Effects of Exposure to Low Levels of Environmental Cadmium on Renal Biomarkers Curtis W. Noonan,1 Sara M. Sarasua,1 Dave Campagna,1 Steven J. Kathman,1 Jeffrey A. Lybarger,1 and Patricia W. Mueller2 1Agency for Toxic Substances and Disease Registry, Division of Health Studies, Health Investigations Branch, Atlanta, Georgia, USA; 2Centers for Disease Control and Prevention, National Center for Environmental Health, Atlanta, Georgia, USA Abstract We conducted a study among residents of a small community contaminated with heavy metals from a defunct zinc smelter and residents from a comparison community to determine whether biologic measures of cadmium exposure were associated with biomarkers of early kidney damage. Creatinine-adjusted urinary cadmium levels did not differ between the smelter and comparison communities ; thus we combined individuals from both communities (n = 361) for further analyses. The overall mean urinary cadmium level was low, 0.26 µg/g creatinine, similar to reference values observed in the U.S. general population. For children ages 6-17 years, urinary concentration of N-acetyl-ß-d-glucosaminidase (NAG) , alanine aminopeptidase (AAP) , and albumin were positively associated with urinary cadmium, but these associations did not remain statistically significant after adjusting for urinary creatinine and other potential confounders. For adults ages 18 or older, urinary concentration of NAG, AAP, and albumin were positively associated with urinary cadmium. The associations with NAG and AAP but not with albumin remained statistically significant after adjusting for creatinine and other potential confounders. We found a positive dose-effect relationship between levels of creatinine-adjusted urinary cadmium and NAG and AAP activity, and statistically significant differences in mean activity for these two enzymes between the highest ( 1.0 µg cadmium/g creatinine) and the lowest (< 0.25 µg cadmium/g creatinine) exposure groups. The findings of this study indicate that biologic measures of cadmium exposure at levels below 2.0 µg/g creatinine may produce measurable changes in kidney biomarkers. Key words: alanine aminopeptidase, albumin, ß2-microglobulin, cadmium, kidney, N-acetyl-ß-d-glucosaminidase. Environ Health Perspect 110:151-155 (2002) . [Online 16 January 2002] http://ehpnet1.niehs.nih.gov/docs/2002/110p151-155noonan/ abstract.html Address correspondence to C.W. Noonan, Agency for Toxic Substances and Disease Registry, 1600 Clifton Road NE, Mail stop E-31, Atlanta, GA 30333 USA. Telephone: (404) 498-0588. Fax: (404) 498-0079. E-mail: cnoonan@cdc.gov We thank J. Logue and J. Fox of the Pennsylvania Department of Health for their work on the study ; D. Pascal, National Center for Environmental Health (NCEH) , who performed the cadmium assays ; C. Dodson, NCEH, who coordinated specimen collection ; R. Amler, M. McGeehin, G. Mastry, and F. Stallings for technical guidance ; and M. White, Agency for Toxic Substances and Disease Registry, for extensive editorial and technical guidance. Received 19 March 2001 ; accepted 24 July 2001. The full version of this article is available for free in HTML or PDF formats. |