Lead and violent crime

For the past three decades, researchers from the University of Cincinnati have been following 240 people from predominately African American neighborhoods of Cincinnati with high lead contamination. With each passing year, more is revealed about how lead in the environment affects health and behavior. Now, new research reveals that, even at low levels, lead exposure in early development shrinks key areas of the brain, and is linked with violent crime. "Living on Earth’s Ashley" Ahearn traveled to Cincinnati and filed this report.

Lead is a neurotoxin, linked to disorders such as lower IQ and Attention Deficit Hyperactivity Disorder. And now there is more compelling evidence linking lead exposure in the womb and early childhood with violent crime later in life.

These latest findings come from researchers at the University of Cincinnati and Cincinnati Children’s Hospital. For almost three decades they have been following a group of Cincinnati residents – more than 90 percent of them African American. They grew up in neighborhoods with high lead contamination – mostly from the dust of deteriorated lead paint in older apartments and houses.

Serving as a police officer for 27 years, Cincinnati Councilman Cecil Thomas watched the violence grow, seemingly without rhyme or reason. The new lead research gives him one potential explanation:

"The environment as a totality really pretty much dictates a lot of our problems as relates to crime and things of that nature. Because when you look at areas of our city that are most affected by crime and then you look at buildings that are tainted with lead poisoning paint, then you have to start thinking well maybe there is a link between the effects of lead poising and the overall crime rates, especially in the inner city neighborhoods."

Dr. Kim Dietrich and his team at the University of Cincinnati are working to answer just that question. They took the criminal records of the 250 study participants and compared the numbers of violent crimes with the levels of lead each participant had been exposed to throughout his or her life:

"What we found was interesting. The most robust and significant associations were between early exposure to lead and arrests involving violent acts, some sort of violent aggressive behavior."

Dr. Kim Cecil is a professor of radiology at the University of Cincinnati and works with Dr. Dietrich. She’s found that children with higher lead levels have smaller frontal lobes as they reach adulthood. She says that may be because lead takes the place of calcium in the brain:

"It interferes with many enzymes that preserve the neurons in the brain so it stops the healthy maintenance of neurons and thus neurons can die. And it looks like a shriveled up brain. So in a way it looks like a person who’s much, much older."

Older – as in closer to senility – not older – as in more mature. Young men show more volume loss to the frontal lobe than young women exposed to similar levels of lead.

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