4.2 Biologic plausibility
More than 50% of hysterectomy is accompanied by oophorectomy because oophorectomy is the only unambiguous method to prevent ovarian cancer.14, 24, 42, 43 It is well known that the risk of CVD in women is lower than that in men due to the presence of estrogen before menopause, but after entering menopause, the risk of CVD is unbiased in men and women.11, 44 The possible reason for this result is the decrease of estrogen level due to the oophorectomy.45 Considering the surgical menopause due to oophorectomy, the American College of Obstetrics and Gynecology suggests premenopausal women choose hysterectomy with ovarian preservation if no genetic risk of ovarian cancer.46And some studies showed that ovarian preservation is beneficial to cardiovascular and nerve system.47-50 While in our results, the statistical significance was shown when the ovaries are preserved. As we all know, no recognized endocrine factors that have direct influence on the cardiovascular system can be produced from uterus.13 This association may be interpreted as a decrease of ovarian blood flow due to hysterectomy, leading to premature ovarian failure.14, 45 And the decline of ovarian reserve function subsequently promotes the consumption of follicles and finally accelerates arteriosclerosis.51, 52 In addition, there are a series of studies to prove that hysterectomy with ovarian preservation can also reduce the endogenous hormones.51-53