Objective: To evaluate the associations of oral contraceptives (OC) exposure, angiotensin-converting enzyme (ACE) gene polymorphism and their joint actions with the risk of stroke in Chinese women.
Methods: A case-control study, based on a set cohort, was carried out. Incident cases of stroke identified between July 1 1997 and June 30 2009 were enrolled. One hospital control and healthy community control were matched on region and age (± 3 years). A total of 453 women with stroke and 919 controls were recruited. I/D gene polymorphism was detected by polymerase chain reaction (PCR) and amplification fragment length polymorphism (AFLP), A-240T polymorphism were detected by TagMan.
Results: (1) The risk of stroke gradually increased with the cumulative time of OC being used in women (P < 0.0001). Compared with non-users, the risk of stroke significantly increased among those with cumulative time of using OC longer than 20 years (adjusted OR was 2.07, with 95%CI as 1.30 - 3.29). (2) ID/DD genotype of I/D locus indicated significantly an increased risk of hemorrhagic stroke (adjusted OR, 2.37; 95%CI, 1.46 - 3.84). (3) Women with ID/DD genotype of I/D locus or with TA/TT genotype of A-240T locus and using OC could significantly increase the risk of hemorrhagic stroke (adjusted OR was 4.59; with 95%CI as 2.21 - 9.51 and OR was 2.50; with 95%CI as 1.42 - 4.38). (4) Data from multivariate analyses showed that both OC and ID/DD genotypes were important risk factors for hemorrhagic stroke.
Conclusion: ID/DD and TA/TT genotypes of ACE gene, OC and their joint action might increase the risk of stroke, especially on hemorrhagic stroke in Chinese women.