*Alcohol abuse is largest risk factor
> Most reviews point to a possible beneficial effect of light-to-moderate drinking on cognitive health... By contrast, heavy drinking seems detrimentally related to dementia risk, whatever the dementia type.
> Most reviews point to a possible beneficial effect of light-to-moderate drinking on cognitive health... By contrast, heavy drinking seems detrimentally related to dementia risk, whatever the dementia type.
Citation needed
Latest meta-analyses say that after controlling for reasons behind non-drinkers (‘former alcoholics’) the effect disappears.
Good starting point is https://www.ncbi.nlm.nih.gov/m/pubmed/26997174/