The Amish have other health issues that don't get a whole lot of attention - problems arising from inbreeding. Plus, look at their lifestyle - no TV, no video games, no processed foods, no electricity, and lots of outside exercise.
It's impossible to point out one difference between the Amish and the English (that's us) and say that is the cause of various problems. It's much more complicated than that
I just cited the Amish study because they have way less autistic children than they should have according to all the studies done on autism. Also, I did say there are a few autistic children there, but those were adopted children who had vaccinations. BTW, I think that autism is caused by toxins in the environment, not by heredity. It is not a coincidence that autism first appeared at the same time that the mercury preservative was put into the vaccinations.
My point, though, is that there should be NO toleration of mercury in any vaccinations for people. Period. I also wonder where the vaccinations are made and who checks them to make sure of what precisely is in them.