[Evaluation of the effect of premenopausal oophorectomy on bone mineral content]

The effects of premenopausal oophorectomy on bone mineral content (BMC) and serum parameters of bone metabolism, ie E2, PTH, Ca, P, ALP, BGP, 1-25(OH)2D3 were studied. The BMC of the spongiosum of L-3 vertebral body was calculated by means of computed tomography which was utilized in conjunction with a calibrated phantom containing a set of reference densities (CaCO3). The BMC tended to decrease markedly in the late 40s (r = -0.669, p less than 0.01) and a 38% decrease was found among the postmenopausal group (age 50-60) in comparison with the premenopausal group (age 40-49) (206.9 +/- 38.0 vs 128.5 +/- 32.7 mg/cm3, p less than 0.005). In cases of premenopausal bilateral oophorectomy (mean age 42.5) the BMC was found to decrease significantly about 2 years after the operation (150.0 +/- 25.2 mg/cm3, p less than 0.005), while no significant difference was found between the controls (mean age 43.5) and unilateral oophorectomized cases (mean age 40.3). Findings that indicated a decrease in E2, a significant increase in BGP and ALP, and a tendency for PTH to decrease were noted among bilateral oophorectomized cases and this may indicate accelerated osteogenesis. It was suggested that premenopausal bilateral oophorectomized cases are in danger of developing severe osteoporosis and are candidates for rigorous preventive treatment.