Cross-shift Airway Responses and Long-Term Decline in FEV1 in Cotton Textile Workers

摘要

Rationale: Acute airway response, measured as cross-shift change in FEV1, to cotton dust may lead to subsequent chronic loss of lung function in exposed workers.Objectives: To explore the association between the magnitude and frequency of cross-shift change and chronic loss of FEV1.Methods: Four hundred eight cotton workers and 417 silk workers from Shanghai textile mills were observed prospectively for 20 years, with cross-shift measurements at baseline and follow-up surveys at approximate 5-year intervals. To account for repeated measures of 5-year change, generalized estimating equations were used to estimate the relationship between the magnitude of cross-shift change in FEV1 (ΔFEV1) and subsequent 5-year annualized change. Linear regression models were used to examine the association between the number of drops in cross-shift FEV1 (ΔFEV1 < 0) and annualized change over the entire study period.Measurements and Main Results: Exposure to cotton dust was associated with a 10 ml/year decrement in 5-year annualized FEV1 decline. In addition, every 10 ml in ΔFEV1 drop was associated with an additional 1.5 ml/year loss in annualized FEV1 decline. The association between the frequency of drops and annualized decline was stronger for cotton workers than for silk workers over the entire study period.Conclusions: Cotton workers had larger and more frequent drops, as well as excessive chronic declines in FEV1, than did silk workers. The magnitude and frequency of cross-shift drops were associated with chronic loss in FEV1 over the entire 20-year period examined.