ABSTRACT
Recent studies suggest that pesticides may contribute to respiratory symptoms and morbidity. We evaluated the association between personal pesticide application and a common respiratory symptom, wheeze, among 20 468 licensed pesticide applicators, primarily farmers, in Iowa and North Carolina who participated in the Agricultural Health Study. Over 19% of applicators reported wheeze in the past year. Sixteen of the 40 pesticides evaluated were associated with an increased odds of wheeze. Parathion, an organophosphate, had the strongest association. We observed increased wheeze associated with other pesticides suggested from the literature including paraquat and malathion. Studying the respiratory health effects of pesticides among farmers is challenging due to the nature of the pesticide products, patterns of pesticide exposure, and other contributing exposures on farms. Our analyses had sufficient power to control for other farm activities such as animal production. Self-selection into specific farming activities may result in underestimates of risk if sensitive individuals remove themselves from exposure. Future work needs to be longitudinal, collect exposure information simultaneously with symptoms, and examine other aspects of respiratory function.