A multi-scalar perspective on health and urban housing: An umbrella review

With more than half the world’s population living in cities, understanding how the built environment impacts human health at different urban scales is crucial. To be able to shape cities for health, an understanding is needed of planetary health impacts, which encompass the human health impacts of human-caused disruptions on the Earth’s natural ecosystems. This umbrella review maps health evidence across the spatial scales of the built environment (building; neighbourhood; and wider system, including city, regional and planetary levels), with a specific focus on urban housing. Systematic reviews published in English between January 2011 and December 2020 were searched across 20 databases, with 1176 articles identified and 124 articles screened for inclusion. Findings suggests that most evidence reports on health determinants at the neighbourhood level, such as greenspace, physical and socio-economic conditions, transport infrastructure and access to local services. Physical health outcomes are also primarily reported, with an emerging interest in mental health outcomes. There is little evidence on planetary health outcomes and significant gaps in the research literature are identified. Based on these findings, three potential directions are identified for future research. POLICY RELEVANCE Evidence about local built environment determinants of health have focused to date on physical health outcomes and the neighbourhood level; there is also significant evidence about mental health outcomes and greenspace. Future research can strengthen understanding of mental health outcomes across all scales and determinants of the built environment; investigate more robustly planetary health outcomes; and provide additional evidence at the building and wider urban system level, especially in relation to low-income settings, vulnerable groups and communicable disease. There is limited discussion of implications for policymaking and economic evaluations of health interventions, i.e. the cost of intervention versus health outcomes. Urban health interventions have focused to date on treating the effects of health conditions; however, there is potential for constructive interventions in the built environment (at various scales) which improve health and/or reduce environmental health risks if the policy focus is on dealing with the causes of health conditions.