Cancer morbidity among the emergency workers of the Chernobyl accident

The effects on human health of exposures to ionizing radiation have long been the subject of dispute. In this paper we focus on the primary cancer morbidity in the cohort of 8745 men who worked in the cleanup of the Chernobyl accident in 1986-1990 and were followed since exposure up to 1995. The official dosimetry data, mostly falling in the range of 0-25 cSv, are available for 75% of ameliorators. Annual cancer morbidity rates turned out to increase rapidly. However, trend analysis in the age-specific subgroups provides evidence that the observed temporal gradients are to be attributed to the ageing (regression coefficients for the age groups of 40-44; 45-49; 50-54 are 0.201; 0.793 and 1.223, correspondingly). In the five-year age groups cancer morbidity of the emergency workers (EWs) makes no statistically significant differences with that of the male populations of Russia and St-Petersburg. No evidence of an association between radiation dose and cancer morbidity was observed. The highest primary cancer morbidity is registered among those EWs, who arrived to Chernobyl region within 360 days followed the accident and had been working there during less than 30 or more than 180 days. The follow-up of the cohort is to be continued. (author)