Synergism between non-O blood group and oral estrogen in the risk of venous thromboembolism among postmenopausal women: The ESTHER study.

摘要

Numerous studies have reported an association between ABO blood type and venous thromboembolism (VTE). Most of them have found a higher prevalence of non-O blood type among VTE patients than control (1-6). Recent data have emphazised the synergism between non-O blood type and factor V Leiden mutation in VTE risk (7, 8). Other VTE risk factors, such as hormone therapy (HT) among postmenopausal women, may also modify the association between ABO blood type and VTE risk. Therefore, we investigated the association of VTE with ABO blood type and the potential effect modifiers for this association in a case-control study of VTE among postmenopausal women.We used the final data of the EStrogen and THromboEmbolismRisk (ESTHER) study performed in France between 1998 and 2006. Study design has been described (9, 10). Briefly, the population consisted of postmenopausal women aged 45 to 70 years with neither a personal history of VTE nor contra-indicationto hormone therapy (HT), nor predisposing factors for VTE. Cases had to have presented a first documented episode of idiopathic VTE. One to three controls were matched to each case for age, center and admission date. Data including information on ABO blood group were self-reported during a direct interview from the same standardized questionnaire. Prothrombotic mutations (factor V Leiden and G20210A prothrombin mutation) were determined by standard methods (11).