Drug May Repair DNA at Earliest Stages of Alzheimer’s – And it’s Already Passed Safety Trials
(www.goodnewsnetwork.org)
There are genetic forms of early onset Alzheimer's that run in families. The majority of the cases are not that though. I personally believe the typical cause is a combination of environment and viruses. A similar thing has been happening with bee populations where a chemical weakens their ability to deal with parasites and viruses.
The most recent thing I read is a connection between tires and Alzheimer's.
https://www.newsweek.com/common-tire-chemical-may-raise-alzheimers-risk-study-finds-12172062