Berry and colleagues examined the data from one of these studies and reported the 3-year changes in pulmonary function in both cotton textile workers and synthetic fiber control workers. Cotton workers had an excess annual loss in lung function (54 ml) versus control workers (32 ml). However, the annual decline in lung function was not related to across-shift change in lung function or to symptoms of byssinosis or bronchitis, and information on symptom variability over time was not reported. Valic and Zuskin studied a small group of workers exposed to coarse cotton dust over 10 years and found that the prevalence of both byssinosis and nonspecific respiratory symptoms increased with the duration of exposure to cotton dust. Beck et al studied textile workers prospectively in a community-based study in South Carolina and reported a chronic effect of cotton dust exposure on lung function that was independent of cigarette use. Zuskin et al recently reported a follow-up study of a small group (n=66) of textile workers exposed to high levels of dust and examined over 10 years. Canadian neighbor pharmacy read more This group represented about 57 percent of the original cohort and were found to have an increasing prevalence of respiratory symptoms as well as progressive lung function decline.
Based on the common understanding of respiratory symptoms, we would have expected acute symptoms, such as chest tightness at work, to be variable, while chronic symptoms (eg, chronic bronchitis), whether due to cigarette smoking, cotton dust exposure, or a combination of these, would be expected to persist and result in consistent reporting. To the contrary, however, our data demonstrated considerable variation over time in the reporting of “chronic” respiratory symptoms among textile workers. Although not anticipated, this finding is consistent with at least one other published report and that of the US Six-Cities study over a 12-year period of follow-up (unpublished data, Dockery et al). In our study, however, workers who consistently reported symptoms at both surveys tended to lose lung function at a higher rate than workers who never or inconsistently reported them. This suggests that, despite considerable distractions in the collection of symptom data over time, there is useful information regarding markers of developing pulmonary impairment.