In 1986, immediately after the Chernobyl accident, the Ministry of Public Health of the USSR adopted a large-scale programme to establish in the country the All-Union Distribution Registry of persons affected by radiation. Towards 1992 (by the time of the disintegration of the USSR) the data base of the Registry included medical and dosimetric information for 659,292 men and that for 284,919 emergency workers (liquidators). All republics of the former Soviet Union as well as a wide range of scientific and practical institutions were involved in establishment of the registry. At present there is medical and dosimetric information for 370,120 men, including that for 159,027 liquidators of the accident, in the National Chernobyl Registry of Russia. Medical information (added annually) and dosimetric data allow radiation-epidemiological studies to be carried out on determination of possible dose dependence of morbidity, invalidism and mortality indices for persons affected by radiation and to compare actual data with prognostication estimates. In particular, epidemiological studies conducted in accordance with the case control technology of thyroid cancer diseases in children of the Bryansk region made it possible to determine a value of relative risk at the dose of 1 Gy which is equal to 7.15 (1.52; 33.8).
