Body Burdens of Lead in Hypertensive Nephropathy

Abstract

Chronic lead exposure resulting in blood lead concentrations that exceed 1.93 μmol/l (40 μg/dl) or chelatable urinary lead excretion > 3.14 μmol (650 μg) per 72 h has been associated with renal disease. A previous study had found greater chelatable urine lead excretion in subjects with hypertension and renal failure than in controls with renal failure due to other causes, although mean blood lead concentrations averaged 0.92 μmol/l (19 μg/dl). To determine if chelatable urinary lead, blood lead, or the hematologic effect of lead (zinc protoporphyrin) were greater in hypertensive nephropathy (when hypertension precedes elevation of serum creatinine) than in other forms of mild renal failure, we compared 40 study subjects with hypertensive nephropathy to 24 controls having a similar degree of renal dysfunction due to causes other than hypertension. Lead burdens were similar in both the study and control groups as assessed by 72-h chelatable urinary lead excretion after intramuscular injection of calcium disodium EDTA (0.74 ± 0.63 vs. 0.61 ± 0.40 μmol per 72 h, respectively), and by blood lead (0.35 ± 0.23 vs. 0.35 ± 0.20 μmol/l). We conclude that subjects from a general population with hypertensive nephropathy do not have greater body burdens of lead than renal failure controls.