Longitudinal Changes in Pulmonary Function and Respiratory Symptoms in Cotton Textile Workers

Abstract

To evaluate the chronic effects of exposure to cotton dust, a 15-yr follow-up study in cotton textile workers was performed in Shanghai, China from 1981 to 1996. Testing occurred four times during the 15-yr period. The achieved follow-up rates were 76-88% of the original 447 cotton textile workers, and 70-85% of the original 472 silk textile workers (as a control group). Identical questionnaires, equipment, and methods were used throughout the study. The prevalence of byssinosis increased over time in cotton workers, with 15.3% at the last survey versus 7.6% at the baseline, whereas no byssinosis was found in silk workers. More workers in the cotton group consistently reported symptoms than in the silk group, although symptom reporting varied considerably from survey to survey. Cotton workers had small, but significantly greater, adjusted annual declines in FEV(1) and FVC than did the silk workers. Years worked in cotton mills, high level of exposure to endotoxin, and across-shift drops in FEV(1) were found to be significant determinants for longitudinal change in FEV(1), after controlling for appropriate confounders. Furthermore, there were statistically significant associations between excessive loss of FEV(1) and byssinosis, chest tightness at work, and chronic bronchitis in cotton workers. Workers who consistently (three or four of the surveys) reported byssinosis or chest tightness at work had a significantly greater 15-yr loss of FEV(1). We conclude that long-term exposure to cotton dust is associated with chronic or permanent obstructive impairments. Consistent reporting of respiratory symptoms, including byssinosis and chest tightness at work, is of value to predict the magnitude and severity of chronic impairments in textile workers.

A 20-year follow-up study on chronic respiratory effects of exposure to cotton dust

“…The result was consistent with that observed in male grain workers, in which annual losses in FEV1 were 28.7 mL for nonsmokers, and 41.7 mL for current smokers [13]. Overall, the data provide further supportive evidence for the chronic effects of exposure to cotton dust, which has been suggested by the current authors' previous observations [8,9] and by other cohort studies [4,5].…”

“…Throughout the study, identical samples, sampler-location handling techniques and measurements were used. The sampling methods and calculated cumulative personal exposure to dust and endotoxin at each time period have been described previously [9].…”

“…In the current study, the symptoms of interest included byssinosis, chest tightness, chronic bronchitis, chronic cough and dyspnoea, as defined previously [9]. Byssinosis was not ascertained at the last survey, since all of the workers had left the industry by that time.…”

“…Spirograms were performed at each survey by a trained technician with consistent methods, according to American Thoracic Society criteria [9]. An 8-L water-sealed filled spirometer (W.E.…”

“…The results of a cohort study that followed a group of Chinese textile workers exposed chronically to cotton dust have been reported previously [8,9]. One of the features of the cohort was that .50% of the workers were nonsmoking females, which allowed an assessment of the effects of cotton-dust exposure without confounding by smoking.…”