Case-control study of risk of cerebral sinus thrombosis in oral contraceptive users and in [correction of who are] carriers of hereditary prothrombotic conditions. The Cerebral Venous Sinus Thrombosis Study Group.
OBJECTIVE
To investigate whether users of oral contraceptives and in [corrected] carriers of a hereditary prothrombotic condition (factor V Leiden mutation, protein C, S, or antithrombin deficiency) have an increased risk of cerebral sinus thrombosis.


METHODS
Comparison of a prospective series of cases of cerebral sinus thrombosis with population data.


METHODS
Neurological teaching hospitals from different regions in the Netherlands (cases) and a representative sample of the non-institutionalised Dutch population (controls).


METHODS
40 women aged 18-54 years with cerebral sinus thrombosis (cases) and 2248 women aged 18-49 years (controls).


METHODS
Current use of oral contraceptives at the time of the thrombosis (cases) or at the time of the questionnaire (controls). Prevalences of a hereditary prothrombotic condition in patients and in the population with odds ratios.


RESULTS
34 of 40 (85%) women with cerebral sinus thrombosis used oral contraceptives, versus 1007 of 2248 (45%) of the control women; the age adjusted odds ratio was 13 (95% confidence interval 5 to 37). Seven of 36 patients (19%) had a prothrombotic deficiency, versus 7% expected in the population; this corresponds to a threefold to fourfold increase in risk. In women who used oral contraceptives and also carried a prothrombotic defect, the odds ratio for cerebral sinus thrombosis was about 30 relative to women who had neither risk factor.


CONCLUSIONS
The use of oral contraceptives and being a carrier of a hereditary prothrombotic condition increase the risk of and interact in a multiplicative way in the development of cerebral sinus thrombosis.
de Bruijn
S F
SF
Department of Neurology, Academic Medical Centre, Amsterdam, Netherlands.
Stam
J
J
Koopman
M M
MM
Vandenbroucke
J P
JP
D000293:Adolescent; D000328:Adult; D001778:Blood Coagulation Disorders / Q000235:genetics; D016022:Case-Control Studies; D003276:Contraceptives, Oral / Q000009:adverse effects*; D005165:Factor V / Q000235:genetics*; D005260:Female; D006579:Heterozygote; D006801:Humans; D008875:Middle Aged; D009154:Mutation; D011446:Prospective Studies; D012307:Risk Factors; D012851:Sinus Thrombosis, Intracranial / Q000097:blood / Q000139:chemically induced* / Q000235:genetics
D003276:Contraceptives, Oral; C095381:factor V Leiden; D005165:Factor V