Reference: JAMA Netw Open. 2023 Feb 1;6(2):e2254771
Practice Point: There appears to be a U- (or more likely J-) shaped curve for alcohol and dementia risk. Everything in moderation?
EBM Pearl: This study reports data as hazard ratios (HR), which is an appropriate choice for reporting how often outcomes occur in one group compared to another over time.
Statistically speaking, there is a good chance you will indulge in some wine and chocolate tonight. But will the wine help you remember this Valentine’s Day, or is it better at helping you forget? Relationships can be complicated, including the one between alcohol and dementia. Some have described the relationship as toxic, but others might think of it as more of a secure attachment.
The body of evidence on the relationship between alcohol and dementia is conflicting. Some studies have suggested that 1-2 drinks per day might reduce dementia risk, while others have reported that abstinence is associated with the lowest risk. By all accounts heavy drinking (> 4 drinks per day) is bad, so let’s leave that out of this convo. Part of the problem is that most data come from older studies that only associated drinking status with outcomes at a certain point in time, when we all know that drinking habits evolve over a lifetime based on a variety of external and developmental factors. And also, the data are all observational. Randomized trials, which would offer the highly-touted prognostic equivalence, are not an option. Additionally, a school of thought has emerged recognizing that a current “abstainer” might have spent considerable time binging or even had an overuse problem as a younger person, in which case the damage was already done, confounding the interpretation of risk associated with “current” drinking status.
A recent study evaluated the impact of serial changes in alcohol consumption in nearly 4 million adults in Korea, and their analysis gets close, but it's no cigar. The authors separated “quitters” from “sustained nondrinkers'' during the 6-year follow up, which is a good move, except for that they still don’t distinguish the former heavy-drinkers who are now sustained nondrinkers if that change didn’t occur during the study. Using hazard ratios, the authors additionally compared risk of dementia in those who increased consumption during the study period, reduced consumption, sustained their level of drinking, and those who quit or started drinking during the study period. These analyses generated a lot of data, which when put together created a beautiful U- (or J-) shaped curve with a low threshold for benefit of alcohol consumption for reducing risk of dementia.
Common sense may dictate “everything in moderation,” but we still don’t know if there is a health benefit inherent to alcohol separate from confounders that go along with drinking, abstaining, or quitting. The authors themselves even state, “It is difficult to draw conclusions from our results without fully understanding the socioeconomic reasons underlying the changes in drinking patterns…additional studies that further support our conclusion are required before clinical application of these findings.” And to that we say, “cheers!” XOXO
For more information, see the topic Risks and Benefits of Alcohol Consumption in DynaMed.
DynaMed EBM Focus Editorial Team
This EBM Focus was written by Katharine DeGeorge, MD, MS, Deputy Editor at DynaMed and Associate Professor of Family Medicine at the University of Virginia. Edited by Alan Ehrlich, MD, Executive Editor at DynaMed and Associate Professor in Family Medicine at the University of Massachusetts Medical School; Dan Randall, MD, Deputy Editor at DynaMed; Nicole Jensen, MD, Family Physician at WholeHealth Medical; Vincent Lemaitre, PhD, Senior Medical Writer at DynaMed; and Sarah Hill, MSc, Associate Editor at DynaMed.