Farming exposure in childhood, exposure to markers of infections and the development of atopy in rural subjects

• Published in: Clinical and experimental allergy Vol. 34; no. 8; pp. 1178 - 1183
• Main Authors: Radon, K., Windstetter, D., Eckart, J., Dressel, H., Leitritz, L., Reichert, J., Schmid, M., Praml, G., Schosser, M., Von Mutius, E., Nowak, D.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Science Ltd 01-08-2004; Blackwell; Wiley Subscription Services, Inc
• Subjects: Adult; Agriculture; Allergens; Allergic diseases; allergy; animal farming; Animal Husbandry; Animals; Animals, Domestic; asthma; atopy; Biological and medical sciences; Cattle; Child; Child, Preschool; Cross-Sectional Studies; Environmental Exposure; epidemiology; field crop; Fundamental and applied biological sciences. Psychology; Fundamental immunology; Helicobacter Infections - blood; Helicobacter Infections - immunology; Helicobacter pylori; Helicobacter pylori - immunology; Humans; Hygiene; hygiene hypothesis; Hypersensitivity - immunology; Immunoglobulin G - blood; Immunopathology; Infant; Medical sciences; Milk; Odds Ratio; Risk Factors; Rural Population; Toxoplasma - immunology; Toxoplasma gondii; Toxoplasmosis - blood; Toxoplasmosis - immunology; unpasteurized milk; Allergy; Protozoal disease; hygiene hypothesis; Spirillaceae; Biological marker; Epidemiology; Atopy; Immunology; Helicobacter pylori; field crop; Toxoplasmosis; Bacteria; Bronchus disease; Obstructive pulmonary disease; Child; Milk; Human; Lung disease; Protozoa; Immunopathology; Apicomplexa; Farming animal; Rural environment; Spirillales; Respiratory disease; Parasitosis; unpasteurized milk; animal farming; Asthma; Infection; Toxoplasma gondii; Hygiene; Farming
• ISSN: 0954-7894; 1365-2222
• DOI: 10.1111/j.1365-2222.2004.02005.x

Background
Within the context of the hygiene hypothesis, we aimed to study the potential association between farming‐related risk factors and Toxoplasma gondii (T. gondii) as well as Helicobacter pylori (H. pylori) seropositivity.
Methods
The study included questionnaire data and serum samples of 321 young adults living in a rural environment. Serum samples were analysed for specific IgE to a common panel of aeroallergens (SX1) as well as IgG against T. gondii and H. pylori.
Results
Regular contact with animal stables before the age of 3 years (odds ratio (OR) (95% confidence interval): 2.0 [1.0; 4.0]) and unpasteurized milk consumption at age 6 years (1.8 [1.0; 3.3]) were the strongest risk factors for T. gondii infection. None of the farming‐related factors were significantly associated with H. pylori infection. Current consumption of raw farm milk was not significantly associated with H. pylori infection (2.1 [0.8; 5.3]). Regular contact with animal houses before the age of 7 years was the strongest predictor for atopy (0.49 [0.26–0.96]). The reduction in risk could not be further decreased by any other factor under consideration. After adjustment for animal house contact, the OR for atopy was decreased by raw milk consumption and H. pylori infection in an additive manner.
Conclusion
Exposure to farming environments in childhood might predict T. gondii seropositivity in rural subjects. Nevertheless, the strongest predictor for atopy in rural subjects seems to be regular contact with farm animals. Whether T. gondii infection is an intermediate factor in the association between farm contact and atopy needs to be confirmed in larger studies.