Green space exposure, mediators, and health in older adults: A systematic review

Rapid population ageing and increasing chronic disease burdens highlight the need to better integrate older adults' green space exposure into environmental and health impact assessment. However, current evidence is fragmented by inconsistent age definitions, reliance on static availability-based greenness metrics, and limited attention to mechanisms, vulnerability, and bias. Following PRISMA 2020 guidelines, we systematically searched Web of Science and Scopus and included 117 studies on green-space exposure and health among older adults. Exposure metrics were grouped within an accessibility-availability-visibility (A-A-V) framework and examined together with environmental modifying factors, behavioral pathways, and health outcomes; keyword co-occurrence and clustering were used to map research foci. NDVI-based availability indicators dominate, while accessibility (e.g. distance, network/time-based access, public transport, street connectivity) and visibility (e.g. street-level greenness, Green View Index) measures are inconsistently defined and applied. Near-home green space and tree canopy are linked to light-to-moderate physical activity and reduced heat, air pollution, and noise exposure, with reported benefits across multiple health domains. We identify major gaps, including scarce dynamic exposure assessment, limited distributional and age-specific equity analyses, and inconsistent risk-of-bias evaluation. We propose an A-A-V indicator framework that links measurable exposure metrics, pathways, and age-relevant health endpoints, offering a practical basis for integrating older adults' green space-related health into impact assessment and age-friendly urban planning.