…according to an article at Revue Neurologique:
The inverse relationship between moderate wine drinking and incident dementia was explained neither by known predictors of dementia nor by medical, psychological or socio-familial factors. Considering also the well documented negative associations between moderate wine consumption and cardiovascular morbidity and mortality in this age group, it seems that there is no medical rationale to advise people over 65 to quit drinking wine moderately, as this habit carries no specific risk and may even be of some benefit for their health. Advising all elderly people to drink wine regularly for prevention of dementia would be however premature at this stage.

But: alcohol is linked to higher risk of breast cancer
“Moderate wine consumption” typically more than 1 glass a day for women, no more then two for men.
Steve Parker, M.D.