Invited commentary: history of place, life course, and health inequalities-historical geographic information systems and epidemiologic research

In recent years, a large number of studies have investigated the sociogeographical arrangements of health-related characteristics across urban areas. Drawing on theories of "environmental justice," researchers have been concerned with whether there is a social gradient in the spatial distribution of environmental "goods" and "bads." The accompanying article by King and Clarke (Am J Epidemiol. 2015;181(1):17-25) makes an important entry into these debates, as it describes the results of the first national-level US study to examine the relationship between urban form (particularly neighborhood walkability) and various area-level sociodemographic measures. Like many studies in this field, King and Clarke's work was constrained by the availability of certain area-level measures, and they had to rely on data from only a single point in time (2000-2001). For this reason, their results can provide few insights into the processes leading to the geographical arrangement of health-related resources across US cities. The emerging field of "historical geographic information systems" offers possibilities to researchers interested in relationships between place and health. Integrating spatial data from various historical sources can enable the reconstruction of past urban environments. These spatial data, accrued over time and appended with detailed cohort information, will offer analytical opportunities for better understanding how place-based factors influence health and well-being over the life course.