Cadmium is a common environmental contaminant and is associated with nephrotoxic effects, particularly at high exposure levels. There is some indication, however, that changes in sensitive renal biomarkers such as N-acetyl-B-D-glucosaminidase (NAG) may occur among environmentally exposed populations at lower levels than previously estimated. A study was conducted among individuals with relatively low urinary concentrations of cadmium to determine whether low-level cadmium exposure was associated with biomarkers of early kidney damage. Spot urine samples were collected from 154 adults and analyzed for cadmium, albumin, and the tubular brush border enzymes, NAG and alanine aminopeptidase (AAP). The overall mean urinary cadmium level was low, 0.26 mg/g creatinine with a maximum of 2.15 mg/g creatinine. Urinary concentrations of NAG, AAP, and albumin were positively associated with urinary cadmium. The associations with NAG and AAP remained strong after adjusting for creatinine, age, sex, and self-reported diabetes. There was a positive dose-response relationship between levels of creatinine-adjusted urinary cadmium and NAG and AAP levels and statistically significant differences in mean activity for these two enzymes between the highest (> 1.0 mg cadmium/g creatinine) and the lowest (< 0.25 mg cadmium/g creatinine) exposure groups. Follow-up studies of low-exposure populations such as these may help to determine if the observed changes in excreted enzymes are reflective of early, irreversible tubular damage or overly sensitive indications of subclinical effects that will never progress to actual renal dysfunction.
Learning Objectives: At the conclusion of the session, the participant (learner) in this session will be able to:
Presenting author's disclosure statement:
Organization/institution whose products or services will be discussed: Agency for Toxic Substances and Disease Registry
I do not have any significant financial interest/arrangement or affiliation with any organization/institution whose products or services are being discussed in this session.