Abstract P104: Geospatially Varying Relationships of Green and Blue Spaces With Biomarkers of Stress and Cardiometabolic Risk in Racially and Ethnically Diverse Children
Authors: de Brito Junia N , Mu Lan , Tate Allan D , Fertig Angela , Pereira Mark A , Berge Jerica M 
Published: May 2024

Introduction:
Neighborhood green (e.g., parks) and blue (e.g., lakes) spaces have been associated with reduced stress and cardiometabolic risk (CMR), but research is limited in socially vulnerable urban communities affected by structural racism and redlining. This study explored the spatial correlation between green and blue spaces and cortisol levels, BMI percentile, waist circumference (WC), pulse, and systolic (SBP) and diastolic blood (DBP) pressure in a sample of racially/ethnically diverse children.

Methods:
We used cross-sectional data from the Family Matters cohort study, consisting of 1307 racially/ethnically diverse families with children (age 7±1.5 yrs). Participant addresses were matched to the US 2010 Census tract attributes. We used 246 sample locations across 149 census tracts in the 7-county Twin Cities, MN, metro area. Green and blue spaces were retrieved from the Twin Cities Metropolitan Council. Hair cortisol (chronic stress biomarker), BMI, WC, pulse, SBP and DBP were objectively measured in a subsample of 246 children. We used Decision Tree and Geographically Weighted Regression (GWR) to examine the spatially varying associations of CDC’s Social Vulnerability Index (SVI) and green and blue spaces (independent variables) with biomarkers of stress and CMR (dependent variables). SVI reflects four themes: socioeconomic status, household composition and disability, racial and ethnic minority status and language, and housing type and transportation.

Results:
Northwest Minneapolis was identified as a hotspot for elevated cortisol, BMI, and WC, while east St. Paul was a hotspot for elevated BMI and WC. Decision trees indicated that green and blue spaces explain variation in accumulated cortisol after tract socioeconomic status and racial and ethnic minority status. GWR revealed nonuniform relationships with the highest explanatory power in high social vulnerability hotspots. GWR’s R
2
for cortisol (0.07), BMI (0.14), and WC (0.14) were driven by hotspots where local R
2
was 2-5 times stronger than areas not identified as hotspots indicating robust geographical variations in the northern areas (areas of high social vulnerability) and distance from green and blue spaces. Patterns were inconsistent for pulse, SBP, and DBP.

Conclusions:
The spatially varying relationships of green and blue spaces with biomarkers of stress and CMR in children were heterogeneous, possibly indicating different mechanisms across biomarkers and geographical areas. Higher cortisol levels, BMI percentile, and WC in northern Twin Cities areas may reflect the legacy of structural racism and redlining, which have resulted in inequitable use of green and blue spaces for minoritized communities. Future interventions co-developed with local communities to improve green and blue spaces’ access and use, as well as to reduce disparities in stress and CMR, are needed to advance health equity.