Oophorectomy and spine bone density: Evidence of a higher rate of bone loss in surgical compared with spontaneous menopause

To compare the influence of spontaneous and surgical menopause on bone loss, we measured with dual x-ray absorptiometry (DXA) the spinal bone mineral density (BMD) in 513 women recruited at the Menopause Clinic at Ferrara University Hospital. One hundred one women were premenopausal with regular menstrual cycles; 185 women were perimenopausal with irregular periods or with absence of menstruation for < 11 months; 160 women had spontaneous menopause with at least 12 months of amenorrhea; 67 women had a surgical menopause (hysterectomy with bilateral oophorectomy) prior to which they had regular menstruation. To minimize the age bias on BMD, all postmenopausal patients were selected to have the age range at menopause corresponding with the chronological age range (45-53 years) of premenopausal women used as reference. Moreover, to evaluate the influence of time since menopause on BMD, all postmenopausal women were stratified in five categories according to time lapsed since their last me...