The association between hospital obstetric volume and perinatal outcomes in California.

Objective: We sought to analyze the association between hospital obstetric volume and perinatal outcomes in California.

Study Design: This was a retrospective cohort study of births occurring in California in 2006. Hospitals were divided into 4 obstetric volume categories.

The role of ambient ozone in epidemiologic studies of heat-related mortality.

Background: A large and growing literature investigating the role of extreme heat on mortality has conceptualized the role of ambient ozone in various ways, sometimes treating it as a confounder, sometimes as an effect modifier, and sometimes as a co-exposure. Thus, there is a lack of consensus about the roles that temperature and ozone together play in causing mortality.

Objectives: We applied directed acyclic graphs (DAGs) to the topic of heat-related mortality to graphically represent the subject matter behind the research questions and to provide insight on the analytical options available.

Spatial modeling in environmental and public health research.

THIS PAPER HAS TWO AIMS: (1) to summarize various geographic information science methods; and (2) to provide a review of studies that have employed such methods. Though not meant to be a comprehensive review, this paper explains when certain methods are useful in epidemiological studies and also serves as an overview of the growing field of spatial epidemiology.