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Textile industry exposures and breast cancer in women.
Checkoway-H; Thomas-DB; Yost-MG; Camp-JE; Li-W
Atlanta, GA: U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, R01-OH-008149, 2009 Dec; :1-17
Background: The etiology of female breast cancer remains poorly understood. Some evidence suggests exposure to extremely low electromagnetic fields (EMF) and light at night, from working night and/or rotating shifts, may increase risk. Suppression of melatonin by EMF and light at night is a credible underlying mechanism that is supported by experimental and epidemiologic research. The objective of this research project was to test the hypothesis that EMF and rotating shift work are risk factors for breast cancer among women textile workers in Shanghai. Methods: A total of 1707 incident breast cancer cases diagnosed between 1989 and 2000 were identified in the cohort. The comparison group compared of 3155 women randomly selected, age stratified from the whole cohort, supplemented by 1685 controls enrolled in the previous case-control studies of the cohort to make a total of 4840 woman in the comparison group. A quantitative job- exposure matrix (JEM) for the MF exposure was developed based on 1155 personal measurements of magnetic field exposure for 146 jobs that were grouped based on similar tasks defined from factory information collected in Shanghai textile industry for a previous study. Multiple exposure indices including arithmetic and geometric means, rate of change (RCM) and standardized RCM (RCMS) were calculated for each job. Detailed historical shiftwork practices were collected from 502 Shanghai textile factories. The EMF JEM and shiftwork information was linked to the work history records of women to calculate cumulative exposures. The cumulative exposures with 0, 5, 10, 15, or 20 years of lag time were categorized into quartiles to estimate hazard ratios and 95% confidence intervals with risk of breast cancer using a case-cohort design. Results: Cumulative exposures to MF and night shifts did not show any effect on risk of breast cancer in our initial analyses. All analyses were adjusted for the established risk factor for breast cancer. There was no dose-response trend observed. Conclusions: Our current results suggest that they are not associations between the workplace exposures to MF and shiftwork and the risk of breast cancer. We are further analyzing our data by controlling for other confounding factors, such as physical activity, and by categorizing EMF exposures according to the defined time windows of exposure prior to diagnosis or reference date.
Back-injuries; Worker-health; Job-analysis; Demographic-characteristics; Statistical-analysis; Quantitative-analysis; Work-environment; Worker-health; Musculoskeletal-system; Musculoskeletal-system-disorders; Ergonomics; Posture; Physical-stress; Physiological-disorders; Physiological-effects; Physiological-factors; Physiological-measurements; Physiological-response; Physiological-stress; Transportation-industry; Transportation-workers
H Checkoway, Department of Environmental and Occupational Health Sciences, School of Public Health and Community Medicine, University of Washington, Box 357234, Seattle, WA 98195-7234, USA
Final Grant Report
NTIS Accession No.
National Institute for Occupational Safety and Health
Fred Hutchinson Cancer Research Center