Risk Thresholds for Alcohol Consumption: Combined Analysis of Individual-Participant Data for 599 912 Current Drinkers in 83 Prospective Studies
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, the researchers studied individual-participant data from 599,912 current alcohol users without previous cardiovascular disease.
A combined analysis was conducted of individual-participant data from three large-scale data sources in 19 high-income countries (the Emerging Risk Factors Collaboration, EPIC-CVD, and the UK Biobank). The researchers characterized dose–response associations and calculated hazard ratios (HRs) per 100 g per week of alcohol (12.5 units per week) across 83 prospective studies, adjusting at least for study or centre, age, sex, smoking, and diabetes. To be eligible for the analysis, participants had to have information recorded about their alcohol consumption amount and status (ie, non-user vs current user), plus age, sex, history of diabetes and smoking status, at least one year of follow-up after baseline, and no baseline history of cardiovascular disease. The main analyses focused on current users, whose baseline alcohol consumption was categorized into eight predefined groups according to the amount in grams consumed per week. The researchers assessed alcohol consumption in relation to all-cause mortality, total cardiovascular disease, and several cardiovascular disease subtypes. The researchers corrected HRs for estimated long-term variability in alcohol consumption using 152,640 serial alcohol assessments obtained some years apart (median interval 5.6 years [5th–95th percentile 1·04–13·5]) from 71,011 participants from 37 studies.
In the 599,912 current alcohol users included in the analysis, the study recorded 40,310 deaths and 39,018 incident cardiovascular disease events during 5.4 million person-years of follow-up. For all-cause mortality, the study recorded a positive and curvilinear association with the level of alcohol consumption, with the minimum mortality risk around or below 100 g per week. Alcohol consumption was roughly linearly associated with a higher risk of stroke (HR per 100 g per week higher consumption 1.14, 95% CI, 1·10–1·17), coronary disease excluding myocardial infarction (1.06, 1.00–1.11), 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, increased alcohol consumption was log-linearly associated with a lower risk of myocardial infarction (HR 0.94, 0.91–0.97). In comparison to those who reported drinking >0–≤100 g per week, those who reported alcohol use >100–≤200 g per week, >200–≤350 g per week, or >350 g per week had lower life expectancy at age 40 years of approximately 6 months, 1–2 years, or 4–5 years, respectively.
In current alcohol users of alcohol in high-income countries, the threshold for lowest risk of all-cause mortality was about 100 g/week. For cardiovascular disease 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 those recommended in most current guidelines.