Prevalence of blood lead levels >or= 5 micro g/dL among US children 1 to 5 years of age and socioeconomic and demographic factors associated with blood of lead levels 5 to 10 micro g/dL, Third National Health and Nutrition Examination Survey, 1988-1994.

OBJECTIVES: As part of an investigation into the impact of a potential revision in federal childhood lead poisoning prevention policy that would result in screening children for blood lead levels (BLLs) >or=5 micro g/dL rather than the current 10 micro g/dL, we analyzed the most recent available, nationally representative data to identify prevalence of BLLs >or=5 micro g/dL and socioeconomic and demographic characteristics of 1- to 5-year-old children with BLLs >or=5 but <10 micro g/dL.
METHODS: We performed statistical analyses on data from the Third National Health and Nutrition Examination Survey (NHANES III) (1988-1994) to describe trends in BLLs >or=5 micro g/dL overall and among subpopulations of children <6 years old and to compare risk factors for falling within 1 of 3 groups of children (those with BLLs >or=5 but <10 micro g/dL; >or=10 but <20 micro g/dL; and >or=20 micro g/dL) using the group reported as 0.7 to <5 micro g/dL as the referent.
RESULTS: Overall prevalence of BLLs >or=5 micro g/dL among 1- to 5-year-old children was 25.6%, although most (76%) of these children had BLLs <10 micro g/dL. Children with BLLs >or=5 micro g/dL included 46.8% of non-Hispanic black children, 27.9% of Mexican American children, and 18.7% of non-Hispanic white children; 42.5% of children in housing built before 1946, 38.9% of children in housing built between 1946 and 1973, and 14.1% of children in housing built after 1973 had BLLs >or=5 micro g/dL. Compared with non-Hispanic white children, non-Hispanic black children were 3 times more likely to have a BLL >or=5 but <10 micro g/dL, 7 times more likely to have a BLL of 10-20 micro g/dL, and 13.5 times more likely to have a BLL >or=20 micro g/dL. Similar increases in the association between risk factor and BLL were seen with respect to other known risk factors including age of housing, region of the country, and poverty.
CONCLUSIONS: The high prevalence of BLLs >or=5 micro g/dL overall and within US subpopulations will be an important variable in any change in screening and intervention criteria. However, most children with BLLs >or=5 micro g/dL are below the current intervention level of 10 micro g/dL. Exposure to lead from multiple sources is suggested by the prevalence of BLLs >or=5 micro g/dL but <10 micro g/dL among children with uncertain risk factors. The probable presence of one or more known risk factors for childhood lead poisoning increases as BLL increases.