A Cohort Study of Korean Radiation Workers: Baseline Characteristics of Participants

The Korean Radiation Worker Study investigated the health effects of protracted low-dose radiation among nuclear-related occupations in the Nuclear Safety and Security Commission in Korea. From 2016&ndash
2017, 20,608 workers were enrolled (86.5% men and 30.7% nuclear power plant workers). The mean cumulative dose &plusmn
standard deviation between 1984 and 2017 (1st quarter) was 11.8 &plusmn
28.8 (range 0&ndash
417) mSv. Doses below recording level (&le
0.1 mSv) were reported in 7901 (38.3%) cases
431 (2%) had cumulative doses &ge
100 mSv. From 1999&ndash
2016, 212 cancers (189 men, 23 women) occurred
thyroid cancer predominated (39.2%, 72 men, 11 women). In men, the standardized incidence ratio (SIR) for all cancers was significantly decreased (SIR = 0.76, 95% CI 0.66&ndash
0.88)
however, that for thyroid cancer was significantly increased (SIR = 1.94, 95% CI 1.54&ndash
2.44). Compared to the non-exposed group (&le
0.1 mSv), the relative risk (RR) in the exposed group (&gt
0.1 mSv) after adjusting for sex, attained age, smoking status, and duration of employment was 0.82 (95% CI 0.60&ndash
1.12) for all cancers and 0.83 (95% CI 0.49&ndash
1.83) for thyroid cancer. The preliminary findings from this baseline study with a shorter follow-up than the latency period for solid cancer cannot exclude possible associations between radiation doses and cancer risk.