Health Secrets of the Amish

Fascinating: Comparison of Amish (farmers, low rates of allergies, asthma) with Hutterites (farmers, high rates of allergies, asthma). Considerable common genetic stock.

Preliminary conclusion: Husbandry practices. Amish stock is kept near the home, all Amish do at least some work with animals, and all are exposed to animals. Microbial load estimated at six times higher than Hutterites, who keep their animals far from home and only whose adult males tend and are regularly exposed to animals.

New England Journal of Medicine article (free download) http://www.nejm.org/doi/full/10.1056/NEJMoa1508749

Is exposure to the allergens only helpful when it occurs during childhood?