BACKGROUND: Recent studies have shown that in several countries atopic sensitization to common allergens (common atopy) and atopic symptoms are markedly less prevalent in children living on a farm, compared with non-farm children living in the same rural areas. Living conditions on farms may, however, vary largely between different countries. It is also not yet known whether the "protective" effect of a farm environment can also be found in adults. MATERIALS AND METHODS: Common atopy and respiratory health were assessed by skin prick tests (SPT), questionnaire and measurement of bronchial hyper-responsiveness (BHR) in the Sund Stald (SUS) study, a cohort study on respiratory health in Danish farming students and conscripts from the same rural areas as controls. Results of SPT were confirmed by IgE serology in all SPT+ subjects and a subset of SPT- subjects. Prevalences of common atopy, respiratory symptoms and bronchial hyper- responsiveness were compared for farmers and controls, and for those who had or had not lived on a farm in early childhood. RESULTS: In multiple logistic regression analyses adjusting for ever smoking and a familial history of allergy, both being a farmer (ORs 0.62-0.75) and having had a farm childhood (ORs 0.55-0.75) appeared to contribute independently to a lower risk of sensitization to common allergens as assessed by SPT and IgE serology. A farm childhood was also inversely associated with high total IgE (OR 0.68), presence of respiratory symptoms (ORs 0.69-0.79) and BHR (OR 0.61) in these analyses. Direction and strength of the association between being a farmer and respiratory symptoms or BHR varied widely (ORs 0.69-1.28). CONCLUSION: The "anti-atopy" protective effect of a farm childhood could be confirmed in Danish farming students: prevalences of positive SPT, specific and total IgE, allergic symptoms and BHR were lower in those being born or raised on a farm. Past exposure to the farm environment in early childhood may therefore also contribute to a lower risk of atopic sensitization and disease at a later age.
BACKGROUND: Recent studies have shown that in several countries atopic sensitization to common allergens (common atopy) and atopic symptoms are markedly less prevalent in children living on a farm, compared with non-farm children living in the same rural areas. Living conditions on farms may, however, vary largely between different countries. It is also not yet known whether the "protective" effect of a farm environment can also be found in adults. MATERIALS AND METHODS: Common atopy and respiratory health were assessed by skin prick tests (SPT), questionnaire and measurement of bronchial hyper-responsiveness (BHR) in the Sund Stald (SUS) study, a cohort study on respiratory health in Danish farming students and conscripts from the same rural areas as controls. Results of SPT were confirmed by IgE serology in all SPT+ subjects and a subset of SPT- subjects. Prevalences of common atopy, respiratory symptoms and bronchial hyper- responsiveness were compared for farmers and controls, and for those who had or had not lived on a farm in early childhood. RESULTS: In multiple logistic regression analyses adjusting for ever smoking and a familial history of allergy, both being a farmer (ORs 0.62-0.75) and having had a farm childhood (ORs 0.55-0.75) appeared to contribute independently to a lower risk of sensitization to common allergens as assessed by SPT and IgE serology. A farm childhood was also inversely associated with high total IgE (OR 0.68), presence of respiratory symptoms (ORs 0.69-0.79) and BHR (OR 0.61) in these analyses. Direction and strength of the association between being a farmer and respiratory symptoms or BHR varied widely (ORs 0.69-1.28). CONCLUSION: The "anti-atopy" protective effect of a farm childhood could be confirmed in Danish farming students: prevalences of positive SPT, specific and total IgE, allergic symptoms and BHR were lower in those being born or raised on a farm. Past exposure to the farm environment in early childhood may therefore also contribute to a lower risk of atopic sensitization and disease at a later age.
Authors: Ioannis Basinas; Torben Sigsgaard; Hans Kromhout; Dick Heederik; Inge M Wouters; Vivi Schlünssen Journal: J Expo Sci Environ Epidemiol Date: 2013-11-27 Impact factor: 5.563
Authors: Lidwien A M Smit; Moniek Zuurbier; Gert Doekes; Inge M Wouters; Dick Heederik; Jeroen Douwes Journal: Occup Environ Med Date: 2006-10-03 Impact factor: 4.402
Authors: John S House; Annah B Wyss; Jane A Hoppin; Marie Richards; Stuart Long; David M Umbach; Paul K Henneberger; Laura E Beane Freeman; Dale P Sandler; Elizabeth Long O'Connell; Christie Barker-Cummings; Stephanie J London Journal: J Allergy Clin Immunol Date: 2016-11-12 Impact factor: 10.793