[Study on the health of cotton mill workers]

A group of 110 workers in a cotton mill was investigated by questionnaire, skin testing, and the measurement of airway responsiveness through forced expiratory volume for one second(FEV1) by spirometry. The workers were examined before starting work, 10 weeks and one year after exposure. Decreases in FEV1 over shifts were small at 10 weeks and one year, and were slightly higher among people with positive skin reactions to cotton dust extracts. Airway responsiveness, defined as the average decrease in FEV1 after 1.25 mg methacholin, was increased at 10 weeks. It remained about the same after one year, except in the workers with positive skin test. Subjective symptoms of chest tightness and cough with phlegm increased progressively at 10 weeks and one year. Nasal irritation remained unchanged and dry cough decreased in one year. The results suggest that the airway inflammation caused by cotton dust increases with the exposure time and that the changes are more notable in workers with reactivity to cotton dust extract.