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Using health effect biomarkers to characterize benefits of urban green spaces
Citation:
Egorov, A., S. Griffin, R. Converse, J. Styles, E. Sams, A. Wilson, R. Baldauf, V. Isakov, L. Jackson, AND Tim Wade. Using health effect biomarkers to characterize benefits of urban green spaces. International Society of Exposure Science (ISES), RTP, NC, October 15 - 19, 2017.
Impact/Purpose:
This abstract is part of the EPA-organized symposium at the ISES 2017 meeting entitled “Pathways and mechanisms linking exposure to the natural environment with health and well-being benefits”. The abstract summarized results of an ongoing joint inter-laboratory research on health-promoting community-level characteristics. It supplements other ORD research on green spaces under the Sustainable and Healthy Communities research program. An inter-laboratory (NHEERL and NERL) team of researchers conducted an observational study in the Durham-Chapel Hill metropolitan area involving analysis of serum and saliva samples for multiple biomarkers of health effect. The results demonstrate that greater amount of vegetation near residence is linked with reduced risk of chronic stress-related physiological dysregulation known as allostatic load. This biomarker-based information on subclinical health benefits of urban green spaces is novel. The findings are important because allostatic load has been linked with increased risks of cardiovascular diseases, mental disorders, diabetes, and premature death. Ongoing activities include collaboration with NERL and NRMRL to use EnviroAtlas and C-LINE tools to characterize exposure to vegetated land cover and traffic air pollution, and to assess health benefits of green barriers.
Description:
Greater availability of urban green spaces has been linked to improved mental and physical health, and reduced mortality. Relative contributions of hypothesized pathways to improved health, such as relaxation and stress alleviation, enhanced physical activity, reduced exposure to air pollution, noise and heat, and beneficial exposure to natural allergens and microbes, remain to be characterized. The objective of an ongoing research project at US EPA is to characterize subtle biological changes associated with long-term exposure to green space using a panel of biomarkers of metabolic, neuroendocrine and immune function, and to produce novel information on pathways to health. A pilot cross-sectional study in the Durham-Chapel Hill, NC area used 1-meter resolution data on trees and herbaceous vegetation within 500 m of residences derived from the U.S. EPA EnviroAtlas land cover dataset. Eighteen health effect biomarkers were measured in serum or saliva samples from more than 200 adults. Regression models controlled for demographic covariates and spatial autocorrelation. Increased proportion of vegetated land cover (trees and grass) was associated with: 1) a highly significant reduction of a composite biomarker-based measure of physiological dysregulation known as allostatic load; 2) reduced odds of having potentially unhealthy levels of individual biomarkers associated with chronic inflammation and chronic stress; and 3) reduced odds of previously diagnosed depression. Ongoing analysis aims to characterize residential exposures of study participants to air pollutants and noise from local traffic using the Community LINE Source Model (C-LINE) developed by U.S. EPA and the University of North Carolina, and to assess potential effects of green barriers and green spaces in mitigating detrimental effects of gaseous and particulate air pollution on health biomarkers. Further research efforts aim to evaluate associations between various measures of exposure to urban greenery, stress, physical activity, exposure to air pollutants, human microbiome, allostatic load and susceptibility to infectious and non-communicable diseases in prospective settings. This abstract does not represent EPA policy.