Introduction: We studied the relationship between renal dysfunction and occupational lead exposure in a local factory.Materials and Methods: A cross-sectional study with a cohort component was conducted with 55 male workers of a factory producing PVC stabilisers as subjects. Workers from this factory have been followed up with 6-monthly blood lead measurements since 1982. Two indices of overall lead exposure, i.e. the number of times a worker’s blood lead exceeded 40 µg/dL (PbB40) and cumulative blood lead index (PbBint), were obtained from this data. Recent blood lead concentration (PbB) was measured. 4-hour creatinine clearance and various other urinary and serum markers of renal dysfunction were used as effect indices. Results: There was no relationship between PbB and any of the renal markers. However, creatinine clearance decreased significantly (P <0.001) with increasing PbB40 and PbBint after adjustment for age and smoking habits. Urinary albumin (Ualb), urinary α-1 microglobulin (Uα1m), urinary β-2 microglobulin (Uβ2m) and urinary retinol-binding protein (URBP) increased significantly with both increasing PbB40 and PbBint. Total urinary activity of N-acetyl-β-D-glucosaminidase (NAG-T) and its heat-stable isoenzyme (NAG-B) increased significantly with increasing PbB40. A significant difference in renal parameters occurred when PbB40 was 1 or more. Conclusions: We have found a positive association between overall lead exposure and renal dysfunction. The renal parameters were significantly higher among those who had at least one episode of blood lead above 40 µg/dL. Our findings also strengthen the case for the use of Ualb, Uα1m, Uβ2m, URBP, NAG-T and NAG-B as early markers of lead nephropathy.
Chronic lead exposure causes progressive nephropathy that eventually results in renal failure. Known as chronic lead nephropathy, this disease has been recognised since the 19th century and is occasionally accompanied by hypertension and gout.
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