Thyroid cancer incidence among people living in areas contaminated by radiation from the Chernobyl accident

As a result of the Chernobyl nuclear power plant accident, massive amounts of radioactive materials were released into the environment and large numbers of individuals living in Belarus, Russia, and Ukraine were exposed to radioactive iodines, primarily 131I. Iodine-131 concentrated in the thyroid gland of residents of the contaminated areas, with children and adolescents being particularly affected. In the decade after the accident, a substantial increase in thyroid cancer incidence was observed among exposed children in the three affected countries, and compelling evidence of an association between pediatric thyroid cancer incidence and radiation exposure to the thyroid gland accumulated. The data currently available suggest that both the magnitude and patterns of thyroid cancer risk are generally consistent with those reported following external exposure. Based on data from case-control studies, iodine deficiency appeared to enhance the risk of developing thyroid cancer following exposure from Chernobyl. Results from a recent large cohort study, however, did not support these findings. Data on adult exposure are limited and not entirely consistent. Similarly, information on thyroid cancer risks associated with in utero exposure is insufficient to draw conclusions. The lack of information on these two population groups indicates an important gap that needs to be filled. Twenty years after the accident, excess thyroid cancers are still occurring among persons exposed as children or adolescents, and, if external radiation can be used as a guide, we can expect an excess of radiation-associated thyroid cancers for several more decades. Since considerable uncertainties about the long-term health effects from Chernobyl remain, continued follow-up of the exposed populations should provide valuable information.     

Cancer consequences of the Chernobyl accident: 20 years on.

26 April 2006 marks the 20th anniversary of the Chernobyl accident. On this occasion, the World Health Organization (WHO), within the UN Chernobyl Forum initiative, convened an Expert Group to evaluate the health impacts of Chernobyl. This paper summarises the findings relating to cancer. A dramatic increase in the incidence of thyroid cancer has been observed among those exposed to radioactive iodines in childhood and adolescence in the most contaminated territories. Iodine deficiency may have increased the risk of developing thyroid cancer following exposure to radioactive iodines, while prolonged stable iodine supplementation in the years after exposure may reduce this risk. Although increases in rates of other cancers have been reported, much of these increases appear to be due to other factors, including improvements in registration, reporting and diagnosis. Studies are few, however, and have methodological limitations. Further, because most radiation-related solid cancers continue to occur decades after exposure and because only 20 years have passed since the accident, it is too early to evaluate the full radiological impact of the accident. Apart from the large increase in thyroid cancer incidence in young people, there are at present no clearly demonstrated radiation-related increases in cancer risk. This should not, however, be interpreted to mean that no increase has in fact occurred: based on the experience of other populations exposed to ionising radiation, a small increase in the relative risk of cancer is expected, even at the low to moderate doses received. Although it is expected that epidemiological studies will have difficulty identifying such a risk, it may nevertheless translate into a substantial number of radiation-related cancer cases in the future, given the very large number of individuals exposed.     

Radiation and epidemiological analysis for solid cancer incidence among nuclear workers who participated in recovery operations following the accident at the Chernobyl NPP

This paper discusses the results of the analysis of the relationship between dose and solid cancer incidence among nuclear workers (males) who worked as liquidators after the Chernobyl accident. Information on this cohort of individuals is available at the regional center of Russian National Medical and Dosimetric Registry operating at the RF State Research Centre-Institute of Biophysics. Medical and dosimetric information on 8,654 persons 18-60 years of age with documented external radiation doses is used for the analysis. These data were gathered in the period from 1996 to 2001 and cover a total of 45,166.5 follow-up person-years. In the cohort under study, 179 solid cancers occurred during this period. The average age of liquidators at the time of exposure was 35.8 years, and the average dose as a result of the Chernobyl exposure was about 0.05 Sv. For an analysis of the dose-effect relationship (induction of radiation-induced malignant neoplasms) the statistical software EPICURE was used. The results of the analysis show that the cancer incidence in this cohort does not exceed cancer incidence in relevant age groups of the Russian population. The mean value of SIR for all cancer diseases was 0.88 (0.76, 1.02, 95% CI) for the whole period of follow-up. Risks for the induction of radiation-related cancer diseases were not statistically meaningful. Excess relative risk per 1 Sv was 0.95 (-1.52, 4.49, 95% CI).     

Third annual Warren K. Sinclair keynote address: retrospective analysis of impacts of the Chernobyl accident

The accident at the Chernobyl Nuclear Power Plant in 1986 was the most severe in the history of the nuclear industry, causing a huge release of radionuclides over large areas of Europe. The recently completed Chernobyl Forum concluded that after a number of years, along with reduction of radiation levels and accumulation of humanitarian consequences, severe social and economic depression of the affected regions and associated psychological problems of the general public and the workers had become the most significant problem to be addressed by the authorities. The majority of the >600,000 emergency and recovery operation workers and five million residents of the contaminated areas in Belarus, Russia, and Ukraine received relatively minor radiation doses which are comparable with the natural background levels. An exception is a cohort of several hundred emergency workers who received high radiation doses and of whom 28 persons died in 1986 due to acute radiation sickness. Apart from the dramatic increase in thyroid cancer incidence among those exposed to radioiodine at a young age and some increase of leukemia in the most exposed workers, there is no clearly demonstrated increase in the somatic diseases due to radiation. There was, however, an increase in psychological problems among the affected population, compounded by the social disruption that followed the break-up of the Soviet Union. Despite the unprecedented scale of the Chernobyl accident, its consequences on the health of people are far less severe than those of the atomic bombings of the cities of Hiroshima and Nagasaki. Studying the consequences of the Chernobyl accident has made an invaluable scientific contribution to the development of nuclear safety, radioecology, radiation medicine and protection, and also the social sciences. The Chernobyl accident initiated the global nuclear and radiation safety regime.     

Projecting the time trend of thyroid cancers: its impact on assessment of radiation-induced cancer risks

The incidence of thyroid cancer, which may be induced by ionizing radiation, has been rising in most Western countries for more than 20 years. In France, public worry about this increase and its possible connection with the fallout from Chernobyl led the government to ask for an evaluation of the health impact of this accident and an assessment of the feasibility of an epidemiological study. These requests raise two methodological questions: Which risk model should be used to relate exposure to risk? What is known about the spontaneous incidence rate of thyroid cancers? This article analyzes the impact of the time trend in the spontaneous incidence of thyroid cancers over the past 20 years in France when evaluating the risk of radiation-induced cancer. Age-period-cohort models were used to model the trend of spontaneous incidence from 1978 through 1997 and then to apply two scenarios for projections up to 2007: one with a constant incidence, the other using the trend observed over the past 20 years. Then the risk was assessed for a hypothetical population of 30,000 children aged 0 to 15 y, exposed to a hypothetical 0.1 Gy thyroid dose. The analysis shows that consideration of the trend instead of a constant spontaneous incidence can yield substantial differences in the risk estimates for thyroid cancer.     

Leukemia following the Chernobyl accident

The accident at the Chernobyl Nuclear Power Plant in Ukraine in 1986 led to a substantial increase of thyroid cancer among those exposed as children. The other cancer that is the most sensitive to the effects of ionizing radiation is leukemia, and this paper evaluates the evidence relating exposure to Chernobyl radioactivity and leukemia risk. Two types of objectives are identified, namely, scientific evidence and public health, and two approaches to addressing such objectives are discussed. Empirical studies in affected populations are summarized, and it is concluded that, possibly apart from Russian cleanup workers, no meaningful evidence of any statistical association between exposure and leukemia risk as yet exists. However, it is important to carry on with such studies to satisfy various public health objectives.     

Dynamics of thyroid cancer incidence in Russia following the Chernobyl accident.

This paper presents an analysis of thyroid cancer incidence in the territories of Russia most contaminated after the Chernobyl accident. In the work, data on incidence in the Bryansk, Kaluga, Orel and Tula regions (5298000 persons) are used. Altogether, 2599 cases of thyroid cancer are considered from 1982 to 1995. Of them, 143 cases were among the population who were children and adolescents at the time of the accident in 1986. The work uses the approach based on comparison of distributions of thyroid cancer cases by age at diagnosis and age at exposure. It has been shown that since 1991 the age structure of the incidence has changed significantly with a growing proportion of cases among children and adolescents. The change in the structure occurred due to the radiation factor, specifically as a result of exposure of thyroid to incorporated 131I. It has been shown that the standardised incidence ratio (SIR) of thyroid cancer among children who were 0-4 years at exposure in 1991-6 was 6 to 10 times higher than among adults. On the average, SIR for children and adolescents at the time of exposure is about three times higher than in adults.     

Thyroid cancer incidence in Chornobyl liquidators in Ukraine: SIR analysis, 1986–2010

We studied thyroid cancer incidence in a cohort of 150,813 male Chornobyl clean-up workers (“liquidators”) from Ukraine by calculating standardized incidence ratio (SIR) using national cancer statistics. Follow-up began on the liquidator’s registration date with the Chornobyl State Registry of Ukraine (the earliest date was 05. 05. 1986) and continued through December 31, 2010, date of thyroid cancer diagnosis, date of death, or date of last known vital status, whichever came first. There were 196 incident thyroid cancers in the study cohort with an overall SIR of 3.50 [95 % confidence interval (CI) 3.04–4.03]. A significantly elevated SIR estimate of 3.86 (95 % CI 3.26–4.57) was observed for liquidators who had their first clean-up mission in the Chornobyl zone in 1986, when levels of external and internal exposure to radiation were highest; the SIR estimates for later calendar years of first clean-up mission, while significantly elevated, were lower. The SIR estimates were elevated throughout the entire follow-up period but were especially high 10–18 years after the accident: 4.62 (95 % CI 3.47–6.15) and 4.80 (95 % CI 3.78–6.10) for the period 1995–1999 and 2000–2004, respectively. Our findings support the growing evidence of increased thyroid cancer rates among Chornobyl liquidators. Although this could be partially attributed to increased medical surveillance, the observed pattern of SIR increase warrants further investigation of a potential contribution of radiation exposure to the elevated thyroid cancer rates in this large population.     

Mental health consequences of the Chernobyl disaster

The psychosocial consequences of disasters have been studied for more than 100 years. The most common mental health consequences are depression, anxiety, post-traumatic stress disorder, medically unexplained somatic symptoms, and stigma. The excess morbidity rate of psychiatric disorders in the first year after a disaster is in the order of 20%. Disasters involving radiation are particularly pernicious because the exposure is invisible and universally dreaded, and can pose a long-term threat to health. After the Chernobyl disaster, studies of clean-up workers (liquidators) and adults from contaminated areas found a two-fold increase in post-traumatic stress and other mood and anxiety disorders and significantly poorer subjective ratings of health. Among liquidators, the most important risk factor was severity of exposure. In general population samples, the major risk factor was perceived exposure to harmful levels of radiation. These findings are consistent with results from A-bomb survivors and populations studied after the Three Mile Island nuclear power plant accident. With regard to children, apart from findings from ecological studies that lack direct data on radiation or other teratologic exposures and local studies in Kiev, the epidemiologic evidence suggests that neither radiation exposure nor the stress of growing up in the shadow of the accident was associated with emotional disorders, cognitive dysfunction, or impaired academic performance. Thus, based on the studies of adults, the Chernobyl Forum concluded that mental health was the largest public health problem unleashed by the accident. Since mental health is a leading cause of disability, physical morbidity, and mortality, health monitoring after radiation accidents like Fukushima should include standard measures of well-being. Moreover, given the comorbidity of mental and physical health, the findings support the value of training non-psychiatrist physicians in recognizing and treating common mental health problems like depression in Fukushima patients.     

Radiation-epidemiological analysis of incidence of non-cancer diseases among the Chernobyl liquidators

The work is concerned with assessment of radiation risks for non-cancer disease among the Chernobyl liquidators from 1986 to 1996. As of 1 January 1999, the Russian National Medical and Dosimetric Registry contains medical and dosimetric data for 174,000 liquidators. The cohort of 68,309 liquidators for whom best verified medical data are available is discussed. The dose dependency of incidence of non-cancer diseases was estimated by the cohort method and using the software package Epicure. For some classes of non-cancer diseases among liquidators, statistically significant estimates of radiation risk were derived for the first time. The highest excess relative risk per 1 Gy was found for cerebrovascular diseases; ERR Gy(-1)=1.17 at the 95% confidence interval (0.45; 1.88).     

Validity of thyroid cancer incidence data following the Chernobyl accident

The only clearly demonstrated cancer incidence increase that can be attributed to radiation from the Chernobyl accident is thyroid carcinoma in patients exposed during childhood or adolescence. Significant increases in thyroid disease were observed as soon as 4 y after the accident. The solid/follicular subtype of papillary carcinoma predominated in the early period after the accident. Morphological diagnosis of cancer in such cases, if no infiltrative growth is clearly visible, depends mainly on the nuclear criteria. Outdated equipment and insufficient quality of histological specimens impeded reliable evaluation of the nuclear criteria. Access to foreign professional literature has always been limited in the former Soviet Union. The great number of advanced tumors observed shortly after the accident can be explained by the screening effect (detection of previously neglected cancers) and by the fact that many patients were brought from non-contaminated areas and registered as Chernobyl victims. It is also worth noting that exaggeration of the Chernobyl cancer statistics facilitated the writing of dissertations, financing of research, and assistance from outside the former Soviet Union. "Chernobyl hysteria" impeded nuclear energy production in some countries, thus contributing to higher prices for fossil fuel. The concluding point is that since post-Chernobyl cancers tend on average to be in a later stage of tumor progression, some published data on molecular or immunohistochemical characteristics of Chernobyl-related cancers require reevaluation.     

Thyroid cancer among Ukrainians and Belarusians who were children or adolescents at the time of the Chernobyl accident.

Our objective is to assess the regional and temporal dependences of the baseline cases contributing to thyroid cancer incidence among those exposed in childhood or during adolescence in Belarus and Ukraine after the Chernobyl accident. Data are analysed for Kyiv and Sevastopol City and the 25 oblasts (regions) in Ukraine, and for Minsk and Gomel City and the 6 oblasts in Belarus. Average thyroid doses due to the Chernobyl accident were assessed for every birth year in the period from 1968 to 1985. Case data pertain to people who underwent surgical removal of thyroid cancers during the period 1986 to 2001 and who were allocated to their place of residence at the time of the accident. The 35 oblasts/cities were subdivided into an upper, middle and lower group of baseline thyroid cancer incidence. Poisson regressions were performed to estimate age, time and gender dependences of the baseline incidence rates in the three groups. The majority of oblasts/cities with high average doses and the majority of Belarusian oblasts/cities belong to the upper group of baseline thyroid cancer incidence. The baseline in the upper group is estimated to be larger than in the middle group by a factor of 2.3, and by a factor of 4.0 when compared to the lower group. The baseline incidence increases with age and with time since exposure. Estimated baseline incidence rates were found to increase from 1988 to 1999 by factors of three and two for the upper and the two lower groups respectively. The estimated thyroid cancer incidence rates in Belarus and Ukraine, and their dependences on gender and age, are consistent with observed rates found in the larger cancer registries of other countries. In conclusion, the baseline cases are found to contribute about 70% to the thyroid cancer incidence in Ukraine, and about 40% to the incidence in Belarus.     

Patterns of acute leukaemia occurrence among children in the Chernobyl region

BACKGROUND: The Chernobyl nuclear accident of 1986 released large quantities of radioactive material causing widespread contamination. In the Ukraine alone, more than 4 million people were exposed to radiation. The exact health consequences of this exposure are still being assessed. METHODS: To ascertain the effect of in utero radiation exposure and the development of leukaemia, a review was undertaken of leukaemia sub-types occurring among children born in the year of the accident (1986) and followed 10 years post-exposure. A comparison was made of leukaemia cumulative incidence rates among children from both an exposed and unexposed oblast. RESULTS: Rate ratios (RR) for the all cell types grouping of leukaemia revealed that rates in the exposed Oblast were significantly elevated for females, males and both genders combined. Rates of acute lymphoblastic leukaemia (ALL) were dramatically elevated for males and to a lesser extent for females. For both genders combined, the RR for ALL was more than three times greater in the exposed compared to the unexposed region. CONCLUSION: Study results suggest that the increased risk of leukaemia and acute leukaemia among those children born in 1986 and resident in radioactively contaminated territories may be associated with exposure to radiation resulting from the Chernobyl accident.     

The Chernobyl accident 20 years on: an assessment of the health consequences and the international response

Twenty years after the Chernobyl accident the WHO and the International Atomic Energy Authority issued a reassuring statement about the consequences. Our objectives in this study were to evaluate the health impact of the Chernobyl accident, assess the international response to the accident, and consider how to improve responses to future accidents. So far, radiation to the thyroid from radioisotopes of iodine has caused several thousand cases of thyroid cancer but very few deaths; exposed children were most susceptible. The focus on thyroid cancer has diverted attention from possible nonthyroid effects. The international response to the accident was inadequate and uncoordinated, and has been unjustifiably reassuring. Accurate assessment in future health effects is not currently possible in the light of dose uncertainties, current debates over radiation actions, and the lessons from the late consequences of atomic bomb exposure. Because of the uncertainties from and the consequences of the accident, it is essential that investigations of its effects should be broadened and supported for the long term. The United Nations should initiate an independent review of the actions and assignments of the agencies concerned, with recommendations for dealing with future international-scale accidents. These should involve independent scientists and ensure cooperation rather than rivalry.     

A cohort study of thyroid cancer and other thyroid diseases after the Chornobyl accident: dose-response analysis of thyroid follicular adenomas detected during first screening in Ukraine (1998-2000)

The Chornobyl (Chernobyl) accident in 1986 exposed many individuals to radioactive iodines, chiefly (131)I, the effects of which on benign thyroid diseases are largely unknown. To investigate the risk of follicular adenoma in relation to radiation dose after Chornobyl, the authors analyzed the baseline data from a prospective screening cohort study of those exposed as children or adolescents. A stratified random sample was selected from all individuals who were younger than 18 years, had thyroid radioactivity measurements taken within 2 months after the accident, and resided in the three heavily contaminated areas in Ukraine. This analysis is based on the 23 cases diagnosed in 12,504 subjects for whom personal history of thyroid diseases was known. The dose-response relation was linear with an excess relative risk of 2.07 per gray (95% confidence interval: 0.28, 10.31). The risk was significantly higher in women compared with men, with no clear modifying effects of age at exposure. In conclusion, persons exposed to radioactive iodines as children and adolescents have an increased risk of follicular adenoma, though it is smaller than the risk of thyroid cancer in the same cohort. Compared with results from other studies, this estimate is somewhat smaller, but confidence intervals overlap, suggesting compatibility.     

Iodine deficiency,radiation dose,and the risk of thyroid cancer among children and adolescents in the Bryansk region of Russia following the Chernobyl power station accident

BACKGROUND: Little is known about the joint effect of iodine deficiency and radiation exposure on the risk of thyroid cancer. No epidemiological studies have been published assessing the modifying effect of iodine deficiency on radiation-induced thyroid cancer following the Chernobyl accident. METHODS: A population sample of 3070 individuals (2590 ages 6-18, and 480 adults) from 75 settlements in the most highly contaminated regions of the Bryansk Oblast of Russia was identified and sampled for urinary iodine measurements in 1996, and iodine deficiency in each geopolitical unit (raion) was estimated. All cases of thyroid cancer were identified in those born 1968-1986 who were resident in the study area in May-June 1986 (34 histologically confirmed cases). The risk of thyroid cancer was examined in relation to population estimates of thyroid radiation dose and urinary iodine excretion level. RESULTS: The excess relative risk (ERR) of thyroid cancer was significantly associated with increasing thyroid radiation dose, and was inversely associated with urinary iodine excretion levels. There was a joint effect of radiation exposure and iodine deficiency. At 1 gray (Gy), the ERR in territories with severe iodine deficiency was approximately two times that in areas of normal iodine intake. CONCLUSIONS: These findings suggest that elimination of iodine deficiency in areas affected by Chernobyl may be important in reducing the effects of radiation exposure on the thyroid. If confirmed by studies based on individuals, they may have implications for the use of stable iodine in the case of population exposure to radioactive iodine.     

Radiation epidemiology: a perspective on Fukushima

For nearly 100 years, epidemiologic studies of human populations exposed to ionising radiation have provided quantitative information on health risks. High dose deterministic (tissue reaction) effects result when sufficient numbers of functioning cells are killed, such as in bone marrow depression that can lead to death. Lower dose stochastic effects are probabilistic in nature and include an increased risk of cancer later in life and heritable genetic defects, although genetic conditions in the children of irradiated parents have yet to be convincingly demonstrated. Radiation studies are of diverse populations and include not only the Japanese atomic bomb survivors, but also patients treated with radiation for malignant and non-malignant disease; patients exposed for diagnostic purposes; persons with intakes of radionuclides; workers occupationally exposed; and communities exposed to environmental and accidentally released sources of radiation. Much is known about radiation and its risks. The major unanswered question in radiation epidemiology, however, is not whether radiation causes cancer, but what the level of risk is following low dose (<100 mSv) or low dose rate exposures. Paracelsus is credited with first articulating that the 'poison is in the dose', which for radiation epidemiology translates as 'the lower the dose, the lower the risk' and, an important corollary, the lower the dose, the greater the difficulty in detecting any increase in the number of cancers possibly attributable to radiation. In contrast to the Chernobyl reactor accident, the Fukushima reactor accident has to date resulted in no deterministic effects and no worker deaths. Estimates to date of population doses suggest very low uptakes of radioactive iodine which was a major determinant of the epidemic of thyroid cancer following childhood exposures around Chernobyl. The estimates to date of population doses are also much lower (and the distribution much narrower) than the doses for which cancer excesses have been detected among atomic bomb survivors after 60 years of follow-up. Studies of populations exposed to low doses are also limited in their ability to account for important lifestyle factors, such as cigarette smoking and medical x-ray exposures, which could distort findings. Studies of the Fukushima population should be and are being considered for reassurance and health care reasons. Apart from as regards the extreme psychological stress caused by the horrific loss of life following the tsunami and the large-scale evacuation from homes and villages, such studies have limited to no chance of providing information on possible health risks following low dose exposures received gradually over time--the estimated doses (to date) are just too small.     

The chernobyl accident 20 years on: an assessment of the health consequences and the international response

BACKGROUND: The Chernobyl accident in 1986 caused widespread radioactive contamination and enormous concern. Twenty years later, the World Health Organization and the International Atomic Energy Authority issued a generally reassuring statement about the consequences. Accurate assessment of the consequences is important to the current debate on nuclear power. OBJECTIVES: Our objectives in this study were to evaluate the health impact of the Chernobyl accident, assess the international response to the accident, and consider how to improve responses to future accidents. DISCUSSION: So far, radiation to the thyroid from radioisotopes of iodine has caused several thousand cases of thyroid cancer but very few deaths ; exposed children were most susceptible. The focus on thyroid cancer has diverted attention from possible nonthyroid effects, such as mini-satellite instability, which is potentially important. The international response to the accident was inadequate and uncoordinated, and has been unjustifiably reassuring. Accurate assessment of Chernobyl's future health effects is not currently possible in the light of dose uncertainties, current debates over radiation actions, and the lessons from the late consequences of atomic bomb exposure. CONCLUSIONS: Because of the uncertainties over the dose from and the consequences of the Chernobyl accident, it is essential that investigations of its effects should be broadened and supported for the long term. Because of the problems with the international response to Chernobyl, the United Nations should initiate an independent review of the actions and assignments of the agencies concerned, with recommendations for dealing with future international-scale accidents. These should involve independent scientists and ensure cooperation rather than rivalry.     

Somatic health effects of Chernobyl: 30 years on

2016 marked the 30th anniversary of the Chernobyl Nuclear Power Plant accident. We and others wrote reviews for the 25th anniversary. Since then, additional papers have appeared and it seems timely to highlight lessons learned. To present, not a systematic review, but a commentary drawing attention to notable findings. We include not only recent reports and updates on previous results, but key findings from prior Chernobyl studies. The dose-dependent increase in Papillary Thyroid Cancer (PTC) following childhood I-131 exposure in Ukraine and Belarus has now been shown to persist for decades. Studies of post-Chernobyl PTCs have produced novel information on chromosomal rearrangements and gene fusions, critical to understanding molecular mechanisms. Studies of clean-up workers/liquidators suggest dose-related increases of thyroid cancer and hematological malignancies in adults. They also report increases in cardiovascular and cerebrovascular disease. If confirmed, these would have significant public health and radiation protection implications. The lens opacities following low to moderate doses found earlier are also a concern, particularly among interventional radiologists who may receive substantial lens doses. Finally, there is some, inconsistent, evidence for genetic effects among offspring of exposed persons. Further efforts, including improved dosimetry, collection of information on other risk factors, and continued follow-up/monitoring of established cohorts, could contribute importantly to further understand effects of low doses and dose-rates of radiation, particularly in young people, and ensure that appropriate public health and radiation protection systems are in place. This will require multinational collaborations and long-term funding.     

Health effects from fallout

This paper primarily discusses health effects that have resulted from exposures received as a result of above-ground nuclear tests, with emphasis on thyroid disease from exposure to 131I and leukemia and solid cancers from low dose rate external and internal exposure. Results of epidemiological studies of fallout exposures in the Marshall Islands and from the Nevada Test Site are summarized, and studies of persons with exposures similar to those from fallout are briefly reviewed (including patients exposed to 131I for medical reasons and workers exposed externally at low doses and low dose rates). Promising new studies of populations exposed in countries of the former Soviet Union are also discussed and include persons living near the Semipalatinsk Test Site in Kazakhstan, persons exposed as a result of the Chernobyl accident, and persons exposed as a result of operations of the Mayak Nuclear Plant in the Russian Federation. Very preliminary estimates of cancer risks from fallout doses received by the United States population are presented.