Effects of urban greenspace on time to major adverse cardiovascular events among women with breast cancer in the US: Insights from the Greater Milwaukee, WI Area.

BACKGROUND

Cardiovascular (CV) disease (CVD) remains a significant concern among breast cancer (BC) survivors, particularly following potentially cardiotoxic treatments, such as anthracyclines and anti-HER2 drugs, which increase the risk of major adverse CV events (MACE). Social determinants of health (SDOH) and environmental factors influence health outcomes, including those related to CVD. Urban greenspace has been associated with CV and cancer-related health benefits, yet its specific impact on MACE among BC survivors remains unknown.

OBJECTIVE

This study aims to investigate the association between urban greenspace and time to first MACE incidence among individuals with BC after being treated with cardiotoxic therapies in the greater Milwaukee, WI area.

METHODS

A retrospective cohort study was conducted using electronic medical records from the Froedtert Health System, linked to the National Death Index. Cox proportional hazards regression models were used to assess the association between percent tree canopy cover and MACE-specific hazards, adjusting for sociodemographic, clinical, and neighborhood-level factors.

RESULTS

Among the 849 women included, 44.6 % experienced a MACE. Adjusted models indicated an 18 % reduction in MACE-specific hazard (HR: 0.82, 95 % CI: 0.70, 0.96) and a 20 % reduction in MACE-specific hazard (HR: 0.80, 95 % CI: 0.67, 0.97) for women in the second and third quartiles of percent tree canopy cover, respectively, compared to the women in the first (lowest) quartile. However, we did not observe a risk difference for women living in the fourth quartile of tree canopy. Racial/ethnic disparities in greenspace exposure and MACE incidence were evident, with Non-Hispanic Black (NHB) women having a lower proportion living in areas with the highest tree canopy cover and a higher MACE incidence (61.9 %) compared to Non-Hispanic White (NHW) women (41.6 %), who had the highest proportion residing in areas within the 4th quartile of tree canopy cover.

DISCUSSION

Our findings suggest that urban tree canopy is associated with time to incident MACE among BC survivors receiving cardiotoxic treatments. These results underscore the importance of considering socioenvironmental factors in CardioOncology care and highlight the benefits of greenspace in mitigating CV complications among individuals with BC. Future research should delve into individual lifestyle and behavioral factors, environmental factors, and biological mechanisms that may underlie these associations. Additionally, longitudinal studies should be conducted to evaluate greenspace-based interventions for BC survivors, aiming to advance precision CardioOncology interventions. Observed racial/ethnic disparities in MACE incidence underscore the urgent need for equity-focused interventions addressing greenspace access and MACE-related disparities.