Children Living on Farms Have Reduced Asthma Risk

Alan Adler, MD, from the Medical College of Wisconsin, and colleagues sent 37,000 questionnaires to kindergarten through 12th grade school children in rural Wisconsin school districts. They sought to compare asthma prevalence in children who grew up on a farm to those who lived in a non-farm rural area and to determine if the amount of time the child lived on a farm was a factor. After compiling the results of 4,152 completed surveys, researchers discovered:

> Children who grew up on a farm were significantly less likely to have a history of wheezing or a diagnosis of asthma. They also reported less use of asthma medications.

> Asthma rates were higher in children who lived on a farm only after age 5 compared to those who lived on a farm before age 5 and beyond.

> During the first 2 years of life, children who grew up on a farm were less likely to report a history of chest illnesses.

Researchers also found that children who lived on a farm were significantly older, tended to have more siblings, were more frequently breast-fed, and less likely to have attended daycare. All of these factors have previously been shown to help reduce the development of allergies and asthma.

In this study, asthma was consistently reported less frequently among younger children who grew up on a farm, suggesting that exposures occurring early in life have a more significant effect in modifying asthma than those that occur later.

The JACI study was the first of its kind in the United States to compare asthma prevalence in non-urban populations. The findings coincide with similar studies completed in Europe, Australia and Canada, which suggest that early exposure to elements unique to a farm setting decrease the prevalence of asthma. However, the current study suggests that the effects of the exposure may be both time sensitive and time limited.