Background: The objective of this study was to evaluate the associations of blood lead and cadmium levels with estimated glomerular filtration rate (eGFR) and proteinuria in Korean adults.
Methods: This was a cross-sectional study based on the Korea Nation Health and Nutrition Examination Survey (KNHANES) to analyze the association of blood lead and cadmium levels with renal dysfunction and urine protein excretion. We defined renal dysfunction as eGFR < 60 ml/min/1.73 m(2), as measured by the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation and proteinuria as positive urine dip-stick result.
Results: Blood lead and cadmium levels were significantly increased in the renal dysfunction group compared with the normal renal function group. Lead levels were significantly higher in the proteinuria group than in the group with no proteinuria. There were no differences in cadmium levels according to the amount of proteinuria. Multivariate logistic regression analysis adjusted for age and sex demonstrated higher lead and cadmium levels in the renal dysfunction group than in the group with normal renal function [odds ratio (OR) 1.344, 95 % confidence interval (CI) 1.157-1.162, P < 0.05; OR 1.467, 95 % CI 1.077-1.999, P < 0.05, respectively]. For proteinuria, the fully adjusted ORs comparing the highest versus the lowest lead and cadmium quartiles were 1.22 (95 % CI 1.00-1.50) and 0.51 (95 % CI 0.24-1.08), respectively, showing no significance. For reduced eGFR, the fully adjusted ORs comparing the highest versus the lowest lead and cadmium quartiles were 1.23 (95 % CI 0.98-1.53) and 1.93 (95 % CI 1.39-2.67), respectively, showing the significant association between lead and cadmium levels and renal function. The risk of having reduced eGFR for individuals in the highest quartiles of both lead and cadmium levels in blood was greater than for those in the highest quartile of blood level of lead or cadmium only.
Conclusion: The CKD-EPI equation showed that blood lead and cadmium levels were associated with renal dysfunction in the Korean adult population. This finding has significant implications for environmental institutional strategies regarding heavy metal exposure.