Farm-raised kids are less prone to asthma. Who gets the credit? Germs, researchers say.

Children raised on farms don’t suffer from asthma as much as their city- and suburb-dwelling counterparts, according to a paper published online Wednesday in the New England Journal of Medicine. But it’s not necessarily because of the fresh air, full sun and hard work, researchers say -- it’s because of the germs.

Scientists had known that many of the things associated with farm life -- unpasteurized milk, exposure to animals such as cows and pigs, and hay -- helped kids grow up with stronger constitutions, perhaps because they were being exposed to harmless, even beneficial, bacteria along the way. To test this hypothesis, the researchers analyzed samples of house dust to look at the microbes within.

They showed that children on farms, where the bacteria population is far more diverse, were 30% to 50% less likely to have asthma than children who didn’t live on farms. The wider the range of microbes in the houses, the less likely it was that the children would suffer from asthma.

Also, those who lived on farms were much less likely to have atopy -- an umbrella term for certain types of hyperallergic sensitivity, including hay fever, asthma and eczema. But the drop in atopy was linked to a certain group of bacteria, not to the range of microbes.

Among the possible explanations for the findings: that the beneficial bacteria that live around farms could be staving off some of the harmful bacteria that exacerbate asthma.

Does this mean urban humans are too clean for their own good? Post your thoughts below.

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