The science of healthy cities : deciphering the associations between urban morphometrics and health outcomes

Over the past decade there has been mounting evidence of the significant role played by the myriad attributes of our city's built environments in shaping our health and well-being. This thesis hypothesizes that the constituent components of the built environment, especially the configuration and design of land uses and street networks governs the distribution of resources and services, configures the neighbourhood activity space, and thereby influences individual physical activity behaviours, social interactions, weight outcomes as well as mental health and well being. Enhanced accessibility to health-promoting community resources improves local opportunities for physical activity, thereby enhancing mobility, social interactions and independence as well as reducing isolation. The first section of this thesis conceptualizes the urban health niche as a novel holistic and spatially-explicit paradigm in public health and proposes a health niche model of healthy city. Based on the proposed paradigm and gathered research evidence, multilevel data sets pertaining to health, socio-economic, built and natural environment have been produced and integrated together to constitute the high resolution database, spatial Design Network Analysis for Urban Health (sDNA-UH). sDNA-UH has been developed for the assembly constituency of Caerphilly, South Wales enabling operationalization of the spatial elements of the proposed urban health niche. State-of-the-art spatial and network analysis techniques have been employed upon the UK Ordnance Survey Mastermap data layers to quantify the various facets of urban built environment in the form of built environment morphological metrics (morphometrics) with the potential to influence individual's health. Based on the developed sDNA-UH, a series of three empirical studies comprising multilevel cross-sectional and longitudinal models have been presented which examine the association between specific attributes of a built environment and health outcomes. Firstly, a two-part multi-level regression model was employed to examine the impact of built environment configuration upon psychological distress. Land use mix, density of amenities, local street-network general accessibility (‘betweenness’) and slope variability were identified as significant predictors. Secondly, the first long-term longitudinal evidence relating the built environment to change in obesity in older people identified land use mix, density of amenities street network accessibility and slope variability as significant predictors. The third study examined the health effects of differential accessibility of an individual's dwelling with respect to multiple service and facility catchments at multiple spatial scales. Dwelling level density, dwelling type, density of community services, street network movement potential expressed in terms of betweenness index as well as neighbourhood-level deprivation were identified as the significant parameters. The study reported significant differences in point estimates and level of significance when comparing the two spatial scales of 0.5 and 1.0 mile street network catchments. The empirical evidence thus generated lends support to the thesis’ principal hypothesis that the built environment influences individual health behaviour and eventually health. The research concludes that optimized design and planning of urban built environments act as effective public health intervention in our goal of health-sustaining communities and a healthy city.