Defining the urban area for cross national comparison of health indicators: the EURO-URHIS 2 boundary study

Despite much research focusing on the impact of the city condition upon health, there still remains a lack of consensus over what constitutes an urban area (UA). This study was conducted to establish comparable boundaries for the UAs participating in EURO-URHIS 2, and to test whether the sample reflected the heterogeneity of urban living. Key UA contacts ( n = 28) completed a cross-sectional questionnaire, which included where available comparison between Urban Audit city and larger urban zone (LUZ) boundaries and public health administration areas (PHAAs). Additionally, broad health and demographic indicators were sought to test for heterogeneity of the EURO-URHIS 2 sample. Urban Audit city boundaries were found to be suitable for data collection in 100% ( n = 21) of UAs where Urban Audit data were available. The remainder ( n = 7) identified PHAA boundaries akin to the 'city' level. Heterogeneity was observed in the sample for population size and infant mortality rate. Heterogeneity could not be established for male and female life expectancy. This study was able to establish comparable boundaries for EURO-URHIS 2 data collection, with the 'city' area being selected for data collection. The homogeneity of life expectancy indicators was reflective of sub-regional similarities in life expectancy, whilst population estimates and rates of infant mortality indicated the presence of heterogeneity within the sample. Future work would trial these methods with a larger number of indicators and for a larger number of UAs.