Bayesian age-stratified joinpoint regression model: an application to lung and brain cancer mortality

Joinpoint regression model identifies significant changes in the trends of the incidence, mortality, and survival of a specific disease in a given population. The purpose of the present study is to develop an age-stratified Bayesian joinpoint regression model to describe mortality trend assuming that the observed counts are probabilistically characterized by the Poisson distribution. The proposed model is based on Bayesian model selection criteria with the smallest number of joinpoints that are sufficient to explain the Annual Percentage Change. The prior probability distributions are chosen in such a way that they are automatically derived from the model index contained in the model space. The proposed model and methodology estimates the age-adjusted mortality rates in different epidemiological studies to compare the trends by accounting the confounding effects of age. In developing the subject methods, we use the cancer mortality counts of adult lung and bronchus cancer, and brain and other Central Nervous System cancer patients obtained from the Surveillance Epidemiology and End Results data base of the National Cancer Institute.     

The Impact of Community Context on Land Use in an Agricultural Society

As an initial step toward new models of the population-environment relationship, this paper explores the relationship between community context and local land use in an agricultural setting. In this type of setting, we argue that aspects of the community context, such as schools and transportation infrastructure, impact important environmental characteristics, such as land use. We provide hypotheses which explain the mechanisms producing these effects. We then use data from a study of 132 communities in rural Nepal to test our hypotheses. These analyses show that community characteristics are strongly associated with land use in this agricultural setting. The results point toward changes in communities as critical determinants of environmental quality. These findings are consistent with the notion that changes in community contexts may also condition the population-environment relationship.