Exposure of U.S. children to residential dust lead, 1999-2004: I. Housing and demographic factors.

Background: Lead-contaminated house dust is a major source of lead exposure for children in the United States. In 1999-2004, the National Health and Nutrition Examination Survey (NHANES) collected dust lead (PbD) loading samples from the homes of children 12-60 months of age.

Objectives: In this study we aimed to compare national PbD levels with existing health-based standards and to identify housing and demographic factors associated with floor and windowsill PbD.

Methods: We used NHANES PbD data (n=2,065 from floors and n=1,618 from windowsills) and covariates to construct linear and logistic regression models.

Results: The population-weighted geometric mean floor and windowsill PbD were 0.5 microg/ft2 [geometric standard error (GSE)=1.0] and 7.6 microg/ft2 (GSE=1.0), respectively. Only 0.16% of the floors and 4.0% of the sills had PbD at or above current federal standards of 40 and 250 microg/ft2, respectively. Income, race/ethnicity, floor surface/condition, windowsill PbD, year of construction, recent renovation, smoking, and survey year were significant predictors of floor PbD [the proportion of variability in the dependent variable accounted for by the model (R2)=35%]. A similar set of predictors plus the presence of large areas of exterior deteriorated paint in pre-1950 homes and the presence of interior deteriorated paint explained 20% of the variability in sill PbD. A companion article [Dixon et al. Environ Health Perspect 117:468-474 (2009)] describes the relationship between children's blood lead and PbD.

Conclusion: Most houses with children have PbD levels that comply with federal standards but may put children at risk. Factors associated with PbD in our population-based models are primarily the same as factors identified in smaller at-risk cohorts. PbD on floors and windowsills should be kept as low as possible to protect children.