Children who suffer from migraine headaches are 36 percent more likely to be overweight, according to a new U.S. study.

Researchers were not surprised by the findings, as previous studies have linked obesity to migraine headaches in adults as well.

"The numbers tell us that being overweight may contribute to kids having more headaches, most often migraines," Dr. Andrew D. Hershey, director of the Headache Center and a pediatric neurologist at Cincinnati Children's Hospital Medical Center, said in a prepared statement. "There are likely a number of causes, including poorer general health, body stress, lack of exercise and nutrition. It may not be that being overweight directly causes migraine, but that the reasons for being overweight cause these children to have worsening headaches."

Researchers evaluated 440 children between the ages of 3 to 18 who visited one of seven pediatric headache centers. Of the entire population, just over 91 percent were diagnosed with migraine headaches and close to 9 percent had other types of headaches. While 15.5 percent of U.S. children are considered overweight, more than 21 percent of headache-prone children in the study were overweight, the researchers said.

Severity of headaches was also examined and calculated on a scale where a score of between 30 and 50 signified moderate disability due to headache. Children who were overweight had an average score of 41.9, those at risk of being overweight a score of 42.9, and children of normal weight a score of 28.7.

Results of the study were to be presented at this week's annual meeting of the American Headache Society, in Los Angeles.

"Obesity is a state of chronic, low-degree systemic inflammation," study author Dr. Marcelo E. Bigal, director of research at the New England Center for Headache in Stamford, Conn., said in a prepared statement. "Most of the inflammatory markers that are elevated in obese people also play a role in the inflammation of blood vessels in the brain that occurs during migraine attacks. Being a pro-inflammatory state, obesity may increase the chances of migraine attacks in people who are biologically predisposed to suffer from migraines."