Associations between alcohol consumption and gray and white matter volumes Summary Excessive alcohol consumption has been associated with brain atrophy, neuronal loss, and poorer integrity of white matter fibers. However, there is conflicting evidence on whether light to moderate alcohol consumption shows similar negative associations with brain structure. To address this, we examined associations between alcohol intake and brain structure using multimodal imaging data from 36,678 generally healthy middle-aged and older adults from the UK Biobank, controlling for numerous potential confounders. Consistent with previous literature, we found negative associations between alcohol intake and brain macrostructure and microstructure. Specifically, alcohol intake is negatively associated with measures of global brain volume, regional gray matter volumes, and white matter microstructure. Here, we show that negative associations between alcohol intake and brain macro- and microstructure are already evident in people who consume an average of only one or two units of alcohol per day, and become stronger as the Alcohol intake. |
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The research, which used a data set of more than 36,000 adults, revealed that going from one to two drinks a day was linked to changes in the brain equivalent to aging two years. Excessive alcohol consumption was associated with an even higher number.
The science on excessive alcohol consumption and the brain is clear: the two do not have a healthy relationship. People who drink heavily have alterations in brain structure and size that are associated with cognitive impairments.
But according to a new study, alcohol consumption, even at levels that most would consider moderate (a few beers or glasses of wine a week), can also carry risks for the brain. An analysis of data from more than 36,000 adults, led by a team at the University of Pennsylvania, found that light to moderate alcohol consumption was associated with reductions in overall brain volume.
The link became stronger the higher the level of alcohol consumption, the researchers showed. For example, in people aged 50, as the average alcohol consumption among people increases from one unit of alcohol (about half a beer) per day to two units (a pint of beer or a glass of wine), associated changes occur in the brain. equivalent to aging for two years.
Going from two to three units of alcohol at the same age was like aging three and a half years.
The team reported their findings in the journal Nature Communications .
"The fact that we have such a large sample allows us to find subtle patterns even between drinking the equivalent of half a beer and one beer a day," says Gideon Nave, corresponding author of the study and a faculty member at Penn’s Wharton.
“These findings contrast with scientific and government guidelines on safe drinking limits,” says Kranzler, who directs the Penn Center for Addiction Studies. “For example, although the National Institute on Alcohol Abuse and Alcoholism recommends that women consume an average of no more than one drink per day, the recommended limits for men are twice that, an amount that exceeds the drinking level. associated in the study with brain decline. Volume."
Extensive research has examined the link between drinking and brain health, with ambiguous results. While there is strong evidence that heavy alcohol consumption causes changes in brain structure, including strong reductions in gray and white matter throughout the brain, other studies have suggested that moderate levels of alcohol consumption may not have an impact, or even that moderate alcohol consumption could benefit the brain. in older adults.
However, these previous investigations lacked the power of large data sets. Exploring massive amounts of data for patterns is the specialty of Nave, Daviet and their colleagues, who have conducted previous studies using the UK Biobank, a dataset containing genetic and medical information from half a million middle-aged British adults. And older.
They employed biomedical data from this resource in the current study, specifically looking at brain MRIs of more than 36,000 adults in the Biobank, which can be used to calculate the volume of white and gray matter in different regions of the brain.
“Having this data set is like having a microscope or a telescope with a more powerful lens,” says Nave. "You get better resolution and you start to see patterns and associations that you couldn’t before."
To gain an understanding of the possible connections between drinking and the brain, it was critical to control for confounding variables that could cloud the relationship. The team controlled for age, height, hand, sex, smoking, socioeconomic status, genetic ancestry and county of residence. They also corrected the brain volume data for total head size.
Volunteer participants in the Biobank had answered survey questions about their levels of alcohol consumption, from complete abstention to an average of four or more units of alcohol per day. When the researchers grouped participants by average consumption levels, a small but apparent pattern emerged: The volume of gray and white matter that might otherwise be predicted by other characteristics of the individual was reduced.
Going from zero to one unit of alcohol didn’t make a big difference in brain volume, but going from one to two or two or three units a day was associated with reductions in both gray and white matter.
Even removing heavy drinkers from the analyses, the associations remained. The lower brain volume was not located in any brain region, the scientists found.
To give a sense of the impact, the researchers compared drinking-related reductions in brain size with those that occur with aging. According to their model, each additional unit of alcohol consumed per day was reflected in a greater aging effect on the brain. While going from zero to a daily average of one unit of alcohol was associated with the equivalent of half a year of aging, the difference between zero and four drinks was more than 10 years of aging.
In future work, the authors hope to leverage the UK Biobank and other large data sets to help answer additional questions related to alcohol consumption. “This study looked at average consumption, but we’re curious about whether drinking one beer a day is better than drinking none during the week and then seven on the weekend,” Nave says. "There is some evidence that excessive drinking is worse for the brain, but we haven’t looked closely at it yet."
They would also like to be able to more definitively pinpoint causation rather than correlation, which may be possible with new longitudinal biomedical data sets that follow young people as they age.
"It is possible that we can observe these effects over time and, together with genetics, separate the causal relationships," says Nave.
And while the researchers stress that their study only looked at correlations, they say the findings may prompt drinkers to reconsider how much they drink.
“There is some evidence that the effect of drinking on the brain is exponential,” Daviet says. “So, one additional drink on a day could have more impact than any of the previous drinks that day. “That means cutting back on the last drink of the night could have a big effect in terms of brain aging.”
In other words, Nave says, “the people who can benefit the most from drinking less are the people who are already drinking more.”
