Suicide Risk Among Chernobyl Cleanup Workers in Estonia Still Increased: An Updated Cohort Study

Abstract

The aim of the study is to examine the mortality experience among Chernobyl cleanup workers. A cohort study of 4786 men from Estonia who participated in the Chernobyl cleanup from 1986 to 1991 and were traced until December 31, 2002. Standardized mortality ratio (SMR) and adjusted mortality rate ratio (RR) derived through Poisson regression analysis were calculated. During follow-up, 550 deaths occurred, yielding an SMR of 1.01 (95% confidence interval [CI], 0.92-1.09). Increased risks were observed for suicide alone (SMR, 1.32; 95% CI, 1.03-1.67) and suicide combined with undetermined injury (SMR, 1.29; 95% CI, 1.03-1.60). One leukemia death occurred, and no thyroid cancer deaths were found. Elevated mortality also was observed for brain cancer (SMR, 2.78; 95% CI, 1.02-6.05). The adjusted RR for suicide remained stable over the time passed since return from the Chernobyl area, showing RRs of 1.09 (95% CI, 0.56-2.10) for 5 to 9 years and 1.00 (95% CI, 0.48-2.05) for 10 or more years compared with less than 5 years. During the 17 years after the accident, suicide risk in the cohort was greater than in the general male population. No elevated risk in overall mortality and radiation-related cancers was observed. The long-term nature of this elevated risk provides concrete evidence that psychological consequences represent the largest public health problem caused by the accident to date.