Risk of Pancreatic Cancer in Female Textile Workers in Shanghai, China, Exposed to Metals, Solvents, Chemicals, and Endotoxin: Follow-Up to a Nested Case-Cohort Study.

OBJECTIVE: We studied associations between pancreatic cancer and occupational exposures to metals, solvents, chemicals, and endotoxin in a cohort of female textile workers in Shanghai, China. To assess the longer-term influences of these agents on pancreatic cancer we extended follow-up of this previously studied cohort. METHODS: We utilized a job exposure matrix to assess occupational exposures for 481 pancreatic cancer cases and a randomly selected sub-cohort of 3191 non-cases. We calculated hazard ratios and 95% confidence intervals using Cox proportional hazards modeling adapted for the case-cohort design. RESULTS: We observed a statistically significant trend of increasing hazard ratios associated with solvent exposure, but no associations with any of the remaining occupational exposures, including endotoxin and metals. CONCLUSIONS: Our findings of increasing risk of pancreatic cancer with solvent exposures are consistent with published literature.

Night shift work and lung cancer risk among female textile workers in Shanghai, China.

In 2007, the International Agency for Research on Cancer classified shift work that involves circadian disruption as a probable human carcinogen. Suppression of the anti-neoplastic hormone, melatonin, is a presumed mechanism of action. We conducted a case-cohort study nested within a cohort of 267,400 female textile workers in Shanghai, China. Newly diagnosed lung cancer cases (n = 1451) identified during the study period (1989-2006) were compared with an age-stratified subcohort (n = 3040). Adjusting for age, smoking, parity, and endotoxin exposure, relative risks [hazard ratios (HRs)] were estimated by Cox regression modeling to assess associations with cumulative years and nights of rotating shift work. Results did not consistently reveal any increased risk of lung cancer among rotating shift work or statistically significant trends for both cumulative years (HR 0.82, 95% CI 0.66 to 1.02; P(trend) = 0.294) and nights (HR 0.81, 95% CI 0.65 to 1.00; P(trend) = 0.415). Further analyses imposing 10- and 20-year lag times for disease latency also revealed similar results. Contrary to the initial hypothesis, rotating nighttime shift work appears to be associated with a relatively reduced lung cancer risk although the magnitude of the effect was modest and not statistically significant.

Unexpected excessive chronic obstructive pulmonary disease mortality among female silk textile workers in Shanghai, China.

OBJECTIVE: To investigate chronic obstructive pulmonary disease (COPD) mortality among textile workers. METHODS: A total of 267,400 Chinese female textile employees were monitored for COPD mortality from 1989 to 2000. Textile factories in the cohort were classified into 10 industrial sectors. Age-adjusted mortality, standardized mortality ratios (SMRs) and 95% CIs were calculated by sector. In addition, RRs (HRs) adjusted for smoking and age were calculated for exposure to cotton and silk textile work compared with the other sectors in the cohort. RESULTS: A majority of textile sectors had lower or similar COPD mortality (age-adjusted SMRs=0.58-1.15) compared with the general female population in the city of Nanjing, China. SMRs for cotton and silk workers were, respectively, 1.02 (95% CI: 0.81 to 1.28) and 2.03 (95% CI: 1.13 to 3.34). Compared with all other textile sectors in the cohort, there was greater COPD mortality among cotton workers (HR=1.40, 95% CI: 1.03 to 1.89) and silk workers (HR=2.54, 95% CI: 1.47 to 4.39). CONCLUSION: Elevated COPD mortality among cotton workers is consistent with previous reports of adverse respiratory effects of cotton dust. The higher rate of COPD deaths among silk workers was unexpected.

Biomarkers of dietary exposure are associated with lower risk of breast fibroadenomas in Chinese women.

Fibroadenomas are the most common benign breast condition among women and account for up to 50% of all breast biopsies being performed. Although considered a benign condition, fibroadenomas utilize substantial resources for management and treatment to rule out potential malignancies. Dietary factors may influence benign fibrocystic breast conditions, but little is known of their association with fibroadenomas. We examined possible associations between a broad spectrum of circulating biomarkers of dietary intake and risk of fibroadenomas. Participants were women in a breast self-examination trial in Shanghai, China who were diagnosed with fibroadenomas (n = 258) and 1035 controls. Conditional logistic regression was used to estimate adjusted odds ratios (OR) and 95% CI. Isoflavone concentrations were inversely associated with risk of fibroadenomas. Adjusted OR (95% CI) for the highest versus the lowest quartile of plasma concentration were 0.36 (0.16-0.79; P-trend < 0.001) for daidzein and 0.39 (0.19-0.84; P-trend = 0.010) for genistein. We also observed inverse associations between higher percentages of the RBC (n-3) fatty acids, eicosapentaenoic acid (EPA) ([0.38 (0.19-0.77); P-trend = 0.007] and docosapentaenoic acid (DPA) [0.32 (0.15-0.70); P-trend = 0.024], and fibroadenoma risk. Circulating concentrations of carotenoids, vitamin C, retinol, and ferritin were not associated with fibroadenoma risk. The inverse associations between plasma isoflavone concentrations and RBC EPA and DPA and fibroadenoma risk suggest that higher intakes of soy foods and fatty fish may lower the risk of fibroadenomas.

Fruit and vegetable intakes are associated with lower risk of breast fibroadenomas in Chinese women.

Fibroadenomas are common benign breast conditions among women and account for approximately 50% of breast biopsies performed. Dietary factors are known to influence benign breast conditions in the aggregate, but little is known of their association specifically with fibroadenoma. Our objective in this study was to evaluate the association between dietary and other factors and fibroadenoma risk. A case-control study, nested in a randomized trial of breast self-examination (BSE) in Chinese textile workers in Shanghai, China, was conducted between 1989 and 2000. The study sample included 327 affected women and 1070 controls. Women were administered a FFQ and a questionnaire that elicited reproductive and gynecological history and other information. Odds ratios, as estimates of relative risks, were calculated using multivariate conditional logistic regression. Significant decreasing trends in risk of fibroadenoma were observed with intake of fruits and vegetables and with number of live births, and a reduced risk was also associated with natural menopause, oral contraceptive use, and moderate exercise (walking and gardening). Increased risk of fibroadenoma was associated with heavy physical activity in one's 20s, breast cancer in a first-degree relative, and a history of prior benign breast lumps; and significant increasing trends in risk were observed with numbers of BSE per year and years of education. In conclusion, a diet rich in fruits and vegetables and the use of oral contraceptives may reduce risk of fibroadenoma.

Brain tumors and occupational exposures in a cohort of female textile workers in Shanghai, China.

OBJECTIVES: This study assessed the associations between brain tumors and specific processes and exposures among female textile workers in Shanghai, China. METHODS: A case-cohort study was conducted that was nested in a cohort of textile workers originally included in a randomized trial of breast self-examination. Incident brain tumor cases (N=114) were identified from 1989 to 1998 from a tumor and death registry operated by the Shanghai Textile Industry Bureau. A subcohort (N=3188), representing an age-stratified random sample of the entire cohort, was selected as a comparison group. Job-exposure matrices were created to assess historical exposures to specific agents, including quantitative assessments for cotton dust and endotoxin exposure. Cox proportional hazards modeling, modified according to a case-cohort design, was used to analyze associations between jobs and exposures and the risk of brain tumors. RESULTS: Employment in maintenance workshops was associated with an increased brain tumor incidence (ever-never exposed hazard ratio 2.36, 95% confidence interval 1.12-4.97), with increasing hazard ratios by duration of employment in maintenance jobs. Handling or processing wool fibers was associated with an increased risk of brain tumors, as was specific exposure to wool fibers; however, estimates did not increase with duration of employment. CONCLUSIONS: These results provide some preliminary suggestion that employment in textile industry maintenance jobs and exposure to wool products may be associated with an increased risk of brain tumors.

[Evaluation on the effect of intervention regarding breast self-examination for decreasing breast cancer mortality].

OBJECTIVE: A randomized trial of breast self-examination (BSE) Program was carried out to evaluate whether the intensive BSE could reduce the number of deaths among women from breast cancer. METHODS: This study was a randomized controlled trial (RCT). A total of 266 064 women (age of 30 to 64 years) associated with 519 textile factories in Shanghai had been randomly assigned to a BSE group (132 979 women) or a control group (133 085 women) since 1989. Initial instruction in BSE group would include demonstration of proper palpation techniques and was followed by 2 reinforcement sessions during the subsequent 4 years including video shows, BSE instruction sessions and BSE practice under medical supervision. These activities were continued for 5 years. Attendance at all events was recorded. The cohort was followed through July 2000 for development of breast diseases, and the breast cancer cases were followed through 2001 for vital status. Data analysis methods used would include Kaplan-Meier plots, log-rank test and Cox modeling. RESULTS: Among women under instruction, 864 breast cancers detected and 133 breast cancer deaths occurred while 896 breast cancers were detected and 130 deaths recorded in the control group. The tumor size (P = 0.07), TNM stage (P = 0.39) and cumulative breast cancer mortality rate (P = 0.72) were not significantly different between the 2 groups. However, more and smaller fibroadenomas were detected in the instruction group than in the control group (P< 0.01). CONCLUSION: Intensive instruction in BSE did not seem to have reduced the mortality rate of breast cancer, but more and smaller benign breast lumps could be detected.

[Randomized trial of breast self-examination in 266,064 women in Shanghai].

OBJECTIVE: A randomized trial of breast self-examination (BSE) program was carried out to evaluate whether the intensive BSE can reduce the death number of women from breast cancer. METHODS: A total of 266,064 women (age of 30 to 64 years) associated with 519 textile factories in Shanghai had been randomly assigned to a BSE instruction group (132,979 women) or a control group (133,085 women) since 1989. Initial instruction in BSE group included demonstration of proper palpation techniques. It was followed by 2 reinforcement sessions during the subsequent 4 years including video shows, BSE instruction sessions and BSE practice under medical supervision. These activities were continued for 5 years. Attendance at all events was recorded. The cohort was followed through July 2000 for development of breast diseases, and the breast cancer cases were followed up through 2001 for vital status. The data analysis methods used included Kaplan-Meier plots, Log-rank test and Cox modeling. RESULTS: Among women under instruction, 864 breast cancers were detected and 133 breast cancer deaths occurred, and 896 breast cancers were detected and 130 deaths recorded in the control group. The tumor size (P = 0.07), TNM stage (P = 0.39) and cumulative breast cancer mortality rate (P = 0.72) were not significantly different between the 2 groups. However, more and smaller fibroadenomas were detected in the instruction group than in the control group (P < 0.01). CONCLUSION: Intensive instruction in BSE can not reduce mortality rate of breast cancer, but more and smaller benign breast lumps can be detected.