Abstract
Background
Residential greenness is associated with multiple health benefits, yet its distribution across socioeconomic groups remains insufficiently synthesized, limiting understanding of environmental health inequalities.
Objectives
To quantify the magnitude and direction of the association between socioeconomic status (SES) and residential greenness, assess consistency across geographic regions, and identify research gaps.
Methods
We conducted a systematic review and meta-analysis of observational studies. PubMed, Web of Science, Scopus, and CINAHL were searched from inception to December 2025. Studies of predominantly urban populations (≥85%) assessing greenness using the Normalized Difference Vegetation Index (NDVI) were included. SES was defined by income and/or education. Two reviewers independently screened records, extracted data, and assessed quality using the Newcastle–Ottawa Scale. Random-effects models (DerSimonian and Laird) were used to pool standardized mean differences (SMD) and odds ratios (OR) with 95% confidence intervals (CI). Subgroup analyses by geographic region were conducted.
Results
Twenty-six studies (n = 9,411,596; 14 countries) were included. Higher income was associated with greater greenness (continuous NDVI: SMD=0.50; 95% CI: 0.31–0.69), as was higher education (SMD=0.34; 95% CI: 0.13–0.56). For categorical NDVI, higher income increased the likelihood of living in greener areas (OR = 1.54; 95% CI: 1.32–1.81), with a smaller effect for education (OR = 1.20; 95% CI: 1.06–1.35). No differences were observed across regions.
Conclusions
Socioeconomic inequalities are strongly associated with unequal distribution of residential greenness, particularly by income. These findings support equity-oriented urban planning to reduce environmental and health disparities.
Key messages
• Socioeconomic inequalities influence access to green spaces, with disadvantaged groups consistently exposed to fewer green environments, thereby exacerbating environmental and health disparities.
• Our findings highlight that greenness is unevenly distributed, favoring higher SES groups, underscoring the need for equitable urban planning to reduce social and health inequalities.