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Abstract: Recent literature [e.g. Canfield RL, Henderson CR, Cory-Slechta DA, Cox C, Jusko TA, Lanphear BP. Intellectual impairment in children with blood lead concentrations below 10mg per deciliter. New Engl J Med 2003;348(16):1517–1526; Lanphear BP, Hornung R, Khoury J, Yolton K, Baghurst P, Bellinger DC, Canfield RL, Dietrich KN, Bornschein R, Greene T, Rothenberg SJ, Needleman HL, Schnaas L, Wasserman G, Graziano J, Roberts R. Low-level environmental lead exposure and children''s intellectual function: an international pooled analysis. Environ Health Perspect 2005;113(7):894–899] has suggested the existence of a supra-linear dose–response relationship between environmental measures such as blood lead concentrations and IQ. This communication explores the mathematical requirements placed on such dose–response relationships when the environmental measure, or independent variable, is lognormally distributed and the effect, or dependent variable, is normally distributed. Results of the analyses show that a supra-linear slope is a required outcome of correlations between data distributions where one is lognormally distributed and the other is normally distributed. The analysis shows that caution should be taken in assigning biological significance to supra-linear dose–response relationships in these instances. Detailed analyses of such data sets should be conducted to determine if the magnitude of supra-linear slopes are more or less than mathematically required, and from there to consider biological significance. [Copyright &y& Elsevier]

Observed blood lead levels for young children from several communities are compared with blood lead levels predicted for those communities using the USEPA[sup s] Integrated Exposure Uptake Biokinetic (IEUBK) Model. In contrast to the comparisons described elsewhere, the blood lead levels observed in the communities considered here are not well represented by the model's predictions. The model's predictions for Midvale, UT; Sandy, UT; Cincinnati, OH; and a recent data set for Palmerton, PA, show considerable deviation from observation both for the geometric mean blood lead level and the percent of blood lead levels above 10 μg/dL. Various adjustments in the model to consider play-area soils, site-specific geometric standard deviations and the time children spend away from their homes do not substantially improve the comparisons to observation. It is difficult to predict a priori the data sets for which the model will yield adequate predictions. This reduces the value of the model for use in communities where blood lead measurements have not been made, and suggests that caution should be exercised when using the model to set soil lead cleanup levels or to predict the result of remediation. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

This paper presents a model for predicting blood lead levels in adults who are exposed to elevated environmental levels of lead. The model assumes a baseline blood lead level based on average blood lead levels for adults described in two recent U.S. studies. The baseline blood lead level in adults arises primarily from exposure to lead in diet. Media-specific ingestion and absorption parameters are assessed for the adult population, and a biokinetic slope factor that relates uptake of lead into the body to blood lead levels is estimated. These parameters are applied to predict blood lead levels for adults exposed to a hypothetical site with elevated lead levels in soil, dust and air. Blood lead levels ranging from approximately 3-57 µg/dl are predicted, depending on the exposure scenarios and assumptions. [ABSTRACT FROM AUTHOR]