Recent trends in childhood blood lead levels.

Blood lead levels in children in the United States have declined through 1994, the date of the most recent National Health and Nutrition Examination Survey. In this investigation, the authors analyzed whether blood lead levels have changed since 1994 and quantified the magnitude of any change. The authors evaluated blood lead levels from 12 longitudinal data sets from 11 states and 1 city. Geometric mean blood lead levels declined between 4%/year and 14%/year in 8 of the data sets. No differences in decline rates were observed between data sets from states that had universal screening as a goal or that included repeat measures for an individual child and those data sets that did not. The authors' best estimate for these populations was a decline rate of 4-7%/year, which was comparable to the decline rate prior to 1994.