MRI images reveal volume loss in regions of the brain responsible for decision making, reasoning and judgement in people exposed to lead during early development. (photo: University of Cincinnati, Cincinnati Children's Hospital)
For the past three decades, researchers from the University of Cincinnati have been following 240 people from largely 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 also linked with violent crime. Living on Earth’s Ashley Ahearn traveled to Cincinnati and has our story.
GELLERMAN: It’s Living on Earth. I’m Bruce Gellerman. Recent reports about lead in toys have raised fears and renewed concerns about what it does to our children. We’ve known for years that lead is a neurotoxin. That it can lower a child’s IQ, lead to behavioral problems and cause Attention Deficit Hyperactivity Disorder. But lead in toys isn’t the main problem; it’s lead-based paint in old homes that causes the most harm in kids.
That’s why for the past three decades, researchers at the University of Cincinnati and Cincinnati Children's Hospital have been studying a group of people – mostly African Americans – who live in poor neighborhoods contaminated with lead. What the researchers have discovered is that exposure to lead, even at low doses, reduces the size of developing brains, and when kids grow up they’re more prone to commit violent crimes. We have this report from Living on Earth's Ashley Ahearn.
[MRI MACHINE TICKING NOISE]
AHEARN: At Children’s Hospital in Cincinnati, Damon lies inside the giant white cylinder of an MRI machine as it takes thousands of pictures of his brain.
AHEARN: How’d it go in there?
AHEARN: Good? Did you fall asleep?
DAMON: Yeah, for probably about a minute or so. I was tryin’. I was real tired.
AHEARN: At 28 years old, Damon is one of 240 people with high blood lead levels that researchers at the University of Cincinnati have been monitoring since before they were born.
DAMON: I remember the cab rides, the trips with my mama. It’s just something I been doing since I was a little boy and it continues.
His lead exposure makes his brain interesting to Kim Cecil, a professor of radiology at the University of Cincinnati. She’s studying the ways lead affects the size and health of the brain – the frontal lobe in particular.
CECIL: The frontal lobe is the part that probably makes us the most human in that it’s executive functioning, attention, inhibition, reasoning, judgment, kind of overall control.
CECIL: It reduces a lot of special receptors, it interferes with many enzymes that preserve the neurons in the brain, so it stops the healthy maintenance of neurons and then neurons can die.
AHEARN: What does that look like? If you were to open up a skull of someone who had a really high lead exposure level, what would I see?
CECIL: Atrophy. And it looks like a shriveled up brain. So in a way it looks like a person who’s much, much older.
AHEARN: Young men like Damon show more volume loss to the frontal lobe than young women exposed to similar levels of lead. Cecil published her findings in the most recent issue of the Public Library of Science Medicine.
Other new research on the same group of study participants shows that even at levels well below government standards, lead exposure during early development may be linked to criminal arrests in young adulthood.
Kim Dietrich is a Professor of Environmental Health at the University of Cincinnati and co-author of the study.
DIETRICH: 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.
AHEARN: Violent, impulsive acts – the kind of behavior that might result from damage to the part of the brain responsible for self-restraint and decision-making.
Dietrich’s team found that for every increase of five micrograms per deciliter of lead in a child’s blood, there was a 30 percent rise in their arrests for violent offenses.
And because male and female brains develop differently in the womb, the research suggests male brains are more vulnerable to lead. But females are not immune.
[SOUND OF RAIN; FRONT DOOR OPENING; WOMAN SAYING “HI MISS ASHLEY, HOW YOU DOIN’?”; DOOR CLOSES; AHEARN SAYING “I’M GOOD; A LITTLE WET”]
AHEARN: It’s pouring rain when I get to Laquisha’s place in Northern Cincinnati. Music blares as she welcomes me in.
[HIP HOP PLAYING]
AHEARN: Laquisha’s 23 and she’s been participating in the lead study since she was about a year old. She says, looking back, she can see how lead has affected her behavior.
LAQUISHA: Like, when I was young, when I couldn’t get my way, I, like, tear down the whole bedroom. I break mirrors and everything, I’d pull my hair out and then at the end I be wishin’ I never did it all.
AHEARN: Laquisha’s expressive brown eyes look away as she tells me about another time when her temper got her into trouble. She was at an Arby’s restaurant a few years ago when her boyfriend got in a fight with the girl behind the counter.
Laquisha says she was trying to pull him away when two cops, who were eating there, got involved. When they tried to arrest her, Laquisha lost it.
LAQUISHA: And I was goin crazy, I was kickin, screamin’. I wouldn’t let him get the other handcuff on me so he slammed me and came down with his knee on my stomach so I grabbed his belt and the collar of his shirt and I flipped him on his head. And I was hitting him with my handcuff that was free and then somehow he got me in a headlock. He was punching me in my head, we was just exchangin’. At that point in time I just wasn’t thinkin’.
AHEARN: Laquisha spent two years in jail for her crime, and she takes full responsibility for her actions.
She’s working at McDonald’s now, and trying to pass her GED. But she says she has a tough time focusing.
There’s no doubt in her mind that lead played a part in her violent actions.
[DOOR OPENING; KEYS JANGLING; MAN SAYS “HOW YOU DOIN’ OFFICER?”]
AHEARN: At the Cincinnati Police Department, S. Gregory Baker is director of community relations. He’s familiar with the lead study, and isn’t surprised there’s a link between lead exposure and violent crime.
BAKER: We’ve seen that a lot of these homicides are very impulsive, that they’re not necessarily pre-meditated. They’re what you and I would probably think really wouldn’t merit shooting and killing somebody.
AHEARN: But Baker says when you arrest someone, there’s no way of knowing if lead exposure is affecting their behavior.
BAKER: I mean that’s just not something that we would deal with as far as they had high lead. I think it’s just the causative piece. I mean there really is nothing tangible for us to do about that.
AHEARN: The effects of lead exposure are intangible, although the findings of the team at the University of Cincinnati are changing that.
Kim Dietrich says discovering a link between lead and violent crime doesn’t justify the behavior, but it does help us better understand where it might be coming from.
DIETRICH: The community that these children are growing up in, and these adults are living in, provide many opportunities to engage in criminal behavior. And in some cases lead is pulling the trigger or resulting in the final aggressive act.
AHEARN: For Living on Earth, I’m Ashley Ahearn in Cincinnati, Ohio.
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