Association between perchlorate, nitrate, and thiocyanate exposure and kidney stones prevalence in US adults: an analysis based on the national health and nutrition examination survey 2007–2018

This study investigates the association between exposure to environmental pollutants-perchlorate, nitrate, and thiocyanate (PNT)-and the prevalence of kidney stone disease (KSD) in US adults, utilizing data from the National Health and Nutrition Examination Survey (NHANES) 2007-2018. With the increasing incidence of KSD, understanding environmental risk factors has become crucial. While PNT compounds are known to be associated with various health issues, their role in KSD remains unclear. A cross-sectional analysis of 11,350 participants measured urinary PNT levels using ion chromatography and electrospray tandem mass spectrometry, adjusting for demographic, lifestyle, and health variables. The analysis found no significant association between urinary perchlorate levels and KSD. However, participants in the highest quartile of urinary nitrate exhibited a significantly higher risk of KSD (OR 1.66, 95% CI [1.27, 2.05]) compared to those in the lowest quartile. Similarly, individuals in the second and third quartiles of urinary thiocyanate also had an elevated risk of KSD (OR 1.39, 95% CI [1.05, 1.85] and OR 1.47, 95% CI [1.08, 2.00], respectively). Restricted cubic spline analysis further demonstrated a nonlinear relationship between both urinary nitrate and thiocyanate levels and KSD risk. While the study benefits from a large, representative sample, its cross-sectional design limits the ability to establish causality, and single urine measurements may not fully capture long-term exposure. Future research should target diverse populations, employ prospective cohort studies, and conduct toxicological experiments to validate these findings and explore the underlying biological mechanisms. The study suggests a complex, non-linear relationship between elevated urinary nitrate and thiocyanate levels and an increased risk of KSD.