The built environment and health: a spatial analysis of type 2 diabetes and childhood weight status in urban New Zealand.

The built environment is an integral aspect of everyday life. It provides the context in which individual behaviours are set and can affect both individual and population health. It is shaped by distal systematic drivers which influence demographic and epidemiological changes such as the globalisation of economic processes, urbanisation, mechanisation, changing agricultural and trade policies, and dietary transitions. These systematic drivers, in turn, influence local environments which act as proximal determinants of population outcomes. Subsequently, the contextual impact of the local built environment is considered to be an influential aspect of spatial disparities in population health outcomes. The focus of this thesis is on health outcomes of high weight status in children and population level Type 2 Diabetes Mellitus (T2DM). The prevalence of these health issues has increased alongside societal, demographic and cultural changes. While there are various biological, behavioural and environmental risk factors which influence the development of these health issues there is still much to be learned about both direct and indirect causes. The overall aim of this thesis is to analyse the built environment in urban New Zealand and investigate associations with the spatial epidemiology of two health outcomes, high weight status in children and population level T2DM. Despite substantial research and significant public attention directed toward these health issues within Aotearoa New Zealand, there are still critical gaps in the spatial understanding of such health outcomes. Current literature also highlights a lack of research which focuses on T2DM. This thesis addresses such research gaps using an ecological approach to analysis which utilises Geographic Information Systems (GIS) and spatial epidemiological methods. This is the first study in New Zealand to spatially quantify the effects of multiple environmental exposures on health outcomes of both high weight status in children and population level T2DM, for all urban areas, using a geospatial approach. It establishes novel measures of the built environment using data on fast food outlets, takeaways, dairy/convenience stores, supermarkets, fruit and vegetable stores, physical activity facilities, and greenspace to assess potential associations between contextual factors and health outcomes. In the context of this study, the former three of these categories are considered unhealthy exposures and detrimental to overall health. The latter four categories, in contrast, are considered to be healthy exposures and health-promoting. This thesis has, in turn, made original contributions to the current body of knowledge by: (1) including the use of both established and novel approaches to measuring various aspects of the built environment, and (2) analysing spatial data on health outcomes of high weight status in children and population level T2DM for all urban areas of New Zealand and assessing potential associations with the built environment. Such analysis also provides the opportunity to assess how the built environment may relate to not only outcomes of multiple chronic health conditions, but also different population groups. When considering relationships between measures of the built environment and socioeconomic deprivation, results of this study indicate that accessibility to both and unhealthy and healthy exposures is generally higher in the most deprived areas compared to the least deprived areas. This study also found some notable results when looking at the spatial distribution of both high weight status in children and population level T2DM, finding that T2DM is more spatially clustered than high weight status in children. Both health outcomes were also shown to be heavily influenced by demographic factors and associated with accessibility to environmental exposures. Interestingly, results show that both of these health issues may be more heavily influenced by health-promoting resources than those considered detrimental to health. Health-promoting resources were shown to have a consistently positive effect on both health outcomes, while those considered detrimental to health showed varying, and largely insignificant, associations. Caution must be exercised, however, to ensure that a balanced approach is taken within prevention efforts which addresses environmental factors as well as economic accessibility, individual behaviours and societal norms. The current study has implications for both policy and future research efforts as a deeper knowledge of local environments forms a basis on which to better understand spatial associations between the built environment and health as well as formulate policy directed toward environmental influences on chronic health conditions. It is vital to consider such contextual influences in order to better understand the spatial epidemiology of chronic health conditions in Aotearoa New Zealand. Accounting for these contextual influences within both research and policy can not only enhance understandings of such health concerns, but can also identify opportunities for prevention efforts. This thesis has, in turn, provided insight into such associations and a base from which to further address the complexities of such issues using a geospatial approach

National movement patterns during the COVID-19 pandemic in New Zealand:The unexplored role of neighbourhood deprivation

BACKGROUND: The COVID-19 pandemic has asked unprecedented questions of governments around the world. Policy responses have disrupted usual patterns of movement in society, locally and globally, with resultant impacts on national economies and human well-being. These interventions have primarily centred on enforcing lockdowns and introducing social distancing recommendations, leading to questions of trust and competency around the role of institutions and the administrative apparatus of state. This study demonstrates the unequal societal impacts in population movement during a national ‘lockdown’. METHODS: We use nationwide mobile phone movement data to quantify the effect of an enforced lockdown on population mobility by neighbourhood deprivation using an ecological study design. We then derive a mobility index using anonymised aggregated population counts for each neighbourhood (2253 Census Statistical Areas; mean population n=2086) of national hourly mobile phone location data (7.45 million records, 1 March 2020–20 July 2020) for New Zealand (NZ). RESULTS: Curtailing movement has highlighted and exacerbated underlying social and spatial inequalities. Our analysis reveals the unequal movements during ‘lockdown’ by neighbourhood socioeconomic status in NZ. CONCLUSION: In understanding inequalities in neighbourhood movements, we are contributing critical new evidence to the policy debate about the impact(s) and efficacy of national, regional or local lockdowns which have sparked such controversy

Health Status

Percentage of the population with a range of self-reported health status for Statistical Area 2 (2018) units. Original data sourced from Census 2018 and New Zealand Health Survey 2017/18 and 2018/19. Data provided are synthetic data produced from spatial microsimulation modelling.</p

Well-being

Mean personal well-being index (PWI) and national well-being index (NWI) scores for Statistical Area 2 (2018) units. Original data sourced from Census 2018 and New Zealand Attitudes and Values Study 2018. Data provided are synthetic data produced from spatial microsimulation modelling. </p

Mental Health

Percentage of the population with self-reported mental health outcomes of anxiety, bipolar and depression for Statistical Area 2 (2018) units. Original data sourced from Census 2018 and New Zealand Health Survey 2017/18 and 2018/19. Data provided are synthetic data produced from spatial microsimulation modelling.</p

Healthcare Costs

Percentage of the population with unmet healthcare need due to cost for Statistical Area 2 (2018) units. Original data sourced from Census 2018 and New Zealand Health Survey 2017/18 and 2018/19. Data provided are synthetic data produced from spatial microsimulation modelling.</p

Accessibility to food retailers and socio-economic deprivation in urban New Zealand

The spatial locations of food retailers are considered to be an influential aspect of population consumption patterns. Such contextual relationships are often related to socioeconomic deprivation, with disparities in accessibility having important implications. This study used Geographic Information Systems and an Enhanced Two-Step Floating Catchment Area model of spatial accessibility to further understand such relationships within urban areas of New Zealand. Findings, while mixed, indicate that there is generally increased accessibility to all food retailers in highly deprived areas. Understanding these socio-spatial relationships in local environments has important implications for policy initiatives, health outcomes and sustainable development

Towards a better understanding of residential mobility and the environments in which adults reside: a nationwide geospatial study from Aotearoa New Zealand

This nationwide geospatial study from Aotearoa New Zealand describes the frequency and spatial patterning of residential mobility and examines the interplay between patterns of residential mobility and the environments in which adults reside. Data from the Integrated Data Infrastructure (n=4,781,268 adults) defined levels of residential mobility in 2016–2020. We then used nationwide environmental data included within the New Zealand Healthy Location Index to define access to a range of health-promoting and health-constraining features. We identified 29 spatial clusters based on the mobility characteristics of the population living within selected administrative units that were further classified into five groups based on the similarity of residential mobility groups. Each group was described by its relation to the Healthy Location Index, urbanicity and ethnicity. A greater proportion of residential mobility was related to metropolitan and large regional centres, and Māori, Pacific and Asian ethnicities. Areas with higher levels of vulnerable mobile population were identified in the North Island (Northland, Gisborne, Whanganui and urban pockets of Auckland, Hamilton, Napier and Hastings). While there was poor access to health-promoting features for the mobile population living in the inner cities, areas with higher residential mobility are associated with better access to health-promoting and neutral environments

Understanding vulnerability to COVID-19 in New Zealand: a nationwide cross-sectional study

COVID-19 can affect the entire population, but it poses an increased risk for particular population groups. Socioeconomic and demographic factors, as well as long-term health conditions, can make populations vulnerable to adverse health outcomes and mortality related to COVID-19. This study uses geospatial methods to visualise metrics of vulnerability to COVID-19 in New Zealand. Based on Ministry of Health guidelines, nationwide data on risk factors included age, ethnicity, population density, socioeconomic deprivation, smoking, long-term health conditions (cancer, cardiovascular conditions, diabetes, renal conditions, and respiratory illnesses), and health service awareness. Data were sourced from the Census (2018), the New Zealand Deprivation Index (NZDep2018), and the National Minimum Dataset (2011– 2016). Factor analysis and bivariate mapping were used to identify areas of high vulnerability. Results demonstrate the unequal social and spatial vulnerabilities to COVID-19 across New Zealand. While some major cities were highlighted many areas also occurred outside of the major cities in smaller communities, which also typically have less access to healthcare and fewer resources. This study has generated data that may help mitigate potential inequality in our response to the COVID-19 pandemic, or indeed for future pandemics

Investigating change in the food environment over 10 years in urban New Zealand: A longitudinal and nationwide geospatial study

Background: While it is likely that changing food environments have contributed to the rise in obesity rates, very few studies have explored historical trends in the food environment with little, if any, consideration at a nationwide level. This longitudinal, nationwide, and geospatial study aims to examine change over time in proximity to food environments in all urban areas of New Zealand from 2005 to 2015. Method: This study used high quality food outlet data by area-level deprivation within the three largest urban areas of Auckland, Christchurch and Wellington. We hypothesise that distance and travel time by car to supermarkets and fast-food outlets will have decreased over time with the most notable decreases in distance and time occuring in the most deprived areas of urban New Zealand. Change in major chain “fast-food” and “supermarket” outlets as identified by Territorial Authorities between 2005 and 2015 was analysed through the use of multilevel regression models. Results: Findings show a decrease in distance and time to both fast-food outlets and supermarkets. The biggest decrease in distance for supermarkets was seen in the most deprived areas. Conclusion: Our findings contrast and add to previous evidence to demonstrate how changes in the food environment are not uniform, varying by area-level deprivation and by city with more equitable access to supermarkets occurring over time