Duration-sensitive association between air pollution exposure and changes in cardiometabolic biomarkers: Evidence from a predominantly African American cohort

Background: Ambient fine particulate matter (PM_2.5) exposure has been related to cardiometabolic diseases, but the underlying biological pathways remain unclear at the population level.

Objective: To investigate the effect of PM_2.5 exposure on changes in multiple cardiometabolic biomarkers across different exposure durations.

Method: Data from a prospective cohort study were analyzed. Ten cardiometabolic biomarkers were measured, including ghrelin, resistin, leptin, C-peptide, creatine kinase myocardial band (CK-MB), monocyte chemoattractant protein-1 (MCP-1), tumor necrosis factor alpha (TNF-alpha), N-terminal pro B-type natriuretic peptide (NT-proBNP), troponin, and interleukin-6 (IL-6). PM_2.5 levels across exposure durations from 1 to 36 months were assessed. Mixed effect model was used to estimate changes in biomarker levels against 1 μg/m³ increase in PM_2.5 level across different exposure durations.

Results: Totally, 641 participants were included. The average PM_2.5 exposure level was 9 μg/m³. PM_2.5 exposure was inversely associated with ghrelin, and positively associated with all other biomarkers. The magnitudes of these associations were duration-sensitive and exhibited a U-shaped or inverted-U-shaped trend. For example, the association of resistin were β = 0.05 (95% CI: 0.00, 0.09) for 1-month duration, strengthened to β = 0.27 (95% CI: 0.14, 0.41) for 13-month duration, and weakened to β = 0.12 (95% CI: -0.03, 0.26) for 24-month duration. Similar patterns were observed for other biomarkers except for CK-MB, of which the association direction switched from negative to positive as the duration increased. Resistin, leptin, MCP-1, TNF-alpha, and troponin had a sensitive exposure duration of nearly 12 months. Ghrelin and C-peptide were more sensitive to longer-term exposure (>18 months), while NT-proBNP and IL-6 were more sensitive shorter-term exposure (<6 months).

Conclusion: PM_2.5 exposure was associated with elevated levels in cardiometabolic biomarkers related to insulin resistance, inflammation, and heart injury. The magnitudes of these associations depended on the exposure duration. The most sensitive exposure durations of different biomarkers varied.