Causes of lead toxicity in a Nigerian city

Background: Up to 70% of young Nigerian children have been reported to have blood lead concentrations ⩾10 μg/dl. Aims: To better elucidate risk factors for lead toxicity among Nigerian families with children at risk for lead toxicity. Methods: Two geographic wards in Jos, Nigeria were selected for study, one previously reported to have a high mean blood lead level (37 (SD 13) μg/dl) and one with a lower mean blood lead level (17 (SD 10) μg/dl) in young children. Data pertaining to potential risk factors for lead exposure were collected from children and adults in 34 households. Results: The mean (SD) blood lead concentration of 275 subjects, aged 3 weeks to 90 years, was 8.7 (5.7) μg/dl (range 1–34 μg/dl); 92 (34%) had concentrations ⩾10 μg/dl. In multivariate analysis, an age of 5 years and under, flaking house paint, residence near a gasoline seller, male gender, increasing maternal and paternal education, and use of a lead ore eye cosmetic were independently associated with greater blood lead concentration. Vehicle ownership was associated with reduced lead concentration. Compared with the low-lead ward, residence in the high-lead ward remained significantly associated with greater lead values, indicating that additional factors likely contribute to lead exposure. Conclusion: Although the cause of increased lead levels in Jos appears to be multi-factorial, several remediable sources contribute to lead exposure in Nigeria.