447 women aged between 60 and 80 of which up to 122 had undergone either hysterectomy and oophrectomy (removal of the ovaries) or only oophrectomy.
Some of the women in both the operative group and the control group were using HRT. The groups were compared and the results demonstrate that those women that had undergone surgery had a similar level of Bone Mineral Density to those who had not undergone surgery. However, for those that had undergone surgery and were using HRT, they recorded a slightly higher BMD level than their non-HRT counterparts. The researchers concluded that there are no long term effects of hysterectomy and bilateral oophorectomy on bone loss and that women who use ERT have better BMD than nonusers.
(Maturitas. 2004 Jan 20;47(1):61-9)