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Farm children more likely to develop hay fever

Children who lived on farms had an increased risk for hay fever, while children exposed to livestock had a decreased prevalence of atopy, according to recent study results.

Researchers assessed atopic status of 584 children (mean age, 9.57 years) in rural Saskatchewan, Canada, who completed a skin-prick test and a baseline survey. Compared with a negative control, positive reaction to any allergens, including local grasses, wheat dust, cat dander, house dust mite, Alternaria species or Cladosporium species of at least 3 mm, was used to define atopy.

Overall prevalence rates for eczema, atopy and hay fever were 27.4%, 19.4% and 8.8%, respectively, among 525 evaluable patients. Cat dander had the highest sensitization in skin-prick tests (8.6%), followed by local grasses (8.2%) and house dust mite (5.1%). Home location of farm vs. non-farm was not associated with atopic status when adjusted for potential confounders.

Children who lived on livestock farms were more protected against atopy (adjusted OR=0.38; 95% CI, 0.17-0.88), while those on farms showed an increased likelihood of hay fever (aOR=3.68; 95% CI, 1.29-10.45). Hay fever risk also increased among children who performed regular farm-related activities (aOR=2.83; 95% CI, 1.14-6.99).

“The prevalences of atopy, current allergic rhinitis and eczema were similar between farm and non-farm children, but … the difference in hay fever prevalence was greater in farm children compared with their counterparts who did not live on a farm,” the researchers concluded. “In addition, the protective effect of living on a livestock farm on atopy in this population and current residence on a farm was associated with an increase in the likelihood of hay fever in these children. Further studies are needed to look at the effects of farming and farming activities on atopy and allergic diseases.”

Disclosure: James Dosman, MD, received research funding from the Canadian Institutes of Health Research.