• Title, Summary, Keyword: cohort analysis

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Post-diagnosis Soy Food Intake and Breast Cancer Survival: A Meta-analysis of Cohort Studies

  • Chi, Feng;Wu, Rong;Zeng, Yue-Can;Xing, Rui;Liu, Yang;Xu, Zhao-Guo
    • Asian Pacific Journal of Cancer Prevention
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    • v.14 no.4
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    • pp.2407-2412
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    • 2013
  • Background and Objectives: Data on associations between soy food intake after cancer diagnosis with breast cancer survival are conflicting, so we conducted this meta-analysis for more accurate evaluation. Methods: Comprehensive searches were conducted to find cohort studies of the relationship between soy food intake after cancer diagnosis and breast cancer survival. Data were analyzed with comprehensive meta-analysis software. Results: Five cohort studies (11,206 patients) were included. Pooling all comparisons, soy food intake after diagnosis was associated with reduced mortality (HR 0.85, 95%CI 0.77 0.93) and recurrence (HR 0.79, 95%CI 0.72 0.87). Pooling the comparisons of highest vs. lowest dose, soy food intake after diagnosis was again associated with reduced mortality (HR 0.84, 95%CI 0.71 0.99) and recurrence (HR 0.74, 95%CI 0.64 0.85). Subgroup analysis of ER status showed that soy food intake was associated with reduced mortality in both ER negative (highest vs. lowest: HR 0.75, 95%CI 0.64 0.88) and ER positive patients (highest vs. lowest: HR 0.72, 95%CI 0.61 0.84), and both premenopausal (highest vs. lowest: HR 0.78, 95%CI 0.69 0.88) and postmenopausal patients (highest vs. lowest: HR 0.81, 95%CI 0.73 0.91). In additioin, soy food intake was associated with reduced recurrence in ER negative (highest vs. lowest: HR 0.64, 95%CI 0.44 0.94) and ER+/PR+ (highest vs. lowest: HR 0.65, 95%CI 0.49 0.86), and postmenopausal patients (highest vs. lowest: HR 0.67, 95%CI 0.56 0.80). Conclusion: Our meta-analysis showed that soy food intake might be associated with better survival, especially for ER negative, ER+/PR+, and postmenopausal patients.

Population Aging and Wage Structure: An Empirical Study of Cohort Size Effect on Korean Male Worker since 1990 (인구 고령화와 임금구조: 1990년대 이후 한국 남성 근로자의 세대규모효과에 대한 실증분석)

  • Eom, Dong-Wook
    • Korea journal of population studies
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    • v.31 no.1
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    • pp.75-97
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    • 2008
  • Recently Korea is expected with the decrease of population in working ages and also population structure, especially age structure, has changed as aging goes faster. This study focuses on the relationship between age structure and wage structure to analyzes the cohort size effect on the change of age-earnings profile. Our empirical analysis based on Wright(1991)'s model takes weighted OLS regression using the male worker's data of Ministry of Labor 'Wage Structure Survey'($1990{\sim}2006$). In pooled data, we take the conclusion that the cohort size effect was found in high school and college graduate workers, but the effect is different between them. The labor market entry effect of high school graduate workers is negative(-) and his persistent effect is positive(+). On the other hand, the cohort size effect of college graduate workers have appeared the opposite directions in contrary with the existing results of Welch(1979) and Wright(1991). This results are seen as the possibility that college graduate worker has the benefit of wage level by his relative cohort size in spite of high unemployment of young graduate. It will be the sign of need that we should interest in the change of age structure with balancing the labor supply side approach and the demand side study which the previous studies was mainly tended to focus on.

Occupational Exposure to Trichloroethylene and Non-hodgkin Lymphoma Risk (직업적 트리클로로에틸렌 노출과 비호지킨림프종의 연관성)

  • Chun, Jae-Buhm;Han, So-Hee;Yoon, Hyung-Suk;Lee, Eun-Jung;Lee, Kyoung-Mu
    • Journal of Environmental Health Sciences
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    • v.37 no.5
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    • pp.358-368
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    • 2011
  • Objectives: In order to evaluate the association between occupational exposure to chloroethylene (TCE) and risk of non-Hodgkin lymphoma (NHL), we conducted a meta-analysis of retrospective cohort studies and casecontrol studies and attempted to summarize the evidence of the association from molecular-epidemiological studies and experiments with human cells. Methods: In the meta-analysis, we restricted the analysis to those studies with data for chlorinated solvents, degreasers, or TCE. Studies involving dry cleaners or launderers were excluded from the analysis because use of TCE as a dry cleaning fluid has been rare since the 1960s. The data were combined using a random-effects model to estimate the summary risks (OR and RR) and 95% confidence intervals (CIs). Molecular evidence of the effect of TCE on human immune system were also reviewed and summarized. Results: Occupational exposure to TCE was strongly associated with NHL among cohort studies (number of studies=13, summary RR=1.33, 95% CI=1.04-1.70) whereas the association was not statistically significant among case-control studies (number of studies=15, summary OR=1.10, 0.98-1.23). When exposure level was considered, it became statistically significant for the highest exposure level (number of studies=5, summary OR=1.70, 1.25-2.32). Molecular evidences showed that TCE exposure in human or cultured human cells may cause a significant decrease immune cell subsets and changes in hormone levels related to immune response. Conclusions: Our results from meta-analysis and additional molecular evidence suggest that occupational exposure to TCE may cause NHL. However, unmeasured potential confounding and unclear dose-response relationships warrant further study on the role of TCE exposure in NHL carcinogenesis.

Alcohol Consumption and Breast Cancer Survival: A Metaanalysis of Cohort Studies

  • Gou, Yun-Jiu;Xie, Ding-Xiong;Yang, Ke-Hu;Liu, Ya-Li;Zhang, Jian-Hua;Li, Bin;He, Xiao-Dong
    • Asian Pacific Journal of Cancer Prevention
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    • v.14 no.8
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    • pp.4785-4790
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    • 2013
  • Background and Objectives: Evidence for associations between alcohol consumption with breast cancer survival are conflicting, so we conducted the present meta-analysis. Methods: Comprehensive searches were conducted to find cohort studies that evaluated the relationship between alcohol consumption with breast cancer survival. Data were analyzed with meta-analysis software. Results: We included 25 cohort studies. The meta-analysis results showed that alcohol consumption was not associated with increased breast cancer mortality and recurrence after pooling all data from highest versus lowest comparisons. Subgroup analyses showed that pre-diagnostic or post-diagnostic consumpotion, and ER status did not affect the relationship with breast cancer mortality and recurrence. Although the relationships of different alcohol consumption with breast cancer mortality and recurrence were not significant, there seemed to be a dose-response relationship of alcohol consumption with breast cancer mortality and recurrence. Only alcohol consumption of >20 g/d was associated with increased breast cancer mortality, but not with increased breast cancer recurrence. Conclusion: Although our meta-analysis showed alcohol drinking was not associated with increased breast cancer mortality and recurrence, there seemed to be a dose-response relationship of alcohol consumption with breast cancer mortality and recurrence and alcohol consumption of >20 g/d was associated with increased breast cancer mortality.

An Analysis of Job Selection, Major-Job Match and Wage Level of College Graduates (대학 졸업생의 직업선택과 임금 수준)

  • Park, Jae-Min
    • Journal of Korea Technology Innovation Society
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    • v.14 no.1
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    • pp.22-39
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    • 2011
  • This study examines the wage level from a viewpoint of major-job match as part of an analysis on the skill mismatch problem in 4-year college graduates. The empirical analysis explicitly incorporate the sample selection bias as an econometric problem not only suggested but merely introduced in the earlier studies. This study also set up a major-job match variable, which was usually handled as a binary variable for analytical convenience, as a polychotomous choice variable in selection equation as provided by the survey. In particular, it considered multi-cohort survey on graduates of the years 1982, 1992, and 2002 for the empirical analysis. As a result of empirical analysis, the wage premium of a major-job match was identified. This result was consistent after the consideration of a sample selection bias and also after modeling the major-job match variable as polychotomously selective. Through an analysis classified by the major, this study identified a relatively high wage premium among Social Science, Engineering, and Science majors. However, there was a difference in the effect of selection among these majors. Also, by assessing cohort effects this study found that the skill mismatch had rapidly progressed in 1992, while difference between 1992 and 2002 cohorts are insignificant. The analysis suggests that wage level is better understood within the context of both sample selection and major-job match, and regardless of model specification the major-job match affects wage strongly.

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Perceptions and practices of commensality and solo-eating among Korean and Japanese university students: A cross-cultural analysis

  • Cho, Wookyoun;Takeda, Wakako;Oh, Yujin;Aiba, Naomi;Lee, Youngmee
    • Nutrition Research and Practice
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    • v.9 no.5
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    • pp.523-529
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    • 2015
  • BACKGROUND/OBJECTIVES: Commensality, eating together with others, is a major representation of human sociality. In recent time, environments around commensality have changed significantly due to rapid social changes, and the decline of commensality is perceived as a serious concern in many modern societies. This study employs a cross-cultural analysis of university students in two East Asian countries, and examines cross-cultural variations of perceptions and actual practices of commensality and solo-eating. SUBJECTS/METHODS: The analysis was drawn from a free-list survey and a self-administrative questionnaires of university students in urban Korea and Japan. The free-listing survey was conducted with a small cohort to explore common images and meanings of commensality and solo-eating. The self-administrative questionnaire was developed based on the result of the free-list survey, and conducted with a larger cohort to examine reasons and problems of practices and associated behaviors and food intake. RESULTS: We found that Korean subjects tended to show stronger associations between solo-eating and negative emotions while the Japanese subjects expressed mixed emotions towards the practice of solo-eating. In the questionnaire, more Korean students reported they prefer commensality and tend to eat more quantities when they eat commensally. In contrast, more Japanese reported that they do not have preference on commensality and there is no notable difference in food quantities when they eat commensally and alone. Compared to the general Korean cohort finding, more proportion of overweight and obese groups of Korean subjects reported that they tend to eat more when they are alone than normal and underweight groups. This difference was not found in the overweight Japanese subjects. CONCLUSION: Our study revealed cross-cultural variations of perceptions and practices of commensality and solo-eating in a non-western setting.

No Association Between Tea Consumption and Risk of Renal Cell Carcinoma: A Meta-analysis of Epidemiological Studies

  • Hu, Zheng-Hui;Lin, Yi-Wei;Xu, Xin;Chen, Hong;Mao, Ye-Qing;Wu, Jian;Xu, Xiang-Lai;Zhu, Yi;Li, Shi-Qi;Zheng, Xiang-Yi;Xie, Li-Ping
    • Asian Pacific Journal of Cancer Prevention
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    • v.14 no.3
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    • pp.1691-1695
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    • 2013
  • Objective: To evaluate the association between tea consumption and the risk of renal cell carcinoma. Methods: We searched PubMed, Web of Science and Scopus between 1970 and November 2012. Two evaluators independently reviewed and selected articles based on predetermined selection criteria. Results: Twelve epidemiological studies (ten case-control studies and two cohort studies) were included in the final analysis. In a meta-analysis of all included studies, when compared with the lowest level of tea consumption, the overall relative risk (RR) of renal cell carcinoma for the highest level of tea consumption was 1.03 (95% confidence interval [CI] 0.89-1.21). In subgroup meta-analyses by study design, there was no significant association between tea consumption and renal cell carcinoma risk in ten case-control studies using adjusted data (RR=1.08, 95% CI 0.84-1.40). Furthermore, there was no significant association in two cohort studies using adjusted data (RR=0.95, 95% CI 0.81-1.12). Conclusion: Our findings do not support the conclusion that tea consumption is related to decreased risk of renal cell carcinoma. Further prospective cohort studies are required.

Analysis of Changes in Household Food Consumption and Expenditure in Korea (우리나라 가구의 식품소비 및 지출 변화 분석)

  • Heo, Seong-Yoon;Lee, Kyei-Im;Kim, Sang-Hyo
    • The Journal of Distribution Science
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    • v.16 no.9
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    • pp.79-99
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    • 2018
  • Purpose - Food consumption in Korea has changed in paradigm as it has grown qualitatively in the past in quantitative shortages. Consumer food consumption patterns are rapidly changing due to changes in economic, social and population conditions, scientific and technological development, climate change, and market opening. At the same time, there is a need to actively respond to these changes in terms of the food industry, market, and government policy. The purpose of this study is to examine the changes and characteristics of food consumption expenditure of Korean consumers in-depth and depth in order to provide implications for agriculture, food market and policymakers. Research design, data, and methodology - We analyzed various food consumption changes from the 1980s to 2015 through Household Income and Expenditure Survey raw data from MDIS(Microdata Integrated Service) of Statistics Korea. and conducted the age effect, generation effect, and year effect by cohort analysis. We also conducted comparisons with OECD countries on several indicators. Results - Food consumption spending was slow, and there was no significant change in home consumption, while eating out consumption increased about 20 times in 2015 compared to 1980. Income, age, residential area, number of household members showed significant changes in food consumption. According to the cohort analysis, the changes in the food consumption structure are largely due to age effect, and the year, age, and generation effects are different for each food item. Conclusions - Food consumption has a significant impact on not only the nutritional status of consumers but ultimately the public health. Therefore, they should be regarded as a strategic policy area of central government rather than a matter of size and change of food consumption expenditure.

Regression analysis of doubly censored failure time data with frailty time data with frailty

  • Kim Yang-Jin
    • Proceedings of the Korean Statistical Society Conference
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    • pp.243-248
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    • 2004
  • The timings of two successive events of interest may not be measurable, instead it may be right censored or interval censored; this data structure is called doubly censored data. In the study of HIV, two such events are the infection with HIV and the onset of AIDS. These data have been analyzed by authors under the assumption that infection time and induction time are independent. This paper investigates the regression problem when two events arc modeled to allow the presence of a possible relation between two events as well as a subject-specific effect. We derive the estimation procedure based on Goetghebeur and Ryan's (2000) piecewise exponential model and Gauss-Hermite integration is applied in the EM algorithm. Simulation studies are performed to investigate the small-sample properties and the method is applied to a set of doubly censored data from an AIDS cohort study.

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Factors affecting antibiotic prescription in dental outpatients - A nation-wide cohort study in Korea - (치과 외래 치료에서 항생제 처방에 영향을 주는 요인 - 한국 국민건강보험 표본코호트 연구 -)

  • Lee, Kyeong-Hee;Choi, Yoon-Young
    • Journal of Korean society of Dental Hygiene
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    • v.19 no.3
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    • pp.409-419
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    • 2019
  • Objectives: The purpose of this study was to analyze the factors affecting antibiotic prescription in dental outpatients. Methods: The present study was conducted using data from the National Health Insurance Service - National Sample Cohort. We analyzed prescriptions issued in the dental outpatient department in 2015, for adults over 19 years of age. Antibiotic prescription rates and mean prescription days were analyzed by sex, age, insurance type, presence of diabetes mellitus and hypertension, season in treatment, type of dental institution, and location of dental institution. Multivariate logistic regression was also performed to analyze the factors affecting antibiotic prescription in dental outpatients. Results: A total of 257,038 prescriptions were analyzed. The mean prescription days of antibiotics in dental outpatients were $3.04{\pm}1.08days$, and the prescription rate was 93.0%. Two variables (presence of diabetes mellitus and insurance type) were excluded from the multivariate logistic regression analysis model because they did not significantly affect antibiotic prescription. The possibility of antibiotic prescription was higher in men ${\geq}61years$ of age and those with hypertension. Furthermore, antibiotics were most frequently prescribed in dental clinics rather than dental hospitals, and more frequently in Busan compared to other areas (p<0.001). Conclusions: Several factors were determined to affect antibiotic prescription, and detailed guidelines for consistent antibiotic prescription are needed.