A review of lead exposure source attributional studies

Despite the global phase-out of leaded gasoline, lead poisoning is estimated to cause 5.5 million premature deaths and the loss of 765 million IQ points annually. However, the contributions of different lead exposure sources to blood lead levels (BLLs) are poorly understood. We conducted a systematic literature review using the Scopus database, examining 39 studies that attribute BLLs to specific sources of lead exposure, published since the year 2000 and with sample sizes >100. The 39 studies were from 26 countries; 22 were from low- and middle-income countries, with an average sample size of 1003 participants. Twenty-three of the studies reported absolute BLL impacts (μg/L) from lead exposure sources, other studies reported odds ratios for elevated BLLs (>50 or > 100 μg/L). Averaged across the studies, the BLL impacts were 42.3 μg/L from living near industrial lead pollution hotspots, 31.4 μg/L from occupational and take-home exposure, 28.0 μg/L from deteriorated paint, 19.8 μg/L from traditional medicines and cosmetics, 19.3 μg/L from foodware (glazed ceramics and melamine plates), 17.3 μg/L from smoking, 15.4 μg/L from foods, and 12.9 μg/L from geophagy. Only one of the reviewed studies assessed the BLL impact of metal cookware, and did not find a significant relationship with BLLs. However, the statistical power of the attributional studies to detect relationships with BLLs was often limited. Future studies should investigate the ingestion routes from industrial pollution, the contamination of foods and spices, BLL impacts of lead-contaminated metal cookware, and traditional medicines administered to young children and infants.