Karen Witten

Neighbourhoods and health: a GIS approach to measuring community resource accessibility

Objective: Recent studies suggest an association between the contextual attributes of neighbourhoods and the health status of residents. However, there has been a scarcity of studies that have directly measured the material characteristics of neighbourhoods theorised to have an impact on health and health inequalities. This paper describes the development of an innovative methodology to measure geographical access to a range of community resources that have been empirically linked to health. Geographical information systems (GIS) were applied to develop precise measures of community resource accessibility for small areas at a national scale. Design: Locational access to shopping, education, recreation, and health facilities was established for all 38 350 census meshblocks across New Zealand. Using GIS, distance measures were calculated from the population weighted centroid of each meshblock to 16 specific types of facilities theorised as potentially health related. From these data, indices of community resource accessibility for all New Zealand neighbourhoods were constructed. Results: Clear regional variations in geographical accessibility to community resources exist across the country, particularly between urban and rural areas of New Zealand. For example, the average travel time to the nearest food shop ranged from less than one minute to more than 244 minutes. Noticeable differences were also apparent between neighbourhoods within urban areas. Conclusions: Recent advances in GIS and computing capacity have made it feasible to directly measure access to health related community resources at the neighbourhood level. The construction of access indices for specific community resources will enable health researchers to examine with greater precision, variations in the material characteristics of neighbourhoods and the pathways through which neighbourhoods impact on specific health outcomes.

The contextual effects of neighbourhood access to supermarkets and convenience stores on individual fruit and vegetable consumption

Background: It is often suggested that neighbourhood access to food retailers affects the dietary patterns of local residents, but this hypothesis has not been adequately researched. We examine the association between neighbourhood accessibility to supermarkets and convenience stores and individuals’ consumption of fruit and vegetables in New Zealand. Methods: Using geographical information systems, travel times from the population-weighted centroid of each neighbourhood to the closest supermarket and convenience store were calculated for 38 350 neighbourhoods. These neighbourhood measures of accessibility were appended to the 2002–3 New Zealand Health Survey of 12 529 adults. Results: The consumption of the recommended daily intake of fruit was not associated with living in a neighbourhood with better access to supermarkets or convenience stores. Similarly, access to supermarkets was not related to vegetable intake. However, individuals in the quartile of neighbourhoods with the best access to convenience stores had 25% (OR 0.75, 95% CI 0.60% to 0.93%) lower odds of eating the recommended vegetable intake compared to individuals in the base category (worst access). Conclusion: This study found little evidence that poor locational access to food retail provision is associated with lower fruit and vegetable consumption. However, before rejecting the commonsense notion that neighbourhood access to fruit and vegetables affects personal consumption, research that measures fruit and vegetable access more precisely and directly is required.

Neighbourhood access to open spaces and the physical activity of residents: A national study

OBJECTIVE Increasing population levels of physical activity is high on the health agenda in many countries. There is some evidence that neighbourhood access to public open space can increase physical activity by providing easier and more direct access to opportunities for exercise. This national study examines the relationship between travel time access to parks and beaches, BMI and physical activity in New Zealand neighbourhoods. METHODS Access to parks and beaches, measured in minutes taken by a car, was calculated for 38,350 neighbourhoods nationally using Geographic Information Systems. Multilevel regression analyses were used to establish the significance of access to these recreational amenities as a predictor of BMI, and levels of physical activity and sedentary behaviour in the 12,529 participants, living in 1178 neighbourhoods, of the New Zealand Health Survey 2002/3. RESULTS Neighbourhood access to parks was not associated with BMI, sedentary behaviour or physical activity, after controlling for individual-level socio-economic variables, and neighbourhood-level deprivation and urban/rural status. There was some evidence of a relationship between beach access and BMI and physical activity in the expected direction. CONCLUSIONS This study found little evidence of an association between locational access to open spaces and physical activity.

A national study of the association between neighbourhood access to fast-food outlets and the diet and weight of local residents

Differential locational access to fast-food retailing between neighbourhoods of varying socioeconomic status has been suggested as a contextual explanation for the social distribution of diet-related mortality and morbidity. This New Zealand study examines whether neighbourhood access to fast-food outlets is associated with individual diet-related health outcomes. Travel distances to the closest fast-food outlet (multinational and locally operated) were calculated for all neighbourhoods and appended to a national health survey. Residents in neighbourhoods with the furthest access to a multinational fast-food outlet were more likely to eat the recommended intake of vegetables but also be overweight. There was no association with fruit consumption. Access to locally operated fast-food outlets was not associated with the consumption of the recommended fruit and vegetables or being overweight. Better neighbourhood access to fast-food retailing is unlikely to be a key contextual driver for inequalities in diet-related health outcomes in New Zealand.

The societal costs and benefits of commuter bicycling: simulating the effects of specific policies using system dynamics modeling

Background: Shifting to active modes of transport in the trip to work can achieve substantial co-benefits for health, social equity, and climate change mitigation. Previous integrated modeling of transport scenarios has assumed active transport mode share and has been unable to incorporate acknowledged system feedbacks. Objectives: We compared the effects of policies to increase bicycle commuting in a car-dominated city and explored the role of participatory modeling to support transport planning in the face of complexity. Methods: We used system dynamics modeling (SDM) to compare realistic policies, incorporating feedback effects, nonlinear relationships, and time delays between variables. We developed a system dynamics model of commuter bicycling through interviews and workshops with policy, community, and academic stakeholders. We incorporated best available evidence to simulate five policy scenarios over the next 40 years in Auckland, New Zealand. Injury, physical activity, fuel costs, air pollution, and carbon emissions outcomes were simulated. Results: Using the simulation model, we demonstrated the kinds of policies that would likely be needed to change a historical pattern of decline in cycling into a pattern of growth that would meet policy goals. Our model projections suggest that transforming urban roads over the next 40 years, using best practice physical separation on main roads and bicycle-friendly speed reduction on local streets, would yield benefits 10–25 times greater than costs. Conclusions: To our knowledge, this is the first integrated simulation model of future specific bicycling policies. Our projections provide practical evidence that may be used by health and transport policy makers to optimize the benefits of transport bicycling while minimizing negative consequences in a cost-effective manner. The modeling process enhanced understanding by a range of stakeholders of cycling as a complex system. Participatory SDM can be a helpful method for integrating health and environmental outcomes in transport and urban planning. Citation: Macmillan A, Connor J, Witten K, Kearns R, Rees D, Woodward A. 2014. The societal costs and benefits of commuter bicycling: simulating the effects of specific policies using system dynamics modeling. Environ Health Perspect 122:335–344; http://dx.doi.org/10.1289/ehp.1307250

Neighborhood built environment and transport and leisure physical activity: findings using objective exposure and outcome measures in New Zealand.

Background: Evidence of associations between neighborhood built environments and transport-related physical activity (PA) is accumulating, but few studies have investigated associations with leisure-time PA. Objective: We investigated associations of five objectively measured characteristics of the neighborhood built environment—destination access, street connectivity, dwelling density, land-use mix and streetscape quality—with residents’ self-reported PA (transport, leisure, and walking) and accelerometer-derived measures of PA. Methods: Using a multicity stratified cluster sampling design, we conducted a cross-sectional survey of 2,033 adults who lived in 48 New Zealand neighborhoods. Multilevel regression modeling, which was adjusted for individual-level (sociodemographic and neighborhood preference) and neighborhood-level (deprivation) confounders, was used to estimate associations of built environment with PA. Results: We found that 1-SD increases in destination access, street connectivity, and dwelling density were associated with any versus no self-reported transport, leisure, or walking PA, with increased odds ranging from 21% [street connectivity with leisure PA, 95% confidence interval (CI): 0%, 47%] to 44% (destination accessibility with walking, 95% CI: 17%, 79%). Among participants who self-reported some PA, a 1-SD increase in street connectivity was associated with a 13% increase in leisure PA (95% CI: 0, 28%). SD increases in destination access, street connectivity, and dwelling density were each associated with 7% increases in accelerometer counts. Conclusions: Associations of neighborhood destination access, street connectivity, and dwelling density with self-reported and objectively measured PA were moderately strong, indicating the potential to increase PA through changes in neighborhood characteristics.

Is neighborhood access to health care provision associated with individual-level utilization and satisfaction?

OBJECTIVE To explore whether travel time access to the nearest general practitioner (GP) surgery (which is equivalent to U.S. primary care physician [PCP] office) and pharmacy predicts individual-level health service utilization and satisfaction. DATA SOURCES GP and pharmacy addresses were obtained from the New Zealand Ministry of Health in 2003 and merged with a geographic boundaries data set. Travel times derived from these data were appended to the 2002/03 New Zealand Health Survey (N=12,529). STUDY DESIGN Multilevel logistic regression was used to model the relationship between travel time access and five health service outcomes: GP consultation, blood pressure test, cholesterol test, visit to pharmacy, and satisfaction with latest GP consultation. DATA COLLECTION/EXTRACTION Travel times between each census meshblock centroid and the nearest GP and pharmacy were calculated using Geographical Information System. PRINCIPAL FINDINGS When travel times were long, blood pressure tests were less likely in urban areas (odds ratio [OR] 0.75 [0.59-0.97]), GP consultations were less likely in rural centers (OR 0.42 [0.22-0.78]) and pharmacy visits were less likely in highly rural areas (OR 0.36 [0.13-0.99]). There was some evidence of lower utilization in rural areas. CONCLUSIONS Locational access to GP surgeries and pharmacies appears to sometimes be associated with health service use but not satisfaction.

The impacts of a school closure on neighbourhood social cohesion: narratives from Invercargill, New Zealand.

We propose that, beyond their educational function, schools can serve as catalysts for community participation, social cohesion and the vitality of neighbourhoods. The paper explores the impacts of a school closure on families in an urban neighbourhood in Invercargill, New Zealand. The highest urban depopulation rate in the country has had implications for the viability of Invercargill schools. We present a qualitative study of narratives gathered during an interview-based study of the closure of Surrey Park School. Our analysis highlights the impact of school closure for low-income families and more generally reflects on the place of schools in contributing to social cohesion and the broadly defined health of a community.

Understanding the Relationship between Activity and Neighbourhoods (URBAN) Study: research design and methodology

BackgroundBuilt environment attributes are recognized as being important contributors to physical activity (PA) engagement and body size in adults and children. However, much of the existing research in this emergent public health field is hindered by methodological limitations, including: population and site homogeneity, reliance on self-report measures, aggregated measures of PA, and inadequate statistical modeling. As an integral component of multi-country collaborative research, the Understanding the Relationship between Activity and Neighbourhoods (URBAN) Study seeks to overcome these limitations by determining the strengths of association between detailed measures of the neighborhood built environment with PA levels across multiple domains and body size measures in adults and children. This article outlines the research protocol developed for the URBAN Study.Methods and designThe URBAN Study is a multi-centered, stratified, cross-sectional research design, collecting data across four New Zealand cities. Within each city, 12 neighborhoods were identified and selected for investigation based on higher or lower walkability and Māori demographic attributes. Neighborhoods were selected to ensure equal representation of these characteristics. Within each selected neighborhood, 42 households are being randomly selected and an adult and child (where possible) recruited into the study. Data collection includes: objective and self-reported PA engagement, neighborhood perceptions, demographics, and body size measures. The study was designed to recruit approximately 2,000 adults and 250 children into the project. Other aspects of the study include photovoice, which is a qualitative assessment of built environment features associated with PA engagement, an audit of the neighborhood streetscape environment, and an individualized neighborhood walkability profile centered on each participants residential address. Multilevel modeling will be used to examine the individual-level and neighborhood-level relationships with PA engagement and body size.DiscussionThe URBAN Study is applying a novel scientifically robust research design to provide urgently needed epidemiological information regarding the associations between the built environment and health outcomes. The findings will contribute to a larger, international initiative in which similar neighborhood selection and PA measurement procedures are utilized across eight countries. Accordingly, this study directly addresses the international priority issues of increasing PA engagement and decreasing obesity levels.

Neighbourhood Destination Accessibility Index: a GIS tool for measuring infrastructure support for neighbourhood physical activity

The sharp increase in obesity in recent years has prompted researchers to examine the various pathways through which urban built environments influence population-level physical activity. Walking access to everyday destinations is one such pathway. This paper describes a measure of pedestrian access to neighbourhood destinations. Using eight domains of neighbourhood destinations (education, transport, recreation, social and cultural, food retail, financial, health, and other retail) we developed a GIS-based ‘Neighbourhood Destination Accessibility Index’ (NDAI) for four New Zealand cities. We found that the intensity of neighbourhood destination opportunities varied considerably among cities and between neighbourhoods within cities. Further, access to neighbourhood infrastructural support tends to be better in more socially deprived places. Potential explanations for the sociospatial distribution of neighbourhood destinations in New Zealand cities include historical processes of residential and economic development and infrastructural investment.