Incidence of selected cancers in Swedish railway workers, 1961-79.
Published in: Cancer Causes Control 1994; 5 (2): 189-194
Aim of study (acc. to author)
The present study is a re-analysis of the study of Floderus et al (1993) in which the 1961-1979 incidence data showed no increase in risk for leukemia and brain tumors for railway workers. In the present study, follow-up was divided into two 10-year periods 1961-1969 and 1970-1979 because the structural change in the railway industry could mean that a large proportion of subjects in the exposure groups was exposed to high levels of EMF only during the very first period, and that this could dilute a potential effect.
Endpoint/type of risk estimation
engine drivers and conductors
railway workers (station masters, train dispatcher, railroad assistants and linemen)
workers in the railway industry
railway workers employed in 1960
1960 - 1979
Cancer Environment Registry
Conclusion (acc. to author)
Overall, there seem to be elevated estimates for the exposure groups during the first decade, which are not seen during the second period of follow-up.
For the first decade 1961-1969, engine drivers and conductors combined had an relative risk (RR) of 1.9 (CI 0.9-4.0) for chronic lymphocytic leukemia, of 1.4 (CI 0.4-4.3) for acute myeloid leukemia, and 1.0 (CI 0.5-1.9) for lymphoma. For all brain tumors, the RR was 1.2 (CI 0.8-1.9), with a higher risk estimate for those below age 30 (RR 12.2, CI 2.8-52.5). Three cases of breast cancer and nine cases of tumors of the pituitary gland occurred among engine drivers and conductors (RR 4.9, CI 1.6-11.8; RR 3.2, CI 1.6-6.2, respectively).
The authors conclude that the results give some support to the hypothesis of an association between EMF and certain types of cancers in railway workers.
Limitations (acc. to author)
Occupation was only defined at baseline in 1960, therefore a potential occupational change is not incorporated.
Study funded by
National Board of Occupational Safety and Health; Sweden
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