Dose-response evaluation of urinary cadmium and kidney injury biomarkers in Chinese residents and dietary limit standards

BackgroundCadmium (Cd) is a common heavy metal that mainly causes renal damage. There is a lack of research on the large-scale and systematic evaluation of the association between urinary Cd (U-Cd) and various effect biomarkers among Chinese residents.MethodsBased on the establishment process of dietary Cd limit standards by European Food Safety Authority (EFSA), the dose-response relationships between U-Cd and four biomarkers, beta (2)-microglobulin (beta (2)-MG), N-acetyl-beta -glucosidase (NAG), microalbumin (mALB), and retinol binding Protein (RBP) were explored, respectively. Toxicokinetic model was used to derive the dietary Cd exposure limit for Chinese residents after critical U-Cd concentration was calculated.ResultsAs the sensitive biomarkers of renal injury, beta (2)-MG and NAG were selected to estimate the 95% confidence interval lower limit of the U-Cd benchmark dose (BMDL5) to be 3.07 and 2.98 mu g/g Cr, respectively. Dietary Cd exposure limit was calculated to be 0.28 mu g/kg bw/day (16.8 mu g/day, based on the body weight of 60 kg), which was lower than the average Chinese Cd exposure (30.6 mu g/day) by the China National Nutrient and Health Survey.ConclusionThis study established an overall association between U-Cd and renal injury biomarkers, and explored the Chinese dietary Cd exposure limits, which helps improve Chinese Cd exposure risk assessment and provides a reference basis for formulating reasonable exposure standards.

Automated summary

This study established the relationship between U-Cd and renal injury biomarkers, and calculated the dietary Cd exposure limit for Chinese residents based on toxicokinetic model. The findings contribute to improving Chinese Cd exposure risk assessment and setting reasonable exposure standards.