Inverse association of farm milk consumption with asthma and allergy in rural and suburban populations across Europe

Abstract

Background Dietary interventions as a means for atopy prevention attract great interest. Some studies in rural environments claimed an inverse association between consumption of farm‐produced dairy products and the prevalence of allergic diseases, but current evidence is controversial. Objective To investigate whether consumption of farm‐produced products is associated with a lower prevalence of asthma and allergy when compared with shop‐purchased products. Methods Cross sectional multi‐centre study (PARSIFAL) including 14 893 children aged 5–13 years from five European countries (2823 from farm families and 4606 attending Steiner Schools as well as 5440 farm reference and 2024 Steiner reference children). A detailed questionnaire including a dietary component was completed and allergen‐specific IgE was measured in serum. Results Farm milk consumption ever in life showed a statistically significant inverse association with asthma: covariate adjusted odds ratio (aOR) 0.74 [95% confidence interval (CI) 0.61–0.88], rhinoconjunctivitis: aOR 0.56 (0.43–0.73) and sensitization to pollen and the food mix fx5 (cut‐off level of 3.5 kU/L): aOR 0.67 (0.47–0.96) and aOR 0.42 (0.19–0.92), respectively, and sensitization to horse dander: aOR 0.50 (95% CI 0.28–0.87). The associations were observed in all four subpopulations and independent of farm‐related co‐exposures. Other farm‐produced products were not independently related to any allergy‐related health outcome. Conclusion Our results indicate that consumption of farm milk may offer protection against asthma and allergy. A deepened understanding of the relevant protective components of farm milk and a better insight into the biological mechanisms underlying this association are warranted as a basis for the development of a safe product for prevention.