You are here:
Associations between Neighborhood Natural Features and Depression: A U.S. National Analysis
Citation:
Tsai, WeiLun, R. Silva, S. Prince, F. Cochran, D. Rosenbaum, M. Nash, A. D'Aloisio, L. Jackson, A. Neale, M. Mehaffrey, T. Buckley, AND D. Sandler. Associations between Neighborhood Natural Features and Depression: A U.S. National Analysis. World Conference on Forests for Public Health, Athens, Attica, GREECE, May 08 - 11, 2019.
Impact/Purpose:
To communicate recent eco-health research findings from an individual-level analysis using the NIEHS national Sisters Study database. As conference participants are leading international experts on forests, green space and human health, participation will be a highly effective means to broadcast our latest research for application and to network with leaders in the field.
Description:
INTRODUCTION: Globally, over 300 million people are estimated to suffer from depression. In the United States, approximately 16.2 million adults aged 18 and above have had at least one major depressive episode, and the prevalence in females is almost twice that in males. A growing body of research shows that natural features such as trees, gardens, and water are associated with better mental health; however, these relationships are underexplored at the national level in the United States. Much of the existing evidence draws from spatially-restricted samples which may not be generalizable. In addition, it is not clear if different types of natural features at varying neighborhood extents have the same effects on mental health, and if these effects are constant across geographic regions. This ongoing study explores relationships between depressive symptoms and natural features within multiple landscape buffers around residences. METHOD: Depression was evaluated based on the 10-item Center for Epidemiologic Studies Depression Scale (CES-D-10) collected by the Sister Study, National Institute of Environmental Health Sciences. The cohort comprises 50,884 women aged 35 – 74 years old across the United States and Puerto Rico, and provides measures in multiple dimensions including physical, mental, and social health, sociodemographic factors, and lifestyles. Depression was defined as having a CES-D 10 score greater than ten. Tree canopy and a broader measure of naturalness, non-impervious cover, were derived using percent tree canopy and percent impervious cover at 30m resolution from the U.S. Multi-Resolution Landcover Characteristics Consortium. Euclidean buffers were applied at 250, 500, and 1000m to represent nearby, near, and distant neighborhoods from participants’ residential addresses, and non-overlapping buffers were generated for the areas between 250 – 500 and between 500 – 1000 meters. Logistic regression was applied with adjusting for potential confounders and stratification to examine differences by geographic region. RESULTS: Preliminary results include that both tree canopy and non-impervious cover are associated with lower odds of being depressed at all buffer sizes; the protective effects are stronger at greater neighborhood extents. In addition, the effects of non-impervious cover are triple those of tree canopy alone. However, significant associations were not observed within the non-overlapping buffers. Disparate results were observed across regions. CONCLUSIONS: Neighborhood natural elements may benefit mental health through multiple pathways, including supporting aesthetics and biodiversity that may enhance outdoor venues for physical activity, engagement with nature, and social interaction, all of which can improve mental health. The observed statistical effects of natural features on depression are continuous and greater with increasing distances from homes. Further work will investigate effects of natural features measured at one-meter resolution, with finer classification of vegetation types, as well as their patterns within the built environment, to better understand critical neighborhood design elements to improve mental health. This abstract has been reviewed and approved for submission by the U.S. Environmental Protection Agency. Its contents do not necessarily reflect the views and policies of the Agency.