George Astrakianakis

Colorectal cancer incidence among female textile workers in Shanghai, China: a case-cohort analysis of occupational exposures*

Previous studies have suggested increased risks of colorectal cancers among textile industry workers, potentially related to synthetic fibers. To investigate risks of colon and rectum cancers in relation to these and other textile industry exposures, we conducted a case-cohort study nested within a cohort study of female employees from the Shanghai Textile Industry Bureau (STIB). Cox proportional hazard regression modeling was used to estimate hazard ratios (HR) for colon and rectum cancers associated with duration of employment (e.g., 0, >0 to <10, 10 to <20xa0years, ≥20xa0years) in various jobs classified according to process type and exposures to specific agents. Our findings indicate that certain long term exposures may pose increased risk of colorectal cancers, especially dyes and dye intermediates with colon cancer (≥20xa0years exposure versus never, HR=3.9; 95% CI: 1.4–10.6), and maintenance occupation (HR = 2.3; 95% CI: 1.0–5.7) and metals exposure (HR = 2.0; 95% CI: 1.1–3.6) with rectum cancer. A decreased risk of rectum cancer was associated with exposure to natural fibers such as cotton (HR = 0.7; 95% CI: 0.5–0.9), and a trend of decreasing rectum cancer incidence was observed by category of cumulative quantitative cotton dust or endotoxin exposures, when exposures were lagged by 20xa0years.

Occupational risk factors for nasopharyngeal cancer among female textile workers in Shanghai, China

Aims: To investigate whether occupational exposure to dusts and chemicals in the Chinese textile industry are associated with risk of nasopharyngeal cancer. Methods: Sixty seven nasopharyngeal carcinoma (NPC) cases identified during 1989–98 and a random sample (nu200a=u200a3188) of women were included in a case cohort study nested in a cohort of 267 400 women textile workers in Shanghai, China. A complete occupational history of work in the textile industry was obtained for each woman. A job exposure matrix developed by experienced industrial hygienists was used to assess exposures to specific dusts and chemicals. Results: Risk of NPC is associated with cumulative exposure to cotton dust. The hazard ratio for women cumulatively exposed to >143.4 mg/m3 × years of cotton dust was 3.6 (95% CI 1.8 to 7.2) compared with unexposed women. Trends of increasing risk were also found with increasing duration of exposure to acids and caustics (pu200a=u200a0.05), and with years worked in dyeing processes (pu200a=u200a0.06). Women who worked at least 10 years in dyeing processes had a 3.6-fold excess risk of NPC (95% CI 1.0 to 12.1). Conclusions: Occupational exposure to cotton dust, acids, and caustics, and work in dyeing and printing jobs in the textile industry may have increased risk of NPC in this cohort.

Occupational exposures and breast cancer among women textile workers in Shanghai

Background: Breast cancer incidence rates have been increasing in China over the past 2 decades. Most studies have focused on reproductive, dietary, and genetic risk factors. Little is known about the contribution of occupational exposures. Methods: We conducted a case-cohort study within a cohort of female textile workers who had participated in a randomized trial of breast self-examination in Shanghai, China. We compared 1709 incident breast cancer cases with an age-stratified reference subcohort (n = 3155 noncases). Cox proportional hazards modeling, adapted for the case-cohort design, was used to estimate hazard ratios for breast cancer in relation to duration of employment in various job processes and duration of exposure to several agents. We also evaluated the associations of cotton dust and endotoxin with breast cancer. Results: Cumulative exposures to cotton dust and endotoxin demonstrated strong inverse gradients with breast cancer risk when exposures were lagged by 20 years (trend P-values <0.001). We did not observe consistent associations with exposures to electromagnetic fields, solvents, or other chemicals. Conclusion: Endotoxin or other components of cotton dust exposures may have reduced risks for breast cancer in this cohort, perhaps acting at early stages of carcinogenesis. Replication of these findings in other occupational settings with similar exposures will be needed to confirm or refute any hypothesis regarding protection against breast cancer.

Development of a job exposure matrix (JEM) for the textile industry in Shanghai, China

We developed a job exposure matrix (JEM) for the Shanghai textile industry constructed along three axes: industry sector, textile process, and hazardous agent. We assessed 35 different categories of dust, chemical, and physical agents for 149 textile processes within nine industry sectors: cotton, cotton/synthetic, cotton/other (nonsynthetic), wool, silk, synthetic, mineral, other mixed (e.g., wool and synthetic), and nonproduction. The JEM was constructed from two components: a priori assessment of the textile process by a team of U.S. industrial hygienists, and the prevalence of exposures reported by Chinese industrial hygienists in specific textile processes within the factory. The JEM was applied to an ongoing case-cohort study of cancer in women textile workers. The JEM assessed only dichotomous exposure (ever/never), and could be coupled with cumulative exposure by years of employment. The most common exposures in cotton mills were cotton dust and solvent exposures. Dyeing processes had the highest frequency of exposures, including solvents, acids, bases and caustics, bleaching agents, dyes, dye chemicals and intermediates, and formaldehyde. Only two processes were identified with formaldehyde exposure, beck dyeing and resin finishing. The most prevalent exposures among the subcohort, occurring in more than 60% of the women, were electromagnetic fields, lubricants, and cotton dust. More than one-third of subcohort subjects were also exposed to synthetic fiber dust, and slightly less than one-third of women were exposed to endotoxin. This JEM could be applicable for epidemiologic research in other textile industries.

Occupational risk factors for pancreatic cancer among female textile workers in Shanghai, China

Objectives To investigate whether occupational exposures to dusts and chemicals in the Shanghai textile industry are associated with risk of pancreatic cancer. Methods A case cohort study nested in a cohort of 267 400 female textile workers in Shanghai, China was conducted among 180 incident pancreatic cancer cases and an age stratified randomly selected comparison subcohort (nu200a=u200a3188). A complete occupational history of work in the textile industry was obtained for each woman, and was linked to a job exposure matrix developed for the textile industry to estimate exposures to specific dusts and chemicals. Cumulative exposures to cotton dust and endotoxin were reconstructed from historical and contemporaneous measurements. Results After adjusting for smoking status, a trend of decreasing risk of pancreatic cancer was observed for increasing cumulative exposures to cotton dust and endotoxin with a lag of 20 years. The hazard ratios for women cumulatively exposed to >143.4 mg/m3× years of cotton dust and >3530.6 EU/m3× years of endotoxin were 0.6 (95% CI 0.3 to 0.9) and 0.5 (95% CI 0.3 to 0.9), respectively, compared to unexposed women. There was little evidence that exposures to other textile dusts and chemicals were associated with risk of pancreatic cancer. Conclusions Occupational exposure to cotton dust and endotoxin in the textile industry may have reduced risks of pancreatic cancer in this cohort. These associations should be replicated by others before making a firm conclusion of their possible effects on pancreatic cancer.

Cotton Dust and Endotoxin Exposure Levels in Three Shanghai Textile Factories: A Comparison of Samplers

The results of a field survey at three Shanghai textile factories were used to compare the performance of the Chinese dust sampler (CDS) with the standard American sampler, vertical elutriator (VE). Side-by-side samples using a CDS and a VE were collected in seven specific manufacturing processes, with additional area and personal samples collected with a modified Institute of Occupational Medicine (IOM) personal inhalable sampler. Filters were analyzed for mass and endotoxin concentration. The geometric mean (GM) of the samples collected by the CDS was 0.79 mg/m3 (geometric standard deviation [GSD] 1.9) compared with a GM of 0.31 mg/m3 (GSD 1.7) for the VE measurements. The correlation coefficient for the CDS and VE samples was 0.35. The CDS, a high-volume total dust area sampler, collects 2 to 10 times more dust than the VE, a size-selective method, depending on the manufacturing process. In spinning at Factory A, the VE and CDS measured concentrations of 0.15 mg/m3 and 1.62 mg/m3, respectively. Cotton dust concentration measurements collected by the IOM sampler demonstrated that personal exposure concentrations were significantly higher (GM 1.84 mg/m3, GSD 1.6) than fixed-position area samples (GM 0.68 mg/m3, GSD 1.9). The endotoxin concentration based on the VE samples was 366 EU/m3, with the highest levels found in the specific manufacturing process drawing (1871 EU/m3) and the lowest in spinning (43.5 EU/m3). The results of the field comparison were used to convert historic CDS data into comparable exposures and to assign retrospective exposures to subjects included in a case-cohort study of lung cancer among female textile workers in Shanghai.

JOB-EXPOSURE MATRICES AND RETROSPECTIVE EXPOSURE ASSESSMENT IN THE PULP AND PAPER INDUSTRY

Abstract For the purpose of performing a case—control study, the information regarding the exposures of 30,000 pulp and paper workers was organized into 90 job-exposure matrices. Semiquantitative exposure estimates were assigned to each combination of job title and chemical or group of chemicals. The methodology used to assess exposures incorporated mill-specific and period-specific process information. An exhaustive review of processes, job titles, and chemicals coupled with the survey of each installation to evaluate equipment layout, collect hygiene data, and perform interviews of employees has yielded a comprehensive approach to estimating exposures retrospectively for the pulp and paper industry.

Occupational exposures and ovarian cancer in textile workers.

Background: Occupational risk factors for ovarian cancer have been investigated only to a limited extent. We conducted a case-cohort study to examine associations between occupational exposures and ovarian cancer in the textile industry. Methods: We compared 261 incident ovarian cancer cases diagnosed between 1989 and 1998 with an age-stratified reference subcohort (n = 3199) from a cohort of 267,400 textile workers in Shanghai, China. Occupational exposures were assessed by job-exposure matrices designed for the textile industry, and estimates of quantitative cotton dust and endotoxin. We calculated hazard ratios (HRs) and 95% confidence intervals (CIs) with Cox proportional hazards modeling adapted for the case-cohort design. Results: A decreased risk of ovarian cancer was associated with ever having worked in cotton manufacturing production (HR = 0.7; 95% CI = 0.4–1.0). An increased risk was associated with ever having worked in textile finishing (2.1; 0.9–5.0). We found an increasing risk of ovarian cancer associated with cumulative exposure to silica dust (for <10 years exposure, HR = 6.8 [CI = 0.6–76]; for ≥10 years, 5.6 [1.3–23.6]), although these results are based on only 8 exposed subcohort women (0.3%) and 4 cases (1.3%). We also detected inverse risk gradients for cumulative exposures to endotoxin when exposures were lagged by 20 years (in highest quartile, HR = 0.6 [CI = 0.4–1.1]). Conclusion: Silica dust may increase the risk of ovarian cancer, and cotton dust and endotoxin may reduce risk.

Development of a Cancer Research Study in the Shanghai Textile Industry

Abstract This article describes the development of a cancer study among Shanghai textile workers. Due to the organization of work between 1949 and the 1980s, and superior record-keeping practices, it is possible to track textile workers job tasks and workplace exposures over virtually the entirety of their working lives. The authors experiences utilized important relationships developed over more than ten years to access work exposures and cancer outcomes. Initial findings indicate a significantly increased risk for breast cancer for women employed in cotton, wool, mixed-fiber, and machine-maintenance sectors. This project is an example of the unique research opportunities to be found in China, and illustrates how these data sources may be lost due to ongoing changes in the Chinese economy.

Validation of a Mill-Specific Job-Exposure Matrix in the British Columbia Pulp and Paper Industry

Abstract Job-exposure matrices (JEMs) are being used to organize occupational exposure assessments for a nested case—control study of British Columbia pulp and paper workers. To validate the methodology used to create the JEMs, the estimates from the first mill studied were compared with personal measurements subsequently collected from that site. In total, 1678 samples were collected from workers to assess their exposure to five chemicals; these samples characterized both shift-long average and short-term high level exposures. The comparison indicated that the estimates were effective at predicting which job titles were exposed to carbon monoxide, calcium oxide, and wood dust, but less so for chlorine dioxide. Estimates were also effective at predicting which job titles were unexposed to calcium oxide, but less so for carbon monoxide, chlorine dioxide, and wood dust. The differing degrees of agreement between the estimates and measurements can be partly explained by the physical characteristics of each c...