This study shows a very strong association between preschool blood lead and subsequent crime rate trends over several decades in the USA, Britain, Canada, France, Australia, Finland, Italy, West Germany, and New Zealand. The relationship is characterized by best-fit lags (highest R 2 and t-value for blood lead) consistent with neurobehavioral damage in the first year of life and the peak age of offending for index crime, burglary, and violent crime. The impact of blood lead is also evident in age-specific arrest and incarceration trends. Regression analysis of average 1985-1994 murder rates across USA cities suggests that murder could be especially associated with more severe cases of childhood lead poisoning.

Changes in IQ, Violent Crime, and Unwed Pregnancy This study compares changes in children's blood lead levels in the United INTRODUCTIONMany studies provide evidence of an inverse relationship between lead exposure and cognitive abilities (National Research Council). There is, however, disagreement about the IQ to blood lead slope (IQ points lost per one ug/dl increase in blood lead) and the influence of confounding variables (Schwartz; Pocock et al.). There is strong evidence that young children face the greatest risk of IQ losses due to lead exposure, especially during the first three years of life when basic cognitive abilities develop (Schwartz). Cognitive losses due to lead exposure during the first three years of life appear to be most evident in IQ tests taken some years later, around age 10 or older, when IQ scores are more stable and predictive of future outcomes (National Research Council; Schwartz). There is no consensus, however, on whether lead exposure is more strongly associated with verbal IQ, mathematical skills, or performance IQ (National Research Council).In addition to disagreements about the statistical significance of IQ losses due to lead exposure after controlling for confounding variables, there is a separate debate about the public policy significance of studies showing only a fraction of an IQ point lost per one ug/dl increase in blood lead. One argument in favor of public policy initiatives to reduce lead exposure is that small differences in mean IQ due to lead exposure can result in substantial differences in extreme values of the IQ and blood lead distributions. Differences in IQ have also been associated with differences in educational attainment and average lifetime earnings (National Research Council).A better understanding of the specific nervous system impacts of lead may be obtained from new epidemiological or laboratory studies, but the public policy debate has been largely resolved, with policy initiatives already successfully implemented to reduce lead exposure. The second and third National Health and Nutrition Examination Surveys (NHANES II and III) show that blood lead levels for children under age six declined by 75 percent between 1976 and 1991, due to declines Page 3 in lead in gasoline and solder in food and soft drink cans (Pirkle, et al.). This dramatic decline in national blood lead levels offers a new research perspective on both the statistical significance of lead's association with IQ after adjusting for covariates, and the public policy significance of IQ changes due to lead exposure. Has the decline in childhood blood lead since 1976 resulted in any subsequent increase in IQ levels that cannot be explained by confounding variables? If IQ levels have increased, what slope estimate for the IQ to blood lead relationship is suggested by this increase in IQ? Finally, have changes in blood lead been followed by subsequent changes in social behavior -with public policy significance -that might be associated with extreme values of the IQ and blood lead distributi...

No abstract

Previous estimates of childhood lead poisoning prevention benefits have quantified the present value of some health benefits, but not the costs of lead paint hazard control or the benefits associated with housing and energy markets. Because older housing with lead paint constitutes