Impact of Ambient Air Pollution on Cardiovascular Diseases in Low- and Lower-Middle-Income Countries: A Systematic Review and Meta-Analysis

Key findings from this study

This research indicates that:

• Short-term exposure to PM2.5 and PM10 increased cardiovascular mortality and hospital admission in low- and lower-middle-income countries, with effect sizes of 0.53% and 1.68% per 10 μg/m3 respectively.
• Nitrogen dioxide exposure was associated with a 0.66% increase in cardiovascular outcomes per 10 μg/m3.
• Evidence linking ambient air pollution to cardiovascular disease in low- and lower-middle-income countries remains substantially limited relative to research conducted in higher-income settings.

Overview

This systematic review and meta-analysis examined the association between ambient air pollution exposure and cardiovascular disease outcomes in low-income and lower-middle-income countries. The analysis synthesized evidence from 48 studies addressing a research gap, as air pollution research predominantly occurs in higher-income settings despite greater disease burden in resource-limited regions.

Methods and approach

Researchers searched PubMed and Global Health databases for studies examining associations between gaseous pollutants (SO2, NO2, CO, O3) and particulate matter (PM2.5, PM10) with cardiovascular mortality and hospital admission. Risk of bias assessment evaluated outcome validity, exposure measurement quality, and confounder adjustment. A random-effects model standardized short-term exposure estimates to 10 μg/m3 increments across 22 studies contributing to meta-analysis.

Results

Short-term PM2.5 exposure increased combined cardiovascular mortality and hospital admission by 0.53% (95% CI: 0.31%-0.75%) per 10 μg/m3 increment. PM10 exposure produced a 1.68% increase (95% CI: 0.17%-3.21%) per 10 μg/m3. Nitrogen dioxide demonstrated a 0.66% increase (95% CI: 0.36%-0.97%) per 10 μg/m3. Across the screened literature, 48 studies met inclusion criteria, with 22 providing quantifiable relative risk estimates suitable for pooled analysis. The meta-analysis demonstrated positive associations between multiple ambient air pollutants and cardiovascular hospital admissions and mortality outcomes in low- and lower-middle-income settings.

Implications

The findings establish that ambient air pollution represents a measurable cardiovascular risk in resource-limited settings, though the evidence base remains substantially smaller than in higher-income countries. This disparity limits precision in burden estimates and policy guidance for regions experiencing severe air pollution with constrained healthcare infrastructure. Targeted epidemiological research in underrepresented geographic regions is necessary to characterize long-term exposure effects and validate short-term associations in diverse pollution environments and healthcare contexts.

Scope and limitations

This summary is based on the study abstract and available metadata. It does not include a full analysis of the complete paper, supplementary materials, or underlying datasets unless explicitly stated. Findings should be interpreted in the context of the original publication.