Unraveling the Molecular Links between Fine Particulate Matter Exposure and Early Birth Risks in African American Mothers: A Metabolomics Study in the Atlanta African American Maternal-Child Cohort.

In the United States, African Americans (AA) are disproportionately exposed to elevated levels of ambient fine particulate matter (PM) while suffering from the highest rates of early births. To elucidate the largely unknown underlying mechanism, we analyzed serum metabolomics from 330 participants in the Atlanta AA Maternal-Child Cohort and performed high-throughput mediation analysis to identify intermediate metabolites and pathways linking PM to early births. Energy-metabolism-related metabolites (carnitine and adenosine triphosphate), along with lysoPE(20:3) and acetylcysteine, were both associated with PM exposure and elevated early birth risks. Perturbations in protein digestion and absorption and aromatic amino acid (phenylalanine, tyrosine, and tryptophan) metabolism may potentially mediate the associations between PM and early births. We identified significant indirect effects of cortexolone (Proportion mediated: -11.8%) and lysoPE(20:3) (9.4%) in mediating the relationship between PM and early births. Our findings might aid in early birth prevention among AA communities by providing novel insights into the underlying biological mechanism.