Do PFAS and certain metals contribute to reduced kidney function?

The kidney serves as a primary route for the elimination of various persistent environmental chemicals, and extensive population data suggest a significant correlation between higher concentrations of these substances and reduced renal function.

Population and clinical evidence

Epidemiological data, primarily from large-scale studies such as NHANES, consistently show that elevated body burdens of per- and polyfluoroalkyl substances (PFAS) and heavy metals are associated with lower estimated glomerular filtration rates (eGFR).

• PFAS exposure: Individual compounds including PFOA, PFOS, and PFNA, as well as complex mixtures, demonstrate a negative association with eGFR. Reported beta coefficients range from -0.27 to -0.52, indicating a clear trend toward decreased filtration capacity as serum levels rise.
• Heavy metals: Lead (Pb), cadmium (Cd), and arsenic (As) show strong inverse correlations with kidney health. Blood lead levels, for instance, have a reported correlation coefficient of approximately 0.318 with lower eGFR and are linked to increased odds of chronic kidney disease (CKD).
• Emerging metals: While nickel (Ni) has been associated with proteinuria, other metals like tungsten (W) and platinum (Pt) also show emerging evidence of renal impact, though population-wide longitudinal data are less extensive than for lead or cadmium.

Mechanistic explanations

The interaction between these substances and the kidney involves specific molecular transport systems and filtration physicals.

• Active transport: PFAS compounds like PFNA are handled by organic anion transporters (OATs) in the proximal tubule. OAT1 and OAT3 facilitate the uptake from the blood into tubule cells for secretion, while OAT4 is involved in apical reabsorption, which can extend the substance's half-life in the body.
• Filtration and secretion: Soluble metal complexes (e.g., nickel) and nanoparticles (typically <6 nm in diameter) are cleared via glomerular filtration. Platinum compounds often interact with both OATs and organic cation transporters (OCTs), highlighting the dual role of the kidney as both an excretion pathway and a site of potential accumulation and toxicity.

Bottom line

Scientific evidence supports a clear association between higher body burdens of PFAS and heavy metals and reduced eGFR. This relationship is driven by the kidney's role in active secretion and filtration of these toxins, which can lead to renal strain and increased risk of dysfunction over time.