Large-scale research suggests that drinking alcohol in older age may lower mortality risk. However, the scientists are cautious about potential biases in their own research and say that more research is necessary.

The debate around the potential health benefits of alcohol has been ongoing. Some studies have suggested that moderate alcohol consumption extends life and protects the heart, while others have negated these benefits, arguing that the former studies are flawed and that there is no such thing as safe alcohol consumption.

For instance, some studies have suggested that light to moderate drinking helps protect women against stroke, and other studies have put this benefit down to resveratrol, the active compound in red wine.

Moderate drinking—sometimes defined as 2–7 glasses of wine per week—may also keep depression at bay, according to some research, although the same study showed that heavy drinking increased depression risk.

When it comes to the cardiovascular benefits of alcohol, the results are mixed. Some suggest that moderate consumption of wine and beer, but not spirits, protects against cardiovascular disease, while other results point to the protective benefits of drinking vodka as well as wine. However, many of the participants in these studies had a generally healthful lifestyle and adhered to a healthful Mediterranean diet, so it is hard to ascertain the precise role of alcohol in these results. Furthermore, people's drinking habits change with time, so it's hard to track the effects of alcohol. Some researchers have warned that the available data are "not sufficient to recommend drinking to anyone."

But now, the results of a new, large-scale study are in. The Health and Retirement Study (HRS) is "one of the largest and most rigorous" studies on alcohol consumption and death risk in the United States, and a new report has presented the findings of a 16-year follow-up period. The results appear in the journal Alcoholism: Clinical & Experimental Research. Katherine Keyes, PhD, an associate professor of epidemiology at Columbia University, in New York, NY, is the first and corresponding author of the study.

Studying drinking patterns over time

The new report looked at data from nearly 8,000 older adults—that is, people born between 1931 and 1941 who enrolled in the study in 1992. Since that year, researchers collected information on the participants' drinking habits and interviewed them twice a year, every year, from 1998 through 2014.

At each of these points, the researchers divided the participants into one of the following five categories: lifetime abstainers, current abstainers, heavy drinkers, moderate drinkers, and occasional drinkers.

The lifetime abstainers had consumed fewer than 12 alcoholic drinks, if any, in their lives. Current abstainers had drunk in the past, but not during the study period, while male heavy drinkers regularly had more than 3 drinks per day, and female heavy drinkers had more than 2 drinks per day.

The researchers also considered people who engaged in binge drinking—defined as 4 or more drinks in a day for women and 5 or more drinks in a day for men—to be heavy drinkers. Moderate drinkers consumed 1–2 drinks if they were women, or 1–3 drinks if they were men, on 1 or more days per week and did not engage in binge drinking.

Finally, occasional drinkers consumed alcohol less often than 1 day per week. When they did drink, they had up to 3 drinks per day, for men, and up to 2 drinks per day, for women.

Benefits to moderate, occasional drinking?

The analysis revealed that moderate and occasional drinkers had lower death rates than abstainers. Current abstainers had the highest mortality rates. However, the researchers explain, this could result from reverse causation — that is, people may have stopped drinking when their health became poor. Also, importantly, moderate and occasional female drinkers were less likely to die prematurely than lifetime abstainers.

The authors of the report warn that people should interpret the results with caution, as the HRS could contain biases and measurement errors. Also, factors that are not yet known could have influenced the results. More research is necessary.