Headache specialists have noticed that "a lot of patients with migraine also have asthma," says senior researcher Richard Lipton, MD, director of the Montefiore Headache Center. But a relationship linking the risk of one to the other hadn't been backed up with research before.
Both disorders, he says, involve similar changes inside the body. In asthma, the airways narrow and restrict airflow, and there is inflammation of the airway linings. During migraines, there is inflammation along with narrowing and widening of blood vessels. Those clues suggest the two conditions could be related, Lipton says.
Link Apparent in Large Study
The researchers used data from a previous study that included an asthma questionnaire, scores participants gave for the severity of their asthma symptoms, and data on how often they got headaches and how long those lasted.
Of 4,446 participants who had fewer than 15 migraines a month (what doctors call "episodic migraines"), 746 (16.8%) had asthma and 3,700 (83.2%) did not. About a year later, 131 people (2.9%) started getting 15 or more migraines per month, or "chronic migraines."
Participants with asthma had twice the risk of going on to get chronic migraines compared to those without asthma. The researchers say that finding held up after they took into account the people's ages, body fat, gender, headache frequency, and migraine prevention-medication use. The risk appeared to rise as the number of asthma symptoms increased, but this was significant only in people with the most severe asthma.
"While we found that overall presence of asthma about doubles the risk, the group with the most severe respiratory symptoms was more than three times as likely to develop chronic migraine as people free of asthma," Lipton says.
The decision to use migraine-prevention medication in people with asthma who get episodic migraines is complicated, Lipton says.
Some doctors aren't sure whether they should prescribe the beta-blocker medication propranolol to prevent migraines in people with asthma, he says. Beta-blockers typically aren’t used for people with the breathing condition because of a concern they may trigger asthma attacks.
He also speculates that treating asthma with drugs that reduce inflammation may help keep migraines from becoming more frequent, if inflammation is the link.
The researchers say their study has some limitations: 90% of the participants were white, they gave info on their symptoms through questionnaires, and the study only covered 1 year.