• Human Ecology Research
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• v.57 no.1
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• pp.51-71
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• 2019

This study analyzed the poverty rate by poverty dimension, correlation between multidimensional poverty, variables that affected the number of poverty dimension and the probability of the poor or not. The sample consisted of 6,361 elderly households (1,561 baby boom birth cohort, 1,793 post-liberation birth cohort, 3,007 Japanese colonial period birth cohort) taken from the $12^{th}$ Korean Welfare Panel Study. First, the highest poverty rate among the baby boom birth cohort was 62.8% of employment poverty. The highest rate among the post-liberation birth cohort and Japanese colonial period birth cohort, was 82.5%, 92.3% of health poverty, respectively. Second, the highest coefficient in the baby boom birth cohort was .354 for asset poverty and relation poverty. In the remaining two cohorts, the coefficient for asset poverty and relation poverty was the highest at .268, .284, respectively. Third, the average number of poverty dimensions was 2.318 of the baby boom birth cohort, 2.921 of the post-liberation birth cohort, 3.564 of the poverty in the Japanese colonial period birth cohort. Also, the poverty rate for each cohort was 20.179%, 28.779%, and 50.083%, respectively. Fourth, the significant variables in all cohorts were gender, education, marital status, residence, and equalized ordinary income for the multiple regression analysis on the number of poverty dimensions. Additionally, age of the post-liberation birth cohort was significant, age and family numbers of the Japanese colonial period birth cohort were significant. Significant variables in logistic analysis on the probability of poverty or not were the same as those of regression analysis.

• Journal of Preventive Medicine and Public Health
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• v.53 no.3
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• pp.198-204
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• 2020

Objectives: This study aimed to analyze the mortality of heart disease (HD), ischemic heart disease (IHD), and cerebrovascular disease (CeVD) through an age-period-cohort (APC) analysis. Methods: We used data on mortality due to cardiovascular disease from 1995 to 2018 in Japan, as determined by Vital Statistics. Age groups from 0 years to 99 years were defined by 5-year increments, and cohorts were defined for each age group of each year with a 1-year shift. We used Bayesian APC analysis to decompose the changes in the diseases' mortality rates into age, period, and cohort effects. Results: The period effects for all diseases decreased during the analyzed periods for both men and women. The cohort effects for men increased substantially in cohorts born from around 1940 to the 1970s for all types of cardiovascular diseases. The cohort effects of HD decreased in the cohorts born in the 1970s or later for both men and women. Regarding IHD and CeVD, either a non-increase or decrease of cohort effects was confirmed for cohorts born in the 1970s or later for men, but the effects for women showed a continuously increasing trend in the cohorts born in the 1960s or later. Conclusions: The cohort effects for IHD and CeVD showed increasing trends in younger generations of women. This suggests that preventive approaches against cardiovascular diseases are needed, particularly for women.

• The Korean Journal of Food And Nutrition
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• v.33 no.1
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• pp.98-104
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• 2020

The purpose of this study was to analyze a cohort, age, and time effects on sodium and sodium-calorie intake using the 2007~2017 Korea National Health and Nutrition Examination Survey (KNHANES). For analysis, we have constructed cohort panel data that combine KNHANES data in a time series. The age effect gradually increased from age 45~49 and then decreased afterwards. The time effect showed an increase in average sodium intake until 2010 followed by a subsequent decrease. The cohort effect showed that the sodium intake was the highest for the War of Liberation 1946~1953, and that the younger the latter, the lower the sodium intake. According to a cohort analysis, the younger the generation, the lower the sodium intake compared to the calorie intake, according to the baby boomers. Based on the results of this study, efforts should be made to educate and promote the dieting and providing low-salt meals to reduce sodium intake by generation. An analysis of the health hazards including sodium by generation and age is thought to enable the establishment relevant policies.

• Journal of Preventive Medicine and Public Health
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• v.53 no.6
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• pp.409-418
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• 2020

Objectives: This study conducted an age-period-cohort (APC) analysis of trends in healthy lifestyle behaviors in Japan. Methods: We used National Health and Nutrition Survey data on salt intake and prevalence of smoking, drinking, and physical activity between 1995 and 2018 in Japan. Age groups were defined from 20 years to 69 years old in 10-year increments. Cohorts were defined for each age group of each year with a 1-year shift, and cohorts born in 1926-1935 (first cohort) until 1989-1998 (last cohort) were examined. We conducted a Bayesian APC analysis, calculating estimated values for each behavior by age group, period, and cohort. Results: Estimated salt intake decreased from cohorts born in the 1930s to the 1960s, but increased thereafter in both genders, and the magnitude of increase was larger for men. Estimated smoking prevalence increased in the cohorts starting from the 1930s for men and the 1940s for women, and then decreased starting in the cohorts born in the 1970s for both genders. Although estimated drinking prevalence decreased starting in the cohorts born in approximately 1960 for men, for women it increased until the cohorts born in approximately 1970. Estimated physical activity prevalence decreased starting in the cohorts born in the 1940s in both genders, but the magnitude of decrease was larger for women. Conclusions: Trends in cohort effects differed by gender, which might be related to changes in the social environment for women. Improvements in dietary and exercise habits are required in more recently born cohorts of both genders.

• Korean Medical Education Review
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• v.25 no.2
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• pp.102-108
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• 2023

This study shares details on the operating process and results of the cohort of students and graduates that was designed and implemented at Konyang University College of Medicine in Daejeon and discusses future directions for cohort establishment and improvement. First, Konyang University College of Medicine established the necessity and defined the purpose of cohort design and implementation. A task force was formed to establish guidelines for analysis targets, procedures, reports, and data management, and cohort operation was classified as a quality control activity. Data were collected through surveys of current students and graduates, and data generated during the curriculum were collected, analyzed, and reported every 2 years. The cohort data collection and analysis methods are designed by the Department of Medical Education, and data collection is carried out by the administrative team and each committee. Data management and analysis are handled by the Center for Medical Education Support, and analysis and reporting are conducted by the Department of Medical Education. Various members of the medical school are working to collect and analyze data, report findings, provide feedback, and improve. In the future, we plan to advance database computerization and work toward more effective data analysis. Cohort operation should not be another burden for medical schools; instead, it is hoped that operating cohorts will be a meaningful activity to increase the effectiveness of medical education and help in the operation and policy decisions of medical schools.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.18
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• pp.8589-8594
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• 2016

Background: Liver cancer is one of the most common causes of death in the world. In Korea, hepatitis B virus (HBV) is a major risk factor for liver cancer but infection rates have been declining since the implementation of the national vaccination program. In this study, we examined the secular trends in liver cancer mortality to distinguish the effects of age, time period, and birth cohort. Materials and Methods: Data for the annual number of liver cancer deaths in Korean adults (30 years and older) were obtained from the Korean Statistical Information Service for the period from 1984-2013. Joinpoint regression analysis was used to study the shapes of and to detect the changes in mortality trends. Also, an age-period-cohort model was designed to study the effect of each age, period, and birth cohort on liver cancer mortality. Results: For both men and women, the age-standardized mortality rate for liver cancer increased from 1984 to 1993 and decreased thereafter. The highest liver cancer mortality rate has shifted to an older age group in recent years. Within the same birth cohort group, the mortality rate of older age groups has been higher than in the younger age groups. Age-period-cohort analysis showed an association with a high mortality rate in the older age group and in recent years, whereas a decreasing mortality rate were observed in the younger birth cohort. Conclusions: This study confirmed a decreasing trend in liver cancer mortality among Korean men and women after 1993. The trends in mortality rate may be mainly attributed to cohort effects.

• Health Policy and Management
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• v.28 no.4
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• pp.378-391
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• 2018

Background: People who were born in different years, that is, different birth cohorts, grow in varying socio-historical and dynamic contexts, which result in differences in social dispositions and physical abilities. Methods: This study used age-period-cohort analysis method to establish explanatory models on healthcare expenditure in Korea reflecting birth cohort factor using intrinsic estimator. Based on these models, we tried to investigate the effects of ageing population on future healthcare expenditure through simulation by scenarios. Results: Coefficient of cohort effect was not as high as that of age effect, but greater than that of period effect. The cohort effect can be interpreted to show 'healthy ageing' phenomenon. Healthy ageing effect shows annual average decrease of -1.74% to 1.57% in healthcare expenditure. Controlling age, period, and birth cohort effects, pure demographic effect of population ageing due to increase in life expectancy shows annual average increase of 1.61%-1.80% in healthcare expenditure. Conclusion: First, since the influence of population factor itself on healthcare expenditure increase is not as big as expected. Second, 'healthy ageing effect' suggests that there is a need of paradigm shift to prevention centered-healthcare services. Third, forecasting of health expenditure needs to reflect social change factors by considering birth cohort effect.

• Korean Medical Education Review
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• v.25 no.2
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• pp.119-125
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• 2023

Pusan National University School of Medicine (PNUSOM) began analyzing the cohort of pre-medical students admitted in 2015 and has been conducting purposeful analyses for the past 3 years. The aim of this paper is to introduce the process of cohort establishment, cohort composition, and the utilization of cohort analysis results. PNUSOM did not initially form a cohort with a purpose or through a systematic process, but was able to collect longitudinal data on students through the establishment of a Medical Education Information System and an organization that supports medical education. Cohort construction at our university is different in terms of a clear orientation toward research questions, flexibility in cohort composition, and subsequent guideline supplementation. We investigated the relevance of admission factors, performance improvements, satisfaction with the educational environment, and promotion and failure rate in undergraduate students, as well as performance levels and career paths in graduates. The results were presented to the Admissions Committee, Curriculum Committee, Learning Outcomes Committee, and Student Guidance Committee to be used as a basis for innovations and improvements in education. Since cohort studies require long-term efforts, it is necessary to ensure the efficiency of data collection for graduate cohorts, as well as the validity and ethics of the study.

• Journal of Preventive Medicine and Public Health
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• v.40 no.2
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• pp.108-113
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• 2007

When conducting large-scale cohort studies, numerous statistical issues arise from the range of study design, data collection, data analysis and interpretation. In genomic cohort studies, these statistical problems become more complicated, which need to be carefully dealt with. Rapid technical advances in genomic studies produce enormous amount of data to be analyzed and traditional statistical methods are no longer sufficient to handle these data. In this paper, we reviewed several important statistical issues that occur frequently in large-scale genomic cohort studies, including measurement error and its relevant correction methods, cost-efficient design strategy for main cohort and validation studies, inflated Type I error, gene-gene and gene-environment interaction and time-varying hazard ratios. It is very important to employ appropriate statistical methods in order to make the best use of valuable cohort data and produce valid and reliable study results.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.10
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• pp.5891-5893
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• 2013

Incidence/mortality of liver cancer follow logistic curves because there is a limit reflecting the prevalence of hepatitis virus carriers in the cohort. The author fitted logistic curves to incidence/mortality data covering the nine five-year cohorts born in 1911-1955 of both sexes. Goodness-of-fit of logistic curves was sufficiently precise to be used for future predictions. Younger cohorts born in 1936 or later were predicted to show constant decline in incidence/mortality in the future. The male cohort born in 1931-35 showed an elevated incidence/mortality of liver cancer early in their lives supporting the previous claim that this particular cohort had suffered massive HCV infection due to nation-wide drug abuse in the 1950s. Declining case-fatality observed in younger cohorts suggested improved treatment of liver cancer. This study demonstrated that incidence/mortality of liver cancer follow logistic curves and fitted logistic formulae can be used for future prediction. Given the predicted decline of incidence/mortality in younger cohorts, liver cancer is likely to be lost to history in the not-so-distant future.