People who are underweight as well as those who are obese are more likely to suffer from migraine, according to a study.
Researchers looked at all 12 available studies on body mass index (BMI) and migraine, involving almost 300,000 people.
Obesity and being underweight are potentially modifiable risk factors for migraine
Dr Lee Peterlin, of Johns Hopkins University School of Medicine in the US,
When they compiled all of the results and adjusted for age and sex, they found that obese people were 27 per cent more likely to have migraine than people of normal weight.
People who were underweight, meanwhile, were 13 per cent more likely to have migraine than people of normal weight.
Study author Dr Lee Peterlin, of Johns Hopkins University School of Medicine in the US, said: "As obesity and being underweight are potentially modifiable risk factors for migraine, awareness of these risk factors is vital for both people with migraine and doctors.
"More research is needed to determine whether efforts to help people lose or gain weight could lower their risk for migraine."
Dr Peterlin said the risk between obesity and migraine was moderate and similar in size to the link between migraine and bipolar disorders and ischemic heart disease, a condition of recurring chest pain or discomfort when part of the heart doesn't receive enough blood.
She said age and sex were important variables in the relationship between body mass index and migraine.
Dr Peterlin said: "This makes sense, as the risk entailed by obesity and the risk of migraine is different in women and men and in younger and older people.
"Both obesity disease risk and the occurrence of migraine is more common in women and in younger people."
She added: "It's not clear how body composition could affect migraine. Adipose tissue, or fatty tissue, secretes a wide range of molecules that could play a role in developing or triggering migraine.
"It's also possible that other factors such as changes in physical activity, medications, or other conditions such as depression play a role in the relationship between migraine and body composition."
The findings were published in the journal Neurology.