People who drank wine weekly or monthly were more than two times less likely to develop dementia in the study.
"These results don't mean that people should start drinking wine or drink more wine than they usually do," said study author Thomas Truelsen, MD, PhD, of the Institute of Preventive Medicine at Kommunehospitalet in Copenhagen, Denmark.
"But the results are exciting because they could mean that substances in wine reduce the occurrence of dementia," he said. "If that's the case, we could potentially develop treatments or prevention methods based on these substances."
The researchers hypothesize that flavonoids, natural compounds that have an antioxidant effect, may be the substance responsible for the beneficial effect. Red wine is high in flavonoids. Other studies have suggested that flavonoids may account for a lower occurrence of stroke and other cerebrovascular diseases among wine drinkers.
For the study, the researchers identified the drinking patterns for wine, beer and liquor of 1,709 people in Copenhagen in the 1970s and then assessed them for dementia in the 1990s, when they were age 65 or older. Over the two decades, 83 of the participants developed dementia. Their alcohol intake was compared to that of those who did not develop dementia.
The study also found that occasional beer drinking was associated with an increased risk of developing dementia. Those who drank beer monthly were more than two times more likely to develop dementia than those who never or hardly ever drank beer.
Those who drank wine every day were no more or less likely to develop dementia than those who drank it more or less often.
One limitation of the study is that eating habits were not assessed, states an accompanying editorial by neurologist John Brust, MD, of Harlem Hospital Center in New York, NY.
"Research suggests that wine drinkers may have better dietary habits than beer and liquor drinkers," Brust said. "There is also evidence that dietary vitamin E may reduce the risk of developing Alzheimer's. These factors were not accounted for in this study.
"Nonetheless, this is a provocative report providing evidence that there is indeed something specifically beneficial about wine."
The study was supported by grants from Danish National Board of Health, Danish Ministry of Health, the University of Copenhagen, "Else og Mogens Wedell-Wedellsborgs Fond," the Danish Health Insurance Foundation, the Danish Insurance Association, the Medical Scientific Foundation for the Copenhagen Region, the Faroe Islands and Greenland, Chief Physician, DMSc Torben Geill's Fund, and the Centenary Fund of the Copenhagen Municipality Hospital.
The American Academy of Neurology, an association of more than 18,000 neurologists and neuroscience professionals, is dedicated to improving patient care through education and research. For more information about the American Academy of Neurology, visit its web site at www.aan.com.