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The Green Heart Project: Objectives, Design and Methods

Published Article

Kentucky

Publication date: December 16, 2024

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The Green Heart Project is a community-based clinical trial in Louisville, KY, studying how urban greening impacts health. Since 2018, researchers measured pollution, cardiovascular risk and stress in diverse residents, planted 8,000+ trees, and continue tracking long-term effects on community well-being and environment.

Subject Tags

  • Community-based conservation
  • Equitable conservation
  • Social Sciences

Abstract

The Green Heart Project is a controlled, community-based clinical trial to evaluate the effects of increasing greenery on community health. The study was initiated in 2018 in a low-to-middle-income residential area of nearly 30,000 racially diverse residents in Louisville, KY. Community engagement was maintained throughout the project, with feedback integrated into its design and implementation. Based on land use, demographics, and greenness in the area, we designated 8 paired clusters of demographically- and environmentally matched “target” (T) and adjacent “control” (C) areas (total of 16 clusters). Levels of ultrafine particles, ozone, and nitrogen oxides were measured in each cluster. In-person exams were conducted for 735 participants in Wave 1 (2018-2019) and 545 participants in Wave 2 (2021). Blood, urine, nail, and hair samples were collected to evaluate cardiovascular risk, inflammation, stress, and pollutant exposure. Demographic and psychosocial data were collected as well. Cardiovascular function was assessed by measuring arterial stiffness and flow-mediated dilation. After Wave 2, more than 8,000 mature, mostly evergreen, trees and shrubs were planted in the T clusters. Post planting data were collected during Wave 3 (2022) from 561 participants. We plan to follow changes in area characteristics and participant health to evaluate the long-term impact of the greening intervention.

Citation

Bhatnagar, A., Keith, R., Yeager, R., Riggs, D., Sears, C., Bucknum, B., Smith, T., Fleischer, D., Chandler, C., Walker, K.L. and Hart, J.L., 2024. The Green Heart Project: objectives, design, and methods. American Journal of Epidemiology, p.kwae458.

https://doi.org/10.1093/aje/kwae458

TNC Authors