Relationship between dust level and byssinoiss and bronchitis in Lancashire cotton mills.

Abstract

The prevalence of bronchitis was found to be unrelated to dust level but for women was related to years of exposure. The change in symptoms of bronchitis was unrelated to dust level or to length of exposure. There was, however, an increased prevalence of bronchitis in the cotton mills when compared with the man-made fibre mills, and also over the two-year period a greater proportion of symptom-free workers developed symptoms and a lower proportion of those with symptoms lost their symptoms in the cotton mills than in the man made fibre mills. The prevalence of byssinosis was related to smoking habits, the smokers having about 1 -4 times as much byssinosis as the non- and ex-smokers after allowing for exposure. Byssino sis was associated with the dust level and years of exposure, more so for the women, and an association between the incidence of new cases over the two years and dust level was also found. After allowing for dust level, years of exposure, and smoking there were still differ ences between the occupational groups in byssinosis prevalence. Strippers and grinders had the highest prevalence followed by drawframe tenters. Speedframe tenters, card tenters, and comber tenters had similar prevalences and ring spinners the lowest. In the three-year prospective survey of cotton workers described by Molyneux and Tombleson (1970) the prevalence of byssinosis was found to be higher in coarse mills than in medium mills and to vary with occupation. Also the prevalence of bron chitis was higher in those with byssinosis. The analysis of the acute and chronic changes in lung function was given by Berry et al. (1973), and the Monday fall in forced expired volume during the