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The prevalence of the prothrombin-gene mutation was higher in patients with cerebral-vein thrombosis(20 percent)than in healthy controls(3 percent;odd ratio,10.2;95 percent confidence interval,2.3 to 31.)and was similar to that in patients with deep-vein thrombosis(18 percent).Similar results were obtained for the mutation in the factor V gene.The use of oral contraceptives was more frequent among woman with cerebral-vein thrombosis(96 percent)than among controls(32 percent;odds ratio,22.1;95 percent confidence interval,5.9 to 84.2)and among those with deep-vein thrombosis(61 percent;odds ratio 4.4;95 percent confidence interval,1.1 to 17.8).For women who were taking oral contraceptives and who also had the prothrombin-gene mutation(seven patients with cerebral-vein thrombosis,but only one control)the odds ratio for cerebral-vein thrombosis rose to 149.3 (95 percent confident interval,31.0 to 711.).Mutations in the prothrombin gene and the factor V gene are associated with cerebral-vein thrombosis. The use of oral contraceptives is also strongly and independently associated with the disorder.The presence of both the prothrombin-gene mutation and oral contraceptive use raises the risk of cerebral vein thrombosis further. |
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