Indicators of lifetime endogenous estrogen exposure and risk of venous thromboembolism

Abstract

Background: Lifetime estrogen exposure has been related to breast cancer risk, osteoporosis, and cardiovascular disease but data on venous thromboembolism VTE) risk are limited. Methods: Data from a hospital-based case-control study among 608 postmen opausal women (191 with a first episode of idiopathic VTE and 417 age-matched controls) were used to determine whether estrogen exposure, as assessed by age at menopause [classi.ed as early (≤ 45 years), normal (46-54 years) and late menopause (≥ 55 years)] and parity, was associated with the risk of VTE. Results: After adjustment for potential confounding variables, the risk of VTE was increased with each year's delay in the menopause [odds ratio (OR) = 1.06, 95% confidence interval (CI) = 1.02-1.10, P < 0.0075]. When compared with women with normal menopause used as a reference, the adjusted OR for VTE was 0.59 (95% CI = 0.36-0.97) and 2.53 (95% CI = 1.28-4.99) for women with early menopause and late menopause, respectively (P = 0.001). Adjusted OR for VTE was also higher for women with more than two children when compared with those with less than or equal to two children (1.56, 95% CI = 1.03-2.34, P = 0.03). The lowest risk of VTE was observed in women with early menopause and lower parity (adjusted OR = 0.60, 95% CI = 0.30-1.24), the highest risk was among women with late menopause who have had more than two children (adjusted show that the longer exposure to endogenous estrogen is associated with an increased VTE risk. © International Society on Thrombosis and Haemostasis.