Year

2020

Degree Name

Doctor of Philosophy

Department

School of Health and Society

Abstract

Background: The challenges of demographic and epidemiological transition around the world have created the need for ageing-friendly cities. Urban green spaces (UGS) are considered to be an important health and wellbeing resource, the role of which can be expanded to include the promotion of social and active ageing. There is accumulating evidence on the positive association between the quantity and quality of UGS and reduced risk of different types of noncommunicable and chronic diseases (NCDs) often associated with ageing. UGS is found to be associated with reduced risk of NCDs through multiple pathways including engaging in physical activities (PA) and increased social interaction. There is also evidence, as yet inconsistent, on the moderating effect of socioeconomic circumstances on these associations. A problem in the available evidence is that more than 90% of the evidence is geographically skewed to high-income and western countries (HICs). In addition, very few studies so far conducted have particularly focused on the role of UGS on the outdoor recreation activities of the ageing population. Therefore, this PhD study explores the extent to which inequitable distribution and quality of neighbourhood green spaces are associated with the level of outdoor recreational activities in multiple and geodemographically diverse cities.

Methods: The research design is principally based on five interrelated research questions which start with a systematic scoping review on the current evidence from the low and middleincome countries on the UGS and health research. To answer the subsequent research questions, both primary and secondary observational data collection was undertaken in a highincome, ‘Western’ city (Sydney, Australia), a high-income Asian city (Singapore) and a low and the middle-income city (Dhaka, Bangladesh). The study used a geographic information system (GIS) based UGS data and observation auditing tool to measure UGS quantity and quality respectively. The quantity of UGS was measured by calculating fixed boundary-based UGS availability and flexible boundary-based UGS accessibility. UGS quality data were collected by using an adapted version of the CPAT (Community Park Auditing Tool). The author also collected data on different types of use of UGS by people using a systematic observation tool adapted from SOPARC (System for Observing Play and Recreation in Communities). The socioeconomic circumstances together with the share of the ageing population (defined as aged 60 and above in Sydney and Singapore and as aged 50 and above in Dhaka) measured at the neighbourhood scale were used as potential moderators to analyse the inequity of UGS quantity and quality. Depending on the nature of outcome variables, multiple regression and Poisson regression modelling techniques were used at different stages of the research.

Results: The 22 studies were found from 11 LMICs through the systematic scoping review following PRISMA guidelines. Compared to the existing evidence-based in HICs, this review found fewer types and numbers of health aspects to relate to UGS exposures. While heterogeneous results were previously reported in the HIC based studies, the association was consistently positive with mental health, wellbeing and self-reported health aspects in the LMIC contexts except in one study. The similarity was found with HIC in regards to the reported association between UGS and physical health.

To understand whether UGS is evenly distributed across the case cities, the investigation of UGS quantity (measured by availability and accessibility) in this research found an inconsistent pattern of the socioeconomic inequity in the three case cities. Socioeconomic circumstances were found to have a strong positive association with the UGS availability in Sydney, whereas the association was significantly negative in Dhaka. In Singapore, this association was positive but statistically not significant. The percentage of the ageing population within a neighbourhood appeared to be independently associated with higher amount of UGS in Sydney and lower amount in Singapore. In these cities, the proportion of the ageing population is already higher than Dhaka. Accessibility measures were not associated with the socioeconomic circumstances except in Dhaka, where a strong negative association between socioeconomic circumstances and accessibility index was observed. The percentage of the ageing population showed a significant non-linear association with PWD only in Singapore. The population density was found to be an important predictor of UGS distribution in all the three cities. The population density was negatively associated with the UGS availability and accessibility in the medium density neighbourhoods of Sydney. While high accessibility was positively associated with high density in Singapore, it was negatively associated in Dhaka.

After scoring the UGS quality within a standard scale and classifying the quality of sample UGS into the high, moderate and poor categories, most of the high-quality UGSs were found in Singapore compared to Sydney and Dhaka. On the other hand, there was no high-quality UGS in Dhaka. The UGS quality score in Singapore was significantly higher and significantly lower in Dhaka compared to Sydney. When the individual quality domain was modelled, the UGS in Singapore had statistically significant higher scores in the accessibility, safety, and landscape quality domain than Sydney. On the other hand, activity space score in Dhaka is significantly lower than in Sydney. Availability of ageing friendly features such as bike routes, fitness stations, useable benches, picnic facilities, trail and absence of incompatibility issues (e.g. poor maintenance) were significantly higher in Singapore than two other cities. Based on our sample data, socioeconomic inequity of the UGS quality inconsistently found a tendency of having higher quality UGS in the advantaged communities within all the three cities. Especially, inequities within the cities were found more in the amenities and landscape quality domains. There is no direct or moderating effect of neighbourhood ageing profile found on the UGS quality. The largeness of the UGS was found to be an important predictor of UGS quality except in Singapore, where the size of the UGS did not confound the quality score.

Further investigations suggest that the ageing relevant total quality of the UGS was associated with sedentary and walking activities after adjusting the differences of cities. Sedentary and walking types of activities were significantly associated with only safety scores when individual quality domains were considered. On the other hand, vigorous activities of the ageing population had a statistically significant association with ageing relevant accessibility score, safety score and landscape quality score in the unadjusted models. The analysis ‘within city’ suggested that the ageing population in advantaged neighbourhoods with a higher percentage of the ageing population tend to participate more in different activities in Sydney and Dhaka, but not in Singapore.

Discussions: The inequity in the UGS quantity and quality was resulted from differences in urban planning processes as well as how the UGS measures in each city were computed. These findings suggest that neighbourhood UGS quality is associated with different level of recreation activities, though not in a similar way everywhere nor every aspect of the quality is equally important. However, some of the results were counterintuitive. For example, the negative association between activity space score and vigorous activities and vigorous activities in Singapore; and the negative association between safety score and level of vigorous activities in Dhaka. Also, the socioeconomic inequity, as found in the UGS quantity and quality is not universal and these differences in part driven by the differences in the urban planning and public health promotion realm. The study findings also suggest that there is room for improving UGS quality, revitalising existing UGS for the promotion of social and active ageing. Especially, the evidence from Singapore suggests that strong commitment and careful urban planning can reduce inequality of health-promoting resources like parks and open spaces while keeping balance between population density and supplying quality UGS.

This thesis is unavailable until Wednesday, March 03, 2021

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Unless otherwise indicated, the views expressed in this thesis are those of the author and do not necessarily represent the views of the University of Wollongong.