Nature contact and general health: Testing multiple serial mediation pathways with data from adults in 18 countries.

The role of neighbourhood nature in promoting good health is increasingly recognised in policy and practice, but consistent evidence for the underlying mechanisms is lacking. Heterogeneity in exposure methods, outcome measures, and population characteristics, little exploration of recreational use or the role of different types of green or blue space, and multiple separate mediation models in previous studies have limited our ability to synthesise findings and draw clear conclusions. We examined multiple pathways linking different types of neighbourhood nature with general health using a harmonised international sample of adults. Using cross-sectional survey data from 18 countries (n = 15,917), we developed a multigroup path model to test theorised pathways, controlling for sociodemographic variables. We tested the possibility that neighbourhood nature (e.g. greenspace, inland bluespace, and coastal bluespace) would be associated with general health through lower air pollution exposure, greater physical activity attainment, more social contact, and higher subjective well-being. However, our central prediction was that associations between different types of neighbourhood nature and general health would largely be serially mediated by recent visit frequency to corresponding environment types, and, subsequently, physical activity, social contact, and subjective well-being associated with these frequencies. Several subsidiary analyses assessed the robustness of the results to alternative model specifications as well as effect modification by sociodemographics. Consistent with this prediction, there was statistical support for eight of nine potential serial mediation pathways via visit frequency which held for a range of alternative model specifications. Effect modification by financial strain, sex, age, and urbanicity altered some associations but did not necessarily support the idea that nature reduced health inequalities. The results demonstrate that across countries, theorised nature-health linkages operate primarily through recreational contact with natural environments. This provides arguments for greater efforts to support use of local green/blue spaces for health promotion and disease prevention.

Nature versus urban hiking for Veterans with post-traumatic stress disorder: a pilot randomised trial conducted in the Pacific Northwest USA.

OBJECTIVES: To evaluate feasibility and acceptability of a group-based nature recreation intervention (nature hiking) and control condition (urban hiking) for military Veterans with post-traumatic stress disorder (PTSD). DESIGN AND SETTING: A pilot randomised controlled trial conducted in the US Pacific Northwest. PARTICIPANTS: Veterans with PTSD due to any cause. INTERVENTIONS: Twenty-six participants were randomised to a 12-week intervention involving either six nature hikes (n=13) or six urban hikes (n=13). PRIMARY AND SECONDARY OUTCOME MEASURES: Feasibility was assessed based on recruitment, retention and attendance. Questionnaires and postintervention qualitative interviews were conducted to explore intervention acceptability. Questionnaires assessing acceptability and outcomes planned for the future trial (eg, PTSD symptoms) were collected at baseline, 6 weeks, 12 weeks (immediately after the final hike) and 24 weeks follow-up. RESULTS: Of 415 people assessed for eligibility/interest, 97 were interested and passed preliminary eligibility screening, and 26 were randomised. Mean completion of all questionnaires was 91% among those in the nature hiking group and 68% in those in the urban hiking group. Over the course of the intervention, participants in the nature and urban groups attended an average of 56% and 58%, respectively, of scheduled hikes. Acceptability of both urban and nature hikes was high; over 70% reported a positive rating (ie, good/excellent) for the study communication, as well as hike locations, distance and pace. Median PTSD symptom scores (PTSD Checklist-5) improved more at 12 weeks and 24 weeks among those in the nature versus urban hiking group. CONCLUSIONS: This pilot study largely confirmed the feasibility and acceptability of nature hiking as a potential treatment for Veterans with PTSD. Adaptations will be needed to improve recruitment and increase hike attendance for a future randomised controlled trial to effectively test and isolate the ways in which nature contact, physical activity and social support conferred by the group impact outcomes. TRIAL REGISTRATION NUMBER: NCT03997344.

Results from an 18 country cross-sectional study examining experiences of nature for people with common mental health disorders.

Exposure to natural environments is associated with a lower risk of common mental health disorders (CMDs), such as depression and anxiety, but we know little about nature-related motivations, practices and experiences of those already experiencing CMDs. We used data from an 18-country survey to explore these issues (n = 18,838), taking self-reported doctor-prescribed medication for depression and/or anxiety as an indicator of a CMD (n = 2698, 14%). Intrinsic motivation for visiting nature was high for all, though slightly lower for those with CMDs. Most individuals with a CMD reported visiting nature ≥ once a week. Although perceived social pressure to visit nature was associated with higher visit likelihood, it was also associated with lower intrinsic motivation, lower visit happiness and higher visit anxiety. Individuals with CMDs seem to be using nature for self-management, but 'green prescription' programmes need to be sensitive, and avoid undermining intrinsic motivation and nature-based experiences.