TORONTO - Doctors who see children who get chronic daily headaches frequently face the question "When will the headaches go away?"

The results of a study in Taiwan that tracked more than 100 young adolescents aged 12 to 14 for eight years provide some clues.

The study, published in the online issue of Neurology, the medical journal of the American Academy of Neurology, found that 60 per cent of the children no longer had chronic daily headaches after one year and three-quarters no longer had the headaches after two years.

And in 2008, eight years after the study began, 103 of the 122 children who were originally enrolled were interviewed by a neurologist with experience in headache studies.

By then, only 12 per cent still had chronic daily headaches, defined as 15 or more headache days per month where the average headache lasts at least four hours a day.

And compared with eight years earlier, two-thirds of the young people reported at least some improvement in headache intensity or frequency.

"Parents and children should be prepared for the possibility that while chronic daily headache may get better over time, headaches in general may never fully go away, but for most children the headaches are much less frequent when they become young adults," study author Dr. Shuu-Jiun Wang of the Taipei Veterans General Hospital said in a release.

Thirty-six people who were followed for eight years reported taking painkillers for their headaches, including seven who took prescribed drugs, 20 who took over-the-counter medication and nine who took both.

Dr. Kenneth Mack, a neurologist who co-wrote an accompanying editorial on the findings, says he often sees families who are anxious to find out if and when the headaches will disappear.

"I think most people will get better over time ... a lot of these patients will change from having daily headaches and grow up to be people who have occasional migraine headaches," said Mack, who practises at the Mayo Clinic Pediatric Center in Rochester, Minn.

About two per cent of girls and almost one per cent of boys will have chronic daily headaches, he said, and the numbers are higher for adults - four per cent of women, and two per cent of men.

"It is a challenge because I think the medical profession doesn't understand fully why patients do have daily headaches to begin with," he said, adding that he believes a lot of them have a personal or family history of migraines.

"But why do some people only get one or two migraines a month, and other people seem to have a headache every day? We don't know that," he noted.

"And on the flip side, why do people get better?"

Bad headaches can prevent children from going to school, playing sports and going outside and being with friends, he noted.

"And that's very challenging because when these children stop doing all those good things you get a lot of secondary effects. They feel sad because their health is in such a state, they become deconditioned and they become weak and dizzy when they try to do things," he said.

The Taiwan study will add to the information available for doctors and patients.

"The distressing part of this is there's still a percentage of patients who even after eight years will still have daily headaches, and so there's good news in this observation and there's some sad news in this observation as well," said Mack.