A survey of respiratory disease in cotton operatives. II. Symptoms, dust estimations, and the effect of smoking habit.

Fox, A. J., Tombleson, J. B. L., Watt, A., and Wilkie, A. G. (1973).Brit. J. industr. Med.,30, 48-53. A survey of respiratory disease in cotton operatives. Part II. Symptoms, dust estimations, and the effect of smoking habits. In association with a survey of cotton workers dust levels were measured in 11 of the mills. Levels varied from 1·15 mg/m3 to 4·8 mg/m3 excluding fly. Analysis of the survey of workers in relation to the dust levels showed an increase in abnormal symptoms and a greater reduction in ventilatory function in those exposed to the higher dust concentrations. No such relationship was found between dust concentration and prevalence of bronchitic symptoms. Smokers showed a higher frequency of byssinotic symptoms and a greater loss of ventilatory function than non-smokers at all levels of dust exposure. The correlation between dust levels and the frequency of byssinotic symptoms and the loss of ventilatory function was increased by including a time factor. By expressing the dust exposure as mg years/m3 it can be predicted that approximately 10% of subjects exposed to 0·5 mg/m3 of dust for 40 years will have the symptoms of byssinosis.