RENAL-FUNCTION IMPAIRMENT IN SECONDARY LEAD SMELTER WORKERS - CORRELATIONS WITH ZINC PROTOPORPHYRIN AND BLOOD LEAD LEVELS

Abstract

Potential kidney function decrement with long-term Pb exposure is important in the overall assessment of adverse health effects of Pb in industrial workers or other exposed groups. Two clinical field studies of secondary Pb smelter workers have shown that a significant proportion of workers had slightly to moderately elevated BUN [blood urea nitrogen] and creatinine levels; the prevalence was higher in those with longer Pb exposure. Since a decrement of kidney function with age was documented, and since duration of Pb exposure may also be strongly related to age, it was necessary to assess the age dependent renal function decrement in a control (non-Pb-exposed) population. BUN and creatinine levels in the Pb-exposed workers showed a much more significant correlation with age than that which was found in the non-exposed population; the correlations between the indicators of renal function, BUN and creatinine, and duration of Pb exposure remained statistically significant after removing the age-dependent decrement derived from the control population. A highly significant correlation between BUN and Zn protoporphyrin levels was found. The results indicate a sizeable and significant decrement in kidney function in the secondary Pb smelter workers studied; this effect was Pb-induced by removing its age-dependency.