Health risks of radiation exposure in the moderate-to-high dose range have been well established. However, the risk remains unclear at low-dose ranges with protracted low-dose rate exposure, which is typical of occupational exposure. The purpose of this study is to construct a cohort of Korean radiation workers and to assess health effects associated with occupational radiation exposure. The study population is expected to be about 190,000 Korean radiation workers who have been registered with the Nuclear Safety and Security Commission since 1984. The national dose registry, the national cancer registry, the national vital statistics registry, and the national health insurance data are collected based on the Nuclear Safety Act. Through the linkage of those collected data, we will evaluate radiation-induced health risks including cancer and non-cancer diseases.

The study population of this study is approximately 190000 Korean radiation workers registered with the Nuclear Safety and Security Commission since 1984. Diagnostic medical radiation workers were not included in the study population. The national dose registry, the national cancer registry, the national vital statistics registry, and the national health insurance data for radiation workers are collected retrospectively or prospectively based on the Nuclear Safety Act. Through the linkage of those collected data, we will evaluate radiation-induced health risks including cancer and non-cancer diseases. This data collection will be continued at 5-year intervals to update information on existing study participants and recruit newly hired workers if possible.

Age- and sex-specific standardized incidence and mortality ratios will be calculated for overall comparisons of cancer and non-cancer disease risks with general population. For dose-response assessment, excess relative risk (per Gy) and excess absolute risk (per Gy) will be estimated with adjustments for age and potential confounders, such as lifestyle factors and socioeconomic status.

Inclusion Criteria:

• Korean radiation workers in the national dose registry (except for diagnostic medical radiation workers)

Exclusion Criteria:

• Unidentified personal identification numbers
• Foreigner

Korean radiation workers in the national dose registry