RESEARCH – October 2016

The Estonian Study of Chernobyl Cleanup Workers: cancer incidence (1986–2012) and mortality (1986–2014)

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Abstract

Background. After the Chernobyl accident in 1986 hundreds of thousands of people were sent to radioactive contaminated environment for cleanup activities. Among them there were 4831 men from Estonia. The health status of Estonian Chernobyl cleanup workers has been followed-up for a long time period; it has been found that they were exposed to low radiation doses and that their cancer and death risk, with the exception of suicide, was not elevated.

Objective. To examine site-specific cancer incidence (1986–2012) and cause-specific mortality (1986–2014) in the Estonian Chernobyl cleanup workers cohort in comparison with the male population of Estonia.

Methods. The data of 4811 traced males in the cohort, who took part at the environmental cleanups in the Chernobyl area in 1986–1991 were linked to the Estonian Population Registry, Estonian Cancer Registry and Estonian Causes of Death Registry. To estimate the health effects of exposure in the cohort, standardized incidence ratios (SIRs) for cancer sites, and standardized mortal ity ratios (SMRs) for the causes of death were calculated. Risk measures were accompanied by the 95% confidence interval (CI).

Results. In 1986–2012, a total of 369 incident cases of cancer were diagnosed in the cohort (SIR = 1.12; 95% CI 1.00–1.23). The risk of leukemia was not statistically significantly increased (SIR = 1.25; 95% CI 0.60–2.29). An elevated risk of alcohol-related cancers (SIR = 1.58; 95% CI 1.28–1.88) occurred. During the period 1986–2014, 1176 cleanup workers died. (SMR = 1.04; 95% CI 0.98–1.10). An excess risk of suicides (SMR = 1.30; 95% CI 1.05–1.59) was noted.

Conclusion. Cancer incidence and mortality of Chernobyl cleanup workers did not differ from that of the male population of Estonia. The only exception was relatively high suicide mortality that points to the urgent necessity for dealing with cleanup workers’ mental health issues at the state level.