Abstract WP215: Residential Greenspace Protects Against Stroke

Abstract

Introduction: Greenspace, both residential and public, is associated with improved outcomes for a variety of medical conditions. Its effect on stroke incidence is not as well established. In this study, we sought answers to three questions: Does an increase in residential greenspace, as measured by the Normalized Difference in Vegetation Index (NDVI), lessen the odds of stroke? Is socioeconomic status (SES), as measured by the Area Deprivation Index (ADI), correlated with NDVI? Is proximity to a public park a risk factor for stroke? Methods: This is a matched (1:4) case-controlled study. The cohort was adult patients admitted to Aurora St Luke’s Medical Center in Milwaukee, WI between 2016 and 2018. Non-stroke controls (N=328,868) were matched to stroke cases (N=2336) on known cardiovascular risk factors after excluding patients with prior stroke, addresses outside of Milwaukee County, and residences within 250 meters of a water feature. The matched study sample included 5870 patients (stroke cases=1174 and non-stroke controls = 4696). The mean NDVI within a 250 meter radius around the patients’ residence and distance to a public park were calculated using satellite imagery and geographical information systems (GIS) software. State decile and national percentile ADI were obtained from the Neighborhood Atlas. A Spearman’s rank-order correlation determined the relationship between the NDVI, state and national ADI, and proximity to parks. Conditional logistic regression was used to examine the relationship between a stroke event and NDVI, ADI, and proximity to public parks. Results: We found a protective association between higher NDVI values and stroke (OR = 0.33, 95% CI = 0.111-0.975, p = 0.045). There was a negative correlation between NDVI and national (rs(5870) = -.548, p < .001) and state (rs(5870) = -.550, p < .001) ADI, both statistically significant. There was no association between proximity to parks and stroke (OR = 1.00, 95% CI = 1.000 – 1.000, p = 0.456). Conclusion: An increase in residential NDVI significantly decreases the odds of stroke. Distance to a public park did not impact the odds of stroke. These findings have implications for city planning and mitigation of social disparities in health.