Austrian children living on a farm have less hay fever, asthma and allergic sensitization

TLDR

Studies show that children in rural areas have lower rates of hay fever and asthma compared to urban peers, possibly due to immunotolerance or TH1/TH2 modulation from microbial exposure on farms. The study aimed to determine whether farm living protects against allergic sensitization and allergic diseases in children. Researchers conducted a cross‑sectional survey of 2,283 8‑10‑year‑old Austrian children, collecting questionnaire data and performing skin‑prick tests on 1,137 participants for seven local allergens. Farm children exhibited significantly lower prevalence of hay fever (3.1 % vs 10.3 %), asthma (1.1 % vs 3.9 %) and allergen sensitization (18.8 % vs 32.7 %), and regular contact with livestock further reduced sensitization risk.

Abstract

Background and objectives In some studies, the prevalence of hay fever and asthma has been found to be lower in children from rural areas than in children from an urban environment. We hypothesized that living on a farm might be protective against development of allergic sensitization and allergic diseases. Methods In a cross‐sectional survey, parents of 2283 children aged 8–10 years from a mostly rural area in Austria answered a standardized questionnaire on allergic diseases and environmental factors. 1137 children performed a skin prick test to seven local allergens. Results The prevalence of hay fever (3.1 vs 10.3%, P = 0.0002), asthma (1.1 vs 3.9%, P = 0.017) and a positive skin prick reactivity to at least one of the common local allergens (18.8 vs 32.7%, P = 0.001) was significantly lower in children living on a farm than in children from a non‐farming environment. In a multivariate logistic regression model, adjusting for genetic background, parent education, living and housing conditions and dietary factors did not change the odds ratio for the association of farming and allergic sensitization. Only after including ‘regular contact with livestock and poultry’ into the model did the odds ratio change significantly (cOR 0.48 95% CI 0.30–0.75 to aOR 0.75 95% CI 0.37–1.52) indicating an association between regular contact with farm animals and reduced risk of atopic sensitization. Conclusion Possible explanations for the lower prevalence of hay fever, asthma and allergic sensitization in children living on a farm might be the development of immunotolerance or the stimulation of TH1 cells and suppression of TH 2 cells by increased exposure of farm children to microbial antigens in the stables or farmhouses.