The impact of transport, housing, and urban development interventions on older adults' mobility: A systematic review of experimental and quasi-experimental studies.

Background: Age-friendly cities and communities aim to enhance and preserve the functional abilities of older adults. This systematic review assesses the impact of interventions in transportation, housing, and urban development on the mobility of older adults. Methods: We systematically searched MEDLINE, Embase, CINAHL, Scopus, PsycINFO, and SocINDEX up to July 2022 to identify studies that evaluated the impact of transportation, housing, and urban development interventions on older adults' mobility. Only randomised controlled trials and quasi-experimental studies with control groups were included to establish a causal relationship between interventions and mobility outcomes. Findings: We included a total of 15 studies, of which six were randomised controlled trials. Included studies were conducted in high-income settings and employed diverse metrics to assess mobility outcomes. Among housing interventions, three studies examined the impact of assistive technology within home environments for frail older adults. Two of these interventions maintained functional status without improvement, while the third showed a significant decline in outcomes, with the control group faring even worse. Public transport interventions, focused on enhancing mobility through educational initiatives and policy revisions, consistently produced positive outcomes. Interventions related to driving training for older adults, including in-class and on-road assessments, demonstrated beneficial effects. Results from studies evaluating urban design interventions were more varied, with some enhancing mobility by making public spaces more accessible for older adults and others yielding mixed results following infrastructure changes. Interpretation: Interventions in the built environments of older adults, specifically targeting transportation, housing and urban development, have the potential to enhance mobility and related outcomes according to rigorously designed quantitative evaluations. Due to heterogeneity in how mobility is conceptualised in the literature, greater harmonisation in measurement of mobility would help us understand how the social and built environment contribute to maintaining and improving mobility in older adults. Funding: World Health Organization.