Association between urinary arsenic levels and kidney damage in US adults: NHANES 2007-2018

Background: Chronic arsenic exposure is known to be associated with various diseases by inducing multiple organ dysfunctions. Despite the high prevalence of kidney diseases in the US and globally, population-level research on the link between inorganic arsenic and kidney damage remains limited. In our study, we assessed the association between urinary arsenic levels and kidney damage among US adults using a multi-marker approach. Methods: We analyzed data from the National Health and Nutrition Examination Survey (2007-2018). Multivariable logistic regression models were employed to estimate the odds ratios (ORs) for kidney damage based on total urinary arsenic levels and multiple kidney biomarkers, including albuminuria, low estimated glomerular filtration rate (eGFR), hyperuricemia, and elevated blood urea nitrogen (BUN), while adjusting for demographic, socioeconomic, and other risk factors. Total urinary arsenic levels were calculated by summing the levels of arsenous acid (As3), arsenic acid (As5), and their methylated metabolites, monomethylarsinic acid (MMA), and dimethylarsinic acid (DMA). Dimethylarsinic acid (DMA) was calibrated for arsenobetaine using a residual regression method to minimize the influence of seafood-related exposure. Results: After adjusting for covariates, we observed 1.29-fold higher odds (95 % CI 1.01, 1.64) of kidney damage in the highest quartile of urinary arsenic compared to the lowest quartile. Specifically, the odds of albuminuria and hyperuricemia were 1.49-fold (95 % CI 1.09, 2.03) and 1.38-fold (95 % CI 1.01, 1.88) higher, respectively, in the highest quartile. Additionally, for every one-unit increase in the natural log of arsenic levels, significant associations were observed for overall kidney damage (OR 1.10, 95 % CI 1.01, 1.20), albuminuria (OR 1.15, 95 % CI 1.03, 1.29), and hyperuricemia (OR 1.12, 95 % CI 1.02, 1.24) when considering arsenic levels in drinking water as a continuous variable. Conclusion: Our study concludes that higher urinary arsenic levels are positively associated with kidney damage. Further prospective studies are needed to confirm these findings.