Criminality Linked to Infantile Lead Exposure

A new study investigating the relation between lead exposure during childhood and later antisocial behavior showed that lead contamination can be used to predict whether or not an individual will get in trouble with the law during adulthood. The investigation was led by Kim Dietrich from the University of Cincinnati College of Medicine who had collected blood samples from 250 pregnant women living in the lead contaminated areas of Cincinnati.

New blood samples were then collected from the children at the age of five and seven, and were then compared to the children's police records at the age of eighteen and the severity of their offences. Other significant factors for the study included the IQ coefficient of the mothers, whether or not they had ever been arrested, the socioeconomic status of the family raising the child and the lead concentrations in their blood.

The results revealed that an average increase of 5 microgram/decilitre of lead concentration in the blood could lead to an increase in criminality by up to 26 percent, while the lead concentration in the parents' blood could be used to predict the number of arrests during adulthood.

Lead is toxic to the human body, as it prevents to some extent the formation of synapses and blocks neurotransmitters like dopamine and serotonin, thus severely affecting the correct development of the frontal areas of the brain, which control the emotional, judgment and impulse responses.

"It's time to blame lead", says Dietrich.

"Even if the contribution of lead to arrest risk is small, 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", says David Bellinger from the Harvard Medical School, who did not participate in the study.

Lead concentrations higher than 10 micrograms/decilitre of blood are considered to be unsafe for the child, but the same study shows that the lead concentrations in the US are in decline. A decade ago, 16.6 percent of the children in Ohio under the age of six had high lead concentrations, as opposed to the current 2.3 percent.

The average concentration of lead in the blood of the participants in the study was of 13 micrograms/decilitre and varied between 4 to 37 micrograms/decilitre.