A study of 60 kids on Amish and Hutterite farms found a “whopping disparity” in asthma between the two groups despite their similar genetic backgrounds, lifestyles and customs.

The goal was to find an explanation for why asthma is so uncommon among Amish communities, where children run barefoot in dairy barns and farm fields, but much higher in the other group.

MIAMI — Children who grow up on traditional Amish farms in the United States are largely protected from asthma because their immune systems are bolstered by close contact with farm animals ...