That forum post advises "new drugs aimed at preventing Alzheimer’s should probably target surrogate markers rather than trying to fix the end-stage clinical problems".

Here's One Weird Trick for targeting Alzheimer's, to try at home. Grey hair is correlated with Alzheimer's. Hair dye is a treatment that targets that particular biomarker, with remarkable efficacy. How about we all use hair dye, in the hope it prevents Alzheimer's! Way cheaper than $56k/year too.