Chronic respiratory symptoms of poultry farmers and model-based estimates of long-term dust exposure

Objectives. The airborne contaminant exposure levels experienced by poultry farmers have raised concerns about the possible health hazards associated with them. Thus, a longitudinal project was instituted in France to monitor these exposures in poultry workers and to evaluate the long-term effect on health. Method. Sixty-three workers in two different poultry housing systems were included (33 from floor-based systems and 30 from cage-based systems). Personal dust concentrations (over 2 days) and activity patterns (over 14 days) were collected and then modeled to obtain average long-term estimates. Health data were collected by questionnaire. Results. The mean daily time spent in the cage system was more than 2 hours longer than in the floor system. Two main common tasks accounted for ~70% of this time. Dust concentrations were higher in the floor system than in the cage system. The concentrations for the 14 days of known activity patterns estimated using the statistical model agreed well with the measured values. Several chronic respiratory symptoms were significantly associated with the high levels of long-term exposure estimated by the model. The highest risk was for chronic bronchitis symptoms (>4-fold higher for exposures of 0.1 mg/m 3 of respirable dust). Conclusion. The presented modeling strategy can be used to estimate the long-term average personal exposure to respirable dust, and to study the association between dust exposure and chronic respiratory symptoms. This population of workers will be followed-up in subsequent examinations (3 years later) to determine whether the predictive model is valid, and whether long-term dust exposure is related to the incidence of respiratory symptoms and changes in pulmonary functions.