A large-scale, prospective study of the effects of lead exposure on delinquency adds to a growing body of evidence linking high lead levels to criminal behavior.
Kim Dietrich and colleagues began following their subjects between 1979 and 1985, before the children were born. Blood lead levels were provided by the mothers during pregnancy, and the children's lead levels were checked every three months from birth to age six. The majority of the children were African-American, and 53 percent were male.
Between 1997 and 1999, 195 of the now-adolescent children were re-evaluated. "Adolescents with the highest blood lead concentrations when they were first graders reported, on average, 4.5 more delinquent acts in the previous 12 months compared to children with the lowest blood lead concentrations as first graders," Dietrich et al. say. Exposure to lead correlated with antisocial behavior even after the researchers adjusted for birth weight, parental IQ, social class, and quality of home environment.
The researchers conclude, "It appears that the neurodevelopmental effects of this avoidable environmental disease of childhood may not be limited to declines in IQ or academic abilities."
The study supports earlier findings of Herbert Needleman (see Crime Times Vol. 6, No. 3, 2000, p. 2), (see related article, Crime Times, 2000, Vol. 6, No. 3, Page 2), who reported in a large-scale study in 2000 that convicted juveniles were nearly twice as likely as control subjects to have high bone-lead levels.
"Early exposure to lead and juvenile delinquency," K.N. Dietrich, R. M. Douglas, P. A. Succop, O. G. Berger, and R. L. Bornschein, Neurotoxicology and Teratology, Vol. 23, No. 6, November-December 2001, 511-8. Address: K. N. Dietrich, Department of Environmental Health, Division of Epidemiology and Biostatistics, University of Cincinnati College of Medicine, Cincinnati, OH 45267-0056.
"Study links lead exposure to antisocial behavior," press release, Children's Hospital Medical Center of Cincinnati, February 28, 2002.