AKIPRESS.COM - According to a new study, the physical consequences of bullying might be explained by an increase in low-grade inflammation throughout the body.

Kids who are bullied tend to be sick more often than their peers and may have stomach aches, sleep problems and headaches and lose their appetites, researchers write in the journal PNAS.

In the new study, bullied kids had higher inflammation levels as young adults than their uninvolved classmates.

“We’re pretty confident that this is a bullying effect,” said William Copeland, who led the study at Duke University School of Medicine in Durham, North Carolina.

Inflammation might explain the connection between bullying and physical health, Copeland told Reuters Health. An increase in inflammation could lead to health problems like heart disease down the line, he said.

The authors followed 1,420 kids from age nine to 21, interviewing the kids and their mothers along the way about bullying involvement and taking blood samples from the kids every year or two.

They measured the level of C-reactive protein, a marker often used to gauge body-wide inflammation levels, in the blood samples. The marker can be affected by any number of stressors or changes in the environment, like lack of sleep or psychological problems, Copeland said.

C-reactive protein levels went up for all kids as they got older, but kids who had been repeatedly bullied saw more of an increase in inflammation than a group that was not involved at all in bullying. The more often kids reported being bullied, the more the inflammation marker increased over time.

One of the “common denominators” in many ills like cancer and heart disease is inflammation, he told Reuters Health.

The study also found that kids who were bullies but were never bullied themselves had less of an increase in inflammation over time than the group of kids not involved in bullying in any way.

Kids with the highest levels of inflammation were the ones who had experienced bullying repeatedly over a long period of time, or in multiple settings, Copeland said.

Parents and caretakers should deal with the potential long-term effects of bullying only after stopping the bullying from taking place, he said.