This week's note looks at a study called "Association between daily alcohol intake and risk of all-cause mortality: A systematic review and meta-analyses" by Zhao et al. As previously discussed, systematic reviews and meta-analyses hold the highest level of evidence. They aggregate all relevant literature on a topic to draw a conclusion, which avoids cherry-picking. However, the credibility of this process relies on the quality of the original studies.
The study explored the relationship between daily alcohol consumption and all-cause mortality risk. The systematic review found 107 studies published between 1980 and 2021, involving nearly 5,000,000 participants and around 425,000 deaths. Notably, these studies were observational, establishing associations rather than causations.
The paper categorised participants by alcohol consumption, comparing different groups to lifetime non-drinkers. It highlighted the challenge of defining a non-drinker group, which includes a range of individuals, from health-conscious abstainers to former alcoholics. The study handled this challenge well.
Results revealed that occasional, low-volume, and medium-volume drinkers did not show a significantly increased risk of all-cause mortality compared to non-drinkers. However, high and highest-volume drinkers had higher risks. Notably, sex differences surfaced, with women experiencing higher mortality risks at lower consumption levels than men.
Comparing the findings to public health recommendations, the study found that potential risks occured at far higher alcohol consumption levels than those set in government guidelines.
While the discussion section acknowledged the study's strengths and limitations, it failed to delve into the sex differences observed. Potential explanations, such as physiological differences between men and women, were not explored and should have been.
In conclusion, this study contributed valuable insights into the relationship between alcohol consumption and all-cause mortality risk. It challenged public health recommendations while noting that the impact of alcohol can be quite individual.