I wish we knew for sure.
It seems to be an epidemic for people 75-90 right now. No such thing as a genetic epidemic. What was it about this generation? It was the first plastics generation, lots of plastics heated around food. Could that have been it? Hot drinks in styrofoam, in plastic mugs? TV dinners, plastic in microwaves, plastic linings in canned food? Tupperware? Nonstick pans?
Pesticides would be another potential culprit. They don’t just destroy the neurosystems of insects.
As would laundry detergents, fabric starches and treatments, dry cleaning, softeners, dryer sheets, all neurotoxic and all entering the bloodstream and brain through the skin.
It’s so hard to know.