Metals and polycyclic aromatic hydrocarbons co-exposure: Amino acid omics insights on blood glucose homeostasis

Previous studies have reported a relationship between exposure to metals and polycyclic aromatic hydrocarbons (PAHs) and blood glucose levels, but whether the mechanisms are mediated by amino acids remains to be elucidated. We conducted a three-wave repeated measurement study involving 201 elderly individuals (aged ≥ 50 years) from five communities in Beijing, China. We simultaneously measured eight metals in both blood and urine, six monohydroxy PAHs in urine, and 23 amino acids in blood. Linear mixed-effects and sparse partial least squares models were used to evaluate the individual effects, and Bayesian kernel machine regression was employed to mixture effects. Mediation analysis was further used to explore whether amino acids mediators mediate the association. We observed significant associations of selenium and strontium with increased blood glucose. Additionally, blood copper, urinary nickel, as well as urinary 1 + 9 hydroxyphenanthrene, were associated with irregular blood glucose regulation. Moreover, we found that amino acids such as leucine, proline, and alanine may mediate the associations. This study is the first to investigate the effect of metals and PAHs on blood glucose homeostasis, while also exploring the mediating role of amino acids, offering new insights into the impact of metals and PAHs on blood glucose regulation.