Changing trends in the epidemiology of pediatric lead exposure: Interrelationship of blood lead and ZPP concentrations and a comparison to the US population

Objectives: To determine blood lead and zinc protoporphyrin (ZPP) concentrations in a pediatric population, confirm their interrelationship at low blood lead concentrations, and assess changing trends through comparison of these data with those found in a similar population 10 years earlier and to US national values. Study Design and Methods: The study was conducted in a large pediatric hospital in the Washington DC area (CNMC) on patient whole blood specimens (n = 4908) (0-17 years) accrued from January 2001 to June 2002. Pediatric blood lead concentrations were determined by atomic absorption spectrophotometry, and ZPP by hematofluorometry. The data were analyzed using a computer adaptation of the Hoffmann approach. Results and Conclusions: Blood lead level (BLL) means ranged between 2.2 and 3.3 mug/dL, and the median BLL was 3 mug/dL throughout. Mean ZPP concentrations ranged between 21.1 and 26.6 mug/dL and the median concentrations between 21 and 27 mug/dL. In comparison to data obtained from a similar pediatric population at CNMC between 1991 and 1992, pediatric BLLs have significantly declined in the Washington DC area. The current data are also compared with data obtained from the National Health and Nutrition Examination Survey (NHANES III) of the US population. The interrelationship between ZPP and BLLs is examined.