Green space exposure and cardiovascular health: a systematic review of mediation pathways

Background

The association between green space exposure and cardiovascular disease (CVD) is well established, but the pathways underlying this relationship remain insufficiently understood. Mediation analysis can help identify intermediate mechanisms explaining how exposure to green spaces influences cardiovascular health. This systematic review synthesizes evidence from observational studies using formal mediation analyses to clarify these pathways.

Methods

A systematic review was conducted building on a previous review (Liu et al., 2022). We searched PubMed, Web of Science, and Embase for studies published between 2022 and May 2024. Eligible studies included observational research assessing green space exposure, cardiovascular outcomes, and mediation analyses. Data were extracted on study design, exposure metrics, mediators, and health outcomes.

Results

From 2,138 identified records, 14 studies were included. Most were cross-sectional, with fewer prospective cohort studies. Green space exposure was mainly measured using Normalized Difference Vegetation Index (NDVI), with limited use of Leaf Area Index (LAI) and percentage green area. Cardiovascular disease was the most common outcome (90.9%), followed by stroke (45.5%), myocardial infarction (36.4%), heart failure (18.2%), and cardiovascular mortality (36.4%). Physical activity, air pollution, BMI, and traffic noise were the most studied mediators, with inconsistent evidence of mediation effects across studies.

Conclusions

Green space exposure may influence cardiovascular health through multiple pathways, but evidence on specific mediators remains heterogeneous. Strengthening understanding of these mechanisms is essential to support nature-based solutions and to guide urban planning strategies that maximize the health benefits of green spaces.

Key messages

• Green space exposure benefits cardiovascular health through multiple pathways, but key mediators like activity, air pollution and noise show inconsistent results.

• Better understanding of how green space affects cardiovascular risk is needed to improve urban planning for healthier cities.