Low-level environmental exposure to lead and progressive chronic kidney diseases.

PURPOSE To determine whether low-normal body lead burden (BLB) accelerates progressive renal insufficiency in nondiabetic patients with chronic kidney diseases (CKD). METHODS One hundred eight CKD patients (serum creatinine between 1.5 and 2.9 mg/dL) with low-normal BLB (<80 microg) and no lead exposure history were observed for 24 months. Following the observation, 32 patients with low-normal BLB (> or =20 microg and <80 microg) were randomly assigned to chelation and control groups. The chelation group patients were given edetate calcium disodium (EDTA) chelation therapy for 3 months and repeated chelation therapy during the following 24 months to maintain their BLB below 20 mug, while the control group patients underwent placebo therapy. The primary endpoint was an increased serum creatinine level to 1.25 times the baseline value. The secondary endpoint was temporal changes in renal function. RESULTS The primary endpoint occurred in 14 patients in the observation period. Baseline BLB was the important risk factor in determining progressive renal insufficiency. The mean glomerular filtration rate (GFR) change in the chelation group patients was 6.6+/-10.7 mL/min/1.73m(2), compared with -4.6+/-4.3 mL/min/1.73 m2 in control group patients (P <.001) at the end of the intervention period. The mean decrease in GFR per year of chelation group patients was lower than that of control group patients during the repeated chelation period. CONCLUSION Environmental exposure to lead, even at low level, may accelerate progressive renal insufficiency of nondiabetic patients with CKD.