Occupational exposure and ovarian cancer risk
- 452 Downloads
Relatively little work has been done concerning occupational risk factors in ovarian cancer. Although studies conducted in occupational settings have reported positive associations, their usefulness is generally limited by the lack of information on important confounders. In a population-based case–control study, we assessed risk for developing epithelial ovarian cancer (EOC) associated with occupational exposure while accounting for important confounders.
Participants were identified through provincial population-based registries. Lifetime occupational history and information on potential confounding factors were obtained through a self-administered questionnaire. Unconditional logistic regression and the likelihood ratio test were used to assess EOC risk with each occupation (or industry), relative to all other occupations (or industries), adjusting for potential confounders including body mass index, oral contraceptive use, menopausal hormone therapy, parity, age at first childbirth, age at menarche, age at menopause, family history of breast and ovarian cancer in mother and sister(s), tubal ligation, partial oophorectomy, and hysterectomy. Occupations and industries were coded according to the Canadian Standard Occupational Classification (SOC) and Standard Industrial Classification (SIC).
Significant excess risk was observed for several groups of teaching occupations, including SOC 27, teaching and related (adjusted OR 1.77, 95 % CI 1.15–2.81) and SOC 279, other teaching and related (adjusted OR 3.11, 95 % CI 1.35–8.49). Significant excess was also seen for a four-digit occupational group SOC 4131, bookkeepers and accounting clerks (adjusted OR 2.80, 95 % CI 1.30–6.80). Industrial sub-groups showing significant excess risk included SIC 65, other retail stores (adjusted OR 2.19, 95 % CI 1.16–4.38); SIC 85, educational service (adjusted OR 1.45, 95 % CI 1.00–2.13); and SIC 863, non-institutional health services (adjusted OR 2.54, 95 % CI 1.13–6.52).
Our study found an elevated EOC risk for teaching occupations and is the first study to observe such an increased risk after adjustment for potential confounders. Further studies with more detailed assessment of the work environment and unique lifestyle characteristics may be fruitful in elucidating this etiology.
KeywordsEpithelial ovarian cancer Occupational risk Job history Case–control study
The authors thank two anonymous reviewers for their valuable comments and suggestions which led to an improved presentation of the paper. This research was partially supported by grants from WorkSafe BC (formerly the Workers’ Compensation Board of British Columbia). We gratefully acknowledge the invaluable contribution of the research coordinators and assistants: Barbara Jamieson, Donna Kan, Zenaida Abanto, and Lynn Vo.
Conflict of interest
The authors declare that they have no conflict of interest.
- 2.Ferlay J, Bray F, Pisani P, Parkin DM (2004) GLOBOCAN 2002: cancer incidence, mortality, and prevalence worldwide IARC Cancer Base No. 5. version 2.0, IARC Press, Lyon, France. http://www-dep.iarc.fr/
- 3.Canadian Cancer Statistics (2012) National Cancer Institute of Canada 2012Google Scholar
- 4.American Cancer Society (2012) Cancer facts and figures 2012. American Cancer Society, AtlantaGoogle Scholar
- 11.Rosenblatt KA, Thomas DB, Noonan EA (1992) High-dose and lowdose combined oral contraceptives: protection against epithelial ovarian cancer and the length of the protective effect. The WHO collaborative study of neoplasia and steroid contraceptives. Eur J Cancer 28A:1872–1876PubMedCrossRefGoogle Scholar
- 25.Teta MJ, Walrath J, Meigs JW, Flannery JT (1984) Cancer incidence among cosmetologists. J Natl Cancer Inst 5:1051–1057Google Scholar
- 26.Boffeta P, Andersen A, Lynge E et al (1994) Employment as hairdresser and risk of ovarian cancer and non-hodgkin’s lymphomas among women. J Occup Environ Med 36:61–65Google Scholar
- 30.Tzonou A, Polychronopoulou A, Hsieh C et al (1993) Hair dyes, analgesics, tranquilizers and perineal talc application as risk factors for ovarian cancer. Int J Cancer 55(408):410Google Scholar
- 34.Wagoner JK (1984) Leukemia and other malignancies following radiation therapy for gynecological disorders. In: Boice JD Jr, Fraumeni JF Jr (eds) Radiation carcinogenesis: epidemiology and biological significance. Raven Press, New YorkGoogle Scholar
- 41.Band PR, Spinelli JJ, Threlfall WJ, Fang R, Le DN, Gallagher RP (1999) Identification of occupational cancer risks in British Columbia. Part l: methodology, descriptive results, and analysis of cancer risks, by cigarette smoking categories of 15463 incident cancer cases. J Occup Environ Med 41:224–232PubMedCrossRefGoogle Scholar
- 42.Standard Occupational Classification 1980 (1981) Ottawa: Minister of Supplies and Services Canada (Statistics Canada Catalogue No 12-565E)Google Scholar
- 43.Standard Industrial Classification 1980 (1981) Ottawa: Minister of Supplies and Services Canada (Statistics Canada Catalogue No 12-501E)Google Scholar
- 44.Rothman KJ, Greenland S, Lask TL (2008) Modern epidemiology, 3rd edn. Lippincott Williams & Wilkins, PhiladephiaGoogle Scholar
- 45.Venables WN, Smith DM (2009) Introduction to R, 2nd Edition. Network Theory LimitedGoogle Scholar
- 46.Pukkala E (1995) Cancer risk by social class and occupation. A survey of 109,000 cancer cases among Finns of working age. Contrib Epidemiol Biostat Karger 7:63–76Google Scholar
- 47.Drewer F (1995) Occupational decennial supplement. Government Statistical Services. HMSO, LondonGoogle Scholar
- 48.California Teachers Study https://www.calteachersstudy.org/WebsiteGraphs.html#IDX4