Migraine Linked to Double Risk for Silent Stroke
Medscape Medical News
May 20, 2014

Adults with migraine have an increased risk for ischemic silent brain infarction relative to their migraine-free peers, a new study confirms.

"Migraine is a neurovascular condition of the brain, with a small increased risk of silent brain infarctions, a risk factor for clinical stroke," lead author Teshamae Monteith, MD, assistant professor of clinical neurology and chief of the Headache Division at the University of Miami Miller School of Medicine, Florida, told Medscape Medical News.

"While the risk may be small, migraine patients with vascular risk factors should be treated for stroke risk factor reduction, including healthy lifestyle behaviors that include regular exercise and plenty of fruits and vegetables according the AHA/ASA [American Heart Association/American Stroke Association] guidelines," she added.

The new findings, published online May 15 in Stroke, are from the ongoing Northern Manhattan Study (NOMAS), a collaborative effort of researchers at the University of Miami and Columbia University in New York.

Subclinical Infarction
For this report, the NOMAS investigators quantified subclinical brain infarctions and white matter hyperintensity volumes (WMHVs) in 546 men and women. Their mean age was 71 years, and 65% were Hispanic.

Compared with people without migraine, those with migraine (confirmed by International Classification of Headache Disorders-2 criteria) had a 2-fold increased odds of subclinical brain infarction (adjusted odds ratio [OR], 2.1; 95% confidence interval [CI], 1.0 - 4.2).

The association between migraine and silent brain infarction was independent of sociodemographic and cardiovascular factors, and was stronger in the subgroup of patients with migraine without aura (OR, 2.6; 95% CI, 1.3 - 5.5), the researchers note. "The presence of aura, visual changes that occur with migraine, was not important for the association as was seen in some other studies," Dr. Monteith noted.

Hypertension, a risk factor for stroke, was more common in patients with migraine, but the association between migraine and silent brain infarction was also seen in normotensive participants, the researchers say.

"Unexpectedly," there was no association between migraine status and WMHV. It's possible that group differences in WMHV were not detected because of the high burden of other cardiovascular risk factors in this racially diverse older cohort, the researchers write.

This study confirms the association between migraine and silent brain infarctions in an older, diverse, predominately Hispanic population, Dr. Monteith said. "Previous studies of silent brain infarctions and migraine were conducted in predominately white populations," she noted. "While these lesions have an ischemic stroke appearance, the exact etiology of lesions is unknown in patients with migraine."

"Ultimately," Dr. Monteith said, "a large migraine cohort study is in order to determine if treatment of migraine may reduce stroke risks."

Small Numbers
Alexander Mauskop, MD, neurologist and director and founder of the New York Headache Center, New York, reviewed the study for Medscape Medical News.

He noted that the study population included 64 white, 72 black, and 392 Hispanic participants. "While this is diverse, there are not enough whites or blacks to make any statistical conclusions, so the study is focused on Hispanics," he said.

Dr. Mauskop also noted that of the 546 participants, 56 had a silent brain infarct and of these 56, 15 had a history of migraines.

"These are very small numbers to make any definitive conclusions, particularly because almost all patients in the migraine group had hypertension (84 out of 87), while in those without migraine only 67 out of 298 had hypertension," he said. "Hypertension is one of the major risk factors for strokes."

"This is a very interesting study, but I would not make any sweeping conclusions about the results," Dr. Mauskop concluded.

Dr. Monteith and colleagues say larger prospective multiethnic studies are needed to "elucidate the potential for silent brain infarction accumulation as a biomarker for subclinical cerebrovascular disease in individuals with migraine."

The study was funded by a Diversity Supplement of the National Institute of Neurological Disorders and Stroke. The authors and Dr. Mauskop have disclosed no relevant financial relationships.

Stroke. Published online May 15, 2014. Abstract