Please be advised that this information was generated on 2018-05-09 and may be subject to change.Int Arch Occiip Environ Health (1997) Abstract Objective: To study the effect of exposure on bronchial responsiveness in pig farmers. Method: A group of 196 pig farmers were tested for lung function and bronchial responsiveness to histamine in the sum mer of 1992. To achieve sufficient contrast in respira tory morbidity and exposure, 96 of the farmers were selected because they had chronic respiratory symp toms and the remaining 100 because they were free from any respiratory symptoms. Personal exposure to dust, endotoxins and ammonia was measured during 1 working day in the summer of 1991 and 1 day in the winter of 1992. Data on farm characteristics were gathered in the same period. Results: After adjusting for age and smoking behaviour, mild bronchial re sponsiveness, defined as PCi0 ^ 16 mg/ml, was asso ciated with the use of quaternary ammonium com pounds as disinfectant [prevalence odds ratio (POR) 6.7, 95% confidence interval (Cl) 1.4-32.8], use of wood-shavings as bedding (POR 13.3, Cl 1.3-136.7), use of automated dry feeding (POR 2.8, Cl 1.0-7.8), use of pellets as feeding material (POR 4.8, Cl L I-21.1) and location of air exhaust via pit or roof in the confinement units (POR 2.7, CI 1.2-6.3). The associa- tion with the use of disinfectants other than quaternary ammonium compounds was not significant (POR 2.4,. No associations between bronchial re sponsiveness and measured exposure to dust, endo toxins or ammonia were discernible. Conclusion: Pro tective measures, designed to prevent airway disease in confinement farming, should be based on information about the operational and other characteristics of farms that are related to high exposure and health ef fects. Specifically, the use of quaternary ammonium compounds as disinfectant, the use of wood-shavings as bedding and the use of automated dry feeding should be discouraged.