This is the largest, longest U.S. study to look at the effects of regular alcohol intake on dementia in seniors, both with and without memory problems.
For the study, researchers at Wake Forest University School of Medicine examined and interviewed 3,069 individuals, 75 years or older and most without any memory or thinking problems, about their drinking habits.
Participants were asked about beer, wine, and liquor. The researchers then categorized the individuals as abstainers (non-drinkers), light drinkers (one to seven drinks per week), moderate drinkers (eight to 14 drinks per week), or heavy drinkers (more than 14 drinks per week). All types of alcohol were included.
The study subjects were then examined and interviewed every six months for six years to determine changes in their memory or thinking abilities and to monitor who developed dementia.
The researchers found that individuals, who had no cognitive impairment at the start of the study and drank eight to 14 alcoholic beverages per week, or one to two per day, experienced an average 37 percent reduction in risk of developing dementia compared to individuals who did not drink at all and were classified as abstainers.
For older adults who started the study with mild cognitive impairment, however, consumption of alcohol, at any amount, was associated with faster rates of cognitive decline.
n addition, those who were classified in the heavy drinker category, consuming more than 14 drinks per week, were almost twice as likely to develop dementia during the study compared to non-drinkers with mild cognitive impairment.
"We were excited to see that even in older adults, moderate alcohol intake decreases the risk of dementia. It is important to note, however, that our study found a significantly higher risk of dementia for heavy drinkers who started the study with mild cognitive impairment," said Kaycee Sink, M.D., M.A.S (Masters of Advanced Studies in clinical research), a geriatrician and senior author of the study.
The study has been presented at the Alzheimer's Association 2009 International Conference on Alzheimer's Disease (ICAD), in Vienna on July 13.