Women who have a blood marker for an autoimmune disease that mainly affects women under the age of fifty, have a 40-fold increased risk for stroke. This is the conclusion of researchers from the University Medical Center (UMC) Utrecht in a paper published in the journal Lancet Neurology in November 2009. The researchers recommend that women who have had a stroke should be screened for this blood marker. Anyone who is affected could then be treated more intensively in order to prevent a repetition.
The blood marker in question is for antiphospholipid syndrome (APS) an autoimmune disease that occurs mainly in young women. Patients with APS have had thrombosis and carry the so-called antiphospholipid antibodies in their blood. These antibodies bind to cell membranes and consequently influence processes such as blood clotting. Although the syndrome itself is rare, approximately one percent of people have antiphospholipid antibodies in their blood.
The study was conducted in 175 women following a stroke, 203 following a heart attack and 628 healthy women – all of whom were younger than fifty. In the study, the researchers analyzed a questionnaire on lifestyle. This enabled them to gain insight into the risk factors for thrombosis, such as smoking and taking a contraceptive pill. The presence of antiphospholipid antibodies was determined by a blood test.
The antibodies were found in 30 women who had had an ischemic stroke, 6 who had had a myocardial infarction (heart attack) and also in 4 healthy participants. From the results, it can be deduced that the presence of these antibodies increases the risk of stroke by more than 40-fold. And this risk is much higher if the women with these antibodies smoke or take the contraceptive pill. All in all, the risk is then increased by 200-fold.
Based on their findings, the researchers recommend that women who have had a stroke should be routinely tested for the presence of this autoimmune disease. If they test positively for the disease, there is a high risk that they will suffer a further stroke or heart attack at sometime in the future. To prevent this from happening, they can be given intensive preventive treatment with drugs that inhibit the formation of blood clots.
Professor Philip de Groot, from the Department of Clinical Chemistry and Hematology at UMC Utrecht who led this research says: “The presence of the antiphospholipid syndrome in young women who have had a stroke is not just a straightforward risk factor. It is the only risk factor than might lead to another treatment being chosen. And that is what makes our research special.”
Screening for the presence of APS in women under fifty who have not had a stroke is not considered useful because the absolute risk of stroke in these women is still very low – no more than 0.3 per 1,000 person years. This means that each year, 3 out of every 10,000 women will have a stroke.
The Lancet Neurology article has already been published in the online version of the journal.