Enabling Health Outcomes of Nature-based Interventions: A Systematic Scoping Review

Abstract

AbstractBackgroundThe burden of poor mental health and non-communicable disease is increasing, and some practitioners are turning to nature to provide the solution. Nature-based interventions could offer cost-effective solutions that benefit both human health and the environment by reconnecting individuals with nature. Importantly, the relative success of these interventions depends upon the accessibility of green and blue spaces, and the way in which people engage with them.Aims and ObjectivesA scoping review was conducted to establish the evidence base for nature-based interventions as a treatment for poor mental and physical health, and to assess whether and how enablers influence engagement with natural outdoor environments.MethodsThis scoping review followed the PRISMA-ScR and the associated Cochrane guidelines for scoping reviews. A literature search was performed across five databases and the grey literature, and articles were selected based on key inclusion and exclusion criteria. Exposure was the active engagement with natural environments. The primary outcome was mental health and the secondary outcome was physical health, both defined using established metrics. All data was extracted to a charting table and reported as a narrative synthesis.ResultsThe final analysis included thirty-nine studies. Most of these focused on green spaces, with only five dedicated to blue spaces. Six nature-based health intervention types were identified: (i) educational interventions, (ii) physical activity in nature, (iii) wilderness therapy, (iv) leisure activities, (v) gardening and (vi) changes to the built environment. Of the 39 studies, 92.2% demonstrated consistent improvements across health outcomes when individuals engaged with natural outdoor environments (NOEs). Furthermore, of 153 enablers that were found to influence engagement, 78% facilitated engagement while 22% reduced engagement. Aspects such as the sense of wilderness, accessibility, opportunities for physical activity and the absence of noise/ air pollution all increased engagement.ConclusionFurther research is still needed to establish the magnitude and relative effect of nature- based interventions, as well as to quantify the compounding effect of enablers on mental and physical health. This must be accompanied by a global improvement in study design. Nevertheless, this review has documented the increasing body of heterogeneous evidence in support of NBIs as effective tools to improve mental, physical, and cognitive health outcomes. Enablers that facilitate greater engagement with natural outdoor environments, such as improved biodiversity, sense of wilderness and accessibility, as well as opportunities for physical activity and an absence of pollution, will likely improve the impact of nature-based interventions and further reduce public health inequalities.