People ages 20 to 55 who were obese – either by a measure of belly fat or using the standard body mass index based on a person's height and weight – were more likely to report migraines or other severe headaches, they said.

Thirty-seven per cent of women with abdominal obesity as determined by waist circumference reported experiencing such headaches, compared to 29 per cent of non-obese women.

For men, 20 per cent with abdominal obesity reported migraines against 16 per cent who did not have abdominal obesity.

The findings were based on data from 22,000 people in a large US government health survey.

"Now we need to look at, well, if people lose weight can we scientifically prove that it helps headaches," Dr Lee Peterlin of Drexel University College of Medicine in Philadelphia, one of the researchers, said in a telephone interview.

"We know that studies have shown that exercise and activity helps with mood. So it's not illogical to think that it may actually improve headache," said Peterlin, whose findings will be presented at an upcoming meeting of the American Academy of Neurology in Seattle.

Migraines are severe headaches that also may include nausea, vomiting and sensitivity to light and noise. They are more common in women and often run in families.

They affect about 30 million people in the United States, or 10 per cent of the population, according to the National Headache Foundation. These headaches occur most frequently between the ages of 20 and 45, the group said.

The study found that after age 55, the increased risk of migraines for obese people was no longer present.

The researchers sought to clarify the link between migraines and obesity after previous studies had produced conflicting findings.