Science has uncovered one more sex difference and this one favors the ladies. A new study finds that middle-aged men who are heavy drinkers — downing more than two and a half drinks each day — may speed their later memory loss by up to six years. Too bad for moderate middle-aged men, but what about middle-aged women? Oddly, the researchers have drawn a somewhat opposite conclusion for those who continue to raise a glass or two. “In women, there was only weak evidence that heavy drinking was associated with a faster decline in executive function, but abstinence from alcohol was associated with faster decline in the global cognitive score and executive function declines,” the authors wrote in their study published online in Neurology.

Listen carefully or you might miss the distant shouts of drunken gals not yet pushing 60.

Previous Design Flaws

Alcohol misuse and abuse is a scientifically proven cause of disease and mortality yet research also suggests alcohol may influence aging in some positive ways. Light to moderate alcohol consumption, for instance, has been found to be related to better cognitive function and lower risk of dementia, even if scientists don't understand exactly why. Generally, the impact of alcohol on cognitive aging is rarely considered definitive — it is often based on evidence from studies conducted in the elderly who have already changed their drinking patterns due to health-related concerns. In such studies, then, the heavy drinking category is either too small to be considered statistically relevant or not represented at all. Few investigations have examined the impact of drinking on cognitive aging trajectories before old age and among some of the notable exceptions, the rates of alcohol consumption were assessed only one time, so even in these cases there may have been some measurement errors.

To improve on past work, the present study’s team of researchers proposed to examine alcohol consumption and its impact on subsequent cognitive decline by assessing consumption patterns not once but three times over a 10-year period beginning in middle-age while also assessing mental function using three waves of data. The study involved 5,054 men and 2,099 women. Over the course of a decade, their drinking habits were assessed three times; a “standard drink” counted as wine, beer, or liquor only when it totaled, precisely, 0.6 fluid ounces or 14 grams of pure alcohol. This measurement is the equivalent of a 12 ounce bottle of beer, a 5-oz. glass of wine (12 percent alcohol) or a 1.5-oz. shot of distilled spirits (80-proof or 40 percent alcohol). When participants reached an average age of 56, they took their first tests of memory and executive function, the set of mental processes involved in planning, strategizing, paying attention to details, and managing time and space. These same tests were repeated twice over the next decade.

What were the results? The researchers observed no differences in memory and executive function decline among former drinkers, men who did not drink at all or those who drank less than two standard drinks each day — the light or moderate drinkers. On the other hand, those who drank more than that — the heavy drinkers — showed memory and executive function declines between one-and-a-half to six years faster than the men who drank less each day. In the words of the authors, the results of the study suggests “…heavy drinking is associated with faster decline in all areas of cognitive function in men." For women, this same story ends as if made in Hollywood.

Women Only

As mentioned previously, the researchers turned up “only weak evidence” that heavy drinking corresponded with a faster decline in executive function, while abstinence from alcohol seemed to be related to a faster decline in global cognitive score and also executive function. Almost immediately, the researchers qualified their discordant results, citing the possibility of inadequate interpretation of sex differences and a need for further clarifying research due to the fact that the total number of abstainers was small and differed greatly from the other participants in the study. When asked to explain this point, lead author Dr. Séverine Sabia, University College London, told Medical Daily in an email: “Women in the abstainers category differed in several aspects: they were more likely to have a low occupational position, not to be current smokers, practice less physical activity, eat less fruit and vegetables, and have higher prevalence of hypertension, diabetes, CVD, and depressive symptoms.” Because each of these factors may impact cognitive function, then, it is difficult for the researchers to determine whether or not abstinence, in and of itself, may have caused increased cognitive decline among the abstainers.

Ultimately, social patterns and drinking differ quite a bit when viewed through the lens of gender. “While in male heavy drinkers the proportion of individuals with high occupational position is lower than in moderate drinkers, in women the proportion of individuals with high occupational position is higher in heavy compared to moderate drinkers,” Sabia told Medical Daily. Since past studies have linked low occupational status and the risk of cognitive impairment, a woman's high occupational position may simply cancel out the risk of mental decline brought on by drinking too much.

Source: Sabia S, Elbaz A, Britton A, Bell S, Dugravot A, Shipley M, et al. Alcohol consumption and cognitive decline in early old age. Neurology. 2014.