REVIEW OF: Zhao J et al, JAMA Network Open 2023;6(3):e236185

STUDY TYPE: Systematic review and meta-analysis

It was once thought that low to moderate drinking was protective; however, these findings have recently been called into question. The original studies compared drinkers with abstainers and reported that continuing to drink led to health benefits. It turns out that the “abstainer” comparison groups were often composed of people who stopped drinking due to medical illness rather than as a lifestyle choice. The abstainers were therefore sicker than would otherwise be expected, skewing the results in favor of participants who were drinking.

In the current systematic review and meta-analysis, researchers collated results from 107 cohort studies (~4.8 million participants) to look at the relationship between alcohol use and risk of death. Participants were broken up into four groups: abstainers, moderate drinkers (two to three standard drinks/day), high-volume drinkers (three to four standard drinks/day), and highest-volume drinkers (five or more standard drinks/day). Contrary to previous reports, no amount of alcohol consumption was associated with any improvements in mortality. High-volume drinkers had a nearly 20% increased risk of death and highest-volume drinkers had a 35% increased risk of death during study follow-up periods (ranging from approximately four to 40 years) compared to lifetime abstainers.

The authors also identified important sex differences. Moderate drinking led to increased death rates for women, but not for men, whose death rates increased only among high-volume and highest-volume drinkers. Females had a greater chance of dying than males for all levels of alcohol use.

Additionally, researchers noted that the amount of alcohol consumed in most of the included studies was self-reported. Given that self-reported alcohol consumption is consistently underreported, mortality risks for alcohol use were likely underestimated.

CARLAT TAKE

This study finds that no amount of drinking provides protection against mortality. On average, approximately two standard drinks/day increases mortality risk for females, while males see increased risk at around three or more standard drinks/day.