Lead poisoning: An update

1. Based on level A epidemiologic data, the epidemiology of the gold standard for assessing lead (Pb) exposure and absorption in young children, blood Pb levels (BLLs), shows a public health success story during the past 50 years. 2. However, during the same period, our knowledge about Pb toxicity has pushed the BLL of concern lower and lower. We still do not have a safe BLL below which we cannot demonstrate toxicity. Based on level A observational studies, some Pb effects on the brain are permanent. 3. Based on level A epidemiologic evidence, in lieu of a BLL toxicity threshold, the CDC has chosen to direct intervention efforts at children with the highest levels, which in a 2010 nationally representative cohort was at least 5 lg/dL ($0.24 mmol/L). 4. Based on level B evidence, Pb interventions have not changed substantially in recent decades: identifying and eliminating sources of exposure, usually Pb-based paint; reducing nonnutritive hand- or object-to-mouth activity; preventing Pb-containing dust ingestion; eliminating nutritional deficiency states for essential elements, especially calcium and iron; and, for a small subgroup of children with BLLs of 45 lg/dL or greater ($2.17 mmol/L), chelation therapy. 5. Although the magnitude of Pb poisoning in the United States has been reduced, new sources of exposure are continually being discovered, as well as old sources in new locations, such as water fountains and walls in schools. Based on level A evidence from epidemiologic data, because enormous amounts of Pb have been disseminated throughout the United States, millions of children likely will continue to become Pb poisoned in the coming decades. Based on level A evidence from epidemiologic studies, in other countries, Pb poisoning still has lethal outcomes. 6. Based on level D evidence, the primary care provider is in the prime position to prevent the possibility of Pb poisoning from becoming a reality through assessments of patients, education of caregivers, and advocacy to eliminate exposure.