According to new research migraine sufferers may be more at risk of developing deadly blood clots in their veins.
The researchers from Innsbruck Medical University in Austria say the condition, venous thrombosis or thromboembolism, occurs when blood clots form in a vein - this in turn can restrict the blood flow and cause swelling and pain.
Such clots when they are dislodged from the vein can travel to the heart and the lungs, and can be fatal.
The research team conducted a study involving 574 people in Italy age 55 and over, in order to determine whether a history or incidence of migraine was linked to venous thrombosis.
For the study the arteries in the necks and thighs of the participants were scanned using ultrasounds to check for atherosclerosis, or hardening of the arteries which is a major risk factor for stroke.
The researchers found that of the group, 111 people had migraine and 21 of those also had one or more instances of venous thrombosis (19%) - in comparison, 35 people without migraine had the condition (8%) and migraine sufferers were found to be no more likely to have atherosclerosis than study participants without migraines.
The researchers say it is unclear why migraine and venous thrombosis are linked, but they suggest that the blood of people with migraine may be more prone to clotting.
The researchers also say that people with migraine are not more likely to have hardening or narrowing of the arteries, which is contrary to a current theory.
Lead author Dr. Stefan Kiechl says the theory has been that if people with migraine are more likely to have strokes and other cardiovascular problems, that they would also have more severe and early atherosclerosis.
Dr. Kiechl says their study is the first to use high-resolution ultrasound to examine this theory, and while the findings need to be confirmed, the study provides very strong evidence that atherosclerosis is not driving this link - he says the association between migraine and blood clots is a new and exciting finding.
Research in the last decade has shown an increased risk for stroke among women and men with migraines, particularly those who experience migraine with aura which has also been linked to an increased risk for a genetic disorder associated with blood clots, known as the factor V Leiden mutation.
Far more women than men suffer from migraine and experts say the research may change the thinking about migraines and stroke and the venous thrombosis link is very interesting.
The study is published in the current issue of Neurology, the medical journal of the American Academy of Neurology.