Drinking Alcohol Associated With Smaller Brain Volume

WELLESLEY, Mass. -- The more alcohol an individual drinks, the smaller his or her total brain volume, according to a report in the October issue of Archives of Neurology, one of the JAMA/Archives journals.

Carol Ann Paul, M.S., of Wellesley College, and colleagues at Boston University School of Public Health, studied 1,839 adults (average age 60) who were part of the Framingham Offspring Study, which began in 1971 and includes children of the original Framingham Heart Study participants and their spouses. Between 1999 and 2001, participants underwent magnetic resonance imaging (MRI) and a health examination. They reported the number of alcoholic drinks they consumed per week, along with their age, sex, education, height, body mass index and Framingham Stroke Risk Profile (which calculates stroke risk based on age, sex, blood pressure and other factors).

“As part of my master of science thesis at Boston University School of Public Health, I asked the question, ‘Is there a beneficial effect of consuming small amounts of alcohol on normal decline in brain volume, as is found in the cardio-vascular system?” explained Paul. “It is known that, on average, brain volume declines at about 1.9% each decade. I wanted to know if consuming small amounts of alcohol reduced this normal decline with aging.”

Paul’s objective was to correlate alcohol consumption with brain volume. The subjects were divided into five groups: abstainers, former drinkers, low (1-7 drinks per week), moderate (8-14 drinks per week) and high (more than 14 drinks per week).

“To my surprise, after adjusting the data for variables such as age, sex, body mass index and other cardiovascular variables, there was a significant negative linear relationship between alcohol consumption and brain volume,” Paul said. “Thus it can be concluded that there is no beneficial effect of low alcohol consumption in reducing normal decline in brain volume.”

Paul noted that, while these findings are interesting, it should be remembered that this was a cross-sectional study — a snapshot in time. Longitudinal studies, which collect data over time, are needed to confirm these results.

As Paul explained, brain volume decreases with age, accompanied by an increase in white matter lesions. Lower brain volumes and larger white matter lesions also occur with the progression of dementia and problems with thinking, learning and memory. Moderate alcohol consumption has been associated with a lower risk of cardiovascular disease. Because the brain receives blood from this system, researchers have hypothesized that small amounts of alcohol may also lessen age-related declines in brain volume.

“Most participants reported low alcohol consumption, and men were more likely than women to be moderate or heavy drinkers,” the authors write. “There was a significant negative linear relationship between alcohol consumption and total cerebral brain volume.”

Although men were more likely to drink alcohol, the association between drinking and brain volume was stronger in women, they note. This could be due to biological factors, including women’s smaller size and greater susceptibility to alcohol’s effects.

“The public health effect of this study gives a clear message about the possible dangers of drinking alcohol,” the authors write. “Prospective longitudinal studies are needed to confirm these results as well as to determine whether there are any functional consequences associated with increasing alcohol consumption. This study suggests that, unlike the associations with cardiovascular disease, alcohol consumption does not have any protective effect on brain volume.”

The study can be found in (Arch Neurol. 2008; 65[10]:1363-1367 and at www.jamamedia.org.

Editor’s note: This study was supported by a contract from the National Heart, Lung, and Blood Institute’s Framingham Heart Study, National Institutes of Health; grants from the National Institute on Aging; and a grant from the National Institute of Neurological Disorders and Stroke. Please see the article for additional information, including other authors, author contributions and affiliations, financial disclosures, funding and support, etc. For more information, contact JAMA/Archives Media Relations at 312/464-JAMA (5262) or e-mail mediarelations@jama-archives.org or by contacting Wellesley College at 781-283-3321.

Since 1875, Wellesley College has been a leader in providing an excellent liberal arts education for women who will make a difference in the world. Its 500-acre campus near Boston is home to 2,300 undergraduate students from all 50 states and 68 countries.

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