Case-control analysis of leukemia among Chernobyl accident emergency workers residing in the Russian Federation, 1986-1993

This paper presents an analysis of data of the Russian National Medical and Dosimetric Registry (RNMDR) on the incidence of leukemia among Chernobyl accident emergency workers (EWs) who are resident in the Russian Federation (RF) for the period from 1986 through the end of 1993. It describes the system of a collection and a verification of data on leukemia. The analysis deals with 48 cases of leukemia diagnosed and verified among EWs. Distributions of leukemia cases by date of diagnosis, age, radiation dose, date of entry into the Chernobyl zone, date of exit from the zone, duration of stay in the region of Chernobyl were calculated. To evaluate leukemia risks associated with various factors the case-control methodology was used. Radiation dose, date of entry into and date of exit from the zone, duration of stay in the zone were used as risk factors. No significant associations between leukemia risks and the investigated factors were found. Calculations of standardised incidence ratios (SIR) revealed a significant increase in the incidence of leukemia among EWs of all dates of entry into the zone (SIR: 205, 99% confidence interval (CI): 105-305) and EWs entered the zone in 1986-1987 (SIR: 200, 95% CI: 118-282) compared to the general male population of the RF in 1991-1993.