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Role of radiation and non-radiation factors on the development of coronary heart disease in the Chornobyl clean-up workers: epidemiological study results
L. I. Krasnikova, V. O. Buzunov
State Institution “National Research Center for Radiation Medicine of the National Academy of MedicalSciences of Ukraine”, Melnykov str., 53, Kyiv, 04050, Ukraine
Objective. The objective of this study was to establish the risks for coronary heart disease in the Chornobyl clean-up workers with regard to a whole-body external radiation dose and non-radiation (biological, social-and-hygienic and behavioral) factors.
Materials and methods. Risk-analysis was based on the cohort of the Chornobyl male clean-up workers 1986–1987 (8,625 men, including 3,623 with available whole-body external doses). Data of clinical-and-epidemiological registry, National Research Centre for Radiation Medicine were used for 1992–2013 monitoring period. We used the internal control group with radiation doses less than 0.05 Gy.
Results. Statistically significant radiation risks in the Chornobyl clean-up workers were established for the coronary heart disease at doses 0.15–0.249 Gy, 0.25–0.99 Gy, 1 Gy and more (dose group 0.15–0.249 Gy RRY=1.9 (1.2; 3.1), ERR=4.6 (1.5; 14.9) Gy-1, EAR=64.2 cases per 1000 person-years, Gy); among exposed people aged 40 years and older – at doses 0.5–0.99 Gy (RRY=1.4 (1.05; 1.81), ERR=0.5 (0.03; 1.1) Gy-1, EAR=30.5 cases per 1000 person-years, Gy). Statistically significant risks for the disease under consideration were also identified with regard to non-radiation factors (smoking, improper physical training, adverse working conditions, diseases etc; age and psychoemotional overstrain were of a particular impact). Non-radiation factors are at most responsible for development of coronary heart disease. For this reason the control of potential confounding factors is required to assess the effect of the radiation factor both at a stage of comparison groups selection and analysis using the Mantel-Haenszel method.
Key words: Chornobyl accident, Chornobyl clean-up workers, registries, coronary heart disease, radiation and non-radiation factors, risk.
Problems of radiation medicine and radiobiology. 2014;19:67-79.
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