SERUM URIC ACID AND STANDARDIZED URINARY PROTEIN: RELIABLE BIOINDICATORS OF LEAD NEPHROPATHY IN NIGERIAN LEAD WORKERS

The question as to whether lead causes renal damage still remains largely controversial. Eighty-five male lead workers and 51 control subjects who had never been occupationally exposed to lead were studied. They were also classified according to duration of exposure. The mean age of the lead workers was similar to that of control subjects. The mean duration of occupational exposure to lead was 16.7 ± 2.13 years. Blood lead level was significantly higher in Pb workers than in controls (P < 0.001). Serum creatinine level did not differ significantly between lead workers and controls. Urinary microalbumin level was elevated in lead workers compared with controls but this was not significant (P>0. 05). Serum uric acid level was significantly raised in lead workers than in controls (P<0. 001). In addition it was significantly correlated with blood lead level (r = 0.24, P < 0.0026). Standardized total urinary protein was also significantly raised in lead workers compared with control (P < 0. 001). Serum potassium level was equally significantly higher in lead workers than in controls (P < 0.01). In contrast serum total calcium level was significantly decreased in lead workers than in controls (P < 0.01), while serum phosphate level did not differ significantly. Serum uric acid level and standardized urinary protein determination may prove a readily available, reliable marker of lead nephropathy in Nigerians.