Migraines may cause permanent changes in brain structure, though just how this affects patients over the long-term is unknown, according to research out Wednesday.

A meta-analysis performed on six population-based studies and 13 clinic-based studies was published in Neurology, a journal of the American Academy of Neurology.

The review found that people with migraines faced a higher risk of brain lesions, white matter abnormalities and altered brain volume than people without migraines.

"Traditionally, migraine has been considered a benign disorder without long-term consequences for the brain," said study author Messoud Ashina, with the University of Copenhagen in Denmark.

"Our review and meta-analysis study suggests that the disorder may permanently alter brain structure in multiple ways."

People who suffered migraine with aura -- in which patients experience advance warning signs such as sensitivity to light, dizziness or ringing in the ears -- had a 68 percent higher risk of lesions in the brain's white matter than people without migraines.

Migraine sufferers without aura had a 34 percent higher risk of brain lesions compared to people who do not get migraines.

Other abnormalities and brain volume changes were also more common in people who get migraines, the study found.

The World Health Organization says migraines often begin at puberty and can recur over a lifetime.

The painful headaches are "caused by the activation of a mechanism deep in the brain that leads to release of pain-producing inflammatory substances around the nerves and blood vessels of the head," said the WHO.

Around 10 percent of the population is believed to suffer from migraines. They are more common in women than men.

Migraines "can cause a substantial personal, occupational and social burden," Ashina said.

"We hope that through more study, we can clarify the association of brain structure changes to attack frequency and length of the disease. We also want to find out how these lesions may influence brain function."