Risks of biliary tract cancer and occupational exposures among Shanghai women textile workers: a case-cohort study.

Background: Biliary tract cancer (BTC) is a relatively rare malignancy worldwide. Little is known about potential etiologic contributions of occupational exposures.

Methods: The associations between occupational exposures to textile dusts and chemicals and BTC are investigated in a cohort of 267,400 women textile workers in Shanghai, China. A nested case-cohort analysis of 162 BTC cases diagnosed during 1989-1998 was conducted with a reference subcohort of 3,188 workers. Exposures to workplace dusts and chemicals were reconstructed by linking complete work history data with a job-exposure matrix (JEM). Hazard ratios (HR) and dose-response trends were estimated by Cox proportional hazards modeling modified for case-cohort design.

Results: An elevated risk of > or = 1-year employment in maintenance jobs (HR 2.92, 95% CI: 1.48, 5.73) with a significant trend by duration is observed. Excess risk was also found for > or = 20 years exposure to metals (HR 2.50, 95% CI: 1.09, 5.72).

Conclusions: Long-term exposure to maintenance work and metals in the textile industry may have increased BTC risk in this population.