Effects of Long Term Hormone Therapy on Platelet Activation in Postmenopausal Women

Background : Platelet activation has been implicated in the pathogenesis of a number of diseases, which include atherosclerosis, coronary vascular disease, and cerebrovascular disease. There have been controversies with the influence of hormone therapy on platelet activation. The purpose of this study was to define the effect of long-term hormone therapy on platelet activation. Methods : We recruited a total of 162 postmenopausal women aged 55 and above among wihch eighty healthy postmenopausal women had received hormone therapy for more than 5 years and the remaining eighty- two healthy postmenopausal women with no hormone therapyapy. Baseline characteristics as well as the parameters related to platelet activation were compared between the two groups using T-test. After platelet activation was defined by the reference range, multivariated logistic regression analysis was performed determining the odds ratio of hormone therapy on platelet activation. Results : The MPC and PCDW were significantly lower in the HT group than the Non-HT group (P＜0.001), which suggests that platelets were more activated in the HT group more than in the non-HT group. Multiple logistic regression analysis showed that the odds ratio of the possibility of platelet activation in HT group was 19 times (P＜0.001). Conclusion : Long term hormone therapy increased platelet activation significantly, which may be a contributing factor of thromboembolism.ope