Blood cadmium and lead and chronic kidney disease in US adults: a joint analysis

Environmental cadmium and lead exposures are widespread, and both metals are nephrotoxic at high exposure levels. Few studies have evaluated the associations between low-level cadmium and clinical renal outcomes, particularly with respect to joint cadmium and lead exposure. The geometric mean levels of blood cadmium and lead were 0.41 microg/L (3.65 nmol/L) and 1.58 microg/dL (0.076 micromol/L), respectively, in 14,778 adults aged >or=20 years who participated in the National Health and Nutrition Examination Survey (1999-2006). After adjustment for survey year, sociodemographic factors, chronic kidney disease risk factors, and blood lead, the odds ratios for albuminuria (>or=30 mg/g creatinine), reduced estimated glomerular filtration rate (eGFR) (<60 mL/minute/1.73 m(2)), and both albuminuria and reduced eGFR were 1.92 (95% confidence interval (CI): 1.53, 2.43), 1.32 (95% CI: 1.04, 1.68), and 2.91 (95% CI: 1.76, 4.81), respectively, comparing the highest with the lowest blood cadmium quartiles. The odds ratios comparing participants in the highest with the lowest quartiles of both cadmium and lead were 2.34 (95% CI: 1.72, 3.18) for albuminuria, 1.98 (95% CI: 1.27, 3.10) for reduced eGFR, and 4.10 (95% CI: 1.58, 10.65) for both outcomes. These findings support consideration of cadmium and lead as chronic kidney disease risk factors in the general population and provide novel evidence of risk with environmental exposure to both metals.