Health Story

03 December 2008 02:10 BST

Childhood lead exposure linked to crime

Children who are exposed to lead at an early age could be more likely to commit crime when they are adults, a new study suggests.

Researchers in America say they have found the first evidence of a direct link between prenatal and early-childhood lead exposure and an increased risk for criminal behaviour, including violent crime, later in life.

The team from the University of Cincinnati found that elevated prenatal and postnatal blood-lead concentrations are associated with higher rates of criminal arrest in adulthood.

They studied 250 babies born to women living in poor areas of Cincinnati between 1979 and 1984.

This area was chosen as it had a high concentration of older lead-contaminated housing.

Blood lead levels were measured during pregnancy and then regularly until the children were six and a half years old, as an indication of their lead exposure.

This exposure was then correlated with local criminal justice records on how many times each of the 250 offspring had been arrested between becoming 18 years old and the end of October 2005.

The researchers found that increased blood lead levels before birth and during early childhood were associated with higher rates of arrest for any reason and for violent crimes.

For every 5ug/dl increase in blood lead levels at six years of age, the risk of being arrested for a violent crime as a young adult increased by almost 50 per cent.

Study co-author Dr John Wright said he was surprised at the findings, which are published in the journal PLoS Medicine.

"I did not expect we would see an effect, much less a substantive effect and even less likely a highly resilient effect," he explained.

"The fact that we are able to detect the effects from childhood exposures now into adulthood stands as a testament of lead's power to influence behaviour over a long period of time."

Commenting on the findings, Dr David Bellinger from Harvard Medical School - who was not involved in the research – said: "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."