Perfluorinated Chemicals as Emerging Environmental Threats to Kidney Health: A Scoping Review

Addressing health inequalities in diverse, rural communities: An unmet need

Research on rural health needs to represent the diverse demographics of these regions by carefully considering the distinct characteristics, inequities, and stressors occurring in rural communities. Drawing from our own findings and other empirical investigations examining diverse rural communities, we propose several considerations to guide future endeavors toward more inclusive rural health research. These include population-health assessment tools that consider minority stress and intervention strategies designed to reflect both the environmental and socio-cultural contexts of rural residents.

Renal function and isomers of perfluorooctanoate (PFOA) and perfluorooctanesulfonate (PFOS): Isomers of C8 Health Project in China

Perfluoroalkyl substances (PFASs) are widely-utilized synthetic chemicals commonly found in industrial and consumer products. Previous studies have examined associations between PFASs and renal function, yet the results are mixed. Moreover, evidence on the associations of isomers of PFASs with renal function in population from high polluted areas is scant. To help to address this data gap, we used high performance liquid chromatography-mass spectrometry to measure serum isomers of perfluorooctanoate (PFOA), perfluorooctanesulfonate (PFOS), and other PFASs from 1612 adults residing in Shenyang, China, and characterized their associations with estimated glomerular filtration rate (eGFR) and chronic kidney disease (CKD). Results showed that after adjusted for multiple confounding factors, most of the higher fluorinated PFASs, except for PFOA and PFDA, were negatively associated with eGFR and positively associated with CKD. Compared with linear PFOS (n-PFOS), branched PFOS isomers (Br-PFOS) were more strongly associated with eGFR (Br-PFOS; β = -1.22, 95%CI: 2.02, -0.42; p = 0.003 vs. n-PFOS; β = -0.16, 95%CI: 0.98, 0.65; p = 0.691) and CKD (Br-PFOS; OR = 1.27; 95% CI: 1.02, 1.58; p = 0.037 vs. n-PFOS; OR = 0.98; 95% CI: 0.80, 1.20; p = 0.834). In conclusion, branched PFOS isomers were negatively associated with renal function whereas their linear counterparts were not. Given widespread exposure to PFASs, potential nephrotoxic effects are of great public health concern, Furthermore, longitudinal research on the potential nephrotoxic effects of PFASs isomers will be necessary to more definitively assess the risk.

Perfluoroalkyl substances follow inverted U-shaped distributions across various stages of glomerular function: Implications for future research

Data (N = 6844) from National Health and Nutrition Examination Survey for US adults aged ≥ 20 years for the years 2007-2014 were analyzed to evaluate distributional characteristics of selected perfluoroalkyl substances (PFAS) - perfluorooctanoic acid (PFOA), perfluorooctane sulfonate (PFOS), perfluorodecanoic acid (PFDA), perfluorohexane sulfonate (PFHxS) and perfluorononanoic acid (PFNA) with declining glomerular function. The population was stratified according to the estimated glomerular filtration rates (eGFR) that accompany the stages of kidney disease, designated as glomerular function-1 (GF-1, eGFR>90 mL/min/1.73 m2); GF-2 (eGFR 60-89 mL/min/1.73 m2), GF-3A (eGFR 45-59 mL/min/1.73 m2), and GF-3B and 4 combined (eGFR 15-44 mL/min/1.73 m2). Unadjusted as well as adjusted geometric means for serum PFOA, PFDA, PFHxS, and PFNA increased as expected through stage GF-3A but decreased below the concentrations associated with GF-1 for those who were in GF-3B/4. For example, unadjusted geometric means for PFOA were 2.59, 3.02, 3.01, and 2.22 ng/mL for GF-1, GF-2, GF-3A, and GF-3B/4 respectively. Adjusted geometric means for PFOA were 2.34, 2.83, 2.83, and 1.81 ng/mL for GF-1, GF-2, GF-3A, and GF-3B/4 respectively. Thus, PFAS were found to follow inverted U-shaped distributions across different stages of glomerular function. For females, decreases in adjusted PFAS serum levels were initiated at GF-3A, while decreases for males began as early as GF-2. Usually, females are known to have lower levels of PFAS but when in GF-3A and GF-3B/4, females were found to have higher levels of PFAS than males. Thus, inverted U-shaped curves for males and females intersected between GF-2 and GF-3A for PFOA and PFHxS and at GF-3A for PFOS and PFNA. Associations between PFAS and biomarkers of kidney function may be modified in both magnitude and even in direction as kidney function deteriorates. These findings have implications for studies that evaluate associations between PFAS and disease states that affect kidney function, as well as outcome biomarkers known to be affected by kidney function.