Cities and population health

Abstract

A majority of the world's population will live in urban areas by 2007 and cities are exerting growing influence on the health of both urban and non-urban residents. Although there long has been substantial interest in the associations between city living and health, relatively little work has tried to understand how and why cities affect population health. This reflects both the number and complexity of determinants and of the absence of a unified framework that integrates the multiple factors that influence the health of urban populations. This paper presents a conceptual framework for studying how urban living affects population health. The framework rests on the assumption that urban populations are defined by size, density, diversity, and complexity, and that health in urban populations is a function of living conditions that are in turn shaped by municipal determinants and global and national trends. The framework builds on previous urban health research and incorporates multiple determinants at different levels. It is intended to serve as a model to guide public health research and intervention.

Fig. 1

A conceptual framework for Urban Health. Because of the complexity of the potential relations among the determinants of health of urban populations, our framework of necessity simplifies a number of potential relations between the domains shown here and discussed in the manuscript. A more detailed description of some of the plausible relations between key variables in the conceptual framework is provided in the text. We also note that the arrows in the figure are purely schematic and do not mean to be exhaustive or definitive. There are several interrelationships between the domains presented here and we would anticipate that most relationships would be multidirectional. This pictorial representation of the framework discussed in the text also is limited by its static nature. A fuller depiction of the determinants of the health of urban populations would incorporate the changes over time (e.g., growing city population) that in and of themselves are important determinants of health.