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.
Childhood exposure to lead is now linked with adult criminal activity. (Photo courtesy FBI)
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.
These records provided information about the nature and extent of arrests and were coded by category - violent, property, drugs, fraud, obstruction of justice, serious motor vehicle, disorderly conduct and other offenses.
Researchers found that individuals with increased blood-lead levels before birth and during early childhood had higher rates of arrest for both violent and total crimes than the rest of the study population after age 18.
Approximately 55 percent of the subjects had at least one arrest. The majority of arrests involved violence. Drugs accounted for 28 percent of the arrests, while serious motor vehicle violations accounted for 27 percent.
Dietrich says that although both environmental lead levels and crime rates in the United States have dropped in the past 30 years, they have not dropped in a uniform way.
A work crew removes lead paint from an older building. (Photo credit unknown)
According to the most recent U.S. National Health and Nutrition Examination Survey, more than 434,000 children between the ages of one and five have elevated blood lead levels.
This research is part of a long-term lead exposure study conducted through the Cincinnati Children’s Environmental Health Center, a collaborative research group funded by the National Institute of Environmental Health Sciences and U.S. Environmental Protection Agency that involved scientists from the UC College of Medicine and Cincinnati Children’s Hospital Medical Center.
Dietrich and his colleagues report their findings in the May 27, 2008, issue of the journal PLoS Medicine. Coauthors include M. Douglas Ris, PhD, Richard Hornung, PhD, Stephanie Wessel, Bruce Lanphear, MD, Mona Ho, and Mary Rae, PhD.
The federal government banned lead-based paint from housing in 1978, but many homes built before 1978 have been covered with paint containing lead.
Soil can pick up lead from exterior paint or from other sources such as past use of leaded gas in cars, and children playing in yards can ingest or inhale lead dust. Leaded gas was banned in the United States in 1996.
Household dust can pick up lead from deteriorating lead-based paint or from soil tracked into a home.
Homes may have plumbing containing lead or lead solder. You cannot see, smell or taste lead, and boiling the water will not get rid of lead. The U.S. EPA recommends contacting your local health department or water supplier to find out about testing your water.
To find out more about lead exposure from the federal Agency for Toxic Substances, click here. To see what the U.S. EPA has to say about lead, click here. For advice on funding for lead paint removal in Cincinnati, click here.
Copyright Environment News Service (ENS) 2008. All rights reserved.