Blood environmental chemical exposure levels among adults with chronic kidney disease: a cross-sectional NHANES study

BACKGROUND: The kidney plays a central role in eliminating xenobiotics, making individuals with impaired kidney function vulnerable to chemical accumulation. We aimed to evaluate the relationship between kidney function and circulating levels of blood environmental chemicals in a nationally representative sample. METHODS: Data were obtained from the National Health and Nutrition Examination Survey (NHANES) (2003-2016). Among 71 058 participants, 33 673 were included after excluding children, and individuals with missing kidney function or chemical measurements. Kidney function status was ascertained using the estimated glomerular filtration rate and dialysis status. We analysed serum or blood concentrations of six chemical classes: per- and polyfluoroalkyl substances, brominated flame retardants, heavy metals (lead, mercury, cadmium), volatile organic compounds, organochlorine pesticides, and polychlorinated biphenyls. We used survey-weighted linear regression models to estimate adjusted geometric mean ratios of chemical concentrations across kidney function categories. RESULTS: Compared to individuals with normal kidney function, those with severe chronic kidney disease (CKD) had significantly higher concentrations of lead (geometric mean ratio = 1.48; 95% confidence interval [CI]: 1.33-1.64) and cadmium (geometric mean ratio = 1.34; 95% CI: 1.24-1.45), but lower levels of perfluorooctane sulfonic acid (geometric mean ratio = 0.26; 95% CI: 0.16-0.43). Similar trends were observed among dialysis recipients. CONCLUSIONS: Individuals with severe CKD exhibit distinct chemical profiles characterised by elevated heavy metals and reduced per- and polyfluoroalkyl substance levels. Further research into the clinical implications of environmental exposures in CKD populations is warranted.