Pulmonary function study of retired cotton textile workers and the relationship to cigarette smoking

A group of 173 retired cotton textile workers from one cotton mill in Shanghai was surveyed. A modified British Medical Research Council (BMRC) questionnaire was administered, and lung function tests were performed using an LR-80 flow-volume machine made in China. All workers had worked in the preparatory and spinning departments for more than 25 years. A group of 373 healthy age-matched individuals with similar social, economic, and educational backgrounds but with no history of dust or any toxic agent exposure was selected as the control group. Pulmonary function parameters from the forced expiratory effort were recorded. Prediction equations were derived from 157 controls who had never smoked and had no history of respiratory or cardiovascular disorders. The ratios of observed to predicted values in the male and female cotton textile workers and controls were examined using two-way analysis of variance and Student's t test. There was no significant difference between the cotton textile workers and the controls in lung function parameters, whereas cigarette smoking had a distinct impact on all the parameters except forced vital capacity. The effects of cotton dust exposure and cigarette smoking appeared to be additive. It is suggested that the effect of cigarette smoking on the respiratory tract may be located mainly in the small airways.