Hospital assessment of the dynamics of mortality and primary disability after a stroke among Chernobyl liquidators in the Left-bank Ukraine (modern view of the problem and own research)
Authors: Onopriyenko O.P. , Trishchynska M.A. , Kolosova T.V. 
Published: November 2024

Background. The article highlights the global problem of stroke. When writing the review article, PubMed (1990–2018) and Up-To-Date (2016) resources were used. An urgent problem worldwide in the second decade of the 21st century is the high level of morbidity and increasing disability among the population after a stroke. Stroke ranks second among diseases with fatal consequences and is the most common cause of permanent disability. In 2015, stroke caused 6.7 million deaths worldwide. Mortality due to stroke is predicted to increase to 7.8 million in 2030. Psychogenic and environmental factors, along with pollution, have an impact on epidemiological health indicators, as noted by the authors on the 38th anniversary of the Chernobyl nuclear disaster (April 26, 1986) and on the 13th anniversary of the Fukushima nuclear accident (Fukushima-1, March 11–12, 2011). They compared data specifically related to strokes in Japan after the earthquake and disaster due to which humanity once again faced the threat of a nuclear monster exactly 25 years after Chernobyl. A linear non-threshold dose-effect dependence has long been established for cardiovascular and cerebrovascular pathology at radiation doses from 0 to 5 Gy. Even though a sufficient number of materials have been accumulated so far, which are reliable evidence of the influence of low-dose radiation (both external and internal) on the development of non-neoplastic morbidity and mortality from non-neoplastic diseases (cardiovascular, cerebrovascular), there is no single point of view on the problem. For a statistical solution to a very urgent problem, in particular, an objective assessment of the radiation consequences of the Chernobyl disaster, the international organizations WHO and IAEA consider it necessary to conduct further and long-term stu­dies. The purpose was to study the density of radioactively contaminated territories (RCT) and their residents, including Chernobyl liquidators, who suffered a stroke, to investigate the dynamics of functional and fatal stroke outcomes, and to study modern risk factors for a stroke. Materials and methods. A study was conducted of the density of contamination with radioactive cesium-137, strontium-90 (hereinafter 137Cs, 90Sr) of the RCT in the 4th controlled zone of the Left-bank region of the Brovary district within five villages above the Desna River. The subject of the research was primarily adult residents of the villages of this region, who gave their consent to conduct radiometric research on themselves, their soil and food products (water, milk, fish, poultry, berries, mushrooms). Results. So, in the Pohreby village, 137Cs was found in the soil — 54.9 Сi/km2, while in the Litochky village, the dose of 137Cs in the soil was lower, 31.9 Сi/km2. But 137Cs in food products, in particular in milk, had the highest indicators in the Puhivka and Litky villages — 7.0 Bq/l, with permissible levels of 137Cs and 90Sr radionuclides in milk of up to 20 Bq/l. The prognostic dose of 137Cs for 70 years was noted in the Pohreby village, 8.7 mSv/year. The cumulative dose of 137Cs as for 2013 among residents of the 4th RCT was on average 0.51–0.78 mSv/year. The morbidity and mortality from stroke among Chernobyl liquidators and residents of the RCT was high, namely 65.5 and 15.6 per 10,000 adult population, respectively, while these epidemiological indicators for the district in 2016 were 44.5 and 10.1, respectively, and for Ukraine — 29.9 and 13.3 per 10,000 population. An important question, the answer to which is given in the article, is the accumulation of 90Sr in the bones of those who died from a stroke, and 137Cs in the brain matter, as well as studies of neurodestruction processes in patients with moderate and severe ischemic stroke by evaluating the content of the NSE protein in blood serum, and neuroproliferation processes in the brain — by the content of the S100 protein. Presumably, the high epidemiological indicators of stroke in our region over a ten-year period are explained by the permanent influence of psychogenic risk factors (stress, anxiety, depression, hopelessness), small doses of internal radiation, and in Chernobyl liquidators — external radiation as well. The combination of these factors could in turn cause exacerbation of hypertension, diabetes, heart disease in patients. Apparently, comorbid conditions had a significant impact on functional and fatal stroke outcomes. The issue is addressed of how to optimize a specialized care for patients with stroke, improve prevention in the population living in the RCT. Conclusions. Studies have been conducted of the radioactively contaminated territories and their residents, inclu­ding Chernobyl liquidators who have suffered a stroke, the dynamics of functional and fatal stroke outcomes have been investigated, and modern stroke risk factors have been studied. At the maximum doses of external irradiation of the whole body, the highest reliably confirmed excess relative risks per unit dose (Gy–1) were found in patients with stroke — 3.48 (2.48; 4.88) who also had diabetes as a risk factor for a stroke — 3.41 (2.04; 5.75), which corresponds to the literature data. Research on the definition and quantitative assessment of the risks of developing a stroke among the evacuated population under the exposure to small doses of ionizing radiation is promising and of great importance for radiation medicine and radiobiology in general, since currently the blind spot is the study of the effects of incorporated radiation. Vascular pathology in the structure of morbidity among Chernobyl liquidators ranks second after tumors and blood diseases, which have the highest percentage of mortality and disability. The answers to the questions raised become a cornerstone in overcoming the stroke epidemic. Based on the above, there is a need to continue research in this area, to develop as soon as possible and to implement a scientific concept for prevention, early detection of the main modifiable risk factors of stroke together with a wide range of specialist physicians, compliance with proper treatment of stroke, which ill undoubtedly reduce the rate of mortality, disability from stroke, improve the quality of life of patients and their relatives.