The relationship of respiratory symptoms and lung function loss in cotton textile workers

We explored the relationship between a number of respiratory symptoms or symptom complexes (e.g., cough, recent wheeze, byssinosis) and lung function in white cotton textile workers (CTW) and control subjects 45 yr of age or older. The CTW were studied in 1973 and in 1979 in Columbia, South Carolina, and the control subjects were studied in 1972 and in 1978 in Lebanon, Connecticut. The CTW had a high prevalence of byssinosis (18%) and other symptoms. For each symptom or symptom complex, among persons with the symptom, CTW had lower lung function on the average than did control subjects. Also, among persons without the particular symptom, CTW had lower lung function than did control subjects. This pattern also occurred for persons without any respiratory symptoms (i.e., asymptomatic). Moreover, persons (CTW or control subjects separately) reporting the presence of a particular symptom had, in general, lower lung function than did those without the symptom. Among nonsmokers, all these same patterns usually held, but differences were often not statistically significant because of the small numbers of persons with symptoms. We conclude that on a group basis, respiratory function is more impaired in CTW than in control subjects with respiratory symptoms, that respiratory function is more impaired in persons (CTW or control subjects) with symptoms than in those without, and that even asymptomatic CTW have significantly greater lung function impairment than do control subjects.