Supplemental Vitamin D and Incident Fractures in Midlife and Older Adults

BACKGROUND

Vitamin D supplements are widely recommended for bone health in the general population, but data on whether they prevent fractures have been inconsistent.

METHODS

In an ancillary study of the Vitamin D and Omega-3 Trial (VITAL), we tested whether supplemental vitamin D3 would result in a lower risk of fractures than placebo. VITAL was a two-by-two factorial, randomized, controlled trial that investigated whether supplemental vitamin D3 (2000 IU per day), n-3 fatty acids (1 g per day), or both would prevent cancer and cardiovascular disease in men 50 years of age or older and women 55 years of age or older in the United States. Participants were not recruited on the basis of vitamin D deficiency, low bone mass, or osteoporosis. Incident fractures were reported by participants on annual questionnaires and adjudicated by centralized medical-record review. The primary end points were incident total, nonvertebral, and hip fractures. Proportional-hazards models were used to estimate the treatment effect in intention-to-treat analyses.

RESULTS

Among 25,871 participants (50.6% women [13,085 of 25,871] and 20.2% Black [5106 of 25,304]), we confirmed 1991 incident fractures in 1551 participants over a median follow-up of 5.3 years. Supplemental vitamin D3, as compared with placebo, did not have a significant effect on total fractures (which occurred in 769 of 12,927 participants in the vitamin D group and in 782 of 12,944 participants in the placebo group; hazard ratio, 0.98; 95% confidence interval [CI], 0.89 to 1.08; P = 0.70), nonvertebral fractures (hazard ratio, 0.97; 95% CI, 0.87 to 1.07; P = 0.50), or hip fractures (hazard ratio, 1.01; 95% CI, 0.70 to 1.47; P = 0.96). There was no modification of the treatment effect according to baseline characteristics, including age, sex, race or ethnic group, body-mass index, or serum 25-hydroxyvitamin D levels. There were no substantial between-group differences in adverse events as assessed in the parent trial.

CONCLUSIONS

Vitamin D3 supplementation did not result in a significantly lower risk of fractures than placebo among generally healthy midlife and older adults who were not selected for vitamin D deficiency, low bone mass, or osteoporosis. (Funded by the National Institute of Arthritis and Musculoskeletal and Skin Diseases; VITAL ClinicalTrials.gov number, NCT01704859.).

In a Clinical Trial There Was No Effect of Vitamin D on Physical Performance in Either Black or White Women

Introduction: The effect of vitamin D supplementation on physical performance is controversial. Longitudinal cohort studies show very low levels of serum 25OHD (< 15- 20ng/ml) are associated with lower physical performance. There are few clinical trials of the effect of vitamin D on physical performance and results are mixed. Design: 163 white and 110 black independent living women entered a 12-month double blind randomized dose ranging study of daily vitamin D,400,800,1600,2400,3200,4,000,4800IU or placebo together with calcium supplement as needed for a total intake of 1200mg and mean diet vitamin D of 114 IU. Inclusion criteria: total serum 25OHD ≤ 20ng/ml (Diasorin RIA); no known disease or drugs affecting calcium or bone metabolism. Physical performance tests were performed at baseline and end as described in the Short physical performance battery (SPPB) that included Balance, Timed walk, Chair rising test. Additional tests included Timed up and Go, Grip strength and Balance (Biodex). Fall history was recorded at baseline and at 3-monthly visits. Serum 25OHD was measured by Diasorin RIA and LCMS, Free 25OHD was measured by Elisa (Future Diagnostics). Changes in physical performance and fallers were analyzed by dose groups and by quintiles of total and free serum 25OHD. This was a secondary analysis using Intent to treat strategy. Chi square and ANOVA determined association between dose, quintiles and tests. Results: Mean age 66.2 years (SD 7.3, range 57–87), mean BMI 30.3 kg/m2 (SD 5.9). Compliance, measured every 3 months, was 94% for vitamin D and 91% calcium. 147 White and 89 Black women completed study. There was significant better performance in physical performance in women < age 70 years compared to > age 70 years. Black women performed better with all tests except grip strength after adjustment for age and BMI. When the absolute change in test performance was examined according to serum total or free 25OHD quintiles there was no correlation between serum levels of 25OHD and change in any physical performance test except for an improvement in chair rising test in younger Black women. Conclusions: There is no significant effect of vitamin D on physical performance in either black or white women. In a previous analysis we found a significant U-shaped response in fall incidence in the serum 25OHD range 30-40ng/ml but in this analysis there is no correlation between physical performance of fallers versus non- fallers

Reference range for 24-h urine calcium, calcium/creatinine ratio, and correlations with calcium absorption and serum vitamin D metabolites in normal women

A study of 959 black and white women shows that the normal range for 24-h urine calcium excretion in white women is 30-300 mg and 10-285 mg in black women. Clinical laboratories use a normal range for 24-h urine calcium excretion of 100-300 mg; there is a need for them to update their age- and race-specific ranges.

INTRODUCTION

Recommendations for a normal range for 24-h urine calcium vary from a low of 50 mg to a high of 400 mg; most "laboratory normal ranges" based on older literature are incorrect. The objective of this analysis is to define a normal range for young women age 25-45 years and older women age 55-90 years, white and black, for 24-h urine calcium and calcium/creatinine ratio, and to examine the relationship between 24-h urine calcium, calcium absorption, and vitamin D metabolites.

METHODS

Data from 3 studies was collected on 959 normal black and white women, ages 25-87 years, for 24-h urine calcium, creatinine, calcium intake, serum 25-hydroxyvitamin D (25OHD),1,25 dihydroxyvitamin D (1,25(OH)₂D), and calcium absorption. Urine calcium and creatinine were measured on an auto-analyzer. Calcium absorption was measured by a single isotope method. Serum 25OHD and 1,25(OH)₂D were measured by competitive protein binding assay or radioimmunoassay. Because 24-h urine calcium did not fit a normal distribution, non-parametric methods were used to determine the 95% reference interval (RI) and 90% non-parametric confidence intervals (CI) calculated for groups.

RESULTS

The 95% reference intervals for 24-h urine calcium for women were as follows: black older 7-225 mg, black younger 8-285 mg; white older 37-275 mg, and white younger 23-287 mg. In older white women, 24-h urine calcium was significantly correlated with serum 1,25(OH)₂ D, r = 0.23, p < 0.001, calcium intake r = 0.12, p = 0.001, and calcium absorption r = 0.18, p = 0.003, but not serum 25OHD r = 0.07, p = 0.06.

CONCLUSIONS

The normal reference interval for 24-h urine calcium for black women is lower than white women. Twenty-four-hour urine calcium was correlated with serum 1,25(OH)₂ D calcium intake and calcium absorption, but not serum 25OHD. This range will be useful clinically for defining hypercalciuria and for following patients on vitamin D and calcium treatment.

Effect of vitamin D supplementation on total and free 25 hydroxyvitamin D and parathyroid hormone. An analysis of two randomized controlled trials

BACKGROUND

It is questionable as to whether total serum 25 hydroxyvitamin D (T25D) levels are lower in African Americans. We measured serum T25D, free 25hydroxyvitamin D (F25D) and serum parathyroid hormone (PTH) in African American and Caucasian women and studied the effect of vitamin D dosing to determine if differences by race or age occur.

METHODS

Healthy young and older Caucasian and African American women who were vitamin D insufficient were randomized in two clinical trials to escalating daily doses of vitamin D from 400 to 4800 IU and placebo for 12 months.

RESULTS

Baseline F25D and T25D were significantly lower in young but not older African American compared to Caucasian women. At baseline, the rate of change, or slope, in F25D with T25D was significantly greater in younger women than in older women, but difference in the rate of change in F25D with T25D is similar in African American and Caucasian women. After vitamin D supplementation, there was an increase in F25D, and the dose response was not significantly different by age or race. The ratio of F25D/T25D decreased in all groups once T25D exceeded ~60 nmol L^-1 . There was a progressive decrease in serum PTH with increasing vitamin D doses and the per cent change was similar for F25D and T25D.

CONCLUSION

Serum F25D and T25D are lower in younger African American women, and since dietary vitamin D is similar in the groups, it is likely that the cause of low serum 25OHD in African American women is due to reduced UV exposure and reduced skin production of vitamin D.

Effect of increasing doses of vitamin D on bone mineral density and serum N-terminal telopeptide in elderly women: a randomized controlled trial

BACKGROUND

There are few controlled studies of the effect of different doses of vitamin D3 on bone mineral density (BMD).

OBJECTIVES

We conducted a randomized placebo-controlled trial of increasing doses of vitamin D3 in 163 Caucasian and 31 African American women with serum 25-hydroxyvitamin D (25OHD) ≤50 nmol/L. This is an analysis of secondary outcome BMD to see if there is an association between percent change in BMD and dose of vitamin D3.

METHODS

Participants were randomly assigned to placebo, vitamin D3 400, 800, 1600, 2400, 3200, 4000, or 4800 IU/day; calcium supplements, average 600mg, were given to provide a total calcium intake of 1200 mg/d. The primary outcome was 12-month serum 25OHD level. Analysis methods include ANOVA and Pearson correlations.

RESULTS

The mean percent increase (±SD) in BMD at 12 months for all women was small; total body, 0.62% (± 2.72), femoral neck 0.59% (±3.58) and spine 0.43% (±2.80). There was no difference in BMD or serum N-telopeptide in response to vitamin D by dose or race. The increase in total body, spine and hip BMD in elderly women given vitamin D doses between 400 and 4800 IU daily and calcium supplementation is small, unrelated to dose or 12-month serum 25OHD, free 25OHD or 1,25(OH)2D. There was no evidence of a threshold change in BMD with increasing serum 25OHD or free 25OHD in this population.

CONCLUSIONS

We found no significant effect of daily vitamin D dose ranging from 400 to 4800 IU/day on BMD or serum N-terminal telopeptides in elderly women with initially low serum 25OHD.

Treatment of Endometriosis-Associated Pain with Elagolix, an Oral GnRH Antagonist

BACKGROUND

Endometriosis is a chronic, estrogen-dependent condition that causes dysmenorrhea and pelvic pain. Elagolix, an oral, nonpeptide, gonadotropin-releasing hormone (GnRH) antagonist, produced partial to nearly full estrogen suppression in previous studies.

METHODS

We performed two similar, double-blind, randomized, 6-month phase 3 trials (Elaris Endometriosis I and II [EM-I and EM-II]) to evaluate the effects of two doses of elagolix - 150 mg once daily (lower-dose group) and 200 mg twice daily (higher-dose group) - as compared with placebo in women with surgically diagnosed endometriosis and moderate or severe endometriosis-associated pain. The two primary efficacy end points were the proportion of women who had a clinical response with respect to dysmenorrhea and the proportion who had a clinical response with respect to nonmenstrual pelvic pain at 3 months. Each of these end points was measured as a clinically meaningful reduction in the pain score and a decreased or stable use of rescue analgesic agents, as recorded in a daily electronic diary.

RESULTS

A total of 872 women underwent randomization in Elaris EM-I and 817 in Elaris EM-II; of these women, 653 (74.9%) and 632 (77.4%), respectively, completed the intervention. At 3 months, a significantly greater proportion of women who received each elagolix dose met the clinical response criteria for the two primary end points than did those who received placebo. In Elaris EM-I, the percentage of women who had a clinical response with respect to dysmenorrhea was 46.4% in the lower-dose elagolix group and 75.8% in the higher-dose elagolix group, as compared with 19.6% in the placebo group; in Elaris EM-II, the corresponding percentages were 43.4% and 72.4%, as compared with 22.7% (P<0.001 for all comparisons). In Elaris EM-I, the percentage of women who had a clinical response with respect to nonmenstrual pelvic pain was 50.4% in the lower-dose elagolix group and 54.5% in the higher-dose elagolix group, as compared with 36.5% in the placebo group (P<0.001 for all comparisons); in Elaris EM-II, the corresponding percentages were 49.8% and 57.8%, as compared with 36.5% (P=0.003 and P<0.001, respectively). The responses with respect to dysmenorrhea and nonmenstrual pelvic pain were sustained at 6 months. Women who received elagolix had higher rates of hot flushes (mostly mild or moderate), higher levels of serum lipids, and greater decreases from baseline in bone mineral density than did those who received placebo; there were no adverse endometrial findings.

CONCLUSIONS

Both higher and lower doses of elagolix were effective in improving dysmenorrhea and nonmenstrual pelvic pain during a 6-month period in women with endometriosis-associated pain. The two doses of elagolix were associated with hypoestrogenic adverse effects. (Funded by AbbVie; Elaris EM-I and EM-II ClinicalTrials.gov numbers, NCT01620528 and NCT01931670 .).

Robust Zero-Field Skyrmion Formation in FeGe Epitaxial Thin Films

B20 phase magnetic materials have been of significant interest because they enable magnetic Skyrmions. One major effort in this emerging field is the stabilization of Skyrmions at room temperature and zero magnetic field. We grow phase-pure, high crystalline quality FeGe epitaxial films on Si(111). Hall effect measurements reveal a strong topological Hall effect after subtracting the ordinary and anomalous Hall effects, demonstrating the formation of high density Skyrmions in FeGe films between 5 and 275 K. In particular, a substantial topological Hall effect was observed at a zero magnetic field, showing a robust Skyrmion phase without the need of an external magnetic field.

Epitaxial growth of iridate pyrochlore Nd2Ir2O7 films

Epitaxial films of the pyrochlore Nd₂Ir₂O₇ have been grown on (111)-oriented yttria-stabilized zirconia (YSZ) substrates by off-axis sputtering followed by post-growth annealing. X-ray diffraction (XRD) results demonstrate phase-pure epitaxial growth of the pyrochlore films on YSZ. Scanning transmission electron microscopy (STEM) investigation of an Nd₂Ir₂O₇ film with a short post-annealing provides insight into the mechanism for crystallization of Nd₂Ir₂O₇ during the post-annealing process. STEM images reveal clear pyrochlore ordering of Nd and Ir in the films. The epitaxial relationship between the YSZ and Nd₂Ir₂O₇ is observed clearly while some interfacial regions show a thin region with polycrystalline Ir nanocrystals.

Treatment with denosumab reduces secondary fracture risk in women with postmenopausal osteoporosis

OBJECTIVES

A history of prior fracture is one of the strongest predictors of a future fragility fracture. In FREEDOM, denosumab significantly reduced the risk of new vertebral, non-vertebral, and hip fractures. We carried out a post-hoc analysis of FREEDOM to characterize the efficacy of denosumab in preventing secondary fragility fractures in subjects with a prior fracture.

METHODS

A total of 7808 women aged 60-90 years with a bone mineral density T-score of less than - 2.5 but not less than - 4.0 at either the lumbar spine or total hip were randomized to subcutaneous denosumab 60 mg or placebo every 6 months for 36 months. The anti-fracture efficacy of denosumab was analyzed by prior fracture status, to assess secondary fragility fracture, and by subject age, prior fracture site and history of prior osteoporosis medication use.

RESULTS

A prior fragility fracture was reported for 45% of the overall study population. Compared with placebo, denosumab significantly reduced the risk of a secondary fragility fracture by 39% (incidence, 17.3% vs. 10.5%; p < 0.0001). Similar results were observed regardless of age or prior fracture site. In the overall population, denosumab significantly reduced the risk of a fragility fracture by 40% (13.3% vs. 8.0%; p < 0.0001), with similar results observed regardless of history of prior osteoporotic medication use.

CONCLUSIONS

Denosumab reduced the risk of fragility fractures to a similar degree in all risk subgroups examined, including those with prior fragility fractures. Identifying and treating high-risk individuals could help to close the current care gap in secondary fracture prevention.

The role of soy isoflavones in menopausal health: report of The North American Menopause Society/Wulf H. Utian Translational Science Symposium in Chicago, IL (October 2010)

OBJECTIVES

If and to what extent soy protein, soy isoflavones, and their metabolites, including S(--)-equol, have beneficial effects on women's health is currently unclear. The North American Menopause Society (NAMS)/Utian Translational Science Symposium on Soy and Soy Isoflavones convened October 9-10, 2010, to clarify basic and clinical research findings as they relate to the risk and benefits of soy products for peri- and postmenopausal women.

METHODS

A working group of faculty and panelists composed of clinical and research experts in the fields of women's health and botanicals met during a 2-day translational symposium to cover the latest evidence-based science on isoflavones as they affect menopausal symptoms, breast and endometrial cancer, atherosclerosis, bone loss, and cognition. Full descriptions of the bioavailability and pharmacokinetics of isoflavones were also presented. Subspecialty groups then broke off with the goal of translating the information into a report for general medical practice and identifying further research areas. All faculty and panelists reviewed the final report, which was then approved by the NAMS Board of Trustees.

RESULTS

From the hundreds of studies reviewed in this report, there are mixed results of the effects on midlife women. Soy-based isoflavones are modestly effective in relieving menopausal symptoms; supplements providing higher proportions of genistein or increased in S(--)-equol may provide more benefits. Soy food consumption is associated with lower risk of breast and endometrial cancer in observational studies. The efficacy of isoflavones on bone has not been proven, and the clinical picture of whether soy has cardiovascular benefits is still evolving. Preliminary findings on cognitive benefit from isoflavone therapy support a "critical window" hypothesis wherein younger postmenopausal women derive more than older women.

CONCLUSIONS

Several areas for further research have been identified on soy and midlife women. More clinical studies are needed that compare outcomes among women whose intestinal bacteria have the ability to convert daidzein to equol (equol producers) with those that lack that ability (equol nonproducers) in order to determine if equol producers derive greater benefits from soy supplementation. Larger studies are needed in younger postmenopausal women, and more research is needed to understand the modes of use of soy isoflavone supplements in women. The interrelations of other dietary components on soy isoflavones consumed as a part of diet or by supplement on equol production also require further study, as do potential interactions with prescription and over-the-counter medications. And finally, greater standardization and documentation of clinical trial data of soy are needed.

Treatment with denosumab reduces the incidence of new vertebral and hip fractures in postmenopausal women at high risk

CONTEXT

The FREEDOM (Fracture REduction Evaluation of Denosumab in Osteoporosis every 6 Months) trial showed denosumab significantly reduced the risk of fractures in postmenopausal women with osteoporosis.

OBJECTIVE

We evaluated the effect of denosumab on the incidence of new vertebral and hip fractures in subgroups of women at higher risk for these fractures.

DESIGN

FREEDOM was a 3-yr, randomized, double-blind, placebo-controlled, phase 3 trial.

PARTICIPANTS AND SETTING

Postmenopausal women (N = 7808) with osteoporosis were enrolled at 213 study sites worldwide.

INTERVENTIONS

Subjects received s.c. denosumab (60 mg) or placebo every 6 months and daily supplements of calcium (≥1000 mg) and vitamin D (≥400 IU).

MAIN OUTCOME MEASURES

This post hoc analysis evaluated fracture incidence in women with known risk factors for fractures including multiple and/or moderate or severe prevalent vertebral fractures, aged 75 yr or older, and/or femoral neck bone mineral density T-score of -2.5 or less.

RESULTS

Compared with placebo, denosumab significantly reduced the risk of new vertebral fractures in women with multiple and/or severe prevalent vertebral fractures (16.6% placebo vs. 7.5% denosumab; P < 0.001). Similarly, denosumab significantly reduced the risk of hip fractures in subjects aged 75 yr or older (2.3% placebo vs. 0.9% denosumab; P < 0.01) or with a baseline femoral neck bone mineral density T-score of -2.5 or less (2.8% placebo vs. 1.4% denosumab; P = 0.02). These risk reductions in higher-risk individuals were consistent with those seen in patients at lower risk of fracture.

CONCLUSIONS

Denosumab reduced the incidence of new vertebral and hip fractures in postmenopausal women with osteoporosis at higher risk for fracture. These results highlight the consistent antifracture efficacy of denosumab in patients with varying degrees of fracture risk.

The vitamin D analogue 2MD increases bone turnover but not BMD in postmenopausal women with osteopenia: results of a 1-year phase 2 double-blind, placebo-controlled, randomized clinical trial

Most osteoporosis drugs act by inhibiting bone resorption. A need exists for osteoporosis therapies that stimulate new bone formation. 2-Methylene-19-nor-(20S)-1α,25-dihydroxyvitamin D(3) (2MD) is a vitamin D analogue that potently stimulates bone formation activity in vitro and in the ovariectomized rat model. In this randomized, double-blind, placebo-controlled study of osteopenic women, the effect of daily oral treatment with 2MD on bone mineral density (BMD), serum markers of bone turnover, and safety were assessed over 1 year. Volunteers were randomly assigned to three treatment groups: placebo (n = 50), 220 ng of 2MD (n = 54), and 440 ng of 2MD (n = 53). In general, 2MD was well tolerated. Although 2MD caused a marked increase in markers of bone formation, it did not significantly increase BMD. Since 2MD also shows marked activity on bone resorption (as revealed by dose-dependent increases in serum C-telopeptide cross-links of type I collagen in this study), 2MD likely stimulated both bone formation and bone resorption, thereby increasing bone remodeling.

Relationship between vitamin D, parathyroid hormone, and bone health

CONTEXT

There is a controversy regarding the definition of vitamin D insufficiency as it relates to bone health.

OBJECTIVE

The objective of the study was to examine the evidence for a threshold value of serum 25-hydroxyvitamin D (25OHD) that defines vitamin D insufficiency as it relates to bone health.

DESIGN AND PARTICIPANTS

This was a cross-sectional analysis of baseline data in 488 elderly Caucasian women, mean age 71 yr, combined with a literature review of 70 studies on the relationship of serum PTH to serum 25OHD.

SETTING

The study was conducted in independent-living women in the midwest United States.

MAIN OUTCOME MEASURE

The relationship between serum 25OHD, serum PTH, and serum osteocalcin and 24-h urine N-telopeptides was evaluated.

RESULTS

Serum PTH was inversely correlated with serum 25OHD (r = -0.256, P < 0.0005), but no threshold as defined by suppression of serum PTH was found within the serum 25OHD range 6-60 ng/ml (15-150 nmol/liter). However, in contrast, there was a threshold for bone markers, serum osteocalcin and urine N-telopeptides, that increased only below a serum 25OHD of approximately 18 ng/ml (45 nmol/liter). Calcium absorption was not correlated with serum PTH and serum 25OHD, and no threshold was found. A literature review of 70 studies generally showed a threshold for serum PTH with increasing serum 25OHD, but there was no consistency in the threshold level of serum 25OHD that varied from 10 to 50 ng/ml (25-125 nmol/liter).

CONCLUSIONS

Vitamin D insufficiency should be defined as serum 25OHD less than 20 ng/ml (50 nmol/liter) as it relates to bone.

Fall predictors in the community dwelling elderly: a cross sectional and prospective cohort study

OBJECTIVES

To ascertain the risk factors for falls, stumbles and recurrent falls in a cohort of elderly people with mean age of 76.7-/+6.1 years.

METHODS

137 community dwelling elderly living independently or in assisted living institutions participated in the study. Each subject was assessed by history, physical examination and physical performance tests at the beginning and end of study. Falls and stumbles were recorded in a falls dairy for 1 year.

RESULTS

Significant predictors of being a faller were a history of falls at baseline (Odds Ratio (OR) = 3.85, 95% Confidence Interval (CI) = 1.56 - 9.50), depression (OR = 1.19, 95% CI = 1.02 - 1.38) and timed rise (Incident Rate Ratio (IRR) = 1.24, 95% CI = 1.03 - 1.50). For predicting recurrent fallers Receiver Operator Characteristic (ROC) curves were as follows: 0.71 (95%CI 0.61-0.81) for timed up and go, 0.67 (95%CI 0.56-0.78) for timed rise and 0.70 (95%CI 0.60-0.80) for timed walk fast pace.

CONCLUSIONS

Timed rise was the single most important test that was able to predict both a first time faller and recurrent faller. Timed up and go was the most significant test to predict recurrent fallers.

Molecular biology of bone remodeling: implications for new therapeutic targets for osteoporosis

Osteoporosis is a major public health problem for adults over age 55 years costing billions of euros/dollars. Over the last 20 years anti-resorptive drugs were the treatment of choice for osteoporosis and most were derived from the bisphosphonate molecule. In the last 7 years remarkable advances in molecular biology and genetics have led to a detailed understanding of the bone remodeling cycle and as a result new therapeutic targets for treatment emerged. These new compounds have different modes of action depending on their role in the bone remodeling cycle. A major discovery was the important role of RANKL (receptor activator of nuclear factor kappa B ligand) secreted by osteoblasts and responsible for stimulating osteoclastic bone resorption. This led to development of a potent monoclonal antibody that blocks its action. This drug should be available soon as a new treatment for osteoporosis. Other molecular targets in resorption have been identified and several specific antagonists are potential treatments. However, a significant limiting factor for a new anti-resorptive drug is the cost of bringing it to the market because of the huge costs of a fracture trial. Although anti-resorptive agents have been the backbone of osteoporosis treatment they do not rebuild bone architecture and development of anabolic agents is needed. These are likely to evolve from an understanding of the LRP/Wnt signaling pathway. Already an antibody against sclerostin has shown promise in animal studies, and not to forget parathyroid hormone which was the first clinically useful anabolic treatment for osteoporosis.

Tibolone histology of the endometrium and breast endpoints study: design of the trial and endometrial histology at baseline in postmenopausal women

OBJECTIVE

To address the endometrial safety of tibolone.

DESIGN

The Tibolone Histology of the Endometrium and Breast Endpoints Study (THEBES) is a randomized, double-blind, parallel-group trial of tibolone compared with continuous combined conjugated equine estrogen (CEE) and medroxyprogesterone acetate (MPA).

SETTING

Multi-country, multi-center ambulatory care setting.

PATIENT(S)

A total of 5,185 subjects were screened, and biopsies were obtained from 4,446 women.

INTERVENTION(S)

Participants were randomized in a 1:1:2 ratio, to tibolone (1.25 or 2.5 mg/d) or CEE-MPA.

MAIN OUTCOME MEASURE(S)

The one-sided 95% confidence intervals for the incidence of hyperplasia or cancer were evaluated for tibolone compared with CEE-MPA.

RESULT(S)

Endometrial biopsy results at baseline: atrophic (87.29%), inactive (0.25%), proliferative (6.12%), secretory (2.86%), menstrual type (0.40%), and hyperplasia (0.18%). Only subjects with atrophic or inactive endometrium were eligible for this study, and 3% of the women at screening either had no tissue (0.18%) or had an amount of tissue that was insufficient for diagnosis (2.72%). Three thousand two hundred forty postmenopausal women with a mean (+/-SD) age of 54.4 +/- 4.4 years and a mean time since menopause of 4.5 +/- 3.6 years were randomized.

CONCLUSION(S)

The Tibolone Histology of the Endometrium and Breast Endpoints Study is a prospective, randomized clinical trial, designed to provide evidence of the endometrial safety of tibolone compared with estrogen and progestogen. Screening endometrial histology shows a low prevalence of endometrial hyperplasia (0.18%) and no carcinoma.

Falls are associated with decreased renal function and insufficient calcitriol production by the kidney

In a double blind placebo controlled 3-year osteoporosis study in elderly women, we collected prospective data on falls. The study population comprised 489 normal elderly women aged 65-77 years randomized to four groups: placebo, calcitriol 0.25 mcg b.i.d., conjugated equine estrogens (0.625 mg/day) and calcitriol+estrogen. Falls occurred in 57% of all women. Using a Poisson regression model, the placebo group with low GFR-creatinine clearance (CrCl<60 ml/min) had 60% more falls compared to the group with CrCl> or =60 ml/min. Further sub group analyses showed that there is no increased risk of falls with CrCl 60-70, 70-80 and >90 ml/min. Calcitriol treatment significantly reduced the number of falls by 50% (OR=0.5, 95% CI: 0.4-0.9, p=0.010) compared to placebo in the low CrCl group. The group with lower CrCl had lower calcium absorption (p<0.001), lower serum 1,25-dihydroxyvitamin D (1,25(OH)(2)D) (p<0.001) and normal serum 25OHD suggesting that there is decreased conversion of 25OHD to 1,25(OH)(2)D by the aging kidney. It is postulated that the decrease in falls on calcitriol therapy is related to an increase in serum 1,25(OH)(2)D, upregulation of VDR and improvement in muscle strength although one cannot exclude an effect on the central nervous system.

Endometrial effects of tibolone

BACKGROUND AND OBJECTIVES

The Tibolone Histology of the Endometrium and Breast Endpoints Study is a multicenter, randomized, double-blind study designed to address the conflicting reports in the literature about the endometrial safety of tibolone (1.25 or 2.5 mg/d). Tibolone was compared with continuous combined conjugated equine estrogen (CEE) plus medroxyprogesterone acetate (MPA) (0.625 + 2.5 mg/d).

METHODS

Subjects were randomized in a 1:1:2 ratio to tibolone 1.25 mg/d, 2.5 mg/d, and CEE/MPA, respectively. The one-sided 95% confidence interval (CI) has been evaluated for the incidence of abnormal endometrial histology (hyperplasia or carcinoma) and hyperplasia and carcinoma separately for each of the two treatment groups and the treatment groups combined after 1 and 2 yr of treatment with tibolone, compared with CEE/MPA.

RESULTS

A total of 3240 women were randomized, with 3224 receiving at least one dose of study medication. The incidence and upper one-sided 95% CI for the incidence of abnormal endometrium (hyperplasia or carcinoma), and hyperplasia and carcinoma separately, were calculated at end point, yr 1, and yr 2. The incidence (upper one-sided 95% CI) of abnormal endometrium at end point was 0.0 (0.5), 0.0 (0.4), and 0.2 (0.5) in the tibolone 1.25 mg, 2.5 mg, and CEE/MPA groups, respectively. During the entire treatment period, amenorrhea was reported more frequently with tibolone 1.25 mg (78.7%) and 2.5 mg (71.4%) than CEE/MPA (44.9%).

CONCLUSION

The Tibolone Histology of the Endometrium and Breast Endpoints Study results confirm previous findings that tibolone does not induce endometrial hyperplasia or carcinoma in postmenopausal women, and it is associated with a better vaginal bleeding profile than CEE/MPA.

Caffeine decreases vitamin D receptor protein expression and 1,25(OH)2D3 stimulated alkaline phosphatase activity in human osteoblast cells

Of the various risk factors contributing to osteoporosis, dietary/lifestyle factors are important. In a clinical study we reported that women with caffeine intakes >300 mg/day had higher bone loss and women with vitamin D receptor (VDR) variant, tt were at a greater risk for this deleterious effect of caffeine. However, the mechanism of how caffeine effects bone metabolism is not clear. 1,25-Dihydroxy vitamin D(3) (1,25(OH)(2)D(3)) plays a critical role in regulating bone metabolism. The receptor for 1,25(OH)(2)D(3), VDR has been demonstrated in osteoblast cells and it belongs to the superfamily of nuclear hormone receptors. To understand the molecular mechanism of the role of caffeine in relation to bone, we tested the effect of caffeine on VDR expression and 1,25(OH)(2)D(3) mediated actions in bone. We therefore examined the effect of different doses of caffeine (0.2, 0.5, 1.0 and 10mM) on 1,25(OH)(2)D(3) induced VDR protein expression in human osteoblast cells. We also tested the effect of different doses of caffeine on 1,25(OH)(2)D(3) induced alkaline phosphatase (ALP) activity, a widely used marker of osteoblastic activity. Caffeine dose dependently decreased the 1,25(OH)(2)D(3) induced VDR expression and at concentrations of 1 and 10mM, VDR expression was decreased by about 50-70%, respectively. In addition, the 1,25(OH)(2)D(3) induced alkaline phosphatase activity was also reduced at similar doses thus affecting the osteoblastic function. The basal ALP activity was not affected with increasing doses of caffeine. Overall, our results suggest that caffeine affects 1,25(OH)(2)D(3) stimulated VDR protein expression and 1,25(OH)(2)D(3) mediated actions in human osteoblast cells.

Response rate of bone mineral density to teriparatide in postmenopausal women with osteoporosis

PURPOSE

It is desirable for clinicians to know what bone mineral density (BMD) response they can expect in women treated with osteoporosis therapies. The focus of this analysis was to determine what percentage of women attained a lumbar spine BMD response to teriparatide that equaled or exceeded the least significant change (LSC) value of 3%.

METHODS

Data from three clinical trials involving postmenopausal women with osteoporosis were examined. The Fracture Prevention Trial was a double-blinded, placebo-controlled clinical trial examining the safety and efficacy of teriparatide 20 and 40 microg/day. The other two trials were double-blinded, head-to-head comparisons of alendronate 10 mg/day and teriparatide 20 or 40 microg/day, respectively. Only treatment-compliant women who had lumbar spine BMD measurements at all specified time points in these trials were included. For reference, we also examined the percentage of women with lumbar spine BMD responses to alendronate. Hip BMD responses that equaled or exceeded 3% were also examined.

RESULTS

According to the LSC criteria, 91% of the teriparatide 20 microg/day group and 94% of the teriparatide 40 microg/day group were lumbar spine BMD responders at 18 months in the Fracture Prevention Trial. In the teriparatide 20 microg/alendronate head-to-head trial, 94% of women receiving teriparatide had a lumbar spine BMD response that equaled or exceeded the 3% criterion at 18 months compared to 75% of those receiving alendronate 10 mg/day (p < 0.01). In the teriparatide 40 microg/day group of the other head-to-head trial, 92% of women achieved the 3% criterion for the lumbar spine at 12 months compared to 69% of those receiving alendronate 10 mg/day (p < 0.01). The median 3-month change in amino-terminal extension peptide of procollagen type 1 [PINP] in women who had a lumbar spine BMD response to teriparatide at 18 months was larger than in women who did not have a lumbar spine BMD response. However, the median 3-month PINP change in lumbar spine BMD nonresponders still exceeded the LSC value of 10 microg/L. Although the percentage of teriparatide-treated women with a hip BMD response that met the 3% criterion was significantly greater than for placebo, there was no significant difference between the percentage of teriparatide 20 microg/day and alendronate 10 mg/day responders in the comparison trial. The baseline characteristics of teriparatide lumbar spine responders and nonresponders were similar.

CONCLUSION

This analysis demonstrates that the vast majority of treatment-compliant postmenopausal women with osteoporosis and minimal prior bisphosphonate exposure have a lumbar spine BMD response to teriparatide that meets or exceeds the LSC. The characteristics of teriparatide responders and nonresponders were not significantly different; thus, we were unable to discern any characteristics that could be used to identify potential nonresponders.

Estrogen receptor alpha gene polymorphisms are associated with changes in bone remodeling markers and treatment response to estrogen

OBJECTIVES

Association studies between estrogen receptor alpha (ERalpha) gene polymorphisms and bone mineral density (BMD) have yielded inconsistent results. In the present study we evaluated the influence of XbaI and PvuII ERalpha gene polymorphisms on BMD, biochemical markers, rates of bone loss and the response to estrogen/hormone therapy (ET/HT) in elderly postmenopausal women.

METHODS

At baseline, we measured the association between ERalpha genotypes and BMD and biochemical markers in 489 elderly women, mean age 71 +/- 3 years. In the longitudinal study, the changes in the same measures were determined in 96 women on placebo and in 79 women receiving the ET/HT for 3 years. The XbaI and PvuII ERalpha polymorphisms were determined by polymerase chain reaction (PCR). BMD measurements for spine, femoral neck and total body were performed by DEXA, and biochemical indices were measured by standard methods.

RESULTS

Neither the PvuII nor the XbaI ERalpha gene polymorphisms were associated with baseline BMD and biochemical indices. In the longitudinal study, there were trends for higher bone loss in the placebo group in the genotypes pp or xx compared to PP or XX genotypes, but the changes were not significant. However, the changes in the bone markers were significantly (p < 0.05) higher in genotype group pp compared to PP (serum osteocalcin, 4.9 +/- 7.0% versus -13.4 +/- 6.7%; urine NTx:Cr ratio, 32.3+/-10.3% versus -2.5 +/- 10.3%) or xx compared to XX (serum osteocalcin, 7.5 +/- 6.4% versus -15.6+/-7.3%; urine NTx:Cr ratio, 39.4 +/- 9.2% versus -8.84+/-10.7%). At the end of 3 years, the mean urine NTx:Cr ratio was 78.7 +/- 9.0 versus 44.6 +/- 4.9 in pp versus PP (p < 0.05) and 75.5 +/- 10.7 versus 48.7 +/- 5.4 in xx versus XX (p < 0.05) genotypes. The response in total body BMD to ET/HT treatment was significantly higher in women with the PP genotype compared to pp genotype (2.48 +/- 0.55% versus 0.66 +/- 0.46%). Similar trends were seen at other skeletal sites for both XX and PP compared to pp and xx genotypes.

CONCLUSION

Women with ERalpha, PP and XX genotypes have lower bone remodeling, lower rates of bone loss and benefit more from hormone therapy.

Effect of Vitamin D supplement use on serum concentrations of total 25OHD levels in elderly women

Vitamin D(2) and D(3) are generally considered equipotent in humans. As Vitamin D(2) supplements are commonly used by elderly in United States, we determined the contribution of 25OHD(2) to the total serum 25OHD levels by HPLC in elderly women who reported taking Vitamin D(2) supplements (n = 56) and also in a group of randomly selected unsupplemented women (n = 60). In addition, we compared the total serum 25OHD measured by HPLC with competitive protein-binding assay (CPBA), a method routinely employed to measure Vitamin D status. A correlation of 0.91 (P < 0.001) was observed between the two methods for the serum total 25OHD measurement. The mean serum 25OHD level in Vitamin D(2) supplemented group was significantly higher than in unsupplemented group measured by HPLC (32 versus 28 ng/ml) and marginally higher measured by CPBA (33 vs. 31 ng/ml). Seventy eight percent of women taking Vitamin D(2) supplements had appreciable amounts of circulating 25OHD(2,) which constituted about 25 percent of their total serum 25OHD. It is also interesting to note that Vitamin D deficiency was less prevalent in elderly women taking Vitamin D(2) supplements (1.8%) compared to women not taking any supplements (12%).

The effects of calcitriol on falls and fractures and physical performance tests

There is an increase in the incidence of falls with aging and about 10% of falls lead to fractures. Nearly all hip fractures are due to falls and hip fractures are the most severe of the osteoporotic fractures because they lead to a 20% mortality rate and a loss of independent living in 50% of cases. Although there are multiple factors associated with falls, our interest is the role that vitamin D metabolism plays in the pathogenesis of falls. Recent clinical trials show that both vitamin D and the metabolite calcitriol reduce the number of falls by 30-40% in elderly subjects. This should also reduce the number of fractures. In European studies, the decrease in falls could be attributed to an improvement in the muscle weakness that often accompanies vitamin D deficiency. However, in the studies using calcitriol there was no vitamin D deficiency, so the mechanism of its efficacy is less clear. It could be due to increased muscle strength, an improvement in the neurological control of balance or both. Understanding these mechanisms would allow us to search for analogs of vitamin D that act more selectively on muscle and on the central nervous system.

Association between Vitamin D receptor polymorphisms and the rate of bone loss in elderly women-importance of adjusting for dietary and lifestyle factors

The association between the restriction length polymorphisms of the Vitamin D receptor (VDR) gene and the bone mineral density (BMD) or the rate of bone loss is still under debate. In a longitudinal study of untreated postmenopausal elderly women, we evaluated the relationship between the VDR gene polymorphisms (BsmI, TaqI, ApaI, and FokI) and the rate of bone loss over a 3-year period. We also examined the effect of adjustments for dietary and lifestyle factors on these associations. Before adjustments, the rate of femoral neck bone loss was - 3.76 +/- 1.58% in women with BB genotype and 0.45 +/- 0.65% in women with bb genotype, which was not significantly different. Upon adjustment for dietary and lifestyle factors, statistically significant (P = 0.03) bone loss was observed at femoral neck in women with BB genotype (- 3.66 +/- 2.44%) compared to that of bb genotype (2.39 +/- 1.32%). Similar results were observed with TaqI genotypes. The rates of bone loss at other skeletal sites were not different between VDR genotypes defined by BsmI and TaqI. VDR gene polymorphisms defined by ApaI and FokI were not related to the rate of bone loss.

Effect of vitamins D2 and D3 supplement use on serum 25OHD concentration in elderly women in summer and winter

Vitamin D2 and D3 are generally considered equipotent in humans. A few studies have reported that serum 25OHD levels are higher in vitamin D3- compared with vitamin D2-supplemented subjects. As both vitamin D2 and D3 supplements are commonly used by elderly in United States, in the present study we determined the effect of self-reported vitamin D2 and vitamin D3 supplement use on serum total 25OHD levels according to season in elderly women aged 65-77 years. Serum total 25OHD levels were determined in winter and summer in unsupplemented women ( N = 307) and in women who reported taking vitamin D2 ( N = 56) and vitamin D3 ( N = 55) supplements by competitive protein binding assay. In vitamin D2-supplemented women, the contribution of vitamin D2 and D3 to the mean serum total 25OHD level was assessed by HPLC. In summer, there were no significant differences in the mean total serum 25OHD levels (ng/ml) among the vitamin D2 (32 +/- 2.1), vitamin D3 (36.7 +/- 1.95), and unsupplemented (32.2 +/- 0.95) groups. In winter, the mean serum total 25OHD levels were higher in women on vitamin D2 (33.6 +/- 2.34, P < 0.05) and vitamin D3 (29.7 +/- 1.76, NS) supplements compared with unsupplemented women (27.3 +/- 0.72). In vitamin D2-supplemented women, about 25% of the mean serum total 25OHD was 25OHD2, in both summer and winter. Twelve percent of unsupplemented women and 3.6% of vitamin D-supplemented women had a mean serum total 25OHD level below 15 ng/ml in winter. In elderly subjects, both vitamin D2 and Vitamin D3 supplements may contribute equally to circulating 25OHD levels, with the role of vitamin D supplement use being more predominant during winter.

Caffeine intake increases the rate of bone loss in elderly women and interacts with vitamin D receptor genotypes

BACKGROUND

The role of caffeine as a risk factor for bone loss is controversial.

OBJECTIVE

Our goals were 1) to compare in both a cross-sectional study and a 3-y longitudinal study the bone mineral density (BMD) of postmenopausal women consuming high or low amounts of caffeine and 2) to study the interaction between caffeine intake, vitamin D receptor (VDR) polymorphism, and BMD in the longitudinal study.

DESIGN

The results are derived from cross-sectional measurements of BMD in 489 elderly women (aged 65-77 y) and from longitudinal measurements made in 96 of these women who were treated with a placebo for 3 y. Changes in BMD were adjusted for confounding factors and were compared between groups with either low (< or =300 mg/d) or high (>300 mg/d) caffeine intakes and between the VDR genotype subgroups of the low- and high-caffeine groups.

RESULTS

Women with high caffeine intakes had significantly higher rates of bone loss at the spine than did those with low intakes (-1.90 +/- 0.97% compared with 1.19 +/- 1.08%; P = 0.038). When the data were analyzed according to VDR genotype and caffeine intake, women with the tt genotype had significantly (P = 0.054) higher rates of bone loss at the spine (-8.14 +/- 2.62%) than did women with the TT genotype (-0.34 +/- 1.42%) when their caffeine intake was >300 mg/d.

CONCLUSIONS

Intakes of caffeine in amounts >300 mg/d ( approximately 514 g, or 18 oz, brewed coffee) accelerate bone loss at the spine in elderly postmenopausal women. Furthermore, women with the tt genetic variant of VDR appear to be at a greater risk for this deleterious effect of caffeine on bone.

Prevention of bone loss with tibolone in postmenopausal women: results of two randomized, double-blind, placebo-controlled, dose-finding studies

Tibolone, a novel compound with tissue-specific effects, has been found to have antiresorptive properties in bone. To confirm the efficacy of tibolone and determine its minimum effective dose for prevention of bone loss in early postmenopausal women, two randomized, double-blind, placebo-controlled, dose-finding studies were performed. Seven hundred seventy healthy women postmenopausal within 1-4 yr, with normal bone density for their age, were treated for 2 yr with 0.3, 0.625, 1.25, or 2.5 mg tibolone daily or placebo. All subjects took supplemental calcium carbonate (500 mg daily). Bone mineral density (BMD) of the lumbar spine and right proximal femur was measured by dual-energy x-ray absorptiometry for up to 2 yr. At each dose level, except the lowest (0.3 mg), tibolone produced a progressive increase in lumbar spine and total hip BMD over the 2-yr treatment period; at 0.3 mg, total hip density was maintained. However, only the doses 1.25 mg and 2.5 mg produced a progressive increase in femoral neck BMD. The differences in mean percent change from baseline in spine and total hip density were significant (P < 0.05) for all tibolone dose groups compared with placebo at all time points. Tibolone was well tolerated, with a similar overall incidence of adverse events compared with placebo. Tibolone 1.25 mg per day is recommended because it shows a positive and statistically significant change in BMD of spine and femoral neck.

Combination treatment with estrogen and calcitriol in the prevention of age-related bone loss

Estrogen deficiency and declining calcium absorption due to reduced calcitriol levels or intestinal resistance to calcitriol, are important factors in the pathogenesis of age-related bone loss. The main objective of this study was to examine the effect of estrogen and 1,25-dihydroxyvitamin D therapy given individually or in combination on bone loss in elderly women. Four hundred eighty-nine elderly women with normal bone density for their age, aged 65-77 yr, were entered into a randomized double blind, placebo-controlled trial. Women were randomized to one of four groups: conjugated estrogens (0.625 mg, daily) to women without a uterus (estrogen replacement therapy) plus medroxyprogesterone acetate (2.5 mg, daily) to women with a uterus (hormone replacement therapy), calcitriol (0.25 microg twice daily), a combination of hormone replacement therapy/estrogen replacement therapy plus calcitriol, or placebos for 3 yr. The primary outcome was the change in bone mineral density of the femoral neck and spine. In the intent to treat analysis, hormone therapy (hormone replacement therapy/estrogen replacement therapy) produced a mean (+/-1 SD) increase in bone mineral density of 2.98% (+/-5.45%) at the femoral neck (P < 0.0001) and 4.36% (+/-6.42%) at the spine (P < 0.0001). There were parallel increases in total hip and trochanter bone mineral density. Calcitriol increased bone mineral density 0.10% (+/- 4.27%) at the femoral neck (P = 0.57) and 1.65% (+/- 4.83%) at the spine (P < 0.0124). The combination of hormone replacement therapy/estrogen replacement therapy + calcitriol increased bone mineral density 3.80% (+/-4.95%) at the femoral neck (P < 0.001), 4.91% (+/-6.0%) at the spine (P < 0.0001), and parallel changes at the total hip and trochanter. All three treatment groups differed significantly from placebo at the spine and for the hormone replacement therapy/estrogen replacement therapy groups at the femoral neck, spine, total hip and trochanter. There were no significant differences between combination therapy and hormone replacement therapy/estrogen replacement therapy alone on bone mineral density at any site in the intent to treat analysis. In a secondary analysis of the effect in women who were adherent to treatment, calcitriol had a more significant effect on spine (P = 0.003) and total hip (P = 0.004). The increase in bone mineral density in the adherent groups of women was always higher compared with the intent to treat groups. Combination therapy compared with hormone replacement therapy/estrogen replacement therapy alone produced a significantly greater response in trochanter (P = 0.007) and total hip bone mineral density (P = 0.0017). In summary, hormone replacement therapy/estrogen replacement therapy alone and in combination with calcitriol therapy was highly effective in reducing bone resorption and increasing bone mineral density at the hip and other clinically relevant sites in a group of elderly women, with normal bone density for their age. Calcitriol was effective in increasing spine bone mineral density. In the adherent women, combination therapy with hormone replacement therapy/estrogen replacement therapy and calcitriol increased bone mineral density significantly more in the total hip and trochanter than did hormone replacement therapy/estrogen replacement therapy alone.

Role of estrogens in the management of postmenopausal bone loss

It is well known that estrogen deficiency is the major determinant of bone loss in postmenopausal women. Estrogen is important to the bone remodeling process through direct and indirect actions on bone cells. The largest clinical experience exists with estrogen therapy, demonstrating its successful prevention of osteoporosis as well as its positive influence on oral bone health, vasomotor and urogenital symptoms, and cardiovascular risk factors, which may not occur with other nonestrogen-based treatments. Compliance with HRT, however, is typically poor because of the potential side effects and possible increased risk of breast or endometrial cancer. Nevertheless, there is now evidence that lower doses of estrogens in elderly women may prevent bone loss while minimizing the side effects seen with higher doses of estrogen. Additionally, when adequate calcium, vitamin D, and exercise are used in combination with estrogen-based treatments, more positive increases occur in bone density. The benefits and risks of HRT must be assessed on a case-by-case basis, and the decision to use HRT is a matter for each patient in consultation with her physician. Estrogen-based therapy remains the treatment of choice for the prevention of osteoporosis in most postmenopausal women, and there may be a role for estrogen to play in the prevention of corticosteroid osteoporosis. Combination therapies using estrogen should probably be reserved for patients who continue to fracture on single therapy or should be used in patients who present initially with severe osteoporosis.

Alcohol intake and bone metabolism in elderly women

BACKGROUND

Published reports on the effect of alcohol consumption on bone mineral density (BMD) are inconsistent.

OBJECTIVE

The objective of this study was to examine the relation between alcohol intake and BMD, calcitropic hormones, calcium absorption, and other biochemical indexes of bone and mineral metabolism in elderly women.

DESIGN

The results presented are derived from baseline observations of 489 elderly women (aged 65-77 y) recruited for an osteoporosis study. The nondrinking group comprised 297 women and the drinking group comprised 148 women. Furthermore, the effect of different alcohol intakes (</=28.6, >28.6 to </=57.2, >57.2 to </=142.9, and >142.9 g/wk) was studied.

RESULTS

Women who consumed alcohol had significantly higher spine (10%), total body (4.5%), and midradius (6%) BMD than did nondrinkers. An alcohol intake >28.6 g/wk was associated with higher BMD; maximum effect was seen with an intake of >28.6 to </=57.2 g/wk (16%, 12%, and 14% increase in spine, total body, and midradius BMD, respectively). There was a marked reduction in bone remodeling markers, serum osteocalcin, and the ratio of urinary cross-linked N:-telopeptides of type 1 collagen to creatinine with alcohol consumption, suggesting that increased BMD with alcohol consumption could be due to reduced bone remodeling. Further, serum parathyroid hormone concentrations were significantly lower in alcohol drinkers than in nondrinkers and could be one of the causes of decreased bone resorption.

CONCLUSIONS

Moderate alcohol intake was associated with higher BMD in postmenopausal elderly women. The protective effect of alcohol may have been a result of lower bone remodeling due to reduced parathyroid hormone concentrations or factors such as increased estrogen concentrations.

Smoking and bone metabolism in elderly women

Cigarette smoking has been implicated as a risk factor for osteoporosis. In the present study, the relationship between smoking and bone mineral density, calcitropic hormones, calcium absorption, and biochemical indices related to bone and mineral metabolism was examined at baseline, in subjects recruited for an osteoporotic study. The subjects included 489 elderly women, aged 65-77 years. After exclusions (thiazide users), 54 women constituted the smoking group and 390 women were classified as nonsmokers. The effect of frequency of smoking was also examined in this population (33 light smokers [<1 pack/day] and 21 heavy smokers [>1 pack/day]). Adjusted mean total body bone mineral density was 4% lower (0.968 +/- 0.019 vs. 1.009 +/- 0.004) and the total hip density was 6% lower (0.778 +/- 0.024 vs. 0.826 +/- 0.006) in heavy smokers compared with nonsmokers. At the other sites measured (spine, midradius, femoral neck, trochanter, and Ward's triangle), a similar nonsignificant trend was observed. The adjusted mean calcium absorption corrected for weight was lower (13%) both in light and heavy smokers compared with nonsmokers, and serum 25-hydroxyvitamin D was significantly lower (16%) in heavy smokers than nonsmokers. Serum parathryroid hormone (PTH) was higher in heavy smokers, but was not significantly different from that of nonsmokers. A significant increase in bone remodeling markers, serum osteocalcin (4.35 +/- 0.271 vs. 3.79 +/- 0. 066) and urine N-telopeptide/creatinine (NTx/Cr) ratio (74.5 +/- 5. 75 vs. 49.8 +/- 1.4) was seen in heavy smokers compared with nonsmokers. These results suggest that smoking lowers bone mineral density, and is a result of decreased calcium absorption associated with secondary hyperparathyroidism and increased bone resorption.

Moderation of the daily dose of HRT: prevention of osteoporosis

INTRODUCTION AND METHODS

Osteoporosis is the most common bone disease in clinical practice. Between 30% and 50% of postmenopausal women and almost 50% of all people over the age of 75 are estimated to have osteoporosis. HRT is well known for reducing the risk of osteoporosis in postmenopausal women but compliance with long-term HRT therapy remains low. The use of low dose HRT reduces the estrogenic adverse events which often cause patients to stop therapy. In this paper, the current literature on the benefits of low dose HRT and osteoporosis prevention are reviewed.

RESULTS

Various studies have assessed the efficacy of low-dose HRT (25 mcg/day transdermally; 0.3 mg/day orally) in the prevention of osteoporosis. Low dose HRT is effective at reducing bone loss in postmenopausal and oophorectomised women. In one study of 218 postmenopausal women, a dose of 0.3 mg/day of esterified estrogen resulted in a small but significant increase in whole body BMD compared to a decrease in the placebo group. The addition of calcium supplements may have a synergistic effect on the reduction of bone loss.

CONCLUSION

Low dose estrogen, taken either orally or transdermally, can prevent or reverse postmenopausal bone loss and appears to be a useful alternative to higher dosages in the prevention and treatment of osteoporosis. The option of starting HRT at low dose gives physicians the ability to titrate doses to suit individual patients whilst ensuring adequate bone protection and the minimum of hyperestrogenic side effects.

Moderation of the daily dose of HRT: benefits for patients

INTRODUCTION

Hormone replacement therapy (HRT) has many benefits yet compliance rates remain low. One of the main reasons for discontinuing therapy is hyperestrogenic side effects which may be dose related, and the initiation of treatment is critical to a patient's chances of gaining long-term benefits. The introduction of low dose HRT means that physicians have an option to initiate or titrate patients to a low dose. The purpose of this review is to examine current literature on the benefits for patients of low dose HRT.

RESULTS

Low dose estrogen (25 mcg/day transdermally or 0.3 mg/day orally) are effective in controlling postmenopausal symptoms, reducing bone loss and reducing cardiovascular risk factors. Low dose therapy is also effective at reducing vasomotor symptoms in highly symptomatic women. In one study, patients on a daily dose of 25 mcg estrogen experienced an 86% reduction in vasomotor symptoms compared to a 55% reduction in patients on placebo. In addition, many adverse events related to estrogens were reduced using a low dose.

CONCLUSION

Compliance with traditional doses of HRT is currently a problem for many women who may stop taking therapy because they experience hyperestrogenic side effects. Low dose HRT is effective at reducing vasomotor symptoms and controlling symptoms even in highly symptomatic women. Hyperestrogenic side effects may be reduced by initiating treatment at the lowest dose and titrating upwards if necessary. This may have benefits for patients in terms of offering effective control of symptoms whilst minimising hyperestrogenic effects.

Evolution and analysis of model CPGs for walking: II. General principles and individual variability

Are there general principles for pattern generation? We examined this question by analyzing the operation of large populations of evolved model central pattern generators (CPGs) for walking. Three populations of model CPGs were evolved, containing three, four, or five neurons. We identified six general principles. First, locomotion performance increased with the number of interneurons. Second, the top 10 three-, four-, and five-neuron CPGs could be decomposed into dynamical modules, an abstract description developed in a companion article. Third, these dynamical modules were multistable: they could be switched between multiple stable output configurations. Fourth, the rhythmic pattern generated by a CPG could be understood as a closed chain of successive destabilizations of one dynamical module by another. A combinatorial analysis enumerated the possible dynamical modular structures. Fifth, one-dimensional modules were frequently observed and, in some cases, could be assigned specific functional roles. Finally, dynamic dynamical modules, in which the modular structure itself changed over one cycle, were frequently observed. The existence of these general principles despite significant variability in both patterns of connectivity and neural parameters was explained by degeneracy in the maps from neural parameters to neural dynamics to behavior to fitness. An analysis of the biomechanical properties of the model body was essential for relating neural activity to behavior. Our studies of evolved model circuits suggest that, in the absence of other constraints, there is no compelling reason to expect neural circuits to be functionally decomposable as the number of interneurons increase. Analyzing idealized model pattern generators may be an effective methodology for gaining insights into the operation of biological pattern generators.

Evolution and analysis of model CPGs for walking: I. Dynamical modules

Can one develop an abstract description of the dynamics of pattern generators that provides quantitative insight into their operation? We explored this question by examining the dynamics of a model central pattern generator that was created using an evolutionary algorithm. We propose an abstract description based on the concept of a dynamical module, a set of neurons that simultaneously make their transitions from one quasistable state to another while the synaptic inputs that they receive from other neurons remain essentially constant, thus temporarily reducing the dimensionality of the circuit dynamics. Using the mathematical tools of dynamical systems theory, we describe a method for identifying dynamical modules and demonstrate that this concept can be used to quantitatively characterize constraints on neural architecture, account for phase durations, and predict the effects of parameter changes. Moreover, this abstract description reveals coordinated parameter changes that leave the overall circuit dynamics essentially unchanged. In a companion article we employ this abstract description to examine the relationship between general principles and individual variability in large populations of evolved model pattern generators.

Efficacy and safety of low, standard, and high dosages of an estradiol transdermal system (Esclim) compared with placebo on vasomotor symptoms in highly symptomatic menopausal patients. The Esclim Study Group

OBJECTIVE

Our purpose was to evaluate the efficacy and safety of 3 dosages of Esclim, delivering 0.025 mg, 0.050 mg, or 0.100 mg 17beta-estradiol per 24 hours, in the treatment of moderate to severe vasomotor symptoms.

STUDY DESIGN

In this double-blind, placebo-controlled, parallel-group, multicenter trial, 196 highly symptomatic menopausal women received 12 weeks of continuous unopposed treatment with 1 of the 3 dosages of Esclim or a matching placebo patch.

RESULTS

The reduction in frequency of moderate to severe vasomotor symptoms was statistically significant compared with placebo (P <.05) from week 2 onward in the Esclim 50 and 100 groups and from week 3 onward in the Esclim 25 group. Symptom severity was also reduced. Estrogen-related adverse events, particularly metrorrhagia and endometrial hyperplasia, were less frequent in the Esclim 25 group than in the higher-dosage groups.

CONCLUSION

All 3 dosages of Esclim were effective in the treatment of vasomotor symptoms. The efficacy and safety of Esclim 25 indicate a good risk-benefit ratio.

Bone density, bone turnover, and hormone levels in men over age 75

BACKGROUND

Osteoporosis is a substantial problem in older men, with 25% of all hip fractures occurring in men. The mechanisms of bone loss in older men are unknown, but elevated parathyroid hormone (PTH) and diminished testosterone (T) levels are postulated as contributing factors.

METHODS

We measured bone mineral density (BMD), sex hormones, bone turnover markers, and calcium regulating hormones in a group of community-living men over the age of 75.

RESULTS

Thirty-five men (mean age 79; range 75-88 years) without disease or medication known to affect bone metabolism participated in the study. Whole body BMD was 1.21+/-.15 g/cm2; lumbar spine BMD (L1-L4) was 1.10+/-.15 g/cm2; femoral neck BMD was .77+/-.14 g/cm2; and trochanteric region was .71+/-.13 g/cm2. The femoral neck and trochanteric region values were more than 1 SD below the mean for adult men (age 25-33 years) in 28/35 and 15/35 men, respectively. Deoxypyridinoline levels were above the normal range for premenopausal women in 23% of the men; N-telopeptide and C-telopeptide demonstrated a wide scatter, but the values remained in the normal range. T levels were found to be below normal range for adult men in 12 of 32 (38%) subjects and the PTH levels above the normal range in 8 of 35 (23%) subjects. Bone resorption markers correlated inversely with BMD of the whole body, femur, and spine (r=-.22 to -.48). There was an inverse correlation between total T and spine BMD which became insignificant after correcting for body mass index (BMI). In addition, there was no correlation between free or bioavailable testosterone and BMD. 1,25-(OH)2D levels correlated inversely with BMD at the femur and whole body, but no association was found with PTH or 25 OH-D.

CONCLUSIONS

Men over 75 years of age had a wide range of BMD but frequently had low values at femoral sites. T levels were below the normal range in 38% of men, and PTH levels were elevated in 23% of men. There was an inverse correlation between total T and spine BMD which may have been dependent on the common effect of BMI. Bone mineral density was inversely related to markers of bone resorption.

Calciotropic hormones and bone markers in the elderly

There is a lack of substantial data on changes in calciotropic hormones and bone markers in elderly subjects living in North America. Parathyroid hormone (PTH), serum 25-hydroxyvitamin D (25(OH)D) and bone markers (serum osteocalcin and urine N-telopeptide), were measured in 735 Caucasian subjects (235 men and 500 women) aged 65-87 years. There was a significant increase in serum osteocalcin and urine N-telopeptide with age in men, and a significant increase in serum osteocalcin with age in women. Serum PTH and 25(OH)D showed no significant change with age in men or women. After adjusting for age, calcium intake, serum creatinine, season, and weight, mean serum PTH (p = 0.01), serum osteocalcin (p = 0.0001) and 24 h urine N-telopeptide (p = 0.0001) were higher in women than men, and mean serum 25(OH)D (p = 0.0001) and 24 h urine calcium (p = 0.0001) were higher in men than women. Serum PTH was correlated with serum osteocalcin in men and women, r = 0.24, r = 0.17, p < 0.001, but not with urine N-telopeptide. Serum PTH was inversely correlated with serum 25(OH)D (r = -0.25, r = -034,p < 0.001), and positively correlated with serum creatinine (r = 0.14, r = 0.17,p < 0.01) in men and women. The prevalence of serum 25(OH)D levels below 12 ng/ml was only 33% in females and 0.4% in men. Thus vitamin D deficiency was very uncommon in the U.S.A. compared with Europe. Although mean serum PTH was increased in the elderly, only 4-6% had PTH levels above the normal range. In summary, the increase in serum PTH in the elderly can be explained more by changes in vitamin D status than by declining renal function. These data also show significantly higher (p = 0.001) bone remodeling markers in women.

Dietary calcium and vitamin D intake in elderly women: effect on serum parathyroid hormone and vitamin D metabolites

In this study, the effect of dietary calcium and vitamin D on serum parathyroid hormone and vitamin D metabolites was measured in 376 free-living women aged 65-77 y. Mean calcium intake in both groups was close to the recommended dietary allowance of 800 mg/d. Mean vitamin D intake in the 245 women not taking vitamin D supplements was 3.53 microg/d (141 IU/d), which is below the recommended dietary allowance of 5 microg/d (200 IU/d). To test the hypothesis that vitamin D is more important than calcium in reducing serum parathyroid hormone, the source of dietary calcium intake was subdivided into milk, which is fortified with vitamin D, and nonmilk sources. The serum parathyroid hormone concentration was inversely correlated with calcium intake derived from milk (r = -0.20, P < 0.01) but not from nonmilk sources (r = -0.06). Furthermore, serum calcidiol correlated with milk calcium intake (r = 0.35, P < 0.001) but not with nonmilk calcium intake (r = 0.10). Multivariate analysis showed a significant effect of season on serum calcidiol but not on serum parathyroid hormone. Serum parathyroid hormone was inversely correlated with serum calcidiol (r = -0.33, P < 0.001) and the regression predicted that mean serum parathyroid hormone would be reduced in the elderly to concentrations considered normal in the young when serum calcidiol is 122 nmol/L (49 ng/mL); this would require a much higher recommended dietary allowance for vitamin D than 5 microg/d (200 IU/d).