When we think about alcohol’s impact on the brain, we typically think in extremes. Binge drinking can alter brain anatomy and personality in teens, alcohol abuse can leave the brain struggling to repair damage weeks after going dry.
Rarely do we consider the slow, measured effects of years of drinking on the brain, but new research is demonstrating just how much ‘every drop counts’.
Researchers from the University of Southern California examined 17,308 human brain scans from people between 45.2 and 80.7 yrs old, revealing that each additional gram of alcohol consumption per day was associated with 0.02 yrs, or 7.5 days, of increased RBA (relative brain age), which is a measure of a person’s brain age relative to their peers, based on whole-brain anatomical measurements.
Notably 1 gram of alcohol is equal to 0.035 oz, and most people who drink alcohol are going to consume 1 oz or more, which is equal to approximately 29 grams an amount that would increase RBA by 0.58 years, or 211.5 days.
“Our analyses of alcohol intake frequency and RBA indicated that subjects who drank daily or almost daily had a significantly higher RBA compared to those who drank less frequently. Our finding was consistent with previous studies, which showed that heavy alcohol consumption was detrimental to the brain,” the researchers wrote.
It could be that daily, or almost daily, drinking is part of the problem, as the study did not find a significant difference in RBA among those who drank less frequently or abstained from drinking. At least 1 study also found that light-to-moderate alcohol intake, especially wine, was associated with larger total brain volume, suggesting it is potentially beneficial for brain aging.
That said, regular and extensive alcohol consumption is a known detriment to brain health, which may cause white matter and neuronal loss and a reduction of brain volume.
This is particularly concerning, as unprecedented increases in alcohol use, high-risk drinking and alcohol use disorder aka alcoholism, have occurred in recent decades.
A study published in JAMA Psychiatry found that in the time period spanning 2001/2002 to 2012/2013, 30% more Americans engaged in high-risk drinking. The study included data from 79,402 Americans and found statistically significant increases in alcohol use across all socio-demographic groups.
The greatest increases occurred among heavy alcohol users, the number of people diagnosed with alcoholism increased by 49% during the study period and is estimated to affect 12.7%, or 1 in 8, Americans.
Overall, the number of people who reported drinking alcohol in any amount shot up from 65% to nearly 73% of Americans. About 33% of them engage in “high-risk drinking,” which was defined as five or more standard drinks for men or four or more drinks for women at least once a week. Among women this type of binge drinking increased by nearly 58% over the study period.
With heavy alcohol usage on the rise, understanding its effects on cognitive decline and neurodegenerative diseases like Alzheimer’s disease will be Key for public health.
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