PT Journal AU Melbostad, E Wijnand, E Magnus, P TI Determinants of asthma in a farming population SO Scandinavian Journal of Work, Environment & Health PD 8VL PY 1998 BP 262 EP 269 IS 4 DI 10.5271/sjweh.319 WP https://www.sjweh.fi/show_abstract.php?abstract_id=319 DE airway obstruction; asthma; cross-sectional study; family history; farmer; genetic factor; occupational exposure; smoking SN 0355-3140 AB '

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OBJECTIVES ': 'This study examined the determinants of asthma in a population of farmers, including as a crude indicator of genetic predisposition "history of asthma in next-of-kin" (family history), and exposure factors such as animal production and smoking.'

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METHODS ': 'In a cross-sectional study of 8482 farmers or farmers' spouses in Norway a questionnaire with information on asthma among the subjects and their next-of-kin, production type and farming activities, exposures outside farming, and smoking was applied. Spirometry was performed.'

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RESULTS ': 'The lifetime prevalence of self-reported asthma in the population was 6.3%. Significant risk factors for current asthma were asthma among next-of-kin, asthma as child or adolescent, animal production, and age. In a comparison with subjects with no family history of asthma and no animal production the adjusted odds ratio for current asthma in never smokers was 1.9 [95% confidence interval (95% CI) 0.4-8.9] for subjects with family history only, 2.2 (95% CI 1.1-4.2) for subjects with animal production only, and 6.3 (95% CI 3.1-13.1) for subjects with both factors. A combination of animal production, smoking, and a positive family history gave an odds ratio of 8.1 (95% CI 4.0-16.2) for current asthma.'

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CONCLUSION ': 'The study can be interpreted as support for the hypothesis of an interaction between genetic factors and exposure factors in the causation of asthma. Since familial associations may be exposure-related, the necessity of considering indicators of both inheritance and exposure in epidemiologic studies of asthma is emphasized.

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