Occupational magnetic fields and female breast cancer: a case-control study using Swedish population registers and new exposure data.
Several recent epidemiologic studies on occupational magnetic field exposure have suggested an association with female breast cancer. The purpose of this study was to test this hypothesis by using the extensive Swedish population registers in combination with improved exposure assessment. The study base consisted of all women between 1976 and 1999 gainfully employed in Stockholm or Gotland County in Sweden. A total of 20,400 cases of breast cancer were identified from the cancer registry, and 116,227 controls were selected randomly from the study base. Information was available on estrogen receptor status, occupation, socioeconomic status, and age. Parity was available for a subset. The exposure was assessed by linkage to a newly developed job-exposure matrix based on personal magnetic field measurements on women. All risk estimates were close to unity regardless of exposure cutpoint or choice of exposure parameter. The overall odds ratio for women exposed to 0.30 microT or more was 1.01 (95% confidence interval: 0.93, 1.10). The size of the study allowed for estimates with good precision also in subgroups where previous studies have suggested increased risk, but the findings do not support the hypothesis that magnetic fields influence the risk of female breast cancer.
Forssén
Ulla M
UM
Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden. ulla.forssen@imm.ki.se
Rutqvist
Lars Erik
LE
Ahlbom
Anders
A
Feychting
Maria
M
D000328:Adult; D001943:Breast Neoplasms / Q000453:epidemiology / Q000209:etiology*; D016022:Case-Control Studies; D015986:Confounding Factors, Epidemiologic; D004574:Electromagnetic Fields / Q000009:adverse effects*; D005260:Female; D006801:Humans; D016015:Logistic Models; D008875:Middle Aged; D016273:Occupational Exposure / Q000009:adverse effects*; D010298:Parity; D012042:Registries; D012307:Risk Factors; D012923:Social Class; D013548:Sweden / Q000453:epidemiology