohol consumption that are lower than in current guidelines.