yongrel
05-28-2008, 11:00 AM
Childhood lead exposure can predict criminality
01:00 28 May 2008
NewScientist.com news service
Alison Motluk
http://www.newscientist.com/article/dn13989-childhood-lead-exposure-can-predict-criminality.html?DCMP=ILC-hmts&nsref=news8_head_dn13989
Children exposed to lead early in life are more likely to be in trouble with the law as adults.
Lead contamination most often arises from the dust and soil, but can also come from lead water pipes or environmental pollution. Studies have consistently found associations between lead exposure in childhood and subsequent antisocial behaviour, but there have always been problems in determining causality.
Now Kim Dietrich at the University of Cincinnati College of Medicine and his colleagues have looked prospectively at how lead levels affect the risk of being arrested in adulthood. They recruited 250 pregnant women from a poor lead-contaminated inner-city district in Cincinnati.
The researchers took blood samples from the women early in pregnancy, then sampled the blood of the children four times a year till age 5, and then twice a year until they were about 7 years old.
Increased arrests
Years later, the researchers checked public records to see if their subjects had been arrested since reaching the age of 18, and if so, how many times and for what. Independent reviewers coded them into categories, such as violent offences, drug offences and fraud.
After controlling for factors including maternal IQ, maternal arrest rates, parenting style and socioeconomic factors, they found that prenatal and childhood lead concentrations in the blood predicted likelihood of adult arrest.
A 5 microgram/decilitre increment in average childhood blood lead level, for instance, increased the rate of arrest for violent crimes by 26%. And high prenatal blood levels predicted the total number of adult arrests.
Dose-dependent effect
Lead can interfere with the brain by impairing synapse formation and disrupting neurotransmitters, such as dopamine and serotonin. It also appears to permanently alter brain structure.
In a companion study, the researchers used magnetic resonance imaging to look at the brains of some of these same individuals.
They found that, here too, lead had a dose-dependent effect – the more lead a person had been exposed to as a child, the smaller the brain regions in frontal areas. These are regions involved in judgement, emotional regulation and impulse control, among other things.
"It's time to blame lead," says Dietrich.
Preventable risk
"Even if the contribution of lead to arrest risk is small," points out David Bellinger, at Harvard Medical School, Boston, Massachusetts, US, in a comment on the paper, "it has a special status in that, in contrast to most other known risk factors for criminality, we know full well how to prevent it."
The Centers for Disease Control says that blood levels above 10 micrograms are unsafe. The good news is that both childhood blood lead levels and crime have declined in the US.
In Ohio, for instance, where this study was conducted, only 2.3% of children under age 6 had blood lead levels exceeding CDC recommendations in 2006, compared with 16.6% of children in 1997.
The mean childhood blood level of these study participants was 13 mcg/dl, and ranged from 4 to 37 mcg/dl. Many researchers say even 5 mcg/dl can put a child at risk.
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Damn, I knew I shouldn't have been chewing on those paint chips.
01:00 28 May 2008
NewScientist.com news service
Alison Motluk
http://www.newscientist.com/article/dn13989-childhood-lead-exposure-can-predict-criminality.html?DCMP=ILC-hmts&nsref=news8_head_dn13989
Children exposed to lead early in life are more likely to be in trouble with the law as adults.
Lead contamination most often arises from the dust and soil, but can also come from lead water pipes or environmental pollution. Studies have consistently found associations between lead exposure in childhood and subsequent antisocial behaviour, but there have always been problems in determining causality.
Now Kim Dietrich at the University of Cincinnati College of Medicine and his colleagues have looked prospectively at how lead levels affect the risk of being arrested in adulthood. They recruited 250 pregnant women from a poor lead-contaminated inner-city district in Cincinnati.
The researchers took blood samples from the women early in pregnancy, then sampled the blood of the children four times a year till age 5, and then twice a year until they were about 7 years old.
Increased arrests
Years later, the researchers checked public records to see if their subjects had been arrested since reaching the age of 18, and if so, how many times and for what. Independent reviewers coded them into categories, such as violent offences, drug offences and fraud.
After controlling for factors including maternal IQ, maternal arrest rates, parenting style and socioeconomic factors, they found that prenatal and childhood lead concentrations in the blood predicted likelihood of adult arrest.
A 5 microgram/decilitre increment in average childhood blood lead level, for instance, increased the rate of arrest for violent crimes by 26%. And high prenatal blood levels predicted the total number of adult arrests.
Dose-dependent effect
Lead can interfere with the brain by impairing synapse formation and disrupting neurotransmitters, such as dopamine and serotonin. It also appears to permanently alter brain structure.
In a companion study, the researchers used magnetic resonance imaging to look at the brains of some of these same individuals.
They found that, here too, lead had a dose-dependent effect – the more lead a person had been exposed to as a child, the smaller the brain regions in frontal areas. These are regions involved in judgement, emotional regulation and impulse control, among other things.
"It's time to blame lead," says Dietrich.
Preventable risk
"Even if the contribution of lead to arrest risk is small," points out David Bellinger, at Harvard Medical School, Boston, Massachusetts, US, in a comment on the paper, "it has a special status in that, in contrast to most other known risk factors for criminality, we know full well how to prevent it."
The Centers for Disease Control says that blood levels above 10 micrograms are unsafe. The good news is that both childhood blood lead levels and crime have declined in the US.
In Ohio, for instance, where this study was conducted, only 2.3% of children under age 6 had blood lead levels exceeding CDC recommendations in 2006, compared with 16.6% of children in 1997.
The mean childhood blood level of these study participants was 13 mcg/dl, and ranged from 4 to 37 mcg/dl. Many researchers say even 5 mcg/dl can put a child at risk.
**************************************
Damn, I knew I shouldn't have been chewing on those paint chips.