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Seventy-three healthy, postmenopausal women, aged 45-54 years, were randomly assigned to one of three groups for 2 years of treatment: 17 beta-oestradiol 1.5 mg on days 1-12 and 17 beta-oestradiol 1.5 mg + desogestrel 150 micrograms on days 13-24 (E2/DG) or oestradiol valerate 2 mg on days 1-11 and oestradiol valerate 2 mg + medroxyprogesterone acetate 10 mg on days 12-21 (E2V/MPA) or placebo. Fifty-seven women (78%) completed the study. Bone mineral content of the distal regions of the forearms (measured by single photon absorptiometry, SPA) and bone mineral density of the spine (measured by dual energy X-ray absorptiometry, DXA) showed increases of 0.5-1% and 4-5%, respectively, in the hormone groups over 2 years. The placebo group exhibited a decrease in spinal bone density of 2% per year, and in the forearm of 2.5-3.5% per year. Biochemical estimates of bone turnover (serum alkaline phosphatase and fasting urinary calcium) decreased significantly to premenopausal levels in the hormone groups but remained unchanged in the placebo group. In both hormone groups total cholesterol decreased by about 9% (P less than 0.001), whereas low density lipoprotein cholesterol decreased by 16% in the E2/DG group and 20% in the E2V/MPA group (P less than 0.001). High density lipoprotein cholesterol showed only minor, insignificant changes in the hormone groups. The placebo group had virtually unchanged values. Climacteric symptoms, including hot flushes, were significantly reduced in both hormone groups. Bleeding occurred regularly in about 80% of the women.(ABSTRACT TRUNCATED AT 250 WORDS)

Two dual energy X-ray absorptiometric (DXA) instruments have recently become commercially available for local bone densitometry: the QDR-1000 (Hologic Inc.) and the DPX (Lunar Radiation Corp.). We report the precision, influence of femoral rotation, correlation and agreement of bone mineral measurements of the proximal femur by these two instruments. In vitro (femur phantom) short-term precision was 1.1%-3.5%, and the long-term precision was 1.2%-3.8%. In vivo (groups of 10 premenopausal and 10 post-menopausal women) short-term precision of duplicate measurements was 1.6%-4.7%, and long-term precision was 1.9%-5.5%. Overall, the precision for Ward's triangle was over 3% and that for the femoral neck and trochanter, 2%-3%. Rotation of a femur phantom produced a statistically significant change in the bone mineral density (BMD) of the femoral neck. Within a clinically relevant range of femoral rotation (20 degrees inward rotation +/- 5 degrees) the coefficient of variation (CV%) increased by a mean factor of 1.1-1.4. Although the correlation (r less than 0.9) between BMD measurements of the proximal femur by the DPX and QDR-1000 in 30 postmenopausal women was high, there was lack of agreement between the two instruments. We found no statistically significant differences between the right and left femur in 30 postmenopausal women. A bilateral femur scan took a mean total time of about 22 min. We conclude that with the introduction of DXA instruments, the precision of bone mineral measurements of the proximal femur has improved. However, for comparability between commercially available DXA instruments, it might be advantageous if units were standardized.

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