Heart disease risk is strongly influenced by "floating" factors (e.g., apolipoprotein B containing particles). A risk factor for Alzheimer's disease is your Ap

Heart disease risk is strongly influenced by "floating" factors (e.g., apolipoprotein B containing particles). A risk factor for Alzheimer's disease is your ApoE allele, so it's not particularly odd to me that circulating factors could influence risk. But even if not—even if the test is just picking up on incidentally released factors that are just detectable—it could be sensible. (I'm saying this completely agnostic to the claims of the article itself, just replying to your comment with general ideas.)