• Title/Summary/Keyword: cohort studies

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A Comparative Cohort Study on the Experiences of Job Loss and Job Seeking in Korea (생애주기에 따른 실직경험 및 구직활동에 관한 비교연구)

  • Yang, Sung-Eun
    • Korean Journal of Human Ecology
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    • v.21 no.1
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    • pp.41-58
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    • 2012
  • The purpose of this study was to compare the job loss and job seeking experiences between middle-aged men and their younger cohort. Participants included 11 middle-aged unemployed men and nine younger unemployed men. The study adopted a phenomenological approach. In-depth individual interviews were carried out and the theme analysis was used to analyze the interview data. The results showed that the two cohorts experienced the macroeconomic crises, the foreign exchange crisis in 1997 and the global financial crisis in 2008, differently. Their experiences affected their attribution of the unemployment and job seeking process. They expressed ambivalence toward their family while dealing with social isolation from extrafamilial support. Most of the participants criticized government employment support policies and services.

Cancer Incidence and Mortality in Osaka, Japan: Future Trends Estimation with an Age-Period-Cohort Model

  • Utada, Mai;Ohno, Yuko;Shimizu, Sachiko;Ito, Yuri;Tsukuma, Hideaki
    • Asian Pacific Journal of Cancer Prevention
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    • v.13 no.8
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    • pp.3893-3898
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    • 2012
  • In previous studies we predicted future trends in cancer incidence for each prefecture in order to plan cancer control. Those predictions, however, did not take into account the characteristics of each prefecture. We therefore used the results of age-period-cohort analysis of incidence and mortality data of Osaka, and estimated the incidence and mortality of cancers at all sites and selected sites. The results reflect the characteristics of Osaka, which has and is expected to have large number of patients with liver cancer. We believe our results to be useful for planning and evaluating cancer control activities in Osaka. It would be worthwhile to base the estimation of cancer incidence and mortality in each prefecture on each population-based cancer registry.

Mushroom consumption and cardiometabolic health outcomes in the general population: a systematic review

  • Jee Yeon Hong;Mi Kyung Kim;Narae Yang
    • Nutrition Research and Practice
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    • v.18 no.2
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    • pp.165-179
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    • 2024
  • BACKGROUND/OBJECTIVES: Mushroom consumption, rich in diverse nutrients and bioactive compounds, is suggested as a potential significant contributor to preventing cardiometabolic diseases (CMDs). This systematic review aimed to explore the association between mushrooms and cardiometabolic health outcomes, utilizing data from prospective cohort studies and clinical trials focusing on the general population, with mushrooms themselves as a major exposure. SUBJECTS/METHODS: All original articles, published in English until July 2023, were identified through searches on PubMed, Ovid-Embase, and google scholar. Of 1,328 studies, we finally selected 5 prospective cohort studies and 4 clinical trials. RESULTS: Existing research is limited, typically consisting of 1 to 2 studies for each CMD and cardiometabolic condition. Examination of articles revealed suggestive associations in some cardiometabolic conditions including blood glucose (both fasting and postprandial), high-density lipoprotein cholesterol related indices, high-sensitivity C-reactive protein, and obesity indices (body weight, body mass index, and waist circumference). However, mushroom consumption showed no association with the mortality and morbidity of cardiovascular diseases, stroke, and type 2 diabetes, although there was a potentially beneficial connection with all cause-mortality, hyperuricemia, and metabolic syndrome. CONCLUSION: Due to the scarcity of available studies, drawing definitive conclusions is premature. Further comprehensive investigations are needed to clarify the precise nature and extent of this relationship before making conclusive recommendations for the general population.

Development of a Semi-quantitative Food Frequency Questionnaire Based on Dietary Data from the Korea National Health and Nutrition Examination Survey

  • Younjhin Ahn;Lee, Ji-Eun;Paik, Hee-Young;Lee, Hong-Kyu;Inho Jo;Kim, Kuchan m
    • Nutritional Sciences
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    • v.6 no.3
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    • pp.173-184
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    • 2003
  • Objective : This study was carried out to develop a semi-quantitative food frequency Questionnaire (SQFFQ) for estimating average dietary intake to determine the risk factor for lifestyle-related diseases in a conjoint cohort study. Design : We developed an SQFFQ for genomic epidemiological studies based on the data in the'98 Korea Health and Nutrition Examination Survey. A subset of data on informative food items was collected using the 24-hr recall method with 2,714 adults aged 40 or older living in middle-sized cities or in rural areas in Korea. The cumulative percent contribution and cumulative multiple regression coefficients of 17 nutrients (energy, fat, carbohydrate, protein, fiber, iron, potassium, sodium, calcium, phosphorus, vitamin A, retinol, $\beta$-carotene, vitamin $B_1$, vitamin $B_2$, niacin and vitamin C) of each food were computed. Results : Two hundred and forty-nine foods, which were selected based on their 0.9 cumulative percent contribution, and 254 foods, which were selected based on their 0.9 cumulative multiple regression coefficients, respectively, were grouped into 97 food groups according to their nutrient contents. Several popular Korean foods, which were missing from the list due to the seasonality of the survey, were included. The portion sizes were derived from the same data set. The SQFFQ covered 84.8 percent of the intake of 17 nutrients in the one day diet record data of our 326 cohort study subjects. Conclusions . The final list included 103 food items. The foods list in the SQFFQ described herein accounted for 84.8 percent of the average intake of 17 nutrients. Therefore, the list could be used for the assessment of the baseline dietary intakes of the conjoint cohort studies.

Cancer Risks among Welders and Occasional Welders in a National Population-Based Cohort Study: Canadian Census Health and Environmental Cohort

  • MacLeod, Jill S.;Harris, M. Anne;Tjepkema, Michael;Peters, Paul A.;Demers, Paul A.
    • Safety and Health at Work
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    • v.8 no.3
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    • pp.258-266
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    • 2017
  • Background: Welders are exposed to many known and suspected carcinogens. An excess lung cancer risk among welders is well established, but whether this is attributable to welding fumes is unclear. Excess risks of other cancers have been suggested, but not established. We investigated welding cancer risks in the population-based Canadian Census Health and Environmental Cohort. Methods: Among 1.1 million male workers, 12,845 welders were identified using Standard Occupational Classification codes and followed through retrospective linkage of 1991 Canadian Long Form Census and Canadian Cancer Registry (1992-2010) records. Hazard ratios (HRs) were calculated using Cox proportional hazards models based on estimated risks of lung cancer, mesothelioma, and nasal, brain, stomach, kidney, and bladder cancers, and ocular melanoma. Lung cancer histological subtypes and risks by industry group and for occasional welders were examined. Some analyses restricted comparisons to blue-collar workers to minimize effects of potential confounders. Results: Among welders, elevated risks were observed for lung cancer [HR: 1.16, 95% confidence interval (CI): 1.03-1.31], mesothelioma (HR: 1.78, 95% CI: 1.01-3.18), bladder cancer (HR: 1.40, 95% CI: 1.15-1.70), and kidney cancer (HR: 1.30, 95% CI: 1.01-1.67). When restricted to blue-collar workers, lung cancer and mesothelioma risks were attenuated, while bladder and kidney cancer risks increased. Conclusion: Excess risks of lung cancer and mesothelioma may be partly attributable to factors including smoking and asbestos. Welding-specific exposures may increase bladder and kidney cancer risks, and particular sources of exposure should be investigated. Studies that are able to disentangle welding effects from smoking and asbestos exposure are needed.

Power Estimation and Follow-Up Period Evaluation in Korea Radiation Effect and Epidemiology Cohort Study (원전 코호트 연구의 적정 대상규모와 검정력 추정)

  • Cho, In-Seong;Song, Min-Kyo;Choi, Yun-Hee;Li, Zhong-Min;Ahn, Yoon-Ok
    • Journal of Preventive Medicine and Public Health
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    • v.43 no.6
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    • pp.543-548
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    • 2010
  • 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 nonexposure 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.

Association of Alzheimer's Disease with the Risk of Developing Epilepsy: a 10-Year Nationwide Cohort Study

  • Lyou, Hyun Ji;Seo, Kwon-Duk;Lee, Ji Eun;Pak, Hae Yong;Lee, Jun Hong
    • Dementia and Neurocognitive Disorders
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    • v.17 no.4
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    • pp.156-162
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    • 2018
  • Background and Purpose: Previous studies have reported conflicting results about the prevalence of seizures in Alzheimer's disease (AD). There are few epidemiological studies on this topic in Asia. Thus, the objective of this study was to examine demographic and clinical characteristics as well as incidence for seizures in AD patients compared to non-AD patients in a prospective, longitudinal, community-based cohort with a long follow-up. Methods: Data were collected from National Health Insurance Service-National Elderly Cohort (NHIS-elderly) Database to define patients with AD from 2004-2006 using Korean Classification Diseases codes G30 and F00. We performed a 1:5 case-control propensity score matching based on age, sex, and household income. We conducted Cox proportional hazards regression analysis to estimate the risk of epilepsy in AD patients. Results: In the cohort study, patients with AD had higher risk for epilepsy than those without AD, with hazard ratio of 2.773 (95% confidence interval [CI], 2.515-3.057). This study also showed that male gender and comorbidities such as hypertension, hyperlipidemia, diabetes, and chronic kidney disease increased the risk of developing epilepsy. Patients with AD had 1.527 (95% CI, 1.375-1.695) times higher mortality rate than those in the control group. Conclusions: AD patients have significantly higher risk of developing epilepsy than non-AD patients.

Study Design and Outcomes of Korean Obstructive Lung Disease (KOLD) Cohort Study

  • Park, Tai Sun;Lee, Jae Seung;Seo, Joon Beom;Hong, Yoonki;Yoo, Jung-Wan;Kang, Byung Ju;Lee, Sei Won;Oh, Yeon-Mok;Lee, Sang-Do
    • Tuberculosis and Respiratory Diseases
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    • v.76 no.4
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    • pp.169-174
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    • 2014
  • Background: The Korean Obstructive Lung Disease (KOLD) Cohort Study is a prospective longitudinal study of patients with chronic obstructive pulmonary disease (COPD), asthma, or other unclassified obstructive lung diseases. It was designed to develop new classification models and biomarkers that predict clinically relevant outcomes for patients with obstructive lung diseases. Methods: Patients over 18 years old who have chronic respiratory symptoms and airflow limitations or bronchial hyper-responsiveness were enrolled at 17 centers in South Korea. After a baseline visit, the subjects were followed up every 3 months for various assessments. Results: From June 2005 to October 2013, a total of 477 subjects (433 [91%] males; 381 [80%] diagnosed with COPD) were enrolled. Analyses of the KOLD Cohort Study identified distinct phenotypes in patients with COPD, and predictors of therapeutic responses and exacerbations as well as the factors related to pulmonary hypertension in COPD. In addition, several genotypes were associated with radiological phenotypes and therapeutic responses among Korean COPD patients. Conclusion: The KOLD Cohort Study is one of the leading long-term prospective longitudinal studies investigating heterogeneity of the COPD and is expected to provide new insights for pathogenesis and the long-term progression of COPD.

Developmental Trajectories of Externalizing Problems Perceived by Teachers in Preschool Settings : A Short Term Longitudinal Study with Applied Latent Growth Curve Modeling (교사가 지각한 유아기 외현화 문제행동의 발달 경로 - 잠재성장곡선모형을 적용한 단기종단연구 -)

  • Kang, Ji-Hyeon;Oh, Kyung-Ja
    • Korean Journal of Child Studies
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    • v.30 no.4
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    • pp.69-85
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    • 2009
  • The purpose of this study was to identify developmental trajectories of externalizing problems in preschoolers and to investigate dimensions of temperament and parental behaviors associated with trajectory groups. Subjects were 180 3- to 5-year-old preschoolers (96 males, 84 females) in the metropolitan area of Seoul. They were assessed three times at 5 month intervals over a one year period. Teachers reported on children's behavior problems, and parents reported on children's temperaments. Latent Growth Curve Modeling Analysis with cohort sequential design revealed externalizing behaviors gradually decreased between 3 and 6. At the 6-year-old level externalizing behaviors were associated with high novelty seeking temperament. The results were discussed in terms of the importance of longitudinal research in developmental psychopathology.

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Association Between Green Tea Consumption and Lung Cancer Risk

  • Lee, Andy H.;Liang, Wenbin;Hirayama, Fumi;Binns, Colin W.
    • Journal of Preventive Medicine and Public Health
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    • v.43 no.4
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    • pp.366-367
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    • 2010
  • Green tea is a popular beverage and its health benefits are well known. However, inconsistent results have been reported in observational studies concerning the association between green tea consumption and the lung cancer risk. In this commentary, several methodological issues underlying the measurement of tea exposure are highlighted. The recommendations should be useful for designing and planning prospective cohort studies to ascertain the protective effect of green tea against lung cancer.