An estimated 200,000 high school students who are bullied bring weapons to school, according to research to be presented Sunday, May 4, at the Pediatric Academic Societies (PAS) annual meeting in Vancouver, British Columbia, Canada.

Researchers also found that youths who have been victimized in multiple ways are up to 31 times more likely to carry a weapon to school than those who have not been bullied.

"Victims of bullying who have been threatened, engaged in a fight, injured, or had property stolen or damaged are much more likely to carry a gun or knife to school," said senior investigator Andrew Adesman, MD, FAAP, chief of developmental and behavioral pediatrics at Steven & Alexandra Cohen Children's Medical Center of New York.

Dr. Adesman and principal investigator Lana Schapiro, MD, FAAP, analyzed data from the 2011 Youth Risk Behavior Surveillance System. The system includes a nationally representative survey of more than 15,000 U.S. high school students conducted by the Centers for Disease Control and Prevention (CDC). Students were asked if they had ever been bullied on school property in the past year and on how many days in the past month they carried a weapon on school grounds.

The researchers looked at whether any of the following risk factors increased the likelihood that victims would carry a weapon to school: not going to school due to feeling unsafe in school or on the way to school; had property stolen or damaged; had been threatened or injured with a weapon; and had been in a physical fight. They also looked at what occurred when students experienced multiple risk factors.

Results showed that 20 percent of high school students reported being victims of bullying. Those who were bullied were more likely to be in lower grades, females and white. They also were more likely to carry a weapon to school than kids who were not bullied (8.6 percent vs. 4.6 percent).

"Large numbers of high school students report having been victimized by bullies and admit to carrying a weapon to school. Greater efforts need to be expended on reducing bullying in all of its many forms," said Dr. Schapiro.

The researchers also found a dramatic increase in the likelihood that victims of bullying went to school with a weapon if they experienced multiple risk factors. Up to 28 percent of students experiencing one risk factor brought a weapon to school, while up to 62 percent of those experiencing three risk factors carried a weapon on campus.

"Tragedies like the Columbine High School massacre have alerted educators and the public to the grave potential for premeditated violence not just by bullies, but by their victims as well," said Dr. Adesman. "Our analysis of data collected by the CDC clearly identifies which victims of bullying are most likely to carry a gun or other weapon to school."

"With estimates of more than 200,000 victims of bullying carrying a weapon to high school, more effective prevention efforts and intervention strategies need to be identified," Dr. Schapiro added. "The greatest focus should not just be on bullies, but on the victims of bullies most likely to carry a weapon and potentially use deadly force if threatened."

Dr. Schapiro will present "Exponential, Not Additive, Increase in Risk of Weapons Carrying by Adolescents Who Themselves Are Frequent and Recurrent Victims of Bullying" on May 4, 2014. To view the study abstract, go to http://www.abstracts2view.com/pas/view.php?nu=PAS14L1_2725.3&terms=.