A review of 23 longitudinal studies of older adults (65+) has found that small amounts of alcohol were associated with lower incidence rates of overall dementia and Alzheimer dementia, but not of vascular dementia or age-related cognitive decline. A three-year German study involving 3,327 adults aged 75+ extends the evidence to the older-old.
The study found alcohol consumption was significantly associated with 3 other factors that helped protect against dementia: better education, not living alone, and absence of depression. Nevertheless, the lower risk remained after accounting for these factors.
The ‘magic’ amount of alcohol was between 20-29g, roughly 2-3 drinks a day. As in other studies, a U-shaped effect was found, with higher risk found among both those who consumed less than this amount of alcohol, and those who consumed more.
 . Current alcohol consumption and its relationship to incident dementia: results from a 3-year follow-up study among primary care attenders aged 75 years and older. Age and Ageing [Internet]. 2011 . Available from: http://ageing.oxfordjournals.org/content/early/2011/02/23/ageing.afr007.abstract