More alcohol, less brain: Association begins with an average of just one
drink a day

Date:
March 4, 2022
Source:
University of Pennsylvania
Summary:
Even light-to-moderate drinking is associated with harm to the
brain, according to a new study. Researchers analyzed data from
more than 36,000 adults that found a link between drinking and
reduced brain volume that begins at an average consumption level
of less than one alcohol unit a day -- the equivalent of about
half a beer -- and rises with each additional drink.



FULL STORY ==========================================================================
Even light-to-moderate drinking is associated with harm to the brain,
according to a new study. Researchers analyzed data from more than 36,000 adults that found a link between drinking and reduced brain volume that
begins at an average consumption level of less than one alcohol unit
a day -- the equivalent of about half a beer -- and rises with each
additional drink.


==========================================================================
The research, using a dataset of more than 36,000 adults, revealed that
going from one to two drinks a day was linked with changes in the brain equivalent to aging two years. Heavier drinking was associated with an
even greater toll. The science on heavy drinking and the brain is clear:
The two don't 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 most
would consider modest -- a few beers or glasses of wine a week -- may
also carry risks to the brain. An analysis of data from more than 36,000 adults, led by a team from the University of Pennsylvania, found that light-to-moderate alcohol consumption was associated with reductions in
overall brain volume.

The link grew stronger the greater the level of alcohol consumption,
the researchers showed. As an example, in 50-year-olds, as average
drinking among individuals increases from one alcohol unit (about half a
beer) a day to two units (a pint of beer or a glass of wine) there are associated changes in the brain equivalent to aging two years. Going
from two to three alcohol units 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 size allows us to find subtle patterns, even between drinking the equivalent of half a beer and one
beer a day," says Gideon Nave, a corresponding author on the study and
faculty member at Penn's Wharton School. He collaborated with former
postdoc and co- corresponding author Remi Daviet, now at the University
of Wisconsin-Madison, and Perelman School of Medicine colleagues Reagan Wetherill -- also a corresponding author on the study -- and Henry
Kranzler, as well as other researchers.

"These findings contrast with scientific and governmental guidelines on
safe drinking limits," says Kranzler, who directs the Penn Center for
Studies of Addiction. "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, recommended limits for men are twice
that, an amount that exceeds the consumption level associated in the
study with decreased brain volume," Ample research has examined the link between drinking and brain health, with ambiguous results. While strong evidence exists that heavy drinking causes changes in brain structure, including strong reductions in gray and white matter across the brain,
other studies have suggested that moderate levels of alcohol consumption
may not have an impact, or even that light drinking could benefit the
brain in older adults.



========================================================================== These earlier investigations, however, lacked the power of large datasets.

Probing massive quantities of data for patterns is the specialty of Nave, Daviet, and colleagues, who have conducted previous studies using the
UK Biobank, a dataset with genetic and medical information from half a
million British middle-aged and older adults. They employed biomedical
data from this resource in the current study, specifically looking at
brain MRIs from more than 36,000 adults in the Biobank, which can be
used to calculate white and gray matter volume in different regions of
the brain.

"Having this dataset is like having a microscope or a telescope with a
more powerful lens," Nave says. "You get a better resolution and start
seeing patterns and associations you couldn't before." To gain an understanding of 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, handedness, sex,
smoking status, socioeconomic status, genetic ancestry, and county
of residence. They also corrected the brain-volume data for overall
head size.

The volunteer participants in the Biobank had responded to survey
questions about their alcohol consumption levels, from complete abstention
to an average of four or more alcohol units a day. When the researchers
grouped the participants by average-consumption levels, a small but
apparent pattern emerged: The gray and white matter volume that might
otherwise be predicted by the individual's other characteristics was
reduced.

Going from zero to one alcohol units didn't make much of a difference
in brain volume, but going from one to two or two to three units a day
was associated with reductions in both gray and white matter.



========================================================================== "It's not linear," says Daviet. "It gets worse the more you drink."
Even removing the heavy drinkers from the analyses, the associations
remained.

The lower brain volume was not localized to any one brain region, the scientists found.

To give a sense of the impact, the researchers compared the reductions
in brain size linked with drinking to those that occur with aging. Based
on their modeling, each additional alcohol unit consumed per day was
reflected in a greater aging effect in the brain. While going from zero
to a daily average of one alcohol unit was associated with the equivalent
of a 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 tap the UK Biobank and other large
datasets to help answer additional questions related to alcohol use. "This study looked at average consumption, but we're curious whether drinking
one beer a day is better than drinking none during the week and then seven
on the weekend," Nave says. "There's some evidence that binge drinking
is worse for the brain, but we haven't looked closely at that yet."
They'd also like to be able to more definitively pin down causation
rather than correlation, which may be possible with new longitudinal
biomedical datasets that are following young people as they age.

"We may be able to look at these effects over time and, along with
genetics, tease apart causal relationships," Nave says.

And while the researchers underscore that their study looked only at correlations, they say the findings may prompt drinkers to reconsider
how much they imbibe.

"There is some evidence that the effect of drinking on the brain is exponential," says Daviet. "So, one additional drink in a day could have
more of an impact than any of the previous drinks that day. That means
that cutting back on that final drink of the night might 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 the most." Reagan R. Wetherillis a research assistant professor
of psychiatry in theUniversity of PennsylvaniaPerelman School of Medicine.

Henry R. Kranzleris the Benjamin Rush Professor in Psychiatry and
director of thePenn Center for Studies of Addictionat Penn's Perelman
School of Medicine.

Gideon Naveis the Carlos and Rosa de la Cruz Assistant Professor in
theWharton SchoolDepartment of Marketingand theWharton Neuroscience Initiativeat Penn.

Remi Davietis an assistant professor of marketing in theWisconsin School
of Businessat theUniversity of Wisconsin-Madison.

Daviet was first author and Wetherill, Nave, and Daviet were
co-corresponding authors on the paper.

Other coauthors were Kanchana Jagannathan, Nathaniel Spilka, and Henry R.

Kranzler of Penn's Perelman School of Medicine; Go"khan Aydogan of the University of Zurich; and Philipp D. Koellinger of the University of
Wisconsin- Madison.

The study was supported by the European Research Council (Grant 647648), National Science Foundation (Grant 1942917), National Institute on Alcohol Abuse and Alcoholism (Grant AA023894), and Mental Illness Research,
Education, and Clinical Center at the Crescenz VA Medical Center

========================================================================== Story Source: Materials provided by University_of_Pennsylvania. Note:
Content may be edited for style and length.


========================================================================== Journal Reference:
1. Remi Daviet, Go"khan Aydogan, Kanchana Jagannathan, Nathaniel
Spilka,
Philipp D. Koellinger, Henry R. Kranzler, Gideon Nave, Reagan R.

Wetherill. Associations between alcohol consumption and gray and
white matter volumes in the UK Biobank. Nature Communications,
2022; 13 (1) DOI: 10.1038/s41467-022-28735-5 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2022/03/220304090349.htm

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