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.