• Title/Summary/Keyword: Cox's proportional hazard model

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A Cohort Study of Physical Activity and All Cause Mortality in Middle-aged Men in Seoul (서울시 중년남성에서 육체적 활동량이 총 사망률에 미치는 영향에 관한 코호트 연구)

  • Kim, Dae-Sung;Koo, Hye-Won;Kim, Dong-Hyon;Bae, Jong-Myon;Shin, Myung-Hee;Lee, Moo-Song;Lee, Chung-Min;Ahn, Yoon-Ok
    • Journal of Preventive Medicine and Public Health
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    • v.31 no.4 s.63
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    • pp.604-615
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    • 1998
  • Although previous studies revealed the association of physical activity with mortality rate, it is unclear whether there is a linear trend between physical activity and mortality rate. In this study, the association of physical activity with the risk of all-cause mortality was analysed using Cox's proportional hazard model for a cohort of 14,204 healthy Korean men aged 40-59 years followed up for 4 years(Jan. 1993-Dec. 1996). Physical activity and other life style were surveyed by a postal questionnaire in December 1992. Total of 14,204 subjects were grouped into quartiles by physical activity. Using death certificate data, 123 deaths were identified. The second most active quartile had a lowest mortality .ate with relative risk of 0.44(95% C.I. : 0.23-0.84) compared with most sedentary quartile, showing a J-shape pattern of physical activity-mortality curve. By examining the difference in proportion of cause of the death between most active quartile and the other quartiles, there was no significant difference of proportional mortality from cardiovascular deaths, cerebrovascular deaths or deaths from trauma. The covariates were stratified into two group between which the trend of RR was compared to test the effect modification. There was no remarkable effect modification by alcohol intake, smoking, body mass index, calorie consumption, percent fat consumption. In conclusion, moderate activity was found to have more protective effect on all-cause mortality than vigorous activity and that the J-shape pattern of physical activity-mortality curve was not due to the difference of mortality pattern or effect modification by alcohol intake, smoking, body mass index, calorie consumption and percent fat consumption.

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Risk Factors for Recurrent Pneumothorax after Primary Spontaneous Pneumothorax (원발 기흉 수술 후 재발의 위험인자)

  • Yu, Jai-Kun;Lee, Seong-Ki;Seo, Hong-Joo;Seo, Min-Bum
    • Journal of Chest Surgery
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    • v.41 no.6
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    • pp.724-728
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    • 2008
  • Background: The purpose of this study was to identify factors associated with recurrent pneumothorax after wedge resection in primary spontaneous pneumothorax in our hospital. Material and Method: Two hundred thirty-five consecutive patient (98% males; mean age, $23.9{\pm}4.5$ years) who had undergone video-assisted thoracoscopic surgery (VATS) were reviewed retrospectively. The two groups were divided as follows: group A, non-recurrent patients (225 patients [96%]); and group B, recurrent group (10 patients [4%]); the risk factors were compared between the two groups. The single and multiple factors that influenced the recurrence rate were analyzed using Cox's proportional hazard model. Result: There were no significant differences between the recurrent and non-recurrent groups in terms of gender, smoking, site of recurrence, degree of collapse, operative time, and number or weight of resected bullae. The recurrence rate was significantly more common in the following: younger ages, increased height/weight ratio, longer initial air leakage period, and shorter duration of chest drainage. Early aggressive exercise (<30 days) of patients after wedge resection increased the tendency for recurrence. Conclusion: Thoracoscopic wedge resection does not have a higher recurrence rate than open thoracotomy. However, young age, height/weight ratio, continuous air, and duration of chest tube placement were risk factors for a recurrent pneumothorax.

Fasting Serum Glucose and Subsequent Liver Cancer Risk in a Korean Prospective Cohort (공복 혈당과 간암 발생 위험에 관한 코호트 연구)

  • Gwack, Jin;Hwang, Seung-Sik;Ko, Kwang-Pil;Jun, Jae-Kwan;Park, Sue-Kyung;Chang, Soung-Hoon;Shin, Hai-Rim;Yoo, Keun-Young
    • Journal of Preventive Medicine and Public Health
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    • v.40 no.1
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    • pp.23-28
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    • 2007
  • Objectives : Chronic infections with hepatitis B or C and alcoholic cirrhosis are three well-known major risk factors for liver cancer. Diabetes has also been suggested as a potential risk factor. However, the findings of previous studies have been controversial in terms of the causal association. Therefore, the aim of this study was to evaluate the association between serum glucose levels and liver cancer development in a Korean cohort. Methods : Thirty-six liver cancer cases were identified in the Korean Multi-Center Cancer Cohort (KMCC). Baseline information on lifestyle characteristics was obtained via questionnaire. Serum glucose levels were measured at the study's enrollment. Relative risks (RRs) were estimated using a Cox proportional hazard regression model. The adjusting variables included age, gender, smoking history, alcohol consumption, body mass index, and hepatitis B surface antigen (HBsAg) seropositivity. Results : The RRs of serum glucose for liver caner were 1.20 (95% CI = 0.48-2.99) for the category of 100 to 125 mg/dL of serum glucose and 2.77 (95% CI = 1.24-6.18) for the >126 mg/dL serum glucose category (both compared to the <100 mg/dL category). In a subgroup analysis, the RR of serum glucose among those who were both HBsAg seronegative and non-drinkers was 4.46 (95% CI = 1.09-18.28) for those with glucose levels >100 mg/dL. Conclusions : The results of this study suggest that a high level of serum glucose can increase liver cancer risk independently of hepatitis infection and drinking history in Koreans. This study implies that glucose intolerance may be an independent risk factor for liver cancer.

Clinical Prognostic Factors of Terminal Cancer Patients with Palliative Procedures for Malignant Gastrointestinal Obstruction (완화적 시술을 받은 악성 위장관 폐색 말기 암환자의 임상적 예후인자)

  • Moon, Do-Ho;Choe, Wha-Sook
    • Journal of Hospice and Palliative Care
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    • v.8 no.2
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    • pp.200-208
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    • 2005
  • Purpose: Palliative procedures or surgical interventions not only manage various symptoms of malignant gastrointestinal obstruction, but also improve the quality of life. We investigated the clinical characteristics and prognostic factors of terminal cancer patients with palliative procedures for malignant gastrointestinal obstruction. Methods: We retrospectively reviewed the medical records of 48 terminal cancer patients with palliative procedures for malignant gastrointestinal obstruction at Sam Anyang hospital from May in 2002 to May in 2005. We excluded patients with palliative tumor resection. We analyzed prognostic factors in symtom-free survival and overall survival using Kaplan-Meier method, univariate and multivariate analysis. Results: There were 25 males (52%) and 23 females (48%), and median age of 48 patients was 65 years. The most common cause of malignant gastrointestinal obstruction was colorectal (26 patients, 55%), followed by stomach (10, 21%). Twenty patients (42%) received previous treatment (chemotherapy, surgery, and radiotherapy) and 28 (58%) never received any. Eighteen of 20 had received chemotherapy. The most common symptom was pain (15 patients, 31%). Twenty three patients (48%) had Eastern Cooperative Oncology Group(ECOG) performance status of 1 or 2 score and 25 patients (52%) 3 or 4 score. The most common palliative procedure was colostomy and there was no mortality concerning the palliative procedures. By univariate and multivariate analysis, performance status was the only independent prognostic factor in overall survival and symptom-free survival. Overall survival was 150 days and symptom-free survival was 90 days. Conclusion:. We confirmed that perftatdormance status is significant independent prognostic factor in terminal cancer patients with palliative procedures for malignant gastrointestinal obstruction.

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Gamma Knife Radiosurgery for Brain Metastases from Breast Cancer

  • Jo, Kyung Il;Im, Young-Hyuck;Kong, Doo Sik;Seol, Ho Jun;Nam, Do-Hyun;Lee, Jung-Il
    • Journal of Korean Neurosurgical Society
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    • v.54 no.5
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    • pp.399-404
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    • 2013
  • Objective : The authors conducted a retrospective cohort study to determine prognostic factors and treatment outcomes of brain metastases (BM) from breast cancer (BC) after Gamma Knife radiosurgery (GKS). Methods : Pathologic and clinical features, and outcomes were analyzed in a cohort of 62 patients with BM from BC treated by GKS. The Kaplan- Meier method, the log-rank test, and Cox's proportional hazards model were used to assess prognostic factors. Results : Median survival after GKS was 73.0 weeks (95% confidence interval, 46.0-100.1). HER2+ [hazard ratio (HR) 0.441; p=0.045], Karnofsky performance scale (KPS) ${\geq}70$ (RR 0.416; p=0.050) and systemic chemotherapy after GKS (RR 0.282; p=0.001) were found to be a favorable prognostic factor of overall survival. Actuarial local control (LC) rate were $89.5{\pm}4.5%$ and $70.5{\pm}6.9%$ at 6 and 12 months after GKS, respectively. No prognostic factors were found to affect LC rate. Uni- and multivariate analysis revealed that the distant control (DC) rate was higher in patients with; a small number (${\leq}3$) of metastasis (HR 0.300; p=0.045), no known extracranial metastasis (p=0.013, log-rank test), or the HER2+ subtype (HR 0.267; p=0.027). Additional whole brain radiation therapy and metastasis volume were not found to be significantly associated with LC, DC, or overall survival. Conclusion : The treatment outcomes of patients with newly diagnosed BM from BC treated with GKS could be affected primarily by intrinsic subtype, KPS, and systemic chemotherapy. Therapeutic strategy and prognosis scoring system should be individualized based on considerations of intrinsic subtype in addition to traditionally known parameters related to stereotactic radiosurgery.

Association between Cigarette Smoking History and Mortality in 36,446 Health Examinees in Korea

  • Kim, Kyoungwoo;Yoo, Taiwoo;Kim, Yeonju;Choi, Ji-Ho;Myung, Seung-Kwon;Park, Sang-Min;Hong, Yun-Chul;Cho, Belong;Park, Sue K.;Yoo, Keun-Young
    • Asian Pacific Journal of Cancer Prevention
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    • v.15 no.14
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    • pp.5685-5689
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    • 2014
  • Background: It is well known that smoking is a preventable factor for all-cause mortality; however, it is still questionable how many years after smoking cessation that people will have reduced risk for mortality, in particular in those with a high interest in their own health. We aimed to examine the association between time since quitting smoking and total mortality among past-smokers relative to current smokers. Materials and Methods: We enrolled 36,446 health examinees that voluntarily taken with diverse health check-up packages of high cost burden in 1995-2003 and followed them till death by 2004. The history of cigarette smoking consumption was collected using a self-administrative questionnaire at the first visit time. Mortality risk by smoking cessation years was analyzed using Cox's proportional hazard model. Results: Compared to non-smokers, male smokers over 15 pack-years had higher risk for total mortality (HR=1.60, 95%CI 1.23-2.14). The mortality risk in female smokers with same pack-years was more pronounced than that in male smokers (HR=2.83, 95%CI 1.17-7.04) despite a small number of cases. Compared to current smokers, a decrease of total mortality was observed among those who ceased smoking, and inverse dose-response was found with years after cessation: RR 0.98 (95%CI, 0.64-1.41) (<2 yrs), 0.60 (95%CI, 0.43-0.83) (3-9 yrs), and 0.58 (95%CI, 0.43-0.79) (${\geq}10$ yrs). Conclusions: A reduced risk of total mortality was observed after 3 years of smoking cessation. Our findings suggest that at least 3 years of smoking cessation may contribute to reduce premature mortality among Asian men.

Cigarette Smoking and Gastric Cancer Risk in a Community-based Cohort Study in Korea (흡연과 위암 발생의 관련성에 관한 지역사회 기반의 코호트 연구)

  • Kim, Yeon-Ju;Shin, Ae-Sun;Gwack, Jin;Jun, Jae-Kwan;Park, Sue-Kyung;Kang, Dae-Hee;Shin, Hai-Rim;Chang, Soung-Hoon;Yoo, Keun-Young
    • Journal of Preventive Medicine and Public Health
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    • v.40 no.6
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    • pp.467-474
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    • 2007
  • Objectives : Gastric cancer is the most common incident cancer in Korea. Although Helicobacter pylori infection is the most important risk factor for the development of gastric cancer, cigarette smoking has also been suggested to play an important role in the development of gastric cancer. The objective of this study is to evaluate the relationship between cigarette smoking and gastric cancer risk in a Korean population. Methods : The study population consisted of 13,785 subjects who had been enrolled in the Korean Multi-Center Career Cohort between 1993 and 2002. As of December 2002, 139 incident gastric cancer cases were ascertained through the Korea Central Cancer Registry and the National Death Certificate Database. Relative risks (RR) and 95% confidence intervals (CI) for gastric cancer were estimated using Cox#s proportional hazard model adjusted for age, education, alcohol drinking status and history of gastritis or ulcer. Results : Significant dose-response relationships were observed between the duration of smoking and the risk of gastric cancer among the male subjects in comparison to non-smokers: men who smoked for 20-39 years had a 2.09-fold (95% CI 1.00-4.38) increase, and those who smoked for more than 40 years had a 3.13-fold (95% CI 1.59-6.17) increase in the risk of gastric cancer ($P_{trend}<0.01$). Conclusions : This study suggests that a longer duration of cigarette smoking may increase the risk of gastric cancer development in a dose-response manner in Korean men. The association between smoking and gastric cancer risk in women should be verified in future studies with a larger number of cases.

Association between BMI and Mortality - Kangwha cohort study - (BMI와 사망과의 관련성 - 강화 코호트 연구 -)

  • Yoon, Soo-Jin;Yi, Sang-Wook;Kim, Soh-Yoon;Lee, Soon-Young;Park, Yun-Hee;Sohn, Tae-Yong;Ohrr, Hee-Choul
    • Journal of Preventive Medicine and Public Health
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    • v.33 no.4
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    • pp.459-468
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    • 2000
  • Objectives : To investigate the association between BMI and Mortality. Methods : This study was based on the analysis and assembly of the 'Kangwha Cohort Study', previously conducted by the Department of Preventive Medicine, Yonsei University. A total of 2,696 males and 3,595 females were followed for almost ten years and ten months from March 1985 to January 1996, a total of whom 2,420 died during this period. The Cox's proportional hazards regression model was used to analyze this data. Results : We found a U-shaped relationship between BMI and mortality among the aged men in the Kangwha cohort. The hazard ratio of dying was adjusted for age, marital status, occupation, self cognitive health level, chronic disease, smoking, and alcohol frequency, then sorted by body mass index into the following groups; less than 10.5, 18.5 to less than 21.0, 21.0 to less than 23.5, 23.5 to less than 26.0 and greater than or equal to 26. The corresponding ratios for men were 1.81(1.50-2.19, 95%CI), 1.31(1.14-1.51, 95%CI), 1.0(referent), 1.05(0.87-1.26, 95%CI) and 1.39(1.09-1.76, 95%CI), respectively. And for women, 1.46(1.19-1.78), 1.12(0.95-1.31, 95%CI), 1.0(referent), 1.00(0.84-1.20, 95%CI) and 1.09(0.89-1.34, 95%CI), respectively. Conclusions : The risk of death among aged men in Kangwha increased in the under and overweight groups. The relationship between BMl and mortality has been well studied in Western populations, but little is known about the association between BMI and mortality in our country. So, on the basis of this study, it is apparent that more studies of the relationship between BMI and mortality will be needed for future work.

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Efficacy of First-Line Targeted Therapy in Real-World Korean Patients with Metastatic Renal Cell Carcinoma: Focus on Sunitinib and Pazopanib

  • Kim, Myung Soo;Chung, Ho Seok;Hwang, Eu Chang;Jung, Seung Il;Kwon, Dong Deuk;Hwang, Jun Eul;Bae, Woo Kyun;Park, Jae Young;Jeong, Chang Wook;Kwak, Cheol;Song, Cheryn;Seo, Seong Il;Byun, Seok-Soo;Hong, Sung-Hoo;Chung, Jinsoo
    • Journal of Korean Medical Science
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    • v.33 no.51
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    • pp.325.1-325.10
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    • 2018
  • Background: To evaluate survival outcomes and prognostic factors for overall survival (OS) in patients with metastatic renal cell carcinoma (mRCC) who received sunitinib (SU) and pazopanib (PZ) as first-line therapy in real-world Korean clinical practice. Methods: Data of 554 patients with mRCC who received SU or PZ at eight institutions between 2012 and 2016 were retrospectively reviewed. Based on the targeted therapy, the patients were divided into SU (n = 293) or PZ (n = 261) groups, and the clinicopathological variables and survival rates of the two groups were compared. A multivariable Cox proportional hazard model was used to determine the prognostic factors for OS. Results: The median follow-up was 16.4 months (interquartile range, 8.3-31.3). Patients in the PZ group were older, and no significant difference was observed in the performance status (PS) between the two groups. In the SU group, the dose reduction rate was higher and the incidence of grade 3 toxicity was more frequent. The objective response rates were comparable between the two groups (SU, 32.1% vs. PZ, 36.4%). OS did not differ significantly between the two groups (SU, 36.5 months vs. PZ, 40.2 months; log-rank, P = 0.955). Body mass index, Eastern Cooperative Oncology Group PS > 2, synchronous metastasis, poor Heng risk criteria, and liver and bone metastases were associated with a shorter OS. Conclusion: Our real-world data of Korean patients with mRCC suggested that SU and PZ had similar efficacies as first-line therapy for mRCC. However, PZ was better tolerated than SU in Korean patients.

Preoperative Risk Factors for Pathologic N2 Metastasis in Positron Emission Tomography-Computed Tomography-Diagnosed N0-1 Non-Small Cell Lung Cancer

  • Yoon, Tae-hong;Lee, Chul-ho;Park, Ki-sung;Bae, Chi-hoon;Cho, Jun-Woo;Jang, Jae-seok
    • Journal of Chest Surgery
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    • v.52 no.4
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    • pp.221-226
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    • 2019
  • Background: Accurate mediastinal lymph node staging is vital for the optimal therapy and prognostication of patients with lung cancer. This study aimed to determine the preoperative risk factors for pN2 disease, as well as its incidence and long-term outcomes, in patients with clinical N0-1 non-small cell lung cancer. Methods: We retrospectively analyzed patients who were treated surgically for primary non-small cell lung cancer from November 2005 to December 2014. Patients staged as clinical N0-1 via chest computed tomography (CT) and positron emission tomography (PET)-CT were divided into two groups (pN0-1 and pN2) and compared. Results: In a univariate analysis, the significant preoperative risk factors for pN2 included a large tumor size (p=0.083), high maximum standard uptake value on PET (p<0.001), and central location of the tumor (p<0.001). In a multivariate analysis, central location of the tumor (p<0.001) remained a significant preoperative risk factor for pN2 status. The 5-year overall survival rates were 75% and 22.9% in the pN0-1 and pN2 groups, respectively, and 50% and 78.2% in the patients with centrally located and peripherally located tumors, respectively. In a Cox proportional hazard model, central location of the tumor increased the risk of death by 3.4-fold (p<0.001). Conclusion: More invasive procedures should be considered when preoperative risk factors are identified in order to improve the efficacy of diagnostic and therapeutic plans and, consequently, the patient's prognosis.