Five-year changes in bone density, and their relationship to plasma estradiol and pretreatment bone density, in an older population of postmenopausal women using long-term estradiol implants

Abstract

The aim of this study was to observe whether bone mineral density (BMD) improves over 5 years in older women using estradiol implants. A total of 18 women were selected who had commenced hormone replacement therapy (HRT) around the age of 60 years. The median age was 60.9 years (range 59.7–63.2 years). Each woman had a pretreatment bone scan and then received 6-monthly subcutaneous 50 mg estradiol implants. Twelve untreated women were also selected who had had bone scans at baseline and after 5 years. A comparison of the changes in BMD between treated and untreated women was made using the Wilcoxon rank-sum test. All changes at the hip and spine were statistically significant improvements from baseline in the estradiol-treated group. After 5 years of treatment, the estradiol-treated group had significantly improved bone mineral densities compared with the untreated group. At the spine, the plasma estradiol concentration is statistically significantly correlated with the 5-year increase in bone density (r = 0.717, p = 0.004). There was found to be an inverse relationship between the percentage increase in BMD over the 5-year period and initial bone density (r = −0.635, p < 0.005). Thus estrogen is seen to have the effect of improving bone density in older women over 5 years of treatment. The increase in vertebral bone density is most marked in those women with the highest plasma estradiol levels and the lowest pretreatment bone density.