IJE Advance Access originally published online on November 3, 2005
International Journal of Epidemiology 2006 35(2):386-396; doi:10.1093/ije/dyi220
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Article |
Childhood leukaemia in Belarus, Russia, and Ukraine following the Chernobyl power station accident: results from an international collaborative population-based case–control study
1 Division of Public Health Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA, USA.
2 School of Public Health and Community Medicine, University of Washington, Seattle, WA, USA.
3 Roswell Park Cancer Institute, Buffalo, NY, USA.
4 Medical Radiological Research Center, Obninsk, Russia.
5 MJP Risk Assessment, Inc., Denver, CO, USA.
6 Belarussian–Russian University, Mogilev, Belarus.
7 National Hematology Research Center, Moscow, Russian Federation.
8 Sakharov International State Ecological University, Minsk, Belarus.
9 Regional Diagnostic Center, Bryansk, Russia.
10 Committee on problems of consequences of disaster of Chernobyl nuclear power station, Council of Ministers of Belarus, Minsk, Belarus.
* Corresponding author. Fred Hutchinson Cancer Research Center, 1100 Fairview Avenue N, M4-B874, PO Box 19024, Seattle, WA 98109-1024, USA. E-mail: sdavis{at}fhcrc.org
Background There is little evidence regarding the risk of leukaemia in children following exposure to radionuclides from the Chernobyl Nuclear Power Plant explosion on April 26, 1986.
Methods This population-based case–control study investigated whether acute leukaemia is increased among children who were in utero or <6 years of age at the time of the Chernobyl accident. Confirmed cases of leukaemia diagnosed from April 26, 1986 through December 31, 2000 in contaminated regions of Belarus, Russia, and Ukraine were included. Two controls were matched to each case on sex, birth year, and residence. Accumulated absorbed radiation dose to the bone marrow was estimated for each subject.
Results Median estimated radiation doses of participants were <10 mGy. A significant increase in leukaemia risk with increasing radiation dose to the bone marrow was found. This association was most evident in Ukraine, apparent (but not statistically significant) in Belarus, and not found in Russia.
Conclusion Taken at face value, these findings suggest that prolonged exposure to very low radiation doses may increase leukaemia risk as much as or even more than acute exposure. However the large and statistically significant dose–response might be accounted for, at least in part, by an overestimate of risk in Ukraine. Therefore, we conclude this study provides no convincing evidence of an increased risk of childhood leukaemia as a result of exposure to Chernobyl radiation, since it is unclear whether the results are due to a true radiation-related excess, asampling-derived bias in Ukraine, or some combination thereof. However, the lack of significant dose–responses in Belarus and Russia also cannot convincingly rule out the possibility of an increase in leukaemia risk at low dose levels.
Keywords Childhood leukaemia, radiation, Chernobyl, individual dosimetry
Accepted 29 September 2005