PULMONARY-FUNCTION AMONG COTTON TEXTILE WORKERS - A STUDY OF VARIABILITY IN SYMPTOM REPORTING, ACROSS-SHIFT DROP IN FEV(1), AND LONGITUDINAL CHANGE

Longitudinal variability in respiratory responses, including symptom r eporting and across-shift change in ventilatory function, were examine d in relation to long-term loss of ventilatory function in a group of 447 cotton textile workers in Shanghai, China. The study used a standa rdized respiratory questionnaire and standardized spirometric testing before and after a work shift on the first day of the workweek. Predic tion equations for FEV(1) were generated from a group of silk textile workers from the same city. Environmental samples included both vertic al elutriated cotton dust and endotoxin levels. There was considerable variability in symptom reporting between the baseline and g-year foll ow-up survey for all symptoms. However, subjects who consistently repo rted symptoms had a significantly accelerated 5-year loss in FEV(1) co mpared with those who never reported symptoms. Subjects with symptoms of chest tightness or dyspnea at one survey lost FEV(1) at a rate inte rmediate between the never or both groups. Moreover, subjects with an cross-shift change in FEV(1) of more than 5 percent at both surveys ha d the greatest loss in FEV(1) over 5 years (-267 ml) when compared wit h one-time responders (-224 ml), and nonresponders (-180 ml), though t he differences were not significant. Workers with chest tightness and chronic bronchitis in both surveys were overrepresented in the high du st and endotoxin areas. Our results indicate that even with substantia l survey-to-survey variability in responses, there is important inform ation contained in both questionnaires and across-shift spirometry. Am ong cotton workers, consistent responders to either symptom questionna ire or across-shift FEV(1) decrements of greater than or equal to 5 pe rcent appear to be at increased risk for lung function impairment.