Migraine Linked to MS in Women
Women with physician-diagnosed migraine appear to have an increased risk of developing multiple sclerosis (MS), researchers found.
Among female nurses, the rate of migraine was higher among those who were eventually diagnosed with multiple sclerosis than in the overall cohort (21.9% versus 15%), according to Ilya Kister, MD, of NYU Langone Medical Center.
After adjustment for potential confounders, a migraine at baseline was associated with 47% increased risk of MS (RR 1.47, 95% CI 1.15 to 1.88).
Kister is slated to report the findings at the American Academy of Neurology meeting in April.
“Our work suggests that migraine may be another risk factor for multiple sclerosis,” he said in an email, adding that it might also be a comorbid condition. In any case, he noted, a migraine should not be be construed as a harbinger of MS.
“While having a history of migraine diagnosis was linked to multiple sclerosis, women with migraine need to know that over 99% of them will never develop [the disease],” Kister said in a statement. “Thus, having migraine should definitely not be a reason to worry about getting multiple sclerosis.”
There have been hints of a connection between migraine and multiple sclerosis.
Kister’s study is “consistent with what we see in clinical practice,” Lily Jung, MD, a neurologist at Swedish Medical Center in Seattle, said in an email. “Both migraines and multiple sclerosis are conditions seen more commonly in women. It isn’t surprising that you see an overlap like this.”
There have been relatively few studies of the connection, Kister noted, and most were conducted in specialty clinics, where samples may overestimate the frequency of headache and other conditions in patients with multiple sclerosis.
So he and his colleagues evaluated data from the Nurses’ Health Study II, which comprised 116,678 female nurses who were followed biannually from 1989 to 2005.
During follow-up, 375 women were diagnosed with multiple sclerosis, and these women were more likely to have reported a diagnosis of migraine at baseline.
The association persisted after controlling for age, latitude of residence, Scandinavian ancestry, vitamin D levels, smoking status, and body mass index.
Commenting on the study, Gary Birnbaum, MD, a neurologist at the Minneapolis Clinic of Neurology, said in an interview that it is unlikely there would be an immunologic or pathologic connection between migraine and multiple sclerosis.
The most likely explanation for the association, if confirmed, would be a common genetic factor, said Birnbaum, a spokesman for the American Academy of Neurology.
“We know that there is a genetic predisposition for migraine and there is a genetic predisposition or susceptibility for multiple sclerosis, and perhaps there’s an overlap between those two particular conditions.”
Because migraine is so comon, Birnbaum said, that the study findings probably will not have an effect on the clinical management of patients with the headaches or with MS.
“We hope that our work serves as stimulus for closer study of the inter-relationship between migraine and multiple sclerosis,” Kister added.
“One outstanding question is whether migraine affects the course and symptomatology of [the disease],” which should be further explored in prospective, population-based studies, he said.
Primary source: American Academy of Neurology Meeting
Source reference:
Kister I “Increased risk of multiple sclerosis among women with migraine in the Nurses’ Health Study II” AAN Meeting 2010.