High blood lead levels compromise the total antioxidant status of normal healthy adults in a population in Karachi

Objective: To find out the total antioxidant status (TAS) and its relationship to blood lead (Pb) in apparently healthy adults in a population in Karachi. Methodology: In a cross-sectional study, a cohort of 132 healthy adults (67 having blood Pb levels below 7 mu g/dl and 65 having blood Pb levels above 11 mu g/dl) were randomly selected from 872 healthy adults (age 18-60 years) recruited from a low-income population in Karachi. TAS in serum was analyzed using spectrophotometric assay based kit, while blood Pb levels were determined using Atomic Absorption Spectrometric method. Results: Mean serum TAS levels were significantly less in subjects with high blood Pb concentration compared to those with low blood Pb concentration (1.05 +/- 0.27 mmol/l vs 1.16 +/- 0.24 mmol/l; P=0.01). In a correlation analysis adjusted for age and gender, TAS levels were found to be modestly associated with blood Pb [Pearson's r=-0.2; P=0.02]. Conclusion: Mean TAS levels were significantly decreased in apparently healthy adults with high blood Pb in a general population in Karachi. Exposure to Pb pollution could be compromising antioxidant ability of individuals in the study population.