Nature-based interventions for older adults: a systematic review of intervention types and methods, health effects and pathways

Background Nature-based interventions (NBIs) may support older adults’ health and well-being, but it remains unclear which interventions are most effective, for whom and in which contexts. The existing Wilkie and Davinson framework explains the pathways between NBIs and health outcomes but underemphasises the effects of environmental qualities. Therefore, the study aims to critically examine existing NBIs and their associated health outcomes, with a focus on identifying the environmental qualities and pathways that are either facilitating or impeding. Methods The review sought 16 databases for any nature-based interventions aimed at enhancing health outcomes where participants are older adults aged ≥65. The Mixed Methods Appraisal Tool assessed risk of bias. Narrative synthesis was used for result presentation. Results Of 6143 articles retrieved, 84 studies were included. Participants were primarily community dwelling without specific conditions. Most studies were quantitative experiments. Interventions were predominantly multicomponent, with restoring psychological capacities as the most common pathway. Spiritual, behavioural and socioecological changes were identified. Some health mechanisms were specific to outdoor interventions, but indoor interventions showed comparable outcomes. Conclusions The study predominantly included community-dwelling participants without specific health conditions, potentially limiting the generalisability of findings to older adults with multimorbidity or those in alternative living environments. Multicomponent interventions challenged direct associations between pathways and outcomes. Results extend existing frameworks by identifying spiritual, behavioural and socioecological benefits. Limited detailing of environmental qualities warrants further research to associate them with specific health outcomes. Registration The protocol was registered on PROSPERO (CRD42024496114).