I am not qualified to read the data well, but one of my immediate thoughts was "Well if you live long enough you're basically guaranteed dementia, perhaps abstaining from alcohol helps you get that old?"
Not true; I'm sure there is a relationship between age and prevalence of dementia, but it's far from a guarantee.
I've known too many centennials of surprisingly sound mind, and they eventually start having falls and the body can't heal sufficiently to fully recover.
Once the dementia sets in, though, that's another story. The aging process seems to advance quicker when dementia is present.
https://www.nature.com/articles/s41598-022-11427-x
(Unfortunately it increases the risk of some cancers, too.)