Clean-up Workers Research Articles

Метод оценки радиационных рисков смертности ликвидаторов чернобыльской аварии, учитывающий возможные ошибки в постановке и регистрации диагнозов причин смерти

In the past decade the lawful use of radiation risks of non-cancer diseases estimates to solve ra-diation safety problems has become more significant. The highest statistical power of low dose (less than 0.2 Gy) radiation risks research is possible in the cohort of the Chernobyl clean-up workers (liquidators) registered and been under medical monitoring in the system of the National Radiation Epidemiological Register (NRER) since 1986. The liquidators total number exceeds 130 thousand people. Because of the large-scale annual collection of health data, carried out in the NRER system, verification of the diseases diagnoses and medically certified causes of death, a natural question of radiation risk estimates compatibility with consideration to probable errors in a disease diagnosis and cause-of-death reporting on death certificates arises. The work is aimed at estimating the radiation risk of mortality from diseases of the circulatory system and diseases of the digestive organs in the Russian cohort of liquidators, with account of possible errors in the disease diagnosis and certified causes of death. The size of the cohort considered for mortality analysis was 91,013 people, the average age at the Chernobyl zone entry was 33.6 years, average radiation dose was 0.133 Gy. In this study, the method of maximizing the partial likelihood function was used to assess radiation risks, with consideration of individual radiation doses to liquidators and the assessment of background mortality using the Breslow method. The specificity of the diagnosis of the primary causes of death in the NRER system significantly exceeds the level of 0.99. Considering the specificity index of 0.99, the estimates of radiation risk coefficients ERR/Gy for mortality from diseases of the circulatory system and diseases of the digestive system in the cohort of Russian liquidators do not differ from the estimates obtained in the assumption that there are no first kind errors (false positive diagnosis) in the diagnoses of the primary causes of death in the NRER database. The results obtained confirm the high stability and validity of the assessments of radiation risks of mortality from diseases of the circulatory system and diseases of the digestive system, obtained earlier from the data on liquidators registered in the NRER.

COMORBID PATHOLOGY IN FATAL CASES DUE TO CORONAVIRUS DISEASE (COVID-19) IN VICTIMS OF THE CHORNOBYL NPP ACCIDENT.

The victims of the Chornobyl accident, as well as whole population of Ukraine, have become the object of the COVID-19 pandemic in today's conditions. As of 01.01.2020, 108,898 victims had documented permanent disability (persons with disabilities) and, as a rule, suffered from 4-6 types of non-tumor chronic diseases of internal organs, primarily the circulatory system, as well as oncological and endocrine pathology, that significantly affect the course of COVID-19 in a severe scenario and contribute to death. This determines the relevance of the issue of the impact of comorbid pathology in fatal cases due to coronavirus disease (COVID-19) in victims of the Chornobyl accident.The Objective of the study was to study the nature and significance of comorbid pathology in the victims of the Chernobyl accident who died from COVID-19.Design, object and methods of the study - a retrospective non-randomized, comparative comprehensive analysis of the materials of 134 medical expert cases of male clean-up workers of the Chornobyl accident who died from COVID-19 in 2020-2022 during the pandemic was carried out. The analysis of the materials of expert cases included the study of clinically significant and morphologically confirmed pathological processes. The source of the data was the materials of the Central Interdepartmental Expert Commission of the Ministry of Health of Ukraine on the establishment of causal relationship of diseases, disability and death with the action of ionizing radiation and other harmful factors as a result of the Chernobyl accident. In the structure of comorbid pathology in the clean-up workers of the Chornobyl accident who died due to COVID-19 during 2020-2022, diseases of the circulatory system dominate, which occurred in 86.57% of cases of consideration of medical expert cases. AH complicated the course and contributed to the development of fatal consequences in 52.24% of cases, ChIHD - in 34.32% of cases. The consequences of acute vascular events in the form of post-infarction cardiosclerosis in patients with ChIHD contributed to death in COVID-19 in 29 (21.64%) cases.Cerebrovascular pathology represented by cerebral atherosclerosis was detected in 76 (56.72%) cases of death from COVID-19. Acute vascular cerebral events in the cerebral basin (ischemic and hemorrhagic strokes) contributed to fatal outcomes in 19 (14.18%) cases. The presence and course of diabetes mellitus also had a significant impact on the course and fatal mortality of COVID-19 - 24.63% (33 cases). Chronic respiratory diseases (COPD) influenced the course of COVID-19 and contributed to death in 6.72% (9) of cases, nephrological pathology (ChTIN) - in 2.98% (4) of cases, peptic ulcer disease of the duedenum - in 2.24% (3) of cases. More than half of the clean-up workers of the Chornobyl NPP accident who died due to COVID-19 had more than two severe chronic diseases of the comorbid component and their complications. Сlean-up workers of the Chornobyl accident who died from COVID-19 had another severe comorbid chronic disease, or several diseases that influenced the course of coronavirus disease and each other and contributed to the development of fatal consequences. Death from COVID-19 is much more common in clean-up workers of the Chornobyl accident suffering from severe disabling non-oncological diseases of the cardiovascular system (arterial hypertension, coronary heart disease), cerebrovascular diseases with consequences of acute vascular events, as well as diabetes mellitus. Victims of the Chornobyl catastrophe, especially clean-up workers of the Chornobyl NPP accident, are at special risk for severe coronavirus disease and death from COVID-19.

THE COURSE OF CHRONIC LYMPHOCYTIC LEUKEMIA AFTER SARS-COV-2 VIRUS INFECTION.

Objective - to investigate the course of B-cell chronic lymphocytic leukemia (CLL) in patients after SARS-CoV-2 virus infection taking into account anamnestic exposure to the ionizing radiation (IR).Methods. The study was performed in a group of 51 CLL patients who were admitted to the Department of Radiation hematology of the National Research Center for Radiation Medicine of NAMS of Ukraine, Kyiv, from January 2020 (the beginning of SARS-CoV-2 epidemic) to August 2023. The group included 19 (37.3 %) clean-up workers of the Chornobyl NPP accident, 15 (29.4 %) inhabitants of radionuclide contaminated areas and 17 (33.3 %) IR non-exposed patients. The diagnosis of CLL was based on clinical history, lymphocyte morphology, and immunophenotypic criteria. Statistical studies were performed using the SPSS software package, version 20.0.Results. The diagnosis of CLL was established for the first time in 14 patients, in seven of them, CLL was diagnosed after 2-17 months after SARS-CoV-2 infection. In contrast to patients who did not suffer from a coronavirus infection, they had pronounced lymphadenopathy, which in some cases was accompanied by hyperleukocytosis, and needed early treatment. Thirteen patients with a previously established CLL were diagnosed with COVID-19 by PCR test. In seven of them (53.8 %) starting treatment was needed, or CLL has progressed. Seven of 51 patients (13.5 %) were vaccinated against SARS-CoV-2. Then, four of them were diagnosed with SARS-CoV-2 infection, confirmed by a positive PCR test, and two patients had a relapse of CLL within 1-2 months after vaccination. Most of patients with signs of the influence of SARS-CoV-2 infection on CLL belonged to sufferers of the Chornobyl NPP accident Conclusions. The clinical features of CLL that developed after SARS-CoV-2 were characterized firstly. The negative impact of SARS-CoV-2 infection on previously established CLL was established. The question about vaccination of CLL patients remains debatable.

STATUS OF THE CELLULAR IMMUNITY IN CLEAN-UP WORKERS OF THE CHORNOBYL ACCIDENT AND PATIENTS WITH CANCER OF THE MOUTH CAVITY, ORAL AND LARYNGEAL PART OF THE PHARYNX.

to establish cellular immunity in clean-up workers of the Chornobyl accident compared to patients with malignant neoplasms of the oral cavity, oral and laryngeal parts of the pharynx according to the subpopulation organization of peripheral blood leukocytes. We examined 112 males, age (56,92 ± 6,17) years (M ± SD), including 26 male clean-up workers exposed at the radiation dose 10-500 mSv; 20 male clean-up workers exposed at the dose range 504-990mSv; 33 patients with malignant neoplasms of the oral cavity, oral and laryngeal parts of the pharynx and 33 non-exposed subjects of the control group. Immune cell subsets analysis was performed by the expression of differential and activation antigens of peripheral blood leukocytes using flow cytometry. In assessing each group's cellular immunity, there was a decrease in the number of CD19+ B-lymphocytes, CD3+ HLA-DR+ T- and CD3- HLA-DR+ B-lymphocytes, CD3- 16+ 56+ natural killer cells, combined with an increase in the number of CD8+ T-lymphocytes. An increase in the relative number of CD4+ CD8+ T-lymphocytes was determined in clean-up workers (D < 500 mSv) and cancer patients. An increase in the number of CD8+ T-lymphocytes and a decrease in the number of CD4+ T-lymphocytes were observed in clean-up workers (D > 500 mSv), as well as in cancer patients. In addition, a decrease of monocytes, CD3+ 16+ 56+ , and CD3+ TCRαβ+ T-lymphocytes was determined in patients with oncological pathology. The obtained results show the unidirectionality of changes in cellular immunity in the participants of the liquidation of the consequences of the accident at the Chornobyl nuclear power plant and patients with the investigated oncological pathology, which indicates the formation of persistent violations of antitumor protection in the participants of the liquidation of the consequences of the accident as the basis of oncogenesis. Determining changes in the number of lymphocytes, monocytes, granulocytes, CD4+ T-lymphocytes, CD4+ CD8+ immature T-lymphocytes, the immunoregulatory ratio CD4+ / CD8+, CD3+TCRαβ+ T-lymphocytes and CD3+ 16+ 56+ CTL can have an additional effect on the effectiveness antitumor protection and the probability of oncogenesis risk in immunocompromised individuals.

Associations between BTEX-H/THC and neurological symptoms among Deepwater Horizon oil spill workers

Background and Aim Hydrocarbons are considered to be neurotoxic. However, less is known about health effects of generally lower exposures during oil spill response and clean-up. The Gulf Long-Term Follow-up (GuLF) Study follows individuals who were either involved in cleanup efforts (&amp;#x22;workers”) or were trained but not hired (&amp;#x22;non-workers”) following the 2010 Deepwater Horizon disaster. We studied the association of neurological symptoms with exposure to benzene, toluene, ethylbenzene, xylenes, and hexane (BTEX-H) individually and as a mixture among 23,641 workers. Methods At enrollment, participants self-reported frequency of neurological symptoms including dizziness, nausea, sweating, heart palpitations, fatigue, insomnia, migraines, tingling, numbness, blurred vision, stumbling, and seizures in the preceding 30 days. Cumulative inhalation exposure to BTEX-H chemicals and total hydrocarbons (THC) was estimated using a job exposure matrix linking air measurement data to detailed self-reported cleanup work histories. We calculated adjusted prevalence ratios (PR) and 95% confidence intervals (CI) for the association between quartiles of exposure and neurological symptoms reported all or most of the time using multivariable log-binomial regression. Quantile G-computation was used to estimate the per-quartile increase in joint effects of the BTEX-H mixture on neurological symptoms. Results 31% of participants reported experiencing at least one, and 21% reported 2 or more, neurological symptoms within the last 30 days. Exposure to THC was associated with increased risk of two or more neurological symptoms (Q4 vs. Q1 PR=1.57 (95% CI:1.45, 1.70)), with similar results observed for the individual BTEX-H chemicals. A quartile increase in exposure to the BTEX-H mixture was associated with an increased risk of reporting two or more neurological symptoms (PR=1.18, (95% CI: 1.15, 1.21)). Conclusions Exposure to oil spill-related THC and BTEX-H was associated with increased prevalence of neurological symptoms among cleanup workers. Keywords: Occupational epidemiology, crude oil, BTEX, neurological symptoms, disaster

Associations between airborne crude oil chemicals and symptom-based asthma.

The 2010 Deepwater Horizon (DWH) oil spill response and cleanup (OSRC) workers were exposed to airborne total hydrocarbons (THC), benzene, toluene, ethylbenzene, o-, m-, and p-xylenes and n-hexane (BTEX-H) from crude oil and PM2.5 from burning/flaring oil and natural gas. Little is known about asthma risk among oil spill cleanup workers. We assessed the relationship between asthma and several oil spill-related exposures including job classes, THC, individual BTEX-H chemicals, the BTEX-H mixture, and PM2.5 using data from the Gulf Long-Term Follow-up (GuLF) Study, a prospective cohort of 24,937 cleanup workers and 7,671 nonworkers following the DWH disaster. Our analysis largely focused on the 19,018 workers without asthma before the spill who had complete exposure, outcome, and covariate information. We defined incident asthma 1-3years following exposure using both self-reported wheeze and self-reported physician diagnosis of asthma. THC and BTEX-H were assigned to participants based on measurement data and work histories, while PM2.5 used modeled estimates. We used modified Poisson regression to estimate risk ratios (RR) and 95% confidence intervals (CIs) for associations between spill-related exposures and asthma and a quantile-based g-computation approach to explore the joint effect of the BTEX-H mixture on asthma risk. OSRC workers had greater asthma risk than nonworkers (RR: 1.60, 95% CI: 1.38, 1.85). Higher estimated THC exposure levels were associated with increased risk in an exposure-dependent manner (linear trend test p<0.0001). Asthma risk also increased with increasing exposure to individual BTEX-H chemicals and the chemical mixture: A simultaneous quartile increase in the BTEX-H mixture was associated with an increased asthma risk of 1.45 (95% CI: 1.35,1.55). With fewer cases, associations were less apparent for physician-diagnosed asthma alone. THC and BTEX-H were associated with increased asthma risk defined using wheeze symptoms as well as a physician diagnosis.

Biological effects of inhaled crude oil vapor V. Altered biogenic amine neurotransmitters and neural protein expression

Workers in the oil and gas industry are at risk for exposure to a number of physical and chemical hazards at the workplace. Chemical hazard risks include inhalation of crude oil or its volatile components. While several studies have investigated the neurotoxic effects of volatile hydrocarbons, in general, there is a paucity of studies assessing the neurotoxicity of crude oil vapor (COV). Consequent to the 2010 Deepwater Horizon (DWH) oil spill, there is growing concern about the short- and long-term health effects of exposure to COV. NIOSH surveys suggested that the DWH oil spill cleanup workers experienced neurological symptoms, including depression and mood disorders, but the health effects apart from oil dispersants were difficult to discern. To investigate the potential neurological risks of COV, male Sprague-Dawley rats were exposed by whole-body inhalation to COV (300 ppm; Macondo surrogate crude oil) following an acute (6 h/d × 1 d) or sub-chronic (6 h/d × 4 d/wk. × 4 wks) exposure regimen. At 1, 28 or 90 d post-exposure, norepinephrine (NE), epinephrine (EPI), dopamine (DA) and serotonin (5-HT) were evaluated as neurotransmitter imbalances are associated with psychosocial-, motor- and cognitive- disorders. Sub-chronic COV exposure caused significant reductions in NE, EPI and DA in the dopaminergic brain regions, striatum (STR) and midbrain (MB), and a large increase in 5-HT in the STR. Further, sub-chronic exposure to COV caused upregulation of synaptic and Parkinson's disease-related proteins in the STR and MB. Whether such effects will lead to neurodegenerative outcomes remain to be investigated.

Захворюваність на злоякісні новоутворення населення України у віддаленому періоді після аварії на ЧАЕС

There is performed a study of cancer incidence in the population affected by the Chornobyl accident. Analysis of demography situation has shown that unlike Western European countries with increasing life expectancy this index was notably decreased in Ukraine in 2005–2006 with slow growth during 2006–2019. Certainly this circumstance may influence on cancer incidence rate because the highest risk of malignant tumours is just in elderly age. Goal: to determine the frequency and risk of malignant neoplasms in groups of the population of Ukraine that were exposed to radiation as a result of the Chоrnobyl accident in the remote post-accident period. Materials and methods. The study was conducted on the basis of long-term monitoring of malignant tumours in the groups of victims – clean-up workers of 1986–1987, evacuees from the exclusion zone, residents of the territories most heavily contaminated with radionuclides. Results. There was a significant excess of the expected level of incidence of thyroid cancer among the participants in liquidation of the accident consequences (PLAC) - 4.5 times, evacuees - 3.8 times, residents of territories contaminated with radionuclides - 1.3 times. Leukaemia and lymphoma incidence rate in residents of contaminated territories increased sharply in the first years after the accident but decreased in the next years and not exceeded the level if Kyiv and Zhytomyr regions and Ukraine at whole. In a joint Ukrainian-American analytical epidemiological case-control study dose dependent excess relative risk of leukaemia (ERR/Gy) was proved in clean-up workers and defined at level 2.38 (0.49–5.87) in 1986–2006. A significant excess of the national level of incidence of breast cancer was determined only in women - PLAC in 1986–1987. In 1994–2019 SIR was 156.3% (95% CI: 141.0–171.5). Conclusions. Because latency period for different forms of radiation related malignancies might be very long further special attention should be paid not only to nosological forms mentioned above but also to cancers of the other sites.

The association between oil spill cleanup-related total hydrocarbon exposure and diabetes

BackgroundAlthough evidence suggests relationships between some crude oil components and glycemic dysregulation, no studies have examined oil spill-related chemical exposures in relation to type 2 diabetes mellitus (DM) risk. This study examined the relationship between total hydrocarbon (THC) exposure among workers involved in the 2010 Deepwater Horizon (DWH) oil spill and risk of DM up to 6 years afterward. MethodsParticipants comprised 2660 oil-spill cleanup or response workers in the prospective GuLF Study who completed a clinical exam and had no self-reported DM diagnosis prior to the spill. Maximum THC exposure was estimated with a job-exposure matrix based on interview data and personal measurements taken during cleanup operations. We defined incident DM by self-reported physician diagnosis of DM, antidiabetic medication use, or a measured hemoglobin A1c value ≥ 6.5%. We used log binomial regression to estimate risk ratios (RRs) for DM across ordinal categories of THC exposure. The fully adjusted model controlled for age, sex, race/ethnicity, education, employment status, and health insurance status. We also stratified on clinical body mass index categories. ResultsWe observed an exposure-response relationship between maximum daily ordinal THC exposure level and incident DM, especially among overweight participants. RRs among overweight participants were 0.99 (95% CI: 0.37, 2.69), 1.46 (95% CI: 0.54, 3.92), and 2.11 (95% CI: 0.78, 5.74) for exposure categories 0.30–0.99 ppm, 1.00–2.99 ppm, and ≥3.00 ppm, respectively (ptrend = 0.03). ConclusionWe observed suggestively increasing DM risk with increasing THC exposure level among overweight participants, but not among normal weight or obese participants.

Aging and mental health of the Chornobyl catastrophe survivors

IntroductionThe Chornobyl catastrophe (ChC) has impacted on depopulation and mental health of the survivors, however, the rate of demographic aging and mental health survey remain at issue.ObjectivesTo determine the rate of demographic aging of ChC survivors and to analyze the state of their mental health survey.MethodsInformation from the Ministry of Health and the State Statistics Service of Ukraine, Clinical and Epidemiological Register, the State Register of ChC survivors, and clinical neuropsychiatric data were analyzed.ResultsIn 2018, compared to 1995, the number of the ChC survivors decreased by 987 thousand with high level of aging: ChC clean-up workers – 59.0%; evacuees – 25.0%, and residents of radioactively contaminated territories (RCT) – 30.7%. There are negative tendencies in age parameters of survival of the RCT population. Long-term mental health disorders and neuropsychiatric effects in the ChC survivors have been identified, which may indicate an accelerated aging. Neurophysiological and molecular-biological atypia of aging processes under an exposure to low doses of and low dose rate of ionizing radiation have been found. Existing statistical and registry data underestimate the level of mental disorders in the population of Ukraine, including the ChC survivors by an order of magnitude.ConclusionsThe negative tendencies in age parameters of survival indicate the need to continue research to identify the factors “responsible” for such changes. Mental health disorders and neuropsychiatric effects in the ChC survivors are underestimated. It is necessary to create a national psychiatric registry of Ukraine and long-term (lifelong) monitoring of survivors.DisclosureNo significant relationships.

Schizophrenia spectrum disorders following past exposure to ionizing radiation and SARS CoV-2 infection

IntroductionWhether exist a potential association between schizophrenia spectrum disorders following past exposure to ionizing radiation and SARS CoV-2 infection is unknown.ObjectivesTo assess a possible role of double radiation-viral exposure in pre- and postnatal periods in schizophrenia spectrum disorders genesis.MethodsIntegration and analysis of information available with the results of own clinical and epidemiological studies.ResultsThe renaissance of interest to the viral hypothesis of schizophrenia is observing during the current COVID-19 pandemic. There is an increasing number of cases and case series reports on psychotic schizophreniform disorders following SARS CoV-2 infection diagnosed as COVID-19-asssociated brief psychotic disorder, first episode psychosis, acute and transient psychotic disorder. The prevalence rate of schizophrenia in A-bomb survivors in Nagasaki was very high – 6 % (Nakane and Ohta, 1986), and increased in those prenatally exposed to A-bombing (Imamura et al., 1995) and medical X-irradiation (Gross et al., 2018). We found a significant increase in the schizophrenia incidence in the Chornobyl exclusion zone personnel, as well as schizophreniform syndromes in Chornobyl clean-up workers (liquidators) irradiated by moderate to high doses (more than 0.30 Sv). The neural diathesis-stressor hypothesis of schizophrenia spectrum disorders was proposed (Loganovsky and Loganovskaja, 2000; Loganovsky et al., 2005). Recently we observed the clinical case of organic schizophrenia-like disorder in the liquidator who was ill with COVID-19.ConclusionsThe linkage between schizophrenia spectrum disorders following past exposure to ionizing radiation and SARS CoV-2 infection can exist that should be studied on the irradiated cohorts with following COVID-19.DisclosureNo significant relationships.

Radiation-associated cerebroophtalmic effects

IntroductionWe proposed to consider the brain and eye as a target of ionizing radiation exposure. Prevention of potential radiation-associated cerebroophtalmic effects are crucial for successful long-term space missions; interventional radiology; medical, occupational and accidental irradiationObjectivesDetermination of radiation-associated cerebroophtalmic effects in the long term after irradiation in adulthood and in utero.MethodsNeuropsychiatric, ophtalmological, neurophysiological and neuropsychological assessment of irradiated in adulthood (57 Chernobyl accident clean-up workers, liquidators), 52 persons exposed in utero as a result of the Chernobyl accident, comparison group (51 combatants of the Antiterrorist operation in Donbass), and 53 healthy people.ResultsRadiation-associated cerebroophthalmic pathology is characterized by high neuropsychiatric and ophthalmic comorbidity, which increases in proportion to the radiation dose, and is mainly represented by chronic vascular and degenerative diseases of the brain and retina, mild cognitive impairment (after irradiation in adulthood), as well as disorders of the autonomic nervous system; non-psychotic organic mental disorders; neurotic, stress-related and somatoform disorders; vascular and dystrophic processes in the retina (after in utero exposure). Characteristic of both radiological scenarios remains intellectual disharmony due to a decrease in the verbal IQ. The delay and attenuation of cerebral visual afferentation processing were observed in prenatally exposed.ConclusionsRadiation-associated cerebroophtalmic effects in the long term after irradiation in adulthood and in utero could be mainly classified as a “small vessel disease of the brain and eye” of vascular-degenerative nature and possible latent demyelination after irradiation in utero.DisclosureNo significant relationships.

Reliability of Questionnaire-Based Dose Reconstruction: Human Factor Uncertainties in the Radiation Dosimetry of Chernobyl Cleanup Workers.

This original study aims to quantify the human factor uncertainties in radiation doses for Chernobyl cleanup workers that are associated with errors in direct or proxy personal interviews due to poor memory recall a long time after exposure. Two types of doses due to external irradiation during cleanup mission were calculated independently. First, a "reference" dose, that was calculated using the historical description of cleanup activities reported by 47 cleanup workers shortly after the completion of the cleanup mission. Second, a "current" dose that was calculated using information reported by 47 cleanup workers and respective 24 proxies (colleagues) nominated by cleanup workers during a personal interview conducted more recently, as part of this study, i.e., 25-30 years after their cleanup missions. The Jaccard similarity coefficient for reference and current doses was moderate: the arithmetic mean ± standard deviation was 0.29 ± 0.18 (median = 0.31) and 0.23 ± 0.18 (median = 0.22) for the cleanup worker's and proxy's interviews, respectively. The agreement between two doses was better if the cleanup worker was interviewed rather than his proxy: the median ratio of current to reference dose was 1.0 and 0.56 for cleanup workers and proxies, respectively. The present study has shown that human factor uncertainties lead to underestimation or overestimation of the "true" reference dose for most cleanup workers up to 3 times. In turn, the potential impact of these errors on radiation-related risk estimates should be assessed.

Global DNA Methylation Profiles in Peripheral Blood of WTC-Exposed Community Members with Breast Cancer.

Breast cancer represents the most common cancer diagnosis among World Trade Center (WTC)-exposed community members, residents, and cleanup workers enrolled in the WTC Environmental Health Center (WTC EHC). The primary aims of this study were (1) to compare blood DNA methylation profiles of WTC-exposed community members with breast cancer and WTC-unexposed pre-diagnostic breast cancer blood samples, and (2) to compare the DNA methylation differences among the WTC EHC breast cancer cases and WTC-exposed cancer-free controls. Gene pathway enrichment analyses were further conducted. There were significant differences in DNA methylation between WTC-exposed breast cancer cases and unexposed prediagnostic breast cancer cases. The top differentially methylated genes were Intraflagellar Transport 74 (IFT74), WD repeat-containing protein 90 (WDR90), and Oncomodulin (OCM), which are commonly upregulated in tumors. Probes associated with established tumor suppressor genes (ATM, BRCA1, PALB2, and TP53) were hypermethylated among WTC-exposed breast cancer cases compared to the unexposed group. When comparing WTC EHC breast cancer cases vs. cancer-free controls, there appeared to be global hypomethylation among WTC-exposed breast cancer cases compared to exposed controls. Functional pathway analysis revealed enrichment of several gene pathways in WTC-exposed breast cancer cases including endocytosis, proteoglycans in cancer, regulation of actin cytoskeleton, axon guidance, focal adhesion, calcium signaling, cGMP-PKG signaling, mTOR, Hippo, and oxytocin signaling. The results suggest potential epigenetic links between WTC exposure and breast cancer in local community members enrolled in the WTC EHC program.

РАДИАЦИОННЫЕ РИСКИ РАКА ПРЕДСТАТЕЛЬНОЙ ЖЕЛЕЗЫ СРЕДИ ЛИКВИДАТОРОВ ПОСЛЕДСТВИЙ НА ЧАЭС (ПЕРИОД НАБЛЮДЕНИЯ 1996–2018 гг.)

Purpose: The paper deals with the occurrence of prostate cancer and mean survival time following a diagnosis of the disease among Chernobyl clean-up workers. Material and methods: Clinical and dosimetry data accumulated at the National Radiation and Epidemiological Registry (NRER) during the period from 1996 over 2018 were used for the study. The study cohort consisted of 69,698 men. During the follow-up 742 prostate cancer cases were detected, all patients had radiation dose records, the disease stage was established in 628 patients. To assess radiation risk maximum likelihood approach was used. Mean survival time was evaluated with the use of the relationship between a disease prevalence and newly detected disease cases intensity in a stationary population (diseases intensity is equal to intensity of mortality from all causes). Results: Excess relative risk of prostate cancer induction per 1 Gy was 0.74 (95 % CI: ‒0.31; 2.15) and it was statistically insignificant. Standardized incidence ratios between clean-up workers and male population of Russia within 95 % confidence limits do not differ from 1.0. Mean survival time after the disease diagnosis within the period from 1996 over 2018 was 3.5±1.3 years. The relationship between a survival time and a disease stage was estimated. Survival time for cases with 1–3 stages 3.3±2.9, 3.6±2.3, 4.3±2.7 years respectively. The less survival time for cases with stage 4 was 1.5±0.8 years. Mean mortality rate, i.e. the ratio of the number of clean-up workers died from prostate cancer to the total number of clean-up workers with diagnosed prostate cancer was 36.8 %, for stages 1–4 it was 20, 16, 37, 74 % respectively. Mean survival time in the groups with doses less than and higher than 150 mGy was 3.4±1.4 and 3.7±1.7, respectively. Presented data confirm the null hypothesis that there is no difference in survival times (p=0.20). Conclusion: Increase in prostate cancer incidence becomes the social problem not only in Russia but in other countries as well. The paper presents results of comprehensive radiation epidemiological analysis of prostate cancer incidence in cleanup workers, who constitute the representative sample of the Russian male population. The dose ‒ prostate cancer incidence relationship for the follow-up period from 1996 over 2018 is not statistically significant, although the value of excess relative risk per dose unit is positive. It is not unthinkable that the absence of statistical significance is caused due to limited length of the follow-up period. But at the same time, the fact that observed the standardized incidence ratio is 1.0 and characteristics of two groups with doses ≥150 mGy are similar, speaks of the lack of a significant radiation effect. The obtained results of the analysis confirm our view of the necessity to continue the study.

Impact of uncertainties in exposure assessment on thyroid cancer risk among cleanup workers in Ukraine exposed due to the Chornobyl accident.

A large excess risk of thyroid cancer was observed among Belarusian/Russian/Baltic Chornobyl cleanup workers. A more recent study of Ukraine cleanup workers found more modest excess risks of thyroid cancer. Dose errors in this data are substantial, associated with model uncertainties and questionnaire response. Regression calibration is often used for dose-error adjustment, but may not adequately account for the full error distribution. We aimed to examine the impact of exposure-assessment uncertainties on thyroid cancer among Ukrainian cleanup workers using Monte Carlo maximum likelihood, and compare with results derived using regression calibration. Analyses assessed the sensitivity of results to various components of internal and external dose. Regression calibration yielded an excess odds ratio per Gy (EOR/Gy) of 0.437 (95% CI -0.042, 1.577, p = 0.100), compared with the EOR/Gy using Monte Carlo maximum likelihood of 0.517 (95% CI -0.039, 2.035, p = 0.093). Trend risk estimates for follicular morphology tumors exhibited much more extreme effects of full-likelihood adjustment, the EOR/Gy using regression calibration of 3.224 (95% CI -0.082, 30.615, p = 0.068) becoming ~ 50% larger, 4.708 (95% CI -0.075, 85.143, p = 0.066) when using Monte Carlo maximum likelihood. Results were sensitive to omission of external components of dose. In summary, use of Monte Carlo maximum likelihood adjustment for dose error led to increases in trend risks, particularly for follicular morphology thyroid cancers, where risks increased by ~ 50%, and were borderline significant. The unexpected finding for follicular tumors needs to be replicated in other exposed groups.

Association of Deepwater Horizon Oil Spill Response and Cleanup Work With Risk of Developing Hypertension

Exposure to hydrocarbons, fine particulate matter (PM2.5), and other chemicals from the April 20, 2010, Deepwater Horizon disaster may be associated with increased blood pressure and newly detected hypertension among oil spill response and cleanup workers. To determine whether participation in cleanup activities following the disaster was associated with increased risk of developing hypertension. This cohort study was conducted via telephone interviews and in-person home exams. Participants were 6846 adults who had worked on the oil spill cleanup (workers) and 1505 others who had completed required safety training but did not do cleanup work (nonworkers). Eligible participants did not have diagnosed hypertension at the time of the oil spill. Statistical analyses were performed from June 2018 to December 2021. Engagement in cleanup activities following the Deepwater Horizon oil spill disaster, job classes, quintiles of cumulative total hydrocarbons exposure level, potential exposure to burning or flaring oil, and estimated PM2.5 were examined. Systolic and diastolic blood pressure measurements were collected during home exams from 2011 to 2013 using automated oscillometric monitors. Newly detected hypertension was defined as antihypertensive medication use or elevated blood pressure since the spill. Log binomial regression was used to calculate prevalence ratios (PR) and 95% CIs for associations between cleanup exposures and hypertension. Multivariable linear regression was used to estimate exposure effects on continuous blood pressure levels. Of 8351 participants included in this study, 6484 (77.6%) were male, 517 (6.2%) were Hispanic, 2859 (34.2%) were non-Hispanic Black, and 4418 (52.9%) were non-Hispanic White; the mean (SD) age was 41.9 (12.5) years at enrollment. Among workers, the prevalence of newly detected hypertension was elevated in all quintiles (Q) of cumulative total hydrocarbons above the first quintile (PR for Q3, 1.29 [95% CI, 1.13-1.46], PR for Q4, 1.25 [95% CI, 1.10-1.43], and PR for Q5, 1.31 [95% CI, 1.15-1.50]). Both exposure to burning and/or flaring oil and gas (PR, 1.16 [95% CI, 1.02-1.33]) and PM2.5 from burning (PR, 1.26 [95% CI, 0.89-1.71]) for the highest exposure category were associated with increased risk of newly detected hypertension, as were several types of oil spill work including cleanup on water (PR, 1.34 [95% CI, 1.08-1.66]) and response work (PR, 1.51 [95% CI, 1.20-1.90]). Oil spill exposures were associated with newly detected hypertension after the Deepwater Horizon disaster. These findings suggest that blood pressure screening should be considered for workers with occupational hydrocarbon exposures.

Haematological, renal, and hepatic function changes among Rayong oil spill clean-up workers: a longitudinal study.

The Rayong oil spill incident of 2013 leaked over 50,000 barrels of crude oil into the Gulf of Thailand. This study assessed trends and changes in the haematological, renal, and hepatic indices among the Rayong oil spill clean-up workers 5years after the spill. Haematological, renal, and hepatic indices measured for 570 oil spill clean-up workers at baseline and annually during 5-year follow-ups were analysed. Haemoglobin (Hb), haematocrit (Hct), white blood cell (WBC) count, red blood cell (RBC) count, and platelet count for haematological function, aspartate aminotransferase (AST) and alanine aminotransferase (ALT) for hepatic function, and creatinine (Cr) and blood urea nitrogen (BUN) for renal function were assessed. The longitudinal measures of haematological, renal and hepatic indices were analysed using analysis of variance for repeated measures. The generalised estimating equations (GEE) were used to assess trends of these indices and associated factors, including exposure level. Increasing trends were observed per year for WBC (0.52 ± 0.03 × 103 cells/μL), Cr (0.01 ± 0.00mg/dL), platelet (0.31 × 103 μL per year), and BUN (0.24 ± 0.03mg/dL). Decreasing trends of aspartate aminotransferase (AST) were observed (1.54 ± 0.21IU/L per year). Clean-up workers with high exposure to the oil spill had a significantly higher average of WBC and lower average of BUN than low-exposure and unknown-exposure workers. Gender and age were significantly associated with creatinine changes. Results of this study show the differences between baseline and follow-up haematological, renal, and hepatic indices and trends of these indices. The long-term changes in the indices in this study show worsening renal functions after oil spill and possibility of cardiovascular effects. These findings contribute to expanding knowledge on the long-term health effects of oil spills.

STATUS OF THE CELLULAR IMMUNITY IN CLEAN-UP WORKERS OF THE CHORNOBYL ACCIDENT AND PATIENTS WITH CANCER OF THE MOUTH CAVITY, ORAL AND LARYNGEAL PART OF THE PHARYNX

Objective: to establish cellular immunity in clean-up workers of the Chornobyl accident compared to patients with malignant neoplasms of the oral cavity, oral and laryngeal parts of the pharynx according to the subpopulation organization of peripheral blood leukocytes. Materials and methods. We examined 112 males, age (56,92 ± 6,17) years (M ± SD), including 26 male clean-up workers exposed at the radiation dose 10–500 mSv; 20 male clean-up workers exposed at the dose range 504–990 mSv; 33 patients with malignant neoplasms of the oral cavity, oral and laryngeal parts of the pharynx and 33 nonexposed subjects of the control group. Immune cell subsets analysis was performed by the expression of differential and activation antigens of peripheral blood leukocytes using flow cytometry. Results. In assessing each group's cellular immunity, there was a decrease in the number of CD19+ B-lymphocytes, CD3+HLA-DR+ T- and CD3-HLA-DR+ B-lymphocytes, CD3-16+56+ natural killer cells, combined with an increase in the number of CD8+ T-lymphocytes. An increase in the relative number of CD4+CD8+ T-lymphocytes was determined in clean-up workers (D ≤ 500 mSv) and cancer patients. An increase in the number of CD8+ T-lymphocytes and a decrease in the number of CD4+ T-lymphocytes were observed in clean-up workers (D &gt; 500 mSv), as well as in cancer patients. In addition, a decrease of monocytes, CD3+16+56+, and CD3+TCRαβ+ T-lymphocytes was determined in patients with oncological pathology. Conclusions. The obtained results show the unidirectionality of changes in cellular immunity in the participants of the liquidation of the consequences of the accident at the Chornobyl nuclear power plant and patients with the investigated oncological pathology, which indicates the formation of persistent violations of antitumor protection in the participants of the liquidation of the consequences of the accident as the basis of oncogenesis. Determining changes in the number of lymphocytes, monocytes, granulocytes, CD4+ T-lymphocytes, CD4+CD8+ immature T-lymphocytes, the immunoregulatory ratio CD4+ / CD8+, CD3+TCRαβ+ T-lymphocytes and CD3+16+56+ CTL can have an additional effect on the effectiveness antitumor protection and the probability of oncogenesis risk in immunocompromised individuals. Key words: ionizing radiation, Chornobyl, clean-up workers of the Chornobyl accident, neoplasms of the oral cavity, oral and laryngeal parts of the pharynx, immune system.

MEDICAL EXPERTISE FOR ESTABLISH CAUSATION OF DISEASE, LEADING TO LOSS OF HEALTH, DISABILITY AND DEATH WITH THE ACTION OF IONIZING RADIATION AND OTHER HARMFUL FACTORS OF THE CHORNOBYL ACCIDENT IN THE REMOTE POST-ACCIDENTAL PERIOD (2013-2022).

To study and characterize the structure of the affected categories (clean-up workers and victims) of the Chernobyl Catastrophe based on the materials of expert cases of the Central Interdepartmental Expert Commission (CMEC) in the remote post-accidental period (2013-2022). The work was performed in the design of a retrospective study that based on studying of 50,974 expert cases, which were considered by CIEC during 2013-2022 to establish a causal relationship between the disease and influence of radiation exposure and other harmful factors and conditions during ChNPP accident using a systematic analytical approach to assessing the medical and nonmedical parameters presented in medical expert documentation. The total number of affected adult citizens as on 01.01.2022, compared to 2008, decreased by 477,953 persons, or by 26.05 % (from 1,834,536 to 1,354,746 persons). The number of clean-up workers of the accident decreased from 276,327 (2013) to 171,725 (2022), or by 104,602 people (37.85 %), that means - during the last 10 years, almost every third clean-up worker who participated in the liquidation of the consequences of the accident at the Chernobyl NPP died. The number of adult victims decreased from 1,558,209 in 2008 to 1,183,021 in 2022, or by 24.08 % (375,188 persons). The average annual reduction in the absolute number of clean-up workers of ChNPP accident during 2013-2022 is about 7,770 people per year (9,424 during 2021), adult victims - 27,045 people per year (28,922 during 2021). In the structure of medical expert cases during 2013-2022 the leading place as the reason of disease, disability and death is occupied by oncological diseases - 52.72 %, cerebrovascular diseases and their complications make up 17.08 %, diseases of the cardiovascular system - 19.6 %. In the remote post-accidental period (2013-2022) has increased the need of expertise of the causal relationship of disability and the causes of death with the influence of the Chornobyl NPP accident consequences for medical and social support. During 2013-2022 period quick reducing for all categories of affected due to the Chornobyl NPP accident taken place. In the structure of medical expert cases during 2013-2022 the leading place as the reason of disease, disability and death is occupied by oncological diseases.