Effect of hormone therapy on the risk of bone fractures: a systematic review and meta-analysis of randomized controlled trials.
Topic: Hormone Therapy

The aim of this study was to investigate the association between hormone therapy (HT) use and the development of bone fractures.

PICO
Population: Postmenopausal women or individuals at risk of bone fractures
Intervention: Hormone therapy (HT) use
Comparison: No hormone therapy or placebo
Outcomes: Risk of bone fractures

Included studies:
title: A randomized controlled trial of four doses of transdermal estradiol for preventing postmenopausal bone loss. Transdermal Estradiol Investigator Group.
abstract: To determine the effects of four doses of a 7-day transdermal 17beta-estradiol (E2) delivery system, including 0.025 mg/day, on bone loss in postmenopausal women.
title: Estrogen replacement therapy I: a 10-year prospective study in the relationship to osteoporosis.
abstract: A 10-year, double-blind prospective study was undertaken to evaluate the effects of estrogen replacement therapy. The sample population consisted of 84 pairs of randomly chosen postmenopausal patients who were matched for age and diagnosis. One half of the patients received conjugated estrogens and cyclic progesterone, while the other half received placebo. Estrogen-treated patients whose therapy started within 3 years of menopause showed improvement or no increase in osteoporosis. Control patients demonstrate an increase in their osteoporosis.
title: Effects of oral and transdermal estrogen/progesterone regimens on blood coagulation and fibrinolysis in postmenopausal women. A randomized controlled trial.
abstract: Postmenopausal hormone replacement therapy is associated with a reduction in the incidence of coronary heart disease. However, inconclusive results have been reported with respect to the risk of stroke, and recent studies consistently showed an increased risk of venous thromboembolism in postmenopausal women using oral estrogen. There are surprisingly few interventional studies to assess the true effects of estrogen-progestin regimens on blood coagulation and fibrinolysis, and the impact of the route of estrogen administration on hemostasis has not been well documented. Therefore, we investigated the effects of oral and transdermal estradiol/progesterone replacement therapy on hemostatic variables. Forty-five healthy postmenopausal women, aged 45 to 64 years, were assigned randomly to one of the three following groups: cyclic oral or transdermal estradiol, both combined with progesterone, or no hormonal treatment. Hemostatic variables were assayed at baseline and after a 6-month period. Pairwise differences in the mean change between the three groups were compared using nonparametric tests. Oral but not transdermal estradiol regimen significantly increased the mean value of prothrombin activation peptide (F1 + 2) and decreased mean antithrombin activity compared with no treatment. Differences in fragment F1 + 2 levels between active treatments were significant. The oral estrogen group was associated with a significant decrease in both mean tissue-type plasminogen (t-PA) concentration and plasminogen activator inhibitor (PAI-1) activity and a significant rise in global fibrinolytic capacity (GFC) compared with the two other groups. A transdermal estrogen regimen had no significant effect on PAI-1, t-PA, and GFC levels. There were no significant changes in mean values of fibrinogen, factor VII, von Willebrand factor, protein C, fibrin D-dimer, and plasminogen between and within the three groups. We conclude that oral estrogen/progesterone replacement therapy may result in coagulation activation and increased fibrinolytic potential, whereas opposed transdermal estrogen appears without any substantial effects on hemostasis. Whereas these results may account for an increased risk of venous thromboembolism in users of oral postmenopausal estrogen, they emphasize the potential importance of the route of estrogen administration in prescribing hormone replacement therapy to postmenopausal women, especially to those at high risk of thrombotic disease.
title: Combination therapy with hormone replacement and alendronate for prevention of bone loss in elderly women: a randomized controlled trial.
abstract: Therapy with individual antiresorptive agents has been shown to be effective for prevention and treatment of postmenopausal osteoporosis, but whether combination antiresorptive therapy with hormones and bisphosphonates is safe or efficacious or how these agents compare in elderly women is unknown.
title: Effects of hormone replacement therapy on bone mineral density in postmenopausal women with primary hyperparathyroidism: four-year follow-up and comparison with healthy postmenopausal women.
abstract: Long-term treatment of patients with asymptomatic primary hyperparathyroidism remains controversial, but the presence of osteoporosis is regarded as an indication for parathyroidectomy. Hormone replacement therapy (HRT) is a possible alternative therapy in osteopenic postmenopausal women with the disorder, and results of short-term studies suggest a beneficial effect on bone mass comparable to that achieved by parathyroidectomy. Longer-term data are required to further assess the efficacy of this treatment in chronic stable primary hyperparathyroidism.
title: Alveolar and postcranial bone density in postmenopausal women receiving hormone/estrogen replacement therapy: a randomized, double-blind, placebo-controlled trial.
abstract: We conducted a 3-year, double-blind, randomized, placebo-controlled study to determine whether the positive effects of hormone/estrogen replacement therapy (H/ERT) on postcranial bone density are accompanied by similar positive effects on oral bone mass.
title: Hormone replacement therapy and the risk for first hip fracture. A prospective, population-based cohort study.
abstract: To determine the relative risk for sustaining a first hip fracture after hormone replacement therapy.
title: A randomized double-blind trial of the effects of hormone therapy on delayed verbal recall in older women.
abstract: We examined whether estradiol and norethindrone hormone therapy (HT) prevented decline in delayed verbal recall in older women with normal to mildly impaired memory functioning. This was a 2-year, randomized, double-blind, placebo-controlled trial of 142 women aged 61-87, randomly assigned to receive 1 mg 17-beta estradiol daily and 0.35 mg norethindrone 3 days/week or daily placebo for 2 years. The primary outcome was short-delay verbal recall of the California Verbal Learning Test (CVLT). To look for differences in response to HT by baseline short-delay recall, we examined the primary outcome in participants grouped according to whether their baseline scores were below average for the age group or greater than or equal to this score and according to whether they met criteria for Mild Cognitive Impairment (MCI) or not. 133 women completed 1 year of the trial and 128 completed 2 years. Prespecified covariates in all repeated measures analyses of covariance (RANCOVA) included age, education, APOE epsilon4, and prior HT use. RANCOVA showed no overall significant treatment effects at year 1 or year 2. After testing for an interaction, which was significant (p=0.02), we found that women in the HT group who scored at or above the average showed significantly less decline than the placebo group in short-delay verbal recall after 1 year, p=0.007 and 2 years, p=0.01. No treatment effects were found in women below the average in either year. When grouped according to whether the participant met criteria for MCI, the interaction between treatment group and MCI subgroup was not significant. These results suggest that benefits of estrogen exposure may be limited to those with average to above average scores on the delayed verbal recall. HT dose and formulation may have contributed to these beneficial outcomes. Replication is warranted before recommendations can be made in the clinical setting.
title: Main morbidities recorded in the women's international study of long duration oestrogen after menopause (WISDOM): a randomised controlled trial of hormone replacement therapy in postmenopausal women.
abstract: To assess the long term risks and benefits of hormone replacement therapy (combined hormone therapy versus placebo, and oestrogen alone versus combined hormone therapy).
title: Oestrogen therapy for prevention of reinfarction in postmenopausal women: a randomised placebo controlled trial.
abstract: Results of observational studies suggest that hormone replacement therapy (HRT) could reduce the risk of coronary heart disease (CHD), but those of randomised trials do not indicate a lower risk in women who use oestrogen plus progestagen. The aim of this study was to ascertain whether or not unopposed oestrogen reduces the risk of further cardiac events in postmenopausal women who survive a first myocardial infarction.
title: Differential effects of oral and transdermal estrogen/progesterone regimens on sensitivity to activated protein C among postmenopausal women: a randomized trial.
abstract: Activated protein C (APC) resistance not related to the factor V Leiden mutation is a risk factor for venous thrombosis. Oral estrogen replacement therapy (ERT) has been reported to induce APC resistance. Little is known about the effect of transdermal estrogen.
title: Estrogen replacement therapy and fractures in older women. Study of Osteoporotic Fractures Research Group.
abstract: To determine the relation between estrogen replacement therapy and fractures.
title: Oestrogen replacement therapy for prevention of osteoporosis after oophorectomy.
abstract: The value of oestrogen therapy in the prevention of osteoporosis after oophorectomy was assessed in 114 middle-aged women who participated in a double-blind controlled trial of mestranol in an average daily dose of 23 mug. The skeletal response to treatment was measured by a photon absorption technique. Where treatment was started within two months of operation subsequent bone mineral loss was prevented. Treatment started three years after oophorectomy caused a highly significant increase in bone mineral content. When treatment was delayed for six years mestranol failed to prevent subsequent bone mineral loss with age. These effects occurred independently of the associated humoral changes in calcium and phosphorus homoeostasis. Mestranol in this dosage appeared to be relatively safe, but it is too early to evaluate the long-term hazards of such therapy.
title: Osteoporosis and fractures in postmenopausal women using estrogen.
abstract: Previous studies demonstrate that postmenopausal women who use estrogen are somewhat protected from bone loss and fractures compared with nonusers, but the extent to which estrogen users remain at risk for osteoporosis and fractures is uncertain.
title: The effect of low-dose continuous estrogen and progesterone therapy with calcium and vitamin D on bone in elderly women. A randomized, controlled trial.
abstract: Hormone replacement therapy (HRT), the mainstay of osteoporosis prevention, is limited because of dose-related risks, side effects, and patient acceptance. The bone-sparing efficacy and tolerability of the lowest available doses of HRT have not been adequately studied in elderly women.
title: Results from the Estonian postmenopausal hormone therapy trial [ISRCTN35338757].
abstract: At present the Women's Health Initiative trial is the only reported randomised controlled trial studying the effects of hormone therapy among healthy postmenopausal women. The Women's Health Initiative reports have been criticized for lacking in generalisability, due to the characteristics of the trial population. We aimed to compare the health effects of oral continuous combined hormone therapy with a placebo and non-treatment among healthy Estonian women.
title: HRT and Vit D in prevention of non-vertebral fractures in postmenopausal women; a 5 year randomized trial.
abstract: We investigated the incidence of new non-vertebral fractures during HRT or low-dose vitamin (Vit) D3 supplementation in a 5-year prospective trial.
title: Estrogen replacement therapy for treatment of mild to moderate Alzheimer disease: a randomized controlled trial. Alzheimer's Disease Cooperative Study.
abstract: Several reports from small clinical trials have suggested that estrogen replacement therapy may be useful for the treatment of Alzheimer disease (AD) in women.
title: A combination of low doses of 17 beta-estradiol and norethisterone acetate prevents bone loss and normalizes bone turnover in postmenopausal women.
abstract: The effects of 17 beta-estradiol (E2) 1 mg combined with low doses of norethisterone acetate (NETA) on postmenopausal bone loss and turnover were investigated in a 2-year, randomized, double-masked, placebo-controlled trial. A total of 135 postmenopausal women with a lumbar spine bone mineral density (BMD) T-score between -2 and +2 were randomized to daily treatment with an oral tablet of either placebo, E2 1 mg/NETA 0.25 mg, or E2 1 mg/NETA 0.5 mg. Significant (p < 0.001) increases in BMD at the lumbar spine (L1-4) were observed with E2 1 mg/NETA 0.25 mg (5.2%) and E2 1 mg/NETA 0.5 mg (5.4%) compared with placebo (-0.9%). The total hip BMD increased significantly in the E2 1 mg/NETA 0.25 mg (3.1%) and E2 1 mg/NETA 0.5 mg groups (3.3%) compared with placebo. At the femoral trochanter, the increase in BMD in the E2 1 mg/NETA 0.5 mg group (6.3%) was significantly different from the placebo group (0.8%), while that in the E2 1 mg/NETA 0.25 mg group (3.3%) was not. No statistical differences were found between the active groups and placebo for the change in BMD at the femoral neck. Significant increases in BMD at the distal radius and total body were found for both E2 1 mg/NETA 0.25 mg (0.9% and 2.5%, respectively) and E2 1 mg/NETA 0.5 mg (2.1% and 3.0%, respectively) compared with placebo (-0.7% and 0.4%, respectively). At the end of the treatment, urinary pyridinoline type I collagen C-telopeptide had decreased by 65% and 60% in the E2 1 mg/NETA 0.25 mg and E2 1 mg/NETA 0.5 mg groups, respectively, while the mean serum concentrations of osteocalcin had decreased by 39% and 34%, bone-specific alkaline phosphatase by 32% and 29%, and C-terminal propeptide of type I collagen by 21% and 19% had decreased by 34-39%, 29-32%, and 19-21% in the E2 1 mg/NETA 0.25 mg and E2 1 mg/NETA 0.25 mg groups, respectively. In conclusion, combinations of E2 1 mg and NETA 0.25 or 0.5 mg prevent bone loss in postmenopausal women at the lumbar spine, hip, distal radius and total body, and normalize bone turnover.
title: Effects of hormone therapy on bone mineral density: results from the postmenopausal estrogen/progestin interventions (PEPI) trial. The Writing Group for the PEPI.
abstract: To assess the effects of hormone therapy on bone mineral density (BMD) in the spine and hip of postmenopausal women.
title: Effects of estrogen replacement on the progression of coronary-artery atherosclerosis.
abstract: Heart disease is a major cause of illness and death in women. To understand better the role of estrogen in the treatment and prevention of heart disease, more information is needed about its effects on coronary atherosclerosis and the extent to which concomitant progestin therapy may modify these effects.
title: Monofluorophosphate combined with hormone replacement therapy induces a synergistic effect on bone mass by dissociating bone formation and resorption in postmenopausal women: a randomized study.
abstract: Sodium fluoride stimulates bone formation and has been used to treat osteoporosis for decades despite debate about the antifracture efficacy. Hormone replacement therapy (HRT) results in only modest increases in bone mineral density (BMD). However, for women with low bone mass, the ideal therapy should not only inhibit bone resorption but simultaneously stimulate bone formation to increase bone mass above the fracture threshold. We thus performed a randomized, double-blind, placebo-controlled intervention study to prospectively investigate the effect of a low dose of fluoride, in combination with HRT, on BMD and biochemical markers of bone turnover. One hundred healthy postmenopausal women (60-70 yr old) were thus randomly assigned to: 1) HRT [transdermal 17beta-estradiol, releasing 50 microg/day; plus oral norethisterone acetate (NETA), 1 mg/day]; or 2) oral monofluorophosphate (MFP; equivalent to fluoride, 20 mg/day); or 3) HRT+MFP; or 4) placebo, for 96 weeks. All participants received a calcium supplement of 1000 mg/day. Sixty-eight women completed the study. We found a pronounced, linear increase in spinal BMD during treatment with HRT+MFP [11.8% (1.7% SEM)], which was significantly greater than the increase in the HRT group [4.0% (0.5% per yr); P < 0.05]. MFP produced a smaller increase [2.4% (0.6% per yr)], whereas there was no change in the placebo group [0.0% (0.5% SEM)]. Similar changes were found at the other skeletal sites (distal forearm, hip, and total body). Markers of bone formation showed a fall in the HRT group, which was significantly more pronounced than in the combined HRT+MFP group. A nonsignificant increase was found in the MFP group, whereas the placebo group showed a decrease caused by calcium treatment. The marker of bone resorption decreased significantly more in the HRT and the HRT+MFP groups than in the placebo group but tended to increase in the MFP group. In conclusion, this study shows, by use of biochemical markers of bone turnover, that bone resorption and formation may be dissociated, as a result of actions of two compounds with diverging effects on bone turnover. Furthermore, the synergistic effects of relatively low doses of the compounds suggested statistically and clinically significant increases in trabecular and probably also cortical bone. Adverse effects were relatively rare and mild.
title: Two to three years of hormone replacement treatment in healthy women have long-term preventive effects on bone mass and osteoporotic fractures: the PERF study.
abstract: Hormone replacement therapy (HRT) is often prescribed for a few years to suppress menopausal symptoms. Although its long-term use of HRT for the primary prevention of osteoporosis is not currently recommended, the long-term skeletal benefits of the limited therapy are of great interest. To determine whether administration of HRT for 2-3 years in the early postmenopausal years provides long-term benefits, such as prevention of bone loss and osteoporotic fractures, we studied a group of 347 healthy postmenopausal women with normal bone mass who had earlier completed one of four placebo-controlled HRT trials and who were reexamined 5, 11, or 15 years after stopping HRT. Of these women, 263 received either HRT or placebo for 2-3 years with no further bone-sparing treatment until follow-up, and the remaining 84 women reported either prolonged or current use of HRT at reexamination. Bone mineral density (BMD) at the spine (L1-L4) and bone mineral content (BMC) in the forearm were measured at baseline, the end of the trials, and follow-up. At follow-up, we assessed the radiological presence of vertebral fracture and collected information on the new incidence of nonvertebral fractures. Compared with that of the placebo-treated women, the BMD and BMC of HRT-treated women continued to show significantly higher values (>5%) even many years after stopping HRT. After stopping treatment, the rate of bone loss returned to normal postmenopausal rates. The preservation of bone mass in the HRT group was accompanied by a significantly reduced risk of all osteoporotic fractures as compared with the placebo group [OR = 0.48 (95% CI, 0.26-0.88)]. 'Fast losers' on placebo had more than a 4-fold higher risk of fractures than had the women on limited HRT with a normal rate of bone loss after withdrawal. In conclusion, limited HRT administered in the early postmenopausal years offers long-lasting benefits for the prevention of postmenopausal bone loss and osteoporotic fracture.
title: Activated protein C resistance among postmenopausal women using transdermal estrogens: importance of progestogen.
abstract: Although the route of estrogen administration is known to be an important determinant of the thrombotic risk among postmenopausal women using hormone therapy, recent data have shown that norpregnane derivatives but not micronized progesterone increase venous thromboembolism risk among transdermal estrogens users. However, the differential effects of progesterone and norpregnanes on hemostasis have not yet been investigated.
title: A four-year randomized controlled trial of hormone replacement and bisphosphonate, alone or in combination, in women with postmenopausal osteoporosis.
abstract: Hormone replacement therapy (HRT) with estrogen and treatment with bisphosphonates have been shown to increase bone mineral density (BMD) in postmenopausal women. This 4-year prospective randomized study was carried out to assess the effectiveness of the combined HRT plus etidronate on BMD in postmenopausal women with established osteoporosis.
title: Early response in biochemical markers predicts long-term response in bone mass during hormone replacement therapy in early postmenopausal women.
abstract: Based on data from 153 early postmenopausal women who completed a double-blind, randomized 3 year study of graded hormone replacement therapy (HRT) doses or placebo, we investigated the value of bone markers to predict prevention of bone loss. Absolute values of serum and urinary CrossLaps (S-CTX and U-CTX) after 2 weeks of treatment were significantly correlated to 3 year bone mass response (r = -0. 28/-0.35; p < 0.001). These associations were fully expressed at 6 months (r = -0.61/-0.64; p < 0.001). Receiver operating characteristic analyses revealed that the predictive capacity of one measurement of a resorption marker after 6 months' treatment performed similarly as assessment of hip bone mass over 3 years in predicting preservation of spinal bone mass over 3 years. Comparable results were obtained using percent change from baseline in resorption markers at both 6 and 12 months, whereas for formation markers percent change was superior to absolute value at 6 months but not at 12 months. Values of accuracy for S-CTX for a cutoff of 1881 pmol/L at 6 months were 85.2% (sensitivity), 74.3% (specificity), 90.5% (positive predictive value), and 63.4% (negative predictive value); U-CTX performed similarly, whereas the values for the formation markers were slightly lower. A cutoff for S-CTX of 1245 pmol/L eliminated false-positive individuals (those who had a decrease below the cutoff but lost bone). In the false-negative group, which was composed of individuals whose S-CTX did not decrease below the cutoff but had preserved bone mass, S-CTX was significantly associated with spinal bone mass response (r = -0. 41; p < 0.01), indicating these women had been treated with a dose that was not at its optimum for their individual bone turnover. For this cutoff, the values were 49.5% (sensitivity), 97.1% (specificity), 98% (positive predictive value), and 40% (negative predictive value). In conclusion, early bone marker measurements predict long-term preservation of bone mass during HRT. Resorption markers seem superior to formation markers, which reflects that the primary effect of HRT is on bone resorption. A strategy with two cutoff levels may optimize the use of bone markers to predict bone mass response. Whether resorption markers can be used to guide individualized treatment remains to be investigated.
title: Hormonal replacement therapy reduces forearm fracture incidence in recent postmenopausal women - results of the Danish Osteoporosis Prevention Study.
abstract: To study the fracture reducing potential of hormonal replacement therapy (HRT) in recent postmenopausal women in a primary preventive scenario.
title: Effects of hormone replacement therapy on clinical fractures and height loss: The Heart and Estrogen/Progestin Replacement Study (HERS).
abstract: To determine if estrogen plus progestin reduces the incidence of fractures or height loss in postmenopausal women with coronary disease.
title: Hormone replacement therapy and risk of hip fracture: population based case-control study. The Swedish Hip Fracture Study Group.
abstract: To determine the relative risk of hip fracture associated with postmenopausal hormone replacement therapy including the effect of duration and recency of treatment, the addition of progestins, route of administration, and dose.
title: Effectiveness of Alora estradiol matrix transdermal delivery system in improving lumbar bone mineral density in healthy, postmenopausal women.
abstract: To determine the lowest effective dose of an estradiol (E ) matrix-type transdermal delivery system (EMTDS; Alora) for preventing bone loss in postmenopausal women.
title: Low-dose esterified estrogen therapy: effects on bone, plasma estradiol concentrations, endometrium, and lipid levels. Estratab/Osteoporosis Study Group.
abstract: Prospective studies have shown that doses equivalent to conjugated equine estrogens of 0.625 mg/d or higher are needed to produce a significant increase in bone mineral density of the lumbar spine.
title: Effects of estrogen plus progestin on risk of fracture and bone mineral density: the Women's Health Initiative randomized trial.
abstract: In the Women's Health Initiative trial of estrogen-plus-progestin therapy, women assigned to active treatment had fewer fractures.
title: Effects on bone mass after eight years of hormonal replacement therapy.
abstract: The purpose of this randomised double-blind placebo-controlled study over two years followed by a six year open controlled extension phase was to investigate the effects of hormonal replacement therapy (HRT) both continuous combined HRT and sequential HRT) versus no treatment on lumbar spine bone mineral density (L-BMD) and distal forearm bone mineral content (F-BMC). Further, bone mineral density of the proximal femur, lateral spine, and distal forearm was studied after eight years.