Urban green space and mental well-being of Aotearoa New Zealand adolescents: A path analysis

Background: Growing evidence shows the positive influence of neighbourhood green space on mental well-being among adults through multiple health behaviours, but similar studies are lacking for adolescents. Methods: Data were drawn from the 2019 wave of the Youth2000 survey series in Aotearoa, New Zealand with secondary school students (aged 10-19 years) from the city of Tamaki Makaurau, Auckland. Emotional well-being was measured with the World Health Organization-5 Well-being Index, and depressive symptoms were assessed using the Reynolds Adolescent Depression Scale-short form. Neighbourhood green space was assessed using three different measures: percentage of green space, Normalised Difference Vegetation Index (NDVI) and the distance to nearest green space from place of residence. Exposure areas of these measures were calculated using Euclidean buffers of 100m, 300m, 800m and 1600m around participants’ meshblock residential addresses. Three mediating (physical activity, social cohesion, sleep) and ten control variables (in adjusted models) were included in path analysis to test the direct and indirect relationships between green space and adolescent mental well-being. Results: In unadjusted models, percentage of green space had a negative relationship with emotional well-being, and inconsistent effects of NDVI were detected in different buffers. Minor indirect effects of physical activity and sleep were also found. Depressive symptoms and emotional well-being were more strongly related to other individual and neighbourhood factors (e.g., neighbourhood deprivation). After adjusting for control variables, no significant associations of green space with adolescent depressive symptoms and emotional well-being were identified. Conclusions: Urban neighbourhood green space does not appear to be a dominant factor contributing to adolescent mental well-being through physical activity, social cohesion and sleep. Appropriate individual and environmental control variables are needed to take into consideration in future studies that explore the green space-mental well-being relationships in adolescents.