Study Finds Weak Link Between Lead Exposure, Criminality

For decades, researchers have mulled a link between childhood exposure to lead and criminal behavior. But a new long-term study of New Zealanders published in a medical journal finds only a modest association in teens that diminished later in life.

Childhood lead exposure is not consistently associated with criminal behavior later in life, according to Courthouse News Service, citing a report published Tuesday in the journal JAMA Pediatrics. The report should ease the minds of parents in areas where children have been exposed to high levels of lead in their drinking water. After adjusting for socioeconomic status, a team of researchers found a weak connection between childhood lead exposure and subsequent criminal offenses. Lead exposure was also not associated with recidivism or violence, according to the study. Childhood lead exposure has been associated with abnormalities in brain structures, childhood behavioral problems and lasting declines in intelligence, the authors write.

“One hypothesized behavioral effect of high levels of lead exposure is increased antisocial and criminal behavior,” they added. To test this theory, the team monitored 553 people born in New Zealand between 1972 and 1973 for more than three decades. After measuring the participants’ blood lead levels (BLL) when they were 11, the team tracked the group’s self-reported criminal offending up to age 38. In the end, 154 participants were convicted of at least one crime. “The variety of self-reported offenses was weakly associated with BLL and only reached statistical significance at ages 15, 18, and 26 years,” the study reads. “After controlling for sex, the association between higher BLL and variety of self-reported offenses remained weak and was statistically significant only at assessment age 15 years.”