Nature prescriptions: a scoping review with a nested meta-analysis

Abstract

Background "Nature prescriptions" are gaining popularity as a form of social prescribing and in response to calls for sustainable healthcare. Our review and meta-analysis appraised evidence of effectiveness of nature prescriptions on various health outcomes. In doing so, we sought to determine the factors that are critical for the success of nature prescriptions, based on Social Cognitive Theory. Methods This is a scoping review with a nested meta-analysis for a subset of outcomes. Five databases were searched up to July 25, 2021. Randomised and non-randomised controlled studies featuring a nature prescription (i.e. an instruction or organised programme, by a health or social provider, to promote spending time in nature) are included. All health outcomes are eligible, but only key pre-specified outcomes are qualified for meta-analysis. Two reviewers independently conducted all steps of study selection; one reviewer conducted data collection and risk of bias assessment. Summary data was extracted from published reports for analysis. Random-effect models for meta-analysis were conducted using Review Manager 5.4.1. Findings We identified 86 unique studies (116 reports), of which 26 studies contributed data to meta-analysis. Compared to control, nature prescription programmes resulted in a greater reduction in systolic blood pressure (MD = -4.9mmHg [-9.6 to -0.1], I2=65%) and diastolic blood pressure (MD = -3.6mmHg [-7.4 to 0.1], I2=67%). They also had a moderate-to-large effect on depression scores (SMD=0.5 [0.2 to 0.8], I2=79%) and anxiety score (SMD=0.6 [0.1 to 1.2], I2=90%). Lastly, they resulted in a greater increase in daily step counts (MD = 900 steps [790-1010], I2=0%), but did not improve weekly time of moderate physical activities (MD = 25.9 minutes [-10.3 to 62.1], I2=53%). Most studies have moderate to high risk of bias, principally due to non-blinding nature of the interventions, small sample size and lack of analysis plan to rule out risks of bias. Interpretation Nature prescription programmes may provide cardiometabolic and mental health benefits and increase physical activity. Effective nature prescription programmes can select from a range of natural settings, activities and might be implemented via social and community channels, besides health providers. The Social Cognition Theory is useful in designing future nature prescription programmes.

Exploring the benefits of nature-based interventions in socio-economically deprived communities: a narrative review of the evidence to date

“… 47 NBIs are increasingly being used within health services in the form of nature prescriptions with evidence to suggest positive effects of nature prescriptions on depression and anxiety. 95 Given the potential benefits of NBIs on mental health outcomes, future research and public health initiatives should endeavour to evaluate the benefits of NBIs in contrast to current treatment options for individuals from socio-economically deprived communities who experience mental health-related difficulties.…”

Nature Rx: Nature prescribing in general practice

“…Unstructured nature prescribing was also assessed (eg recommending walks in local parks or national parks), with incentives such as free passes or motivators such as pedometers or exercise diaries. 1 A scoping review with nested meta-analysis of nature prescribing conducted by Nguyen et al 10 included randomised and non-randomised controlled studies of nature prescribing (86 studies in total). Compared with controls, nature prescription programs resulted in greater reductions in systolic blood pressure (mean difference [MD] -4.9 mmHg [95% CI: -9.6, -0.1 mmHg]; I 2 =65%) and diastolic blood pressure (MD -3.6 mmHg [95% CI: -7.4 to 0.1 mmHg]; I 2 =67%) after the intervention, showing that these programs may be an adjunct to pharmacotherapy.…”

“…11,12 The review by Nguyen et al showed how nature prescriptions led to greater increases in daily step counts (MD 900 steps [790, 1010]; I 2 =0%). 10 Physical activity in natural environments is also likely to result in less exposure to air pollution and heat.…”

“…Spending time in nature can offer other benefits apart from physical activity, including social connection and improvement in wellbeing indicators, such as reduced depression scores (standardised MD [SMD] 0.5 [0.2, 0.8]; I 2 =79%) and anxiety scores (SMD 0.6 [0.1, 1.2]; I 2 =90%). 1,10 Emerging evidence indicates that these psychological benefits may be closely entwined with restorative processes that ameliorate feelings of chronic loneliness. 13 Only one study has been conducted in general practice in Australia, in Adelaide.…”

Need and Interest in Nature Prescriptions to Protect Cardiovascular and Mental Health: A Nationally-Representative Study With Insights for Future Randomised Trials

“…by regulating air quality [5]), restores depleted cognitive capacities [6,7], alleviates stress [8], reduces loneliness [9][10][11] and encourages regular health behaviours such as physical activity [12,13]. Meta-analyses indicate interventions that enable people to spend more time in nature increase levels of physical activity and lower risks of depression, anxiety, and high blood pressure [14], providing a compelling and urgent case to support harnessing nature in health care [15,16].…”