I've also read some autopsy reports that showed many patients had Lyme's disease.
It is best to assume "everything is correlated with everything else", rather than jump on every correlation. On the other hand it is important to encourage people to notice correlations and coincidences, but realize not every one can be followed up on, and most of these that are noticed will be only weakly involved in any solution.
Really all we know at this point is that Alzheimer's disease is associated with the presence of more stuff that stains with antibodies raised towards Amyloid-beta aggregates than usual. It isn't even clear whether these are a cause or a symptom, nor whether these stains are near 100% specific towards beta-Amyloid (ie as derived from Amyloid precursor protein) rather than other aggregations of beta-sheets (like any prion "infection").
There was a mythical past when Hacker News was much smaller, when (early) downvotes meant something. But that's gone.
A study looking at the rates of Lyne disease and Alzheimer's by state did not find a correlation. States where Lyme disease was more prevalent tended to actually have lower rates of Alzheimer's.