The type and time of menopause as decisive factors for bone mass changes

Background Early menopause, whether it be natural or surgical, is one of th e established risk factors for osteoporosis. Surgical menopause, however, d iffers from natural menopause owing to the abrupt cessation of estrogen sec retion. This study attempts to investigate the influence of menopause type on bone mineral density (BMD) changes. Methods Four groups, each consisting of 30 women, were compared: early meno pause (EMP), surgical menopause (SUMP) and two groups of natural menopause. The two groups share a similar number of years since menopause (YSM) but h ave a different chronological age (NMPO), or share a similar age but differ ent YSM (NMPY) to the EMP and SUMP. BMD was measured by the DXA method at L 2-L4 vertebrae and proximal femur. Results Mean vertebral BMD of EMP was lower than that of SUMP (P<0.05) and of NMPY (P<0.001) women. Femoral neck BMD did not differ between SUMP and E MP women but both exhibited significantly lower BMD than either natural men opause groups. BMD of SUMP and vertebral BMD of NMPY women was inversely co rrelated to chronological age and to number of YSM. Pertaining to T-score v alues according to the osteoporotic range, NMPO, EMP and SUMP women being h omogeneous exhibited significantly lower values than NMPY in the vertebrae (F-ratio = 7.84, P < 0.001). Whereas, in the femoral neck and the trochante r major, EMP and SUMP categories presented significantly lower T-score valu es than the NMPO and NMPY (F = 3.61, P<0.01 and 2.8, P<0.05 respectively). Conclusion Women with early menopause exhibit lower vertebral BIC LD than w omen of similar age after either surgical or natural menopause. In women of similar age, surgical menopause results in lower vertebral and femoral nec k densities compared to natural menopause. Chronological age and the interv al after menopause negatively affects bone density in women with similar ag e whether in surgical or natural menopause.