Exposure of US Children to Residential Dust Lead, 1999-2004: II. The Contribution of Lead-Contaminated Dust to Children's Blood Lead Levels

BACKGROUND: The U.S. Centers for Disease Control and Prevention collected health, housing, and environmental data in a single integrated national survey for the first time in the United States in 1999-2004. OBJECTIVES: We aimed to determine how floor dust lead (PbD) loadings and other housing factors influence childhood blood lead (PbB) levels and lead poisoning. METHODS: We analyzed data from the 1999-2004 National Health and Nutrition Examination Survey (NHANES), including 2,155 children 12-60 months of age with PbB and PbD measurements. We used linear and logistic regression models to predict log-transformed PbB and the odds that PbB was >= 5 and >= 10 mu g/dL at a range of floor PbD. RESULTS: The population-weighted geometric mean (GM) PbB was 2.0 mu g/dL (geometric standard error = 1.0). Age of child, race/ethnicity, serum cotinine concentration, poverty-to-income ratio, country of birth, year of building construction, floor PbD by floor surface and condition, windowsill PbD, presence of deteriorated paint, home-apartment type, smoking in the home, and recent renovation were significant predictors in either the linear model [the proportion of variability in the dependent variable accounted for by the model (R-2) = 40%] or logistic model for 10 mu g/dL (R-2 = 5%). At floor PbD = 12 mu g/ft(2), the models predict that 4.6% of children living in homes constructed before 1978 have PbB 10 mu g/dL, 27% have PbB >= 5 mu g/dL, and the GM PbB is 3.9 mu g/dL. CONCLUSIONS: Lowering the floor PbD standard below the current standard of 40 mu g/ft(2) would protect more children from elevated PbB.