Smoking and oral contraceptives may increase risk of stroke for some young women
Dutch scientists have found that young women with lupus anticoagulant (LA) are at a far greater risk of stroke and heart attack than those without the antibody. The risk increases even further for these women if they are smokers and use oral contraceptives. Results from the study are published in the journal Lancet Neurology.
LA is a particular subtype of antibody related to antiphospholipid syndrome (APS), an autoimmune condition that mainly affects young women and causes bleeding and complications during pregnancy. According to the scientists, the syndrome is an acquired risk factor for arterial thrombosis, one of the most common causes of death in developed countries today. 'Although the incidence of arterial thrombosis in individuals younger than 50 years is low, the burden of disease in young people is large,' they write.
APS is usually diagnosed when antiphospholipid antibodies are tested after a young woman has suffered a thrombotic event, such as a heart attack or stroke. In their study, the scientists wanted to determine the extent of the risk for heart attack or stroke in women who have the condition.
The team from the University Medical Centre Utrecht and the Leiden University Medical Centre in the Netherlands used data from a large population-based case-control study called RATIO (Risk of Arterial Thrombosis in relation to Oral Contraceptives).
Over 1,000 women under the age of 50 were enrolled in the study, including healthy controls (628) and women who had had a stroke or heart attack (378) between 1990 and 2001. All women were asked to fill in a standard questionnaire to assess cardiovascular risk factors (including the use of oral contraceptives and smoking) and submitted blood samples to measure their antiphospholipid antibody profiles.
Based on their results, the scientists estimate that the prevalence of LA in women in the general population is 7 in every 1,000 (previous studies have suggested a higher figure). LA was found in 30 patients who had had a stroke, 6 patients who had had a heart attack, and 4 in the control group. Compared with healthy controls, the team concluded that LA increased the risk of stroke by 43 times and the risk of heart attack by 5 times. For women with LA who smoked or used oral contraceptives, the risk of stroke or heart attack was even greater, in some cases by more than 200 times.
The scientists write, 'Our results suggest that lupus anticoagulant is a major risk factor for arterial thrombotic events in young women, and the presence of other cardiovascular risk factors increases the risk even further.' They suggest that screening for LA in young women with ischaemic stroke is warranted.
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Document Reference: Urbanus, Rolf T, et al. (2009) Antiphospholipid antibodies and risk of myocardial infarction and ischaemic stroke in young women in the RATIO study: a case-control study. Lancet Neurology. DOI: 10.1016/S1474-4422(09)70239-X.
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