• 제목/요약/키워드: cox's proportional hazard model

검색결과 112건 처리시간 0.027초

축산 질병 보도가 소, 돼지고기 구입에 미치는 영향에 관한 연구 (A Study on the Effects of Livestock Disease News on the Purchase of Beef and Pork)

  • 신정섭
    • 한국산학기술학회논문지
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    • 제20권10호
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    • pp.425-432
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    • 2019
  • 본 연구는 한국언론진흥재단 BIGKinds를 통해 수집한 구제역 등의 축산 질병 관련 보도가 소비자의 육류소비에 미치는 영향요인들을 알아보기 위하여 생존 분석을 이용하여 분석하였다. 소비자 구매자료는 농촌진흥청의 농식품 소비자 패널조사 자료를 이용하였으며, 생존시간에 대한 분석결과 국내산 소고기와 돼지고기, 수입산 소고기와 돼지고기 모두에서 FMD(구제역) 보도가 유의한 영향을 미치며, FMD(구제역) 관련 보도로 인해 첫 구매율이 감소한 것으로 나타났다. 시간 의존 Cox 비례 해저드 모형을 이용하여 세부적으로 분석한 결과 모든 모형은 5% 유의수준에서 유의한 것으로 분석되었다. 각 모형에서 공통적으로 유의한 것으로 분석된 것은 FMD 관련 보도 건수로 나타났다. 2010년 국내산과 수입산 돼지고기의 Haz. Ratio는 5% 유의수준에서 0.999로 나타나 FMD 관련 보도가 1건 증가할 때마다 첫 구매율은 0.999배 감소한 것으로 분석되었다. 반면 2015년 돼지고기의 Haz. Ratio는 2010년과는 다르게 1.001로 나타나 오히려 첫 구매율이 증가한 것으로 분석되었다. 소고기의 경우에도 돼지고기와 비슷한 결과가 나타났다. 본 연구는 소비자의 육류소비에 질병 관련 보도가 첫 구매에 어떠한 영향을 미치는지에 대해 원산지별, 육류별로 추정하여 보다 합리적인 생산 및 소비 활동에 필요한 정보를 제공하는 데 의의를 가지고 있다. 또한, 축산 질병 관련 보도가 지속되는 시간을 추정하여 제시함으로써 소비 판촉 등의 홍보에도 반영할 수 있을 것으로 여겨진다.

Application of Cox and Parametric Survival Models to Assess Social Determinants of Health Affecting Three-Year Survival of Breast Cancer Patients

  • Mohseny, Maryam;Amanpour, Farzaneh;Mosavi-Jarrahi, Alireza;Jafari, Hossein;Moradi-Joo, Mohammad;Monfared, Esmat Davoudi
    • Asian Pacific Journal of Cancer Prevention
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    • 제17권sup3호
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    • pp.311-316
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    • 2016
  • Breast cancer is one of the most common causes of cancer mortality in Iran. Social determinants of health are among the key factors affecting the pathogenesis of diseases. This cross-sectional study aimed to determine the social determinants of breast cancer survival time with parametric and semi-parametric regression models. It was conducted on male and female patients diagnosed with breast cancer presenting to the Cancer Research Center of Shohada-E-Tajrish Hospital from 2006 to 2010. The Cox proportional hazard model and parametric models including the Weibull, log normal and log-logistic models were applied to determine the social determinants of survival time of breast cancer patients. The Akaike information criterion (AIC) was used to assess the best fit. Statistical analysis was performed with STATA (version 11) software. This study was performed on 797 breast cancer patients, aged 25-93 years with a mean age of 54.7 (${\pm}11.9$) years. In both semi-parametric and parametric models, the three-year survival was related to level of education and municipal district of residence (P<0.05). The AIC suggested that log normal distribution was the best fit for the three-year survival time of breast cancer patients. Social determinants of health such as level of education and municipal district of residence affect the survival of breast cancer cases. Future studies must focus on the effect of childhood social class on the survival times of cancers, which have hitherto only been paid limited attention.

우리나라 성인에서 혈청 지질성분비가 허혈성 심장질환 발생에 미치는 위험도 평가: 코호트 연구 (Associations of Serum Lipid Profiles with Incidence of Ischemic Heart Diseases in Korean Adults: Retrospective Cohort Study)

  • 신숙희;이태용
    • 한국산학기술학회논문지
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    • 제13권5호
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    • pp.2219-2231
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    • 2012
  • 본 연구에서는 우리나라 30세 이상 성인들의 허혈성심장질환(ischemic heart disease, IHD) 발생률을 계산하고, 지질지표(콜레스테롤, 중성지방, 고밀도지단백콜레스테롤, 저밀도지단백콜레스테롤)가 허혈성심장질환 발생에 미치는 위험도를 파악하고자 19개 대학 및 종합병원의 건강검진센터에서 검진을 받은 417,642명을 대상으로 1993년 9월부터 2009년 6월까지 평균 8.5년동안 허혈성심장질환의 발생을 추적관찰하였다. 자료수집은 검진자들에 대한 설문조사지를 이용하였고, 허혈성심장질환의 발생여부는 국민건강보험공단의 데이터베이스에서 확인하였다. 발생률은 발생밀도로 계산하였고, 혈청지질 지표에 따른 허혈성심장질환의 발생 위험도는 콕스의 비례위험 회귀모형을 이용하여 연령, BMI, 생활양식을 보정한 상태에서 성별에 따른 위험요인별 위험비와 95% 신뢰구간을 계산하였다. 연구결과 TC/HDL 비의 증가에 따라 IHD의 발생 위험비는 남자에서 1.21배에서 1.84배까지, 여자는 1.26배에서 1.86배까지 증가하였으며, TG/HDL 비의 증가에 따른 IHD의 발생 위험비는 남자에서 1.17배에서 1.49배까지, 여자는 1.42배에서 1.97배까지, LDL/HDL 비에 따라 IHD의 발생 위험비는 남자에서 1.26배에서 1.82배까지, 여자는 1.26배에서 1.68배까지 증가하였다. 결론적으로 혈청지질지표는 심혈관질환의 중요한 위험요인으로 총콜레스테롤, 저밀도지단백콜레스테롤, 중성지방은 혈중 농도가 높을수록, 고밀도지단백콜레스테롤은 낮을수록 IHD의 위험이 높아지는 것으로 나타났고, TC/HDL 비, TG/HDL 비, LDL/HDL 비에서 단독의 지질지표보다 위험도가 더 높게 나타나는 경향이 있었다. 따라서 추후 허혈성 심장질환의 예방 및 관리에는 혈청지질지표의 비도 감안하여야 한다.

Relationship Between Non-alcoholic Fatty Liver Disease and Decreased Bone Mineral Density: A Retrospective Cohort Study in Korea

  • Sung, Jisun;Ryu, Seungho;Song, Yun-Mi;Cheong, Hae-Kwan
    • Journal of Preventive Medicine and Public Health
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    • 제53권5호
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    • pp.342-352
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    • 2020
  • Objectives: The aim of this retrospective cohort study was to investigate whether non-alcoholic fatty liver disease (NAFLD) was associated with incident bone mineral density (BMD) decrease. Methods: This study included 4536 subjects with normal BMD at baseline. NAFLD was defined as the presence of fatty liver on abdominal ultrasonography without significant alcohol consumption or other causes. Decreased BMD was defined as a diagnosis of osteopenia, osteoporosis, or BMD below the expected range for the patient's age based on dual-energy X-ray absorptiometry. Cox proportional hazards models were used to estimate the hazard ratio of incident BMD decrease in subjects with or without NAFLD. Subgroup analyses were conducted according to the relevant factors. Results: Across 13 354 person-years of total follow-up, decreased BMD was observed in 606 subjects, corresponding to an incidence of 45.4 cases per 1000 person-years (median follow-up duration, 2.1 years). In the model adjusted for age and sex, the hazard ratio was 0.65 (95% confidence interval, 0.51 to 0.82), and statistical significance disappeared after adjustment for body mass index (BMI) and cardiometabolic factors. In the subgroup analyses, NAFLD was associated with a lower risk of incident BMD decrease in females even after adjustment for confounders. The direction of the effect of NAFLD on the risk of BMD decrease changed depending on BMI category and body fat percentage, although the impact was statistically insignificant. Conclusions: NAFLD had a significant protective effect on BMD in females. However, the effects may vary depending on BMI category or body fat percentage.

Chemoradiotherapy in squamous cell carcinoma of the anal canal: a single institution experience

  • Kim, Kyung Hwan;Chang, Jee Suk;Keum, Ki Chang;Ahn, Joong Bae;Lee, Chang Geol;Koom, Woong Sub
    • Radiation Oncology Journal
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    • 제31권1호
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    • pp.25-33
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    • 2013
  • Purpose: We reviewed the treatment outcomes and prognostic factors for patients with anal canal carcinoma who were treated with curative intent chemoradiotherapy (CRT) at Severance Hospital from 2005 to 2011. Materials and Methods: Data for 38 eligible patients treated during this period were reviewed. All patients were treated with curative intent using radiotherapy (RT) with (n = 35) or without concomitant chemotherapy (n = 3). Among 35 patients who received CRT, most of the chemotherapeutic regimens were either 5-fluorouracil (5-FU) plus mitomycin C (23 patients) or 5-FU plus cisplatin (10 patients). Recurrence-free survival (RFS), colostomy-free survival (CFS), overall survival (OS), and locoregional control (LRC) rates were calculated using the Kaplan-Meier method and survival between subgroups were compared using the log-rank test. Cox's proportional hazard model was used for multivariate analysis. Results: Over a median follow-up period of 44 months (range, 11 to 96 months), 3-year RFS, CFS, OS, and LRC were 80%, 79%, 85%, and 92%, respectively. In multivariate analysis, tumor size >4 cm was an independent predicting factor for poorer RFS (hazard ratio [HR], 6.35; 95% confidence interval [CI], 1.42 to 28.5; p = 0.006) and CFS (HR, 6.25; 95% CI, 1.39-28.0; p = 0.017), while the presence of external iliac lymph node metastasis was an independent prognosticator for poorer OS (HR, 9.32; 95% CI, 1.24 to 70.3; p = 0.030). No treatment-related colostomies or deaths occurred during or after treatment. Conclusion: Curative intent CRT resulted in excellent outcomes that were comparable to outcomes in previous randomized trials. No severe treatment-related toxicities were observed.

Association between Thioridazine Use and Cancer Risk in Adult Patients with Schizophrenia-A Population-Based Study

  • Chang, Cheng-Chen;Hsieh, Ming-Hong;Wang, Jong-Yi;Chiu, Nan-Ying;Wang, Yu-Hsun;Chiou, Jeng-Yuan;Huang, Hsiang-Hsiung;Ju, Po-Chung
    • Psychiatry investigation
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    • 제15권11호
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    • pp.1064-1070
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    • 2018
  • Objective Several cell line studies have demonstrated thioridazine's anticancer, multidrug resistance-reversing and apoptosis-inducing properties in various tumors. We conducted this nationwide population-based study to investigate the association between thioridazine use and cancer risk among adult patients with schizophrenia. Methods Based on the Psychiatric Inpatient Medical Claim of the National Health Insurance Research Database of Taiwan, a total of 185,689 insured psychiatric patients during 2000 to 2005 were identified. After excluding patients with prior history of schizophrenia, only 42,273 newly diagnosed patients were included. Among them, 1,631 patients ever receiving thioridazine for more than 30 days within 6 months were selected and paired with 6,256 randomly selected non-thioridazine controls. These patients were traced till 2012/12/31 to see if they have any malignancy. Results The incidence rates of hypertension and cerebrovascular disease were higher among cases than among matched controls. The incidence of hyperlipidemia, coronary artery disease and chronic pulmonary disease did not differ between the two groups. By using Cox proportional hazard model for cancer incidence, the crude hazard ratio was significantly higher in age, hypertension, hyperlipidemia, cerebrovascular disease, coronary artery disease and chronic pulmornary disease. However, after adjusting for other covariates, only age and hypertension remained significant. Thioridazine use in adult patients with schizophrenia had no significant association with cancer. Conclusion Despite our finding that thioridazine use had no prevention in cancer in adult patients with schizophrenia. Based on the biological activity, thioridazine is a potential anticancer drug and further investigation in human with cancer is warranted.

Survey of the use of statistical methods in Journal of the Korean Association of Oral and Maxillofacial Surgeons

  • Choi, Yong-Geun
    • Journal of the Korean Association of Oral and Maxillofacial Surgeons
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    • 제44권1호
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    • pp.25-28
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    • 2018
  • Objectives: This study aimed to describe recent patterns in the types of statistical test used in original articles that were published in Journal of the Korean Association of Oral and Maxillofacial Surgeons. Materials and Methods: Thirty-six original articles published in the Journal in 2015 and 2016 were ascertained. The type of statistical test was identified by one researcher. Descriptive statistics, such as frequency, rank, and proportion, were calculated. Graphical statistics, such as a histogram, were constructed to reveal the overall utilization pattern of statistical test types. Results: Twenty-two types of statistical test were used. Statistical test type was not reported in four original articles and classified as unclear in 5%. The four most frequently used statistical tests constituted 47% of the total tests and these were the chi-square test, Student's t-test, Fisher's exact test, and Mann-Whitney test in descending order. Regression models, such as the Cox proportional hazard model and multiple logistic regression to adjust for potential confounding variables, were used in only 6% of the studies. Normality tests, including the Kolmogorov-Smirnov test, Levene test, Shapiro-Wilk test, and $Scheff{\acute{e}}^{\prime}s$ test, were used diversely but in only 10% of the studies. Conclusion: A total of 22 statistical tests were identified, with four tests occupying almost half of the results. Adoption of a nonparametric test is recommended when the status of normality is vague. Adjustment for confounding variables should be pursued using a multiple regression model when the number of potential confounding variables is numerous.

Survival Rates and Risk Factors for Cephalad and L5-S1 Adjacent Segment Degeneration after L5 Floating Lumbar Fusion : A Minimum 2-Year Follow-Up

  • Lee, Young-Seok;Kim, Young-Baeg;Park, Seung-Won
    • Journal of Korean Neurosurgical Society
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    • 제57권2호
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    • pp.108-113
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    • 2015
  • Objective : Although the L5-S1 has distinct structural features in comparison with other lumbar spine segments, not much is known about adjacent segment degeneration (ASD) at the L5-S1 segment. The aim of study was to compare the incidence and character of ASD of the cephalad and L5-S1 segments after L5 floating lumbar fusion. Methods : From 2005 to 2010, 115 patients who underwent L5 floating lumber fusion were investigated. The mean follow-up period was 46.1 months. The incidence of radiological and clinical ASD of the cephalad and the L5-S1 segments was compared using survival analysis. Risk factors affecting ASD were analyzed using a log rank test and the Cox proportional hazard model. Results : Radiological ASD of the L5-S1 segment had a statistically significant higher survival rate than that of the cephalad segment (p=0.001). However, clinical ASD of the L5-S1 segment was significantly lower survival rates than that of the cephalad segment (p=0.038). Risk factor analysis showed that disc degeneration of the cephalad segment and preoperative spinal stenosis of the L5-S1 segment were risk factors. Conclusion : In L5 floating fusion, radiological ASD was more common in the cephalad segment and clinical ASD was more common in the L5-S1 segment. At the L5-S1 segment, the degree of spinal stenosis appears to be the most influential risk factor in ASD incidences, unlike the cephalad segment.

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

  • 최화영
    • 직업교육연구
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    • 제37권1호
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    • pp.119-138
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    • 2018
  • 이 연구에서는 중고령 자영업자를 대상으로 일자리 이탈 시점 및 일자리 이탈에 영향을 미치는 요인을 분석하고자 하였다. 고령화연구조사(KLoSA) 2006년 1차 조사대상자 중 자영업 시작 시기가 40세 이상인 684명을 대상으로 2014년 5차 조사 시기까지의 자료를 활용하여 콕스비례위험모형을 활용하였다. 이 연구의 주요 결론을 제시하면 다음과 같다. 첫째, 2005년 자영업을 운영하던 중고령 자영업자의 일자리 지속기간은 평균 15.5년으로 나타났으며 전체 684명 중 214명(31.3%)의 자영업자가 조사기간 내에 일자리를 이탈한 것으로 분석되었다. 둘째, 개인적 특성에서 성별, 창업 시 연령, 교육수준이 중고령 자영업자의 일자리 이탈에 유의미하게 영향을 미치는 것으로 나타났다. 여성일 때, 창업 시 연령이 많을 때, 대학 이상의 학력일 때 자영업 이탈에 대한 위험이 증가하였다. 셋째, 자영업 특성에서 업종과 직무만족이 중고령 자영업자의 일자리 이탈에 영향을 미치는 것으로 나타났다. 농림어업보다 숙박 및 음식업에 종사할 경우, 자영업에 만족하는 정도가 낮을수록 자영업 이탈에 대한 위험이 크게 나타났다. 이러한 결론을 바탕으로 다음과 같은 시사점을 제시하였다. 첫째, 여성 중고령 자영업자와 60대 이후에 자영업을 시작하는 고령 창업자에 대한 지원전략을 수립할 필요가 있다. 둘째, 진입장벽이 낮은 업종에서 창업하기보다 자신의 적성 및 경력을 활용하여 다양한 분야로 진출할 수 있도록 지원할 필요가 있다. 셋째, 노동환경에서 직무만족을 증진할 수 있도록 돕는 정책개발이 필요하며, 특히 고학력 자영업자에게는 자영업에 의한 다양한 보상에 만족할 수 있도록 할 필요가 있다.

우리나라 여성의 만혼(晩婚) 이 첫 출산간격에 미치는 영향 (Effects of the Late Marriage of Korean Women on the First-birth Interval)

  • 정우진;이경애;이선미
    • Journal of Preventive Medicine and Public Health
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    • 제39권3호
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    • pp.213-220
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    • 2006
  • Objectives: The purpose of this study was to examine the effect of women's late age of marriage on the interval between marriage and their first birth Methods: Data from Year 2000 Korea National Fertility Survey was collected through direct interview questionings, and the data was analyzed based on randomly selected sampling. In particular, the married women (N=5,648) were analyzed for the factors that determined the first-birth interval by performing Cox's proportional hazard model survival analysis. Results: Unlike previous findings, the woman whose age of marriage was 30 or more was more likely to delay the birth of her first baby than were the other women who married earlier. Further, a woman's age at marriage, a woman's residence before marriage, her husband's religion, her husband's level of education and the difference in age between the woman and her husband significantly influenced the first-birth interval. In contrast, for a married woman, her age, level of education, current residence and religion were not significant predictors of her first birth interval. Conclusions: Our study showed that women who married at the age of 30 years or more tend to postpone their first birth in Korea. When facing the increasing number of women who marry at a late age, the Korean government should implement population and social policies to encourage married women have their first child as early as possible.