• Title/Summary/Keyword: Epidemiological Model

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A study on the Establishment of Korean PTWI for Cadmium Based on The Epidemiological Data (국내역학조사에 기초한 한국인의 카드뮴 PTWI 설정 연구)

  • Choi, Chan-Woong;Moon, Jin-Hyun;Park, Hyoung-Su;Ryeom, Tai-Kyung;Lee, Kwang-Ho;Lee, Hyo-Min
    • Journal of Food Hygiene and Safety
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    • v.24 no.4
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    • pp.378-384
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    • 2009
  • There are differences of Cadmium (Cd) urinary concentration which is considered as indicator of renal tubular dysfunction in other countries, so we have reviewed domestic epidemiological data and suggested Korean health based guidance value (HBGV) for Cd to improve an efficiency of risk management. We decided to apply the WHO calculation model which considered the relationship between dietary intake and Cd concentration in urine sample. It is determined that Cd concentration 2.5 ug/g creatinine in urine as the prevalence of renal tubular dysfunction based on epidemiological data, because there is no renal tubular dysfunction and injury/lesion such as proteinuria at the concentration of 11.63 ug/g creatinine which is the highest Cd concentration in urine from the domestic epidemiological data. It is identified that the ratio between the Cd dietary consumption (8.3~10.4 ug/day) and Cd urinary concentration (0.38 ug/g creatinine) in Korean adult who predicting never been exposed to Cd are 21.8~27.3 and then it is applied to the corresponding model suggested by WHO. Also it is applied that 10% of bioavailability and 50% of excretion rate of absorbed to body (the ratio is 24) were assumed. The estimate of daily Cd consumption level which begins tubular dysfunction is 1 ug/kg bw/day, so we suggest the Korean provisional tolerable weekly intake (PTWI) as 7 ug/kg bw/week.

Estimated Risk of Radiation Induced Contra Lateral Breast Cancer Following Chest Wall Irradiation by Conformal Wedge Field and Forward Intensity Modulated Radiotherapy Technique for Post-Mastectomy Breast Cancer Patients

  • Athiyaman, Hemalatha;M, Athiyaman;Chougule, Arun;Kumar, HS
    • Asian Pacific Journal of Cancer Prevention
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    • v.17 no.12
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    • pp.5107-5111
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    • 2016
  • Background: Epidemiological studies have indicated an increasing incidence of radiation induced secondary cancer (SC) in breast cancer patients after radiotherapy (RT), most commonly in the contra-lateral breast (CLB). The present study was conducted to estimate the SC risk in the CLB following 3D conformal radiotherapy techniques (3DCRT) including wedge field and forward intensity modulated radiotherapy (fIMRT) based on the organ equivalent dose (OED). Material and Methods: RT plans treating the chest wall with conformal wedge field and fIMRT plans were created for 30 breast cancer patients. The risks of radiation induced cancer were estimated for the CLB using dose-response models: a linear model, a linear-plateau model and a bell-shaped model with full dose response accounting for fractionated RT on the basis of OED. Results: The plans were found to be ranked quite differently according to the choice of model; calculations based on a linear dose response model fIMRT predict statistically significant lower risk compared to the enhanced dynamic wedge (EDW) technique (p-0.0089) and a non-significant difference between fIMRT and physical wedge (PW) techniques (p-0.054). The widely used plateau dose response model based estimation showed significantly lower SC risk associated with fIMRT technique compared to both wedge field techniques (fIMRT vs EDW p-0.013, fIMRT vs PW p-0.04). The full dose response model showed a non-significant difference between all three techniques in the view of second CLB cancer. Finally the bell shaped model predicted interestingly that PW is associated with significantly higher risk compared to both fIMRT and EDW techniques (fIMRT vs PW p-0.0003, EDW vs PW p-0.0032). Conclusion: In conclusion, the SC risk estimations of the CLB revealed that there is a clear relation between risk associated with wedge field and fIMRT technique depending on the choice of model selected for risk comparison.

Development of Predictive Model for Annual Mean Radon Concentration for Assessment of Annual Effective dose of Radon Exposure (라돈 노출 유효선량 평가를 위한 연간 평균 라돈 농도 예측모델 개발)

  • Lee, Cheolmin;Kang, Daeyong;Koh, Sangbaek;Cho, Yongseog;Lee, Dajeong;Lee, Sulbee
    • Journal of Environmental Science International
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    • v.25 no.8
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    • pp.1107-1114
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    • 2016
  • This research, sponsored by the Korean Ministry of Environment in 2014, was the first epidemiological study in Korea that investigated the health impact assessment of radon exposure. Its purpose was to construct a model that calculated the annual mean cumulative radon exposure concentrations, so that reliable conclusions could be drawn from environment-control group research. Radon causes chronic lung cancer. Therefore, the long-term measurement of radon exposure concentration, over one year, is needed in order to develop a health impact assessment for radon. Hence, based on the seasonal correction model suggested by Pinel et al.(1995), a predictive model of annual mean radon concentration was developed using the year-long seasonal measurement data from the National Institute of Environmental Research, the Korea Institute of Nuclear Safety, the Hanyang University Outdoor Radon Concentration Observatory, and the results from a 3-month (one season) survey, which is the official test method for radon measurement designated by the Korean Ministry of Environment. In addition, a model for evaluating the effective annual dose for radon was developed, using dosimetric methods. The model took into account the predictive model for annual mean radon concentrations and the activity characteristics of the residents.

Protective Effect of Antler in Experimental Colon Carcinogenesis

  • Kim, Dong-Hyun;Park, Hae-Young;Kim, Nam-Jae;Kim, Jae-Kun;Won, Do-Hee;Hong, Nam-Doo
    • Natural Product Sciences
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    • v.5 no.1
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    • pp.48-53
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    • 1999
  • There are epidemiological evidences that the population with high fecal ${\beta}-glucuronidase$ activity has greater risk of colon cancer than the population with low fecal ${\beta}-glucuronidase$. This relationship was investigated by using the mouse-dimethylhydrazine colon carcinogenesis model and the extract of antler which was a ${\beta}-glucuronidase$ inhibitor. Mice with low fecal ${\beta}-glucuronidase$ activity induced by administration of water and Folch's fraction of antler had significantly fewer aberrant crypts after injections of 1,2-dimethylhydrazine (DMH) than mice treated with DMH alone. The result supports the hypothesis that the inhibitor of ${\beta}-glucuronidase$ such as antler extract can protect an animal against the induction of colon cancer.

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Bayesian Spatiotemporal Modeling in Epidemiology: Hepatitis A Incidence Data in Korea (역학분야에서의 베이지안 공간시간 모델링: 한국 A형 간염 자료)

  • Choi, Jungsoon
    • The Korean Journal of Applied Statistics
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    • v.27 no.6
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    • pp.933-945
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    • 2014
  • Bayesian spatiotemporal analysis is of considerable interest to epidemiological applications because health data is collected over space-time with complicated dependency structures. A basic concept in spatiotemporal modeling is introduced in this paper to analyze space-time disease data. The paper reviews a range of Bayesian spatiotemporal models and analyzes Hepatitis A data in Korea.

COVID-19 and Return-To-Work for the Construction Sector: Lessons From Singapore

  • Gan, Wee Hoe;Koh, David
    • Safety and Health at Work
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    • v.12 no.2
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    • pp.277-281
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    • 2021
  • Singapore's construction sector employs more than 450,000 workers. During the height of the COVID-19 pandemic in Singapore from April to June 2020, migrant workers were disproportionately affected, including many working in the construction sector. Shared accommodation and construction worksites emerged as nexuses for COVID-19 transmission. Official government resources, including COVID-19 epidemiological data, 43 advisories and 19 circulars by Singapore's Ministries of Health and Manpower, were reviewed over 8 month period from March to October 2020. From a peak COVID-19 incidence of 1,424.6/100,000 workers in May 2020, the incidence declined to 3.7/100,000 workers by October 2020. Multilevel safe management measures were implemented to enable the phased reopening of construction worksites from July 2020. Using the Swiss cheese risk management model, the authors described the various governmental, industry, supervisory and worker-specific interventions to prevent, detect and contain COVID-19 for safe resumption of work for the construction sector.

Determinants of Inflation Expectations of South Korean Consumers (한국 소비자의 기대 인플레이션 결정요인)

  • Young-Bin Ahn
    • Asia-Pacific Journal of Business
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    • v.14 no.4
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    • pp.413-429
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    • 2023
  • Purpose - The purpose of this study is to investigate the determinants of consumers' inflation expectations using consumers' inflation perceptions and the sub-components of consumer price index (CPI) basket in South Korea based on a consumer survey conducted by the Bank of Korea (BOK). Design/methodology/approach - Using Carroll's (2003) epidemiological model, we analyzed data from January 2013 to January 2023, resulting in a data set of 121 observations for both inflation perceptions and inflation expectations. This study focuses only on aggregate inflation expectations and perceptions because of data availability from the BOK. Findings - Professionals' forecasts play a major role in forming consumers' inflation expectations, whereas the actual headline CPI and consumers' inflation perceptions do not. These results remain robust when including the sub-components of the CPI basket in the analysis. Research implications or Originality - It would be the most efficient way to suppress professionals' expected inflation in fighting against a substantial spike in consumers' inflation expectations. To guide consumers' inflation expectations based on BOK's inflation targeting, the bank needs to consider professionals' forecasts in devising monetary policies.

Association between small for gestational age and risk of autism spectrum disorders: a meta-analysis

  • Jenabi, Ensiyeh;Bashirian, Saeid;Asali, Zahra;Seyedi, Mahdieh
    • Clinical and Experimental Pediatrics
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    • v.64 no.10
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    • pp.538-542
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    • 2021
  • Background: The relationship between small for gestational age (SGA) and autism spectrum disorders (ASDs) remains unknown. Purpose: This meta-analysis aimed to investigate the relationship between SGA and the risk of ASD. Methods: We searched PubMed, Web of Science, and Scopus databases from inception to November 2020. The heterogeneity across studies was explored using the I2 statistic. The possibility of publication bias was assessed using Begg test. The results were reported using the odds ratio (OR) and 95% confidence interval (CI) using a random-effects model. Results: The literature search yielded 824 articles with 8,752,138 participants. We assessed the association between SGA and the risk of ASD in cohort and case-control studies. Based on the random-effects model, compared with SGA, the estimated OR of the risk of ASD was 1.17 (95% CI, 1.09-1.24). Therefore, there was a significant association between SGA and the risk of ASD. Conclusion: Based on OR reports in epidemiological studies, we showed that SGA is a risk factor for and can increase the risk of ASD. The association between SGA and ASD risk has further relevance to the current public health emphasis on appropriate prepregnancy weight and pregnancy weight gain.

The Effects of COVID-19 Diffusion in the Korean Economy: Using SIR-based Macro-Epidemiological Model (코로나19 확산이 거시경제에 미치는 영향 분석: SIR 기반의 거시역학 모형을 중심으로)

  • Choi, Bongseok;Park, Hojeong
    • Environmental and Resource Economics Review
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    • v.30 no.1
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    • pp.27-48
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    • 2021
  • We extend and modify the canonical epidemiology model of Eichenbaum, Rebelo and Trabandt (2020) to investigate the general equilibrium effects of COVID-19 spread in the Korean economy when vaccine, treatment and social distancing are available. Particularly, we develop a SIR-macro model which considers possibility of moral inattention of the overconfident agents through which people is more likely to be infected. Our model implies that people's decision to cut back on consumption and work reduces the severity of the epidemic and thus exacerbate the size of the economic recession caused by the epidemic. Another finding is that the average 13 weeks to develop the vaccine and treatment will lead to 2% drop of consumption.

Study on the Methodology of the Microbial Risk Assessment in Food (식품중 미생물 위해성평가 방법론 연구)

  • 이효민;최시내;윤은경;한지연;김창민;김길생
    • Journal of Food Hygiene and Safety
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    • v.14 no.4
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    • pp.319-326
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    • 1999
  • Recently, it is continuously rising to concern about the health risk being induced by microorganisms in food such as Escherichia coli O157:H7 and Listeria monocytogenes. Various organizations and regulatory agencies including U.S.FPA, U.S.DA and FAO/WHO are preparing the methodology building to apply microbial quantitative risk assessment to risk-based food safety program. Microbial risks are primarily the result of single exposure and its health impacts are immediate and serious. Therefore, the methodology of risk assessment differs from that of chemical risk assessment. Microbial quantitative risk assessment consists of tow steps; hazard identification, exposure assessment, dose-response assessment and risk characterization. Hazard identification is accomplished by observing and defining the types of adverse health effects in humans associated with exposure to foodborne agents. Epidemiological evidence which links the various disease with the particular exposure route is an important component of this identification. Exposure assessment includes the quantification of microbial exposure regarding the dynamics of microbial growth in food processing, transport, packaging and specific time-temperature conditions at various points from animal production to consumption. Dose-response assessment is the process characterizing dose-response correlation between microbial exposure and disease incidence. Unlike chemical carcinogens, the dose-response assessment for microbial pathogens has not focused on animal models for extrapolation to humans. Risk characterization links the exposure assessment and dose-response assessment and involve uncertainty analysis. The methodology of microbial dose-response assessment is classified as nonthreshold and thresh-old approach. The nonthreshold model have assumption that one organism is capable of producing an infection if it arrives at an appropriate site and organism have independence. Recently, the Exponential, Beta-poission, Gompertz, and Gamma-weibull models are using as nonthreshold model. The Log-normal and Log-logistic models are using as threshold model. The threshold has the assumption that a toxicant is produce by interaction of organisms. In this study, it was reviewed detailed process including risk value using model parameter and microbial exposure dose. Also this study suggested model application methodology in field of exposure assessment using assumed food microbial data(NaCl, water activity, temperature, pH, etc.) and the commercially used Food MicroModel. We recognized that human volunteer data to the healthy man are preferred rather than epidemiological data fur obtaining exact dose-response data. But, the foreign agencies are studying the characterization of correlation between human and animal. For the comparison of differences to the population sensitivity: it must be executed domestic study such as the establishment of dose-response data to the Korean volunteer by each microbial and microbial exposure assessment in food.

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