Number of years since menopause: spontaneous bone loss is dependent but response to hormone replacement therapy is independent

Quantitative analysis of efficacy and associated factors of calcium intake on bone mineral density in postmenopausal women

A model-based meta-analysis method was performed to quantitatively analyze the efficacy characteristics of calcium intake in BMD increase among postmenopausal women. We found that age and calcium intake dose were key factors affecting the efficiency and onset of BMD change, and daily 1200 mg calcium was suggested to be a beneficial dosage.

INTRODUCTION

This paper aims to quantify the efficacy of calcium intake in preventing bone mineral density (BMD) decrease among postmenopausal women and to investigate the factors that may affect the efficacy.

METHODS

Comprehensive literature search was conducted in PubMed and EMBASE from January 2016. Placebo-controlled or no-treatment controlled randomized trials focused on calcium intake for the management of osteoporosis in postmenopausal women were included. The clinical and demographic characteristics of participants and efficacy data, defined as the mean percentage change of spine BMD (L2-L4) at each observation time point compared with that of baseline, were extracted from the studies. Model-based meta-analysis (MBMA) was used to describe the time course of BMD change by calcium intake and identify the related factors.

RESULTS

This study includes 17 trials involving 2537 subjects. The results showed that a classic pharmacodynamic maximal effect (E _max) model could describe the time course of BMD change by calcium intake. Using this model, we found that age and calcium intake dose were key factors affecting the efficiency and onset of BMD change. A 60-year-old woman administered with 800 mg/day calcium can achieve a maximum BMD increasing rate of 2.38%, and the time to reach 50% of this maximum (known as onset time) was 9.44 months. An increase of 0.0817% per year was noted in the maximal effect value for women aged between 50 and 83 years. For calcium dose interval from 250 to 2000 mg/day, the onset time was expressed as 9.44 × (dose/800)^-1.33 months. Two-year calcium intake of 700, 1200, and 2000 mg/day resulted in a maximum efficacy of BMD of 68.0, 81.3, and 89.6%, respectively. This indicates that the final efficacy had already reached the plateau (>80% E _max) under the 1200-mg/day dose.

CONCLUSION

Calcium intake can effectively postpone the tendency of BMD decrease in postmenopausal women. An increased calcium dose contributes to the shortening of the onset time. Considering the drug-acting rate and safety into account, menopausal women can be administered with a rational dose of 1200 mg/day to reduce bone loss.

Postmenopausal hot flushes and bone mineral density: a longitudinal study

OBJECTIVE

To study the possible association between menopausal hot flushes and bone mineral density.

DESIGN

Observational study.

SETTING

University clinic.

POPULATION

Healthy women (n = 143) with or without hot flushes, 6-36 months postmenopausal after participating in a 6-month hormone therapy trial.

METHODS

The women prospectively recorded the number and severity of hot flushes for 2 weeks. Bone mineral density in lumbar and hip bones was measured with dual-energy X-ray absorptiometry at recruitment and reassessed in 114 women approximately 6.2 years later.

MAIN OUTCOME MEASURES

Hot flushes and bone mineral density.

RESULTS

At recruitment, hot flushes were absent in 22 women, mild in 32, moderate in 28, and severe in 61. Lumbar bone mineral densities in non-flushing women (1.130 ± 0.022 g/cm(2) ; mean ± SEM), and in those with mild (1.088 ± 0.024 g/cm(2) ), moderate (1.082 ± 0.030 g/cm(2) ) or severe (1.102 ± 0.019 g/cm(2) ) hot flushes did not differ, nor were there differences in hip bone mineral densities between the four study groups. During the follow-up, lumbar bone mineral density decreased by a mean of 0.4 ± 0.1% a year in women not using hormone therapy, and increased by 0.1 ± 0.2% a year in hormone therapy users (p = 0.019). The respective non-significant changes in left and right total hip bone mineral densities were - -0.6 ± 0.01 and -1.0 ± 0.1 for the non-users, and -0.4 ± 0.1 and -0.6 ± 0.2 for hormone therapy users. These changes in bone mineral density bore no relation to the hot flush status at baseline.

CONCLUSION

In recently menopausal women, hot flushes do not appear to determine bone mass density.

Profile of bazedoxifene/conjugated estrogens for the treatment of estrogen deficiency symptoms and osteoporosis in women at risk of fracture

Decreasing levels of estrogens during menopause are associated with reduced bone density and an increased risk of osteoporosis. Many women also experience bothersome vasomotor and vaginal symptoms during the menopausal transition. Results of systematic reviews and meta-analyses of randomized controlled trials have shown that both systemic estrogen therapy or hormone therapy (estrogen combined with a progestin) are useful to prevent bone loss, and they are the most effective treatment for such climacteric symptoms as hot flushes, sweating, vaginal dryness, and dyspareunia. Unfortunately, estrogen therapy and hormone therapy increase the risk of endometrial and breast cancer, respectively. The selective estrogen receptor modulators (SERMs) result in positive estrogenic effects on bone, with no negative effects on the endometrium and breast but do not provide relief from postmenopausal symptoms. The combination of a SERM with estrogen as a tissue selective estrogen complex (TSEC) is a new strategy for the prevention of bone loss and the treatment of climacteric symptoms. This combination is particularly interesting from a clinical point of view, taking into account that estrogen alone did not increase breast cancer risk by the Women’s Health Initiative. TSEC is hypothesized to provide the benefits of estrogen-alone therapy, with an improved tolerability profile because the SERM component can make possible the elimination of progestin. The objective of this review was to critically evaluate the evidence from the reports published to date on the use of bazedoxifene (a third-generation SERM) in combination with conjugated estrogens in postmenopausal women. The conclusion is that effectively, the combination of bazedoxifene and conjugated estrogens may be a promising alternative to hormone therapy for the prevention of osteoporosis and the treatment of postmenopausal symptoms in non-hysterectomized postmenopausal women.

Response to oral bisphosphonates in subgroups of younger and older postmenopausal women

BACKGROUND

Although the effects of bisphosphonates in bone are known for postmenopausal women, it is not known if younger postmenopausal women have a similar response. Furthermore, it is not known if the effects of alendronate and risedronate differ in postmenopausal women in regard to age, specifically in women at or younger than the mean age of natural menopause. Our aim was to examine the effects of two oral bisphosphonates in postmenopausal women by age.

METHODS

This was a post-hoc analysis of postmenopausal women <55 or > or =55 years old with low bone mineral density (BMD), randomized to once weekly alendronate 70 mg or risedronate 35 mg for 1 year with 1-year extensions in U.S. and International Fosamax Actonel Comparison Trials.

RESULTS

In both age subgroups of postmenopausal women, alendronate produced significantly greater mean BMD increases from baseline than risedronate at hip trochanter, lumbar spine, total hip, and femoral neck. Changes in BMD were not significantly different between younger and older alendronate-treated women, although treatment differences favoring alendronate were numerically greater for younger than older postmenopausal women at all sites. Significantly greater reductions in bone turnover markers also occurred with alendronate vs. risedronate in both subgroups. Tolerability was similar between treatments.

CONCLUSIONS

In this post-hoc subgroup analysis of older and younger postmenopausal women receiving alendronate or risedronate, larger treatment differences in BMD gain in younger compared with older women suggest that patient age may affect the relative efficacy of these antiresorptive drugs.

Alendronate sodium in the management of osteoporosis

Alendronate is one of the best and most extensively studied bisphosphonates in the treatment of osteoporosis. This review considers in detail the major pivotal study, the fracture intervention trial (FIT), upon which the use of alendronate is based and which was a landmark study in terms of design, size and clinical impact. The role of alendronate has subsequently been underscored by a range of studies extending the clinical indications for its use and consolidating the effect on reducing both vertebral and non-vertebral fracture risk. Although the emphasis of these studies has predominantly been on the management of postmenopausal osteoporosis, data is also available in primary prevention, men, and glucocorticoids-induced osteoporosis. Direct comparison between the different drugs used to treat osteoporosis with fracture end points are needed for patients and doctors to make informed choices, but the size of such studies are prohibitive. Clinical trials using surrogate markers such as bone mineral density and biochemical markers of bone turnover have been performed which provide some helpful information but the limitations of this approach need to be recognized.

Prevention and treatment of postmenopausal osteoporosis

Osteoporosis is a systemic disease characterized by low bone mass and microarchitectural deterioration of the skeleton leading to enhanced bone fragility and an increased risk of fracture. Prior to fracture, diagnosis is established by documenting low bone mass. In the first section of this article we review the clinical use of bone mass measurements and biochemical markers of bone remodeling in selecting patients most in need of preventive therapy at menopause. Women with high bone turnover lose bone at menopause more rapidly than those with normal bone turnover and are more likely to derive benefit from the several preventive therapies available. The second section addresses the available technologies used to diagnose osteoporosis and/or establish fragility fracture risk using noninvasive bone mass measurement and biochemical markers of bone remodeling separately or in combination. In the third section we review the several treatment options available for patients with osteoporosis, including alendronate (alendronic acid), risendronate (risedronic acid), calcitonin, teriparatide, and raloxifene, and the approaches to monitoring the therapeutic response. The final section deals with fall protection--an often forgotten aspect of management of the patient at risk for sustaining and osteoporotic fragility fracture.

Levonorgestrel and 17beta-estradiol given transdermally for the prevention of postmenopausal osteoporosis

AIM

To evaluate the efficacy and safety of a new transdermal continuous combined hormone replacement therapy (HRT) for the prevention of postmenopausal osteoporosis.

METHODS

212 osteopenic (lumbar spine and/or hip (femoral neck) bone mineral density (BMD) between -1.0 and -2.5 S.D. of the premenopausal mean value) postmenopausal women aged 45-65 years participated in a 2-year prospective study. Treatments were 45 microg 17beta-estradiol combined with 30 (n = 69) or 40 microg (n = 72) levonorgestrel daily or placebo (n = 71) given as a 7-day patch. All received a daily supplement of 500 mg calcium. BMD at lumbar spine (L2-L4), hip and total body, as well as blood and urinary biochemical markers of bone turnover (serum osteocalcin (sOC), serum bone-specific alkaline phosphatase (sBSAP), urinary calcium (uCa) and urinary CrossLaps (uCTX)) were measured regularly.

RESULTS

BMD at the lumbar spine, hip and total body increased by 8, 6 and 3% (P < 0.001), respectively, in the hormone groups versus placebo. The bone markers all decreased accordingly (sOC: 37%, sBSAP: 34% and uCTX: 65% from baseline (all P < 0.001)), except for uCa that did not change significantly. No significant dose-related effect of levonorgestrel was found. Vaginal bleeding/spotting decreased from 48 to 25% of the HRT-treated women during the study period. Skin tolerance was good in 84% of the women with no difference between the study groups. No incidences of endometrial hyperplasia, uterine or mammary cancer occurred.

CONCLUSION

The transdermal combination of 17beta-estradiol and levonorgestrel has a positive effect on BMD in an osteopenic postmenopausal population. Furthermore, a high safety profile was observed.

Skeletal health in postmenopausal survivors of early breast cancer

Estrogen plays an important role in the skeletal health of all women. Many therapies used in the treatment of breast cancer reduce estrogen levels and have the potential to affect bone negatively by increasing the risk of osteoporosis and associated bone fractures. The long-term effects of systemic endocrine therapy on bone, therefore, are an important consideration in the adjuvant setting. Tamoxifen has been shown to have a moderate protective effect on postmenopausal bone due to its partial estrogen agonist activity; however, its long-term use is potentially associated with negative side effects, such as an increased risk of thromboembolic disease and endometrial cancer. Newer agents, the third-generation aromatase inhibitors (AIs), anastrozole, letrozole and exemestane, for example, do not possess estrogen agonist effects and have improved breast cancer outcomes when compared to the standard 5 years of tamoxifen. However, patients treated with adjuvant AIs have been shown to have an increased incidence of osteoporosis and osteoporotic fractures. In order to select the optimal adjuvant therapy for each patient, it is important to assess the overall risk:benefit ratio for each endocrine strategy. All postmenopausal women should follow published guidelines to assess the risk of osteoporosis and, where appropriate, they should receive bone mineral density monitoring. Postmenopausal women with breast cancer who are at increased risk of osteoporotic fracture should be identified and managed with appropriate nonpharmacologic and pharmacologic measures.

Prevention of postmenopausal bone loss: six-year results from the Early Postmenopausal Intervention Cohort Study

We report the effect of continuous treatment with alendronate for 6 yr vs. placebo in the Early Postmenopausal Intervention Cohort study. A total of 1609 healthy, early postmenopausal women were recruited; we describe results for the 585 women who received continuous placebo or alendronate (2.5 or 5 mg) daily for 6 yr. Bone mineral density (BMD) was evaluated at the lumbar spine, hip, forearm, and total body at baseline and annually thereafter. Bone turnover markers were measured every 6 months from baseline to yr 2 and annually thereafter. Adverse experiences, including upper gastrointestinal events and fractures, were recorded throughout the study. Women receiving placebo experienced progressive decreases in BMD at all skeletal sites. Patients receiving alendronate experienced significant gains in spine and hip BMD that were maintained through yr 6. Significantly greater, dose-related decreases in bone turnover markers in the alendronate groups vs. placebo occurred within the first year and were sustained through yr 6. Women receiving alendronate had adverse experience incidences similar to those receiving placebo. Fractures occurred in 11.5, 10.3, and 8.9% of women taking placebo, 2.5 mg alendronate, or 5 mg alendronate daily, respectively. Therapy with alendronate is an effective and promising strategy for the prevention of postmenopausal osteoporosis.

Overview on the effects of progestins on bone

In view of the fact that fractures are the clinically relevant events, risk factors for fractures are discussed first. Bone mineral density (BMD) appears to be a much less important risk factor for the most severe hip fractures than the risk of falling. No results of experimental studies on hormones and fractures at advanced age are available. An overview of the effects of progestins on bone is given. Effects of progestins on bone have been studied by in vitro experiments using cell lines and by more relevant clinical observations. Prospective studies have been conducted following the use of progestins contained in oral contraceptives, alone or in combination with oestrogens; long-term contraception by injection of depot preparations; so-called "add-back" hormonal therapy attempting to reverse the adverse effects of gonadotropin releasing hormone agonists on bone and after different regimens of hormone replacement therapy (HRT) in postmenopausal women. From the data there are no indications that the various progestins, used in clinical practice, have either a bone-protective or an oestrogen antagonistic activity. Progestins do not add or subtract much of the protective action of oestrogens on the bones.