Organic Pollutant Exposure and CKD: A CRIC (Chronic Renal Insufficiency Cohort) Pilot Study

Rationale and ObjectiveThis study aimed to assess the impact of exposure to organic pollutants in adults with chronic kidney disease (CKD).Study designCross-sectional and longitudinal analysisSetting and Participants40 adults enrolled in the Chronic Renal Insufficiency Cohort (CRIC).ExposuresExposure at baseline and longitudinally to various organic chemical pollutantsOutcomes(1) Death; (2) Composite of congestive heart failure, myocardial infarction, and stroke, (3) Event-free survival from kidney failure, or ≥50% decline in eGFR; and (4) Longitudinal trajectory of eGFR.Analytical ApproachWe used HPLC-MS/MS to measure urinary concentrations of bisphenols, phthalates, organophosphate pesticides, polycyclic aromatic hydrocarbons, melamine, and cyanuric acid at years 1, 3 and 5 after enrollment in CRIC. Univariate and multivariable logistic regression were used to examine association of individual compounds and classes of pollutants on the outcomes. The Cox proportional hazards model and Kaplan-Meier method were used to calculate hazard ratios and 95% confidence intervals for each class of pollutants.ResultsMedian baseline eGFR and urinary protein:creatinine ratio were 33 ml/min/1.73 m2 and 0.58 mg/g, respectively. Of 52 compounds assayed, 30 were detectable in ≥50% of participants. Urinary chemical concentrations were comparable in CKD patients to healthy individuals from contemporaneous National Health and Nutrition Examination Survey cohorts. Phthalates were the only class with a trend towards higher exposure in CKD patients. There was an inverse relationship between exposure and eGFR slope for bisphenol F, mono-(3-carboxypropyl) phthalate, mono-benzyl phthalate, mono-[2-(carboxymethyl)hexyl] phthalate, and melamine. There were no associations between organic pollutant exposure and CV outcomes.LimitationsSmall sample size, evaluation of single rather than combined exposuresConclusionsSimultaneous measurement of multiple organic pollutants in adults with CKD is feasible. Exposure levels are comparable to healthy individuals. Select contaminants, especially in the phthalate class, may be associated with more rapid deterioration in kidney function.Plain Language SummaryThe impact of exposure to organic pollutants has not been studied in adults with chronic kidney disease. (CKD). To fill this gap, we measured the exposure to a wide range of chemicals that are found in plastics, personal care products, and food preparation. Overall, the exposure was similar to healthy population living in the United States. Only select compounds, mainly phthalates, demonstrated a trend with a more rapid decline in kidney function. These findings provide a useful reference for future studies that aim to evaluate organic pollutant exposure in patients with CKD. This is significant because these exposures represent a modifiable risk factor for disease progression by alterations in diet or lifestyle.