I think genetic factors could by themselves exhibit an exponential pattern. I have a granddaughter with type 1 diabetes, so I’ve done some thinking about it. We did not realize that I had it in my family history. In the old days people with diabetes simply died. The gene was not passed on. We’ve reached an age though where people can survive due to the miracle of science. I believe that is part of the reason the US has worse health statistics than some of these other countries. We’ve had modern medicine for a longer time and the gene pool is muddier.
I’ve been thinking about “gene pool” issues also...wondering why 90 something year old relatives are living so long, mostly in decent health, while younger ones have problems (mostly weight)....maybe the easy access to food, especially carbs (fast food, sweets, etc)...earlier in life. Just a thought. Altho the issue of autism could also be people trying to play with life - friends have an autistic grandson...his twin sister is fine...parents were in late 30s or early 40s when trying to conceive...used “help”...wondering if that doesn’t factor in also.