Dirt may explain why richest countries suffer diseases rarely seen anywhere else
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 stats downwards.