BACKGROUND: The Korea Radiation Effect & Epidemiology Cohort METHODS: Using the KREEC-R raw data, we calculated age standardized rates (ASRs) of female thyroid cancer and re-analyzed the results of survey on the use of medical services. We also marked the administrative districts of residents who received the Radiation Health Research Institute (RHRI) health examinations and those in which thyroid cancer case occurred as per the Chonnam National University Research Institute of Medical Sciences (RIMS) final report on maps where the locations of NPPs and 5 km-radii around them were also indicated. And we compared the incidence rates of Radiation-induced cancer measured between the first period when RHRI health examinations were not yet implemented, and the second period when the RHRI health examinations were implemented. RESULTS: The ASR for the far-distance group, which comprised residents living in areas outside the 30 km radius of the NPPs, increased rapidly after 2000; however, that of the exposed group, which comprised residents living within a 5 km radius of the NPPs, started to increase rapidly even before 1995. The frequencies of the use of medical services were significantly higher in the intermediate proximate group, which comprised residents living within a 5–30 km radius of the NPPs, than in the exposed group in women. In case of female thyroid cancer, the second period ASR was higher than the first period ASR, but in case of female liver cancer and female stomach cancer no significant difference were observed between the periods. On map, many administrative districts of residents who received RHRI health examinations and most administrative districts in which thyroid cancer case occurred on RIMS final report were outside 5 km-radii around NPPs. CONCLUSIONS: We could not find any evidence supporting the assertion that detection bias influenced the increased risks of female thyroid cancer observed in the exposed group of the KREEC-R study, as opposed to the control group.
Academies and Institutes ; Bias (Epidemiology) ; Cohort Studies ; Epidemiology ; Female ; Humans ; Incidence ; Jeollanam-do ; Korea ; Liver Neoplasms ; Neoplasms, Radiation-Induced ; Nuclear Power Plants ; Radiation Effects ; Radius ; Stomach Neoplasms ; Thyroid Gland ; Thyroid Neoplasms

Inevitable human exposure to ionizing radiation from man-made sources has been increased with the proceeding of human civilization and consequently public concerns focus on the possible risk to human health. Moreover, Fukushima nuclear power plant accidents after the 2011 East-Japan earthquake and tsunami has brought the great fear and anxiety for the exposure of radiation at low levels, even much lower levels similar to natural background. Health effects of low dose radiation less than 100 mSv have been debated whether they are beneficial or detrimental because sample sizes were not large enough to allow epidemiological detection of excess effects and there was lack of consistency among the available experimental data. We have reviewed an extensive literature on the low dose radiation effects in both radiation biology and epidemiology, and highlighted some of the controversies therein. This article could provide a reasonable view of utilizing radiation for human life and responding to the public questions about radiation risk. In addition, it suggests the necessity of integrated studies of radiobiology and epidemiology at the national level in order to collect more systematic and profound information about health effects of low dose radiation.
DNA Damage/drug effects ; Environmental Exposure ; Humans ; Leukemia/epidemiology/etiology ; Neoplasms, Radiation-Induced/epidemiology ; *Radiation Dosage ; Radiation Tolerance ; *Radiation, Ionizing ; Radioactive Hazard Release ; Risk

Radon is likely the second most common cause of lung cancer after smoking. We estimated the lung cancer risk due to radon using common risk models. Based on national radon survey data, we estimated the population-attributable fraction (PAF) and the number of lung cancer deaths attributable to radon. The exposure-age duration (EAD) and exposure-age concentration (EAC) models were used. The regional average indoor radon concentration was 37.5 95 Bq/m3. The PAF for lung cancer was 8.3% (European Pooling Study model), 13.5% in males and 20.4% in females by EAD model, and 19.5% in males and 28.2% in females by EAC model. Due to differences in smoking by gender, the PAF of radon-induced lung cancer deaths was higher in females. In the Republic of Korea, the risk of radon is not widely recognized. Thus, information about radon health risks is important and efforts are needed to decrease the associated health problems.
Adult ; Demography ; *Environmental Exposure ; Female ; Humans ; Lung Neoplasms/*epidemiology/etiology/mortality ; Male ; Models, Theoretical ; Neoplasms, Radiation-Induced/*epidemiology/etiology ; Radon/*toxicity ; Republic of Korea/epidemiology ; Risk Assessment ; Smoking ; Survival Analysis

No abstract available.
Female ; Humans ; Male ; Neoplasms, Radiation-Induced/*epidemiology

No abstract available.
Adult ; Carcinogens/toxicity ; Environmental Exposure ; Genome, Human/radiation effects ; Humans ; Neoplasms, Radiation-Induced/epidemiology/etiology/*genetics ; *Nuclear Power Plants ; Republic of Korea/epidemiology ; Thyroid Neoplasms/epidemiology/etiology/*genetics

No abstract available.
Female ; Humans ; Male ; Neoplasms, Radiation-Induced/*epidemiology

No abstract available.
Female ; Humans ; Male ; Neoplasms, Radiation-Induced/*epidemiology

This study evaluated cancer risk for adult residents near Nuclear Power Plants (NPPs) in Korea through a valid prospective cohort study during 1992-2010. The study cohort was composed of 11,367 adults living within a five km radius from the NPPs for the exposed and 24,809 adults for the non-exposed or reference cohort set at two different levels of proximity; 5-30 km radius and more than 30 km radius away from NPPs. In 303,542.5 person-years of follow-up, a total of 2,298 cancer cases of all sites, or 1,377 radio-inducible cancers diagnosed during 1992-2008 were ascertained. Multiple adjusted hazard ratios and 95% confidence intervals were estimated using multivariate Cox proportional hazard model. There were no epidemiological evidence for increased risk of cancer due to radiation from NPPs. Radiological study results or surveillance data of radiation doses around NPPs could be well documented for risk estimation of radio-inducible cancers, instead of epidemiological study results of the long-time required. Continuous surveillance of quantitative measures of dose levels around NPPs and radiation exposures to the residents is warranted.
Adult ; Aged ; Aged, 80 and over ; Cohort Studies ; Female ; Follow-Up Studies ; Humans ; Incidence ; Male ; Middle Aged ; Neoplasms, Radiation-Induced/*epidemiology ; Nuclear Power Plants ; Proportional Hazards Models ; Prospective Studies ; Republic of Korea/epidemiology ; Risk Factors

Chernobyl Nuclear Accident ; Humans ; Japan ; epidemiology ; Neoplasms, Radiation-Induced ; etiology ; mortality ; Nuclear Warfare ; Radiation Dosage ; Radiation Injuries ; etiology ; mortality ; Radioactive Hazard Release ; Risk ; Ukraine ; epidemiology

OBJECTIVES: The objective of this study was to calculate sample size and power in an ongoing cohort, Korea radiation effect and epidemiology cohort (KREEC). METHOD: Sample size calculation was performed using PASS 2002 based on Cox regression and Poisson regression models. Person-year was calculated by using data from '1993-1997 Total cancer incidence by sex and age, Seoul' and Korean statistical informative service. RESULTS: With the assumption of relative risk=1.3, exposure:non-exposure=1:2 and power=0.8, sample size calculation was 405 events based on a Cox regression model. When the relative risk was assumed to be 1.5 then number of events was 170. Based on a Poisson regression model, relative risk=1.3, exposure:non-exposure=1:2 and power=0.8 rendered 385 events. Relative risk of 1.5 resulted in a total of 157 events. We calculated person-years (PY) with event numbers and cancer incidence rate in the non-exposure group. Based on a Cox regression model, with relative risk=1.3, exposure:non-exposure=1:2 and power=0.8, 136 245PY was needed to secure the power. In a Poisson regression model, with relative risk=1.3, exposure:non-exposure=1:2 and power=0.8, person-year needed was 129517PY. A total of 1939 cases were identified in KREEC until December 2007. CONCLUSIONS: A retrospective power calculation in an ongoing study might be biased by the data. Prospective power calculation should be carried out based on various assumptions prior to the study.
Adolescent ; Adult ; Aged ; Aged, 80 and over ; Child ; Child, Preschool ; Cohort Studies ; Dose-Response Relationship, Radiation ; Female ; Humans ; Incidence ; Infant ; Infant, Newborn ; Male ; Middle Aged ; Neoplasms, Radiation-Induced/*epidemiology ; Republic of Korea/epidemiology ; Risk ; Young Adult