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PubMed2004

Molecular aspects of plant adaptation to life in the Chernobyl zone.

With each passing year since the Chernobyl accident of 1986, more questions arise about the potential for organisms to adapt to radiation exposure. Often this is thought to be attributed to somatic and germline mutation rates in various organisms. We analyzed the adaptability of native Arabidopsis plants collected from areas with different levels of contamination around the Chernobyl nuclear power plant from 1986 to 1992. Notably, progeny of Chernobyl plants resisted higher concentrations of the mutagens Rose Bengal and methyl methane sulfonate. We analyzed the possible molecular mechanisms of their resistance to mutagens and found a more than 10-fold lower frequency of extrachromosomal homologous recombination, significant differences in the expression of radical scavenging (CAT1 and FSD3) and DNA-repair (RAD1 and RAD51-like) genes upon exposure to mutagens (Rose Bengal and x-rays), and a higher level of global genome methylation. This data suggests that adaptation to ionizing radiation is a complex process involving epigenetic regulation of gene expression and genome stabilization that improves plants' resistance to environmental mutagens.

Adaptation, Physiological↗

PubMed1993

The Chernobyl accident, congenital anomalies and other reproductive outcomes.

Studies of the association between the Chernobyl accident in April 1986 and reproductive outcome, with particular reference to congenital anomalies, are reviewed. All of the studies so far have been based on the detection of a change in frequency over time. An increased frequency of trisomy 21 in the former West Berlin in January 1987, and increases in the frequency of neural tube defects in several small hospital-based series in Turkey, are not confirmed in larger and more representative series in Europe. No clear changes in the prevalence at birth of anomalies which might be associated with the accident are apparent in Byelorussia or the Ukraine, the republics with the highest exposure to fallout. However, these data are difficult to interpret as the methods of acquisition have not been described and they have not yet been reported in full. Thus, there is no consistent evidence of a detrimental physical effect of the Chernobyl accident on congenital anomalies. This is also the case for other measured outcomes of pregnancy. There is evidence of indirect effects--an increase in induced abortions substantial enough to show as a reduction in total births, due to anxieties created. Data are not available on the reproductive outcomes of women pregnant at the time of the accident who were evacuated from the 30 km zone of immediate contamination, of workers in the plant at the time of the accident or of decontamination workers. Moreover, no data are available from several of the other countries closest to the Chernobyl area.

Abortion, Induced↗

PubMed2005

Uncertainty and sensitivity analysis in assessment of the thyroid cancer risk related to Chernobyl fallout in Eastern France.

The increase in the thyroid cancer incidence in France observed over the last 20 years has raised public concern about its association with the 1986 nuclear power plant accident at Chernobyl. At the request of French authorities, a first study sought to quantify the possible risk of thyroid cancer associated with the Chernobyl fallout in France. This study suffered from two limitations. The first involved the lack of knowledge of spontaneous thyroid cancer incidence rates (in the absence of exposure), which was especially necessary to take their trends into account for projections over time; the second was the failure to consider the uncertainties. The aim of this article is to enhance the initial thyroid cancer risk assessment for the period 1991-2007 in the area of France most exposed to the fallout (i.e., eastern France) and thereby mitigate these limitations. We consider the changes over time in the incidence of spontaneous thyroid cancer and conduct both uncertainty and sensitivity analyses. The number of spontaneous thyroid cancers was estimated from French cancer registries on the basis of two scenarios: one with a constant incidence, the other using the trend observed. Thyroid doses were estimated from all available data about contamination in France from Chernobyl fallout. Results from a 1995 pooled analysis published by Ron et al. were used to determine the dose-response relation. Depending on the scenario, the number of spontaneous thyroid cancer cases ranges from 894 (90% CI: 869-920) to 1,716 (90% CI: 1,691-1,741). The number of excess thyroid cancer cases predicted ranges from 5 (90% UI: 1-15) to 63 (90% UI: 12-180). All of the assumptions underlying the thyroid cancer risk assessment are discussed.

Adolescent↗

PubMed1994

Significant increase in trisomy 21 in Berlin nine months after the Chernobyl reactor accident: temporal correlation or causal relation?

OBJECTIVE: To assess whether the increased prevalence of trisomy 21 in West Berlin in January 1987 might have been causally related to exposure to ionising radiation as a result of the Chernobyl reactor accident or was merely a chance event. DESIGN: Analysis of monthly prevalence of trisomy 21 in West Berlin from January 1980 to December 1989. SETTING: Confines of West Berlin. RESULTS: Owing to the former "island" situation of West Berlin and its well organised health services, ascertainment of trisomy 21 was thought to be almost complete. A cluster of 12 cases occurred in January 1987 as compared with two or three expected. After exclusion of factors that might have explained the increase, including maternal age distribution, only exposure to radiation as a result of the Chernobyl reactor accident remained. In six of seven cases that could be studied cytogenetically the extra chromosome was of maternal origin, confirming that nondisjunction had occurred at about the time of conception. CONCLUSION: On the basis of two assumptions--(a) that maternal meiosis is an error prone process susceptible to exogenous factors at the time of conception; (b) that owing to the high prevalence of iodine deficiency in Berlin a large amount of iodine-131 would have been accumulated over a short period--it is concluded that the increased prevalence of trisomy 21 in West Berlin in January 1987 was causally related to a short period of exposure to ionising radiation as a result of the Chernobyl reactor accident.

Accidents↗

PubMed1996

Fibrosarcoma of the thyroid in a man exposed to fallout from the Chernobyl accident.

Since the Chernobyl accident in April 1986, a dramatic increase in the incidence of thyroid carcinoma has been described, especially in children. A case of sarcoma of the thyroid in a man exposed to the Chernobyl fallout is presented. Sarcoma of the thyroid is a rare finding. The present patient lived in a region that is known to be one of the most exposed to Chernobyl fallout. The case suggests a high probability of a relationship between the sarcoma of the thyroid and the exposure to radiation.

Aged↗

PubMed1994

Trends and geographical distribution of childhood leukemia in Greece in relation to the Chernobyl accident.

Parts of Greece have been exposed to fallout radiation from the Chernobyl accident as much as any of the countries boardering with the former Soviet Union, because of the direction of the prevailing winds after the accident. Although fallout radiation did not reach levels expected to be associated with measurable effects, there is widespread concern in Greece that the incidence of childhood leukemia may be rising in the more heavily affected parts of Greece. Patient discharge data from all Greek hospitals treating childhood leukemia were used to calculate the annual incidence of the disease from January 1980 to June 1986 (preaccident period), from July 1986 to June 1988 (immediate postaccident period) and from July 1988 to June 1991 ("relevant" post-accident period, that accommodates the presumed latent period of the disease). Fallout radiation measurements (in Bq/kg Cs-137) were used to create 17 regions of similar (within regions) but highly variable (between regions) levels of fallout deposition. Background radiation (in Bq/kg Ra-226) and annual incidence of childhood leukemia by region were also estimated. There was no evidence of increased incidence of childhood leukemia during the immediate or the "relevant" post-Chernobyl period in any part of the country. Furthermore, regression analyses did not show any significant or suggestive association of childhood leukemia by region with either background or fallout radiation. These results indicate that the Chernobyl accident did not affect noticeably the incidence of childhood leukemia in Greece during the five-year post accident period.

Accidents↗

PubMed2004

Heterogeneity in the distribution of RET/PTC rearrangements within individual post-Chernobyl papillary thyroid carcinomas.

The nuclear disaster that occurred in Chernobyl in 1986 offered the unique opportunity to study the molecular genetics of one human tumor type, papillary carcinoma of the thyroid gland, associated with a specific etiology. We have analyzed RET rearrangements in post-Chernobyl papillary thyroid carcinomas (n = 29), follicular thyroid adenomas (n = 2), and follicular thyroid carcinoma (n = 1) by interphase fluorescence in situ hybridization (FISH) analysis on paraffin-embedded tissue sections. Paraffin sections were microdissected before use to ensure that only tumor was present. Cell nuclei were scored for the presence of a split FISH signal (separated red and green signal) in addition to an overlapping signal. Only cells with either two overlapping signals or one split and one overlapping signal were counted to ensure that only complete cell nuclei had been scored. In total, 23 of 32 cases (72%) showed RET rearrangements diagnosed by FISH interphase analysis. In all cases, the tumors were composed of a mixture of cells with and without ret rearrangement on FISH. In some cases, this distribution was clearly nonrandom because clustering of rearranged cells was detected within the same tumor nodule. Accordingly, only 31% of the cases positive for rearrangement on FISH also scored positive using RT-PCR. These findings suggest that because RET/PTC rearrangements are not present in a majority of tumor cells, either a fraction of post-Chernobyl papillary thyroid tumors are of multiclonal origin, or ret rearrangement is a later, subclonal event.

Adolescent↗

PubMed1997

Post-Chernobyl thyroid carcinoma in Belarus children and adolescents: comparison with naturally occurring thyroid carcinoma in Italy and France.

After the Chernobyl nuclear accident (April 26, 1986), childhood thyroid carcinoma had a great increase in Belarus and Ukraine, as a consequence of the exposure to iodine radioactive fallout. The epidemiological and clinical features of the disease were studied in 472 patients less than 21 yr old at diagnosis, with differentiated thyroid carcinoma, representing 97.7% of all thyroid carcinomas diagnosed in Belarus between May, 1986, and December, 1995. The results were compared with those of 369 subjects of the same age group, with naturally occurring thyroid carcinoma, observed in Italy and France. Between 1986 and 1989, the number of thyroid cancer cases per year ranged from 3-8 and increased to 31 in 1990, to 66 in 1991, to 72 in 1992, to 93 in 1993, to 96 in 1994, and to 90 in 1995. The age at diagnosis was 14 yr or less in 78.8% (children group) and more than 14, but less than 21, yr in the remaining subjects (adolescents group). Mean (+/- SD) age at the time of the accident was 4.4 +/- 3.4 yr (3.2 +/- 2.3 in children and 8.9 +/- 2.7 in adolescents), the majority of the patients (62.9%) being 5 yr old or less. The time interval between the accident and the diagnosis (latency period) decreased progressively from 7.5 +/- 1.6 yr in children 0-2 yr old at the time of the accident to 6.0 +/- 1.6 yr in those 9-11 yr old. Since 1993, the yearly distribution of new cases showed a decrease in the subjects 9 yr old or more at the time of the accident but not in those 5 yr old or less. This could not be accounted for by a shift of exposed subjects to an age group at diagnosis not included in this study, because only subjects less than 12 yr of age at the time of the accident were considered in this analysis. Mean age at diagnosis in Belarus patients was 11.3 +/- 3.1 yr (10.1 +/- 2.3 in children and 15.7 +/- 1.4 in adolescents), whereas, among patients with naturally-occurring thyroid carcinomas from Italy and France, the majority of cases were diagnosed after 14 yr of age (mean age at diagnosis: 14.6 +/- 4.2 yr). The female-to-male ratio was significantly higher in Italy and France (2.5/1), compared with the ratio of patients from Belarus (1.6/1). Most of the tumors were papillary in both series, but a relatively high proportion of follicular carcinomas (P = 0.0001) was found in Italy/France (15.2%), as opposed to 5.3% in Belarus. Extrathyroidal extension and lymph node metastases were more frequent in Belarus (49.1%, P = 0.0001; and 64.6%, P = 0.002, respectively) with respect to Italy/France (24.9% and 53.9%, respectively). Thyroid lymphocytic infiltration and circulating antithyroperoxidase antibody were more frequent in Belarus patients. Our analysis of Belarus thyroid cancer patients less than 21 yr old showed that the post-Chernobyl increase in thyroid carcinomas involved both children and, to a much lesser extent, adolescents. Subjects 5 yr old or less at the time of the accident accounted for the majority of the patients. No evidence of a decrease in the number of new cases was observed in this age group, as opposed to older subjects. These data support the concept that subjects who were younger at the time of radiation exposure had, and continue to have, a greater risk of developing thyroid carcinoma and strongly suggest that this age group should be carefully monitored in the future. When compared with naturally occurring thyroid carcinoma of the same age group observed in Italy and France, the post-Chernobyl Belarus thyroid carcinomas affected younger subjects, were less influenced by gender, were virtually always papillary, had a greater aggressiveness at presentation, and were more frequently associated with thyroid autoimmunity.

Adenocarcinoma, Follicular↗

PubMed2001

Chernobyl fallout and outcome of pregnancy in Finland.

Possible effects of Chernobyl fallout on outcome of pregnancy in Finland were evaluated in a nationwide follow-up study. The outcomes were the rate of live births and stillbirths, pregnancy loss, and induced abortions by municipality. Exposure was assessed based on nationwide surveys of radiation dose rate from the Chernobyl fallout, from both external and internal exposures. Using these measurements, we estimated the monthly dose rate for each of the 455 Finnish municipalities. On average, the dose rate from Chernobyl fallout reached 50 microSv per month in May 1986--a doubling of the natural background radiation. In the most heavily affected area, 4 times the normal background dose rates were recorded. Given the underlying regional differences in live birth, stillbirth, and abortion rates, we used longitudinal analysis comparing changes over time within municipalities. A temporary decline in the live birth rate had already begun before 1986, with no clear relationship to the level of fallout. A statistically significant increase in spontaneous abortions with dose of radiation was observed. No marked changes in induced abortions or stillbirths were observed. The decrease in the live birth rate is probably not a biological effect of radiation, but more likely related to public concerns of the fallout. The effect on spontaneous abortions should be interpreted with caution, because of potential bias or confounding. Further, there is little support in the epidemiologic literature on effects of very low doses of radiation on pregnancy outcome.

Abortion, Spontaneous↗

PubMed1997

Chernobyl-related thyroid cancer: what evidence for role of short-lived iodines?

Over 500 cases of thyroid cancer were diagnosed in Belarus between 1986 and 1995 among persons exposed as children (under 15 years of age) to radioactive contamination from the Chernobyl nuclear accident. There is little doubt that radioactive iodine isotopes emitted during the nuclear explosion and subsequent fire were instrumental in causing malignancy in this particular organ. Comparison of the observed geographic distribution of Chernobyl-associated thyroid cancer incidence rates by districts with contamination maps of radioactive fallout shows a better fit for estimated 131I contamination than for 137Cs. Because 131I used for medical purposes had not been considered carcinogenic in humans in the past, and in view of the unusually short latency period between exposure and clinical manifestation of cancer, it is suspected that not only 131I but also energy-rich shorter-lived radioiodines may have played a role in post-Chernobyl thyroid carcinogenesis. Measurements of iodine isotopes are not available, but reconstruction of geographic distributions and estimations of radioactive fallout based on meteorological observations immediately following the accident could provide a basis for comparison with the distribution of thyroid cancer cases. In this paper, data from the Epidemiological Cancer Register for Belarus will be used to show geographic and time trends of thyroid cancer incidence rates in the period from 1986 to 1995 among persons who were exposed as children, and these will be compared with the estimated contamination by radioiodines. Tentative conclusions are drawn from the available evidence and further research requirements discussed.

Adolescent↗

PubMed1997

Health effects of the Chernobyl disaster: illness or illness behavior? A comparative general health survey in two former Soviet regions.

Results are described of a general health survey (n = 3044) that was conducted 6.5 years after the Chernobyl accident in 1986 in a seriously contaminated region in Belarus and a socioeconomically comparable, but unaffected, region in the Russian Federation. The purpose of the study was to investigate whether there are differences in the general health status of the inhabitants of the two regions that may be attributed to the Chernobyl disaster. A broad-based population sample from each of these regions was studied using a variety of self-report questionnaires. A subsample (n = 449) was further examined with a standardized physical and psychiatric examination. The results show significantly higher scores on the self-report questionnaires and higher medical service utilization in the exposed region. No significant differences were observed in global clinical indices of health. Although there were trends for some disorders to be more prevalent in the exposed region, none of these could be directly attributed to exposure to ionizing radiation. The results of this study suggest that the Chernobyl disaster had a significant long-term impact on psychological well-being, health-related quality of life, and illness behavior in the exposed population.

Adolescent↗

PubMed1997

Two-year follow up study of stress-related disorders among immigrants to Israel from the Chernobyl area.

We report on findings from a 2-year follow-up study of immigrants originating from exposed areas around the site of the 1986 Chernobyl accident matched with comparison subjects emigrating from other republics in the Confederation of Independent States. In the initial study of 708 immigrants, the samples were matched by age, gender, and year of immigration. We assessed two exposure groups--high and low--by estimating levels of ground cesium contamination from the International Atomic Energy Agency maps. We reinterviewed 520 immigrants from the first wave of data collection (a reinterview rate of 73%), 87 from high-exposure areas, 217 from low-exposure areas, and 216 comparison subjects. This study examined the prevalence of symptoms of posttraumatic stress disorders (PTSD), depression, somatization, anxiety, and physical effects (high blood pressure, acute symptoms, and chronic illness). The results obtained in the first wave conducted 8 years after the accident showed that psychological symptoms were significantly higher in exposed respondents than in the comparison group. During the second wave (10 years after the accident) we observed a decline in the prevalence of PTSD and related distress except for somatization, which remained at the same level. An association between exposure and high blood pressure was observed in the first wave of data, but was not still significant in the second wave of data collection. The proportion of those who reported three or more chronic health problems was 48.3% among the high-exposure group, 49.3% in the low-exposure group, and 30.6% in the comparison group (p = 0.0003). The most commonly reported problems were heart disease. problems with vision or hearing, migraine headaches, problems with the lymphatic system, and arthritis. Based on the results, it was concluded that the Chernobyl accident was a powerful stressor, having a strong impact on both mental and physical health. Since all respondents were engaged in the process of acculturation and accommodation to a new country after emigration, it is encouraging that this study shows that levels of psychological distress are waning as the new immigrants are absorbed into Israeli society. However, there still remains some independent effect on health associated with the experience of the Chernobyl accident.

Adult↗

PubMed2001

Urinary iodine levels and thyroid diseases in children; comparison between Nagasaki and Chernobyl.

We evaluated the incidence of childhood thyroid diseases and urinary iodine levels in Nagasaki, Japan and in Gomel, Belarus, which was greatly radio-contaminated by the Chernobyl accident, in order to obtain the comparative data of thyroid diseases between iodine-rich (Japan) and -deficient (Belarus) areas. In Nagasaki, the median level of urinary iodine, measured by ammonium persulfate digestion in microplate method, was 362.9 microg/L. In order to evaluate the geographical differences in Japan, other samples were collected in Hamamatsu and in South Kayabe, Hokkaido, where the median levels were 208.4 microg/L and 1015.5 microg/L, respectively. Furthermore, thyroid screening by ultrasound (US) in Nagasaki revealed only four cases that showed goiter (1.6%) and two cases (0.8%) that had cystic degeneration and single thyroid cyst. There was no evidence of thyroid nodule detected by US examination. In contrast, the median of urinary iodine level was 41.3 microg/L in Gomel. The incidences of goiter (13.6%) and echogenic abnormality (1.74%) in Gomel were much higher than in Nagasaki, suggesting the critical involvement of iodine deficiency in increased childhood thyroid abnormality around Chernobyl. Radioactive iodine released just after the Chernobyl accident may have influenced predominantly children residing in iodine-deficient areas. Our results suggest that management of thyroid screening for schoolchildren at ordinary times may be beneficial for monitoring the adverse effects of radioactive iodine from the standpoint of future prospective study.

Adolescent↗

PubMed2002

Three somatic genetic biomarkers and covariates in radiation-exposed Russian cleanup workers of the chernobyl nuclear reactor 6-13 years after exposure.

Three somatic mutation assays were evaluated in men exposed to low-dose, whole-body, ionizing radiation. Blood samples were obtained between 1992 and 1999 from 625 Russian Chernobyl cleanup workers and 182 Russian controls. The assays were chromosome translocations in lymphocytes detected by FISH, hypoxanthine phosphoribosyltransferase (HPRT) mutant frequency in lymphocytes by cloning, and flow cytometic assay for glycophorin A (GPA) variant frequency of both deletion (N/Ø) and recombination (N/N) events detected in erythrocytes. Over 30 exposure and lifestyle covariates were available from questionnaires. Among the covariates evaluated, some increased (e.g. age, smoking) and others decreased (e.g. date of sample) biomarker responses at a magnitude comparable to Chernobyl exposure. When adjusted for covariates, exposure at Chernobyl was a statistically significant factor for translocation frequency (increase of 30%, 95% CI of 10%-53%, P = 0.002) and HPRT mutant frequency (increase of 41%, 95% CI of 19%-66%, P < 0.001), but not for either GPA assay. The estimated average dose for the cleanup workers based on the average increase in translocations was 9.5 cGy. Translocation analysis is the preferred biomarker for low-dose radiation dosimetry given its sensitivity, relatively few covariates, and dose-response data. Based on this estimated dose, the risk of exposure-related cancer is expected to be low.

Adult↗

PubMed2003

Chromosome alterations in cleanup workers sampled years after the Chernobyl accident.

Cytogenetic analysis performed 4-13 years after the Chernobyl accident showed an elevated frequency of acentrics, chromatid exchanges, dicentrics and rings in Chernobyl cleanup workers compared to the control group. Cytogenetic data were analyzed according to the information on exposure to radiation (the year when the cleanup workers worked at the Chernobyl station, doses rates, time elapsed since exposure to radiation, and cytogenetic examination) and some lifestyle factors. The data obtained suggested that some types of chromosome aberrations could be influenced by the action of different environmental factors or lifestyle factors. The frequency of acentrics was correlated with the age of the cleanup workers, and the increased chromatid exchange frequency was attributed to smoking. The numbers of dicentrics and rings suggested a genotoxic effect of ionizing radiation that is still present over 13 years after the exposure.

Chromosome Aberrations↗

PubMed2005

ret/PTC1 and ret/PTC3 in thyroid tumors from Chernobyl liquidators: comparison with sporadic tumors from Ukrainian and French patients.

Like children exposed to Chernobyl fallout, the workers who cleaned up after the accident, also known as liquidators, have exhibited an increased incidence of thyroid cancer. A high prevalence of ret/PTC3 rearrangement has been found in pediatric post-Chernobyl thyroid tumors, but this feature has not been investigated in liquidator thyroid tumors. In this study we analyzed the prevalence of ret/PTC1 and ret/PTC3 in thyroid tumors from 21 liquidators, 31 nonirradiated adult Ukrainian patients, and 34 nonirradiated adult French patients. ret rearrangements in carcinomas were found in 83.3% of liquidators, 64.7% of Ukrainian patients, and 42.9% of French patients. The prevalence of ret/PTC1 was statistically similar in the three groups. The prevalence of ret/PTC3 was significantly higher in liquidators than in French patients (P = 0.03) but it was also high in nonirradiated Ukrainian patients who exhibited values intermediate between liquidators and French patients. In adenomas the prevalence of rearrangement was significantly higher in all Ukrainians than in French patients (P = 0.004). Like children exposed to Chernobyl fallout, liquidators showed a high prevalence of ret/PTC3. This finding suggests that irradiation had the same effect regardless of age. However, given the high rate of ret/PTC3 in nonirradiated adult Ukrainians, the possibility of genetic susceptibility or low-level exposure to radiation in that group cannot be excluded.

Adult↗

PubMed1996

Ten years after Chernobyl.

This review focuses on current findings on the health consequences of the accident at the Chernobyl nuclear power plant in 1986. Acute radiation damage caused by exposure to high doses of ionizing radiation involved a few hundred people, apparently with fewer than 100 deaths within the first few months. Epidemiologically detectable increases in congenital abnormalities have not been reported thus far, with the possible exception of Down's syndrome. Owing to the long latency period of radiation-induced cancer, discernible increases in cancer incidence and mortality are not yet expected for most tumour types, especially among adults. However, dramatic increases in the number of childhood thyroid cancers have already been observed in Belarus and Ukraine and the Bryansk regions of Russia. The increase has been over 100-fold in some areas with heavy contamination. From the viewpoint of overall public health, the outlook of direct health effects of the Chernobyl accident are likely to be severe only among some limited subgroups, such as young children exposed to high levels of fallout nuclides. In absolute terms, the global number of Chernobyl-associated cancer cases can be estimated to be tens of thousands, but only a small fraction of these is likely to be discernible epidemiologically.

Abnormalities, Radiation-Induced↗

PubMed1999

[The morphological status of the maxillodental system in children living in an area contaminated by radionuclides as a result of the accident at the Chernobyl Atomic Electric Power Station].

The present study has been done in the framework of federal programme "Children of Chernobyl" with the aim to determine spread and structure of dental jaw abnormalities in children born and living in the radiation polluted regions after Chernobyl accident in 1986. 183 children have been examined in Donskoi town of Tula Province with the polluted soil by Cs-137 up to 5 Ci/km. All the examined children were divided into 2 groups: group 1--born in 1980-1986 and group 2--born in 1987-1994. It was determined that 76.5% of children have dental jaw system abnormalities. The most spread ones were occlusion abnormalities in combination with teeth abnormalities (28.9% cases) while the state of dental jaw system corresponding to the age standard was 2 times rarer in children born after the Chernobyl accident.

Abnormalities, Radiation-Induced↗