I wondered the same thing. As a follow-up to wazoox's comment, I looked into the mortality rates of the areas for the studies. I couldn't find the infant mort

I wondered the same thing. As a follow-up to wazoox's comment, I looked into the mortality rates of the areas for the studies. I couldn't find the infant mortality rates of Petrozavodsk, so I went to region (Republic of Karelia) instead: Infant mortality rate of Karelia in 2000 [1]: 14.4 % Of Finland: [2] 2.6 - 4.5 % So at a 3-7x higher incident rate, infant mortality does seems like a reasonable hypothesis. I wouldn't jump on the one-explanation-covers-it-all stance though. Someone else in this thread mentioned Helmenthic therapy, using parasites in a controlled manner to treat for allergies. If this treatment has seen positive results, perhaps both your point and the proposed theory explain the higher incidence of auto-immune diseases in first world countries. [1] http://www.arcticstat.org/TableViewer.aspx?S=2&ID=12668 http://www.arcticstat.org/TableViewer.aspx?S=2&ID=12668 [2] http://www.arcticstat.org/TableViewer.aspx?S=2&ID=12348 http://www.arcticstat.org/TableViewer.aspx?S=2&ID=12348