Markers of bone resorption predict hip fracture in elderly women: the EPIDOS Prospective Study

The levels of bone turnover markers 25(OH)D and PTH and their relationship with bone mineral density in postmenopausal women in a suburban district in China

This study evaluated the levels of bone turnover markers (BTMs) and investigated relationships between them and bone mineral density (BMD) in postmenopausal women in China suburban district. The prevalence of osteoporosis was 25.03 % at lumbar spine and 6.23 % at femoral neck, and BTMs were negatively correlated with BMDs.

INTRODUCTION

The aims of this study were to evaluate the levels of bone turnover markers (BTMs), including serum N-terminal procollagen of type I collagen (P1NP), beta C-terminal cross-linked of type I collagen (β-CTX), 25-hydroxyvitamin D [25(OH)D], and parathyroid hormone (PTH), and to investigate relationships between these markers and bone mineral density (BMD) as well the prevalence of osteoporosis in postmenopausal women of suburban district.

METHODS

A population of 4822 postmenopausal women aged 55-69 years old (62.22 ± 6.75) from the suburban district was recruited voluntarily. BMD was measured at the lumbar spine, femoral neck, and total hip using dual-energy X-ray absorptiometry; 2251 women in this group had the serum BTMs 25(OH)D and PTH tested.

RESULTS

The prevalence of osteoporosis was 25.03 % at lumbar spine and 6.23 % at femoral neck. The median (interquartile range) values of serum P1NP, β-CTX, 25(OH)D, and PTH were 59.3 ng/mL (44.7-75.52), 0.370 ng/mL (0.280-0.490), 23.0 ng/mL (17.1-30.5), and 31.4 pg/mL (24.9-39.7), respectively. Serum P1NP and β-CTX levels presented significantly negative correlations with BMDs at the all the sites (Beta_std = -0.098 to -0.208, respectively, P < 0.001), whereas PTH levels were negatively correlated with BMDs of the femoral neck and total hip (Beta_std = -0.062 and -0.054, P < 0.01, respectively). Serum 25(OH)D had positive associations with BMDs at total hip (Beta_std = 0.051, P < 0.01).

CONCLUSIONS

The BMD of postmenopausal women in China suburban area is higher than that in downtown area, and over 60 % of the participants had their serum 25(OH)D level over 20 ng/mL. BTMs were negatively correlated with BMDs, suggesting that BTMs are reliable factors for early declines in BMD.

Bone Turnover Markers in the Diagnosis and Monitoring of Metabolic Bone Disease

BACKGROUND

Disorders of bone metabolism, most notably osteoporosis, are highly prevalent and predispose to fractures, causing high patient morbidity and mortality. Diagnosis and monitoring of bone metabolic defects can present a major challenge as these disorders are largely asymptomatic and radiographic measures of bone mass respond slowly to changes in bone physiology.

CONTENT

Bone turnover markers (BTMs) are a series of protein or protein derivative biomarkers released during bone remodeling by osteoblasts or osteoclasts. BTMs can offer prognostic information on fracture risk that supplements radiographic measures of bone mass, but testing using BTMs has to take into account the large number of preanalytic factors and comorbid clinical conditions influencing BTM levels. BTMs respond rapidly to changes in bone physiology, therefore, they have utility in determining patient response to and compliance with therapies for osteoporosis.

SUMMARY

BTMs are a useful adjunct for the diagnosis and therapeutic monitoring of bone metabolic disorders, but their use has to be tempered by the known limitations in their clinical utility and preanalytic variables complicating interpretation.

Effect of self-reported walking difficulty on bone mass and bone resorption marker in Japanese people aged 40 years and over

Background

This study aimed to examine the association of walking difficulty with bone mass or bone turnover among community-dwelling Japanese people aged 40 years and older.

Methods

We studied 1097 community-dwelling Japanese people aged 40 years and older (379 men and 718 women) who were invited to participate in periodic health examinations in 2006–2009. Walking difficulty was defined as having difficulty walking 100 m on a level surface (self-administered questionnaire). Calcaneal stiffness index (bone mass) was measured by quantitative ultrasound. Spot urine samples were collected, and urinary N-terminal cross-linking telopeptide of type I collagen (NTx) was measured. Values were corrected for creatinine (Cre) concentration.

Results

The prevalence of walking difficulty was significantly higher in women than in men (7.4 vs. 3.4 %, p = 0.011) and significantly increased with age in men (p for trend = 0.02) and women (p for trend <0.001). In univariate analysis, men and women with walking difficulty were older (p < 0.001) and had a lower stiffness index (p < 0.001), compared with those without walking difficulty. Among women, individuals with walking difficulty had significantly higher urinary NTx/Cre than those without walking difficulty (p < 0.001); however, this was not so among men (p = 0.39). Multiple regression analysis adjusted for age, weight, and menopausal status showed a significant association between walking difficulty and lower stiffness index in men (p = 0.004) and women (p = 0.005). In women, walking difficulty was significantly associated with higher NTx/Cre (p = 0.001), but not in men (p = 0.35).

Conclusions

Walking difficulty may contribute to low bone mass in both sexes but might cause high bone turnover in women only.

Biochemical Markers of Bone Turnover and Fracture Prediction

Low bone mineral density is a strong risk factor for fractures in the older woman. Biochemical markers of bone turnover may predict fracture risk independently of bone mineral density. High levels of bone resorption markers are associated with increased risk of fracture in both retrospective and prospective studies, although the evidence for bone formation markers and fracture risk is equivocal. For example, the risk of fracture is increased up to two-fold in women with elevated levels of several markers of bone resorption. Prediction models have been developed to predict the 10–year risk of fracture using bone mineral density and biochemical markers of bone turnover and these could prove very useful in clinical practice.

Safety and pharmacodynamic dose response of short-term prednisone in healthy adult subjects: a dose ranging, randomized, placebo-controlled, crossover study

Background

Glucocorticoids (GCs), such as prednisone, are the standard of care for several inflammatory and immunologically mediated diseases, but their chronic systemic administration is severely limited by serious adverse effects that are both dose and time dependent. Short-term treatment (7–14 days) with oral prednisone is used for many acute inflammatory and allergic conditions. This study was conducted to characterize the safety and pharmacodynamic (PD) dose–response of a 7-day course of oral prednisone on biomarkers of GC receptor agonism.

Methods

In this randomized, single-blind, placebo-controlled, crossover study (A9001309), 37 healthy subjects received placebo or a prednisone dose from 2.5–60 mg daily over 7 days in each of three treatment periods. White blood cell counts and plasma samples for measuring cortisol, osteocalcin and procollagen type 1 N-propeptide (P1NP) were obtained at 2, 4, 8, and 12 h post-dose on Day 1, immediately prior to dosing on Days 1, 2, and 4, and at nominal dosing time on Days 0 and 8. Urine samples for urinary N-terminal cross-linked telopeptide of type 1 collagen (uNTX) were collected on Days 0, 1, 2, 4, and 8. Serum samples for adiponectin were obtained prior to dosing on days 0, 1, 4 and 8.

Results

Daily doses of prednisone up to 60 mg resulted in dose- and time-dependent decreases in plasma osteocalcin, plasma P1NP, serum cortisol, and absolute blood eosinophil counts. Absolute blood neutrophil counts increased, while blood lymphocyte counts rebounded to an increased level following an initial rapid decrease after dosing. An increase was observed for uNTX and adiponectin. The incidence of adverse effects with prednisone was not dose related, and nervous system disorders, mainly headache, were the most frequently reported adverse effects.

Conclusions

This characterization provides important and relevant information on safety and PD responses of short-term prednisone dosing over the commonly-used clinical dose range, and also provides a reference for early clinical development of dissociated agents targeting a differentiated PD profile.

Trial registration number

NCT02767089 (retrospectively registered: 21 April 2016).

Increased Bone Resorption: A Possible Pathophysiological Link Between Hypovitaminosis D and Peripheral Arterial Disease

OBJECTIVE/BACKGROUND

Vitamin D deficiency has been associated with the prevalence and severity of peripheral arterial disease (PAD); nevertheless, data on bone turnover in patients with PAD is lacking. The present study investigates a possible relationship between the markers of bone turnover and the presence and severity of PAD.

METHODS

The study examined 143 patients, with a mean ± SD age of 75.3 ± 8.5 years (range 50.0-93.0 years), of both sexes, admitted to a department of internal medicine. All patients underwent ankle brachial index (ABI) assessment by Doppler velocimetry. Serum levels of 25(OH) vitamin D and two markers of bone turnover, C-terminal telopeptide of type I collagen (sCTX) and bone isoenzyme of alkaline phosphatase, were measured. The differences between patients with normal ABI and patients with PAD were analyzed. Pearson and Spearman correlation coefficients were calculated and independent predictors were identified through a stepwise linear regression analysis. Odds ratios were calculated with a logistic regression model.

RESULTS

Compared with patients with a normal ABI (≥0.90), patients with PAD (ABI < 0.90) presented with significantly lower levels of 25(OH) vitamin D (12.2 ± 9.6 ng/mL vs. 16.7 ± 8.7 ng/mL; p = .006) and a significantly higher concentration of sCTX (1.1 ± 0.7 ng/mL vs. 0.6 ± 0.4 ng/mL; p < .001). There was a positive correlation between ABI and serum concentration of 25 (OH) vitamin D (r = 0.3; p < .001), whereas ABI was inversely correlated with the concentration of sCTX (r = -0.358; p < .001). At logistic regression analysis, age, cigarette smoking, and both vitamin D and sCTX were independent predictors of an ABI < 0.90.

CONCLUSION

These results support the hypothesis that hypovitaminosis D and increased bone turnover are risk factors for the presence and severity of PAD. Furthermore, the presence of PAD, even if asymptomatic and diagnosed by a reduced ABI, could identify a population at risk for osteoporosis and osteomalacia.

Quantifying the Balance Between Total Bone Formation and Total Bone Resorption: An Index of Net Bone Formation

CONTEXT

Bone gain vs loss across the skeleton loss depends on the balance between total bone formation and total bone resorption.

OBJECTIVE

The objective of the study was to determine whether resorption and formation markers can be combined to gauge net bone formation across the skeleton.

DESIGN

The study included a cohort followed up across menopause transition (Study of Women's Health Across the Nation).

SETTING AND PARTICIPANTS

Community-dwelling women, 42-52 years old, premenopausal or early perimenopausal at baseline, participated in the study.

OUTCOME

The study included the following measures: 1) bone balance index (BBI) created by estimating the relationship between resorption (urinary N-telopeptide) and formation (osteocalcin) markers when the total formation equals the total resorption in 685 women with stable bone mineral density (BMD) (>5 y before the final menstrual period [FMP]) and applying this relationship to measured bone turnover markers in 216 women beginning to lose bone (≤2 y from FMP); and 2) annualized percentage declines over the following 3-4 years in the lumbar spine (LS) and femoral neck (FN) BMD.

RESULTS

Adjusted for covariates, the BBI was greater (more favorable) in women with a greater body mass index (P = .03) and lower (less favorable) in women closer to the FMP (P = .007). Each SD decrement in BBI was associated with 0.27%/y faster LS BMD decline (P 0.04) and a 38% higher odds of faster-than-average loss of LS bone mass (P = .008, c-statistic 0.76). BBI was not associated with decline in FN BMD. Urinary N-telopeptide alone was not associated with either LS or FN BMD decline.

CONCLUSIONS

An index that quantifies net bone formation vs resorption can be created from bone turnover markers and may help identify individuals at high risk for LS bone loss.

Preliminary Report on the Investigation of the Association Between BPPV and Osteoporosis Using Biomarkers

OBJECTIVE

To test the hypothesis that levels of a BPPV biomarker, otolin-1, correlate with those of osteoporosis markers, aminoterminal propeptide of protocollagen type I (P1NP), and aminoterminal telopeptides of collagen (NTX), thus further supporting a link between the two diseases.

STUDY DESIGN

Prospective pilot clinical trial (Level of Evidence: 2b).

PATIENTS

Postmenopausal women with BPPV.

INTERVENTIONS

Diagnostic.

MAIN OUTCOME MEASURES

Serum levels of otolin-1, P1NP, NTX, vitamin D, and calcium were examined in relation to each other, age, and DEXA scan T-scores.

RESULTS

There was a strong, negative correlation between T-scores and otolin-1 levels. Although P1NP and NTX levels were strongly correlated, neither had statistical correlations with otolin-1.

CONCLUSIONS

Despite a strong correlation between DEXA scan results and otolin-1 levels, there were no significant correlations between otolin-1 and P1NP or NTX. This suggests that the association between osteoporosis and BPPV is complex, but not likely to be causal. Although more work is needed to elucidate these relationships, this preliminary finding has important practical implications for BPPV in that proactive management of osteoporosis, per se, would not be expected to have benefits in management of BPPV.

Soluble CD14 and fracture risk

Soluble CD14 (sCD14) is an inflammatory marker associated with osteoclasts. Using Cox proportional hazards models, we found a positive association between plasma levels of sCD14 and risk of incident fracture among participants in the Cardiovascular Health Study. sCD14 may be useful in identifying those at risk for fracture.

INTRODUCTION

Soluble CD14, a proinflammatory cytokine, is primarily derived from macrophages/monocytes that can differentiate into osteoclasts. The purpose of this study was to examine the relationship between sCD14 levels and osteoporotic fractures.

METHODS

In the Cardiovascular Health Study, 5462 men and women had sCD14 levels measured at baseline. Incident hip fractures (median follow-up time 12.5 years) and incident composite fractures (defined as the first hip, pelvis, humerus, or distal radius fracture, median follow-up 8.6 years) were identified from hospital discharge summaries and/or Medicare claims data. Cox proportional hazards models were used to model the association between sCD14 levels and time to incident hip or composite fracture, overall and as a function of race and gender.

RESULTS

In unadjusted models, there was a positive association between sCD14 levels (per 1 standard deviation increase, i.e., 361.6 ng/mL) and incident hip (HR, 1.26; 95 % CI, 1.17, 1.36) and composite (HR, 1.20; 95 % CI, 1.12, 1.28) fractures. When models were fully adjusted for demographics, lifestyle factors, and medication use, these associations were no longer significant. However, in whites, the association of sCD14 levels with hip fractures remained significant in fully adjusted models (HR, 1.11; 95 % CI, 1.01-1.23). Associations of sCD14 levels with hip and composite fracture did not differ between men and women.

CONCLUSIONS

In this large cohort of community-dwelling older adults, higher sCD14 levels were associated with an increased risk of incident hip fractures in whites.

The use of biochemical markers of bone turnover in the clinical management of primary and secondary osteoporosis

The purpose of the present study was to examine of the current role of bone turnover markers (BTMs) in the management of osteoporosis. Perusal of the literature examines the available evidence for the utility of BTMs for decision to treat and for the monitoring of treatment for osteoporosis. There is no evidence for the use of BTMs for fracture risk calculation, decision to treat or for treatment selection. A very abnormal BTM value may be a clue to the presence of bone pathology other than uncomplicated osteoporosis. Whilst changes to BTMs following various osteoporosis treatments are well defined, their utility in monitoring individual patients has been less well established. Some fracture outcome-based data exist for the use of u-NTX target of <21 nmol BCE/mmol for antiresorptive therapy; the equivalent s-CTX level is ~250 ng/L. Suboptimal BTM response to treatment may indicate non-compliance or the presence of secondary causes of osteoporosis which may need addressing. Studies are needed to establish treatment targets based on fracture outcomes for commonly used BTMs for each established osteoporosis therapy.

Biomarkers in axial spondyloarthritis

PURPOSE OF REVIEW

To assess the literature for biomarker validation studies that address key unmet needs related to the evaluation and management of patients with axial spondyloarthritis (SpA). This review focused on biomarkers facilitating early diagnosis and reflecting disease activity, structural damage on radiography, and clinical response to major therapies.

RECENT FINDINGS

Early diagnosis may be facilitated by measurement of antibodies to the human leukocyte antigen class II-associated invariant chain peptide (anti-CD74) but sensitivity declines with increasing duration of disease. No disease activity biomarkers have demonstrated consistent superiority over standard C-reactive protein (CRP), and future validation should employ multivariate analysis aimed at demonstrating the added value of any associated biomarkers beyond available clinical parameters of disease activity and the use of magnetic resonance imaging inflammation as the primary endpoint. Several biomarkers reflecting inflammation (CRP and calprotectin), angiogenesis (vasoactive endothelial growth factor), and connective tissue turnover (C2 M, C3 M, and citrullinated metalloproteinase degraded fragment of vimentin ) have recently been shown to reflect radiographic progression in multivariate studies adjusted for baseline severity. Future studies should be prospective and demonstrate that predictive capacity adds to the information provided by known predictors such as CRP and baseline modified Stoke AS Spine Score. Calprotectin is a promising predictor of response to major therapies for axial SpA.

SUMMARY

Several promising biomarkers addressing major unmet clinical needs require further validation in prospective studies.

Bone turnover biomarkers and risk of osteoporotic hip fracture in an Asian population

While epidemiologic studies suggest that bone turnover biomarkers may predict hip fracture risk, findings are inconsistent and Asian data are lacking. We conducted a matched case-control (1:1) study nested in the Singapore Chinese Health Study, a population-based prospective cohort of Chinese men and women (45-74years) recruited from 1993 to 1998 in Singapore. One hundred cases with incident hip fracture and 100 individually matched controls were randomly selected from 63,257 participants. Serum bone turnover biomarkers, namely bone alkaline phosphatase (bone ALP), osteocalcin (OC), procollagen type I N propeptide (PINP), N-terminal and C-terminal crosslinking telopeptide of type I collagen (NTX-I and CTX-I) were measured using immunoassays. Hip fracture cases had significantly higher serum levels of OC, PINP, CTX-I and NTX-I than controls (p<0.05). There was a dose-dependent positive relationship between OC, PINP, CTX-I and NTX-I and risk of hip fracture (all Ps for trend≤0.006), where the risk was significantly increased by 4.32-8.23 folds for the respective BTM [Quartile (Q) 4 vs. Q1]. The odds ratio [OR (95% CI)] at the highest quartile (Q4) was 6.63 (2.02-21.18) for PINP and 4.92 (1.67-14.51) for CTX-I. The joint effect of PINP and CTX-I showed a 7-fold increase in risk (OR: 7.36; 95% CI: 2.53-21.41) comparing participants with higher levels of PINP (Q4) and CTX-I (Q3-Q4) to those with low levels of PINP (Q1-Q3) and CTX-I (Q1-Q2). Our data demonstrated that higher serum levels of bone turnover biomarkers were associated with increased risk of hip fracture in an Asian population.

Treatment of osteoporosis after alendronate or risedronate

Alendronate (ALN) and risedronate (RIS) are ideal as first-choice therapy options in the treatment of postmenopausal osteoporosis. What to do for patients who do not respond adequately to bisphosphonates has not been conclusively determined, but transitioning to other therapies should be considered. The aim of this article is to describe potential alternatives for patients switching from ALN or RIS to other therapies for osteoporosis. A systematic search of PubMed was conducted to find papers that evaluate the effects of switching therapies on fractures, bone mineral density (BMD), or bone turnover markers. Results from 11 studies that prospectively assessed treatment after ALN or RIS in women with postmenopausal osteoporosis were reviewed. All studies are of short duration (all 24 months or less) and assess the topic of transitioning therapy from ALN or RIS. None of the studies had the statistical power to assess fracture-reduction efficacy. Transitioning from ALN to zoledronic acid maintains therapeutic effects for 12 months. Switching to strontium ranelate, denosumab, or teriparatide causes further increases in BMD. Specifically, transitioning to teriparatide could be used for a limited time for select patients but needs to be followed up with anti-resorptive treatment to prevent a loss of the bone gained. There are only few studies-of short duration-that assess the topic of transitioning therapy from ALN or RIS, although this is a very frequent occurrence in clinical practice. This is especially true if the patient has not reached his/her therapy goal. Further long-term studies are needed.

Managing Osteoporosis in Patients on Long-Term Bisphosphonate Treatment: Report of a Task Force of the American Society for Bone and Mineral Research

Bisphosphonates (BPs) are the most commonly used medications for osteoporosis. This ASBMR report provides guidance on BP therapy duration with a risk-benefit perspective. Two trials provided evidence for long-term BP use. In the Fracture Intervention Trial Long-term Extension (FLEX), postmenopausal women receiving alendronate for 10 years had fewer clinical vertebral fractures than those switched to placebo after 5 years. In the HORIZON extension, women who received 6 annual infusions of zoledronic acid had fewer morphometric vertebral fractures compared with those switched to placebo after 3 years. Low hip T-score, between -2 and -2.5 in FLEX and below -2.5 in HORIZON extension, predicted a beneficial response to continued therapy. Hence, the Task Force suggests that after 5 years of oral BP or 3 years of intravenous BP, reassessment of risk should be considered. In women at high risk, for example, older women, those with a low hip T-score or high fracture risk score, those with previous major osteoporotic fracture, or who fracture on therapy, continuation of treatment for up to 10 years (oral) or 6 years (intravenous), with periodic evaluation, should be considered. The risk of atypical femoral fracture, but not osteonecrosis of the jaw, clearly increases with BP therapy duration, but such rare events are outweighed by vertebral fracture risk reduction in high-risk patients. For women not at high fracture risk after 3 to 5 years of BP treatment, a drug holiday of 2 to 3 years can be considered. The suggested approach for long-term BP use is based on limited evidence, only for vertebral fracture reduction, in mostly white postmenopausal women, and does not replace the need for clinical judgment. It may be applicable to men and patients with glucocorticoid-induced osteoporosis, with some adaptations. It is unlikely that future trials will provide data for formulating definitive recommendations. © 2015 American Society for Bone and Mineral Research.

Are Biochemical Markers of Bone Turnover Representative of Bone Histomorphometry in 370 Postmenopausal Women?

CONTEXT

The levels of bone formation and resorption can be assessed at the tissue level by bone histomorphometry on transiliac bone biopsies. Systemic biochemical markers of bone turnover reflect the overall bone formation and resorption at the level of the entire skeleton but cannot discriminate the different skeletal compartments.

OBJECTIVE

Our aim was to investigate the correlations between the serum biochemical markers of formation and resorption with histomorphometric parameters.

DESIGN

We performed post hoc analysis of a previous clinical study.

SETTING

Patients were selected from the general population.

PATIENTS

A total of 371 untreated postmenopausal osteoporotic women aged 50 to 84 years with a lumbar T-score ≤ -2.5 SD or ≤ -1 SD with at least one osteoporotic fracture.

INTERVENTIONS

Transiliac bone biopsies were obtained after a double tetracycline labeling, and blood samples were collected.

MAIN OUTCOME MEASURES

The static and dynamic parameters of formation and bone resorption were measured by histomorphometry. Serum biochemical markers of formation (bone alkaline phosphatase [ALP]; procollagen type I N-terminal propeptide [PINP]) and resorption (C-terminal crosslinking telopeptide of collagen type 1 [sCTX]) were assessed.

RESULTS

The mean values of biochemical markers were: bone ALP, 15.0 ± 5.2 ng/mL; PINP, 56.2 ± 21.9 μg/mL; and sCTX, 0.58 ± 0.26 ng/mL. Bone ALP and PINP were significantly correlated with both the static and dynamic parameters of formation (0.21 ≤ r' ≤ 0.36; 0.01 ≥ P ≥ .0001). sCTX was significantly correlated with all resorption parameters (0.18 ≤ r' ≤ 0.24; 0.02 ≥ P ≥ .0001).

CONCLUSION

Bone turnover markers were significantly but modestly associated with bone turnover parameters measured in iliac cancellous bone. The iliac crest bone may not represent perfectly the whole bone turnover.

Bone turnover markers are associated with higher cortical porosity, thinner cortices, and larger size of the proximal femur and non-vertebral fractures

Bone turnover markers (BTM) predict bone loss and fragility fracture. Although cortical porosity and cortical thinning are important determinants of bone strength, the relationship between BTM and cortical porosity has, however, remained elusive. We therefore wanted to examine the relationship of BTM with cortical porosity and risk of non-vertebral fracture. In 211 postmenopausal women aged 54-94 years with non-vertebral fractures and 232 age-matched fracture-free controls from the Tromsø Study, Norway, we quantified femoral neck areal bone mineral density (FN aBMD), femoral subtrochanteric bone architecture, and assessed serum levels of procollagen type I N-terminal propeptide (PINP) and C-terminal cross-linking telopeptide of type I collagen (CTX). Fracture cases exhibited higher PINP and CTX levels, lower FN aBMD, larger total and medullary cross-sectional area (CSA), thinner cortices, and higher cortical porosity of the femoral subtrochanter than controls (p≤0.01). Each SD increment in PINP and CTX was associated with 0.21-0.26 SD lower total volumetric BMD, 0.10-0.14 SD larger total CSA, 0.14-0.18 SD larger medullary CSA, 0.13-0.18 SD thinner cortices, and 0.27-0.33 SD higher porosity of the total cortex, compact cortex, and transitional zone (all p≤0.01). Moreover, each SD of higher PINP and CTX was associated with increased odds for fracture after adjustment for age, height, and weight (ORs 1.49; 95% CI, 1.20-1.85 and OR 1.22; 95% CI, 1.00-1.49, both p<0.05). PINP, but not CTX, remained associated with fracture after accounting for FN aBMD, cortical porosity or cortical thickness (OR ranging from 1.31 to 1.39, p ranging from 0.005 to 0.028). In summary, increased BTM levels are associated with higher cortical porosity, thinner cortices, larger bone size and higher odds for fracture. We infer that this is produced by increased periosteal apposition, intracortical and endocortical remodeling; and that these changes in bone architecture are predisposing to fracture.

Osteoprotective effects of estrogen membrane receptor GPR30 in ovariectomized rats

G protein-coupled estrogen receptor 30 (GPR30) is expressed in bone tissue. However, little is known regarding the function of GPR30 in postmenopausal osteoporosis. In this study, we examined the effects of GPR30 on ovariectomy (OVX)-induced osteoporosis in rats, including the effects on proliferation, differentiation, and expression of proteins in osteoblasts. Administration of G1 (35 μg/kg, ip, 3 times/week for 6 weeks), a specific agonist of GPR30, prevented OVX-induced increase in bone turnover rate, decrease in bone mineral content and bone mineral density, damage to bone structure, and aggravation of bone biomechanical properties. In addition, G1 did not affect uterine weight in the OVX rats. Osteoblasts isolated from calvarias from newborn rats were used to explore the underlying mechanisms. G1 (150 pM) promoted proliferation and differentiation of osteoblasts through a positive feedback of GPR30, which then activated the PI3K-Akt, ERK, and CREB pathways. G15 (750 pM), a specific antagonist of GPR30, reversed the above effects initiated by G1 treatment. In conclusion, activation of GPR30 protected bones against osteoporosis in OVX rats and exerted no untoward effect on the uterus. We suggest that GPR30 can be used as an effective therapeutic target for the prevention and treatment of postmenopausal osteoporosis.

25-Hydroxyvitamin-D and Bone Turnover Marker Levels in Patients with Distal Radial Fracture

BACKGROUND

Fragility fractures are a major public health issue with substantial socioeconomic cost. Vitamin-D deficiency and increased bone turnover are associated with higher rates of bone loss and an increased risk of fracture. We hypothesized that patients with a distal radial fracture would have lower levels of 25-hydroxyvitamin D (25[OH]D) and increased levels of serum bone turnover markers than controls without a fracture.

METHODS

Postmenopausal women with a recent distal radial fracture (fracture group, n = 105) were prospectively recruited and were compared with individuals without a fracture (control group, n = 150). Outcome variables included serum levels of 25(OH)D and markers of bone formation, including N-terminal extension propeptide of type-I collagen (P1NP), parathyroid hormone (PTH), bone-specific alkaline phosphatase (BSAP), and osteocalcin, as well as a marker of resorption (C-terminal telopeptide of type-I collagen [CTX-1]). Bone mineral density was measured with dual x-ray absorptiometry.

RESULTS

The fracture group was slightly older than the control group (mean and standard deviation [SD], 66.8 ± 10.8 years versus 63.3 ± 9.0 years, p = 0.008), had a lower body mass index (26.4 ± 5.9 kg/m(2) versus 28.0 ± 6.2 kg/m(2), p = 0.05), and more commonly had had a prior fracture (52% versus 31%, p < 0.001). Bone mineral density at the hip was lower in the fracture group than in the control group (0.831 ± 0.130 g/cm(2) versus 0.917 ± 0.139 g/cm(2), p < 0.001). The mean 25(OH)D levels were similar in the fracture and control groups (44.4 ± 14.6 ng/mL versus 41.3 ± 14.5 ng/mL, p = 0.08). Levels of serum markers of bone formation were significantly higher in the fracture group than in the control group (P1NP: 70.4 ± 33.2 ng/mL versus 53.2 ± 25.6 ng/mL, p < 0.001; osteocalcin: 22.3 ± 9.9 ng/mL versus 20.2 ± 9.2 ng/mL, p = 0.017). Levels of BSAP, PTH, and CTX-1 were similar in the two groups. Multivariable logistic regression showed independent associations between a distal radial fracture and low total hip bone mineral density (odds ratio [OR] = 2.02 for each decrease of 1 SD, 95% confidence interval [CI] = 1.38 to 3.01, p < 0.001) and a high P1NP level (OR = 2.17 for each 1-SD increase, 95% CI = 1.52 to 3.06, p < 0.001).

CONCLUSIONS

In this cohort, 25(OH)D levels were not associated with distal radial fracture and do not appear to affect the risk assessment for distal radial fracture in postmenopausal women. Patients with a distal radial fracture, however, had increased bone turnover as evidenced by high P1NP and osteocalcin levels. Women with both a high P1NP level and low bone mineral density were at particularly high risk for fracture.

Prediction of fracture risk in patients with osteoporosis: a brief review

Osteoporosis, a well-defined and growing public health problem, is a disease characterized by increased bone turnover and decreased bone mass with associated skeletal fragility, resulting in an increased risk of fracture. It is often unrecognized until the late stages when fragility fractures have occurred. In adults, early recognition of the disease prior to the occurrence of fractures followed by timely and efficient initiation of appropriate treatment can reduce fracture risk. In this article, we review clinical modalities available to effectively predict fracture risk in patients with osteoporosis. Bone mineral density and presence of clinical risk factors may be combined to provide a more comprehensive osteoporotic fracture risk assessment. Use of FRAX may serve as a general guideline for clinical management and deciding a threshold for cost-effective pharmacological intervention. Elevated bone turnover markers are predictive of high fracture risk and can provide additional clinical information as well.

Osteoprotective effect of combination therapy of low-dose oestradiol with G15, a specific antagonist of GPR30/GPER in ovariectomy-induced osteoporotic rats

Administration of low-dose oestradiol (E2) combining G15, this combination therapy may be an effective supplement of drugs in prevention and treatment for postmenopausal osteoporosis.

Identified and cloned in 1996 for the first time, G protein-coupled oestrogen receptor (ER) 30 (GPR30/GPER) has been a hot spot in the field of sex hormone research till now. In the present study, we examined the effects of low-dose oestradiol (E2) combined with G15, a specific antagonist of GPR30 on ovariectomy (OVX)-induced osteoporosis in rats. Female Sprague–Dawley (SD) rats undergoing OVX were used to evaluate the osteoprotective effect of the drugs. Administration of E2 [35 μg/kg, intraperitoneally (ip), three times/week) combining G15 (160 μg/kg, ip, three times/week) for 6 weeks was found to have prevented OVX-induced effects, including increase in bone turnover rate, decrease in bone mineral content (BMC) and bone mineral density (BMD), damage of bone structure and the aggravation in biomechanical properties of bone. The therapeutic effect of these two drugs in combination was better than that of E2 alone. Meanwhile, the administration of G15 prevented body weight increase or endometrium proliferation in the rats. In conclusion, administration of low-dose E2 combining G15 had a satisfactory bone protective effect for OVX rats, without significant influence on body weight or the uterus. This combination therapy may be an effective supplement of drugs in prevention and treatment for postmenopausal osteoporosis.

Associations between frailty and serum N-terminal propeptide of type I procollagen and 25-hydroxyvitamin D in older Spanish women: The Toledo Study for Healthy Aging

Frail older people are at high risk for fractures and falls increasing the rates of institutionalization and mortality. Bone markers have been related to both aging and fractures. However, no previous reports have shown a potential relationship between serum bone markers such as N-terminal propeptide of type I procollagen (PINP), C-terminal telopeptide of type I collagen (β-CTX) and parathyroid hormone (PTH) with frailty in elderly female populations. This study is aimed at examining the associations of bone metabolism markers and frailty in older Spanish women through a descriptive cross-sectional analysis based on a cohort of the Toledo Study for Healthy Aging (TSHA). The levels of serum PINP, β-CTX, PTH and 25-hydroxyvitamin D (25(OH)D) were assessed in 592 participants (median age 74years) who were defined as robust, prefrail and frail according to Fried's approach. Frail subjects had significantly high levels of PINP, β-CTX and PTH and low production of 25(OH)D. After adjustment for confounders, high PINP levels (defined by the upper quartile) and low levels of 25(OH)D (lower quartile) remained significantly associated to frailty [OR for PINP: 2.19 (95% CI, 1.15-4.18; P=0.017); OR for 25(OH)D: 1.65 (95% CI, 1.02-2.67; P=0.042)]. Women with both high PINP levels and low 25(OH)D levels presented a 5.85-fold increased frailty risk (95% CI, 1.64-20.93; P=0.007). The main contribution of this paper is the novel definition of PINP and 25(OH)D markers as potential biomarkers of frailty and targets for intervention.

Evaluation of a topical herbal agent for the promotion of bone healing

A topically used Chinese herbal paste, namely, CDNR, was designed to facilitate fracture healing which is usually not addressed in general hospital care. From our in vitro studies, CDNR significantly inhibited the release of nitric oxide from RAW264.7 cells by 51 to 77%. This indicated its anti-inflammatory effect. CDNR also promoted the growth of bone cells by stimulating the proliferation of UMR106 cells up to 18%. It also increased the biomechanical strength of the healing bone in a drill-hole defect rat model by 16.5% significantly. This result revealed its in vivo efficacy on facilitation of bone healing. Furthermore, the detection of the chemical markers of CDNR in the skin and muscle of the treatment area demonstrated its transdermal properties. However, CDNR did not affect the bone turnover markers in serum of the rats. With its anti-inflammatory and bone formation properties, CDNR is found effective in promoting bone healing.

Predictors of re-fracture amongst patients managed within a secondary fracture prevention program: a 7-year prospective study

SUMMARY

This 7-year prospective observational study determined the predictors of re-fracture amongst 234 patients managed within a Secondary Fracture Prevention programme. Poor compliance, multiple co-morbidities, corticosteroid therapy, low hip bone mineral density (BMD) or low body weight were all significantly associated with re-fracture in patients commenced on long-term anti-resorptive therapy.

INTRODUCTION

Risk factors for osteoporotic fracture amongst treatment-naïve patients are well established. In contrast, predictors of re-fracture in patients optimally managed within a Secondary Fracture Prevention (SFP) programme are ill-defined.

METHODS

This prospective observational study included 234 subjects with incident osteoporotic fractures managed long-term by the Concord SFP programme. Using Cox proportional hazards models, predictors of re-fracture were analysed separately for patients commenced on specific pharmacotherapy (group 1, N=171) and subjects receiving calcium and/or vitamin D supplements only (group 2, N=63). Relevant anthropometric, clinical and technical data were documented at each visit. Compliance and persistence were analysed as time-varying covariates.

RESULTS

During a mean follow-up of 5.2 (range 3.5-7.3) years, 20.9% of all subjects re-fractured (26.3% in group 1, 6.3% in group 2). Multivariate predictors of re-fracture in group 1 were significant co-morbidity (HR 2.04 if >3, 95% CI 1.10-3.79, p=0.024), corticosteroid use (HR 1.75, 95% CI 1.12-2.73, p=0.013) and total hip BMD (HR 1.36 per 0.1 g/cm2 decrease, 95% CI 1.08-1.70, p=0.008). In contrast, gender, prevalent fractures and lumbar spine BMD were not associated with re-fracture. Amongst patients with complete compliance data, a medication possession ratio of ≤50% (HR 3.36, 95% CI 1.32-8.53, p=0.011) and low body weight (HR 1.04 per 1-kg decrease, 95% CI 1.003-1.08, p=0.032) were significantly associated with re-fracture.

CONCLUSIONS

Amongst patients managed within a dedicated SFP programme, poor compliance, multiple co-morbidities, corticosteroid therapy, low hip BMD or low body weight are all associated with increased risk of re-fracture. This subgroup of patients therefore require intensive management including strategies to improve compliance.

Biochemical markers for assessment of calcium economy and bone metabolism: application in clinical trials from pharmaceutical agents to nutritional products

Nutrition plays an important role in osteoporosis prevention and treatment. Substantial progress in both laboratory analyses and clinical use of biochemical markers has modified the strategy of anti-osteoporotic drug development. The present review examines the use of biochemical markers in clinical research aimed at characterising the influence of foods or nutrients on bone metabolism. The two types of markers are: (i) specific hormonal factors related to bone; and (ii) bone turnover markers (BTM) that reflect bone cell metabolism. Of the former, vitamin D metabolites, parathyroid hormone, and insulin-like growth factor-I indicate responses to variations in the supply of bone-related nutrients, such as vitamin D, Ca, inorganic phosphate and protein. Thus modification in bone remodelling, the key process upon which both pharmaceutical agents and nutrients exert their anti-catabolic or anabolic actions, is revealed. Circulating BTM reflect either osteoclastic resorption or osteoblastic formation. Intervention with pharmacological agents showed that early changes in BTM predicted bone loss and subsequent osteoporotic fracture risk. New trials have documented the influence of nutrition on bone-tropic hormonal factors and BTM in adults, including situations of body-weight change, such as anorexia nervosa, and weight loss by obese subjects. In osteoporosis-prevention studies involving dietary manipulation, randomised cross-over trials are best suited to evaluate influences on bone metabolism, and insight into effects on bone metabolism may be gained within a relatively short time when biochemical markers are monitored.

Goal-directed treatment of osteoporosis in Europe

Despite the proven predictive ability of bone mineral density, Fracture Risk Assessment Tool (FRAX®), bone turnover markers, and fracture for osteoporotic fracture, their use as targets for treatment of osteoporosis is limited.

INTRODUCTION

Treat-to-target is a strategy applied in several fields of medicine and has recently become an area of interest in the management of osteoporosis. Its role in this setting remains controversial. This article was prepared following a European Society for Clinical and Economic Aspects of Osteoporosis and Osteoarthritis (ESCEO) working group meeting convened under the auspices of the International Osteoporosis Foundation (IOF) to discuss the feasibility of applying such a strategy in osteoporosis in Europe.

METHODS

Potential targets range from the absence of an incident fracture to fixed levels of bone mineral density (BMD), a desired FRAX® score, a specified level of bone turnover markers or indeed changes in any one or a combination of these parameters.

RESULTS

Despite the proven predictive ability of all of these variables for fracture (particularly BMD and FRAX), their use as targets remains limited due to low sensitivity, the influence of confounders and current lack of evidence that targets can be consistently reached.

CONCLUSION

ESCEO considers that it is not currently feasible to apply a treat-to-target strategy in osteoporosis, though it did identify a need to continue to improve the targeting of treatment to those at higher risk (target-to-treat strategy) and a number of issues for the research agenda. These include international consensus on intervention thresholds and definition of treatment failure, further exploration of the relationship between fracture and BMD, and FRAX and treatment efficacy and investigation of the potential of short-term targets to improve adherence.

From histology to micro-CT: Measuring and modeling resorption cavities and their relation to bone competence

The process of bone remodelling plays an essential role in the emergence and maintenance of bone geometry and its internal structure. Osteoclasts are one of the three main bone cell types that play a crucial role in the bone remodelling cycle. At the microstructural level, osteoclasts create bone deficits by eroding resorption cavities. Understanding how these cavities impair the mechanical quality of the bone is not only relevant in quantifying the impact of resorption cavities in healthy bone and normal aging, but maybe even more so in quantifying their role in metabolic bone diseases. Metabolic bone diseases and their treatment are both known to affect the bone remodelling cycle; hence, the bone mechanical competence can and will be affected. However, the current knowledge of the precise dimensions of these cavities and their effect on bone competence is rather limited. This is not surprising considering the difficulties in deriving three-dimensional (3D) properties from two-dimensional (2D) histological sections. The measurement difficulties are reflected in the evaluation of how resorption cavities affect bone competence. Although detailed 3D models are generally being used to quantify the mechanical impact of the cavities, the representation of the cavities themselves has basically been limited to simplified shapes and averaged cavity properties. Qualitatively, these models indicate that cavity size and location are important, and that the effect of cavities is larger than can be expected from simple bone loss. In summary, the dimensions of osteoclast resorption cavities were until recently estimated from 2D measures; hence, a careful interpretation of resorption cavity dimensions is necessary. More effort needs to go into correctly quantifying resorption cavities using modern 3D imaging techniques like micro-computed tomography (micro-CT) and synchrotron radiation CT. Osteoclast resorption cavities affect bone competence. The structure-function relationships have been analysed using computational models that, on one hand, provide rather detailed information on trabecular bone structure, but on the other incorporate rather crude assumptions on cavity dimensions. The use of high-resolution representations and parametric descriptions could be potential routes to improve the quantitative fidelity of these models.

Establishing reference intervals for bone turnover markers in healthy postmenopausal women in a nonfasting state

In order to interpret bone turnover markers (BTMs), we need to establish healthy reference intervals. It is difficult to establish reference intervals for older women because they commonly suffer from diseases or take medications that affect bone turnover. The aims of this study were: (1) to identify diseases and drugs that have a substantial effect on BTMs; (2) to establish reference intervals for premenopausal and postmenopausal women; and (3) to examine the effects of other factors on BTMs in healthy postmenopausal women. We studied women aged 30-39 years (n=258) and women aged 55-79 years (n=2419) from a five-European centre population-based study. We obtained a nonfasting serum and second morning void urine samples at a single baseline visit. BTMs were measured using automated immunoassay analysers. BTMs were higher in patients with vitamin D deficiency and chronic kidney disease. Three or more BTMs were higher in women who were osteoporotic and at least two BTMs were lower in women who were oestrogen replete, taking osteoporosis treatments or having diseases known to affect bone turnover. These were used as exclusion criteria for selecting the populations for the reference intervals. The reference intervals for BTMs were higher in postmenopausal than premenopausal women. Levels of BTMs were not dependent on geographical location and increased with age.

Reduced tissue-level stiffness and mineralization in osteoporotic cancellous bone

Osteoporosis alters bone mass and composition ultimately increasing the fragility of primarily cancellous skeletal sites; however, effects of osteoporosis on tissue-level mechanical properties of cancellous bone are unknown. Dual-energy X-ray absorptiometry (DXA) scans are the clinical standard for diagnosing osteoporosis though changes in cancellous bone mass and mineralization are difficult to separate using this method. The goal of this study was to investigate possible difference in tissue-level properties with osteoporosis as defined by donor T scores. Spine segments from Caucasian female cadavers (58-92 years) were used. A T score for each donor was calculated from DXA scans to determine osteoporotic status. Tissue-level composition and mechanical properties of vertebrae adjacent to the scan region were measured using nanoindentation and Raman spectroscopy. Based on T scores, six samples were in the Osteoporotic group (58-74 years) and four samples were in the Not Osteoporotic group (65-92 years). The indentation modulus and mineral to matrix ratio (mineral:matrix) were lower in the Osteoporotic group than the Not Osteoporotic group. Mineral:matrix ratio decreased with age (r (2) = 0.35, p = 0.05), and the indentation modulus increased with areal bone mineral density (r (2) = 0.41, p = 0.04). This study is the first to examine cancellous bone composition and mechanical properties from a fracture prone location with osteoporosis. We found differences in tissue composition and mechanical properties with osteoporosis that could contribute to increased fragility in addition to changes in trabecular architecture and bone volume.

Analysis of stress distribution around total hip stems custom-designed for the standardized Asian femur configuration

In total hip replacement (THR), bone resorption related to the foreign body reaction around the implant causes bonding failure at the bone–prosthesis interface and adversely affects the function and longevity of femoral implants. Stress shielding is thought to be one of the possible biomechanical factors that causes bone resorption, and is related to prosthesis design. We therefore investigated stress distribution at the bone–implant interface of implant models custom-fitted to Asian individuals, using a finite-element method. Based on the standard geometry of Asian femurs, we designed four different custom-fitted implant stems and applied boundary conditions, including a stationary loading of 1750 N. Even though stress shielding was observed for all four different prostheses, the custom-designed implant with a stepped groove in the proximal–medial region had the largest maximum principal stress distribution along paths on the bone–implant interface. This implant type also showed the highest maximum principal stress distribution at the proximal (0.308 MPa), mid (0.872 MPa) and distal (12.981 MPa) regions of the cortical surface of the femur. In conclusion, the implant design with a stepped groove in the proximal–medial region showed an overall increase in stress distribution due to minimization of stress shielding afforded by the reduced effective area in the bone–implant interface. Therefore, this hip implant type could be a possible geometry to remain functional over the long term in THR patients.

The inhibition of RANK-ligand in the management of postmenopausal osteoporosis and related fractures: the role of denosumab

There is great interest in new treatments of osteoporosis owing to general ageing of population and increased risk for fragility fractures in the elderly. Current therapies show a good efficacy in improving bone quality and bone density, but, in spite of a certain reduction in fracture rate, according to each treatment, the problem of osteoporotic fractures is yet far from to be solved. Moreover, some treatments may produce different side effects. Denosumab (Dmab), a receptor activator of nuclear factor kappa-B ligand (RANKL)-inhibitor, is an agent recently introduced in clinical practice for treatment of osteoporosis of postmenopausal women. Dmab has improved bone mineral density and prevented new vertebral and non-vertebral fractures with a similar efficacy in comparison with alendronate. Many clinical studies showed Dmab produces also significant improvement versus placebo in bone quality as indicated by decreasing markers of bone turnover. Patients using Dmab reported less risk of AFF (Atypical Femoral Fractures) and ONJ (Osteonecrosis of the Jaw) with an increased number of cellulitis. Here, we review articles using Dmab for female post-menopausal osteoporosis.

Multidetector-row computed tomography is useful to evaluate the therapeutic effects of bisphosphonates in glucocorticoid-induced osteoporosis

Osteoporosis is one of the major complications of glucocorticoid therapy. Osteoporosis is usually defined by the levels of bone mineral density (BMD) assessed by dual energy X-ray absorptiometry (DEXA); however, glucocorticoids often induce fractures in patients with normal BMD. Thus, novel diagnostic approaches are required. In this study, we examined whether multidetector-row computed tomography (MDCT) is useful to assess the bone status in glucocorticoid-induced osteoporosis (GIO). Because bisphosphonates have been proven to prevent bone fracture in GIO, we tried to detect the therapeutic effects of bisphosphonates in GIO by MDCT. Fifteen Japanese patients with immunoglobulin A nephropathy who had normal renal function were enrolled in this open-label randomized trial. Patients were randomly divided into three groups-calcitriol (VD), menatetrenone (VK), or bisphosphonate (Bis). Bone conditions were analyzed twice by three different methods-bone turnover markers, DEXA, and MDCT-at the start and 6 months after the start of therapy. Both bone markers and DEXA could not detect significant differences among the therapeutic groups; however, MDCT-based analyses detected the preventive effects of bisphosphonates in GIO. Compared to VD, Bis improved structural indices, such as bone volume fraction, trabecular separation, marrow star volume, and structure model index whereas the difference between VD and VK was not significant. Finite element analysis revealed that simulated fracture load in the Bis group was significantly improved. These findings suggested that MDCT-based assessment is superior to bone markers and/or DEXA in assessing the therapeutic effect of bisphosphonates on GIO.

Focal therapeutic irradiation induces an early transient increase in bone glycation

Advanced glycation end products (AGEs) are an abnormal modification of the collagenous matrix in bone, and their accumulation contributes to alteration of mechanical properties. Using a mouse model of focal external radiotherapy, we quantified the time-dependent changes in the glycation of bone collagen after 4 daily fractions of 5 Gy exposure to unilateral hindlimb. Fluorometric analysis of decalcified femurs demonstrated a significant and transient increase in the quantity of pentosidine, pyridinolines and nonspecific AGEs per unit of collagen at one week postirradiation. These differences did not persist at 4, 8, 12 or 26 weeks postirradiation. Radiation had no effect on bone collagen content. We hypothesize that following the transient increase in glycation products, these crosslinks are then removed as a result of increased postirradiation osteoclast activity and continued mineralization of the bone.

Chemical structure, biosynthesis and synthesis of free and glycosylated pyridinolines formed by cross-link of bone and synovium collagen

This review focuses on the chemical structure, biosynthesis and synthesis of free and glycosylated pyridinolines (Pyds), fluorescent collagen cross-links, with a pyridinium salt structure. Pyds derive from the degradation of bone collagen and have attracted attention for their use as biochemical markers of bone resorption and to assess fracture risk prediction in persons suffering from osteoporosis, bone cancer and other bone or collagen diseases. We consider and critically discuss all reported syntheses of free and glycosylated Pyds evidencing an unrevised chemistry, original and of general utility, analysis of which allows us to also support a previously suggested non-enzymatic formation of Pyds in collagen better rationalizing and justifying the chemical events.

Multifactorial risk profile for bone fractures in primary hyperparathyroidism

Primary hyperparathyroidism (pHPT) is associated with an increased fracture risk, and decreased bone density thus has been considered an indication for surgery. However, many pHPT patients have a multifactorial risk profile for osteoporosis and bone fractures. The aim of the present study was to evaluate variables associated with fracture risk within the group of pHPT patients. A series of 203 consecutive patients operated for pHPT were investigated with bone mineral content and biochemical and clinical risk factors for bone fracture. Seventeen patients (8%) had a history of at least one bone fracture up to 5 years before pHPT surgery. Twenty-six patients (13%) had a history of at least one fracture during the 10-year period prior to surgery. In the univariate analyses corticosteroid treatment, serum levels of alkaline phosphatase, 25-hydroxyvitamin D3, type I collagen telopeptide, and bone mineral content were found to be associated with a history of bone fractures up to 10 years before surgery. Additionally, age and menopausal status were of importance for fractures during the 10-year-period, whereas a history of cardiovascular disease was important for fractures during the 5-year-period prior to surgery. Multivariate analyses showed that serum level of PTH was independently associated with bone fractures during the 5-year period prior to pHPT surgery and further that serum level of 25-hydroxyvitamin D3 was associated with fractures up to 10 years before surgery. In conclusion, serum levels of 25-hydroxyvitamin D3 and PTH were independently associated with a history of bone fractures in pHPT. These variables should be considered when evaluating patients for parathyroid surgery.

Biochemical markers of bone turnover - uses and limitations

Bone turnover markers of resorption and formation are released during the process of bone remodelling. These markers have been extensively studied in a number of therapeutic trials of osteoporosis during the past decade. This has led to better understanding of their physiology, clinical applications and possible ways to optimize analytical techniques. Bone markers can complement the results of bone mineral density in the management of osteoporosis, but their use in clinical practice is challenged by pre-analytical and analytical variability. This review will discuss different types of bone markers, their limitations, use in different metabolic bone diseases and current recommendations from the International Osteoporosis Foundation and the International Federation of Clinical Chemistry and Laboratory Medicine bone marker standards working group.

Update on long-term treatment with bisphosphonates for postmenopausal osteoporosis: a systematic review

INTRODUCTION

Osteoporosis is a progressive skeletal disorder that requires long-term treatment. However, there is little guidance regarding optimal treatment duration and what the treatment discontinuation and retreatment criteria should be. Given that bisphosphonates are the most commonly prescribed class of agent for the treatment of osteoporosis, we reviewed the long-term data relating to these therapies and discussed the considerations for using bisphosphonates in postmenopausal women with osteoporosis.

METHODS

A PubMed search, using the search terms 'bisphosphonate', 'postmenopausal osteoporosis' and 'long term' and/or 'extension' was conducted in January 2013. Results from nine controlled studies that prospectively assessed alendronate, risedronate, ibandronate or zoledronic acid in women with postmenopausal osteoporosis were reviewed.

FINDINGS

Clinical studies in postmenopausal women with osteoporosis showed that long-term use of bisphosphonates resulted in persistent antifracture and bone mineral density (BMD) increasing effects beyond 3 years of treatment. No unexpected adverse events were identified in these studies and the long-term tolerability profiles of bisphosphonates remain favorable. Data from the withdrawal extension studies of alendronate and zoledronic acid also showed that residual fracture benefits were seen in patients who discontinued treatment for 3 to 5 years after an initial 3- to 5-year treatment period. BMD monitoring and fracture risk assessments should be conducted regularly to determine whether treatment could be stopped or should be reinitiated. Patients exhibiting T-scores<-2.5 or who have suffered a new fracture while on treatment should continue treatment, while patients with T-scores>-2.5 could be considered for discontinuation of active treatment while undergoing continued monitoring of their bone health. The duration and potential discontinuation of treatment should be personalized for individual patients based on their response to treatment, fracture risk and comorbidities.

Association between the metabolome and low bone mineral density in Taiwanese women determined by (1)H NMR spectroscopy

Osteoporosis is related to the alteration of specific circulating metabolites. However, previous studies on only a few metabolites inadequately explain the pathogenesis of this complex syndrome. To date, no study has related the metabolome to bone mineral density (BMD), which would provide an overview of metabolism status and may be useful in clinical practice. This cross-sectional study involved 601 healthy Taiwanese women aged 40 to 55 years recruited from MJ Health Management Institution between 2009 and 2010. Participants were classified according to high (2nd tertile plus 3rd tertile) and low (1st tertile) BMD groups. The plasma metabolome was evaluated by proton nuclear magnetic resonance spectroscopy ((1) H NMR). Principal components analysis (PCA), partial least-squares discriminant analysis (PLS-DA), and logistic regression analysis were used to assess the association between the metabolome and BMD. The high and low BMD groups could be differentiated by PLS-DA but not PCA in postmenopausal women (Q(2)  = 0.05, ppermutation  = 0.04). Among postmenopausal women, elevated glutamine was significantly associated with low BMD (adjusted odds ratio [AOR] = 5.10); meanwhile, elevated lactate (AOR = 0.55), acetone (AOR = 0.51), lipids (AOR = 0.04), and very low-density lipoprotein (AOR = 0.49) protected against low BMD. To the best of our knowledge, this study is the first to identify a group of metabolites for characterizing low BMD in postmenopausal women using a (1) H NMR-based metabolomic approach. The metabolic profile may be useful for predicting the risk of osteoporosis in postmenopausal women at an early age.

Circulating sclerostin levels and markers of bone turnover in Chinese-American and white women

CONTEXT

Chinese-American women have bone microarchitectural features that confer greater bone stiffness compared to white women, but the physiology underlying these findings has not been investigated.

OBJECTIVE

The purpose of the study was to assess racial differences in serum sclerostin and bone turnover markers (BTMs), and to explore their associations with each other, volumetric bone mineral density (BMD), and bone microarchitecture in Chinese-American and white women.

DESIGN AND SETTING

We conducted a cross-sectional study at a university hospital.

PARTICIPANTS

We studied 138 women.

RESULTS

Serum osteocalcin was 19-28% lower in pre- and postmenopausal Chinese-American vs white women, respectively (both P < .01). C-Terminal telopeptide of type I collagen (CTX) level was 18-22% lower in pre- and postmenopausal Chinese-American vs white women (both P < .05). Pre- vs postmenopausal differences in osteocalcin and CTX were greater in white vs Chinese-American women. Sclerostin levels were similar in both races, but BTMs were differentially associated with sclerostin by race and menopausal status. BTMs were not correlated with sclerostin in Chinese-Americans. CTX and bone-specific alkaline phosphatase were positively associated with sclerostin (r = 0.353, r = 0.458; both P < .05) in white premenopausal women. In contrast, in postmenopausal white women, the associations of sclerostin with amino-terminal propeptide of type I procollagen, isoform 5b of tartrate-resistant acid phosphatase, and CTX were negative (all P < .05). Adjusting for covariates, sclerostin was positively associated with areal BMD in both races.

CONCLUSIONS

Lower BTMs in Chinese-American women and greater age-related differences in BTMs among white women provide a physiological framework to account for racial differences in BMD, microarchitecture, and fracture.

Effect of Korean Red Ginseng on radiation-induced bone loss in C3H/HeN mice

This study investigated the effects of Korean Red Ginseng (KRG) on radiation-induced bone loss in C3H/HeN mice. C3H/HeN mice were divided into sham and irradiation (3 Gy, gamma-ray) groups. The irradiated mice were treated for 12 wk with vehicle, KRG (per os, p.o.) or KRG (intraperitoneal). Serum alkaline phosphatase (ALP), tartrate-resistant acid phosphatase, estradiol level, and biomechanical properties were measured. Tibiae were analyzed using micro-computed tomography. Treatment of KRG (p.o., 250 mg/kg of body weight/d) significantly preserved trabecular bone volume, trabecular number, structure model index, and bone mineral density of proximal tibia metaphysic, but did not alter the uterus weight of the mice. Serum ALP level was slightly reduced by KRG treatment. However, grip strength, mechanical property, and cortical bone architecture did not differ among the experimental groups. The results indicate that KRG can prevent radiation-induced bone loss in mice.

Genetic influence on bone phenotypes and body composition: a Swedish twin study

Bone mineral density (BMD), bone size and bone turnover are independent determinants of fractures in elderly. Earlier twin studies of these phenotypes have revealed high heritability for BMD and bone area, and more moderate heritability for bone turnover markers. No previous Scandinavian study has evaluated the genetic and environmental contribution to the variance of these phenotypes, despite the fact that Scandinavian countries have the highest incidence of osteoporotic fractures worldwide. Participants were selected from the Swedish Twin Registry. All intact like-sexed twin pairs born in 1965 or earlier and living in the county of Uppsala were invited to participate. A total of 102 twin pairs (45 monozygotic and 57 dizygotic) accepted the invitation to participate. All twins underwent measurement of BMD and bone area using dual-energy X-ray absorptiometry. Hip geometry was also calculated. Markers for bone formation (osteocalcin) and bone resorption (CrossLaps) were measured in serum. We observed a substantial heritability for BMD at the lumbar spine (0.85; 95 % CI 0.54-0.90), the femoral neck (0.75; 95 % CI 0.62-0.83), and the proximal femur (0.84; 95 % CI 0.74-0.90). The values for bone area were approximately similar to those for BMD. Bone turnover markers had a slightly lower genetic influence with a value of 0.69 (0.53-0.80) for osteocalcin and 0.58 (95 % CI 0.33-0.75) for CrossLaps. As a comparison, the heritabilities of body height and weight were 0.95 and 0.82, respectively. The high heritability on bone phenotypes among Swedish middle-aged and older men and women should encourage further work on the identification of specific genetic pathways. Continuing research in this area could reveal the mechanisms behind the strong genetic susceptibility of bone-related phenotypes.

A cross-sectional association between bone mineral density and parathyroid hormone and other biomarkers in community-dwelling young adults: the CARDIA study

CONTEXT

Most association studies of bone-related biomarkers (BBMs) with bone mineral density (BMD) have been conducted in postmenopausal women.

OBJECTIVE

We tested whether the following BBMs were cross-sectionally associated with BMD among young adults: serum 1,25-dihydroxyvitamin D (1,25(OH)2D), 25-hydroxyvitamin D (25OHD), PTH, osteocalcin, bone-specific alkaline phosphatase (BAP), and urinary pyridinoline/urinary creatinine.

SETTING AND PARTICIPANTS

We studied 319 individuals (134 women, 149 black, 24-36 years) recruited during 1992 through 1993 in Oakland, California. BMD was assessed with dual-energy x-ray absorptiometry. Linear regression models estimated the association between BMD and each BBM.

RESULTS

1,25(OH)2D was inversely associated with all BMDs. 25OHD was positively, and PTH inversely, associated with lumbar spine, total hip, and whole-body BMD. BAP was inversely associated with left arm, right arm, and whole-body BMD but not with spine or hip BMD. Neither osteocalcin nor urinary pyridinoline/urinary creatinine was associated with BMD. When we placed all BBMs (including 1,25(OH)2D) in one model, the pattern and magnitude of association was similar except for PTH, which was attenuated. The association of BMD and BBMs did not differ significantly by race or sex.

CONCLUSIONS

In this cross-sectional study of healthy young men and women who had PTH levels considered normal in clinical practice, higher PTH was associated with lower BMD, particularly in weight-bearing sites (ie, spine and hip). The inverse association of 1,25(OH)2D, together with the attenuation of PTH, suggests that the observed association of PTH is mediated by 1,25(OH)2D. BAP was inversely associated with arm BMD. BBMs can be important markers of skeletal activity in young adults, but their clinical role on bone health among this population is yet to be fully determined.

Vitamin D and bone health outcomes in older age

The aim of this review is to summarise the evidence linking vitamin D to bone health outcomes in older adults. A plethora of scientific evidence globally suggests that large proportions of people have vitamin D deficiency and are not meeting recommended intakes. Older adults are at particular risk of the consequences of vitamin D deficiency owing to a combination of physiological and behavioural factors. Epidemiological studies show that low vitamin D status is associated with a variety of negative skeletal consequences in older adults including osteomalacia, reduced bone mineral density, impaired Ca absorption and secondary hyperparathyroidism. There seems to be inconsistent evidence for a protective role of vitamin D supplementation alone on bone mass. However, it is generally accepted that vitamin D (17·5 μg/d) in combination with Ca (1200 mg/d) reduces bone loss among older white subjects. Evidence for a benefit of vitamin D supplementation alone on reducing fracture risk is varied. According to a recent Agency for Healthcare Research and Quality review in the USA the evidence base shows mixed results for a beneficial effect of vitamin D on decreasing overall fracture risk. Limitations such as poor compliance with treatment, incomplete assessment of vitamin D status and large drop-out rates however, have been highlighted within some studies. In conclusion, it is generally accepted that vitamin D in combination with Ca reduces the risk of non-vertebral fractures particularly those in institutional care. The lack of data on vitamin D and bone health outcomes in certain population groups such as diverse racial groups warrants attention.