Research Links Lead Exposure and Criminal Behavior Risk

A study from the University of Cincinnati reports the first evidence of a direct link between prenatal and early-childhood lead exposure and an increased risk for criminal behavior later in life. Based on long-term data from a childhood lead study in Cincinnati, Ohio, Kim Dietrich, Ph.D., and his team have determined that elevated prenatal and postnatal blood-lead concentrations are associated with higher rates of criminal arrest in adulthood.

"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," said Dietrich, principal investigator of the study and professor of environmental health at the university. "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."

Dietrich and his colleagues report their findings in the May 27 issue of the journal PLoS Medicine.

This new study 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 involve scientists from the UC College of Medicine and Cincinnati Children's Hospital Medical Center.

Led by Dietrich, researchers recruited pregnant women living in Cincinnati neighborhoods with a higher concentration of older, lead-contaminated housing. Recruitment took place at four prenatal clinics between 1979 and 1984. Dietrich's team has monitored this population group since birth.

Of the original 376 newborns recruited, 250 were identified for the current study. Researchers measured blood-lead levels during pregnancy and then at regular intervals until the children were 6 ½ years old to calculate cumulative lead exposure.

Blood-lead level data was then 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 which involved drugs (28 percent) or serious motor vehicle violations (27 percent). The strongest association between childhood blood-lead level and criminal behavior was for arrests involving acts of violence.

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 done so in a uniform way.

"Lower income, inner-city children remain particularly vulnerable to lead exposure," he explains. "Although we've made great strides in reducing lead exposure, our findings send a clear message that further reduction of childhood lead exposure may be an important and achievable way to reduce violent crime.

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