Fewer allergic respiratory disorders among farmers' children in a closed birth cohort from Sweden

The aim of this study was to investigate the prevalence of respiratory allergy, eczema and atopic sensitization in a closed birth cohort of Swedish schoolchildren, 7-8 yrs of age (n = 707), of farmers and nonfarmers on the island of Gotland, in the Baltic Sea, All children were born and raised on the island. The survey comprised a questionnaire on atopic diseases and lifestyle factors. Atopic sensitization was assessed by the skin-prick test (SPT) with 15 standardized allergens. The risk ratio (RR) for ever having asthma and/or allergic rhinoconjunctivitis was significantly lower among children of farmers compared to children of nonfarmers (RR = 0.38, confidence interval (CI) 95%, 0.19-0.77), SPTs (test rate 92%) showed that 32% of the children had at least one positive test. Although the number of positive SPTs did not differ between the groups, there was a reduced risk among children of,topic sensitization farmers for having both respiratory symptoms and sensitization to any allergen (RR = 0.28, CI 95%, 0.09 - 0.88). The present indicate that living in a farming population seems to protect against hay fryer development of respiratory allergic disorders but not against allergic sensitization.