Headaches among overweight youngsters also tend to be more frequent, said Andrew D. Hershey, M.D., Ph.D., director of the Headache Center, and a pediatric neurologist at Cincinnati Children's Hospital Medical Center, who presented the data.
He had more bad news: "Kids who are obese are also more likely to have increased disability from their headache." They miss more school and other activities.
But Hershey emphasized he did not find a cause-and-effect relationship. "Obesity doesn't cause you to have a migraine," he said.
His study, believed to be the first of its kind, echoes recent research on adult migraine sufferers.
Other researchers have reported that obese adults who get migraines also get hit harder -- in terms of frequency and severity -- than do thinner people. Exactly why is not known, experts say.
In the new study, Hershey and his colleagues evaluated 466 children, aged 3 to 18, who visited one of seven pediatric headache centers. Most of them -- 91.1 percent -- were diagnosed with migraine headaches; the other 8.9 percent had other types of headaches.
The Headache-Weight Connection
The researchers found that the young headache sufferers were 36 percent more likely to be overweight than children in the general population.
While 21.1 percent of the headache sufferers in the study were overweight, only 15.5 percent of children in the general population are.
Hershey and his colleagues calculated the children and teens' body mass index (BMI) percentile, a measure used to determine whether a child is overweight or at risk for being overweight.
A child with BMI in the 85th percentile to just below the 95th percentile for their age group and sex is termed "at risk of becoming overweight." Those at or above the 95th percentile are considered "overweight."
More Frequent, More Disabling
Hershey's team also asked the youngsters about headache frequency. "Up to 10 percent of kids 5 to 15 will have headaches -- one to two a month," Hershey said. "In our study, we found the average headache frequency was 11 times a month."
That wasn't a surprise, since the children were seeking help at a headache clinic. But Hershey also found that the heavier the child, the more likely he or she was to have frequent headaches.
The researchers asked how disabling the headaches were in terms of missed school days and other activities, and then gave each youngster a disability score.
Those overweight or at risk for being so had disability scores of 41.9 and 42.9 on a scale for which 30 to 50 is considered moderate. The healthy-weight children with headaches had a disability score of only 28.7.
"The question of whether the obesity directly leads to the headache is not solved," Hershey said. The association is complicated, but he suspects children with frequent headaches may be exercising less, and therefore gaining weight.
Mark Grossman, M.D., a pediatrician at Santa Monica-UCLA Medical Center in California, who was not involved in the study, said the weight-headache connection is worth further evaluation.
And he sees another potential association: "Very often obesity leads to poor sleep. Poor sleep, poor restfulness can increase episodes of headache."
Like Grown-up, Like Child?
Hershey's research was triggered by findings in adults, including a study by Richard Lipton, M.D., professor and vice chairman of neurology at the Albert Einstein College of Medicine in New York, and his colleagues.
The New York researchers evaluated more than 30,000 migraine sufferers. When they categorized them by body mass indexes as underweight, healthy weight, overweight, or obese, they found that as BMI increased to unhealthy levels, headache frequency and severity increased, too.
Lipton is not surprised that the study in children found the same. "It makes perfect sense," he says. "What we know in adults is that obesity probably doesn't predispose you to migraine, but if you are obese it makes your migraine more disabling."
Hershey and his colleagues are continuing to follow the children and teens they studied to evaluate the effect of weight loss on their headaches.
"If we treat their obesity, will their headache go away or improve?" That's the question the researchers hope to answer next.
Meanwhile, Hershey's advice to parents of overweight headache sufferers is to pay attention not only to their headache medication, but also to fostering healthy habits such as exercise, good nutrition, and proper sleep.
SOURCES:: Andrew Hershey, MD, pediatric neurologist and director of the Headache Center, Cincinnati Children's Hospital Medical Center, Ohio. Richard Lipton, MD, professor and vice chairman of neurology, Albert Einstein College of Medicine, New York City. 48th Annual Scientific Meeting of the American Headache Society, June 22-26, 2006, Los Angeles. News release from the American Headache Society.
By Kathleen Doheny
Reviewed by Louise Chang, M.D.
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