Drinking heavy amounts of alcohol over a long period of time may decrease brain volume, according to research presented at the American Academy of Neurology’s 59th Annual Meeting in Boston, May 3rd 2007.
Study author Carol Ann Paul, MS, of Wellesley College in Wellesley, MA and her colleagues examined the long term effects of alcohol consumption by using MRI scans acquired from 1999 to 2002 of 1,839 non-demented participants in the Framingham Offspring Study, to analyse brain volume.
They divided participants into five categories based on self-reported alcohol consumption frequency: abstainers, former drinkers, low drinkers (one to seven drinks per week), moderate drinkers (eight to 14 drinks per week), and heavy drinkers (more than 14 drinks per week).
The authors made pair-wise comparisons of mean total cranial volumes across the various groups, and created multivariate linear regression models to see whether there was an association between brain size and alcohol consumption. They controlled their analyses for age, gender, body mass index, height, educational level attained, and Framingham Stroke Risk Profile. They also looked at the longitudinal history of alcohol consumption from 1987 to 2001 to see whether there were associations with total cranial volume.
“I found that ...there was no beneficial effect of alcohol on brain volume,” Paul said. “In addition, I found that there was a slightly more strong effect in women than in men, and on the preliminary longitudinal studies, it seemed that people who had been heavy drinkers throughout the 12-year period we looked at, had significantly decreased brain volume in comparison to the others.”
Specifically, the authors found a reduction in brain volume of 0.25% for every additional category of alcohol consumption. In contrast, the average age-related decline in brain volume is 0.19% per year, she noted.
Gender modified the alcohol-brain volume relationship significantly (P=0.0029), with men having a slightly lower downward slope than women, meaning that brain volume decreased more in women than men across categories of alcohol consumption.
The authors also detected a significant negative correlation between alcohol consumption and brain volume among women in their 70’s (P= 0.013), and in the longitudinal analysis, they found that heavy drinking was negatively associated with brain volume (P=0.005, -0.026).
“Each drink category is approximately equivalent to one-to-two years of aging,” Paul said, adding that the effect was linear across the categories from low to high.
She suggested that although alcohol consumption in moderation has beneficial effects on the cardiovascular system, it may be found to be associated with deleterious effects on neurons and neural circuitry.