Meta-analysis: Alcohol consumption does not lower all-cause mortality risk

Key takeaways:

• Low or moderate daily alcohol intake did not offer protection against all-cause mortality.
• High levels of intake were linked to higher risks.
• The dangers were worse for women than men.

Drinking a low or moderate amount of alcohol every day was not significantly linked to all-cause mortality, but high levels of intake were, especially for women, according to results of a meta-analysis published in JAMA Network Open.

Jinhui Zhao, PhD, a scientist at the Canadian Institute for Substance Use Research at the University of Victoria, and colleagues wrote that “the proposition that low-dose alcohol use protects against all-cause mortality in general populations continues to be controversial.”

“Observational studies tend to show that people classified as ‘moderate drinkers’ have longer life expectancy and are less likely to die from heart disease than those classified as abstainers,” they wrote. “Systematic reviews and meta-analyses of this literature confirm J-shaped risk curves (protective associations at low doses with increasing risk at higher doses).”

Zhao and colleagues added that a previous meta-analysis found alcohol use was not linked to statistically significant reductions in mortality risk, but those risk estimates could have been impacted by the quality and number of studies that were available, particularly among women and younger people.

So, the researchers conducted a systematic review and meta-analysis to better understand the connections between alcohol intake and all-cause mortality and how sources of bias can affect results.

They identified cohort studies with a systematic review to facilitate comparisons of studies with and without some bias controls that could affect distinctions between abstainers and drinkers. Their final analysis included 107 studies published between January 1980 and July 2021.

Zhao and colleagues identified 724 risk estimates of all-cause mortality due to alcohol intake from the 107 cohort studies, which included 4,838,825 participants and 425,564 deaths for the analysis.

In models that adjusted for potential confounding effects of sampling variation, former drinker bias and other pre-specified criteria, the researchers found no significantly reduced risk of all-cause mortality among low-volume drinkers (1.3-24 g of ethanol per day; RR = 0.93; P = .07) and occasional drinkers (>0 to <1.3 g of ethanol per day; RR = 0.96; 95% CI, 0.86-1.06).

However, in the fully adjusted model, there was a non-significant increased risk for all-cause mortality in those who drank 25 g to 44 g per day (RR = 1.05; P = .28) and significantly increased risk for those who drank 45 g to 64 g and 65 g or more g per day (RR = 1.19 and 1.35; P < .001).

Notably, the dangers of higher consumption began at lower levels for women than men, according to the researchers. Compared with female lifetime non-drinkers, female drinkers had significantly larger risks of mortality (RR = 1.22; P = .03).

“A larger risk of all-cause mortality for women than men was observed when drinking 25 or more grams per day, including a significant increase in risk for medium-level consumption for women that was not observed for men,” Zhao and colleagues wrote. However, mortality risk for mean consumption up to 25 g per day were very similar for both sexes.”