Search

The aim of this research is to analyse the spatial epidemiology of Type 2 Diabetes Mellitus (T2DM) and investigate associations with the built environment in urban New Zealand. Data on T2DM was sourced from the New Zealand Virtual Diabetes Register (2016), and data on environmental variables sourced from the Ministry for Primary Industries and Territorial Authorities (2013-2016). Novel measures of the built environment using an enhanced two-step floating catchment area model were established using data on fast food outlets, takeaways, dairy/convenience stores, supermarkets and fruit/vegetable stores. Rates of T2DM per 1000 population and standardised morbidity ratios were computed and visualised for all urban areas. Getis Ord was used to assess spatial clustering, and Bayesian modelling was used to understand associations between T2DM and environmental variables. Results indicate that T2DM is influenced by demographic factors, spatially clustered and associated with accessibility to environmental exposures. Health-promoting resources, such as fruit/vegetable stores, were shown to have a consistently protective effect on T2DM while those considered detrimental to health showed varying, and largely insignificant, associations. This is the first study in New Zealand to spatially quantify the effects of multiple environmental exposures on population level T2DM for all urban areas using a geospatial approach. It 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., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Background: Immunisation is a safe and effective way of protecting children and adults against harmful diseases. However, immunisation coverage of children is declining in some parts of New Zealand., Aim: Use a nationwide sample to first, examine the socioeconomic and demographic determinants of immunisation coverage and spatial variation in these determinants. Second, it investigates change in immunisation coverage in New Zealand over time., Methods: Individual immunisation records were obtained from the National Immunisation Register (NIR) (2005-2017; 4,482,499 events). We calculated the average immunisation coverage by year and milestone age for census area units (CAU) and then examined the immunisation coverage by selected socioeconomic and demographic determinants. Finally, local variations in the association between immunisation coverage and selected determinants were investigated using geographically weighted regression., Results: Findings showed a decrease of immunisation rates in recent years in CAUs with high immunisation coverage in the least deprived areas and increasing immunisation rates in more deprived areas. Nearly all explanatory variables exhibited a spatial variation in their association with immunisation coverage. For instance, the strongest negative effect of area-level deprivation is observed in the northern part of the South Island, the central-southern part of the North Island, around Auckland, and in Northland., Conclusion: Our findings show that childhood immunisation coverage varies by socioeconomic and demographic factors across CAUs. We also identify important spatial variation and changes over time in recent years. This evidence can be used to improve immunisation related policy in New Zealand., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Telephone triage is a health tool increasingly used to connect geographically distant populations. Such services are also utilised to address issues of Emergency Department (ED) overuse. New Zealand's tele-triage service, Healthline, has existed since 2001 but is yet to be the focus of analysis. This research sought to understand the role that travel time to ED had upon Healthline users' compliance with telephone advice. Additionally, the role of deprivation in Healthline (as a determinant of caller behaviour) was examined. Travel time to ED was found to influence the impact of Healthline advice upon callers but this was not confounded by deprivation. Those living closest to the ED were more likely to attend when advised to, and less likely to stay away if told to avoid the ED. Different time brackets showed stronger trends, suggesting that callers at varying distances from EDs may be more or less influenced by both travel time and Healthline advice., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

In this longitudinal study, we compare the effects of different types of relocation and level of affectedness on the incidence and relapse of mood and anxiety symptom treatments identified by publicly funded care or treatment one year before and one and two years after the '2011 Christchurch earthquake' in New Zealand. Based on a subset of Christchurch residents from differently affected areas of the city identified by area-wide geotechnical land assessments (no to severe land damage) 'stayers', 'within-city movers', 'out-of-city movers' and 'returners' were identified to assess the interaction effect of different levels of affectedness and relocation on the incidence and relapse of mood and anxiety symptom treatments over time. Health and sample information were drawn from the New Zealand Ministry of Health's administrative databases allowing us to do a comparison of the pre-/post-disaster treatment status and follow-up on a large study sample. Moving within the city and returning have been identified as general risk factors for receiving care or treatment for mood or anxiety symptoms. In the context of the 2011 Christchurch earthquake, moving within the city showed a protective effect over time, whereas returning was a significant risk factor in the first post-disaster year. Additionally, out-of-city movers from minor, moderately or severely damaged Christchurch's plain areas were identified as especially vulnerable two years post-disaster. Generally, no dose-response relationship between level of affectedness and mood or anxiety symptom treatments was identified, but the finding that similarly affected groups from the city's plain areas and the more affluent Port Hills showed different temporal treatment trends highlights the importance of including socio-economic status in exposure assessment. High-risk groups included females, older adults and those with a pre-existing mental illness. Consequently, mental health intervention programs should target these vulnerable groups, as well as out-of-city movers from affected areas in the long run., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Geographical inequalities in health are omnipresent with health and related behaviours typically worse in socioeconomically deprived places. However, this is not always true. Deprived places with unexpectedly good health outcomes, or what might be considered 'resilient' places, have been noted. Few studies have quantitatively examined resilience in neighbourhoods or investigated potential explanations for this resilience. This paper examines the paradox of low mortality despite high social deprivation in New Zealand neighbourhoods and considers possible neighbourhood characteristics that contribute to unanticipated positive health outcomes. Using area-level mortality (2005-2007) and socioeconomic data, we developed the Resilience Index New Zealand to quantify neighbourhood levels of resilience across the country. We then examined relationships between this measure and a suite of built, physical and social characteristics. We found that resilient places tended to be densely populated, urban areas. We observed gradients and increases/decreases in the most resilient groups in access to or levels of physical environment factors (environmental deprivation, safe drinking water, air quality) and unhealthy living infrastructure (alcohol and gambling outlets). Since these factors are amenable to change, these findings are the strongest evidence that such improvements may lower mortality in similarly deprived places. The social environment of resilient areas was characterised by high levels of incoming residents. We also found some surprising associations and observed U-shaped relationships for a number of the neighbourhood factors. Such findings suggest the need to develop a better proxy of community cohesion and a better understanding of the interactions between people and their neighbourhoods, rather than simply the presence of certain factors. We argue that this study has identified amenable neighbourhood characteristics and highlighted the importance of 'place-specific' resilience factors that may be effective in reducing mortality in some neighbourhoods, but be less effective in others., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

Epidemiological studies that examine the relationship between environmental exposures and health often address other determinants of health that may influence the relationship being studied by adjusting for these factors as covariates. While disease surveillance methods routinely control for covariates such as deprivation, there has been limited investigative work on the spatial movement of risk at the intraurban scale due to the adjustment. It is important that the nature of any spatial relocation be well understood as a relocation to areas of increased risk may also introduce additional localised factors that influence the exposure-response relationship. This paper examines the spatial patterns of relative risk and clusters of hospitalisations based on an illustrative small-area example from Christchurch, New Zealand. A four-stage test of the spatial relocation effects of covariate adjustment was performed. First, relative risks for respiratory hospitalisations from 1999 to 2004 at the census area unit level were adjusted for age and sex. In three subsequent tests, admissions were adjusted for annual exposure to particulate matter less than 10 microm in diameter (PM10), then for a deprivation index, and finally for both PM10 and deprivation. Spatial patterns of risk, disease clusters and cold and hot spots were generated using a spatial scan statistic and a Getis-Ord Gi* statistic. In all disease groups tested (except the control disease), adjustment for chronic PM10 exposure and deprivation modified the position of clusters substantially, as well as notably shifting patterns and hot/cold spots of relative risk. Adjusting for PM10 and/or for deprivation shifted clusters in a similar spatial fashion. In Christchurch, the resulting shift relocated the cluster from a purely residential area to a mixed residential/industrial area, possibly introducing new environmental exposures. Researchers should be aware of the potential spatial effects inherent in adjusting for covariates when considering study design and interpreting results.

Traditional approaches in environmental spatial epidemiology have relied on assessing postulated links between environmental pollution and ill health, often as a response to a perceived public health problem; clearly it may be necessary to go beyond this stage in order to establish the nature of potential causal mechanisms. Different disciplines approach this issue in different ways. Many toxicologists favour approaches based on air quality monitoring, where raised levels of candidate pollutants may subsequently generate hypotheses about adverse health effects. Epidemiologists, however, assess the health of a population and then look for an associated cause. This paper suggests that neither approach is completely satisfactory and that a combination of both is needed. If spatially referenced data are available for both health status and air quality, then geographical analysis is needed to examine possible links, by using techniques such as atmospheric dispersion modelling and Geographical Information Systems. We discuss the benefits and constraints of these approaches, using empirical examples of environmental epidemiology studies for northern England. Taking into account the problems involved in such studies, allied to the high costs incorporated, the paper asks the question: Are we searching for the impossible?