cdc.govSurveillance for Elevated Blood Lead Levels Among Children --- United States, 1997--2001Surveillance for Elevated Blood Lead LevelsAmong Children --- United States, 1997--2001Pamela A. Meyer, Ph.D.1Timothy Pivetz2Timothy A. Dignam, M.P.H.1David M. Homa, Ph.D.1Jaime Schoonover3Debra Brody, M.P.H.41Division of Emergency and Environmental Health Services, National Center for Environmental Health, CDC2Centers for Public Health Research and Evaluation, Battelle, Columbus, Ohio3Electronic Data Systems, Atlanta, Georgia4Division of Health and Nutrition Examination Surveys, National Center for Health Statistics, CDCAbstractProblem/Condition: Lead is neurotoxic and particularly harmful to the developing nervous systems of fetuses andyoung children. Extremely high blood lead levels (BLLs) (i.e., >70 µg/dL) can cause severe neurologic problems (e.g.,seizure, coma, and death). However, no threshold has been determined regarding lead's harmful effects on children'slearning and behavior. In 1990, the U.S. Department of Health and Human Services established a national goal toeliminate BLLs >25 µg/dL by 2000; a new goal targets elimination of BLLs >10 µg/dL in children aged <6 years by2010.Reporting Period: Information regarding children's BLLs comes from 1) National Health and Nutrition ExaminationSurveys (NHANES) conducted during 1976--1980, 1988--1991, 1991--1994, and 1999--2000; and 2) state child bloodlead surveillance data for test results collected during 1997--2001.Description of System: CDC tracks children's BLLs in the United States by using both NHANES and state and localsurveillance data. NHANES reports data regarding children aged 1--5 years; state and local surveillance systems reportdata regarding children aged <72 months. Because lead exposure in children varies among populations and communities,both surveys are needed to determine the burden of elevated BLLs among young children throughout the United States.NHANES uses highly standardized data-collection procedures and probability samples to gather information regardingthe health and nutritional status of the civilian, noninstitutionalized U.S. population. State and local childhood leadsurveillance systems are based on reports of blood lead tests from laboratories. State and local programs submit data toCDC annually. In this report, confirmed elevated BLLs are defined as one venous blood specimen >10 µg/dL or twocapillary blood specimens >10 µg/dL drawn within 12 weeks of each other.Results: The NHANES 1999--2000 survey estimated that 434,000 children (95% confidence interval =189,000--846,000) or 2.2% of children aged 1--5 years had BLLs >10 µg/dL. For 2001, a total of 44 states, the District ofColumbia (DC), and New York City (NYC) submitted child blood lead surveillance data to CDC. These jurisdictionsrepresent 95% of the U.S. population of children aged <72 months and 97% of the nation's pre-1950 housing. Thenumber of children tested and reported to CDC increased from 1,703,356 in 1997 (37 states, DC, and NYC reporting), to2,422,298 in 2001 (44 states, DC, and NYC reporting). During that time, the number of children reported with confirmedelevated BLLs >10 µg/dL steadily decreased from 130,512 in 1997 to 74,887 in 2001. In 2000, the year targeted fornational elimination of BLLs >25 µg/dL, a total of 8,723 children had BLLs >25 µg/dL.Surveillance for Elevated Blood Lead Levels Among Children --- United States, 1997--2001http://www.cdc.gov/mmwr/preview/mmwrhtml/ss5210a1.htm (1 of 23) [8/16/2004 11:58:02 AM]Interpretation: Both national surveys and state surveillance data indicate children's BLLs continue to declinethroughout the United States. However, thousands of children continue to be identified with elevated BLLs. The 2000goal of eliminating BLLs >25 µg/dL was not met. Attaining the 2010 goal of eliminating BLLs >10 µg/dL will requireintensified efforts to target areas at highest risk, evaluate preventive measures, and improve the quality of surveillancedata.Public Health Actions: States will continue to use surveillance data to 1) promote legislation supporting lead poisoningprevention activities, 2) obtain funding, 3) identify risk groups, 4) target and evaluate prevention activities, and 5)monitor and describe progress toward elimination of BLLs >10 µg/dL. CDC will work with state and local programs toimprove tracking systems and the collection, timeliness, and quality of surveillance data.IntroductionExposure to lead can damage the nervous, hematopoietic, and renal systems (1,2) and is particularly harmful to thedeveloping nervous systems of fetuses and children aged <72 months. Extremely elevated blood lead levels (BLLs) >70µg/dL can cause severe neurologic problems (e.g., seizure, coma, and death) (3). Although severe cases are rare today(4), the threshold for harmful effects of lead remains unknown. Since 1975, as new data became available, CDC hasrevised its recommendations regarding the threshold of BLLs that should raise concern and trigger interventions (5--7).By 1991, CDC had lowered the BLL threshold 66.6% to 10 µg/dL, from 30 µg/dL in 1975 (5,7), in response to studies inthe late 1980s that linked BLLs as low as 10 µg/dL with decreased intelligence and other adverse neurodevelopmentaleffects (8--11). Ongoing research conducted since 1991 provides evidence of adverse effects at even lower levels, <10µg/dL, among children aged <72 months (12--16).The principal sources of lead exposure for children in the United States are house dust contaminated by leaded paint andsoil contaminated by both leaded paint and decades of industrial and motor vehicle emissions (1). Lead was widely usedin paint through the 1940s. Although lead use declined during the 1950s and 1960s (17), and lead was banned fromresidential use in 1978*, lead remains a hazard in homes built before the ban, especially in pre-1950 housing. During1991--1994, CDC's National Health and Nutrition Examination Survey (NHANES) determined the prevalence of BLLs>10 µg/dL was highest among children living in pre-1946 homes (8.6%), compared with children living in homes builtduring 1946--1973 (4.6%), and after 1973 (1.6%). Among children living in pre-1946 housing, prevalence of BLLs >10µg/dL differed substantially by family income. Prevalence among children from low-income families was 16.4%,compared with 4.1% and 0.9% among children from middle- and high-income families (18).National Elimination GoalsThe U.S. Department of Health