American Journal of Epidemiology Advance Access originally published online on May 29, 2007
American Journal of Epidemiology 2007 166(2):239-240; doi:10.1093/aje/kwm166
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LETTERS TO THE EDITOR |
RE: "CHROMOSOMAL ABERRATIONS AND CANCER RISK: RESULTS OF A COHORT STUDY FROM CENTRAL EUROPE"
Radiation Epidemiology Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Department of Health and Human Services, Bethesda, MD 20852
(e-mail: chodickg{at}mail.nih.gov; hodik_g{at}mac.org.il)
We read with interest the study reported on by Boffetta et al. (1) that provides an additional, large population informative for the association between frequency of chromosomal aberrations and subsequent cancer risk. One of their findings was that exposure to ionizing radiation increases the association between chromosomal aberrations and risk of cancer. However, we have some concerns with the authors' statement. First, the differences in the relative risk of cancer among individuals exposed to radiation compared with the entire study population were relatively small and, as mentioned by the authors, there was no statistically significant interaction, so the results can therefore be explained by chance alone. Second, exposure to ionizing radiation is positively associated with structural chromosome aberrations and increased risk of cancer; thus, the study results presented in table 3 (1, p. 40) may not necessarily suggest an interaction at all but reflect the known usefulness of structural chromosome aberrations as a biomarker of radiation exposure (2). Although the authors cautiously speculate about the role of individual genetic susceptibility, they used only a dichotomous radiation exposure variable and could not support more robust explorations of an interaction with radiation exposure, chromosome aberration tertile, and cancer risk. As stated by the authors, a careful evaluation of the presence of confounding due to host factors or external genotoxic exposures is essential in investigating the association between chromosomal damage and risk of cancer. Other than age, we feel that the study was largely uninformative with respect to the contribution of underlying genetics versus occupational exposures on the frequency of chromosome aberrations and the association with subsequent cancer risk.
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ACKNOWLEDGMENTS |
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Conflict of interest: none declared.
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NOTES |
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Editor's note: In accordance with Journal policy, Boffetta et al. were asked whether they wanted to respond to this letter, but they chose not to do so.
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References |
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 TOP References |
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- Boffetta P, van der Hel O, Norppa H, et al. Chromosomal aberrations and cancer risk: results of a cohort study from central Europe. Am J Epidemiol (2007) 165:36–43.
[Abstract/Free Full Text] - Edwards AA, Lindholm C, Darroudi F, et al. Review of translocations detected by FISH for retrospective biological dosimetry applications. Radiat Prot Dosimetry (2005) 113:396–402.
[Abstract/Free Full Text]
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