Dispelling previous findings, a new study has said that children exposed to lead at a young age are less likely to be involved in criminal practices later in adulthood. Responses toward lead exposure should focus on health consequences, and not potential criminal consequences, the study suggested. Lead is a neurotoxin with well-documented effects on health. Previous studies detected associations between childhood blood lead level and criminal offending owing to the toxic effect of lead disproportionately affecting people with low socioeconomic status.

However, the new study weakens the association between lead exposure and adult criminal behaviour, the researchers said. “There is no clear association between higher childhood blood lead levels and a greater risk for criminal behaviour (a dose-response relationship) in settings where blood lead levels are similar across low and high socioeconomic status,” said Amber L Beckley, from the Duke University, in North Carolina. For the study, detailed in the journal JAMA Pediatrics, the team involved 553 individuals from New Zealand, whose blood lead levels were measured at age 11.

There cumulative criminal conviction, self-reported criminal offending, recidivism (repeat conviction), and violence were followed up to age 38. The researchers removed low socioeconomic status as a factor because high blood lead levels were observed among children from all socioeconomic groups.

The results showed that childhood lead exposure was weakly associated with conviction and self-reported criminal offending up to age 38. Further, lead exposure was also not associated with recidivism or violence.