Concentrations of bisphenol A and its associations with urinary albumin creatinine ratios across the various stages of renal function.

Data from National Health and Nutrition Examination Survey for 2003-2016 for US adults aged ≥ 20 years (N = 10,942) were used to study variabilities and associations with urinary albumin creatinine ratio (UACR) in the adjusted concentrations (AGM) of urine bisphenol A (BPA) across various stages of renal function (RF). RF stages considered were RF-1 (eGFR > 90 mL/min/1.73 m), RF-2 (60 ≤ eGFR ≤ 90 mL/min/1.73 m), RF-3A (45 ≤ eGFR < 60 mL/min/1.73 m), and RF-3B/4 (15 ≤ eGFR < 45 mL/min/1.73 m). Irrespective of gender, race/ethnicity, and smoking status, AGMs for BPA were located on U-curves with point of inflection at RF-2. In general, decreases from RF-1 to RF-2 were followed by increases from RF-2 to RF-3A and from RF-3A to RF-3B/4. For example, AGMs for males were observed to be 1.52, 1.48, 1.61, and 1.69 ng/mL at RF-1, RF-2, RF-3A, and RF-3B/4 respectively. A similar U-curve was observed for those without albuminuria but for those with albuminuria, BPA levels continued increasing until RF-3A before decreasing at RF-3B/4. Severe kidney dysfunction was found to be associated with statistically significantly higher concentrations of BPA in urine. Shape of concentration curves for BPA across RF stages is determined by the balance of actively mediated secretion and reabsorption operating on both sides of renal proximal tubules during each stage of RF. Shape of concentration curves for BPA across various stages of RF was age and concentration dependent. Associations between BPA and UACR were found to be negative (p = 0.02), positive (p = 0.23), negative (p = 0.53), and negative (p < 0.01) respectively at RF-1, RF-2, RF-3A, and RF-3B/4 respectively.