Surveillance for elevated blood lead levels among children--United States, 1997-2001.MMWR Surveill Summ. 2003 Sep 12; 52(10):1-21.MS
Lead is neurotoxic and particularly harmful to the developing nervous systems of fetuses and young children. Extremely high blood lead levels (BLLs) (i.e.,> or =70 microg/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's learning and behavior. In 1990, the U.S. Department of Health and Human Services established a national goal to eliminate BLLs >25 microg/dL by 2000; a new goal targets elimination of BLLs > or =10 microg/dL in children aged <6 years by 2010.
Information regarding children's BLLs comes from 1) National Health and Nutrition Examination Surveys (NHANES) conducted during 1976-1980, 1988-1991, 1991-1994, and 1999-2000; and 2) state child blood lead 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 local surveillance data. NHANES reports data regarding children aged 1-5 years; state and local surveillance systems report data 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 regarding the health and nutritional status of the civilian, noninstitutionalized U.S. population. State and local childhood lead surveillance systems are based on reports of blood lead tests from laboratories. State and local programs submit data to CDC annually. In this report, confirmed elevated BLLs are defined as one venous blood specimen > or =10 microg/dL or two capillary blood specimens > or =10 microg/dL drawn within 12 weeks of each other.
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 > or =10 microg/dL. For 2001, a total of 44 states, the District of Columbia (DC), and New York City (NYC) submitted child blood lead surveillance data to CDC. These jurisdictions represent 95% of the U.S. population of children aged <72 months and 97% of the nation's pre-1950 housing. The number of children tested and reported to CDC increased from 1,703,356 in 1997 (37 states, DC, and NYC reporting), to 2,422,298 in 2001 (44 states, DC, and NYC reporting). During that time, the number of children reported with confirmed elevated BLLs > or =10 microg/dL steadily decreased from 130,512 in 1997 to 74,887 in 2001. In 2000, the year targeted for national elimination of BLLs >25 microg/dL, a total of 8,723 children had BLLs > or =25 microg/dL.
Both national surveys and state surveillance data indicate children's BLLs continue to decline throughout the United States. However, thousands of children continue to be identified with elevated BLLs. The 2000 goal of eliminating BLLs >25 microg/dL was not met. Attaining the 2010 goal of eliminating BLLs > or =10 microg/dL will require intensified efforts to target areas at highest risk, evaluate preventive measures, and improve the quality of surveillance data.
PUBLIC HEALTH ACTIONS
States will continue to use surveillance data to 1) promote legislation supporting lead poisoning prevention activities, 2) obtain funding, 3) identify risk groups, 4) target and evaluate prevention activities, and 5) monitor and describe progress toward elimination of BLLs > or =10 microg/dL. CDC will work with state and local programs to improve tracking systems and the collection, timeliness, and quality of surveillance data.