S-Space College of Natural Sciences (자연과학대학) Dept. of Statistics (통계학과) Theses (Master's Degree_통계학과)
A Cox Proportional Hazard Model with Time-Varying Coefficients Using Revised Survival Time to Investigate Stroke Risk Factors : 뇌졸중 위험요인 분석을 위하여 개선된 생존시간을 이용하는 시간변동계수를 포함한 Cox 비례위험모형
- Myunghee Cho Paik
- 자연과학대학 통계학과
- Issue Date
- 서울대학교 대학원
- stroke ; Northern Manhattan stroke study ; Cox proportional hazard model ; survival time ; proportional hazard assumption ; time-varying coefficient
- 학위논문 (석사)-- 서울대학교 대학원 : 통계학과, 2014. 2. Myunghee Cho Paik.
- According to estimates by World Health Organization (WHO), globally, cardiovascular disease is the first leading cause of death. Among various cardiovascular diseases, the risk of stroke is constantly increasing even though the mortality rate for it is decreasing. Including representative studies, Framingham study and Northern Manhattan stroke study (NOMAS), many of studies relating to the risk factors of stroke have been performed. In this study, using the dataset obtained from NOMAS, the Cox proportional hazard model is used in order to investigate stroke risk factors. In particular, the NOMAS used follow-up time to onset of stroke, whereas, in this study, the age of having a stroke is treated as survival time for fitting the models. The proportional hazard assumption is evaluated through graphs, and some risk factors whose risk effects vary according to the variation of age are detected. The pattern of change and the significance of these risk effects are evaluated by constructing a Coxs model with time-varying coefficients. In addition to the study concerning occurrence of all types of strokes, the study concentrating only on the ischemic stroke occurrence is also performed and these two are compared.