Leukaemia Incidence in Children and Adults in the Regions of Russia Most Highly Contaminated after the Chernobyl Nuclear Power Plant Accident

ABSTRACT BACKGROUND Leukaemia, especially the acute types predominant in children, may be caused by ionizing radiation. After the Chernobyl Nuclear Power Plant accident on 26 April 1986, parts of Belarus, Russia and the Ukraine were contaminated with radionuclides. To date, over 270 000 people live in such contaminated regions in Russia. This study investigates whether the leukaemia incidence rates in these regions might have increased due to the radiation. MATERIALS & METHODS A prospective population-based cohort study with a control group was carried out. Cases of leukaemia previously not registered were actively sought for in medical and administrative institutions. Each case that had occurred in the study regions between 1980 and 1998 has been ascertained and verified. A descriptive analysis was then performed on the resulting data base which included 333 leukaemia cases. RESULTS There is a slight secular trend in the standardized incidence rates both in the highly contaminated and in the control regions. This increase, however, is more marked in the control regions. The incidence rates in children (0-14) in the highly contaminated regions decrease between the pre-accident (1980 to 1986) and the first post-accident period (1987-1992) and show a slight increase towards the second post-accident period (1993-1998), whereas the incidence rates in the control regions show exactly the opposite dynamic. This makes a connection between the dynamics of the incidence rates and the radiological situation highly improbable. The comparative analysis of the leukaemia incidence rates has not revealed a statistically significant difference between the population of the highly contaminated regions of the Bryansk oblast and the combined control regions of the Kaluga oblast. CONCLUSIONS There is so far no indication of an increase in leukaemia incidence rates in the general population, neither for children nor for adults. This does not contradict the current radiobiological knowledge that cancer, especially leukaemia, can be caused by ionizing radiation. The number of expected radiation-induced cases based on the risk estimates from the Japanese cohort lies within the 95% confidence limits of the spontaneous incidence rates. It would therefore, if at all present, not be statistically detectable in a population of 222 000 with a spontaneous rate of 5.4/100 000 in men and 3.3/100 000 in women in the control regions. Considering the latency periods and the age-dependent risk-curve of radiation-induced cancers, it is highly unlikely that a radiation-related increase in leukaemia or solid tumour incidence rates will become obvious in the future. The fear and apprehension caused by the overestimation of the radiation risks create a continuous stress situation and add to the present detrimental health conditions in the population. It is therefore of utmost importance to communicate not only the results but also the reliability of the study and the soundness of the data to the affected people.

Level thesis:degree_level

thesis.doctoral

Grantor dc:publisher

Ludwig-Maximilians-Universität

Year

2003

Author dc:creator

• Becker, Susanne Isabel

Repository record source_url

https://edoc.ub.uni-muenchen.de/1853/

OAI identifier oai:identifier

oai:edoc.ub.uni-muenchen.de:1853