I have read an article about DDT and how there is real concern that it could be the cause if a lot of neurological conditions. It seems even after it's use was stopped it was still in he ground as DDE and so it is under investigation as a cause if Altezimers but also other neurological conditions. Just thought you might like to investigate it. Haven't a clue how to put a link on here so you will have to Google it.
Marie x