A new meta-analysis found that an increased risk for migraine is caused by both being underweight and obesity. The research team evaluated all studies available on migraine and body mass index (BMI).

Lee Peterlin, DO, of Johns Hopkins University School of Medicine, the study author and a member of the American Academy of Neurology noted that it is vital that doctors and people that suffer from migraine be aware of these risk factors, as being underweight and obesity are both potentially modifiable. She did however add that more research is required to determine whether the risk for migraine would be lowered by efforts to help people gain or lose weight.

The meta-analysis looked at 12 studies, which included 288,981 participants. The researchers defined underweight as people with a BMI of less than 18.5, and obesity as people with a BMI of 30 or higher. They compiled the results and adjusted for sex and age. The results showed that people with obesity were 27% more likely to have migraines than people of normal weight were and that underweight people had a 13% bigger risk than people of normal weight did.

Ischemic heart disease is a condition of recurring discomfort or chest pain because part of the heart does not receive enough blood. Peterlin noted that the link between ischemic heart disease and migraine was moderate and similar in size to the link between migraine and bipolar disorders. The team found that the same was true for the link between obesity and migraine.

Peterlin also explained that sex and age were important variables in the relationship between body mass index and migraine because the risk caused by obesity and the risk of migraine is different in men and women, and in older and younger people. Both the occurrence of migraine and obesity disease risk is more common in younger people and in women.

She also noted that there was not yet clarity as to how body composition affects migraine. Fatty tissue discharges numerous molecule types that might play a role in triggering or developing migraine. Other factors such as medications, changes in physical activity, or other conditions such as depression could also possibly play a role in the relationship between body composition and migraine.

The meta-analysis was limited in that for more than half of the studies, people self-reported their body mass index, while people self-reported that they had migraines for half of the studies.