• Communications for Statistical Applications and Methods
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• 제8권3호
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• pp.815-822
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• 2001

The aim of this study is to estimate the seroconversion date of the human immunodeficiency virus(HIV) infection for the HIV infected patients in Korea. Data are collected from two cohorts. The first cohort is a group of "seroprevalent" patients who were seropositive and AIDS-free at entry. The other is a group of "seroincident" patients who were initially seronegative but later converted to HIV antibody-positive. The seroconversion dates of the seroincident cohort are available while those of the seroprevalent cohort are not. Estimation of seroconversion date is important because it can be used to calculate the incubation period of AIDS which is defined as the elapsed time between the HIV infection and the development of AIDS. In this paper, a Weibull regression model Is fitted for the seroincident cohort using information about the elapsed time since seroconversion and the CD4$^{+}$ cell count.The seroconversion dates for the seroprevalent cohort are imputed on the basis of the marker of maturity of HIV infection percent of CD4$^{+}$cell count.unt.

• Asian Pacific Journal of Cancer Prevention
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• 제14권10호
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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.

• 가정과삶의질연구
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• 제14권2호
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• pp.51-60
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• 1996

The purpose of this study is to identify the objective picture of developmental pattern of marital satisfaction of couples based on family life cycle length of marriage marriage cohort birth cohort and age of couples using data from 317 couples in urban cities. The result indicate that the U-curve of marital satisfaction is the special pattern of family life cycle while W-curve is more dominant pattern when data are analysed with length of marriage birth cohort and marriage cohort. The couples differ in their assessment of marital satisfaction through entire their life span which seems for wives to become more dissatisfied over time. The similarity of developmental pattern the spouses appears only in their birth cohort. Discussion and recommendations for future research of the marital satisfaction are suggested.

• 한국식품영양학회지
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• 제33권1호
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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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• 제40권2호
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• pp.95-101
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• 2007

Focusing on complex diseases of public health significance, strategic issues regarding the on-going Korean Genome Cohort were reviewed: target size and diseases, measurements, study design issues, and follow-up strategy of the cohort. Considering the epidemiologic characteristics of Korean population as well as strengths and drawbacks of current research environment, we tried to tailor the experience of other existing cohorts into proposals for this Korean study. Currently 100,000 individuals have been participating the new Genome Cohort in Korea. Target size of de novo collection is recommended to be set as between 300,000 to 500,000. This target size would allow acceptable power to detect genetic and environmental factors of moderate effect size and possible interactions between them. Family units and/or special subgroups are recommended to parallel main body of adult individuals to increase the overall efficiency of the study. Given that response rate to the conventional re-contact method may not be satisfactory, successful follow-up is the main key to the achievement of the Korean Genome Cohort. Access to the central database such as National Health Insurance data can provide enormous potential for near-complete case detection. Efforts to build consensus amongst scientists from broad fields and stakeholders are crucial to unleash the centralized database as well as to refine the commitment of this national project.

• Journal of Preventive Medicine and Public Health
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• 제45권5호
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• pp.323-328
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• 2012

Objectives: Economic growth and development of medical technology help to improve the average life expectancy, but the western diet and rapid conversions to poor lifestyles lead an increasing risk of major chronic diseases. Coronary heart disease mortality in Korea has been on the increase, while showing a steady decline in the other industrialized countries. An age-period-cohort analysis can help understand the trends in mortality and predict the near future. Methods: We analyzed the time trends of ischemic heart disease mortality, which is on the increase, from 1985 to 2009 using an age-period-cohort model to characterize the effects of ischemic heart disease on changes in the mortality rate over time. Results: All three effects on total ischemic heart disease mortality were statistically significant. Regarding the period effect, the mortality rate was decreased slightly in 2000 to 2004, after it had continuously increased since the late 1980s that trend was similar in both sexes. The expected age effect was noticeable, starting from the mid-60's. In addition, the age effect in women was more remarkable than that in men. Women born from the early 1900s to 1925 observed an increase in ischemic heart mortality. That cohort effect showed significance only in women. Conclusions: The future cohort effect might have a lasting impact on the risk of ischemic heart disease in women with the increasing elderly population, and a national prevention policy is need to establish management of high risk by considering the age-period-cohort effect.

• Asian Pacific Journal of Cancer Prevention
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• 제16권9호
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• pp.3951-3955
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• 2015

Background: Colorectal cancer mortality has started to decrease in several developed countries in Asia. The current study aimed to present the long-term trends in colorectal cancer mortality in Korea using joinpoint analysis and age-period-cohort modeling. Materials and Methods: The number of colorectal cancer deaths and the population for each 5-year age group were obtained from Statistics Korea for the period 1984-2013 for adults 30 years and older. Joinpoint regression analysis was conducted to determine changes in trends in age-standardized mortality rates, and age-period-cohort analysis was performed to describe trends in colorectal cancer mortality using the intrinsic estimator method. Results: In men, the age-standardized mortality rate for colorectal cancer increased from 1984 to 2003, and the mortality rates stabilized thereafter, whereas the mortality rate of colorectal cancer in women has decreased since 2004. The age-specific mortality rate of colorectal cancer increased in both men and women over time, whereas decreases in the age-specific mortality rate in younger cohorts were observed. In the age-period-cohort analysis, old age and recent period were associated with higher mortality for both men and women. The birth cohort born after 1919 showed reduced colorectal cancer mortality in both men and women. Conclusions: Our study showed a recent decreasing trend in colorectal cancer mortality in women and a stable trend in men after 2003-2004. These changes in colorectal cancer mortality may be attributed to birth cohort effects.

• 한국사회복지학
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• 제65권1호
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• pp.201-226
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• 2013

외환위기 이후 청년실업의 증가가 사회적 문제로 부각되었으나, 청년층의 노동시장 경험에 관한 연구는 제한적으로 이루어져 왔다. 본 연구에서는 노동경력을 단순한 일자리 이동과 달리 노동지위의 연속적 배열과 순서적이고 위계적인 변화과정으로 개념화하였으며, 배열분석을 활용하여 외환위기 전후 청년층의 노동경력을 노동지위의 다양한 측면에서 비교하였다. 분석 결과, 외환위기 이후 첫 일자리로의 이행기간이 장기화되고 고용형태와 사업장 규모 면에서 첫 일자리의 질적 저하가 발생하였음이 확인되었다. 또한 외환위기 이후 청년 코호트는 미취업형과 실업형, 비대기업형, 비정규직형 및 이동형 특성을 갖는 경력유형에 속할 상대적 위험률이 높았다. 이러한 결과는 전반적으로 외환위기 이후 청년층의 고용불안정성이 더 커졌으며, 내부노동시장형에 비해 외부노동시장형 경력유형이 상대적으로 증가한 것을 의미한다.

• 한국콘텐츠학회논문지
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• 제17권9호
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• pp.396-405
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• 2017

본 연구의 목적은 위계적 APC(Hierarchical Age-Period-Cohort)모형과 2006~2016년 한국복지패널자료를 활용하여 베이비부머세대를 포함한 중장년 노년층(32~76세)의 가계부채규모 결정요인을 연령(Age), 기간(Period), 코호트(Cohort)로 구분하여 분석하는데 있다. 연구 분석에 사용된 대상자는 총 86,056명이다. 연구결과에 의하면 가계부채에 영향을 미치는 요인으로 연령효과와 기간효과는 통계적으로 유의하게 나타났으나, 베이비부머세대를 포함하는 특정시기 출생연도별 코호트(Cohort)효과는 통계적으로 유의하지 않았다. 연령이 한 단위 증가하면 가계부채도 353만원 증가하였지만 가계부채 증가폭은 연령증가에 따라 점차 감소하였다. 또한 연령이외의 개인단위변수로 경제활동여부, 건강상태 등이 가계부채규모에 영향을 미치는 요인으로 작용했다. 미취업자일수록, 건강상태가 좋지 않을수록 가계부채가 증가하는 것으로 나타났다.

• Journal of Preventive Medicine and Public Health
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• 제55권3호
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• pp.253-262
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• 2022

We aimed to review the current data composition of the Korean Tuberculosis and Post-Tuberculosis Cohort, which was constructed by linking the Korean Tuberculosis Surveillance System (KNTSS; established and operated by the Korean Disease Control and Prevention Agency since 2000) and the National Health Information Database (NHID; established by the National Health Insurance Service in 2012). The following data were linked: KNTSS data pertaining to patients diagnosed with tuberculosis between 2011 and 2018, NHID data of patients with a history of tuberculosis and related diseases between 2006 and 2018, and data (obtained from the Statistics Korea database) on causes of death. Data from 300 117 tuberculosis patients (177 206 men and 122 911 women) were linked. The rate of treatment success for new cases was highest in 2015 (86.7%), with a gradual decrease thereafter. The treatment success rate for previously treated cases showed an increasing trend until 2014 (79.0%) and decreased thereafter. In total, 53 906 deaths were confirmed among tuberculosis patients included in the cohort. The Korean Tuberculosis and Post-Tuberculosis Cohort can be used to analyze different measurement variables in an integrated manner depending on the data source. Therefore, these cohort data can be used in future epidemiological studies and research on policy-effect analysis, treatment outcome analysis, and health-related behaviors such as treatment discontinuation.