Semiparametric hazard function regression models are among the well studied risk models in survival analysis. The Cox proportional hazards model has been a popular choice in modelling data from epidemiological settings. The Cox-Aalen model is one of the tools for handling the problem of non-proportional effects in the Cox model. We show an application on Piedmont cancer registry data. We initia...

background: the aim of this study was to detect prognostic factors in recurrent breast cancer metastasis. materials and methods: th is retrospective cohort study employed data from 996 breast cancer patients of isfahan seyed-o-shohada research center from 1998 to 2010. stratifi ed cox proportional hazards model, marginal approach, was used to evaluate the prognostic value of estrogen receptor, ...

abstract         in the increasing population of the elderly in iran, so far no prospective health studies have been undertaken.   this study was conducted to identify the risk factors of survival time of the elderly of ages above 60 years. material and methods: individuals above 60 years old were recruited in the primary phase of the tehran lipid and glucose study (tlgs) during 1998-2001. they...

this study was designed to investigate causes of culling in industrial dairy herds in fars province and to describe the pattern of reason-specific culling with respect to age of animal and interval from calving to culling. a total number of 9 dairy herds were selected for the study and information about culling reasons, birth date, last calving date and culling date was collected for culled cow...

background & aim: esophageal cancer is one of the main common causes of death. the high prevalence of esophageal cancer in northern iran is an important public health problem. the main aim of this paper was to assess the factors affecting survival of  atients with esophageal cancer in neighbor provinces around the caspian sea using weibull mixture cure model and mixture cure model based on a no...