Abstract

Introduction: There have been a number of recent claims in the literature that lead exposure may make a strong contribution to criminal behaviour.

Objectives: To examine linkages between exposure to lead in childhood and crime in late adolescence/early adulthood, to: (a) determine whether higher levels of lead exposure were associated with increased levels of criminal behaviour; and (b) estimate the extent to which lead exposure was responsible for increases in criminal behaviour.

Methods: Negative binomial regression models were fitted using data from a longitudinal birth cohort of New Zealand-born children studied from birth to the age of 21.

Results: There were statistically significant (p < .05) bivariate associations between dentine lead levels assessed at ages 6-9 and both: (a) officially recorded violence/property convictions (ages 14-21); and (b) self-reported violent/property offending (ages 14-21). The mean rate of official convictions was 1.89 (SD = 6.86) and the mean rate of self-reported offences was 15.24 (SD = 49.24) for those with the highest level of exposure. Those with the lowest level of exposure had a mean rate of convictions of 0.0, and a mean rate of self-reported offending of 1.97 (SD = 6.34). Adjustment for potentially confounding factors reduced the magnitude of these associations, but the associations between lead exposure and crime remained statistically significant. Further analyses suggested that the associations were largely explained by the linkages between lead exposure and educational underachievement. Lead exposure accounted for less than 1% of the variance in criminal behaviour.

Conclusions: The results of the present study suggest that, while lead exposure was associated with criminal behaviour, the associations were somewhat weak, and were largely explained by linkages between lead exposure and educational underachievement.