Why latest alcohol study is hard to swallow

A study commissioned by the Biden administration in the US and published this week in the Journal of Studies on Alcohol and Drugs carries a headline conclusion its authors wanted written into American dietary guidelines: alcohol has no protective effect on mortality at any level, and health risks begin at one drink a day.

- Binayak Dasgupta

The Trump administration declined to feature the findings in the 2025-2030 Dietary Guidelines for Americans, advising instead that people have “less alcohol for better overall health”.

According to the analysis, men consuming 14 standard drinks a week — the upper limit the previous guidelines permitted — face a 1-in-25 lifetime risk of an alcohol-attributable death. Risk begins to register at roughly seven drinks a week for both sexes. Even levels considered “moderate” raise the risk of premature death and more than 200 diseases, including heart disease and cancer, researchers found.

But a closer look at the charts and tables shows the conclusions are not as straightforward as they appear to be.

At one drink per week, the study's central estimate — the model's single most probable value — is nota positive number representing harm. It is minus 16.30 alcohol-attributable deaths per 1,000 men. At three drinks a week, minus 10.56.

Negative numbers here imply protection: that drinking at these levels means lower risk of dying than those who do not drink at all.

The authors note that the confidence interval — the statistical range within which the true value plausibly falls — crosses zero at these doses, rendering the result uncertain. A confidence interval running from minus 47 to plus 13 deaths per thousand, as it does for men at one drink per week, is consistent with strong protection, mild harm, and everything in between — all at once.

But that is a simplistic reading of what is a statistical expression of bad study design.

Behind it is the study's architecture. It is a modelling exercise built on relative risks drawn from observational research — studies recording health outcomes in people who drink versus those who don't, without random assignment. Drinkers and non-drinkers differ in ways that resist full statistical correction: income, diet, physical activity, healthcare access.