Effect of PM_2.5 exposure on circulating fibrinogen and IL-6 levels: A systematic review and meta-analysis

Ambient fine particulate matter (PM_2.5) pollution poses a great threat on global health. Previous studies have reported that PM_2.5 regulates circulating fibrinogen and IL-6 levels in the development of cardiovascular and respiratory disease. However, the correlation between PM_2.5 exposure and both biomarkers remains inconsistent.

We searched related articles through PubMed, Web of Science and ScienceDirect. Random effects model was used to obtain a pooled estimate effect of both biomarkers as PM_2.5 concentration increased by every 10 μg/m³. Meta-regression analysis, sensitivity analysis and publication bias test were conducted to evaluate the heterogeneity, stability and reliability of this meta-analysis.

A total of 22 articles were included. Each 10 μg/m³ increase in PM_2.5 concentration was significantly correlated with a 1.76% increase in circulating fibrinogen level (95% CI: 0.38%-3.14%, P = 0.013) and a 4.66% increase in IL-6 level (95% CI: 1.14%-8.18%, P = 0.010). Subgroup analysis revealed that high-level PM_2.5 exposure had a more significant association with circulating IL-6 level (11.67%, 95% CI: 0.66%-22.69%, P = 0.038) than low-level exposure, but this association was not observed in fibrinogen (2.50%, 95% CI: -0.78%-5.77%, P = 0.135). Sensitivity analysis and publication bias test confirmed the stability of the results.

Circulating fibrinogen and IL-6 significantly increased with exposure to PM_2.5, may serve as promising biomarkers for PM_2.5-related adverse effects.