BRONCHIAL HYPERRESPONSIVENESS AND EXPOSURE IN PIG FARMERS

Objective: To study the effect of exposure on bronchial responsiveness in pig farmers. Method: A group of 196 pig farmers were tested for lu ng function and bronchial responsiveness to histamine in the summer of 1992. To achieve sufficient contrast in respiratory morbidity and exp osure, 96 of the farmers were selected because they had chronic respir atory symptoms and the remaining 100 because they were free from any r espiratory 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, m ild bronchial responsiveness, defined as PC10 less than or equal to 16 mg/ml, was associated with the use of quaternary ammonium compounds a s disinfectant [prevalence odds ratio (FOR) 6.7, 95% confidence interv al (CI) 1.4-32.8], use of wood-shavings as bedding (POR 13.3, CI 1.3-1 36.7), use of automated dry feeding (POR 2.8, CI 1.0-7.8), use of pell ets as feeding material (POR 4.8, CI 1.1-21.1) and location of air exh aust via pit or roof in the confinement units (POR 2.7, CI 1.2-6.3). T he association with the use of disinfectants other than quaternary amm onium compounds was not significant (POR 2.4, CI 0.7-8.4). No associat ions between bronchial responsiveness and measured exposure to dust, e ndotoxins or ammonia were discernible. Conclusion: Protective 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 effects. Specifi cally, the use of quaternary ammonium compounds as disinfectant, the u se of wood-shavings as bedding and the use of automated dry feeding sh ould be discouraged.