Author

J.C. Stockton

Abstract

Background: The impact of neighbourhood physical environments on physical activity and health is widely acknowledged, with much research conducted to identify key factors. Results have been mixed, partly due to inconsistencies in how neighbourhoods are defined. This thesis examines relationships of physical environments with physical activity, and with depression, exploring influence of neighbourhood operationalisation. Method: Physical activity and depression outcomes were derived from a sample drawn from the seventh wave of the Whitehall II study conducted in 2004/5, and depression outcomes were also taken from the 2008 Health Survey for England. Neighbourhoods were operationalised at three levels of administrative geography and as residential postcode-centred GIS software-computed zones. Four main exposure variables were specified: a greenspace measure was constructed from the Generalised Land Use Database; an objective measure of environmental quality was derived from metadata of the Multiple Environmental Deprivation Index, and a subjective one from the 2008 Place Survey; and a walkability measure was constructed using GIS, drawing on several geographical databases. Multivariate logistic regression was used to measure statistical associations between exposures and outcomes, with adjustment for individual-level sociodemographic factors and area-level deprivation, and multilevel modelling was performed to estimate the contribution of neighbourhood characteristics relative to those of individuals to variation in outcomes. Results: Neighbourhood physical environments accounted for a small proportion of variation in all outcomes. Nevertheless, significant associations were found between all exposure variables and physical activity, independently of individual-level sociodemographic factors and area-level deprivation, the direction dependent on outcome specification. Only objectively measured environmental quality was significantly and independently with depression, with lower quality giving higher odds of this outcome. Strengths of associations were not substantively affected by neighbourhood operationalisation. Conclusion: This thesis increases understanding of physical environment attributes relevant to physical activity and depression in a European context and how neighbourhoods in which they are measured may best be defined.