Association Between Daily Alcohol Intake and Risk of All-Cause Mortality. A Systematic Review and Meta-analyses
Original investigation
This updated meta-analysis did not find significantly reduced risk of all-cause mortality associated with low-volume alcohol consumption after adjusting for potential confounding effects of influential study characteristics.
Future longitudinal studies in this field should attempt to minimize lifetime selection biases by not including former and occasional alcohol users in the reference group, and by using younger cohorts (ie, age distributions that are more representative of alcohol users in the general population) at baseline.
Key Points
Question
What is the association between mean daily alcohol intake and all-cause mortality?
Findings
This systematic review and meta-analysis of 107 cohort studies involving more than 4.8 million participants found no significant reductions in risk of all-cause mortality for alcohol users who consumed less than 25 g of ethanol per day (about 2 Canadian standard alcoholic drinks compared with lifetime non-alcohol users) after adjustment for key study characteristics such as median age and sex of study cohorts. There was a significantly increased risk of all-cause mortality among female alcohol users who drank 25 or more grams of alcohol per day and among male alcohol users who drank 45 or more grams of alcohol per day.
Meaning
Low-volume alcohol consumption was not associated with protection against death from all causes.
Abstract
Importance
A previous meta-analysis of the association between alcohol use and all-cause mortality found no statistically significant reductions in mortality risk at low levels of consumption compared with lifetime non-alcohol drinkers.
However, the risk estimates may have been affected by the number and quality of studies then available, especially those for women and younger cohorts.
Objective
To investigate the association between alcohol use and all-cause mortality, and how sources of bias may change results.
Data Sources
A systematic search of PubMed and Web of Science was performed to identify studies published between January 1980 and July 2021.
Study Selection
Cohort studies were identified by systematic review to facilitate comparisons of studies with and without some degree of controls for biases affecting distinctions between alcohol abstainers and alcohol users. The review identified 107 studies of alcohol use and all-cause mortality published from 1980 to July 2021.
Data Extraction and Synthesis
Mixed linear regression models were used to model relative risks, first pooled for all studies and then stratified by cohort median age (<56 vs ≥56 years) and sex (male vs female). Data were analyzed from September 2021 to August 2022.
Main Outcomes and Measures
Relative risk estimates for the association between mean daily alcohol intake and all-cause mortality.
Results
There were 724 risk estimates of all-cause mortality due to alcohol intake from the 107 cohort studies (4 838 825 participants and 425 564 deaths available) for the analysis.
In models adjusting for potential confounding effects of sampling variation, former alcohol users bias, and other prespecified study-level quality criteria, the meta-analysis of all 107 included studies found no significantly reduced risk of all-cause mortality among occasional (>0 to <1.3 g of ethanol per day) or low-volume alcohol users (1.3-24.0 g per day) compared with lifetime non-alcohol users.
In the fully adjusted model, there was a nonsignificantly increased risk of all-cause mortality among alcohol users who drank 25 to 44 g per day and significantly increased risk for alcohol users who drank 45 to 64 and 65 or more grams per day.
There were significantly larger risks of mortality among female alcohol users compared with female lifetime non-alcohol users.
Conclusions and Relevance
In this updated systematic review and meta-analysis, daily low or moderate alcohol intake was not significantly associated with all-cause mortality risk, while increased risk was evident at higher consumption levels, starting at lower levels for women than men.
