The largest study to date on the effects of alcohol intake among seniors has turned up mixed results: On one hand, moderate consumption significantly decreases the risk of developing dementia. However, if a person already has dementia, any alcohol consumption greatly accelerates cognitive decline.

Previous studies on the effects of alcohol on cognitive performance tended to focus primarily on the middle-aged, according to the researchers from Wake Forest University. This study involved 3,069 seniors all 75 or older. After an initial interview in which participants were asked about their alcohol intake, study subjects were categorized into four groups: abstainers (zero alcohol intake), light drinkers (one to seven drinks per week), moderate drinkers (eight to 14 drinks per week) and heavy drinkers (more than 14 drinks per week). Researchers conducted follow-up interviews every six months for six years in order to track each participant’s cognitive progression.

Those in the “moderate drinker” camp who started the study with no cognitive impairments were found to have a 37% lower risk of developing dementia than the abstaining group, according to the results. More proved not to be better, however, researchers discovered. “Heavy drinkers” and those who started the study with mild cognitive impairment experienced a far more rapid decline into dementia compared with non-drinkers. Researchers presented their findings July 13 at the Alzheimer’s Association 2009 International Conference on Alzheimer’s Disease (ICAD), in Vienna, Austria.