How Lead Exposure Relates to Temporal Changes in IQ, Violent Crime, and Unwed Pregnancy

How Lead Exposure Relates to Temporal Changes in IQ, Violent Crime, and Unwed Pregnancy Rick Nevin SEPTEMBER 15, 1999 Notice: This is an author’s version of a work that was accepted for publication by Environmental Research. Changes that resulted from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Environmental Research, Volume 83, Issue 1, May 2000, Pages 1-22. Page 1 How Lead Exposure Relates to Temporal Changes in IQ, Violent Crime, and Unwed Pregnancy This study compares changes in children’s blood lead levels in the United States with subsequent changes in IQ, based on norm comparisons for the Cognitive Abilities Test (CogAT) given to representative national samples of children in 1984 and 1992. The CogAT norm comparisons indicate shifts in IQ levels consistent with the blood lead to IQ relationship reported by an earlier study and population shifts in average blood lead for children under age six between 1976 and 1991. The CogAT norm comparisons also support studies indicating that the IQ to blood lead slope may increase at lower blood lead levels. Furthermore, long term trends in population exposure to gasoline lead were found to be remarkably consistent with subsequent changes in violent crime and unwed pregnancy.