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Introduction The accident at the Chernobyl nuclear power plant was the largest radiation-ecological catastrophe, which was accompanied by a massive release of the radioactive isotope of iodine. The aim of this work was to investigate the incidence of thyroid cancer in Belarus and assess the risk of developing this disease in various groups of affected cohorts. Material and methods The data from the State Register of persons affected by the Chernobyl accident (from 1987 to 2015) and the data of the Belarusian Cancer Registry (from 1978 to 2015) were used in the study. The analysis was conducted using crude rates (CR), age-specific rates (AsR) and age-standardised rates (ASR) and standardised incidence ratio (SIR). Affected population was divided into four groups: liquidators (99 498 persons), evacuees (13 096 persons), residents of contaminated areas (139 811 persons) and their offspring (30 475 persons), which were analysed by sex, age at time of the disaster, year of being in contaminated area, duration of staying in contaminated area, density of radiation contamination and individualised doze in thyroid gland. Results and discussions It was shown the intensive increase in the incidence rates of thyroid cancer in the Belorussian population after the Chernobyl accident, which finished after 2001 (CR1986=1.5±0.24, CR2001=10.3±0.63, CR2015=12.5±0,71). Thyroid cancer growth was most significant in most contaminated Gomel, Mogilev and Brest areas. It was shown that the maximum increase in incidence was observed in persons aged 0–4 years at the time of the accident. In the affected population, significantly high risk of thyroid cancer was noted in all groups. The risk was highest in the evacuees in 1995–1999 (SIR=13.0 (9.21–17.70)) and was significantly higher than in the liquidators (SIR=4.4 (3.63–5.25)) and in the cohort of living in contaminated areas (SIR=2,4 (1.88–2.98)). The risk was higher in men than in women, for those who were children at the time of the accident and who were in the most contaminated areas. The dose-response relationship was shown for the evacuees (rSpearman=0.9, p=0.037) and for persons living in contaminated areas (rSpearman=1.0, p Conclusion In our work we have shown that Chernobyl disaster increased thyroid cancer incidence in both whole population and most affected groups. Especially in people who were children at the time of disaster. |
