Occupational and environmental lead exposure in Port Harcourt, Nigeria: analysis of its association with renal function indices

ABSTRACT

Background: In spite of the high risk of lead exposure in Nigeria, there is a paucity of data on the occupational and environmental burden of lead exposure and its impact on human health especially its nephrotoxic effects. This study aims to assess the degree of occupational and environmental lead exposure in Port Harcourt Nigeria and the relationship between lead exposure and indices of renal function. Methods: A cross sectional comparative study of 190 adult subjects with occupational lead exposure and 80 matched controls. Blood lead was used as the biomarker of lead exposure. Serum urea, creatinine, uric acid, urine albumin and glomerular filtration rate were the renal function indices measured. Results: Occupationally lead exposed subjects had higher mean blood lead 50.37±24.58 ug/dl, than controls 41.40±26.85 ug/dl (p= 0.008). The mean values of serum urea, creatinine and uric acid were significantly higher in study subjects compared to controls 3.06±0.81 mmol/L vs. 2.7±0.84 mmol/L (p = 0.002), 87.2±14.30 umol/L vs. 80.68±14.70 umol/L (p = 0.001) and 271.93±71.18 umol/L vs. 231.1±62.70 umol/L (p = 0.000) respectively. Creatinine clearance was significantly lower in subjects compared to controls 98.86±21.26 ml/min/1.72m2 vs.108.18±25.16 ml/mi /1.72m2 (p = 0.002). Blood lead correlated positively only with blood urea [r = .031, r2 = .017, p = .031] and negatively [r = -.144, r2 = .021, p = .018] with serum phosphate. Conclusion: The level of environmental and occupational lead exposure in Port Harcourt, Nigeria is high, with occupational lead exposure increasing the risk of lead toxicity and renal function impairment