Epidemiological Study of Korean Radiation Workers (KRWS)

April 15, 2026 updated by: Korea Institute of Radiological & Medical Sciences

Health Effects Associated With Occupational Radiation Exposure Among Korean Radiation Workers (Korean Radiation Workers Study)

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.

Study Overview

Status

Active, not recruiting

Conditions

Intervention / Treatment

Detailed Description

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.

Study Type

Observational

Enrollment (Actual)

196379

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • South Korea
    • Nowon-gu
      • Seoul, Nowon-gu, South Korea, 01812
        • Korea Institute of Radiological & Medical Sciences

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

15 years and older (Child, Adult, Older Adult)

Accepts Healthy Volunteers

No

Sampling Method

Non-Probability Sample

Study Population

Korean radiation workers in the national dose registry

Description

Inclusion Criteria:

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

Exclusion Criteria:

  • Unidentified personal identification numbers
  • Foreigner

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

Cohorts and Interventions

Group / Cohort
Intervention / Treatment
Korean radiation workers
The study population is Korean radiation workers exposed to ionizing radiation in workplaces. Diagnostic medical radiation workers were not included in the study population.
Radiation: Occupational radiation exposure
Ionizing radiation in workplaces

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Radiation-induced cancer risk
Time Frame: year 4
Cancer risk associated with occupational radiation exposure
year 4
Radiation-induced cancer risk
Time Frame: year 9
Cancer risk associated with occupational radiation exposure
year 9

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Radiation-induced non-cancer risk
Time Frame: year 4
Non-cancer disease risk associated with occupational radiation exposure
year 4
Radiation-induced non-cancer risk
Time Frame: year 9
Non-cancer disease risk associated with occupational radiation exposure
year 9

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Korea Institute of Radiological & Medical Sciences

Investigators

  • Principal Investigator: Songwon Seo, Ph.D., Korea Institute of Radiological & Medical Sciences

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

November 18, 2021

Primary Completion (Actual)

December 31, 2022

Study Completion (Estimated)

March 31, 2031

Study Registration Dates

First Submitted

May 9, 2022

First Submitted That Met QC Criteria

May 13, 2022

First Posted (Actual)

May 19, 2022

Study Record Updates

Last Update Posted (Actual)

April 20, 2026

Last Update Submitted That Met QC Criteria

April 15, 2026

Last Verified

March 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 50091

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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