Erratum: Low-level environmental lead exposureand children’s intellectual function: An international pooled analysis (Environ Health Perspect, (2005) 113(7), (894-899), 10.1289/ehp.7688)

The source of the errors in this article, which were limited to the Boston cohort, was twofold. Specifically, performance IQ data were used instead of full-scale IQ data for children in the Boston cohort. In addition, when converting log-transformed 6-, 18-, and 24-month blood lead measurements, a value of 1 was added instead of subtracted, making the blood lead values in the Boston cohort 2 lg=dL higher than they should have been. Consequently, there were small errors in the peak, early-childhood, and lifetime lead values in the Boston cohort. In turn, these errors resulted in small errors in the associations between blood lead levels and full-scale IQ for the Boston cohort and, thus, the pooled analysis as a whole. Accordingly, we reanalyzed the data using full scale IQ data and corrected blood lead levels for the Boston cohort and provide the corrected data and results in the revised text. There also were small changes in the model R² values used as the a priori criterion for identifying the blood lead metric that was the strongest predictor of IQ. We originally relied on the R² to select the blood lead metric for the primary analysis. However, the R² for concurrent (n = 1,333) and early childhood (n = 1,308) blood lead levels were very similar (R² =0:641 and 0.643, respectively) in the revised analysis. In both the original and revised analyses, the coefficient for concurrent blood lead levels had a smaller standard error and higher level of significance than early childhood blood lead levels. In the revised analysis, the standard error for concurrent blood lead and IQ was 0.530 and the level of significance was F = 87:5. In contrast, the standard error for early childhood blood lead and IQ was 0.597 and the level of significance was F = 35:1. We therefore retained concurrent blood lead level as the metric of choice and clarified this in the revised text. Importantly, the U.S. EPA and other investigators concluded that the data errors had only minor effects on the estimates and did not change the overall results or alter the scientific conclusions about the effects of low blood lead concentrations on cognitive function in young children (Crump et al. 2013; U.S. EPA 2013; Kirrane and Patel 2014). The authors regret the errors.