An Epidemiological Study for Breast Cancer among Female Electronics Workers and Reproductive Outcomes in Offspring
|Keywords:||乳癌;癌症;心臟缺陷;孩童;電子業;白血病;先天性畸形;下一代;有機溶劑;標準化發生率比;三氯乙烯;Breast cancer;Cancer;Cardiac defects;Children;Electronics;Leukemia;Malformation;Offspring;Organic solvents;Standardized incidence ratio;Trichloroethylene||Issue Date:||2008||Abstract:||
Backgroundn 1994, a hazardous waste site, polluted by the dumping of solvents from a former electronics factory, was discovered in Taoyuan, Taiwan. This subsequently emerged as a serious case of contamination through chlorinated hydrocarbons with suspected occupational cancer. There is limited evidence on the hypothesis that maternal occupational exposure near conception increases the risk of cancer in offspring, and the association between paternal occupational exposure during preconception and infant mortality from congenital malformation. he objectives of this study were to determine if there was any increased risk of breast cancer among female workers in a 23-year follow-up period, to investigate whether women employed in this electronics factory increases childhood cancer among first live born singletons, and to determine if such an association existed among male workers employed in this electronics factory.ethods total of 63,982 female workers were retrospectively recruited from the database of the Bureau of Labor Insurance (BLI) covering the period 1973-1997; the data were then linked with data, up to 2001, from the National Cancer Registry at the Taiwanese Department of Health, from which standardized incidence ratios (SIRs) for different types of cancer were calculated as compared to the general population. e linked the databases of birth registration and labor insurance, and national cancer registry, which identified 40,647 female workers ever employed in this factory who gave 40,647 first live born singletons, and 47 of them developed cancers during 1979-2001. Mothers employed in this factory during their periconceptional periods (three months before and after conception) were considered as exposed and compared with those not employed during the same periods. Poisson regression model was constructed to adjust for potential confounding by maternal age, education, sex, and year of birth. e also inked the databases of birth registration, labor insurance, and national death registry, identified 7,545 male workers ever employed in this factory with 14,453 live born children and 83 deaths in the first year. Fathers employed in this factory during their preconceptional periods (three months prior to the conception) were considered as exposed compared with those not employed during the same periods. After excluding 442 children with potential maternal exposure from the same workplace, Poisson regression models were constructed to adjust for potential confounding by child’s gender, parity, multiple births, year of birth, parental age at delivery and educational levels.esultshere were a total of 286 cases of breast cancer, and after adjustment for calendar year and age, the SIR was close to 1. When stratified by the year 1974 (the year in which the regulations on solvent use were promulgated), the SIR of the cohort of workers who were first employed prior to 1974 increased to 1.38 [95% confidence interval (CI): 1.11-1.70]. No such trend was discernible for workers employed after 1974. When 10 years of employment was considered, there was a further increase in the SIR for breast cancer, to 1.62. Those workers with breast cancer who were first employed prior to 1974 were employed at a younger age and for a longer period. Previous qualitative studies of interviews with the workers, corroborated by inspection records, showed a short-term high exposure to chlorinated alkanes and alkenes, particularly trichloroethylene before 1974. There were no similar findings on other types of cancer.ased on 11 exposed cases, the rate ratio (RR) of all malignant neoplasms was increased to 2.26 (95% CI: 1.12-4.54) among children whose mothers worked in this factory during periconceptional periods. The RRs were associated with six years or less (RR= 3.05; 95% CI: 1.20-7.74) and seven to nine years (RR= 2.49; 95% CI: 1.26-4.94) of education compared with ten years or more. An increased association was also found between childhood leukemia and exposed pregnancies (RR= 3.83; 95% CI: 1.17-12.55). he RR for infant mortality was increased to 2.71 [95% confidence interval (CI): 1.58‐4.64] among live born children whose fathers worked in this factory during preconception. Maternal delivering age less than 20 years, fathers with less than 10 years of education, and multiple births were associated with increased risks of infant mortality. When limited to 27 deaths with congenital malformation, Poisson regression model showed an increased risk for exposed pregnancies (RR = 3.69; 95% CI: 1.26-10.75), especially among cardiac defects (RR = 4.97; 95% CI: 1.55-15.89).onclusionsemale workers with exposure to trichloroethylene and/or mixture of solvents, first employed prior to 1974, may have an excess risk of breast cancer. Our study suggests that maternal occupation with potential exposure to organic solvents during periconception might increase risks of childhood cancers, especially for leukemia. Besides, paternal occupational exposures, possibly organic solvents during preconception, might increase infant mortality and deaths due to congenital malformation, especially for cardiac defects. However, the small numbers of this study limited its generalizability.
|Appears in Collections:||環境與職業健康科學研究所|
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