Studies in the elderly have linked excessive alcohol consumption to the cognitive decline and dementia.
A review paper by Kim JW et al published in Psychiatry Investig
2012;9:8-16 on the association between alcohol consumption and cognition in the elderly provides an excellent summary of the potential ways in which alcohol may affect cognitive function and the risk of dementia, both adversely and favorably as alcohol may have both a neuro toxic and neuro protective effect, depending on the dose and drinking pattern.
Longitudinal and brain imaging studies in the elderly show that excessive alcohol consumption may increase the risk of cognitive dysfunction and dementia, but regular low to moderate alcohol intake may protect against cognitive decline and dementia and provide cardiovascular benefits.
Studies published from 1971 to 2011 related to alcohol and cognition in the elderly were reviewed using a PubMed search. At present, there are no proven agents to prevent cognitive decline or dementia, although a number of prospective epidemiologic studies have shown a lower risk of such conditions among light to moderate drinkers in comparison with non-drinkers. Other studies have found that beneficial effects are seen only among certain sub-groups of subjects. A recent meta-analysis by Peters et al of subjects over the age of 65 in longitudinal studies concluded that light-to-moderate alcohol consumption, in comparison with abstinence, was associated with approximately 35-45% lower risk of cognitive decline or dementia.
This paper provides a summary of what is known about the mechanisms by which alcohol consumption, especially heavy drinking, can be neurotoxic, and how light-to-moderate drinking may help protect against cognitive decline and dementia. The authors state that their intent is to determine if there is an "optimal pattern of drinking" that may protect the elderly against such conditions.
At present, the mechanisms by which the moderate intake of wine and other alcoholic beverages reduces the risk of cardiovascular diseases are much better defined than they are for cognition. Forum members agree with the authors that further research is needed to evaluate a potential role that alcohol may play in reducing the risk of dementia.
Forum members also agree that, at present, the specific mechanisms of such putative protection are not well defined, and it would be premature to recommend light-to-moderate drinking for reducing the risk of dementia. On the other hand, current biomedical data supports the concept that regular, moderate intake of ethanol is not simply less dangerous for cognitive function, but is positively protective. This is the same conclusion reached by epidemiologic studies."