Multilevel Analyses of Green Space Availability and Ethnic Differences in Mental Health

<p dir="ltr"><b>Background:</b> With an estimated 1 in 4 people globally expected to experience a mental illness at some point in their lives, mental health concerns are a huge health burden. In addition to having negative emotional and social effects, mental health issues can have high financial costs. Mental health is influenced by several characteristics, such as genetics, environment, lifestyle, and social determinants. Country of birth, year of first arrival in Australia, having another language spoken at home and self-identified ancestry influence how people of multicultural backgrounds perceive their mental health or access to mental health interventions. Exposure to higher levels of green space has been linked to better mental health outcome.</p><p dir="ltr"><b>Aim:</b> This thesis aims to generate new insights on the persistence of ethnic differences in mental health and urban greening as a potential part of a population-level solution. This aim can be achieved by assessing the green space availability amongst different ethnic groups, also evaluating the differences in mental health. This study explores the complex connections between the distribution of green spaces in urban environments among various ethnic groups and the mental health implications of those links. The first objective is to evaluate the extent of ethnic differences in green space availability. The second objective is to evaluate the ethnic differences in mental health from the dataset. The third objective is to analyse the relationship between the ethnic differences in green space and ethnic differences in mental health.</p><p dir="ltr"><b>Method:</b> Using multilevel logistic regression models, the study examines distribution patterns based on a number of variables that describe ethnicity, which are country of birth, spoken languages at home, year of first arrival in Australia, and self-identified ancestry. In order to investigate ethnic disparities in the availability of green space, percentages of parkland, tree canopy, and open grass within a 1.6 km road network distance from home were linked to 110,233 participants in the Sax Institute’s 45 and Up Study baseline survey living in three cities in Australia namely, Sydney, Newcastle, and Wollongong. Then, adjusted multilevel logistic regressions were used to examine odds of insufficient green space and mental health. Self-identified ancestries were examined on a total of 85520 people living in Wollongong, Newcastle, and Sydney. Then to investigate whether ethnic differences in green space availability influence, ethnic differences in mental health, four measures of mental health were used. Prevalence of psychological distress, emotional problems and doctor diagnosed depression or anxiety were extracted from the 45 and UP study and the fourth is use of antidepressant medications, which was from the pharmaceutical benefits scheme. Other covariates used in the multilevel regression analyses were extracted from the 45 and up study.</p><p dir="ltr"><b>Results:</b> The results show that different ethnic groups in places like Sydney, Newcastle, and Wollongong consistently lack access to enough green space. The research highlights the necessity of focused urban planning and policies, offering significant perspectives to the discussion on environmental justice in the Australian setting. Compared to participants born in Australia, those born in Italy (OR=1.22; 95%CI=1.02-1.46), Lebanon (OR=1.57; 95%CI=1.15-2.15), Vietnam (OR=1.38; 95%CI=1.05-1.81), or China (OR=1.23; 95%CI=1.03-1.47) had higher odds of insufficient parkland, . Migrants arriving in Australia after 1966 (e.g. 1996-2008 OR=1.18; 95%CI=1.04-1.34) and those speaking a language other than English also had higher odds of insufficient parkland (OR=1.09; 95%CI=1.03-1.15). In contrast, odds of insufficient tree canopy were lower among participants born Germany (OR=0.76; 95%CI=0.63-0.92), Italy (OR=0.76; 95%CI=0.63-0.92), Lebanon (OR=0.49; 95%CI=0.34-0.71), the Philippines (OR=0.59; 95%CI=0.45-0.77), China (OR=0.83; 95%CI=0.70-0.99), and India (OR=0.68; 95%CI=0.53-0.87) compared to those born in Australia. Odds of insufficient tree canopy were also lower for those who moved to Australia after 1966 or who spoke a non-English language at home.</p><p dir="ltr">Odds of insufficient open grass were higher for participants born in China, migrants between 1996 and 2008, and those speaking a language other than English at home. Analyses of ancestry suggest that comparing with the Australian ancestry, people with Irish and Maltese ancestry have lower odds of insufficient tree canopy. The Irish ancestry groups observed higher likelihood of insufficient parkland together with the Polish, English and Chinese ancestry groups (Chinese ancestry, OR=1.96 (1.19; 3.22), English, OR=1.07 (1.01; 1.13)), Irish, OR=1.07 (1.001; 1.15) and Polish, OR=1.42 (1.04; 1.94)). Open grass was generally similarly distributed across all the ancestries except for Chinese and German, who had consistently higher likelihood of insufficient open grass in their residential neighbourhoods than those of Australian ancestry.</p>