• Title, Summary, Keyword: cohort analysis

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Review on Cohort Projects in Domestic and Overseas and Establishment of Cohort on Korean Medicine (국내외 코호트 사업 고찰 및 한의학 코호트 구축)

  • Kim, Jiyoung;Baek, Younghwa;Lee, Siwoo;Ko, Kwang Pil;Yoo, Jonghyang
    • Journal of Society of Preventive Korean Medicine
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    • v.20 no.1
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    • pp.65-73
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    • 2016
  • Objectives : In this study, we investigated the trends of cohort project in domestic and overseas, and suggested the necessity of cohort on korean medicine and the direction of research. Methods : The papers which include cohort in the title and published by 2015 were searched using PubMed. In order to study the history of cohort in domestic and overseas, research trend was investigated based on the websites of each cohort projects and traditional medicine searching engine named OASIS. Results : Using PubMed, 42,802 papers were searched. Most of the studies over 50 % of total articles, however, were conducted in these 6 years. Nevertheless, cohort studies are being actively proceed, the korean medicine based on cohort studies are nonexistent. Therefore, further discussion about cohort study on korean medicine is necessary to gather physiological index and clinical index of korean medicine consistently. Conclusions : Systematically constructed cohort on korean medicine would be the foundation which collects information, such as gene information, bio information, dietary habit, life style, and Pattern identification (辨證), and integrates them. The analysis of massive clinical materials could suggest the basis of Prevention and treatment of korean medicine considering the difference between personal.

Hormonal Replacement Therapy and the Risk of Lung Cancer in Women: An Adaptive Meta-analysis of Cohort Studies

  • Bae, Jong-Myon;Kim, Eun Hee
    • Journal of Preventive Medicine and Public Health
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    • v.48 no.6
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    • pp.280-286
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    • 2015
  • Objectives: Approximately 10% to 15% of lung cancer cases occur in never-smokers. Hormonal factors have been suggested to lead to an elevated risk of lung cancer in women. This systematic review (SR) aimed to investigate the association between hormonal replacement therapy (HRT) and the risk of lung cancer in women using cohort studies. Methods: We first obtained previous SR articles on this topic. Based on these studies we made a list of refereed, cited, and related articles using the PubMed and Scopus databases. All cohort studies that evaluated the relative risk of HRT exposure on lung cancer occurrence in women were selected. Estimate of summary effect size (sES) with 95% confidence intervals (CIs) were calculated. Results: A total of 14 cohort studies were finally selected. A random effect model was applied due to heterogeneity (I-squared, 64.3%). The sES of the 14 articles evaluating the impact of HRT exposure on lung cancer occurrence in women indicated no statistically significant increase in lung cancer risk (sES, 0.99; 95% CI, 0.90 to 1.09). Conclusions: These results showed that HRT history had no effect on the risk of lung cancer in women, even though the sES of case-control studies described in previous SR articles indicated that HRT had a protective effect against lung cancer. It is necessary to conduct a pooled analysis of cohort studies.

Chronic Hepatitis B Virus Infection and Risk of Pancreatic Cancer: A Meta-analysis

  • Li, Lei;Wu, Bo;Yang, Li-Bo;Yin, Guan-Cheng;Liu, Ji-Yong
    • Asian Pacific Journal of Cancer Prevention
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    • v.14 no.1
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    • pp.275-279
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    • 2013
  • Objectives: A number of studies have shown that chronic hepatitis B virus infection is implicated in susceptibility to pancreatic cancer. However, the results are still controversial. This meta-analysis aimed to quantitatively assess the relationship between chronic hepatitis B virus infection and incidence of pancreatic cancer of cohort and case-control studies. Methods: A literature search was performed for entries from 1990 to 2012 using PUBMED and EMBASE. Studies were included if they reported odds ratios (ORs) and corresponding 95% CIs of pancreatic cancer with respect to the infection of hepatitis B virus. Results: Eight studies met the inclusion criteria, which included five case-control studies and three cohort studies. Compared with individuals who have not infection of hepatitis B virus, the pooled OR of pancreatic cancer was 1.403 (95%CI: 1.139-1.729, P=0.001) for patients with hepatitis B virus infection. Sub-group analysis by study design showed that the summary OR was 1.43 (95%CI: 1.06-1.94, P=0.021) when pooling case-control studies and 1.31 (95%CI: 1.00-1.72, P=0.05) when pooling cohort studies. Conclusion: Findings from this meta-analysis suggest that chronic hepatitis B virus infection may increase the risk of pancreatic cancer. This relationship needs to be confirmed by further follow-up studies.

Association Between C-reactive Protein and Risk of Cancer: A Meta-analysis of Prospective Cohort Studies

  • Guo, Yong-Zhong;Pan, Lei;Du, Chang-Jun;Ren, Dun-Qiang;Xie, Xiao-Mei
    • Asian Pacific Journal of Cancer Prevention
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    • v.14 no.1
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    • pp.243-248
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    • 2013
  • Background: Associations between elevated C-reactive protein (CRP) and cancer risk have been reported for many years, but the results from prospective cohort studies remains controversial. A meta-analysis of prospective cohort studies was therefore conducted to address this issue. Methods: Eligible studies were identified by searching the PubMed and EMBASE up to October 2012. Pooled hazard ratios (HR) was calculated by using random effects model. Results: Eleven prospective cohort studies involving a total of 194,796 participants and 11,459 cancer cases were included in this meta-analysis. The pooled HR per natural log unit change in CRP was 1.105 (95% confidence interval (CI): 1.033-1.178) for all-cancer, 1.308 (95% CI: 1.097-1.519) for lung cancer, 1.040 (95% CI: 0.910-1.170) for breast cancer, 1.063 (95% CI: 0.965-1.161) for prostate cancer, and 1.055 (95% CI: 0.925-1.184) for colorectal cancer. Dose-response analysis showed that the exponentiated linear trend for a change of one natural log unit in CRP was 1.012 (95% CI: 1.006-1.018) for all-cancer. No evidence of publication bias was observed. Conclusions: The results of this meta-analysis showed that the elevated levels of CRP are associated with an increased risk of all-cancer, lung cancer, and possibly breast, prostate and colorectal cancer. The result supports a role of chronic inflammation in carcinogenesis. Further research effort should be performed to identify whether CRP, as a marker of inflammation, has a direct role in carcinogenesis.

The Change of Work Careers in Youth Cohort pre and post-the Economic Crisis- (외환위기 전후 청년 코호트의 노동경력 비교)

  • Moon, Hey Jin
    • Korean Journal of Social Welfare
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    • v.65 no.1
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    • pp.201-226
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    • 2013
  • This study aims to identify changes in early work career of youth cohort entering the labor market pre and post-the economic crisis and compare career pathway types of different cohorts. Labor market experiences of youth cohort were constructed by sequencing the number of organizations, kinds of jobs, the scale of the business, and type of employment. In addition, a holistic sequence was created by including complementary factors. In this sense, the labor market experience in this study was conceptualized as a process involving continuous sequences and hierarchical and orderly changes which differs from a simple job mobility. Sequence analysis involving Optimal Matching method was conducted to examine whether such cohort-differences in labor market experiences were related to differences in distribution of career pathway types. The result showed that the post-economic crisis cohort had a relatively higher likelihood of falling into the non-employment type, unemployment type, non-corporate employment type, irregular employment type, and mobile employment type. These findings provide empirical evidence supporting the hypothesis that the employment precariousness of cohort has exacerbated after the economic crisis.

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Population Analysis of the Common Squid, Todarodes pacificus Steenstrup in Korean Waters 2. Morphological analysis (한국해역에 분포하는 오징어의 계군분석 2. 형태학적 분석)

  • KIM Yeong-hye;KANG Yong-joo;BAIK Chul-in
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.30 no.5
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    • pp.903-905
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    • 1997
  • Morphological differences were studied using the analysis of covariance between various partial length and mantle length of the common Todarodes pacificus by cohorts in the Korean waters. Analysis of seven morphological characters proved that each cohort has no sexual differences, except significant sexual differences only in the Summer cohort in term of relative growth between mantle length and body weight. The three cohorts represent significant differences in morphological characters.

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외국의 코호트 연구 현황

  • Jo Seong-Il
    • 대한예방의학회:학술대회논문집
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    • pp.30-37
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    • 2003
  • o Cohort study became the major approach to study of chronic diseases such as CVD and cancer o Cohort can be population-based or volunteer-based o Types of be population-be categorized by source population and selection mechanism o More and more cohort studies involve biological specimens, such as blood, urine, toenail, cheek cells, etc. o Multi-center and multi-national collaboration is an effective way to increase sample size. o Current statistical method typically use time-to-event analysis by Cox proportional hazard model.

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Income Inequality Decomposed by Age, Period and Cohort Effects: A Comparison of the Capital and Non-Capital Regions (연령, 시간, 코호트효과를 고려한 소득 불평등: 수도권과 비수도권 간 비교)

  • Jeong, Jun Ho
    • Journal of the Economic Geographical Society of Korea
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    • v.23 no.2
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    • pp.166-181
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    • 2020
  • This paper attempts to compare and analyze the intensity, trend, and regional gap of income inequality, capitalizing upon the Age-Period-Cohort model which considers age, time and cohort effects, with the 1998-2018 Korea Labor Panel (KLIPS) survey data for respondents living in the Capital and Non-Capital Regions. The main analysis results are as follows. First, in the case of both cohort and age effects, those in their 50~60s, including the so-called baby boomers and '386 generation' living in the Capital Region, have relatively lower income inequality effect compared to that of other age groups and cohorts in the Non-Capital Region. Second, the micro-individual characteristics cannot be ignored to account for a regional gap in income inequality, but rather the effects of structural and institutional omitted variables and the social discrimination effects of individual characteristics variables are more significant in explaining it. Overall, intra-and inter-cohort income inequalities appear to overlap.

Alcohol Intake and Risk of Thyroid Cancer: A Meta-Analysis of Observational Studies

  • Hong, Seung-Hee;Myung, Seung-Kwon;Kim, Hyeon Suk;The Korean Meta-Analysis (KORMA) Study Group
    • Cancer Research and Treatment
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    • v.49 no.2
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    • pp.534-547
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    • 2017
  • Purpose The purpose of this study was to assess whether alcohol intake is associated with the risk of thyroid cancer by a meta-analysis of observational studies. Materials and Methods We searched PubMed and EMBASE in June of 2015 to locate eligible studies. We included observational studies such as cross-sectional studies, case-control studies, and cohort studies reporting odd ratios (ORs) or relative risk (RRs) with 95% confidence intervals (CIs). Results We included 33 observational studies with two cross-sectional studies, 20 case-controls studies, and 11 cohort studies, which involved a total of 7,725 thyroid cancer patients and 3,113,679 participants without thyroid cancer in the final analysis. In the fixed-effect model meta-analysis of all 33 studies, we found that alcohol intake was consistently associated with a decreased risk of thyroid cancer (OR or RR, 0.74; 95% CI, 0.67 to 0.83; $I^2=38.6%$). In the subgroup meta-analysis by type of study, alcohol intake also decreased the risk of thyroid cancer in both case-control studies (OR, 0.77; 95% CI, 0.65 to 0.92; $I^2=29.5%$; n=20) and cohort studies (RR, 0.70; 95% CI, 0.60 to 0.82; $I^2=0%$; n=11). Moreover, subgroup meta-analyses by type of thyroid cancer, gender, amount of alcohol consumed, and methodological quality of study showed that alcohol intake was significantly associated with a decreased risk of thyroid cancer. Conclusion The current meta-analysis of observational studies found that, unlike most of other types of cancer, alcohol intake decreased the risk of thyroid cancer.

Trends and Age-Period-Cohort Effects on the Incidence and Mortality Rate of Cervical Cancer in Korea

  • Moon, Eun-Kyeong;Oh, Chang-Mo;Won, Young-Joo;Lee, Jong-Keun;Jung, Kyu-Won;Cho, Hyunsoon;Jun, Jae Kwan;Lim, Myong Cheol;Ki, Moran
    • Cancer Research and Treatment
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    • v.49 no.2
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    • pp.526-533
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    • 2017
  • Purpose This study was conducted to describe the trends and age-period-cohort effects on the incidence and mortality rate of cervical cancer in Korea. Materials and Methods The incidence and mortality rate of cervical cancer among ${\geq}20-year-old$ women from 1993 to 2012 were obtained from the Korea Central Cancer Registry and the Korean Statistical Information Service. Age-standardized rates were calculated and Joinpoint regression was used to evaluate the trends in the incidence and mortality rate. Age-period-cohort analysis was performed to investigate the independent effects of age, period and cohort. Results The incidence of cervical cancer decreased from 32.8 per 100,000 in 1993 to 15.9 per 100,000 in 2012 (annual percent change [APC], -3.9%; 95% confidence interval [CI], -4.2% to -3.6%). The mortality rate decreased from 5.2 per 100,000 in 1993 to 2.1 per 100,000 in 2012 (APC, -4.8%; 95% CI, -5.1% to -4.4%); however, the incidence and mortality rates among young women (< 30 years old) increased. An age-period-cohort model of the incidence and mortality rate showed decreasing period effects between 1993 and 2008 and decreasing cohort effects between 1928 and 1973, while birth cohorts after 1973 exhibited slight increases in the incidence and mortality rate of cervical cancer. Conclusion Recent decreases in the incidence and mortality rate of cervical cancer were due to decreases in the period and cohort effects, which reflect the implementation of a cancer screening program and changes in lifestyle. However, our findings also highlighted an increase in cohort effects on the incidence and mortality rate among young women born after 1973.