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Occupational variation in the risk of female breast cancer in the Nordic countries

  • Sushmita Katuwal
  • Jan Ivar Martinsen
  • Kristina Kjaerheim
  • Pär Sparen
  • Laufey Tryggvadottir
  • Elsebeth Lynge
  • Elisabete Weiderpass
  • Eero Pukkala
Original paper
  • 33 Downloads

Abstract

Objective

This study aimed to determine occupational variations in the incidence of breast cancer in the population-based cohort of Nordic Occupational Cancer Study (NOCCA).

Methods

The study included long-term follow-up data from almost 7.5 million Nordic women. Participants were assigned to one of the 54 occupational categories based on census records at the ages of 30–64 years. Sixty-two thousand cases of breast cancer were identified through record linkages between nationwide cancer registries in Finland, Sweden, Norway, Denmark, and Iceland, followed up between 1961 and 2005. Country-specific standardized incidence ratios (SIRs) with 95% confidence intervals were estimated.

Results

Overall, the highest risk elevations were seen among military personnel (SIR 1.58, 95% CI 1.03–2.32), dentists (SIR 1.43, 95% CI 1.31–1.56), and physicians (SIR 1.35, 95% CI 1.26–1.46). The lowest risks were observed among gardeners (SIR 0.76, 95% CI 0.74–0.78), farmers (SIR 0.80, 95% CI 0.78–0.82), and woodworkers (SIR 0.75, 95% CI 0.70–0.81). Welders, tobacco workers, and painters had higher SIRs for breast cancer diagnosed at age < 50. A reduced risk was observed among forestry workers, welders, and fishery workers for breast cancers diagnosed both before and after age 50. The SIRs for breast cancer did not vary substantially by histology. A significantly increased risk of breast cancer was observed among laboratory workers in the latest calendar period (1991–2005) compared with earlier periods (1976–1990 and 1961–1975). Occupations such as farming, forestry, driving, and gardening had low SIRs during all periods.

Conclusions

The study suggests that the risk of breast cancer varies by occupation. Heterogeneity is also observed in some occupational categories according to age (before or after 50), histology, and calendar period.

Keywords

Breast cancer Nordic Occupational exposure Risk factors 

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Copyright information

© Springer Nature Switzerland AG 2018

Authors and Affiliations

  • Sushmita Katuwal
    • 1
  • Jan Ivar Martinsen
    • 2
  • Kristina Kjaerheim
    • 2
  • Pär Sparen
    • 6
  • Laufey Tryggvadottir
    • 7
    • 8
  • Elsebeth Lynge
    • 9
  • Elisabete Weiderpass
    • 2
    • 3
    • 4
    • 5
    • 6
  • Eero Pukkala
    • 1
    • 10
  1. 1.Faculty of Social SciencesUniversity of TampereTampereFinland
  2. 2.Department of Research, Cancer Registry of NorwayInstitute of Population-Based Cancer ResearchOsloNorway
  3. 3.Department of Community Medicine, Faculty of Health SciencesUniversity of TromsøTromsøNorway
  4. 4.Genetic Epidemiology GroupFolkhälsan Research CentreHelsinkiFinland
  5. 5.Faculty of MedicineHelsinki UniversityHelsinkiFinland
  6. 6.Department of Medical Epidemiology and BiostatisticsKarolinska InstitutetStockholmSweden
  7. 7.Icelandic Cancer RegistryReykjavikIceland
  8. 8.Faculty of MedicineUniversity of IcelandReykjavikIceland
  9. 9.Centre for Epidemiology and Screening, Institute of Public HealthUniversity of CopenhagenCopenhagenDenmark
  10. 10.Finnish Cancer RegistryInstitute for Statistical and Epidemiological Cancer ResearchHelsinkiFinland

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