new research suggests. However, at least one expert urges caution in interpreting the findings.
Investigators found that consuming 10-14 alcoholic drinks per week had the strongest cognitive benefit. The findings “add more weight” to the growing body of research identifying beneficial cognitive effects of moderate alcohol consumption, said lead author, Ruiyuan Zhang, MD, of the department of epidemiology and biostatistics at the University of Georgia, Athens. However, Dr. Zhang emphasized that nondrinkers should not take up drinking to protect brain function, as alcohol can have negative effects.
The study was published online in JAMA Network Open.
Slower cognitive decline
The observational study was a secondary analysis of data from the Health and Retirement Study, a nationally representative U.S. survey of middle-aged and older adults. The survey, which began in 1992, is conducted every 2 years and collects health and economic data.
The current analysis used data from 1996 to 2008 and included information from individuals who participated in at least three surveys. The study included 19,887 participants, with a mean age 61.8 years. Most (60.1%) were women and white (85.2%). Mean follow-up was 9.1 years.
Researchers measured cognitive domains of mental status, word recall, and vocabulary. They also calculated a total cognition score, with higher scores indicating better cognitive abilities.
For each cognitive function measure, researchers categorized participants into a consistently low–trajectory group in which cognitive test scores from baseline through follow-up were consistently low or a consistently high–trajectory group, where cognitive test scores from baseline through follow-up were consistently high.
Based on self-reports, the investigators categorized participants as never drinkers (41.8%), former drinkers (39.5%), or current drinkers (18.7%). For current drinkers, researchers determined the number of drinking days per week and number of drinks per day. They further categorized these participants as low to moderate drinkers or heavy drinkers.
One drink was defined as a 12-ounce bottle of beer, a 5-ounce glass of wine, or a 1.5-ounce shot of spirits, said Dr. Zhang.
Women who consumed 8 or more drinks per week and men who drank 15 or more drinks per week were considered heavy drinkers. Other current drinkers were deemed low to moderate drinkers. Most current drinkers (85.2%) were low to moderate drinkers.
Other covariates included age, sex, race/ethnicity, years of education, marital status, tobacco smoking status, and body mass index.
Results showed moderate drinking was associated with relatively high cognitive test scores. After controlling for all covariates, compared with never drinkers, current low to moderate drinkers were significantly less likely to have consistently low trajectories for total cognitive score (odds ratio, 0.66; 95% confidence interval, 0.59-0.74), mental status (OR, 0.71; 95% CI, 0.63-0.81), word recall (OR, 0.74; 95% CI, 0.69-0.80), and vocabulary (OR, 0.64; 95% CI, 0.56-0.74) (all P < .001).
Former drinkers also had better cognitive outcomes for all cognitive domains. Heavy drinkers had lower odds of being in the consistently low trajectory group only for the vocabulary test.