Glasgow's spatial arrangement of deprivation over time: methods to measure it and meanings for health

Background: Socio-economic deprivation is a key driver of population health. High levels of socio-economic deprivation have long been offered as the explanation for exceptionally high levels of mortality in Glasgow, Scotland. A number of recent studies have, however, suggested that this explanation is partial. Comparisons with Liverpool and Manchester suggest that mortality rates have been higher in Glasgow since the 1970s despite very similar levels of deprivation in these three cities. It has, therefore, been argued that there is an “excess” of mortality in Glasgow; that is, mortality rates are higher than would be expected given the city’s age, gender, and deprivation profile. A profusion of possible explanations for this excess has been proffered. One hypothesis is that the spatial arrangement of deprivation might be a contributing factor. Particular spatial configurations of deprivation have been associated with negative health impacts. It has been suggested that Glasgow experienced a distinct, and more harmful, development of spatial patterning of deprivation. Measuring the development of spatial arrangements of deprivation over time is technically challenging however. Therefore, this study brought together a number of techniques to compare the development of the spatial arrangement of deprivation in Glasgow, Liverpool and Manchester between 1971 and 2011. It then considered the plausibility of the spatial arrangement of deprivation as a contributing factor to Glasgow’s high levels of mortality. Methods: A literature review was undertaken to inform understandings of relationships between the spatial arrangement of deprivation and health outcomes. A substantial element of this study involved developing a methodology to facilitate temporal and inter-city comparisons of the spatial arrangement of deprivation. Key contributions of this study were the application of techniques to render and quantify whole-landscape perspectives on the development of spatial patterns of household deprivation, over time. This was achieved by using surface mapping techniques to map information relating to deprivation from the UK census, and then analysing these maps with spatial metrics. Results: There is agreement in the literature that the spatial arrangement of deprivation can influence health outcomes, but mechanisms and expected impacts are not clear. The temporal development of Glasgow’s spatial arrangement of deprivation exhibited both similarities and differences with Liverpool and Manchester. Glasgow often had a larger proportion of its landscape occupied with areas of deprivation, particularly in 1971 and 1981. Patch density and mean patch size (spatial metrics which provide an indication of fragmentation), however, were not found to have developed differently in Glasgow. Conclusion: The spatial extent of deprivation developed differently in Glasgow relative to Liverpool and Manchester as the results indicated that deprivation was substantially more spatially prevalent in Glasgow, this was particularly pronounced in 1971 and 1981. This implies that exposure of more affluent and deprived people to each other has been greater in Glasgow. Given that proximal inequality has been related to poor health outcomes, it would appear plausible that this may have adversely affected Glasgow’s mortality rates. If this is the case, however, it is unlikely that this will account for a substantial proportion of Glasgow’s excess mortality. Further research into Glasgow’s excess mortality is, therefore, required