High-Resolution Measures of Natural Environments and Mental Health Outcomes in the Nurses' Health Studies

Abstract

The biophilia hypothesis and psychoevolutionary theory suggest that exposure to nature might be linked to better mental health outcomes. Recent studies have observed associations between exposure to nature and mental health; however, many of these studies have used coarse vegetation indices to assess exposure to nature. In addition, as far as the authors are aware, no prior study has examined the relationship between nature and positive psychological constructs, such as optimism.Using high-resolution, aerial photography-based data on natural environments from EPA EnviroAtlas datasets across 18 urban areas, we examined the relationship between residential exposure to natural environments (including green space, tree cover, and proximity to parks) and validated self-reported measures of doctor-diagnosed depression, depressive symptoms, doctor-diagnosed anxiety, social integration, and optimism in over 12,000 female participants in the Nurses’ Health Study and Nurses’ Health Study II cohorts located in communities across the entire United States. Analyses were adjusted for age, race educational attainment of each participant and her husband, smoking, alcohol consumption, alterative healthy eating index, BMI, and census-tract median family income, home value, and population density. We tested effect modification by individual and area-level socioeconomic status (SES), race, physical activity, population density, and region.Using extremely high-resolution data on natural environments, this study will build the evidence base for nearby nature as a potential environmental intervention to improve psychological well-being. Municipalities have engaged in tree planting and other landscape interventions as part of climate change mitigation and adaptation efforts, and this study provides vital data on nature as a co-benefit for mental health.