Does neighborhood context change the association between tree canopy and allostatic load? Findings from a large, nationally representative sample

<title>Abstract</title> <p> <bold>Background:</bold> Many studies find associations between neighborhood greenery and lower stress. However, few studies have explicitly examined biomarkers of stress or the specific neighborhood contexts in which this is true. <bold>Methods:</bold> The objective was to examine the cross-sectional relationship between residential tree canopy and allostatic load among US adults (n=40,307) in the National Health and Nutrition Examination Survey (NHANES), to determine whether relationships differ by neighborhood context and after adjustment for individual demographics. <bold>Results</bold> : We found that greater tree canopy was associated with lower allostatic load. We did not observe a difference in this benefit by rural/urban neighborhood status. We consistently found that those residing in more vulnerable neighborhoods, regardless of indicator, were associated with significant and larger benefits for allostatic load. The largest effect was detected for those living in high vulnerability minority status and language neighborhoods such that for every 20% increase in tree canopy in such neighborhoods, we would expect allostatic load scores for residents to drop by 0.08. <bold>Conclusion</bold> : In vulnerable neighborhoods and in both urban and rural areas where the association between higher tree canopy and lower allostatic load was detected, there may be opportunities for tree planting to lower stress. These findings offer new insights beyond individual-level moderation of the effect of nature on health. </p>