When searching for my next article to review, I stumbled across a recent study out of Edinburgh which caught my eye. Unaware that the result could actually happen, I was floored when I read that previous studies have shown that in old age, cognitive abilities increase with moderate alcohol consumption. What the?!? Here I was thinking we all become drunk idiots after a few glasses of wine, but what did I know? Intrigued, I decided that I would read the full article and share the results with you.
The title of the article I will review for you today is (with full citation at the end of this post):
Alcohol Intake and Cognitive Abilities in Old Age: The Lothian Birth Cohort 1936 Study; by Janie Corley et al.
Introduction
It is known that moderate alcohol consumption in older adults is associated with reduced cardiovascular disease (which you may recall from my “Bubbly” post last week). It has also been shown that there may also be a cognitive benefit to moderate alcohol consumption as well. Specifically, studies have shown that adults consuming about one alcoholic beverage per day displayed a 20% decrease in impaired cognitive abilities and that they experienced less cognitive decline over two years (which was the length of that particular study). Other studies have shown this trend in women, but not in men, while others showed the same effect for both sexes, only with the effect being more pronounced in women than in men. Differences between studies have been attributed to factors such as methodological differences or even differences in what the definition of “moderate alcohol consumption” means.
It is not known if different types of alcoholic beverages are associated with cognitive function, though there have been some suggestions that wine is protective against cognitive decline later in life, but not beer or spirits. This suggestion is based on the antioxidant activity of flavonoids in wine; however there haven’t been consistent results among studies to know if this effect is real or not.
So how could there even be this relationship between moderate alcohol consumption and increased cognitive ability in old age? It has been speculated that this benefit exists indirectly due to a reduced risk of cardiovascular disease. Magnetic Resonance Imaging (MRI) studies have showed that there are fewer white matter abnormalities and infarcts in older adults who moderately intake alcohol compared with their nondrinking counterparts, which is indicative of a healthier brain and ultimately better cognitive abilities.
One major flaw in the research to date is that there are some potentially confounding factors that may be present which could negate the results and ultimately show no actual improvement in cognitive abilities of moderate alcohol consumers compared to their nondrinking counterparts. This article speculates that it is possible that this relationship could be attributed to prior intelligence. It has been shown that people with higher IQs tend to drink regularly (and moderately), and have been shown to have a preference for wine compared to other alcoholic beverages. Not only could IQ be a confounding factor, but socioeconomic status may also have a confounding role in this relationship.
The overall questions this study addressed were three-fold:
1) Is there a pattern of light-moderate alcohol consumption associated with better cognitive abilities in old age?
2) Do the effects on cognitive outcome vary depending on which type of alcohol is consumed?
3) Is this relationship of moderate alcohol consumption and cognitive ability attributed to confounding factors by prior cognitive abilities in youth, socioeconomic status, or both?
Methods
(Detailed methods may be read in the actual article, but I’ll give an uber-brief overview here).
The participants in this study were men and women, who were in generally good health, and of a mean age of 70 years old (total number of adults = 1,091). All resided in and around Edinburgh and Lothian, Scotland. All adults underwent cognitive testing (using a battery of neuropsychological tests), a medical/clinical assessment, and an interview. Alcohol consumption habits were determined via a questionnaire. Factors measured were: general cognitive ability, reaction time/processing speed factor, memory, mental state, verbal reasoning, and demographic/control variables.
Results
There were many results found in this study, based on the sheer number of factors that were measured.
Socioeconomic and Health Status:
· Higher alcohol consumption was associated with belonging to a professional occupation social class, have more education, and less likely to be smokers.
· Higher alcohol consumption was associated with having a higher IQ as a child, and higher IQ at age 70.
· Nondrinkers were significantly more likely to have diagnosed cardiovascular disease than moderate drinkers.
Cognitive Outcomes
· The best cognitive score for both men and women were for those drinking more than two drinks per day.
· The lowest cognitive scores were associated with nondrinkers.
Type of Alcohol and Socioeconomic/Intelligence Associations
· Women were found to drink wine almost exclusively, and men consumed a larger range of alcoholic sources.
· Men consumed more than double that of women.
· Consumption of wine (including sherry or port) and total alcohol consumption were associated with higher childhood IQ and were in a more professional social class.
Inclusion of Confounding Factors
· BEFORE including any socioeconomic or intelligence information as confounding factors, results showed a strong positive association between alcohol consumption and cognitive performance.
· AFTER controlling for socioeconomic and intelligence status, general cognitive ability and reaction time became nonsignificant, while memory remained significant (for both men and women)
· For men, wine (including sherry or port) consumption was associated with better cognitive performance; beer was associated with poorer cognitive performance, and spirits were associated with better memory performance, even when taking socioeconomic and intelligence confounding factors into consideration. These comparisons were not done for women, since they almost exclusively consumed wine and nothing else.
So, what do these results mean?
Not taking any socioeconomic or prior intelligence factors into consideration, it seems that there is a positive relationship between moderate alcohol intake and cognitive function in older adults. However, after controlling for these confounding factors, this relationship became insignificant for almost all cognitive functions tested. The only benefit that remained significant, even after controlling for socioeconomic status and intelligence was that of memory. The study reviewed for this post showed that results from previous studies not taking these confounding factors into account may be incorrect and results inaccurate.
The authors found that those with higher intelligence (IQ), and a more professional socioeconomic status are more likely to develop a preference for wine (including sherry or port), which is consistent among studies around the world (including in France and the United States).
The authors speculated that moderate alcohol consumption and a preference for wine in more intelligent adults may be the result of prior intelligence and better social circumstances throughout their life. Based on studies showing that wine drinkers, who are associated with having higher intelligence, tend to be healthier than beer or spirits drinkers, which may result in people with higher cognitive abilities to begin with engaging in lifestyles that protect them against cognitive decline later in life.
Overall Authors’ Conclusions
The authors of this study concluded that the previous idea that moderate alcohol consumption improves cognitive abilities in older adults is confounded by the fact that people have difference intelligence and socioeconomic statuses, thereby negating the results and ultimately showing no true relationship. Memory remained the only cognitive function to still be significant after the confounding factors were controlled against, suggesting that more results need be done to see if the effect is real or not.
My Final Thoughts
Though after taking socioeconomic and intelligence confounding factors into consideration, I still think the results of this study were very fascinating. Even though the positive associations between moderate alcohol consumption and improved general cognitive abilities were nullified after controlling for important factors such as prior intelligence and socioeconomic status, the fact that improvements in memory remained significantly associated with moderate alcohol consumption in a positive manner is very important and worth further research.
It’s fascinating: one would think the more you drink, the more you forget, but apparently, this is not the case! I suppose this relationship may be the inverse for excessive alcohol consumption. So to sum up in one sentence: moderate alcohol consumption (particularly wine or spirits) may improve memory function in older adults, though further research needs to be done to confirm/refute this theory.
Full Citation:
Corley, J., Jia, X., Brett, C.E., Gow, A.J., Starr, J.M., Kyle, J.A.M., and McNeill, G. 2011. Alcohol Intake and Cognitive Abilities in Old Age: The Lothian Birth Cohort 1936 Study. Neuropsychology 25 (2). 166-175.
What do you all think about this study? Share your thoughts below in the comments section. I’d love to hear from you!
I am not a health professional, nor do I pretend to be. Please consult your doctor before altering your alcohol consumption habits. Do not consume alcohol if you are under the age of 21. Do not drink and drive. Enjoy responsibly!
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