Objective: The relation of hysterectomy and oophorectomy to change in bone mineral density (BMD) was examined in older women using and not using estrogen replacement therapy (ERT).
Methods: Women aged 60-80 years from the Rancho Bernardo Study attended clinic visits in 1988-1991 and 1992-1995 when hysterectomy and oophorectomy were ascertained, ERT use was validated and spine and hip BMD was assessed at both visits with DEXA. Women were either current ERT users or nonusers at both visits.
Results: Among these 447 women, average age was 71 (S.D.=9.0); average years postmenopause was 24.7 (S.D.=10.9). Overall, 122 had a hysterectomy with ovarian conservation and 91 had a hysterectomy with bilateral oophorectomy; 41% reported current ERT use for an average duration of 19.1 years (S.D.=10.8). Hysterectomized women were 2.3 times more likely to report ERT use than intact women (P<0.001). Comparisons adjusted for age, obesity, and age at menopause but not for ERT use showed hysterectomized women had less bone loss per year at the hip than intact women (P<0.05). However, this difference was explained by ERT; after adjustment for ERT, mean hip bone loss per year was -0.57% for intact women, -0.42% for hysterectomized women with ovarian conservation and -0.32% for bilaterally oophorectomized women (P's>0.10). There were no differences by hysterectomy or oophorectomy in bone loss at the spine or femoral neck. For all sites, women using ERT had higher BMD at both visits than nonusers (P's<0.001). Stratification by ERT showed that within users and nonusers, there were no differences in BMD or bone loss at any site by hysterectomy or oophorectomy.
Conclusions: There are no long term effects of hysterectomy and bilateral oophorectomy on bone loss. Women who use ERT have better BMD than nonusers.