Lead poisoning is linked to juvenile delinquency

Children are at a greatly increased risk of developing delinquent behaviour and ending up in juvenile courts if they are exposed to lead.

Children are at a greatly increased risk of developing delinquent behaviour and ending up in juvenile courts if they are exposed to lead.

Research published yesterday at a conference on children's behaviour shows that youths convicted in juvenile courts had much higher mean concentrations of lead in their blood than non-delinquent children. Although it is the first study to show a direct link between lead exposure and criminality, it is part a growing body of evidence linking lead to poorer intelligence and communication skills and behavioural problems such as truancy, vandalism and bullying.

A second study presented at the Paediatric Academic Societies conference in Boston, Massachusetts, showed that lead can adversely affect children's brain function at much lower levels than previously believed, indicating that millions more children are unknowingly suffering damage from lead exposure.

Herbert Needleman, professor of child psychiatry and paediatrics at the University of Pittsburgh and author of the first study, said: "This study provides further evidence that delinquent behaviour can be caused, in part, by childhood exposure to lead. Of all the causes of juvenile delinquency, lead exposure is perhaps the most preventable."

Professor Needleman's previous work was instrumental in bringing about the removal of lead from paint and petrol. His new findings, based on 216 youths convicted in juvenile court and compared with 201 high school children, held true regardless of race or sex.

In Britain, concern about lead and its effect on children's development was first triggered in 1975 when research showed that Birmingham residents living near the M6 and A38 junction had high levels of lead in their blood, with detrimental effects. In January 2000, lead additives in petrol were banned completely, but is still widely present in water pipes.

The second study presented at the conference shows that children with lead levels as low as 2.5 micrograms per decilitre were found to have problems with basic skills. "Cognitive defects in reading, maths, visual construction skills, and short-term memory are associated with blood-lead concentration considerably lower than 10 micrograms per decilitre, the level that is considered 'acceptable'," said Dr Bruce Lanphear, of the Children's Hospital Medical Centre, in Cincinnati, Ohio, who conducted the research.

The findings indicate that millions more children and teenagers have been affected by lead poisoning than thought. The researchers studied 4,853 children, aged 6 to 16, between 1988 and 1994 and found their cognitive functions in reading, maths, visual construction and short-term memory were poorer the higher their blood-lead levels. This applied to maths and reading scores at blood-lead concentrations as low as 2.5 micrograms per decilitre.

Dr Lanphear said: "Despite the dramatic decline over the last two decades in the prevalence of children who have blood-lead concentrations above 10 micrograms per deci-litre, these data underscore the increasing importance of prevention as the consequen-ces of lower blood-lead concentrations are recognised."