Reanalysis of Epidemiological Investigation of Cancer Risk among People Residing near Nuclear Power Plants in South Korea

Abstract

Background: A 20-year follow-up study on cancer incidence among people living near nuclear power plants in South Korea ended in 2011 with a finding of significantly, but inconsistently, elevated thyroid cancer risk for females. Reanalysis of the original study was carried out to examine the dose–response relationship further, and to investigate any evidence of detection bias. Methods: In addition to replicating the original Cox proportional hazards models, nested case-control analysis was carried out for all subjects and for four different birth cohorts to examine the effects of excluding participants with pre-existing cancer history at enrollment. The potential for detection bias was investigated using the records of medical utilization and voluntary health checks of comparison groups. Results: The overall risk profile of the total sample was similar to that of the original study. However, in the stratified analysis of four birth cohorts, the cancer risk among people living near nuclear power plants became higher in younger birth cohorts. This was especially true for thyroid cancers of females (hazard ratio (HR) 3.38) and males (HR 1.74), female breast cancers (HR 2.24), and radiation-related cancers (HR 1.59 for males, HR 1.77 for females), but not for radiation-insensitive cancers (HR 0.59 for males, HR 0.98 for females). Based on medical records and health check reports, we found no differences between comparison groups that could have led to detection bias. Conclusions: The overall results suggest elevated risk of radiation-related cancers among residents living near nuclear power plants, controlling for the selective survival effect. This is further supported by the lack of evidence of detection bias and by records of environmental exposure from radiation waste discharge.

Spatial distribution and determinants of thyroid cancer incidence from 1999 to 2013 in Korea

“…Although ionizing radiation from the environment has been suggested as a risk factor for thyroid cancer 34 , 35 , we found no significant association between the distance from nuclear power plants and thyroid cancer incidence rate in this study. This finding is contrary to the findings of a previous study that reported women residing within a < 5 km radius from the nuclear power plant as being at high risk of thyroid cancer in Korea 36 . This may be because of the loss of information; the distance from the radiation facility to the center of Sigungu district, rather than the actual distance from each residence to nuclear power plant was used for analyses.…”

Long-term investigation of environmental radioactivity levels and public health around the Qinshan Nuclear Power Plant, China

“…The impacts of NPPs during operation have been studied in China 10 – 15 and many other countries 16 – 19 . Some of these studies focus on radioactive levels of environmental samples, such as drinking water, food, soil and air, and radiation doses of people living around NPPs, while other studies focus on population health risk and cancer incidence.…”

Study Protocol for Radiation Exposure and Cancer Risk Assessment: The Taiwan Nuclear Power Plants and Epidemiology Cohort Study (TNPECS)

“…Epidemiologic studies of cancer risks in residents near nuclear power plants (NPPs) have been carried out in at least eleven countries (South Korea, Canada, Finland, France, Germany, Great Britain, Japan, Spain, Sweden, Switzerland, and the United States) [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] . The majority of these studies investigated rates of cancer deaths or cancer incidence in residents living in various-distance geographic units, including counties and municipalities.…”