• Title/Summary/Keyword: Epidemiological studies

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A Comparative Review of Radiation-induced Cancer Risk Models

  • Lee, Seunghee;Kim, Juyoul;Han, Seokjung
    • Journal of Radiation Protection and Research
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    • v.42 no.2
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    • pp.130-140
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    • 2017
  • Background: With the need for a domestic level 3 probabilistic safety assessment (PSA), it is essential to develop a Korea-specific code. Health effect assessments study radiation-induced impacts; in particular, long-term health effects are evaluated in terms of cancer risk. The objective of this study was to analyze the latest cancer risk models developed by foreign organizations and to compare the methodology of how they were developed. This paper also provides suggestions regarding the development of Korean cancer risk models. Materials and Methods: A review of cancer risk models was carried out targeting the latest models: the NUREG model (1993), the BEIR VII model (2006), the UNSCEAR model (2006), the ICRP 103 model (2007), and the U.S. EPA model (2011). The methodology of how each model was developed is explained, and the cancer sites, dose and dose rate effectiveness factor (DDREF) and mathematical models are also described in the sections presenting differences among the models. Results and Discussion: The NUREG model was developed by assuming that the risk was proportional to the risk coefficient and dose, while the BEIR VII, UNSCEAR, ICRP, and U.S. EPA models were derived from epidemiological data, principally from Japanese atomic bomb survivors. The risk coefficient does not consider individual characteristics, as the values were calculated in terms of population-averaged cancer risk per unit dose. However, the models derived by epidemiological data are a function of sex, exposure age, and attained age of the exposed individual. Moreover, the methodologies can be used to apply the latest epidemiological data. Therefore, methodologies using epidemiological data should be considered first for developing a Korean cancer risk model, and the cancer sites and DDREF should also be determined based on Korea-specific studies.

Manganese and Iron Interaction: a Mechanism of Manganese-Induced Parkinsonism

  • Zheng, Wei
    • Proceedings of the Korean Society of Toxicology Conference
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    • 2003.10b
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    • pp.34-63
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    • 2003
  • Idiopathic Parkinson's disease (IPD) represents a common neurodegenerative disorder. While epidemiological studies have suggested a number of risk factors including age, gender, race, and inherited disorder, the cumulative evidence supports the view that environmental or occupational exposure to certain chemicals may contribute to the initiation and progress of Parkinsonism.(omitted)

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Phylogenetic Analysis of the HIV-1 nef Gene from Korean Isolates

  • Lee, Dong-Hun;Yeup Yoon;Lee, Chan-Hee
    • Journal of Microbiology
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    • v.41 no.3
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    • pp.232-238
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    • 2003
  • Previous phylogenetic studies on human immunodeficiency virus type 1 (HIV-1) isolated from Korean patients suggest that the major subtype of Korean isolate is subtype B. In this subtype, some of the Korean isolates seem to be clustered exclusively of foreign isolates. Presence of this so-called “Korean clade” among Korean isolates is unique but needs verification since the number of Korean isolates used in previous studies was limited. This study aimed to identify the presence of the “Korean clade” by molecular phylogenetic analysis using all the Korean nef gene sequences registered in the NCBI GenBank (N=243) together with 32 reference strains and 77 foreign isolates. Extensive analysis of the nef gene nucleotide sequences by neighbor-joining method revealed the following. Most (83.1 %) of the Korean isolates belonged to subtype B, and 81.2% of subtype B were clustered together and excluded foreign isolates (bootstrap value=91.9% ). Within Korean subtype B cluster, no characteristic subcluster formation was evident since the bootstrap values for the subcluster were very low. Due to limited information, the phylogenetic analysis failed to identify the epidemiological linkage among specific groups such as homosexuals and hemophiliacs within the Korean subtype B cluster. Detailed analysis and epidemiological information are needed to clarify the origin and significance of the Korean subtype B cluster.

Phage typing of Staphylococcus aureus Isolates from Poultry Meat in Spain

  • Rosa Capita;Astorga, Maite-Alvarez;Calleja, Carlos-Alonso;Benito Moreno
    • Journal of Microbiology
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    • v.39 no.3
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    • pp.219-225
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    • 2001
  • Phage typing is currently used for typing of Staphylococcus aureus strains beyond the species level in epidemiological studies. A total of 168 Staphylococcus aureus isolates from chicken meat and chicken by-products were phage-typed using the international bacteriophage set for typing Staphylococcus aureus of human origin. One hundred and forty-eight (88.79%) strains were phage-typeable (at least one phage produced 20 or more plaques of lysis). Lysis by phages of group Ⅲ was the mast frequent with 99 (58.93%) sensitive strains. This fact coincides with results of other authors. Twenty-nine different phage patterns were observed and three (95, 75/84 and 6/1030/W57) were most common. One hundred and thirty-two (89.19% of typeable strains) skewed these or indistinguishable (only one phage reaction difference) patterns. Twenty-six out of seventy chicken samples (37.14%) harboured more than one phage type of Staphylococcus aureus. This fact emphasizes the convenience of subtyping several Staphylococcus aureus isolates from the same sample in epidemiological studies. 80% of sausages and hamburgers contained the same Staphylococcus aureus phage types, which wore not found in any of the other food types. This fact suggests a cross contamination during the processing of these foods. Phages 6, 75, 84, 1030 and W57 skewed the greatest activity. None of the Staphylococcus aureus strains were sensitive to phages 47, 81 and 94.

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Epidemiological Features of Human Papillomavirus (HPV) Infection among Women Living in Mainland China

  • Li, Jing;Huang, Rong;Schmidt, Johannes E.;Qiao, You-Lin
    • Asian Pacific Journal of Cancer Prevention
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    • v.14 no.7
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    • pp.4015-4023
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    • 2013
  • Cancer of the cervix is the third most common cancer in women worldwide, more than 85% of the cases occurring in developing countries such as China. In China, since a national cancer registry is already set up but with geographically limited data generated, the burden of cervical cancer is believed to be underestimated. High-risk human papillomavirus (HR-HPV) prevalence among women attending routine cervical cancer screening programs has been shown to correlate well with cervical cancer incidence rates based on independently obtained HPV prevalence data as well as findings for the worldwide cervical cancer burden. Therefore, reviewing data on HR-HPV prevalence in population-based screening studies and hospital-based case studies will be important in the context of better understanding the cervical cancer burden and for the evaluation of the potential impact of HPV vaccination in the country. With the advent of prophylactic vaccines, significant progress is likely to be made in cervical cancer prevention. This article reviews available data on the HPV epidemiology over a 12-year time period (2001-2012) in mainland China under different epidemiological aspects: by age group of study population, by ethnicity, by geographic area, as well as time period. The authors also review the potential acceptability of HPV vaccination among Chinese women.

When Work is Related to Disease, What Establishes Evidence for a Causal Relation?

  • Verbeek, Jos
    • Safety and Health at Work
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    • v.3 no.2
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    • pp.110-116
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    • 2012
  • Establishing a causal relationship between factors at work and disease is difficult for occupational physicians and researchers. This paper seeks to provide arguments for the judgement of evidence of causality in observational studies that relate work factors to disease. I derived criteria for the judgement of evidence of causality from the following sources: the criteria list of Hill, the approach by Rothman, the methods used by International Agency for Research on Cancer (IARC), and methods used by epidemiologists. The criteria are applied to two cases of putative occupational diseases; breast cancer caused by shift work and aerotoxic syndrome. Only three of the Hill criteria can be applied to an actual study. Rothman stresses the importance of confounding and alternative explanations than the putative cause. IARC closely follows Hill, but they also incorporate other than epidemiological evidence. Applied to shift work and breast cancer, these results have found moderate evidence for a causal relationship, but applied to the aerotoxic syndrome, there is an absence of evidence of causality. There are no ready to use algorithms for judgement of evidence of causality. Criteria from different sources lead to similar results and can make a conclusion of causality more or less likely.

The Clinical and Epidemiological Studies of Microsporulll gypsellm Infections (1976-2005) (최근 30년간 Microsporum gypseum의 감염 상태(1976-2005))

  • Bang, Young-Jun;Kim, Ssang-Young
    • Korean Journal of Clinical Laboratory Science
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    • v.40 no.2
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    • pp.80-85
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    • 2008
  • Microsporum gypseum is a geophilic fungus abundant in soil throughout the world. M. gypseum has been identified for the first time in Korea at 1976. The purpose of this study was to investigate epidemiologic aspects of M. gypseum. We performed the epidemiologic study an 198 patients with M. gypseum infections in from January 1976 to December 2005. From 100,012 patients, dermatophytes were isolated as follows; Trichophyton rubrum was isolated from 86,553 (86.5%), T. interdigitale 3,991 (4.0%), Epidermophyton floccosum 1.021 (0.1%), T. tonsurans 141 (0.1%). T. mentagrophytes 3.930 (3.9%), T. verrucosum 220 (0.2%), Microsporum canis 3.879 (3.9%), and M. gypseum 198 (0.2%). Number of patients with M. gypseum by site and age were as follows; most patients infected with tinea corporis were young people under 10 years. M. gypseum were most frequently isolated in summer and autumn.

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