I'm surprised that the article didn't touch on differences in childhood mortality rates. The theory proposed has always made a lot of sense to me. However, I would expect any reporting on the topic to consider the extent to which the allergy-sufferers amongst us (such as myself) made it through childhood because of better early childhood medical care, thus skewing the later-in-life allergies and autoimmune disease st…
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…
Agreed that both probably have an impact. I imagine that there's some sort of scientific method out there to tease out the impacts of the two factors, probably via an aggregation of a number of such studies.