Cancer admission and mortality in workers exposed to ionizing radiation in Korea.

OBJECTIVE

Cancer mortality and morbidity are described for the first time in all Korean workers exposed to ionizing radiation.

METHODS

Based on hospital admissions, Standardized Rate Ratios (SRR) and Standardized Mortality Ratios (SMR) were modeled with Poisson regression.

RESULTS

Cancer admissions during 2000 to 2005 were low compared with autoworkers with the exception of nuclear power workers (SRR = 1.13, 95% CI = 0.94-1.36). Thyroid cancer was statistically significantly elevated in women radiation workers in medical (SRR = 2.90, 95% CI = 1.05-7.94) and research institutions (SRR = 3.91, 95% CI = 1.36-11.0) and industry (SRR = 5.07, 95% CI = 1.56-15.6), and in all nuclear power workers (SRR = 2.59, 95% CI = 1.33-5.13), and there was a significant association with dose (ERR = 20.4 per Sv, 90% CI = -8 to 60, one-tailed P = 0.049). The 935 deaths revealed a healthy worker effect for all causes (SMR = 0.58, 95% CI = 0.54-0.62) and all-cancer (SMR = 0.73, 95% CI = 0.64-0.82). Lung cancer (SMR = 0.77, 95% CI = 0.55-1.05) and leukemia (SMR = 0.59, 95% CI = 0.28-1.06) mortalities were also less than expected. Compared with autoworkers, radiation workers displayed decreased all-cause mortality except for nuclear power workers (statistically not significant).

CONCLUSIONS

ERRs as high as 300 per Sv appear to be ruled-out in this population with regulated exposure to ionizing radiation while ERRs as high as 100 per Sv are not.