The researchers also found that low or moderate consumption did not reduce the risk of stroke, which contradicts the findings of some previous studies. The study is published in the rapid access edition of Stroke: The Journal of the American Heart Association.
"Previous studies conducted with older adults found an association between heavy drinking, brain atrophy and an increased risk for stroke. We studied a younger, middle-aged population and found that low amounts of alcohol consumption are also associated with decreases in brain size," said Jingzhong Ding, PhD, lead author of the study and a research associate in the Department of Epidemiology at the School of Public Health. "Our findings do not support the hypothesis that low or moderate alcohol intake offers any protection against cerebral abnormalities or the risk of stroke in middle-aged adults."
For the study, Dr. Ding and his colleagues used magnetic resonance imaging (MRI) to measure the brains of 1,909 men and women, age 55 and older. All were randomly selected from the Atherosclerosis Risk in Communities Study. The MRI was used to access brain size and to detect infarcts and white matter lesions, which are changes in the brain associated with an increased risk for stroke. The researchers categorized the participant's drinking habits either as never drank, former drinker, occasional drinker (less than one drink per week), low drinker (one to six drinks per week) or moderate drinker (seven to 14 drinks per week).
The researchers found as alcohol consumption increased, the MRI detected increases in the ventricular and sulcal areas of the brain, which are spaces that do not contain brain tissue and an indication of brain atrophy. However, they found no consistent association between alcohol intake and the presence of infarctions or white matter lesions.
Former drinkers and moderate drinkers were more likely to have infarctions compared to those who never drank without adjusting for other factors. After adjusting for factors such as smoking habits, body mass and income, the researchers found no reduction or protection in infarction associated with former drinkers or moderate drinkers. In addition, they did not find an association between alcohol intake and white matter lesions.
"Because MRI measures in the brain were only conducted once during follow up, a causal relationship between alcohol intake and brain atrophy is difficult to establish," explained Dr. Ding. "The strength of the study lies in the large population-based sample and the consistency of the findings by gender and race."
