• Title/Summary/Keyword: Proportional Hazard Model

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A study on the Factors Affecting Job Separation by Middle and Old aged Self-Employed using KLoSA Panel (고령화연구조사(KLoSA) 패널을 활용한 중고령 자영업자의 일자리 이탈 요인에 관한 연구)

  • Choi, Whayoung
    • Journal of vocational education research
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    • v.37 no.1
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    • pp.119-138
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    • 2018
  • The purpose of this study was to analyze the factors influencing of separation and the time of separation for middle and old aged self-employed workers. The cox proportional hazards model was used in the first survey of KLoSA, 684 persons who were over 40 years old in 2006, using data up to the 5th period of 2014. The main findings of this study are as follows. First, the average duration of job for middle and old aged self-employed workers in 2005 was 15.5years. Of the total 684 workers, 214(31.3%) person was found to have lost their job during survey period. Second, gender, age at start up, and education level have significant effects on job separation of them. When women, when they were older at start up, when they were graduate the university or higher, increased their risk of leaving their businesses. Third, in the characteristic of their work, the type of job and job satisfaction were found to affect to job desertion. When people are engaged in accommodation and food business rather than agriculture and forestry fishery, when the satisfaction of the work is lower, the risk was high. Based on these conlusions, the following implications are suggested. First, it is necessary to establish a support strategy for female middle-aged and old self-employed and older workers who start their own business after their 60s. Second, it is necessary to support them to enter into various fields by utilizing their own aptitude and experience rather than establishing them in industries with low entry barriers. Third, it is necessary to develop policies to help improve job satisfaction in the working environment. In particular, it is necessary to ensure that high educated self-employed workers are satisfied with various compensations by self-employed.

Prediction of Life-expectancy for Patients with Hepatocellular Carcinoma Based on Prognostic Factors (간암 환자에서 예후인자를 통한 생존기간의 예측)

  • Yeom, Chang-Hwan;Shim, Jae-Yong;Lee, Hye-Ree;Hong, Young-Sun
    • Journal of Hospice and Palliative Care
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    • v.1 no.1
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    • pp.30-38
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    • 1998
  • Background : Hepatocellular carcinomoma is the 3rd most common malignancy and the 2nd most common cause of death in Korea. The prediction of life-expectancy in terminal cancer patients is a major problem for patients, families, and physicians. We would like to investigate the prognostic factors of hepatocellular carcinoma, and therefore contribute to the prediction of the survival time of patients with hepatocellular carcinoma. Methods : A total of 91 patients(male 73, female 18) with hepatocellular carcinoma who were admitted to the hospital between January and lune 1995 were entered into the study, and data were collected prospectively on 28 clinical parameters through medical obligation record. We surveyed an obligation and local district office records, and confirmed the surivival of patients till July, 1996. Using Cox-proportional hazard model, give the significant variables related to survival. These determined prognostic factors. Life regressional analysis was used, there were calculated predicted survival day based on combinations of the significant prognostic factors. Results : 1) Out of 91 patients, 73 were male, and 18 were female. The mean age was 56.7±10.6 ears. During the study, except for 16 patients who could not follow up, out of 75 patients, the number of deaths was 57(76%) and the number of survivals was 18(24%). 2) Out of the 28 clinical parameters, the prognostic factors related to reduced survival rate were prothrombin time<40%(relative risk:10.8), weight loss(RR:4.4), past history of hypertension (RR:3.2), ascites(RR:2.8), hypocalcemia(RR:2.5)(P<0.001). 3) Out of five factors, the survival day is 1.7 in all of five, 4.210.0 in four, 10.441.9 in three, 29.5118.1 in two, 124.0296.6 in one, 724.0 in none. Conclusion : In hepatocellular carcinoma we found that the prognostic factors related to reduce survival rate were prolonged prothrombin time(<40%), weight loss, past history of hypertension, ascites, and hypocalcemia(<8.7mg/dl). The five prognostic factors enabled the prediction of life-expectancy in patients with hepatocellular carcinoma and may assist in managing patients with hepatocellular carcinomal.

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Risk Factors Related to Development of Delirium in Hospice Patients (호스피스 병동의 암환자에서 섬망 발생 위험 요인)

  • Ko, Hae Jin;Youn, Chang Ho;Chung, Seung Eun;Kim, A Sol;Kim, Hyo Min
    • Journal of Hospice and Palliative Care
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    • v.17 no.3
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    • pp.170-178
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    • 2014
  • Purpose: Delirium is a common and serious neuropsychiatric complication among terminally ill cancer patients. We investigated risk factors related to the development of delirium among hospice care patients. Methods: Between May 2011 and September 2012, we included patients who were mentally alert and had no psychiatric disease or drug addiction at the hospice ward of two local hospitals. Among them, participants who had been diagnosed with delirium by two doctors according to the DSM-IV (Diagnostic and Statistical Manual of Mental Disorders-4th edition) criteria were grouped as Delirium Group. We analyzed results of psychometric and other laboratory tests performed at the time of patient's admission - psychometric tests included cognitive function (mini-mental status examination, MMSE), depression (Beck Depression Inventory, BDI), anxiety, and insomnia (Insomnia Severity Index, ISI). Logistic regression analysis was used to compare delirium and the related factors. Cox's proportional hazard model was performed using significant factors of logistic regression analysis. Results: Of the 96 patients who met the inclusion criteria, 41 (42.7%) developed delirium. According to the logistic regression analysis, primary cancer site, cognitive impairment (MMSE < 24), depression (BDI16), and insomnia (ISI15) were significant factors related to delirium. Among the four factors, depression (OR 5.130; 95% CI, 2.009~13.097) and cognitive impairment (OR 5.130; 95% CI, 2.009~13.097) were found significant using Cox's proportional hazard model. Conclusion: The development of delirium was significantly related to depression and cognitive impairment among patients receiving hospice care. It is necessary to carefully monitor depression and cognitive function in hospice care.

Predictors of breast-feeding discontinuation in some followed-up hospital-delivered mothers (추적조사된 대구시내 일부 병원분만 산모에서 모유수유중단 예측변수)

  • Lee, Choong-Won;Lee, Moo-Sik;Park, Jong-Won;Lee, Mi-Young;Kang, Mi-Joung;Shin, Dong-Hoon;Lee, Se-Youp
    • Journal of Preventive Medicine and Public Health
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    • v.28 no.4 s.51
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    • pp.845-862
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    • 1995
  • We followed prospectively some hospital-delivered mothers to identify characteristics of those not initiated breast-feeding and predictors of breast-feeding discontinuation in monthly telephone interviews. Recruits were composed of 482 mothers who delivered their babies at one university hospital and one OB/GYN clinic in September to November 1991. Breast-feeding discontinuation was defined as switch to 100% formula lasting more than one week regardless of solid foods. Average age of the study subjects was 27.3 years of age(standard deviation 3.2). Multiple logistic regression analysis indicated native place, occupation, method of delivery and method of feeding considered to be better for maternal health were statistically significant(p<0.1) between initiators and non-initiators of breast feeding. In starting cohort(N=242) of those initiated breast-feeding, that median of breast-feeding discontinuation were 5 months and 25th and 75th percentiles were 3 and 9 months respectively. In Cox's proportional hazard model, mothers with 1013 years of education were 2.63 times (95% confidence interval, CI 1.504.60) more likely to discontinue than those with less than 9 years of education and those with more than 13 years of education were 3.55 time (95% CI 1.996.33). Compared with house wife, mothers with part-time jobs were 1.99 times (95% CI 0.864.57) more likely to discontinue and those with employed full-time were 1.55 times (95% CI 0.962.51). These results suggest that the predictors of initiation and discontinuation of breast-feeding may be different and different target populations should be selected to promote initiation and to prevent discontinuation of breast-feeding according to the period after birth.

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Impact of Social Activities on Healthy Life Expectancy in Korean Older Adults: 13-Year Survival Analysis Focusing on Gender Comparison (한국 노인의 사회활동이 건강수명에 미치는 영향에 대한 생존분석: 성별 비교를 중심으로 한 13년간 분석)

  • Yang, Seungmin;Choi, Jae-Sung
    • 한국노년학
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    • v.41 no.4
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    • pp.547-566
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    • 2021
  • The purpose of this study is to analyze the effect of social activities on healthy life expectancy (HLE) by gender difference. HLE implies an estimate of how long an individual can expect to live in full health or without disease and/or disability. Morbidity, mortality, and functional health status usually have been known as key variables. Many researchers have tried to investigate factors affecting HLE in countries level by performing comparative analyses. In micro level, there have been some studies about social factors affecting HLE in individual level. However, few studies are found focusing on the relationship between HLE and social activities. This study anlayzes 4,029 over 65 years of age from the first wave (2006) to the seventh wave (2018) of the Korean Longitudinal Study of Ageing (KLoSA), which is a national panel data collected by Korea Employment Information Service. The data has been collected as a part of social and economic policies planning for Korean government. HLE was measured by life period without disease or disability. One of findings is that male older adults (76.9 yrs) show higher HLE in comparing to female group (75.3 yrs). Female group appeared to be more likely to have higher incidence rate and disorders. Another finding indicates that age, number of chronic diseases, and subjective health status affect HLE of both groups. Finally, regarding social activities, religion affiliated activities appear to significantly affect HLE of both groups. In case of male older adults, alumni or hometown gathering also appeared another activities affecting HLE. This study indicates that the effect of social activities types on HLE among older adults appears differently by gender. Further, unlikely of longer life expectancy among female older adults as known, HLE shows a reverse estimate, longer healthy life expectancy among male older adults. This finding may imply that later life of female older adults shows lower quality of life in comparing to that of male group, even if female life expectancy has been higher. This study encourages to develop more social activity programs for older adults in community level. Specifically, more attention is required to planning for programs targeting female older adults.

Crash Clearance Time Analysis of Korean Freeway Systems using a Cox Model (Cox 모형을 활용한 고속도로 사고 처리시간 영향인자 분석)

  • Chung, Younshik;Kim, Seon Jung
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.37 no.6
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    • pp.1017-1023
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    • 2017
  • Duration induced by freeway crashes has a critical influence on traffic congestion. In general, crash duration composes detection and verification, response, and clearance time. Of these, the crash clearance time determined by a crash clearance team has attracted considerable attention in the freeway congestion management since the interest of the first two time stages faded away with increasing ubiquitous mobile phone users. The objective of this study is to identify the critical factors that affect freeway crash clearance time using a Cox's proportional hazard model. In total, 6,870 crash duration data collected from 30 major Korean freeways in 2013 were used. As a result, it was found that crashes during the night, with trailer or larger size truck, and in tunnel section contribute to increasing clearance time. Crashes associated with fatality, completed damage of crashed vehicle (s), and vehicles' fire or rollover after crash also lead to increasing clearance time. Additionally, an increase in the number of vehicles involved resulted in longer clearance time. On the other hand, crashes in the vicinity of tollgate, by passenger car, during spring, on flat section, and of car-facility type had longer clearance time. On the basis of the results, this paper suggested some strategic plans and mitigation measures to reduce crash clearance time on Korean freeway systems.

Fatty Acid Synthesis Pathway Genetic Variants and Clinical Outcome of Non-Small Cell Lung Cancer Patients after Surgery

  • Jin, Xin;Zhang, Ke-Jin;Guo, Xu;Myers, Ronald;Ye, Zhong;Zhang, Zhi-Pei;Li, Xiao-Fei;Yang, Hu-Shan;Xing, Jin-Liang
    • Asian Pacific Journal of Cancer Prevention
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    • v.15 no.17
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    • pp.7097-7103
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    • 2014
  • Over-expression of de novo lipogenesis (DNL) genes is associated with the prognosis of various types of cancers. However, the effects of single nucleotide polymorphisms (SNPs) in these genes on recurrence and survival of non-small cell lung cancer (NSCLC) patients after surgery are still unknown. In this study, a total of 500 NSCLC patients who underwent surgery treatment were included. Eight SNPs in 3 genes (ACACA, FASN and ACLY) of the DNL pathway were examined using the Sequenom iPLEX genotyping system. Multivariate Cox proportional hazards regression and Kaplan-Meier curves were used to analyze the association of SNPs with patient survival and tumour recurrence. We found that two SNPs in the FASN gene were significantly associated with the recurrence of NSCLC. SNP rs4246444 had a significant association with lung cancer recurrence under additive model (hazard ratio [HR], 0.82; 95% confidence interval [95%CI], 0.67-1.00; p=0.05). Under the dominant model, rs4485435 exhibited a significant association with recurrence (HR, 0.75; 95%CI, 0.56-1.01; p=0.05). Additionally, SNP rs9912300 in ACLY gene was significantly associated with overall survival in lung cancer patients (HR, 1.41; 95%CI, 1.02-1.94, p=0.04) under the dominant model. Further cumulative effect analysis showed moderate dose-dependent effects of unfavorable SNPs on both survival and recurrence. Our data suggest that the SNPs in DNL genes may serve as independent prognostic markers for NSCLC patients after surgery.

Survival Time and Molecular Subtypes of Breast Cancer after Radiotherapy in Thailand

  • Kongsiang, Apichat;Tangvoraphonkchai, Vorachai;Jirapornkul, Chananya;Promthet, Supannee;Kamsa-ard, Siriporn;Suwanrungruang, Krittika
    • Asian Pacific Journal of Cancer Prevention
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    • v.15 no.23
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    • pp.10505-10508
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    • 2015
  • Background: Breast cancer is an important cause of death among women. One way of classifying different forms of breast cancer is by molecular features, usually in terms of the four subtypes: luminal A, luminal B, HER2-enriched, and triple negative. Objectives: This study aimed to investigate the association between molecular subtypes and survival among breast cancer patients treated with radiotherapy. Materials and Methods: A retrospective cohort study was conducted. The subjects were 272 breast cancer patients who had received treatment in the radiotherapy unit at Srinagarind Hospital, Thailand, between 1 January, 1999, and 31 May, 2009. The end of the study was 1 June, 2014. Overall survival was defined as the time elapsing between initial registration at the radiotherapy unit and death or the end of the study. Survival curves were estimated by the Kaplan-Meier method, and a multivariate analysis was performed using Cox's proportional hazard regression model. Results: The patient mean age was 47.5±10.4 at the time of diagnosis. Of the 272 patients, 146 (53.7%) were classified as luminal A, 12 (4.4%) as luminal B, 30 (11.0%) as HER2-enriched, and 84 (30.9%) as triple negative. The overall survival rates at 1, 3 and 5 years were 87.1%, 68.4% and 59.2%, respectively. According to molecular subtypes, HER2-enriched patients had the lowest 5-year survival rate (30.0 %, 95%CI: 15.02-46.55). The median follow-up time was 8.37 years. In the Cox model analysis a higher risk of death was found for patients with HER2-enriched (HRadj=3.34, 95%CI:1.96-5.67), triple negative (HRadj=2.17, 95%CI: 1.44-3.27), and stage IIlB (HRadj=2.20, 95%CI: 1.16-4.17) cancers. Conclusions: The worst survival rates were among patients classified as HER2-enriched, triple negative and at stage IIIB. Early detection and an advanced treatment modality are needed to help these patients.

Analysis of Survivability for Combatants during Offensive Operations at the Tactical Level (전술제대 공격작전간 전투원 생존성에 관한 연구)

  • Kim, Jaeoh;Cho, HyungJun;Kim, GakGyu
    • The Korean Journal of Applied Statistics
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    • v.28 no.5
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    • pp.921-932
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    • 2015
  • This study analyzed military personnel survivability in regards to offensive operations according to the scientific military training data of a reinforced infantry battalion. Scientific battle training was conducted at the Korea Combat Training Center (KCTC) training facility and utilized scientific military training equipment that included MILES and the main exercise control system. The training audience freely engaged an OPFOR who is an expert at tactics and weapon systems. It provides a statistical analysis of data in regards to state-of-the-art military training because the scientific battle training system saves and utilizes all training zone data for analysis and after action review as well as offers training control during the training period. The methodologies used the Cox PH modeling (which does not require parametric distribution assumptions) and decision tree modeling for survival data such as CART, GUIDE, and CTREE for richer and easier interpretation. The variables that violate the PH assumption were stratified and analyzed. Since the Cox PH model result was not easy to interpret the period of service, additional interpretation was attempted through univariate local regression. CART, GUIDE, and CTREE formed different tree models which allow for various interpretations.

Smoking and Colorectal Cancer Risk in the Korean Elderly (노인 인구에서 흡연과 대장암 발생 위험간의 관련성)

  • Kim, Hwa-Jung;Lee, Seung-Mi;Choi, Nam-Kyong;Kim, Seon-Ha;Song, Hong-Ji;Cho, Young-Kyun;Park, Byung-Joo
    • Journal of Preventive Medicine and Public Health
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    • v.39 no.2
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    • pp.123-129
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    • 2006
  • Objectives : The incidence of colorectal cancer increased greatly among the elderly in Korea, but the relationship between smoking and colon cancer remains controversial. Few studies have targeted Asian elderly people. We analyzed the smoking status, the amount smoked, and the smoking duration as risk factors of colorectal cancer to determine their association and causality. Methods: The cohort members (n=14, 103) consisted of 4,694 males and 9,409 females, and they were derived from the Korea Elderly Phamacepidemilogic Cohort (KEPEC), which was a population-based dynamic cohort. They were aged 65 years or more and they lived in Busan Metropolitan City between from 1993-1998; they were beneficiaries of the Korean Medical Insurance Corporation (KMIC). The baseline information was surveyed by a self-administered mailed questionnaire; after 8.7 person-years of mean follow up period, 100 cases of colorectal cancer occurred. The adjusted relative ratio (aRR) of smoking status, the smoking amount and the smoking duration were calculated from the Cox's proportional hazard model with the never-smokers as a reference group and the Cox model controlled for age, gender, precancerous lesions of CRC, medication history of NSAIDs & antibiotics, the alcohol drinking status and BMI. Results : Compared with the never smokers, the aRRs were 2.03 (95% CI=1.02-4.03) and 1.36 (95% CI=0.80-2.32) for the ex-smokers and current smokers, respectively. Statistical significant trends were not observed for the dose-relationship among the elderly, either for the mean daily amount smoked (p for trend=0.28) or for the total amount (p for trend=0.15). Still, the aRRs were 1.51 (95% CI=0.97-2.34) for the elderly who smoked less than 40 years and 2.35 (95% CI=1.16-4.74) for the elderly who had 40 years or more of smoking (p for trend=0.06). Smokers who started smoking before the age 20 had an increased aRR of 2.15 (95% CI=1.17-3.93) compared to the never smokers. Conclusions : After controlling for age, gender, precancerous lesion of CRC, medication history of NSAIDs & antibiotics, the alcohol drinking status and BMI, smoking increases the risk of colorectal cancer among elderly people. The age when starting smoking is also important.