A case-referent study that investigated possible associations between environmental and occupational exposures and acute myeloid leukemia was performed on 86 cases and 172 referents, all of whom were living. Exposure information was obtained through a questionnaire mailed to each subject. An association was found between time spent in concrete buildings at home and work and leukemia morbidity. In addition, extensive x-ray examinations that occurred more than 5 y prior to diagnosis were more common among cases than referents.
Cancer has long been known to be a hazard of exposure to ionizing radiation. However, the assessment of health effects from exposure to radiation is a matter of considerable controversy. This paper presents results of a retrospective study of leukemia incidence (203-207, ICD-9) around the highest 137Cs pollution in Poland (as an effect of the Czarnobyl disaster and/or military bomb tests). The data relating to all the registered leukemias in males and females originated from the Regional Cancer Registry in Opole. The information on 137Cs concentration rates in Opole province was derived from the state monitoring provided by the Polish Geological Institute in Warsaw. The spatial analysis--based on the random-effects Poisson regression model--was carried out via the Markov Chain Monte Carlo (MCMC) technique (Gibbs sampling) using BUGS software. The model incorporated epidemiological data and an ecological covariate--isotope concentrations--and provided a framework for estimating the strength of a dose-response relationship. The differences in incidence levels were quantified by traditional standardized morbidity ratios (SMRs) and presented in thematic maps as well as in combined charts of distance-disease-dose relations. Additionally, to assess spatial disease clustering, a Tango test was adopted. The results of this ecological study suggest that the 137Cs concentrations did not have any negative influence on the exposed population.
The effect of potential risk factors for acute myeloid leukemia was evaluated in a case-referent study encompassing 59 cases and 354 referents, all of whom were alive. Information on exposure was obtained through a questionnaire mailed to the subjects. The possible effect of background radiation was evaluated by means of a gamma radiation index, which accounted for the differences between cases and referents in this respect, i.e., in time spent in concrete buildings both at home and at work places. In the 20-54 yr old age group, there was an association between leukemia morbidity and index of background radiation. X-ray treatment and electrical work were also associated with increased rate ratios. With regard to solvents, only styrene appeared as a risk factor, but the number of exposed subjects was small. Other exposures were less clearly associated with increased risks.
The accident which occurred during the night of April 25-26, 1986 in reactor 4 of the Chernobyl nuclear power plant in the Ukraine released considerable amounts of radioactive substances into the environment. Outside the former USSR, the highest levels of contamination were recorded in Bulgaria, Austria, Greece and Romania, followed by other countries of Central, Southeast and Northern Europe. Studies of the health consequences of the accident have been carried out in these countries, as well as in other countries in Europe. This report presents the results of a critical review of cancer studies of the exposed population in Europe, carried out on the occasion of the 10th anniversary of the Chernobyl accident. Overall, three is no evidence to date of a major public health impact of the Chernobyl accident in the field of cancer in countries of Europe outside the former USSR.
We estimated the radiation-induced risk of leukemia in 162,684 Chernobyl accident emergency workers (EWs) using the data of the Russian National Medical and Dosimetric Registry (RNMDR). A system was established for the collection and verification of data in 55 cases of leukemia from 1986 to 1995. The principal analysis included 41 leukemia cases that occurred more than 2 years after the first exposure to radiation. The case-control methodology was used to evaluate the risk of leukemia associated with various factors. Radiation dose, effective exposure dose rate, date of entry into the Chernobyl zone (ChZ), and the duration of stay in the zone were used as risk factors. The relationship between the date of entry and the duration of stay in the zone was investigated. All cases of leukemia, excluding chronic lymphocytic leukemia (CLL), were analyzed. An analysis was also performed on all EWs and on the EWs who worked in the zone from 1986 to 1987 (EWs of 1986 to 1987). No significant association was found between the risk of leukemia and the factors we investigated. Nevertheless, the relative risk estimates for leukemia, excluding CLL, were greater than the value for all leukemia and were greater than one. The estimated excess relative risk (ERR) per Gy was greater for all EWs [ERR = 1.33, 95% confidence interval (CI): -6.25, 8.90 for all leukemia, and ERR = 15.59, 95% CI: -24.92, 56.11 for leukemia, excluding CLL] compared with EWs of 1986 to 1987 (ERR = 0.28, 95% CI: -5.84, 7.41 for all leukemia, and ERR = 9.43, 95% CI: -20.0, 38.86 for leukemia, excluding CLL).
The Chernobyl nuclear accident on 26th April, 1986, led to a massive release of radionuclides into the environment. Although vast areas of Europe were affected by Chernobyl-related ionising radiation, the accident had the greatest impact in Belarus, Ukraine, and the Russian Federation. Epidemiological studies that have investigated the link between the Chernobyl accident and cancer have largely focused on malignant diseases in children, specifically thyroid cancer and leukaemia. There is good evidence to suggest that rates of thyroid cancer in children from the countries that were formally part of the Soviet Union have risen as a consequence of the Chernobyl accident. The findings for childhood leukaemia are less conclusive. Overall rates for this disease do not seem to have been affected by the Chernobyl-related ionising radiation, but there may be a larger risk of infant leukaemia in contaminated areas of Europe. Among adult populations, there is no strong evidence to suggest that risk of thyroid cancer, leukaemia, or other malignant disease has increased as a result of the Chernobyl accident.
An increased incidence of leukaemia and NHL has been recorded close to Britain's two nuclear reprocessing sites at Sellafield in West Cumbria and Dounreay in Northern Scotland. Two hypotheses have been advanced to explain the excesses - paternal preconceptional irradiation (PPI) and an infective basis promoted by population mixing. Subsequent studies have provided no support for the PPI hypothesis and have also shown that this was derived from the analysis of a sub-group. In contrast, support for the population mixing hypothesis has come from a series of studies of residential and occupational situations. One of these showed that the excess near Dounreay was part of a wider increase in rural areas of Scotland affected by the unusual mixing associated with away-from-home work in the North Sea oil industry, being more marked in areas of relatively high social class. It is probable that the excess in Seascale is due to related demographic factors, this parish being extreme in its high social class, geographic isolation and its proximity to Sellafield, the largest, most changing industrial site in rural Britain.
In studies of magnetic field exposure and childhood leukemia, power lines and other electrical installations close to the children's homes constitute the most extensively studied source of exposure. We conducted a study to assess whether exposure to magnetic fields in infant incubators is associated with an increased leukemia risk. We identified all children with leukemia born in Sweden between 1973 and 1989 from the national Cancer Registry and selected at random one control per case, individually matched by sex and time of birth, from the study base. We retrieved information about treatment in infant incubators from medical records. We made measurements of the magnetic fields inside the incubators for each incubator model kept by the hospitals. Exposure assessment was based on measurements of the magnetic field level inside the incubator, as well as on the length of treatment. For acute lymphoblastic leukemia, the risk estimates were close to unity for all exposure definitions. For acute myeloid leukemia, we found a slightly elevated risk, but with wide confidence intervals and with no indication of dose response. Overall, our results give little evidence that exposure to magnetic fields inside infant incubators is associated with an increased risk of childhood leukemia.
Individual biological dosimetry covering chromosomal analysis and electronic paramagnetic resonance spectrometry has been performed in 1300 subjects exposed to ionizing radiation after the Chernobyl accident. Cumulative radiation doses above 40 ImC were registered in 5%, about 100 ImC in 1% of the examinees. In 1% of cytogenetic investigations there appeared multiaberrant cells indicative of hot particle incorporation. Regional epidemiologists do not record changes in the incidence of hematological diseases. This may be explained by a small percent of the dose carriers, rare occurrence of hematological disorders and the time of radiation-induced oncogenic effects. The above representative group exposed to definite radiation doses may serve the subject of epidemiological surveys on the role of low-dose and low-rate radiation in pathogenesis of human diseases.