Association of childhood blood lead levels with firearm violence perpetration and victimization in Milwaukee

Abstract

Childhood lead exposure impairs future decision-making and may influence criminal behavior, but its role in future firearm violence is unclear. Using public health, education, and criminal justice datasets linked at the individual level, we studied a population-based cohort of all persons born between June 1, 1986 and December 31, 2003 with a valid blood lead test before age 6 years and stable Milwaukee residency (n = 89,129). We estimated associations with firearm violence perpetration (n = 553) and victimization (n = 983) using logistic regression, adjusting for temporal trends, child sex, race, and neighborhood socioeconomic status. Increasing risks for firearm violence perpetration and victimization were found in each higher category of blood lead compared to the lowest, after adjusting for confounding. For perpetration, risk ratios (RR) for increasing comparisons of mean blood lead in categories of ≥5 < 10, ≥10 < 20, and ≥20 μg/dL compared to persons with mean blood lead < 5 μg/dL, were: RR 2.3 (95% CI 1.6, 3.3), RR 2.5 (95% CI 1.7, 3.9), and RR 2.8 (95% CI 1.8, 4.4). For victimization, the same increasing categoric comparisons were: RR 1.8 (95% CI 1.4, 2.3), RR 2.4 (95% CI 1.8, 3.2), RR 3.3 (95% CI 2.4, 4.5). The proportion of firearm violence attributable to blood lead ≥5 μg/dL was 56% for perpetration and 51% for victimization. In Milwaukee, during a period of high lead exposures, childhood levels may have substantially contributed to adult firearm violence. While we cannot definitively conclude causality, the possibility that over half of firearm violence among this sample might be due to lead exposure suggests the potential importance of lead exposure reduction in firearm violence prevention efforts.