(CNN) Homicide is a leading cause of death for children in the United States, a new study says, and the overall rate has increased an average of 4.3% each year for nearly a decade.
Black boys were killed more than any other group, and firearms were the most common weapon used in children's deaths, according to the study, published Monday in the journal JAMA Pediatrics.
From 1999 to 2020, 38,362 US children were homicide victims, the researchers found.
The overall homicide rate had an especially "precipitous" rise from 2019 to 2020, with rates increasing across several demographics, the study says. In that time period alone, the number of children who were killed in a homicide rose 27.7%.
The marked increase may be partly driven by the general trend in firearm-related homicides of children, which rose 47.7% between 2019 and 2020, the study says.
Overall homicide rates increased the most for boys, rising 16.1% between 2018 and 2020. There was a decline in homicides among girls between 1999 and 2020, however.
The rate of homicides in Black children increased 16.6% from 2018 to 2020. Black and Hispanic children have been victims of a steady increase in homicides since 2012 and 2014, respectively.
American Indian and Alaska Native children had a decrease in homicide rates between 1999 and 2020, but it was not statistically significant, the researchers said. However, in most years, they have had the second-highest rates of homicide among racial and ethnic groups. The researchers also said these numbers may also be underestimated, since the race of some victims may have been misidentified as Hispanic.
Homicide rates for Asian, Pacific Islander and White children have steadily declined since 1999, the study says.
Earlier studies have shown that the racial disparities may be attributed in part to racism and the system-based inequities of the neighborhoods many children live in, with high concentrations of poverty, few safe places to play and underfunded school systems.
These neighborhoods are also run by authority figures who -- due to unconscious bias -- dehumanize these children and perceive them as "less childlike and innocent" and "as more culpable for their actions," with "fewer childhood protections and benefit compared to their White peers," the new study says.
The homicide rate has also increased since 2011 in rural areas that have seen limited employment opportunities and challenges with poverty. It's a slower climb than in urban areas, but is a longer period of an upward trend, the study says.
The child homicide rate in the South has also been increasing since 2013, the study found.
The researchers also looked at deaths by age group. Children 10 or younger were most often killed by neglect or abuse, usually from parents or caregivers, particularly a father's or mother's companion.
Most of the victims who were 11 and older were killed in arguments, during a crime or by a friend or acquaintance, the researchers found.
Black boys ages 16 to 17 had a homicide rate that was 18 times higher than that of White boys and 4.6 times higher than in Hispanic boys.
The rates of homicides of infants and 1- to 5-year-olds have been steadily declining for the past two decades. The researchers suggest that decline coincides with medical reform and federal programs like the Maternal, Infant, and Early Childhood Home Visiting Program, which supports pregnant people and parents of young children in communities with higher risks and barriers to positive maternal and child health outcomes, as well as training programs that emphasize positive parenting skills.
Dr. Karen Sheehan, an attending physician in emergency medicine at Ann & Robert H. Lurie Children's Hospital of Chicago, agreed that there may be a connection between these programs and the decline in homicides in the youngest children.
"We've put a lot of resources in this country to help strengthen families, through home visiting programs and also through sometimes programs like child tax credits, and perhaps that is why we're seeing the decrease in those categories because of this investment that we have made," said Sheehan, who was not involved in the new research.
Sheehan and other doctors have been working to improve the health of children through their Chicago Youth Programs.
"If we wanted to improve their health, it was essential to get them out of poverty, and for most, education was the shortest route," she said.
The programs offer tutoring, health care and recreation. Research shows that these kinds of youth development programs are effective at improving children's financial stability, education and well-being. Similar programs can also prevent violence against kids.
"If we invest strategically and structurally, we can move the needle on violent death," Sheehan said.
The new study found that homicides among 6- to 10-year-olds have been increasing since 2014.
The researchers say that most violence intervention programs at school for this age group focus on talking about sexual abuse and peer violence like bullying, rather than parent-child violence, unless the child is showing specific behavioral problems. The authors suggest that programs that educate about intimate partner violence may be needed.
The study also suggested that reducing access to "lethal means" like guns could reduce deaths in kids 6 to 10.
Sheehan said the numbers for this age group stood out.
"I think people often forget about this age group. We think about the younger kids with child abuse and the older kids with firearm injury, but that 6- to 10-year-old group -- it's something that we need to get on our radar and be paying attention to."
For the study, the researchers used the National Vital Statistics System's Wonder mortality data, which uses death certificates for US residents and the National Violent Death Reporting System.
Although reliable, the records may miss some homicides. Infant deaths might also be misclassified or not reported. Additionally, the data comes from only 45 states, so it can't be completely generalizable to the entire country, and the numbers underestimate the true number of homicides of children in the US.
Dr. Elinore Kaufman, an assistant professor in the department of surgery at the Perelman School of Medicine at Penn, said the increases in homicides were not surprising, but "that doesn't mean they're not alarming."
"I think, as a society, we have to take a hard look at the systems that we have in place to protect children and to try to come to an understanding of why they're not working better for these young children," said Kaufman, who wrote an editorial published alongside the study.
The US needs a multisector response to reduce the number of homicides involving children, she said.
For the little ones who more often die from abuse or neglect, there need to be policy interventions that "create and support services for new parents and families," including things like paid family leave and other programs that have been shown to decrease community rates of child abuse.
For all children, reducing access to firearms has the potential to save lives, Kaufman said. She also believes there needs to be more research to better understand the association between social inequity and poverty in communities.
"Child homicides are preventable," the study says. "The decrease in homicide rates for some geographic and child demographic groups is encouraging; however, more can be done to protect all children."
A separate study published Monday in JAMA Pediatrics found that the rates of firearm injuries treated at children's hospitals in the US significantly increased during the first year of the Covid-19 pandemic and stayed elevated throughout 2021.
The researchers compared the number of firearm injuries treated at children's hospitals between April 2020 and December 2021 against those from April 2018 to December 2019. There were 1,815 firearm injuries in the earlier period and 2,759 during the pandemic, a 52% increase.
In each time period, a higher proportion of the victims were Black children who were covered by public insurance, and children up to 5. There were no other significant demographic differences among the victims.
"The unequal burden of injury mirrors the disproportionate implications of Covid-19 for minoritized communities; pandemic conditions exacerbated many structural inequities that contribute to health disparities," the study says.
Addressing structural racism, poverty, unsafe communities and other elements that contribute to violence like homicides will take effort, but Kaufman is confident that changes can bring an end to violence against children.
"These are big problems, and it will take all of us to solve them. But that means that all of us in all our sectors, whether it's health care, whether it's education, whether it's social services, and whether -- and I actually do believe this -- that the media has a huge role to play," she said. "I think all of us in our sectors have a role to play and have the opportunity to make a difference for these children and for our society as a whole."