The Effect of 17β-Estradiol at Doses of 0.5, 1 and 2 mg Compared with Placebo on Early Postmenopausal Bone Loss in Hysterectomized Women

In a randomized double-masked placebo-controlled parallel-group trial 166 hysterectomized (± oophorectomy) perimenopausal and postmenopausal women aged 45–55 years with a follicle stimulating hormone level above 20 IU/l were treated with one daily dose of either 0.5 mg 17β-estradiol (E₂), 1 mg E₂, 2 mg E₂ or placebo for 2 years. Bone mineral density (BMD) and biochemical bone markers were determined. All three doses of E₂ were significantly better than placebo with respect to change in BMD at the lumbar spine (L1–L4) (p<0.0001 for all pairwise comparisons) and hip (femoral neck, trochanter, Ward’s triangle). The mean percentage change from baseline at the lumbar spine was −0.2%, 0.8% and 1.8% in the 0.5, 1 and 2 mg E₂ groups respectively compared with −3.5% in the placebo group. Both 1 and 2 mg E₂ were significantly better than placebo in increasing the BMD at the femoral neck (p<0.001), trochanter (p<0.01) and Ward’s triangle (p<0.0001), while 0.5 mg E₂ was significantly better than placebo at the femoral neck (p<0.001) and Ward’s triangle (p<0.0001). The overall difference in mean percentage change in BMD at the femoral neck versus placebo (−0.2%) was 3.8% for 0.5 mg, 4.0% for 1 mg and 3.9% for 2 mg E₂; the corresponding numbers for trochanter were −0.3%, 1.3%, 3.3% and 3.2%, respectively, and −2.2%, 2.9%, 2.9% and 4.0%, respectively, for Ward’s triangle. More than half the women who received placebo presented with a decrease in BMD at the hip. The percentage of women in the 0.5 mg E₂ group who maintained or increased BMD at the femoral neck, trochanter and Ward’s triangle was 69%, 56% and 44%, respectively. For 1 mg E₂ the numbers were 69%, 78% and 61% respectively, and for 2 mg E₂ were 59%, 68% and 59% respectively. Osteocalcin, serum pyridinium crosslinks, urinary pyridinium crosslinks and urinary hydroxyproline/creatinine decreased significantly (p<0.0001, p<0.05) in the 0.5, 1 and 2 mg E₂ groups compared with the placebo group after 6 and 24 months of treatment. Received: 28 May 2001 / Accepted: 11 October 2001