Bazedoxifene improves renal function and increases renal phosphate excretion in patients with postmenopausal osteoporosis

INTRODUCTION

Because aging is a predictor of renal insufficiency in the general population, renal function is a concern in postmenopausal patients undergoing treatment for osteoporosis. Although high serum phosphate concentration is a predictor of renal insufficiency, the effect of selective estrogen receptor modulator (SERM) on renal function and phosphate homeostasis remains to be established.

MATERIALS AND METHODS

We administered 20 mg/day bazedoxifene to 48 postmenopausal osteoporotic women who had been taking alfacalcidol for ≥ 6 months, and assessed lumbar spine bone mineral density (LS-BMD), renal function (by calculating estimated glomerular filtration rate using serum cystatin-C levels [eGFRcys] [range 38.0-98.2 mL/min/1.73 m²]), and phosphate homeostasis.

RESULTS

LS-BMD was significantly higher 6 months after the initiation of bazedoxifene administration. eGFRcys had increased by 3 months after initiation and was stable until 12 months. Serum phosphate gradually decreased after initiation, reaching statistical significance at 6 months. The changes in serum phosphate were also significant when the maximum tubular reabsorption rate of phosphate was normalized to glomerular filtration rate (TmP/GFR), indicating that bazedoxifene treatment reduces serum phosphate by increasing the urinary excretion of phosphate. The change in eGFRcys after the initiation of bazedoxifene was significantly negatively correlated with the change in serum phosphate, suggesting that a reduction in serum phosphate improves renal function.

CONCLUSION

Bazedoxifene improves renal function, possibly by increasing renal phosphate excretion, in postmenopausal osteoporotic women without severe renal insufficiency.

The association of urinary pentosidine levels with the prevalence of osteoporotic fractures in postmenopausal women

To evaluate whether or not the urinary pentosidine level has clinical value in the assessment of the osteoporotic fracture risk, a novel ELISA for pentosidine was used in clinical samples. This study employed a cross-sectional design to analyze a subset of postmenopausal women in the Nagano Cohort Study. A total of 517 urine samples were analyzed using an ELISA system, which can measure urinary pentosidine without hydrolysis. Patients were asked about their history of non-vertebral osteoporotic fracture and the prevalence of vertebral fracture was semi-quantitatively assessed on X-ray films. A 10-year increase in age was related to a 1.09-fold increase in the urinary pentosidine level (95% CI 1.05-1.13, P < 0.001), prevalent fracture (+) was related to a 1.10-fold increase in the urinary pentosidine level (95% CI 1.03-1.18, P = 0.006). Patients with prevalent fracture who had a normal bone mineral density (BMD) showed higher pentosidine levels (median 34.3 pM/mg Cr) than patients with a low BMD without fracture (median 31.4 pM/mg Cr). A multivariable logistic regression analysis revealed that urinary pentosidine was significantly associated with the prevalence of fracture after adjustment for known risk factors for fracture (odds ratio 1.92, 95% CI 1.09-3.37, P = 0.023). The present results indicated a significant association between urinary pentosidine and fracture after adjustment for age and BMD, suggesting that urinary pentosidine may be useful for assessing the fracture risk in postmenopausal women.

Factors Influencing Serum Homocysteine Levels in Postmenopausal Osteoporotic Females - Comparison to Urinary Collagen Crosslinks

Purpose: The correlation between serum levels of homocysteine and bone mineral density remains controversial. The aim of this study was to identify the potential factors associated with the levels of serum total homocysteine (S-Hcy) and urinary N-terminal telopeptide of type I collagen (U-NTX) in female osteoporotic patients. Materials and Methods: This cross-sectional study included 163 female osteoporotic patients, aged between 48 and 91 years, who had never been treated with anti-osteoporosis therapy. Background data including spine and hip bone mineral density, ongoing therapy for the metabolic disease, aortic calcification score as evaluated by lateral lumbar X-ray film, and recent fragility fracture history were obtained. S-Hcy, U-NTX levels, and creatinine clearance were measured. Results: Multiple linear regression analysis revealed a significant correlation between S-Hcy levels and aortic calcification score (p = 0.022), creatinine clearance (p = 0.004), and recent fracture history (within 1 year after fracture) (p = 0.028); conversely, U-NTX levels correlated significantly with total hip bone mineral density (p < 0.0001) and recent fracture history (p = 0.0007). Conclusions: S-Hcy levels had no correlation with bone mineral density, but were associated with the degree of aortic calcification, renal function, and fracture events. These confounding factors should be taken into consideration when the relationship between S-Hcy and bone mineral density is discussed.

Urinary phytate concentration and risk of fracture determined by the FRAX index in a group of postmenopausal women

Background/aim

This study was designed to evaluate the relationship between urinary phytate concentration and risk of fracture at 10 years, determined by using the FRAX model, in women who had undergone menopause within 5 years of the time of enrollment.

Materials and methods

Of the 212 postmenopausal women evaluated, 69 were excluded because they had urinary phytate concentrations between 0.51 and 0.99 mg/L. Of the remaining 143 women, 91 had low (≤0.50 mg/L) and 52 had high (≥1.0 mg/L) urinary phytate concentrations. The 10-year risk of fracture was calculated by using the FRAX model.

Results

The risks of major osteoporotic fracture and hip fracture were higher in women with low urinary phytate levels (P < 0.001 in both cases). Evaluation of the risk of hip fracture in women with and without risk factors for osteoporosis (e.g., tobacco, alcohol, and drug consumption) and according to urinary phytate concentrations indicated that, among women with no risk factors, those with low and high urinary phytate levels had a range of risks of 0%–0.6% and 0%–0.3%, respectively (P = 0.098). Moreover, among women with at least one risk factor, those with low and high urinary phytate had a range of risks of 0.1%–0.8% and 0.1%–0.4%, respectively (P = 0.002). Similar results were observed when the risks of major osteoporotic fracture were analyzed.

Conclusion

These results indicate the relationship of phytate with the risks of major osteoporotic fracture and hip fracture, with these differences being more marked in women with risk factors for osteoporosis. From this study follows the importance of the consumption of phytate-rich products (nuts, legumes, whole cereals) to protect against the risk of fracture in 10 years, mainly in women with risk factors for osteoporosis.

Boron intake, osteocalcin polymorphism and serum level in postmenopausal osteoporosis

The relationship between daily boron intake and osteocalcin-mediated osteoporosis was studied in boron-exposed postmenopausal women. It is known that boron and osteocalcin are important in bone metabolism, however the effect of boron in bone metabolism has not been fully discovered. The study was performed on 53 postmenopausal women aged 55-60 living in parts of Balikesir, Turkey, where the subjects are naturally exposed to high (≥1 mg/L) or low (<1 mg/L) boron concentration in drinking water. 24-h urine samples were collected from all participants and creatinine clearance was detected. Boron intake levels of the subjects whose clearance levels were between 80-124 mL/min were measured by inductively coupled plasma-optical emission spectrometry (ICP-OES) in urine samples. Serum osteocalcin levels of the subjects were measured by osteocalcin enzyme-linked immunosorbent assay (ELISA) kit. Osteocalcin polymorphism rs1800247 was detected using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. Serum osteocalcin levels in boron-exposed postmenopausal women were significantly higher than that of control group (P ≤ 0.05) and the correlation between the serum osteocalcin level and rs1800247 polymorphism was not significant in both groups (P > 0.05). The differences in the distribution of osteocalcin genotypes and alleles in postmenopausal women were not significant between the boron exposed and the control groups (P > 0.05). Serum osteocalcin level in the CC genotype was significantly higher compared to the TC genotype in boron-exposed group (P ≤ 0.05). Our study suggests that daily boron intake of 1 mg/L may affect bone metabolism in postmenopausal women positively.

Restrictive pulmonary dysfunction is associated with vertebral fractures and bone loss in elderly postmenopausal women

Association between lung function and bone metabolism remains controversial. We found that impaired lung function was associated with vertebral fractures and bone loss in Japanese postmenopausal women. While vertebral deformities would impair lung function, respiratory dysfunction might in turn increase fracture risk, suggesting a complex bidirectional interaction.

INTRODUCTION

Association between bone metabolism and pulmonary function in the general population is controversial. The aim of this study was to investigate relationship between lung and bone parameters in elderly postmenopausal women.

METHODS

One hundred and six postmenopausal women (75.6 ± 8.0 years old) who underwent spirometric tests were examined for prevalent vertebral fractures, bone mineral density (BMD), bone metabolic markers, and other metabolic indices such as urinary pentosidine.

RESULTS

Multivariable logistic regression analyses revealed that forced vital capacity (FVC) (OR = 0.063, 95% CI: 0.011-0.352, p = 0.002) and urinary pentosidine (OR = 1.067, 95% CI: 1.020-1.117, p = 0.005) were associated with the presence of vertebral fractures after adjustment for height loss, age, and BMD at femoral neck. Moreover, vital capacity (VC) or FVC as well as body mass index and age was among independent determinants of BMD after adjustment for height loss and the number and grade of vertebral fractures in forced multiple linear regression analysis (VC: β = 0.212, p = 0.021, FVC: β = 0.217, p = 0.031). Urinary pentosidine was negatively correlated with pulmonary function parameters such as FVC and forced expiratory volume in 1 s (FEV_1.0), although these correlations appeared dependent on age.

CONCLUSIONS

Diminished FVC was associated with prevalent vertebral fractures and decreased BMD in Japanese postmenopausal women without apparent pulmonary diseases. Mechanism of such association between pulmonary function and bone status remains to be determined.

Pueraria mirifica alleviates cortical bone loss in naturally menopausal monkeys

Since the in vitro and in vivo anti-osteoporotic effects of Pueraria mirifica (PM) in rodents have been verified, its activity in menopausal monkeys was evaluated as required before it can be applicable for human use. In this study, postmenopausal osteoporotic monkeys were divided into two groups (five per group), and fed daily with standard diet alone (PMP0 group) or diet mixed with 1000 mg/kg body weight (BW) of PM powder (PMP1000 group) for 16 months. Every 2 months, the bone mineral density (BMD), bone mineral content (BMC) and bone geometry parameters (cortical area and thickness and periosteal and endosteal circumference) at the distal radius and proximal tibia were determined using peripheral quantitative computed tomography together with plasma and urinary bone markers. Compared with the baseline (month 0) values, the cortical, but not trabecular, BMDs and BMCs and the cortical area and thickness at the metaphysis and diaphysis of the radius and tibia of the PMP0 group continuously decreased during the 16-month study period. In contrast, PMP1000 treatment ameliorated the bone loss mainly at the cortical diaphysis by decreasing bone turnover, as indicated by the lowered plasma bone-specific alkaline phosphatase and osteocalcin levels. Generally, changes in the cortical bone geometry were in the opposite direction to the cortical bone mass after PMP1000 treatment. This study indicated that postmenopausal monkeys continuously lose their cortical bone compartment, and they have a higher possibility for long bone fractures. Oral PMP treatment could improve both the bone quantity (BMC and BMD) and quality (bone geometry).

Association of urinary sodium/creatinine ratio with bone mineral density in postmenopausal women: KNHANES 2008-2011

Accumulating evidence shows that high sodium chloride intake increases urinary calcium excretion and may be a risk factor for osteoporosis. However, the effect of oral sodium chloride intake on bone mineral density (BMD) and risk of osteoporosis has been inadequately researched. The aim of the present study was to determine whether urinary sodium excretion (reflecting oral sodium chloride intake) associates with BMD and prevalence of osteoporosis in postmenopausal women. This cross-sectional study involved a nationally representative sample consisting of 2,779 postmenopausal women who participated in the Korea National Health and Nutritional Examination Surveys in 2008-2011. The association of urinary sodium/creatinine ratio with BMD and other osteoporosis risk factors was assessed. In addition, the prevalence of osteoporosis was assessed in four groups with different urinary sodium/creatinine ratios. Participants with osteoporosis had significantly higher urinary sodium/creatinine ratios than the participants without osteoporosis. After adjusting for multiple confounding factors, urinary sodium/creatinine ratio correlated inversely with lumbar spine BMD (P = 0.001). Similarly, when participants were divided into quartile groups according to urinary sodium/creatinine ratio, the average BMD dropped as the urinary sodium/creatinine ratio increased. Multiple logistic regression analysis revealed that compared to quartile 1, quartile 4 had a significantly increased prevalence of lumbar spine osteoporosis (odds ratios 1.346, P for trend = 0.044). High urinary sodium excretion was significantly associated with low BMD and high prevalence of osteoporosis in lumbar spine. These results suggest that high sodium chloride intake decreases lumbar spine BMD and increases the risk of osteoporosis in postmenopausal women.

Evaluation of the anti-osteoporotic effects of metformin and sitagliptin in postmenopausal diabetic women

Osteoporosis is the most important metabolic bone disease in patients with diabetes mellitus. Several studies have documented that metformin is osteogenic in vitro. In contrast, others showed no effect of metformin on the osteogenic differentiation of bone marrow-derived mesenchymal stem cells. Incretin hormones have received much attention because of their beneficial effects beyond glycemia, including on bone health. The study evaluated the anti-osteoporotic effect of metformin and sitagliptin in postmenopausal diabetic women. Forty postmenopausal diabetic women were randomly divided into two equal groups. Group 1 received metformin (Glucophage(®) 500 mg) 1 tablet twice daily, and group 2 received sitagliptin (Januvia(®) 100 mg) 1 tablet/day, for 12 weeks. Fasting blood and urine samples were collected for measurement of serum total alkaline phosphatase (ALP), osteocalcin, and urinary deoxypyridinoline (DPD). Laboratory tests were measured at baseline, after 4 and 8 weeks, and at the end of the study. Bone mineral density of the anterior posterior lumbar spine was measured by dual energy X-ray absorptiometry at baseline and after 12 weeks of the intervention. In the metformin-treated group, the mean values for all markers of bone turnover at 12 weeks of treatment were not significantly different from baseline. In group 2, the mean serum total ALP was significantly decreased, serum osteocalcin levels were non-significantly decreased gradually by 10% at 12 weeks, while urinary DPD decreased significantly and was then maintained at 28% decrease at 12 weeks. In conclusion, metformin is neither osteogenic nor has anti-osteoporotic effect, while sitagliptin could positively regulate bone metabolism.

Adherence to raloxifene therapy: assessment methods and relationship with efficacy

Response to therapy depends on patient compliance but accurate assessment is difficult and adequate levels of adherence are uncertain. Adherence to raloxifene treatment may be assessed more accurately by electronic monitoring than by counting returned tablets. The level of adherence is positively associated with the degree of bone response.

INTRODUCTION

Adherence to study medication is usually estimated by counting returned tablets. This method relies on subjects' honesty and may be inaccurate. We aimed to assess adherence more accurately, and examine its effect on measures of bone response, by using electronic monitoring.

METHODS

Osteopenic women, ages 50 to 80, were prescribed daily raloxifene for 2 years. Electronic bottle caps (Medication Event Monitoring System (MEMS), Aardex) recorded the date and time on opening. Returned tablets were also counted. We measured bone mineral density (BMD) in duplicate at the spine and hip at baseline and 2 years. We also measured urinary N-terminal cross-linked telopeptide of type I collagen (NTX) at baseline, 1 and 2 years. We calculated the percentage changes in BMD and NTX from mean baseline to mean follow up measurements. Percentage adherence was assessed by both methods for 71 subjects that completed the study.

RESULTS

The two methods correlated significantly (p <0.001, Spearman's rho = 0.73) but the tablet count showed a higher median adherence than the MEMS caps (95.7 vs. 85.0%, p <0.001), with greater divergence at lower adherence levels. MEMS adherence in 65 subjects with complete data correlated with NTX response (p <0.01, rho = -0.33) but with BMD response only at the femoral neck. However, adherence in the lowest quartile was associated with poorer BMD response at all sites (p <0.05).

CONCLUSION

Tablet counts may give similar results overall but conceal substantial individual non-adherence. Monitoring caps may assess adherence more accurately than tablet counts and would be the preferred method in clinical trials. The degree of adherence is associated with both bone turnover and BMD responses to anti-resorptive therapy.

The relationship between fibroblast growth factor 23 and osteoporosis in postmenopausal women

AIM

A lack of estrogen in postmenopausal women is an important factor causing the development of osteoporosis. Our purpose is to investigate the effects of Fibroblast Growth Factor 23 (FGF-23) on bone mineral metabolism and bone turnover.

METHODS

Twenty-eight patients with postmenopausal osteoporosis (PMO), 32 patients with postmenopausal osteopenia and 30 healthy control subjects (postmenopausal non-osteoporosis) were included in this study. In order to assess the bone mineral metabolism; FGF 23, parathyroid hormone, vitamin D, calcium, phosphate, osteocalcin, alkaline phosphatase and hydroxyproline levels were measured.

RESULTS

FGF 23 levels were found significantly higher in PMO group compared with postmenopausal osteopenia and control groups (P<0.01 and P<0.05 respectively). Urine hydroxyproline level was detected to be significantly lower in PMO patients compared with control group (P<0.01). Lomber and femur BMD levels were found to be significantly lower in PMO patients compared with postmenopausal osteopenia and control groups (P<0.001, P<0.001; P<0.001, P<0.001 respectively). On the other hand, when we categorized the PMO group subjects according to the age of menopause, the FGF 23 levels were found to be significantly higher in the group of menopausal age <5 years compared to the group of menopausal age >10 and to the group of menopausal age 5-10 years (P<0.05, P<0.05).

CONCLUSION

We think our findings indicate that serum FGF 23 level is a significant determinant of increased bone turnover at early periods in PMO patients.

Changes in bone resorption across the menopause transition: effects of reproductive hormones, body size, and ethnicity

OBJECTIVE

Our objective was to characterize changes in bone resorption in relation to the final menstrual period (FMP), reproductive hormones, body mass index (BMI), and ethnicity.

METHODS

Urinary type I collagen N-telopeptide (NTX), estradiol, and FSH levels were measured annually for up to 8 years spanning the menopause transition in 918 African American, Chinese, Japanese, or Caucasian women.

RESULTS

Urinary NTX began to increase sharply about 2 years before the FMP, reaching its peak level about 1 to 1.5 years after the FMP. NTX levels declined modestly from 2 to 6 years after the FMP but remained about 20% higher than before the menopause transition. The sharp rise in FSH occurred in conjunction with a sharp decline in estradiol and shortly after FSH levels began increasing rapidly. The mean increase in urinary NTX across the menopause transition was greatest in women with BMI <25 kg/m² and smallest in women with BMI >30 kg/m². Increases in NTX were greatest in Japanese women and smallest in African Americans. These differences were attenuated, but not eliminated, when analyses were adjusted for covariates, particularly BMI.

SUMMARY

During the menopause transition, a decline in ovarian function beginning about 2 years before the FMP is followed by an increase in bone resorption and subsequently by bone loss. The magnitude of the increase in bone resorption is inversely associated with BMI. Ethnic differences in changes in bone resorption are attenuated, but not eliminated, by adjustment for BMI. Ethnic differences in BMI, and corresponding ethnic differences in bone resorption, appear to account for much of the ethnic variation in perimenopausal bone loss.

Evaluation of urinary N-telopeptide of type I collagen measurements in the management of osteoporosis in clinical practice

We measured urinary N-telopeptide of type I collagen (U-NTX) to monitor response to bisphosphonates for osteoporosis. Decrease in U-NTX was associated with increase in spine bone density. A lesser response in U-NTX was more likely in those with secondary osteoporosis or with poor compliance. U-NTX may be a useful early indicator of treatment non-compliance or secondary osteoporosis.

INTRODUCTION

This study aims to determine the utility of the bone resorption marker, U-NTX, in the clinical setting, to monitor the response to bisphosphonate therapy (alendronate and risedronate) for osteoporosis.

METHODS

A retrospective evaluation of data collected as part of the bone turnover marker monitoring service in the Metabolic Bone Centre, Sheffield, UK. Treatment compliance, underlying causes of osteoporosis, change in U-NTX/creatinine (Cr) at 4 months and change in spine and hip bone mineral density (BMD) by dual-energy X-ray absorptiometry were recorded. Treatment response was defined as either a change in U-NTX/Cr greater than a pre-defined least significant change (LSC) of 54 % or to within the lower half of a pre-defined pre-menopausal reference interval (≤ 30 nM BCE/mmol Cr).

RESULTS

A greater decrease in U-NTX/Cr at 4 months was associated with a greater increase in spine BMD at 18 months (r = -0.33; P < 0.0001, Pearson's correlation). The mean U-NTX/Cr at 4 months was higher in patients with secondary osteoporosis compared with those with primary osteoporosis (P < 0.01, ANOVA). A lesser response in U-NTX/Cr increased the likelihood of secondary osteoporosis or poor treatment compliance (P = 0.04, Fisher's exact test). A lack of response in U-NTX/Cr to within the lower half of the reference interval was a better indicator of secondary osteoporosis and treatment non-compliance than a change in U-NTX/Cr greater than LSC.

CONCLUSIONS

Treatment monitoring using U-NTX/Cr has a place in clinical practice for the early identification of non-compliance or presence of secondary osteoporosis.

A comparative study of the effects of daily minodronate and weekly alendronate on upper gastrointestinal symptoms, bone resorption, and back pain in postmenopausal osteoporosis patients

The purpose of the present study was to precisely compare both the efficacy and abdominal symptom-related quality of life after treatment with daily minodronate and weekly alendronate in patients with primary postmenopausal osteoporosis. The efficacy of the two drugs was assessed based on improvements in a bone turnover marker, back pain, and gastrointestinal symptoms that impair quality of life, which was assessed using the Izumo scale questionnaire. In the minodronate group, there were no significant changes during the treatment period in the specific scores for heartburn, epigastralgia and epigastric fullness, whereas all of the scores were significantly elevated at some time point after drug administration in the alendronate group. Urinary N-telopeptide of type I collagen (uNTX), a bone resorption marker, and bone-specific alkaline phosphatase, a bone formation marker, significantly decreased in both groups, but decreases in uNTX in the minodronate group was observed significantly earlier compared with those in the alendronate group. The back pain scores, which were obtained using a visual analog scale, were significantly reduced in both groups. However, analgesic effects were detected earlier in the minodronate group. In conclusion, compared with weekly alendronate, daily minodronate improved bone turnover and back pain more promptly without causing upper gastrointestinal symptoms.

Alfacalcidol-supplemented raloxifene therapy has greater bone-sparing effect than raloxifene-alone therapy in postmenopausal Japanese women with osteoporosis or osteopenia

Vitamin D insufficiency is prevalent in osteopenic and osteoporotic postmenopausal women. The persistent increase in circulating parathyroid hormone (PTH) caused by vitamin D insufficiency reduces bone density response to antiresorptive agents in these postmenopausal women. It is not well known whether administration of raloxifene might increase serum PTH secondary to the suppression of serum calcium in postmenopausal women with osteopenia or osteoporosis. We tried to assess whether raloxifene might affect serum PTH and whether the addition of alfacalcidol to raloxifene therapy could have favorable effects on bone mineral density (BMD) and bone turnover as compared to raloxifene-alone therapy in postmenopausal Japanese women with osteoporosis or osteopenia (≤2.0 SD based on young Japanese women). A total of 169 subjects were randomly assigned to groups receiving 60 mg raloxifene (R), or 1 μg alfacalcidol (D), or a combination of both (R + D) for 2 years. Serum levels of 25-hydroxyvitamin D [25(OH)D] were measured at randomization. The modified 'intention to treat' method was used. We compared the groups using a Tukey-Kramer test for changes in L- and TH-BMD and calcium metabolism when significant differences were found using one-way ANOVA. The parameters in each group during the experimental period were analyzed by means of paired t tests. Baseline 25(OH)D and i-PTH were 23.7 ng/ml and 38.4 pg/ml, respectively. At 6 months, i-PTH demonstrated a significant increase (+21.0%) in the R-group whereas significant decreases in i-PTH were observed in the D-group and combination-group (-15.9 and -8.9%, respectively). There were significant increases in L-BMD in the R + D-group (+4.1% at 1 year and +4.7% at 2 years, P < 0.0001) and in the R-group (+2.9% at 1 year and +2.8% at 2 years, P < 0.001), but the difference between the groups did not reach a significant level. Vitamin D status at randomization did not affect the subsequent BMD response in coadministration of alfacalcidol with raloxifene. Supplementation with alfacalcidol to raloxifene therapy demonstrates a greater bone-sparing effect by suppressing the secondary increment of serum PTH than when raloxifene is used alone.

[Comparative study of the urinary excretion of boron, calcium, magnesium and phosphorus in postmenopausal women with and without osteoporosis]

In order to compare the possible relationship between urinary concentrations of boron, calcium, magnesium and phosphorus in serum and urine of postmenopausal women with and without osteoporosis, we selected 45 postmenopausal women over 47 years of age, divided into two groups: group I clinically healthy postmenopausal women and group II postmenopausal women with osteoporosis, without chronic kidney and hepatic diseases or diabetes mellitus. We determined the boron (B), phosphorus (P), total calcium (Ca) and total magnesium (Mg) in the urine of two hours, by atomic emission spectroscopy with induction-coupled plasma (ICPA-ES). Total calcium and total magnesium in serum were determined by atomic flame absorption spectroscopy (FAAS) and inorganic phosphorus in serum, and creatinine in serum and urine, by molecular absorption spectrometry. The preliminary results suggest the existence of a significant difference (p < 0.05) in boron and phosphorus concentrations in the urine of two hours between the groups. The model of linear regression analysis used showed a relationship between urinary concentrations of boron/creatinine index and calcium/ creatinine, magnesium/creatinine and phosphorus/creatinine indexes in the urine of postmenopausal women with osteoporosis.

Variability in the measured response of bone to teriparatide

Apparent failures of bone mineral density (BMD) response to teriparatide at spine or hip occur even in a high compliance context (15% spine and 55% hip). Apparent non-responders nevertheless show good biomarker response, suggesting that apparent BMD non-response is due to measurement imprecision. Calcium intake may be an important determinant of hip response.

INTRODUCTION

Individuals vary in response to bone active agents, but that variability is poorly quantified and its basis is not well understood. The study included 203 postmenopausal women with moderately severe osteoporosis, all treated with teriparatide, calcium, and vitamin D. The study was performed at the Creighton University Medical Center, a single site.

METHODS

This is a prospective study of change in bone mineral density and resorption biomarkers over a 12-month treatment period. BMD response at spine and total hip was quantified by computing slopes for each participant's values, and biomarker change by the difference in values across the 12-month study period.

RESULTS

Of the total number of participants, 85.2% exhibited a significant spine BMD response, while only 44.8% had a significant change at the hip. However, mean biomarker response was marginally larger for the BMD non-responders at either site than for the responders, indicating biological, if not measurable densitometric, activity of teriparatide in essentially all participants.

CONCLUSIONS

Occasional apparent failures of BMD response in patients receiving teriparatide are probably not due to failure of response at the level of the bone remodeling apparatus, but instead reflect a combination of measurement imprecision and variable bone remodeling balance. The reason for the latter remains unclear.

Does anastrozole affect bone resorption similarly in early and late postmenopausal women?

The aim of this study was to determine whether the bone-resorption response to anastrozole differed according to initial patient age in postmenopausal women with breast cancer in a cross-sectional study. Second-morning void urines were collected for measurement of urinary cross-linked N-telopeptide of type I collagen (uNTx, corrected for creatinine and log-transformed) from postmenopausal women, 99 with breast cancer on anastrozole (ABC), 88 with newly diagnosed breast cancer (NDBC), and 137 community-dwelling healthy control (HC) women. Bone mineral density (BMD) was also measured at the lumbar spine (LS, L2-L4) and the femoral neck (FN) in the ABC group. uNTx (nanomole bone collagen equivalents/millimole creatinine) levels increased with age in HC subjects. In patients <70 years, anastrozole treatment led to a significant increase in uNTx compared with age-related HC subjects (1.74 vs. 1.55, P < 0.005). Patients >70 years showed no such increase compared to HC (1.72 vs. 1.69, nonsignificant); however, NDBC women >70 years had uNTx levels significantly lower than HC women (1.59 vs. 1.69, P < 0.05). There was no difference in uNTx levels above and below the age of 70 years in NDBC women (1.56 vs. 1.59, nonsignificant). ABC women were more likely to have a positive LS BMD z score than age-matched controls. Anastrozole treatment increases bone turnover more in younger postmenopausal women with breast cancer than in older women compared to healthy controls. Higher LS BMD in ABC patients may help protect against fracture.

Urinary deoxypyridinoline is a BMD-independent marker for prevalent vertebral fractures in postmenopausal women treated with glucocorticoid

SUMMARY

Urinary deoxypyridinoline (DPD) level was associated with prevalent vertebral fractures in glucocorticoid (GC)-treated postmenopausal women independently of lumbar spine bone mineral density (BMD).

INTRODUCTION

Bone metabolic indices are the potential predictors of bone fragility. However, their diagnostic efficiency for identifying the risk of GC-induced vertebral fractures is still unclear. We therefore evaluated whether bone metabolic indices would assess the risk of vertebral fractures in GC-treated women.

METHODS

One hundred seventy-five women treated with GC for more than 6 months were enrolled in this study.

RESULTS

Both premenopausal and postmenopausal women with vertebral fractures had significantly higher urinary DPD levels than those without vertebral fractures. When multivariable logistic regression analysis was performed with the presence of vertebral fractures as a dependent variable and each of DPD or osteocalcin level adjusted for age, weight, height, current and maximum doses of GC, duration of GC treatment, as well as lumbar spine BMD as an independent variable, DPD level was identified as a factor associated with the presence of vertebral fractures in postmenopausal women but not in premenopausal women.

CONCLUSION

Urinary DPD level was significantly associated with prevalent vertebral fractures in GC-treated postmenopausal women independently of lumbar spine BMD.

Effect of minodronic acid hydrate on hip geometry in Japanese women with postmenopausal osteoporosis

Dual-energy X-ray absorptiometry-based hip structural analysis was performed to evaluate the effect of a bisphosphonate, minodronic acid hydrate, on the geometry of the proximal femur in Japanese patients with osteoporosis. The subjects were 103 postmenopausal patients (average age 63.9 +/- 6.4 years) with primary osteoporosis. Minodronic acid hydrate was administered orally at a dose of 1 mg/day for 12 months. Significant early responses at 3-6 months after the start of administration were observed in all three regions of the proximal femur (narrow neck, intertrochanter, and shaft) in terms of bone density, geometry, and bone strength indices. The outcomes of therapy included a reduction of the internal diameter of the cortical bone (-0.1, -0.6, and -0.2% in the neck, intertrochanter, and shaft, respectively, at 12 months; not significant) and a significant increase in cortical thickness (3.1, 3.7, and 2.0% in the respective regions at 12 months). Furthermore, minodronic acid hydrate induced a significant enlargement of the cross-sectional bone area, which is related to compressive strength; a significant increase in cross-sectional moment of inertia and section modulus (SM 4.9, 5.8, and 2.9% in the neck, intertrochanter, and shaft, respectively, at 12 months; P < 0.001), which are related to the bending strength; and a significant reduction in buckling ratio (BR -3.0% (P < 0.001), -4.2% (P < 0.001), and -1.4% (P < 0.05) in the respective regions at 12 months), which reflects improved cortical stability. These findings show that minodronic acid hydrate reduces age-related endocortical bone resorption, leading to increased cortical thickness and sustained or enhanced bone strength.

Assessment of adherence to treatment of postmenopausal osteoporosis with raloxifene and/or alfacalcidol in postmenopausal Japanese women

Patients who are diagnosed with osteoporosis and beginning treatment often discontinue their osteoporosis medication relatively early after the start of treatment because of their poor recognition of fracture risk and the asymptomatic nature of osteoporosis. In this study we aimed to assess adherence to treatment with 1 microg alfacalcidol (D), 60 mg raloxifene (R) or a combination of both (D + R) for 1 year in postmenopausal Japanese women with osteoporosis or osteopenia. We defined persistence of D and R as continuing to take tablets for more than 7 of any 14 days immediately before the 1-year visit. A total of 137 subjects aged 49-81 years [64.9 +/- 7.0 years, 16.0 +/- 12.7 years since menopause (YSM)] were randomly assigned to each treatment group. The proportions persisting with each treatment group at 1 year were 61.4, 65.3, 55.1% for D, R and D + R groups, respectively whereas the compliance to each therapy as judged by the medical possession ratio (MPR) at 1 year were 77.5, 93.8, 78.4%, respectively. There were no significant differences in persistence, compliance and the number of subjects who discontinued treatment due to adverse events among each group. We found significant inverse correlations in percent changes at 1 year between compliance and serum BAP in R and D + R groups or urinary (u-) CTX in the R group. The changes in the level of serum BAP and u-CTX were significantly higher in high-compliance patients (MPR > 80%) treated with raloxifene alone or concomitantly with alfacalcidol compared to those in low-compliance patients.

Cadmium, follicle-stimulating hormone, and effects on bone in women age 42-60 years, NHANES III

BACKGROUND

Increased body burden of environmental cadmium has been associated with greater risk of decreased bone mineral density (BMD) and osteoporosis in middle-aged and older women, and an inverse relationship has been reported between follicle-stimulating hormone (FSH) and BMD in middle-aged women; however, the relationships between cadmium and FSH are uncertain, and the associations of each with bone loss have not been analyzed in a single population.

OBJECTIVES

The objective of this study was to evaluate the associations between creatinine-adjusted urinary cadmium (UCd) and FSH levels, and the associations between UCd and FSH with BMD and osteoporosis, in postmenopausal and perimenopausal women aged 42-60 years.

METHODS

Data were obtained from the Third National Health Examination and Nutrition Survey, 1988-1994 (NHANES III). Outcomes evaluated were serum FSH levels, femoral bone mineral density measured by dual energy X-ray absorptiometry, and osteoporosis indicated by femoral BMD cutoffs based on the international standard. Urinary cadmium levels were analyzed for association with these outcomes, and FSH levels analyzed for association with bone effects, using multiple regression. Subset analysis was conducted by a dichotomous measure of body mass index (BMI) to proxy higher and lower adipose-synthesized estrogen effects.

RESULTS

UCd was associated with increased serum FSH in perimenopausal women with high BMI (n=642; beta=0.45; p< or =0.05; R(2)=0.35) and low BMI (n=408; beta=0.61; p< or =0.01; R(2)=0.34). Among perimenopausal women with high BMI, BMD was inversely related to UCd (beta=-0.04; p< or =0.05) and FSH (beta=-0.03; p< or =0.05). In postmenopausal women with low BMI, an incremental increase in FSH was associated with 2.78 greater odds for osteoporosis (109 with and 706 without) (OR=2.78; 95% CI=1.43, 5.42; p< or =0.01).

CONCLUSION

Long-term cadmium exposure at environmental levels is associated with increased serum FSH, and both FSH and UCd are associated with bone loss, in US women aged 42-60 years.

Evidence-based guidelines for the use of biochemical markers of bone turnover in the selection and monitoring of bisphosphonate treatment in osteoporosis: a consensus document of the Belgian Bone Club

OBJECTIVES

To review the clinical value of bone turnover markers (BTM), to initiate and/or monitor anti-resorptive treatment for osteoporosis compared with bone mineral density (BMD) and to evaluate suitable BTM and changes in BTM levels for significance of treatment efficiency.

METHODOLOGY

Consensus meeting generating guidelines for clinical practice after review and discussion of the randomised controlled trials or meta-analyses on the management of osteoporosis in postmenopausal women.

RESULTS

Although the correlation between BMD and BTM is statistically significant, BTM cannot be used as predictive markers of BMD in an individual patient. Both are independent predictors of fracture risk, but BTM can only be used as an additional risk factor in the decision to treat. Current data do not support the use of BTM to select the optimal treatment. However, they can be used to monitor treatment efficiency before BMD changes can be evaluated. Early changes in BTM can be used to measure the clinical efficacy of an anti-resorptive treatment and to reinforce patient compliance.

DISCUSSION

Determining a threshold of BTM reflecting an optimal long-term effect is not obvious. The objective should be the return to the premenopausal range and/or a decrease at least equal to the least significant change (30%). Preanalytical and analytical variability of BTM is an important limitation to their use. Serum C-terminal cross-linked telopeptide of type I collagen (CTX), procollagen 1 N terminal extension peptide and bone specific alkaline phosphatase (BSALP) appear to be the most suitable.

CONCLUSION

Consensus regarding the use of BTM resulted in guidelines for clinical practice. BMD determines the indication to treat osteoporosis. BTM reflect treatment efficiency and can be used to motivate patients to persist with their medication.

Short-term administration of water-soluble silicon improves mineral density of the femur and tibia in ovariectomized rats

Silicon is important for the proper growth and development of bone and connective tissues. This study was designed to investigate if water-soluble silicon could be used for the treatment of postmenopausal osteoporosis. Silicon (Si 20 mg/kg body weight/day) was administrated orally to 17-week-old ovariectomized (OVX) rats for 4 weeks. Silicon did not alter weight gain in OVX rats. Silicon supplementation significantly increased the bone mineral density of the femur (p < 0.05, vs. OVX control group) and tibia in OVX rats (p < 0.05, vs. OVX control group). Serum alkaline phosphatase and osteocalcin, two bone formation biomarkers tested, were not significantly altered, but urinary calcium and phosphorous excretion tended to decrease with silicon supplementation. OVX rats with silicon supplementation showed a relatively higher serum CTx compared to the nonsupplemented OVX group (p < 0.01, vs. OVX control group). According to these results, short-term soluble silicon supplementation improved bone mineral density in OVX-induced osteoporosis.

Bone structural effects of variation in the TNFRSF1B gene encoding the tumor necrosis factor receptor 2

The 1p36 region of the human genome has been identified as containing a QTL for BMD in multiple studies. We analysed the TNFRSF1B gene from this region, which encodes the TNF receptor 2, in two large population-based cohorts. Our results suggest that variation in TNFRSF1B is associated with BMD.

INTRODUCTION

The TNFRSF1B gene, encoding the TNF receptor 2, is a strong positional and functional candidate gene for impaired bone structure through the role that TNF has in bone cells. The aims of this study were to evaluate the role of variations in the TNFRSF1B gene on bone structure and osteoporotic fracture risk in postmenopausal women.

METHODS

Six SNPs in TNFRSF1B were analysed in a cohort of 1,190 postmenopausal Australian women, three of which were also genotyped in an independent cohort of 811 UK postmenopausal women. Differences in phenotypic means for genotype groups were examined using one-way ANOVA and ANCOVA.

RESULTS

Significant associations were seen for IVS1+5580A>G with BMD and QUS parameters in the Australian population (P = 0.008 - 0.034) and with hip BMD parameters in the UK population (P = 0.005 - 0.029). Significant associations were also observed between IVS1+6528G>A and hip BMD parameters in the UK cohort (P = 0.0002 - 0.003). We then combined the data from the two cohorts and observed significant associations between both IVS1+5580A>G and IVS1+6528G>A and hip BMD parameters (P = 0.002 - 0.033).

CONCLUSIONS

Genetic variation in TNFRSF1B plays a role in the determination of bone structure in Caucasian postmenopausal women, possibly through effects on osteoblast and osteoclast differentiation.

Bone turnover and bone collagen maturation in osteoporosis: effects of antiresorptive therapies

Bone collagen maturation may be important for anti-fracture efficacy as the reduction in risk is only partly explained by a concomitant increase in BMD during anti-resorptive therapy. Different treatments caused diverse profiles in bone collagen degradation products, which may have implications for bone quality.

INTRODUCTION

The aim of the present study was to evaluate the effect of different anti-resorptive treatments on bone collagen maturation measured as the ratio between the degradation products of newly synthesized and mature isomerized C-telopeptides of type I collagen.

METHODS

Participants were from cohorts of healthy postmenopausal women participating in double blind, placebo-controlled 2-year studies of alendronate, ibandronate, intranasal hormone replacement therapy (HRT), oral HRT, transdermal HRT, or raloxifene (n = 427). The non-isomerized alphaalphaCTX and isomerized betabetaCTX were measured in urine samples obtained at baseline, and after 6, 12, and 24 months of therapy.

RESULTS

Bone collagen maturation measured as the ratio between alphaalphaCTX and betabetaCTX showed that bisphosphonate treatment induced a collagen profile consistent with an older matrix with a 52% (alendronate) and 38% (ibandronate) reduction in the ratio between the two CTX isoforms vs. 3% and 15% with HRT or raloxifene, respectively.

CONCLUSIONS

Anti-resorptive treatments had different effects on the endogenous profile of bone collagen maturation. Whether that effect on bone collagen has an impact on bone strength independent on the treatment-dependent effect on BMD should be investigated.

Elevations in serum and urinary calcium with parathyroid hormone (1-84) with and without alendronate for osteoporosis

CONTEXT

The effect of PTH therapy on serum and urinary calcium levels and the risk of hypercalcemia or hypercalciuria has not been formally evaluated.

OBJECTIVE

The objective was to examine changes in serum and urinary calcium associated with PTH(1-84) therapy in the PaTH trial and the extent to which a defined algorithm resolved the elevated values.

DESIGN, SETTING, PARTICIPANTS, AND INTERVENTION

A total of 178 postmenopausal women were randomized to PTH(1-84) either alone or in combination with alendronate during the first year of the PaTH study.

MAIN OUTCOME MEASURE(S)

The main outcome measures were fasting serum calcium at baseline and 1, 3, and 12 months and 24-h urinary calcium at baseline and 3 months.

RESULTS

In 14% of participants, serum calcium more than 10.5 mg/dl (>2.6 mmol/liter) developed. Following the defined algorithm, 58% of elevated measurements were normal on repeat testing; 38% required discontinuation of calcium and vitamin D supplementation, and one necessitated a decrease in PTH injection frequency to normalize serum calcium. One participant developed transient hypercalcemia between study visits and required hospitalization; the episode resolved with iv hydration and PTH discontinuation. Baseline characteristics associated with the development of hypercalcemia were serum calcium [relative hazards = 1.9 per 0.5 mg/dl (0.12 mmol/liter); 95% confidence interval = 1.1-3.2] and serum 1,25-dihydroxyvitamin D [relative hazard = 1.9 per 10 pg/ml (26 pmol/liter); 95% confidence interval = 1.2-3.1]. Fifteen women (8%) developed hypercalciuria [urinary calcium > 400 mg (100 mmol)/24 h or calcium/creatinine ratio > 0.4]; 80% of cases resolved after discontinuing calcium and vitamin D, 13% without intervention, and one after PTH injection frequency was decreased. Higher baseline urinary calcium excretion was associated with development of hypercalciuria [relative hazard = 1.5 per 50 mg/d (12.5 mmol/d); 95% confidence interval = 1.2-4.0]. Proportions of patients with elevated serum and urinary calcium were similar on single and combination therapy.

CONCLUSIONS

The frequency of episodic hypercalcemia or hypercalciuria in the PaTH trial was 21%. Episodes were generally mild, and nearly all cases resolved spontaneously or with discontinuation of calcium and vitamin D. The algorithms used to address hypercalcemia and hypercalciuria in the PaTH trial proved effective in safely resolving clinical episodes of increased urinary or serum calcium and might therefore be helpful to clinicians caring for patients on PTH.

[The effect of risedronate treatment on bone turnover markers in patients with hip fracture]

OBJECTIVES

The effect of risedronate treatment on bone resorption was investigated quantitatively by measuring N-telopeptide levels in urine of patients with hip fracture.

METHODS

Forty-six women (mean age 75 years) who underwent surgical treatment for intertrochanteric or femoral neck fractures due to minor trauma were divided into two groups according to the order of presentation. One group (26 patients; mean age 77+/-5 years) received oral risedronate 5 mg/day after the fifth postoperative day, while the other group (20 patients; mean age 73+/-6 years) received no drug treatment. Patients who had been on treatment for Paget's disease or osteoporosis or those with renal failure were excluded. Urine samples were collected from all the patients on the second day of hospitalization and at the end of three months to measure N-telopeptide levels, one of the bone turnover markers, with the use of the Osteomark NTx ELISA laboratory kit.

RESULTS

The mean urine N-telopeptide level decreased by 49.7% at the end of three months of treatment with risedronate (p<0.0001), whereas there was a 5.8% increase in the N-telopeptide level of the control group. The two groups differed significantly with respect to the levels of bone resorption at the end of three months (p<0.0001).

CONCLUSION

Risedronate treatment was found effective in decreasing bone resorption and thus in reducing the risk for refractures in patients with hip fractures due to minor trauma.

Urinary gamma-glutamyltransferase (GGT) as a potential marker of bone resorption

We recently identified gamma-glutamyltransferase (GGT) as a novel bone-resorbing factor. The present study was undertaken to determine whether GGT is a marker of bone resorption in two genetic models of hyper- and hypo-function of osteoclasts, as well as in postmenopausal women with accelerated bone resorption, using type I collagen N-telopeptide (NTX) and deoxypyridinoline (DPD) as established biochemical markers. Urinary excretion of GGT, corrected for creatinine, was found to be increased in osteoprotegerin (OPG)-deficient osteoporotic mice as well as in patients with postmenopausal osteoporosis (67-83 years of age); in both cases the urinary level decreased after treatment of patients or mice with alendronate, a selective inhibitor of bone resorption, concomitantly with a reduction in DPD and NTX. Conversely, in osteopetrotic op/op mice, urinary GGT increased in parallel with DPD after induction of osteoclasts with M-CSF injection. Constant infusion of parathyroid hormone (PTH) also increased urinary GGT along with DPD. In a survey of 551 postmenopausal women (50-89 years of age) at their regular health checkup, urinary GGT excretion exhibited a high correlation with DPD (rho = 0.49, p < 0.0001). The calculated sensitivity and specificity for diagnosing elevated bone resorption, as determined by a DPD value higher than 7.6 nM/mM Cr, were 61% and 92%, respectively, when a cut-off value of 40 IU/g Cr was assigned for urinary GGT. Since GGT activity can be measured inexpensively in large numbers in a very short time, the measurement of urinary level may provide a convenient and useful method for mass screening to identify those with increased bone turnover and hence at increased risk for bone fracture.

Effect of vitamin K2 treatment on carboxylation of osteocalcin in early postmenopausal women

OBJECTIVE

We examined the serum level of undercarboxylated osteocalcin (uc OC), which is a sensitive marker of vitamin K status, and levels of bone turnover markers in early postmenopausal women receiving vitamin K2 treatment with or without vitamin D3.

METHODS

Thirty-four postmenopausal women with a mean age of 53 years whose bone mineral density (BMD) was less than 0.809 g/cm2 (osteopenia and osteoporosis) were treated with vitamin K2 or with a combination of vitamin K2 and vitamin D3. Seventeen women received daily oral administration of 45 mg vitamin K2 and 17 women received daily oral administration of 45 mg vitamin K2 plus 0.75 microg 1alpha-hydroxyvitamin D3. Serum levels of uc OC, intact osteocalcin (OC) and bone alkaline phosphatase (BAP), urinary deoxypyridinoline (DPD) levels and BMD at the lumbar spine were measured before and at 1 and 2 years after the start of treatment.

RESULTS

Serum uc OC levels in women treated with vitamin K2 alone and with both vitamin K2 and vitamin D3 decreased significantly (p < 0.05). Serum levels of intact OC and BAP in women treated with vitamin K2 did not show significant changes, while those in women who received the combined treatment decreased significantly (p < 0.05). On the other hand, urinary DPD level in women treated with vitamin K2 did not change, while that in women who received the combined treatment tended to decrease (p < 0.1).

CONCLUSION

Serum uc OC levels in early postmenopausal women who received vitamin K2 decreased due to carboxylation of uc OC. Combined treatment with vitamin K2 and vitamin D3 may be effective for sustaining BMD in early postmenopausal women whose bone turnovers are highly activated.

[Is there a role for a random measurement of 24-hour urine calcium excretion and serum total alkaline phosphatase in the determination of fracture risk in osteoporotic postmenopausal women?]

Our objective was to explore whether a casual determination of 24-hour urinary calcium excretion and serum total alkaline phosphatase (TAP), in osteoporotic postmenopausal women are independent predictors for osteoporotic fracture. Subjects were 121 women with postmenopausal osteoporosis (mean age 62.8 +/- 9.9) segregated in two study groups based on prevalence of osteoporotic fractures (51 women with prevalent fractures and 70 without fractures), similar in terms of age and BMI. We measured bone mineral density (BMD) by DXA at lumbar spine and femoral neck. Vertebral fracture assessment was done by plain X ray evaluation. Routine blood tests and extensive endocrine evaluation were performed in all patients to exclude secondary causes of osteoporosis. Serum TAP, calcium, phosphate and urinary calcium excretion was measured to evaluate bone metabolism. We did not find any significant differences between groups regarding lumbar T score (-3.1/-2.9 SD), femoral neck T score (-2.2/-1.8 SD), lumbar Z score (-1.5/-1.9 SD) or femoral neck Z score (-1.5/-1.8 SD). Serum TAP was higher in fracture group (211.5 UI) comparing to non-fracture osteoporotic women (208.3 UI) without statistical significance. We were not able to find any significant difference between groups in terms of urinary calcium excretion (9.13/5.4 mEq/24h) or serum total calcium (4.8/4.9 mmol/l).

CONCLUSION

in spite of a mean TAP near the upper limit of normal range which could be related to low bone mass, there is no significant relationship to fracture risk in osteoporotic postmenopausal women. Based on our data, a casual measurement of urinary calcium excretion seems irrelevant for BMD independent fracture risk assessment in this clinical setup.

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.

[Age-related and menopause-related changes of urinary excretion of C- and N-terminal cross-linked telopeptides of type I collagen and the relationships thereof with menopause-related bone loss]

OBJECTIVE

To study the age-related and menopause-related changes of urinary excretion of C- and N-terminal cross-linked telopeptides of type I collagen (uCTX/Cr and uNTX/Cr) and the relationships thereof with menopause state, years after menopause, bone mineral density (BMD), and menopause-related bone loss in healthy women.

METHODS

ELISA was used to examine the uCTX/Cr and uNTX/Cr of 659 female volunteers aged 20 - 80 in Changsha. Dual energy X-ray absorptiometry (DXA) was used to measure the BMD of various skeletal sites, including the lumbar vertebrae (L1 - L4) at anteroposterior (AP) position, L(2) - L(4) at lateral (LAT) position, hip, and forearm. 339 postmenopausal women among the 659 subjects were divided into 3 groups, osteoporotic, osteopenic, and normal groups according to the WHO criteria of osteoporosis diagnosis.

RESULTS

(1) Both the curves of uCTX/Cr and uNTX/Cr with age were fit the best by regression analysis of cubic equation. The coefficients of determination (R(2)) were 0.139 for uCTX/Cr and 0.149 for uNTX/Cr. The levels of uCTX/Cr and uNTX/Cr of the women aged > 35 increased with age. (2) The values of uCTX/Cr and uNTX/Cr were 253 mg/mol +/- 101 mg/mol Cr and 63 nmol +/- 34 nmol BCE/mmol Cr respectively in the postmenopausal women, remarkably higher than those of the premenopausal women (149 mg/mol +/- 80 mg/mol Cr and 33 nmol +/- 17 nmol BCE/mmol Cr respectively), increased by 69.5% and 93.4% respectively. The annual change rates of uCTX/Cr and uNTX/Cr were the highest within the first 5 years after menopause, and these increases were in agreement with the significant decrease of BMD at most skeletal sites by 10.8% approximately 27.6%. (3) After controlled for age and body weight, both uCTX/Cr and uNTX/Cr showed significant negative correlation with BMD (r = -0.078 to -0.283, P < 0.05 or 0.01), and there was a significant positive correlation between uCTX/Cr and uNTX/Cr. (4) The elevation of the levels of uCTX/Cr and uNTX/Cr in the osteoporotic and osteopenic postmenopausal subgroups were significantly higher than those in the postmenopausal women with normal BMD (P < 0.05 or 0.01). For example, the uCTX/Cr levels of the osteoporotic, osteopenic, and normal BMD subgroups according to the DXA results at the anteroposterior lumbar spine were 189 +/- 87, 272 +/- 108, and 366 +/- 135 mg/mol Cr respectively, while the uNTX/Cr levels were 52 +/- 22, 68 +/- 34 and 108 +/- 41 nmol BCE/mmol Cr respectively.

CONCLUSION

uCTX/Cr and uNTX/Cr can be used as sensitive markers to determine the bone turnover status, which is changeable with age and menopausal status in women. They present a significantly negative correlation with BMD, and increase significantly in the postmenopausal women with osteopenia or osteoporosis, which indicates that measuring uCTX/Cr and uNTX/Cr can predict age-related and menopause-related bone loss in women.

Loop diuretics increase bone turnover and decrease BMD in osteopenic postmenopausal women: results from a randomized controlled study with bumetanide

To study effects of loop diuretics on bone, 87 women were randomized to 1 year of treatment with bumetanide or placebo. Compared with placebo, bumetanide decreased BMD by 2% at the total hip and by 1.4% at the whole body. Levels of biochemical bone markers were lower in the placebo than in the bumetanide group. Thus, treatment with loop diuretics affects bone metabolism.

INTRODUCTION

Loop diuretics may affect bone because they increase the renal calcium excretion and alters the diurnal rhythm of plasma PTH levels. We studied the effects of 1 year of treatment with the loop diuretic bumetanide on bone metabolism.

MATERIALS AND METHODS

In a double-blinded design, 87 healthy postmenopausal women with osteopenia were randomized to 1-year bumetanide treatment 2 mg/day or placebo. BMD, plasma levels of calcitropic hormones, and biochemical bone markers were measured at baseline, after 1 year of treatment (week 52), and 6 months after withdrawal of treatment (week 78). Calcium (800 mg/day) and vitamin D (10 microg/day) were administered to all participants during the entire 1.5-year study period.

RESULTS

Compared with placebo, urinary calcium (+17%) and plasma PTH levels (+9%) increased significantly in response to bumetanide. After 1 year of treatment, BMD in the bumetanide compared with the placebo group was significantly decreased by 2% at the total hip and ultradistal forearm and by 1.4% at the whole body. In addition, levels of biochemical markers of bone turnover differed significantly (approximately 20%) between groups, with lower levels in the placebo than in the bumetanide group. Six months after the end of treatment, the effects of bumetanide were weakening.

CONCLUSIONS

Treatment with loop diuretics affects bone turnover and decreases BMD. Further studies may reveal whether loop diuretics should be considered as a risk factor for fracture.

Monthly oral ibandronate is well tolerated and efficacious in postmenopausal women: results from the monthly oral pilot study

CONTEXT

Ibandronate, a potent, nitrogen-containing bisphosphonate developed for intermittent administration in postmenopausal osteoporosis, aims to overcome current adherence issues with daily and weekly oral bisphosphonates through once-monthly oral dosing.

OBJECTIVE

The purpose of this study was to investigate the safety, pharmacodynamics, and pharmacokinetics of once-monthly oral ibandronate.

DESIGN

A randomized, 3-month, double-blind, placebo-controlled, phase I study (Monthly Oral Pilot Study) was conducted.

SETTING

The study was conducted at five clinical trial centers in the United Kingdom and Belgium.

PATIENTS OR OTHER PARTICIPANTS

Subjects were postmenopausal women (age, 55-80 yr; > or =3 yr post menopause; n = 144).

INTERVENTION(S)

Once-monthly oral ibandronate 50, 100, or 150 mg or placebo was used. After the first cycle, the 50-mg arm was split, with participants continuing on either 50 or 100 mg.

MAIN OUTCOME MEASURE(S)

Primary outcome measures were safety, serum and urinary C-telopeptide (CTX), and serum ibandronate AUC0-infinity.

RESULTS

Once-monthly oral ibandronate was well tolerated, with a similar overall and upper gastrointestinal safety profile to placebo. Once-monthly ibandronate was also highly effective in decreasing bone turnover; substantial reductions from baseline in serum CTX (-56.7% and -40.7% in the 150- and 100-mg arms, respectively; P < 0.001 vs. placebo) and urinary CTX (-54.1% and -34.6%, respectively; P < 0.001 vs. placebo) were observed at d 91 (30 d after the final dose). Analysis of the area under the effect curve (d 1-91) for change from baseline (percent x days) in serum CTX and urinary CTX indicated a dose-response relationship. The AUC0-infinity for ibandronate increased with dose but not in a dose-proportional manner.

CONCLUSIONS

These findings indicate a potential role for once-monthly oral ibandronate in the treatment of postmenopausal osteoporosis.

The effect of calcitonin on biochemical markers and zinc excretion in postmenopausal osteoporosis

OBJECTIVES

A double-blind, randomized, placebo-controlled trial was conducted in women with postmenopausal osteoporosis to evaluate effects on biochemical markers and urinary excretion of zinc (Zn) of calcitonin therapy.

METHODS

Patients were required to have a bone mineral density (BMD) of 2.5 S.D. or more below the young adult mean either at the postero-anterior lumbar spine or at the femoral neck. Subjects were eligible for our study if they were 50 years or older, with at least 5 years of menopause, and in good general health as determined by medical history and a routine clinical blood analysis. The patients were randomly assigned to receive intranasal salmon calcitonin (200 IU/day; 50 patients) or placebo (50 patients). All patients received supplemental calcium (1000 mg/day). Additionally, 40 age-matched, demographically similar, healthy postmenopausal women were also selected as controls. Measurements of cross-linked N-telopeptides of type I collagen (uNTx), osteocalcin (sOC), and urinary zinc concentration were done. All parameters were measured before therapy and again after 1, 3 and 6 months.

RESULTS

After 3 and 6 months of treatment, a higher decrease of most indices was observed in the calcitonin group. A statistically significant decrease occurred in the levels of sOC, uNTx and uZn after 3 and 6 months in patients receiving calcitonin therapy (P<0.05). Levels of sOC and uNTx in calcitonin group were significantly different after 3 and 6 months from both placebo and baseline values of calcitonin group (P<0.05). Levels of sOC, uNTx and uZn decreased about 40, 46 and 37%, respectively, in calcitonin group at 6 months after the start of treatment.

CONCLUSIONS

Our study suggests that values of uNTx, uZn and sOC were significantly lower in the patient group than those in control group and in postmenopausal women with osteopororsis, calcitonin reduces the concentrations of uNTx, uZn and sOC.

Salmon calcitonin nasal spray treatment for postmenopausal women after hip fracture with total hip arthroplasty

The increasing rate of hip fractures is giving rise to a number of socioeconomic problems for the aging community. In addition to being unable to resume their previous living habits, many patients fail to achieve full functional recovery after the fractures. Total hip arthroplasty (THA) is a successful operation for the majority of patients with all forms of hip fractures. Dislocation and aseptic loosening are the major reasons for revisions. An additional problem post-THA is the rate of heterotopic soft tissue calcification after total hip arthroplasty, resulting in severely impaired function, pain, and a reduced range of hip motion. In an open study, 37 women who had undergone cementless total hip arthroplasty after accidental hip fractures were treated twice daily with 200 IU salmon calcitonin nasal spray for 12 months. Simultaneously, the patients received one bag of 1000 mg calcium plus 880 IU vitamin D daily throughout the treatment period of 1 year. A parallel group of 38 women with a similar clinical status in terms of hip fractures and cementless total hip arthroplasty were treated with only one bag of 1000 mg calcium plus 880 IU vitamin D daily through the treatment period. The results of this 12-month clinical trial show that 200 IU salmon calcitonin nasal spray per day promotes general independence from foreign assistance, mobility, and fear of further falls in postmenopausal elderly women following THA. Treatment with a salmon calcitonin nasal spray reduces bone turnover serum markers, loss of further bone density, and pain. Additionally, calcitonin promoted the repair of hip fractures and, as a coincidence finding, was associated with a significantly reduced rate of refractures as well as periprosthetic ossifications.

Is there a role for a random measurement of 24-hour urine calcium excretion in the determination of calcium supplementation in osteoporotic postmenopausal women using alendronate?

The article addresses the clinical query whether a casual determination of 24-hour urinary calcium excretion by the end of first-year treatment with alendronate in osteoporotic postmenopausal women correlates with the change in bone mineral density achieved during that year. The study included 2 arms: a prospective arm (n = 31) with women on long-term hormone replacement therapy were followed for 1 year after addition of alendronate (10 mg/daily); a retrospective arm (n = 33) with women using alendronate for 1 year. Bone mineral density and urine deoxypyridinoline were measured at baseline and 1 year, 24-hour urine calcium was obtained at 1 year. All patients used supplemental calcium, but the exact intake values were not determined. The results demonstrated no correlation between the annual increase in both spine and femur bone density and urinary calcium. Assuming that urinary calcium correlates with calcium intake and absorption, a casual measurement of urinary calcium excretion seems irrelevant for the titration of optimal calcium supplementation in this clinical setup.

Assessment of Urinary Bone Markers for Monitoring Treatment of Osteoporosis

Background: The usefulness of urinary markers of bone turnover in monitoring therapy depends on their within-person variability compared with their responses to therapy. The aim of this study was to assess the performance of two such markers on this basis.

Methods: We measured variation, during a whole year, of cross-linked N-terminal telopeptide of collagen I (NTx) and urinary deoxypyridinoline (DPD) as ratios to creatinine concentration and after log-transformation of the ratios in untreated women stratified into three bone density classes, of which the lowest was osteoporotic. We also measured changes in bone mineral density at the lumbar spine (LSBMD) and hip (FNBMD) in untreated women with normal bones and in those with moderate osteopenia and calculated the reference change value (RCV; or least significant change) at P &lt;0.05 for all of these measures. We made the same measurements on women treated with bisphosphonates, estrogen replacement (HRT), or calcium and examined their individual responses to treatment compared with RCV.

Results: After 12 months on bisphosphonates, LSBMD changed more than RCV (2.55%) in 47% of women compared with 44% of those on HRT and 13% of those on calcium. Response of FNBMD was less. Log NTx (RCV= −28%) responded to bisphosphonates in 78%, regardless of BMD, but less often to HRT (67%). Log DPD (RCV= −30%) responded to bisphosphonates less frequently (31% at 12 months).

Conclusions: NTx has advantages over DPD in monitoring therapy for osteoporosis when mailed urine samples are used.

A longitudinal evaluation of the effect of two doses of tibolone on bone density and metabolism in early postmenopausal women

Tibolone, a steroid with tissue-specific activities, can reduce the bone resorption that takes place after the menopause. The present calcium-controlled, 2-year study aimed to evaluate the effect of two doses of oral tibolone, 1.25 mg and 2.5 mg, on bone loss in early postmenopausal women. The subjects were randomly allocated to one of the three groups, namely tibolone 2.5 mg (n = 30), tibolone 1.25 mg (n = 30) and a control group (n = 30). All subjects received 1000 mg of calcium per day. In the control group, vertebral and femur bone mineral density (BMD) decreased significantly (p < 0.05) after 12 and 24 months. In both tibolone groups, vertebral and femur BMD increased significantly (p < 0.05) increased after 12 and 24 months. In the control group, bone turnover markers (urinary excretion of hydroxyproline/creatinine and plasma osteocalcin levels) remained constant, while in both tibolone groups these markers showed similar significant decreases (p < 0.05) after 12 and 24 months. After 24 months, body weight increased in the control group (p < 0.05), while smaller increments were evident in the tibolone groups. Symptom scores in the control group did not show any significant modification during the study. In contrast, the administration of 2.5 mg tibolone was significantly (p < 0.05) effective in reducing hot flushes and other symptoms. The tibolone 1.25 mg group yielded similar results (even if it was proportionally less efficient) to the higher dose. It is concluded that tibolone is effective, even at lower doses, in relieving climacteric symptoms and preventing a decrease in spine and femur BMD in early postmenopausal women.

The serum level of bone-specific alkaline phosphatase activity is associated with aortic calcification in osteoporosis patients

It has been suggested that there are several possible linkages between vascular calcification and osteoporosis. In addition, the processes of vascular calcification may have a common etiology with bone formation. Thus, we hypothesized that the serum levels of bone metabolic markers would be different between osteoporosis patients with and without vascular calcification. In this study, we showed that the serum level of bone-specific alkaline phosphatase activity in osteoporosis patients with abdominal aortic calcification had a higher value than in those without the calcification. On the other hand, there were no significant differences in the urine levels of type I collagen cross-linked N-telopeptides (a bone resorption marker), or in the serum levels of intact osteocalcin, Ca, and P. Bone-specific alkaline phosphatase is the most important marker for osteoblast differentiation; furthermore, the serum level of its activity may reflect the process of calcification of the aorta in osteoporosis patients.

The effects of soy protein containing isoflavones on lipids and indices of bone resorption in postmenopausal women

OBJECTIVE

To assess the effect of a dietary soy protein supplement containing isoflavones on lipids and indices of bone resorption in postmenopausal women.

DESIGN

Placebo-controlled, double-blind, randomized study.

PATIENTS

One hundred and six postmenopausal women were randomized to dietary soy supplementation (n = 51) or placebo (n = 55) for 3 months, of which 78 were included in the final analysis.

MEASUREMENTS

Lipid profiles including total, low-density lipoprotein (LDL) and HDL cholesterol as well as triacylglycerol were measured. Pyridinoline and deoxypyridinoline were used as markers of bone resorption. Urinary isoflavone excretion was measured to assess compliance.

RESULTS

There was a significantly greater increase in urinary isoflavone excretion detected in the soy group compared to placebo. Lipid profiles improved with significant decreases in LDL cholesterol (-0.60 +/- 0.10 vs.-0.29 +/- 0.09 mmol/l, P < 0.05), triacylglycerol (-0.22 +/- 0.07 vs. +0.01 +/- 0.05 mmol/l, P < 0.005) and the LDL : HDL ratio (-0.32 +/- 0.10 vs. +0.20 +/- 0.10, P < 0.005) in the soy group compared to placebo. There were no significant differences between the soy and placebo groups for urinary excretion of pyridinoline (-3.8 +/- 3.1 vs.-0.8 +/- 3.1 nmol/mmolCr, P = 0.4) or deoxypyridinoline (-0.8 +/- 0.9 vs.-0.3 +/- 0.7 nmol/mmolCr, P = 0.4).

CONCLUSIONS

In postmenopausal women, dietary supplementation with soy protein containing isoflavones does not appear to have oestrogenic effects on markers of bone resorption. Soy protein favourably affected lipids; however, these effects (fall in triacylglycerol and no change in HDL) differ from those observed with oral oestrogen. These findings suggest that soy may not have biologically significant oestrogenic effects on bone resorption and we hypothesize that the lipid effects may be mediated, at least in part, through nonoestrogenic mechanisms.

An immunoassay for type I collagen alpha 1 helicoidal peptide 620-633, a new marker of bone resorption in osteoporosis

Type I collagen fragments are the most sensitive markers of bone resorption in osteoporosis. Currently, all available type I collagen-related bone resorption markers detect in serum and/or urine fragments arising from the telopeptide region of the molecule. Our aim was to evaluate the technical and clinical performances of a new assay detecting in urine a degradation fragment originating from the helical part of type I collagen and consisting of the 620-633 sequence of the alpha1 chain. Urinary helical peptide was measured with a new ELISA (Metra Helical peptide, Quidel Corporation). Results were compared with those of urinary C-terminal cross-linking type I collagen of type I collagen (CTX), an established bone resorption marker. We measured urinary helical peptide levels in 89 healthy women (age 31-89 years) and in 59 postmenopausal women involved in two randomized studies of the efficacy of alendronate (10 mg/day; n = 20) and transdermal 17beta estradiol (50 microg/day; n = 39). The within-run and between-run CVs were < or = 7.3 and 8.7%, respectively. In 59 healthy women, urinary helical peptide levels highly correlated with those of urinary CTX (r = 0.78, P < 0.0001). The long-term intraindividual variability assessed over 6 months in 18 untreated postmenopausal women was 24%. Compared to 24 premenopausal women, urinary helical peptide was 42% (P < 0.0001) higher in 65 postmenopausal women (mean age, 60 years), an increase comparable to that of urinary CTX (+ 47%, P < 0.0001). Urinary helical peptide levels decreased by 72% (P < 0.0001) after 3 months of alendronate treatment and by 59% (P < 0.0001) after 6 months of transdermal estrogen therapy. These changes were of similar magnitude to those of urinary CTX (-69 and -62%, respectively; NS compared with changes in helical peptide). In women treated with transdermal 17beta estradiol, the percentage of change of urinary helical peptide and urinary CTX at 6 months significantly correlated with the change in spinal bone mineral density after 2 years (r = -0.58, P = 0.002, and r = -0.52, P = 0.006, for urinary helical peptide and CTX, respectively). This new assay for type I collagen helical peptide has demonstrated adequate analytical performance and was highly correlated with urinary CTX, an established type I collagen C-telopeptide bone resorption marker. The test was a sensitive indicator of the antiresorptive effects of bisphosphonate and estrogens in postmenopausal women. This new bone resorption marker should be useful for the clinical investigation of patients with osteoporosis.

Clinical usefulness of measurements of urinary deoxypyridinoline (DPD) in patients with postmenopausal osteoporosis receiving intermittent cyclical etidronate: advantage of free form of DPD over total DPD in predicting treatment efficacy

Deoxypyridinoline (DPD) in urine, which reflects systemic bone resorption, is considered useful for assessing the effects of osteoporosis treatment. However, there are various methods of measuring DPD in urine but have been few comparative studies of the effectiveness of these methods. In this study, we investigated 94 postmenopausal women (63 patients administered with intermittent cyclical etidronate (ICE), and 31 control patients) focusing on total DPD and free DPD, measured by high-performance liquid chromatography (HPLC) and enzyme-linked immunosorbent assay (ELISA), respectively. For other metabolic bone markers, i.e., tartrate-resistant acid phosphatase (TRAP), bone-specific alkaline phosphatase (BAP), and osteocalcin (OC), we also investigated the ability of these markers to predict increases in bone mineral density (BMD), by employing receiver operating characteristic (ROC) analysis in relation to increasing BMD following ICE therapy, and we determined the usefulness of the different metabolic bone markers, using the signal-noise ratio derived from the mean significant change (MSC), which is double the day-to-day coefficient of variation in healthy volunteers. In the same way, we defined a significant change in BMD as double the mean change in BMD for 6 months after the initiation of observation in the control group, and we used this value as the cutoff value for ROC analysis. It was found that the assessment of urinary DPD was useful for assessing the treatment efficacy of ICE, and the assessment of changes at week 12 of therapy was most effective. In order to recognize changes in metabolic bone markers when the MSC is considered as the cutoff value, it is useful to assess the change in total DPD by HPLC. However, in order to predict increases in BMD 6 months or more after the initiation of ICE, it seems more effective to measure free DPD by ELISA. We conclude, therefore, that the measurement of free DPD by ELISA is more useful, especially when treatment efficacy of ICE is clinically predicted in individual patients with osteoporosis.

Novel and traditional biomarkers of bone turnover in postmenopausal women

Urinary markers of bone collagen degradation such as N-terminal telopeptide, deoxypyridinoline, hydroxyproline and proline-hydroxyproline dipeptide as a novel marker were measured in both morning and daily urine samples collected from 40 postmenopausal women on 10 consecutive days. In addition, osteocalcin, bone alkaline phosphatase and procollagen C-terminal propeptide were analyzed in one serum sample from each of the women. DXA densitometry was employed to differentiate between osteopenic and osteoporotic women. Spearman rank correlation, factor analysis and receiver-operating characteristics were computed to evaluate the results. The highest correlation with a single common factor was found between telopeptide assayed in daily urine, followed by the dipeptide and hydroxyproline assayed in morning urine. These markers also showed high sensitivity for the diagnosis of osteoporosis, while osteocalcin had a high sensitivity for the diagnosis of bone disease. The concentrations of telopeptide, dipeptide and osteocalcin differed significantly between the osteopenic and osteoporotic subjects. Because of the ease of non-hydrolyzed urine processing, the speed of chromatographic analysis and the negligible costs, the dipeptide assay opens new possibilities in the field.

The values of urinary NTx in postmenopausal women undergoing HRT; the role of additional alendronate therapy

OBJECTIVE

To determine the changes in levels of urinary NTx at the end of the 6th month of oral and transdermal hormone replacement therapy (HRT) and the effects of additional alendronate therapy for osteoporotic women.

METHOD

Of 66 postmenopausal women 23 were treated with oral estradiol+norethisterone acetate (E+P), and 22 were treated with transdermal estradiol+norethisterone acetate. The third group consisted of 21 women with osteoporosis (bone mineral density < 100 mg/cm(3)) and treated with oral E+P plus alendronate 10 mg/day.

RESULT

Significant decreases of urinary NTx levels were seen after HRT in all study groups (P < 0.05). But the decline of NTx levels was not different between the oral and transdermal HRT groups (P > 0.05). There was no additional decrease in the levels of NTx with alendronate therapy (P > 0.05) but NTx excretion diminished more in patients with high baseline levels.

CONCLUSION

The decline of NTx at the end of the 6th month of HRT reflects the decrease of bone resorption and it is not related to the route of administration.

Type I collagen racemization and isomerization and the risk of fracture in postmenopausal women: the OFELY prospective study

The Asp1211 residue of the 1209AHDGGR1214 sequence of the C-terminal cross-linking telopeptide of type I collagen (CTX) can undergo spontaneous post-translational modifications, namely, racemization and isomerization, which result in the formation of four isomers: the native form (alpha-L) and three age-related forms, that is, an isomerized form (beta-L), a racemized form (alpha-D), and an isomerized/racemized (beta-D) form. Previous studies have suggested that changes in the pattern of type I collagen racemization/isomerization, which can be assessed in vivo by measuring the degradation products of the CTX isoforms, may be associated with alterations of bone structure. The aim of this study was to examine prospectively the value of the different urinary CTX isoforms and their related ratio in the prediction of osteoporotic fractures in 408 healthy untreated postmenopausal women aged 50-89 years (mean, 64 years) who were part of the OFELY cohort. During a median 6.8 years follow-up, 16 incident vertebral fractures and 55 peripheral fractures were recorded in 65 women. The baseline levels of the four CTX isoforms in women who subsequently had a fracture were compared with those of the 343 women who did not fracture. At baseline, women with fractures had increased levels of ratios of native alpha-L-CTX to age-related isoforms (beta-L, alpha-D, and beta-D) compared with controls (p < 0.01). In logistic regression analysis after adjustment for age, prevalent fractures, and physical activity, women with levels of alpha-L/beta-L, alpha-L/alpha-D, and alpha-L/beta-D-CTX ratios in the highest quartile had a 1.5- to 2-fold increased risk of fractures compared with women with levels in the three lowest quartiles with relative risk (RR) and 95% CI of 2.0 (1.2-3.5), 1.8 (1.02-2.7), and 1.5 (0.9-2.7), respectively. Adjustment of alpha-L/beta-L and alpha-L/alpha-D-CTX ratios by the level of bone turnover assessed by serum bone alkaline phosphatase (ALP)- or femoral neck bone mineral density (BMD) decreased slightly the RR, which remained significant for the alpha-L/beta-L-CTX ratio (RR [95%] CI, 1.8 [1.1-3.2] after adjustment for bone ALP, 1.8 [1.03-3.1] after adjustment for BMD, and 1.7 [0.95-2.9] after adjustment for both bone ALP and BMD). Women with both high alpha-L/beta-L-CTX ratio and high bone ALP had a 50% higher risk of fracture than women with either one of these two risk factors. Similarly, women with both increased CTX ratio and low femoral neck BMD (T score < -2.5) had a higher risk of fracture with an RR (95% CI) of 4.5 (2.0-10.1). In conclusion, increased urinary ratio between native and age-related forms of CTX, reflecting decreased degree of type I collagen racemization/isomerization, is associated with increased fracture risk independently of BMD and partly of bone turnover rate. This suggests that alterations of type I collagen isomerization/racemization that can be detected by changes in urinary CTX ratios may be associated with increased skeletal fragility.

Short-term effects of new synthetic conjugated estrogens on biochemical markers of bone turnover

Fifty early postmenopausal women completed a double-blind, placebo-controlled study evaluating the short-term effect of a new synthetic conjugated estrogens formulation (Cenestin) on bone turnover. Subjects were randomized to either 0.625 mg/day synthetic conjugated estrogens (n = 35) or placebo (n = 15) for 3 months. Biochemical markers were evaluated at baseline (three measurements at Days -2, -1, and 0) and Days 30, 60, and 90. Bone resorption assessed by urinary NTX (-31.4%) and serum CTX (-34.2%) was significantly (p < 0.01) decreased in the estrogen-treated group compared to the placebo group within 1 month of treatment. The mean percent decreases for urinary NTX from baseline during estrogen treatment were -58.0% (p < 0.01 vs. placebo) and -34.1% (ns) after 2 and 3 months, respectively. For serum CTX, the percent changes from baseline were -17.6% (p < 0.01) and -16.9% (p < 0.01) at 2 and 3 months, respectively. As expected, the decrease of both bone formation markers (bone ALP and PINP) was delayed compared to that of bone resorption and significant (p < 0.05-0.01) only after 2 months of treatment in the estrogen-treated group compared to the placebo group. Synthetic conjugated estrogens significantly decreased bone resorption and bone formation comparable to that previously reported for estrogen treatments proven efficacious in preventing postmenopausal bone loss.