Factors Contributing to Blood Lead Levels of U.S. Children

Abstract

While elemental lead has been removed from a variety of products over the past 30 years, it is still a widely distributed metal in the environment and can be found in old electronics, children's toys, and ceramics resulting in the exposure of young children. To determine what factors contribute to blood lead levels in children, and therefore, help determine possible exposure routes, we assessed the effect of housing and general demographic factors and determined which characteristics had the greatest influence on lead levels for children. Blood lead levels (BLLs), demographic data, and housing data from the third National Health and Nutrition Examination Survey (NHANES) (1988–1994) and the three continuous NHANES cycles (1999–2000, 2001–2002, 2003–2004) were used in these analyses. Using SAS software, potential correlations between BLLs and various characteristics were determined using simple linear regression while multivariate regression was utilized to assess the significance of several factors while controlling for known predictors of blood lead levels in children 1–5 years of age. Age of housing, being non-Hispanic black, and age of child had the greatest effect on lead levels in children. Non-Hispanic black children had significantly higher BLLs than non-minority children even after adjusting for age of child and age of housing; however, significant differences in BLLs among the different races were not observed for children living in housing built prior to 1950. More notably, mean ln[BLL] was significantly associated with lead dust levels, which is consistent with the result that children who attend daycare/preschool have significantly lower BLLs than children who do not. These results demonstrate a complex interaction between several demographic, sociodemographic and housing characteristics in predicting BLLs of U.S. children.