Christian Hoover is the Co-Investigator of the Firearm Exposure Research Team at the Harvard Chan School of Public Health, where he is also a member of the Harvard Injury Control Research Center, student in the Health Policy Master’s program, and former project manager in the Department of Environmental Health.
When we reflect on gun risk, we think shootings. Since 2013, there have been over 35 thousand gun-related deaths in the US. But there’s a more insidious risk of harm — lead exposure.
Lead exposure is a big deal. It has been linked to mental and behavioral disorders, as well as early death by all causes. Lead exposure in children is one of the worst dangers facing young families. A single exposure in youth can impact a child for their entire life.
The way lead from firearms impacts children is layered and complex. In basic terms, children can be exposed to lead by occupying the same space as someone who handled a weapon that used lead bullets or lead primer.
Alongside my colleagues, Drs. Aaron Specht (Purdue University) and Gabrielle Hoover (Harvard Medical School), I published a paper examining the lead-related risks of firearm ownership in 2017 by measuring the number of active Class A firearm licenses in Massachusetts cities and towns and its association with child lead levels in those same communities.
The study used data collected from the Massachusetts Department of Criminal Justice Information Services, Department of Public Health, and Federal Census to inform the rates of active firearm licensure in a community, elevated pediatric blood lead levels, lead in water and paint, spatial proximity to firing ranges, and demographic features such as population size, occupation, sex, race, ethnicity, and socioeconomic status. There were 347 sub-counties with data on licensing and lead exposure included in the study.
We found that firearm licensure was significantly associated with pediatric blood lead levels, closely following lead paint in degree of risk. Licensure also had greater explanatory power than many other variables, including lead in paint, lead in water, and lead-related occupations (construction, forestry, fishing, hunting, mining, and agriculture). This means the presence of firearms in a community, formerly undocumented, could be the reason certain demographic factors are historically related to lead exposure (such as studies of occupation or socioeconomic status). Furthermore, the significant correlation between lead levels and firearm licensure was stronger than those associated with any other variable.
In the prevalence rate analysis, children living in the highest quartile of firearm ownership were 2.16 times more likely to have elevated blood lead levels even though they were less likely to be exposed to lead paint, which is traditionally seen as the most aggressive exposure mechanism for children.
As with any research, there were several limitations that could impact our interpretation. The study was of a single year only, and measurement of environmental toxicants is inherently difficult. Regardless, the findings are significant enough to warrant a closer look and cautious approach to gun use.
There are many societal fears related to firearms and, separately, lead poisoning. This is especially true for young children. Unfortunately, results from this preliminary study point towards an important link between the two. Children growing up in high gun-licensed communities are at more than double the risk of elevated lead levels compared to their peers in lower licensed communities. Importantly, this study was the first of its kind to both incorporate the novel use of firearm licenses as a direct measure of ownership and to examine child lead levels and firearm ownership on a community level.
My team has multiple plans for future studies. We are currently attempting to analyze this relationship over a decade, between the 2010 and 2020 censuses. These data may help identify cause-and-effect. If findings are corroborated in further research, we plan on implementing a prevention program in partnership with local universities. These future investigations hinge on the ability to identify funding sources, which historically has been and remains a challenge for firearms-related research.