> couple studies on Somali immigrant population in Minnesota and Sweden - where such dark skinned population naturally gets very low on vitamin D - showed such correlation as autism rates in that population is higher than back there in Somali (and that would explain the correlation of low sunlight expo.

Or autism among Somalis causes them, or their parents, to want to immigrate to Minnesota and Sweden?

No. There the vitamin D deficiency during pregnancy is correlated with autism of the child. In another study child autism was correlated with regular Swedish woman pregnancy with the 3rd trimester in winter when the deficiency is the most frequent / most serious.

It seems that autism got politicized and thus such various correlations, which may or may not be real causations, don't seem to get enough of proper scientific attention/resources. I mean, for example folic acid deficiency causes spina bifida, and it wouldn't be out-of-this-world if vitamin D (which is steroid) deficiency (or some other deficiency) would have affected prenatal development and structure of the brain which is just another body organ. Instead we spend tremendous amount of attention and energy on alleged vaccine-autism connection which hasn't been established even as mere correlation.