Skip to content

Asthma Health Center

Bacteria on Farms May Protect Against Asthma

Study Shows Children Exposed to Microbes on Farms Have Lower Asthma Risk Than Other Kids
Font Size
A
A
A
By
WebMD Health News
Reviewed by Laura J. Martin, MD

Feb. 23, 2011 -- New research lends support to the idea that exposure to a wide range of microbes explains why farm kids have lower asthma rates than city kids.

School-aged children in the studies who lived on farms were about 30% to 50% less likely to have asthma than non-farm children who lived nearby.

Farm-dwelling children were also exposed to more bacteria and fungi than the other children.

The studies, which appear in the Feb. 24 edition of the New England Journal of Medicine, suggest a role for the so-called hygiene hypothesis in the development of childhood asthma.

According to the hypothesis, exposure to bacteria and fungi from environmental sources like dirt and animal hair early in life protects against asthma and allergies by helping the immune system develop normally.

It is theorized that increasingly clean environments may at least partially explain why asthma rates have doubled in developed nations in just the last three decades.

Comparing Asthma Rates

To test the theory, German researchers compared asthma rates among Bavarian children living on farms with those of children living in the same rural districts who had little direct contact with farms.

In one study, the researchers conducted DNA analysis on dust samples taken from mattresses of the two groups of children. In another, the researchers analyzed settled dust samples taken from elsewhere in the children’s bedrooms.

The analysis confirmed that kids living on farms had lower asthma rates and were exposed to a wider range of bacteria and fungi than children who did not live on farms.

There was also evidence that specific types of microbial exposures found mainly on farms played a role in the protection, study researcher Markus J. Ege, MD, of the University Children’s Hospital Munich tells WebMD.

“The farm environment is somewhat special, so there may be something about the dirt on farms that is protective,” Ege says.

While the German studies offered early clues as to what these exposures are, the next generation of research should provide much more information about the specific bacteria and/or fungi that protect against asthma, says University of Wisconsin pediatric allergy and asthma specialist James E. Gern, MD.

When Is Your Asthma Worse?

When Is Your Asthma Worse?

Take the WebMD Asthma assessment to get Personalized Action Plan

Start Now

Today on WebMD

Lung and bronchial tube graphic
5 common triggers.
group jogging in park
Should you avoid fitness activities?
 
asthma inhaler
Learn about your options.
man feeling faint
What’s the difference?
 
Madison Wisconsin Capitol
Slideshow
woman wearing cpap mask
Article
 
red wine pouring into glass
Slideshow
Woman holding inhaler
Quiz
 

Pollen counts, treatment tips, and more.

It's nothing to sneeze at.

Loading ...

Sending your email...

This feature is temporarily unavailable. Please try again later.

Thanks!

Now check your email account on your mobile phone to download your new app.

Man outdoors coughing
Article
Lung and bronchial tube graphic
Article
 
10 Worst Asthma Cities
Slideshow
runner
Article
 

WebMD Special Sections