Prevalence of blood lead levels ≥5 μg/dL among US children 1 to 5 years of age and socioeconomic and demographic factors associated with blood of lead levels 5 to 10 μg/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) greater than or equal to 5 mug/dL rather than the current 10 mug/dL, we analyzed the most recent available, nationally representative data to identify prevalence of BLLs greater than or equal to 5 mug/dL and socioeconomic and demographic characteristics of 1- to 5-year-old children with BLLs > 5 but < 10 mu 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 >= 5 mu 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 greater than or equal to 5 but < 10 mu g/ dL; >= 10 but < 20 mug/ dL; and greater than or equal to 20 mug/dL) using the group reported as 0.7 to < 5 mu g/dL as the referent. Results. Overall prevalence of BLLs >= 5 mu g/dL among 1- to 5-year-old children was 25.6%, although most ( 76%) of these children had BLLs < 10 mug/ dL. Children with BLLs greater than or equal to 5 mug/ 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 > 5 greater than or equal to mug/ dL. Compared with non- Hispanic white children, non- Hispanic black children were 3 times more likely to have a BLL greater than or equal to 5 but < 10 mu g/dL, 7 times more likely to have a BLL of 10 - 20 mu g/dL, and 13.5 times more likely to have a BLL >= 20 mu 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 >= 5 mu 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 >= 5 mu g/dL are below the current intervention level of 10 mu g/dL. Exposure to lead from multiple sources is suggested by the prevalence of BLLs >= 5 mu g/ dL but < 10 mug/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.