High levels of lead in the blood of fetuses and young children has been linked for the first time to higher rates of criminal arrest in adulthood. The strongest association between childhood blood-lead level and criminal behavior was for arrests involving acts of violence, new research has found.
Based on long-term data from a childhood lead study in Cincinnati, Kim Dietrich, PhD, and his team at the University of Cincinnati found the first evidence of a direct link between prenatal and early-childhood lead exposure and an increased risk for criminal behavior later in life.
"Previous studies either relied on indirect measures of exposure or failed to follow subjects into adulthood to examine the relationship between lead exposure and criminal activity in young adults," explains Dietrich, principal investigator of the study and professor of environmental health at the University of Cincinnati.
"We have monitored this specific sub-segment of children who were exposed to lead both in the womb and as young children for nearly 30 years," he says.
"We have a complete record of the neurological, behavioral and developmental patterns to draw a clear association between early-life exposure to lead and adult criminal activity," says Dietrich.
Children can be exposed from eating lead-based paint chips or playing in contaminated soil. Lead can damage the nervous system, kidneys, and reproductive system.
"Aggressive or violent behavioral patterns often emerge early and continue throughout life," Dietrich says. "Identifying the risk factors that may place youth on an early trajectory toward a life of crime and violence should be a public health priority."
Dietrich says few studies have attempted to evaluate the consequences of childhood lead exposure as a risk of criminal behavior.
Study coauthor John Wright, PhD says he had limited expectations for how strong a correlation between lead exposure and criminality could be established. A member of the university’s criminal justice faculty who studies the impact of factors like genetics, psychology and biology on criminality, Wright was a skeptic at first.
"I did not expect we would see an effect, much less a substantive effect and even less likely a highly resilient effect," says Wright. "The fact that we are able to detect the effects from childhood exposures now into adulthood stands as a testament of lead’s power to influence behavior over a long period of time."
At four prenatal clinics between 1979 and 1984, the researchers recruited pregnant women living in Cincinnati neighborhoods with a higher concentration of older, lead-contaminated housing.
Of the original 376 newborns recruited, 250 were tracked for the current study. Dietrich’s team has monitored this group of children since birth to assess the long-term health effects of early-life lead exposure.
Researchers measured blood-lead levels during pregnancy and then at regular intervals until the children were six and a half years old to calculate cumulative lead exposure.
Blood-lead level data was correlated with public criminal arrest records from a search of Hamilton County, Ohio criminal justice records.