Prediction of bone loss using biochemical markers of bone turnover

Longitudinal Change in Bone Density, Geometry, and Estimated Bone Strength in Older Men and Women From The Gambia: Findings From the Gambian Bone and Muscle Aging Study (GamBAS)

Musculoskeletal aging in the most resource-limited countries has not been quantified, and longitudinal data are urgently needed to inform policy. The aim of this prospective study was to describe musculoskeletal aging in Gambian adults. A total of 488 participants were recruited stratified by sex and 5-year age band (aged 40 years and older); 386 attended follow-up 1.7 years later. Outcomes were dual-energy X-ray absorptiometry (DXA) (n = 383) total hip areal bone mineral density (aBMD), bone mineral content (BMC), bone area (BA); peripheral quantitative computed tomography (pQCT) diaphyseal and epiphyseal radius and tibia (n = 313) total volumetric BMD (vBMD), trabecular vBMD, estimated bone strength indices (BSIc), cross-sectional area (CSA), BMC, and cortical vBMD. Mean annualized percentage change in bone outcomes was assessed in 10-year age bands and linear trends for age assessed. Bone turnover markers, parathyroid hormone (PTH), and 25-hydroxyvitamin D (25(OH)D) were explored as predictors of change in bone. Bone loss was observed at all sites, with an annual loss of total hip aBMD of 1.2% in women after age 50 years and in men at age 70 years plus. Greater loss in vBMD and BSIc was found at the radius in both men and women; strength was reduced by 4% per year in women and 3% per year in men (p trend 0.02, 0.03, respectively). At cortical sites, reductions in BMC, CSA, and vBMD were observed, being greatest in BMC in women, between 1.4% and 2.0% per annum. Higher CTX and PINP predicted greater loss of trabecular vBMD in women and BMC in men at the radius, and higher 25(OH)D with less loss of tibial trabecular vBMD and CSA in women. The magnitude of bone loss was like those reported in countries where fragility fracture rates are much higher. Given the predicted rise in fracture rates in resource-poor countries such as The Gambia, these data provide important insights into musculoskeletal health in this population. © 2022 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).

Exploring the Relationship of Bone Turnover Markers and Bone Mineral Density in Community-Dwelling Postmenopausal Women

Aims

To explore the relationships of procollagen type 1 N-terminal propeptide (P1NP) and β cross-linked C-telopeptide of type 1 collagen (β-CTX) with bone mineral density (BMD) in postmenopausal women.

Methods

All postmenopausal women were selected from a community-based case-control study. The anteroposterior L1-L4 and left proximal femur BMD were measured. P1NP and β-CTX were also collected and tested. The main correlation analysis was applied to explore the relationships of BMD, P1NP, and β-CTX.

Results

The total 1055 postmenopausal women were enrolled. The BMD at all sites kept a decrease continually with age (P < 0.01). In addition, the level of β-CTX increased significantly from 45 to 50 years old and remained at a high level in the later stage, while the level of P1NP changed little or even decreased with age. Logistic regression model showed that β-CTX has better ability to predict BMD than P1NP, as demonstrated by an area under the curve (AUC) of 0.63.

Conclusion

P1NP and β-CTX are important markers to monitor bone metabolism. This trial is registered with ChiCTR-SOC-17013090. The date of registration is Oct. 23, 2017.

Changes in bone mineral density over 10 years in patients with early rheumatoid arthritis

Objectives

To investigate changes in bone mineral density (BMD) in patients with early rheumatoid arthritis (RA) over a 10-year period.

Methods

Consecutive patients with early RA (symptom duration <12 months) were followed according to a structured programme and examined with dual-energy X-ray absorptiometry (DXA) at inclusion and after 2, 5 and 10 years. Mean Z-scores over the study period were estimated using mixed linear effect models. Changes in Z-scores between follow-up visits were analysed using paired T-tests.

Results

At inclusion, 220 patients were examined with DXA. At the femoral neck, the mean Z-score over 10 years was −0.33 (95 % CI −0.57 to −0.08) in men and −0.07 (−0.22 to 0.08) in women. Men had significantly lower BMD at the femoral neck than expected by age at inclusion (intercept Z-score value −0.35; 95 % CI −0.61 to −0.09), whereas there was no such difference in women. At the lumbar spine, the mean Z-score over the study period for men was −0.05 (−0.29 to 0.19) and for women 0.06 (−0.10 to 0.21). In paired comparisons of BMD at different follow-up visits, femoral neck Z-scores for men decreased significantly from inclusion to the 5-year follow-up. After 5 years, no further reduction was seen.

Conclusions

In this observational study of a limited sample, men with early RA had reduced femoral neck BMD at diagnosis, with a further significant but marginal decline during the first 5 years. Lumbar spine BMD Z-scores were not reduced in men or women with early RA. Data on 10-year follow-up were limited.

Osteocalcin and Abdominal Aortic Calcification in Hemodialysis Patients: An Observational Cross-Sectional Study

OBJECTIVES

To investigate the serum level of osteocalcin (OC), also known as bone Gla protein, in maintenance hemodialysis (MHD) patients and its correlation with abdominal aortic calcification (AAC).

METHODS

From July 2017 to February 2020, we enrolled 108 adult MHD patients. Routine fasting blood laboratory tests were performed before the start of the second hemodialysis in a week. Abdominal aortic calcification score (AACs) was assessed within 1 month. Pearson correlation and Logistic regression were used to analyze the data.

RESULTS

The OC level was 231.56 (25.92,361.33) ng/ml, elevating significantly in this group of MHD patients. It had a positive correlation with serum phosphorus (r = 0.511, P = 0.001), intact parathyroid hormone(iPTH) (r = 0.594, P = 0.0001), fibroblast growth factor 23(FGF23) (r = 0.485, P = 0.003) and a negative correlation with age(r = -0.356, P = 0.039). Based on the AACs, patients were divided into two groups. Serum OC level were higher in patients with AACs≥5 (p=0.032). A multiple logistics regression analysis revealed that age (odds ratio [OR]1.14, P=0.005) and OC(OR=1.10, P=0.008)were risk factors for high AACs(≥5).

CONCLUSION

The study implicated that OC elevated significantly in this group of MHD patients.OC is positively correlated with phosphorus, iPTH, FGF23, and a negative correlation with age. OC was a risk factor for vascular calcification in this study, but this study did not classify osteocalcin as c-OC and unOC. Whether unOC is associated more directly with vascular calcification requires further study.

Intradialytic Calcium Kinetics and Cardiovascular Disease in Chronic Hemodialysis Patients

BACKGROUND/OBJECTIVE

Calcium loading has been associated with cardiovascular risk in hemodialysis (HD) patients. However, it remains to be elucidated whether alterations of intradialytic calcium buffering add to the increased cardiovascular disease burden in this high-risk population.

METHODS

Intradialytic calcium kinetics was evaluated in a cross-sectional observational study by measuring dialysate-sided ionized calcium mass balance (iCaMB), calcium buffer capacity, and change in serum calcium levels in 40 chronic HD patients during a routine HD session. A dialysate calcium of 3.5 mEq/L was used to adequately challenge calcium buffer mechanisms. Aortic pulse wave velocity and serum osteocalcin levels were measured prior to the HD session. Presence of cardiovascular disease and diabetes was assessed.

RESULTS

The mean dialysate-sided iCaMB, extracellular fluid ionized calcium mass gain, and buffered ionized calcium mass were 469 (±154), 111 (±49), and 358 (±145) mg/HD, respectively. The mean ionized serum calcium increase (∆iCa) was 0.42 (±0.14) mEq/L per HD. The mean intradialytic calcium buffer capacity was 73 (±18)%. Multivariate regression analysis revealed significant independent association of (1) iCaMB with the dialysate-to-blood calcium gradient at HD start and (2) intradialytic calcium buffer capacity with undercarboxylated osteocalcin. The presence of coronary heart disease was associated with higher ∆iCa but not iCaMB in the multivariate model.

CONCLUSIONS

In line with our proof-of-concept study, we provide clinical evidence for a rapidly accessible and exchangeable calcium pool involved in intradialytic calcium regulation and for the role of osteocalcin as a potential biomarker. Our findings argue for evaluating the prognostic potential of intradialytic calcium kinetics in prospective clinical trials.

Magnesium Intake Predicts Bone Turnover in Postmenopausal Black South African Women

This prospective study investigated the association between nutrient intake, dietary patterns, and changes in bone turnover and bone mineral density (BMD) in postmenopausal urban black South African women over two years. These women (n = 144) underwent BMD measurements at the distal radius, lumbar spine, femoral neck (FN), as well as a biochemical analysis which included the parathyroid hormone (PTH), 25-hydroxyvitamin D, C-Telopeptide of type I collagen (CTX-1) in 2010 and 2012. Their dietary intake was assessed in 2010 using a food frequency questionnaire, and sociodemographic and health information was collected. Four dietary patterns explained 54.4% of the variance of dietary intake, namely staple foods and processed meats, home cooking, snacking, and high sugar. Dietary magnesium negatively correlated with CTx-1 in 2012 (r = −0.21, p = 0.02), calcium correlated with distal radius BMD in 2010 (r = 0.22, p = 0.01) and 2012 (r = 0.24, p = 0.005), and the snacking dietary pattern score correlated with FN BMD in 2010 (r = 0.18, p = 0.03) and 2012 (r = 0.21, p = 0.02). The baseline CTx-1 and dietary magnesium intake predicted 22% of the variance in percentage change of CTx-1 over two years (p < 0.001).The magnesium intake predicted short-term bone resorption over two years.

Relationship between bone turnover markers and the heel stiffness index measured by quantitative ultrasound in post-menopausal Japanese women

Background: Osteoporosis in women is a serious health problem. The relationships between biochemical markers of bone turnover and bone mineral density (BMD) in women have been reported, but no study has examined relationships between tartrate-resistant acid phosphatase-5b (TRACP-5b) or bone-specific alkaline phosphatase (BAP) and bone mass measured by quantitative ultrasound (QUS) in Japanese post-menopausal women. Aim: To investigate the serum TRACP-5b and BAP levels and to determine their associations with the heel stiffness index measured by QUS in post-menopausal women. Subjects and methods: The subjects were 510 post-menopausal women who were invited to participate in periodic health examinations in 2011-2013 (the Unzen Study). The heel stiffness index (bone mass) was measured by QUS. Serum samples were collected and TRACP-5b and BAP levels were measured. Results: Multiple regression analysis showed that a higher log (TRACP-5b) was correlated with a lower stiffness index (p = 0.014) and log (BAP) was not correlated with stiffness index after adjusting for covariates (p = 0.136). Conclusion: Higher rates of bone resorption are associated with a lower stiffness index in Japanese post-menopausal women. These results may indicate that high bone resorption affects bone mass more than bone formation, resulting in a low bone mass.

Vitamin D supplementation and bone turnover in advanced heart failure: the EVITA trial

Low vitamin D status is common in patients with heart failure and may influence bone health. A daily vitamin D dose of 4000 IU (moderately high dose) for 3 years had however no effect on parameters of bone metabolism, even in patients with very low vitamin D status.

INTRODUCTION

Low vitamin D status is common in patients with heart failure (HF) and has been related to disturbed bone turnover. The present study investigated the effect of a daily vitamin D₃ dose of 4000 IU on bone turnover markers (BTMs) in patients with advanced HF and 25-hydroxyvitamin D (25OHD) concentrations < 75 nmol/L.

METHODS

In this pre-specified secondary analysis of a randomized controlled trial, we assessed in 158 male HF patients (vitamin D group: n = 80; placebo group: n = 78) between-group differences in calciotropic hormones (25OHD, 1,25-dihydroxyvitamin D [1,25(OH)₂D], intact parathyroid hormone [iPTH]), and BTMs (cross-linked C-telopeptide of type I collagen, bone-specific alkaline phosphatase, undercarboxylated osteocalcin). Comparisons were performed at the end of a 3-year vitamin D supplementation period with adjustments for baseline values.

RESULTS

Compared with placebo, vitamin D increased 25OHD on average by 54.3 nmol/L. At study termination, 25OHD and 1,25(OH)₂D were significantly higher (P < 0.001 and P = 0.007, respectively), whereas iPTH tended to be lower in the vitamin D group than in the placebo group (P = 0.083). BTMs were initially within their reference ranges and did not differ significantly between groups at study termination, neither in the entire study cohort nor when data analysis was restricted to the subgroup of patients with initial 25OHD concentrations < 30 nmol/L (n = 54) or to patients with initial hyperparathyroidism (n = 65) (all P values > 0.05).

CONCLUSIONS

A daily vitamin D₃ dose of 4000 IU did not influence BTMs. Data indicate that vitamin D supplementation will not lower bone turnover in male patients with heart failure.

Relationship between bone turnover markers and the heel stiffness index measured by quantitative ultrasound in middle-aged and elderly Japanese men

The aim of the present study was to investigate the age-related patterns and the relationships between serum levels of tartrate-resistant acid phosphatase-5b (TRACP-5b) or bone-specific alkaline phosphatase (BAP), and the heel stiffness index measured by quantitative ultrasound (QUS) in 429 Japanese men, with special emphasis on 2 age groups (40-59 years and 60 years or over). The heel stiffness index (bone mass) was measured by QUS. Serum samples were collected, and TRACP-5b and BAP levels were measured. The stiffness index was significantly decreased with age. Log (TRACP-5b) was significantly increased with age, but Log (BAP) was stable. Generalized linear models showed that higher levels of Log (TRACP-5b) and Log (BAP) were correlated with a lower stiffness index after adjusting for covariates in men aged 60 years or over, but not in men aged 40 to 59 years. In conclusion, higher rates of bone turnover markers were associated with a lower stiffness index only in elderly men. These results may indicate a different mechanism of low bone mass among different age groups of men.

Muscle strength and regional lean body mass influence on mineral bone health in young male adults

The relationship between muscle strength and bone mineral content (BMC) and bone mineral density (BMD) is supposed from the assumption of the mechanical stress influence on bone tissue metabolism. However, the direct relationship is not well established in younger men, since the enhancement of force able to produce effective changes in bone health, still needs to be further studied. This study aimed to analyze the influence of muscle strength on BMC and BMD in undergraduate students. Thirty six men (24.9 ± 8.6 y/o) were evaluated for regional and whole-body composition by dual energy X-ray absorptiometry (DXA). One repetition maximum tests (1RM) were assessed on flat bench-press (BP), lat-pull down (LPD), leg-curl (LC), knee extension (KE), and leg-press 45° (LP45) exercises. Linear regression modelled the relationships of BMD and BMC to the regional body composition and 1RM values. Measurements of dispersion and error (R²_adj and standard error of estimate (SEE)) were tested, setting ρ at ≤0.05. The BMD mean value for whole-body was 1.12±0.09 g/cm² and BMC attained 2477.9 ± 379.2 g. The regional lean mass (LM) in upper-limbs (UL) (= 6.80±1.21 kg) was related to BMC and BMD for UL (R²_adj = 0.74, p<0.01, SEE = 31.0 g and R²_adj = 0.63, SEE = 0.08 g/cm²), and LM in lower-limbs (LL) (= 19.13±2.50 kg) related to BMC and BMD for LL (R²_adj = 0.68, p<0,01, SEE = 99.3 g and R²_adj = 0.50, SEE = 0.20 g/cm²). The 1RM in BP was related to BMD (R²_adj = 0.51, SEE = 0.09 g/cm²), which was the strongest relationship among values of 1RM for men; but, 1RM on LPD was related to BMC (R²_adj = 0.47, p<0.01, SEE = 44.6 g), and LC was related to both BMC (R²_adj = 0.36, p<0.01, SEE = 142.0 g) and BMD (R²_adj = 0.29, p<0.01, SEE = 0.23 g/cm²). Hence, 1RM for multi-joint exercises is relevant to BMC and BMD in young men, strengthening the relationship between force and LM, and suggesting both to parametrizes bone mineral health.

The Impact of Osteocalcin, Osteoprotegerin and Osteopontin on Arterial Stiffness in Chronic Renal Failure Patients on Hemodialysis

BACKGROUND/AIMS

This cross-sectional study was designed to assess the relationship between vascular stiffness (VS) and bone-related proteins involved in the development of arteriosclerosis in patients on regular hemodialysis (HD).

METHODS

68 consecutive patients in stable clinical condition who received regular HD in the FMC Dialysis Center, Pécs were included. VS parameters (carotid-femoral pulse wave velocity - PWV, aortic augmentation index - AIx) were determined by applanation tonometry (SphygmoCor, AtCor Medical, Sidney) and the routine latoratory test were completed with measurements of osteocalcin (OC), osteopontin (OP) and osteoprotegerin (OPG) by using commercially available ELISA kits. 35 heathcare workers served as controls.

RESULTS

In patients on regular HD PWV markedly increased and there was several-fold elevation in the interrelated bone-specific proteins (OC, OP, OPG). PWV was found to be independently associated only with OC (β:-0.25, p<0.029) and age (r=0.411,p<0.000), but risk factors for arterial calcification had significant impact on OC (systolic blood pressure, hsCRP, BMI), OPG (age, BMI) and OP (LDL-cholesterol).

CONCLUSION

Except for OC, our results failed to document direct association of vascular lesion with OP and OPG, therefore their high circulating levels may be an epiphenomenon or they may have counter-regulatory role to attenuate the uremic calcification process.

Osteocalcin as a potential risk biomarker for cardiovascular and metabolic diseases

Clear evidence supports a role for circulating and locally-produced osteocalcin (OC) in the pathophysiology of cardiovascular (CV) lesions and CV risk, also in combination with metabolic changes, including type 2 diabetes mellitus (T2DM). Reduced plasma OC levels are associated with greater incidence of pathological CV changes, like arterial and valvular calcification, coronary and carotid atherosclerosis and increased carotid intima-media thickness. The actual relationship between OC levels and incidence of major CV events is, however, still unclear. Moreover, reduced circulating OC levels have been mostly associated with insulin resistance, metabolic syndrome or T2DM, indicating relevant OC actions on pancreatic β-cells and insulin secretion and activity. Based on these observations, this review article will attempt to summarize the current evidence on the potential usefulness of circulating OC as a biomarker for CV and metabolic risk, also evaluating the currently open issues in this area of research.

Changes in bone mineral density and bone turnover in patients on 'drug holiday' following bisphosphonate therapy: real-life clinic setting

OBJECTIVES

Treatment discontinuation after long-term bisphosphonate (BP), termed a 'drug holiday', has been proposed to reduce the risk of BP-associated complications. The duration of treatment cessation remains unclear. Changes in bone mineral density (BMD), bone turnover markers (BTMs) and their relationship with FRAX were assessed to help determine the optimum length of a 'drug holiday'.

METHODS

A retrospective analysis of 134 patients (13M, 121F) aged [mean (SD)] 68·4 (8·2) years who discontinued BPs after treatment for 5·9 (3·0) years for osteoporosis was undertaken. BMD at the lumbar spine (LS), total hip (TH), and femoral neck (FN) and biochemical parameters including serum 25 (OH) vitamin D, bone turnover markers (plasma CTX, P1NP) and FRAX scores were determined at discontinuation, 12-18 months and 24-30 months off treatment.

RESULTS

BMD decreased significantly at the LS [% change mean (SD): -0·94 (3·6), P = 0·008], TH [-1·4 (2·4), P < 0·001] and FN [-1·8 (4·4), P < 0·001] after treatment discontinuation for 12-18 months. In the subgroup who remained off treatment for 24-30 months, a progressive decline in BMD was seen at the TH and FN with total % decrease of -2·52 (3·5) and -2·7 (4·76), P < 0·001, respectively. CTX and P1NP increased significantly at 12-18 months after discontinuation [% change CTX: 95 (88), P < 0·001, P1NP: 88 (73), P < 0·001]. FRAX scores were significant predictors of % change in BMD at the FN (P < 0·05), independently of bone turnover and vitamin D status. In summary, our data show that following a 'drug holiday', the use of DEXA scans, BTMs and FRAX may help guide when to resume treatment.

Differential effects of calcium- and vitamin D-fortified milk with FOS-inulin compared to regular milk, on bone biomarkers in Chinese pre- and postmenopausal women

PURPOSE

To compare the effects of a high-calcium vitamin D-fortified milk with added FOS-inulin versus regular milk on serum parathyroid hormone, and bone turnover markers in premenopausal (Pre-M) and postmenopausal (PM) women over 12 weeks.

METHODS

Premenopausal women (n = 136, mean age 41 (±5) years) and postmenopausal women [n = 121, mean age 59 (±4) years] were recruited, and each age group randomised into two groups to take two glasses per day of control = regular milk (500 mg calcium per day) or intervention (Int) = fortified milk (1000 mg calcium for pre-M women and 1200 mg calcium for PM women, 96 mg magnesium, 2.4 mg zinc, 15 µg vitamin D, 4 g FOS-inulin per day). At baseline, week 4 and week 12 serum minerals and bone biochemical markers were measured and bone density was measured at baseline.

RESULTS

Mean 25-hydroxyvitamin D [25(OH) vitamin D3] levels among groups were between 49 and 65 nmol/L at baseline, and over the 12 weeks of supplementation, the fortified milk improved vitamin D status in both Int groups. CTx-1 and PINP reduced significantly in both Pre-M and PM groups over the 12 weeks, with the changes in CTx-1 being significantly different (P < 0.035) between PM control and PM Int groups at week 12. Parathyroid hormone levels were significantly reduced in all groups over time, except for control PM group where levels increased at 12 weeks.

CONCLUSION

The overall pattern of responses indicates that while both regular milk and fortified milk reduce bone resorption in young and older women, fortified milk is measurably more effective.

Bone turnover markers predict hip bone loss in elderly European men: results of the European Male Ageing Study (EMAS)

SUMMARY

The aim of this study was to determine whether bone turnover markers (BTMs) predict changes in areal bone mineral density (aBMD) in middle-aged and elderly European men. Older men with high bone turnover are at a higher risk of accelerated hip bone loss, but the clinical utility of BTMs in individuals is limited.

INTRODUCTION

Prospective studies on the value of BTMs to predict changes in aBMD in men are few and conflicting. The aim of this study was to determine whether BTMs predict changes in aBMD in middle-aged and elderly European men.

METHODS

In 487 men aged 40-79 years from the European Male Ageing Study (EMAS), BTMs were assessed at baseline and dual-energy X-ray absorptiometry (DXA) at the lumbar spine (LS), femoral neck (FN) and total hip (TH) was performed at baseline and after a mean follow-up of 4.3 years.

RESULTS

The mean aBMD decreased by 0.32%/year at FN and 0.22%/year at TH and increased by 0.32%/year at LS. Higher baseline levels of β C-terminal cross-linked telopeptide (β-CTX) and N-terminal propeptide of type I procollagen (PINP) were significantly associated with higher loss of hip aBMD in the whole cohort and men aged 60-79 years. These associations remained significant after adjustment for age, centre and body mass index (BMI). Men aged 60-79 years with β-CTX in the upper quintile were more likely of being in the upper quintile of annual percentage (%) aBMD loss at FN (OR=4.27; 95% CI=2.09-8.73) and TH (OR=3.73; 95% CI=1.84-7.57). The positive predictive value (PPV) was 46% at both hip sites.

CONCLUSION

Older men with high bone turnover have a higher risk of accelerated hip bone loss, but the PPV is low. BTMs are therefore unlikely to be of clinical utility in predicting accelerated hip bone loss in individual subjects.

Serum osteocalcin levels are inversely associated with plasma glucose and body mass index in healthy Chinese women

AIM

Osteocalcin, a biochemical marker of bone formation, has been suggested to be involved in the regulation of energy metabolism. The aim of this study was to investigate the possible association between serum osteocalcin and markers of glucose and lipid metabolism in a large sample of healthy Chinese women.

METHODS

A total of 2032 healthy Chinese women in Shanghai, aged 20-94 (including 1396 discovery-study subjects and 636 postmenopausal women for a reduplication analysis) were recruited. Their serum osteocalcin, calcium and the relevant measurements were analyzed. A Spearman correlation analysis was performed between osteocalcin and the other markers of energy metabolism including triglyceride, total cholesterol, fasting plasma glucose (FPG), serum insulin, body mass index and homeostasis model assessment-insulin resistance. Separate multiple regression analyses were performed with data from the discovery and reduplication subjects to determine whether serum osteocalcin concentration was an independent predictor of the glucose or lipid metabolism markers.

RESULTS

For the discovery-study subjects, serum osteocalcin was found to be negatively associated with weight (r=-0.08, P=0.002), BMI (-0.13, P<0.001) and FPG (r=-0.13, P=0.001). Similar results were also found in the reduplication subjects (weight: r=-0.19, P=0.016; BMI: r=-0.23, P=0.003; FPG: r=-0.28, P<0.001). In the multiple regression analysis, serum osteocalcin was revealed as a potential independent predictor for FPG (β=-0.07 and -0.210 for discovery and reduplication, respectively, P<0.01) and BMI (β=-0.127 and -0.299 for discovery and reduplication, respectively, P<0.01).

CONCLUSION

Serum osteocalcin is negatively associated with weight BMI and FPG in healthy Chinese women. Therefore, osteocalcin might contribute to obesity and diabetes.

Calorie restriction aggravated cortical and trabecular bone architecture in ovariectomy-induced estrogen-deficient rats

We hypothesized that calorie restriction (CR) and estrogen deficiency (ovariectomy [OVX]) would aggravate bone biomarkers and structural parameters in rats. Seven-week-old female Sprague-Dawley rats were randomized to sham-operated groups and fed either an ad libitum diet (SHAM-AL) or a CR diet (SHAM-CR); ovariectomy-operated groups were fed an ad libitum diet (OVX-AL) or a CR diet (OVX-CR). For 8 weeks, the OVX-AL and SHAM-AL groups were fed the same diet, whereas CR groups were fed a diet containing 50% fewer calories. Bone-related biomarkers and structural parameters (OC; deoxypyridinoline [DPD]; N-terminal telopeptide, NTx; architecture and mineralization; and microcomputed tomography images) were analyzed at the end of the experiment. The serum OC levels of calorie-restricted groups (SHAM-CR and OVX-CR) were significantly lower than those of the AL groups (SHAM-AL and OVX-AL) (P < .05). Urinary DPD levels of calorie-restricted and ovariectomized groups were higher than those of their counterparts (P < .05), whereas urinary NTx levels of calorie-restricted groups were higher than those of AL groups (P < .05). In regard to trabecular bone, the calorie-restricted and ovariectomized groups had lower values of bone volume to total volume, trabecular number, and bone mineral density, but higher values of trabecular separation than those of their counterparts (P < .05). Regarding cortical bone, the calorie-restricted groups had reduced values of bone volume, mean polar moment of inertia, and cortical thickness compared to the AL groups (P < .05). In conclusion, severe CR with or without OVX during the growth period in rats is equally detrimental to bone; CR has detrimental effects on trabecular and cortical bone; and estrogen deficiency only had an effect on trabecular bone.

Suppressed bone turnover in obesity: a link to energy metabolism? A case-control study

CONTEXT

Observations in rodents suggest that osteocalcin (OC) participates in glucose metabolism. Based on human studies, it remains unclear whether circulating OC is simply a bone turnover marker (BTM) or also a mediator in interactions between the skeleton and glucose homeostasis.

OBJECTIVE

The objective of the study was to determine the responses of BTMs, including OC, to oral glucose tolerance test (OGTT) in a case-control setting.

DESIGN AND PATIENTS

Thirty-four normoglycemic young adults [mean age 19 y (SD 2.3)] with severe childhood-onset obesity and their gender- and age-matched nonobese controls underwent a standard 2-hour OGTT.

MAIN OUTCOME MEASURES

Glucose, insulin, and six BTMs including total and carboxylated OC (cOC) were determined at baseline and at 30, 60, 90, and 120 minutes during OGTT.

RESULTS

The obese and control subjects were similar in height; the mean body mass indices were 40.4 and 21.9 kg/m(2), respectively. The homeostasis model assessment index was 2.7 times greater in the obese subjects. All BTMs, except bone-specific alkaline phophatase, were lower in the obese subjects compared with the controls: the differences at baseline were 40%, 35%, 17%, 31%, and 32% for N-terminal propeptides of type I collagen, cross-linked telopeptides of type I collagen, tartrate-resistant acid phosphatase, total OC, and carboxylated OC (P < .05 for all) after adjusting for whole-body bone area. All BTMs decreased during OGTT. The relative values for the OGTT responses for total, but not for cOC (measured as area under the curve) differed between the two groups (P = .029 and P = .139, respectively): the decrease in total OC during the OGTT was less pronounced in the obese subjects. Responses in other BTMs were similar between the groups. No associations were observed between glucose metabolism and OCs during OGTT with linear regression.

CONCLUSIONS

Bone turnover markers were substantially lower in obese subjects compared with controls. Total OC and cOC showed less pronounced decrease during the OGTT in obese subjects compared with controls, whereas other BTMs responded similarly in the two groups. The role of OC, if anything, in glucose homeostasis is indirect and may be mediated via other factors than glucose or insulin.

Reference intervals of bone turnover markers determined by using their curve-fitting valley for adult females in China

SUMMARY

The reference values for bone turnover markers (BTMs) have a significant role in the diagnosis, monitoring, and treatment of metabolic bone disease. This study proposes that the peak value of bone mineral density and the trough value for the BTM curve can be used to determine the reference range of BTM.

INTRODUCTION

The aim of this study is to determine the reference intervals of BTMs for adult females in China with an attempt to reference the peak bone mineral density (BMD) with the corresponding BTM valley.

METHODS

This study included 546 premenopausal and 394 postmenopausal women. The levels of several BTMs were determined, and the BMD was measured using a dual-energy X-ray absorptiometry.

RESULTS

The BTMs of postmenopausal women were 17-96 % higher than premenopausal women. The change of BTM with age presented an optimal goodness-of-fit according to the cubic regression model (R (2) = 0.074-0.346, all P = 0.000). All kinds of BTM levels were positively correlated with age in premenopausal women aged 27-56 years old (r = 0.167-0.502, P = 0.023-0.000). Except for uCTX, the BTM reference value determined using a curve-fitting valley was significantly lower than the reference values for premenopausal women. The BTM reference values determined in this study were also significantly different from the reference values given by the manufacturers of the reagents used.

CONCLUSIONS

This study found that the changes of level with age of BTMs in Chinese women present an optimal goodness-of-fit according to the cubic regression model. The fitting valley corresponds to the BMD fitting peak and may possibly be an effective means of determining the BTM reference intervals.

Age-related bone turnover markers and osteoporotic risk in native Chinese women

BACKGROUND

The rate of bone turnover is closely related to osteoporosis risk. We investigated the correlation between bone turnover markers and BMD at various skeletal sites in healthy native Chinese women, and to study the effect of changes in the levels of bone turnover markers on the risk of osteoporosis.

METHODS

A cross-section study of 891 healthy Chinese women aged 20-80 years was conducted. The levels of serum osteocalcin (OC), bone-specific alkaline phosphatase (BAP), serum cross-linked N-terminal telopeptides of type I collagen (sNTX), cross-linked C-terminal telopeptides of type I collagen (sCTX), urinary NTX (uNTX), urinary CTX (uCTX) and total urinary deoxypyridinoline (uDPD) were determined. BMD at the posteroanterior spine and the hip was measured using DXA.

RESULTS

Pearson's correlation coefficient found significant negative correlation between bone turnover marker and BMD T-score at different skeletal sites (r = -0.08 to -0.52, all P = 0.038-0.000). After adjustments for age and body mass index, the partial correlation coefficients between the OC, BAP, sNTX, sCTX and uCTX, and the T-scores at various skeletal sites were still significant. After adjustment of height and weight, the correlation coefficients between most BTMs and PA lumbar spine BMD were also significant. Multiple linear regression analysis showed that bone turnover markers were negative determinants of T-scores. BAP and OC accounted for 33.1% and 7.8% of the variations in the T-scores of the PA spine, respectively. Serum OC, BAP, uDPD, and sNTX accounted for 0.4-21.9% of the variations in the femoral neck and total hip T-scores. The bone turnover marker levels were grouped as per quartile intervals, and the T-scores, osteoporosis prevalence and risk were found to markedly and increase with increase in bone turnover marker levels.

CONCLUSIONS

This study clarified the relationship between bone turnover markers and osteoporosis risk in native Chinese women. Bone turnover marker levels were found to be important determinants of BMD T-scores. Furthermore, osteoporotic risk significantly increased with increase in the levels of bone turnover markers.

Age-related reference intervals for bone turnover markers from an Australian reference population

BACKGROUND

This study was performed to establish age-related serum reference intervals for procollagen type I N-propeptide (P1NP) and type I collagen C-telopeptide (CTx) in the Australian population.

METHODS

Fasting sera from 1143 males (mean age 60 years; range 20-97 years) and 1246 females (mean age 53 years; range 20-93 years) who participated in the Geelong Osteoporosis Study were analysed for CTx and P1NP using the automated Roche Modular Analytics E170 analyser.

RESULTS

Optimal age-related reference intervals were based on the central 90% of the distribution. The male CTx reference interval was divided into three age groups. For men aged 25 to 40 years, the interval was 170-600 ng/L; 40 to 60 years, the interval was 130-600 ng/L; and for men aged greater 60 years the interval was 100-600 ng/L. For P1NP the male reference interval was 15-80 μg/L for men aged between 25 to 70 years. In men greater than 70 years of age values were higher possibly due to increased bone turnover. High values are frequently seen for both CTx and P1NP in males aged younger than 25 years. This is probably due to bone growth that is not completely finalised. The female CTx reference interval was divided into four age groups. For women aged less than 30 years, the interval was 150-800 ng/L; 30-39 years, the interval was 100-700 ng/L; 40-49 years, the interval was 100-600 ng/L; and for women aged 50 years or more the interval was 100-700 ng/L. The female P1NP reference interval was divided into four age groups. For women aged less than 30 years, the interval was 25-90 μg/L; 30-39 years, the interval was 15-80 μg/L; 40-49 years, the interval was 15-60 μg/L; and for women aged 50-69 years the interval was 15-75 μg/L. In women greater than 70 years of age values were higher possibly due to increased bone turnover.

CONCLUSION

Values obtained from this large study provide sound age-related reference intervals for serum P1NP and CTx values in the Australian population.

Bisphosphonate drug holiday: choosing appropriate candidates

Osteoporosis related fractures contribute to morbidity and mortality in U.S. patients, placing a heavy financial burden on society. Randomized clinical trials involving over 30,000 subjects have established bisphosphonates' efficacy in reducing the incidence of fragility fractures. However, as bisphosphonates are retained for years in the skeleton, reports of adverse events from prolonged use are surfacing in the literature, namely, esophageal cancer, atrial fibrillation, osteonecrosis of the jaw, and atypical fracture development. The concept of a drug holiday has been proposed to potentially reduce incidence of these adverse events. This review will highlight the benefits and risks of bisphosphonate therapy and discuss the extension data available from the bisphosphonate trials. As randomized clinical trial evidence is not yet available on who may qualify for drug holiday, this review will provide suggestions for clinicians on identification of possible candidates and monitoring during a bisphosphonate drug holiday.

Polymorphisms in the inflammatory genes CIITA, CLEC16A and IFNG influence BMD, bone loss and fracture in elderly women

Osteoclast activity and the fine balance between bone formation and resorption is affected by inflammatory factors such as cytokines and T lymphocyte activity, mediated by major histocompatibility complex (MHC) molecules, in turn regulated by the MHC class II transactivator (MHC2TA). We investigated the effect of functional polymorphisms in the MHC2TA gene (CIITA), and two additional genes; C-type lectin domain 16A (CLEC16A), in linkage disequilibrium with CIITA and Interferon-γ (IFNG), an inducer of CIITA; on bone density, bone resorption markers, bone loss and fracture risk in 75 year-old women followed for up to 10 years (OPRA n = 1003) and in young adult women (PEAK-25 n = 999). CIITA was associated with BMD at age 75 (lumbar spine p = 0.011; femoral neck (FN) p = 0.049) and age 80 (total body p = 0.015; total hip p = 0.042; FN p = 0.028). Carriers of the CIITA rs3087456(G) allele had 1.8–3.4% higher BMD and displayed increased rate of bone loss between age 75 and 80 (FN p = 0.013; total hip p = 0.030; total body p = 3.8E⁻⁵). Despite increasing bone loss, the rs3087456(G) allele was protective against incident fracture overall (p = 0.002), osteoporotic fracture and hip fracture. Carriers of CLEC16A and IFNG variant alleles had lower BMD (p<0.05) and ultrasound parameters and a lower risk of incident fracture (CLEC16A, p = 0.011). In 25-year old women, none of the genes were associated with BMD. In conclusion, variation in inflammatory genes CIITA, CLEC-16A and INFG appear to contribute to bone phenotypes in elderly women and suggest a role for low-grade inflammation and MHC class II expression for osteoporosis pathogenesis.

National Bone Health Alliance Bone Turnover Marker Project: current practices and the need for US harmonization, standardization, and common reference ranges

This position paper reviews how the National Bone Health Alliance (NBHA) will execute a project to help assure health professionals of the clinical utility of bone turnover markers; the current clinical approaches concerning osteoporosis and the status and use of bone turnover markers in the USA; the rationale for focusing this effort around two specific bone turnover markers; the need to standardize bone marker sample collection procedures, reference ranges, and bone turnover marker assays in clinical laboratories; and the importance of harmonization for future research of bone turnover markers.

INTRODUCTION

Osteoporosis is a major global health problem, with the prevalence and incidence of osteoporosis for at-risk populations estimated to be 44 million Americans. The potential of bone markers as an additional tool for health care professionals to improve patient outcomes and impact morbidity and mortality is crucial in providing better health care and addressing rising health care costs. This need to advance the field of bone turnover markers has been recognized by a number of organizations, including the International Osteoporosis Foundation (IOF), National Osteoporosis Foundation, International Federation of Clinical Chemistry, and Laboratory Medicine (IFCC), and the NBHA.

METHODS

This position paper elucidates how this project will standardize bone turnover marker sample collection procedures in the USA, establish a USA reference range for one bone formation (serum procollagen type I N propeptide, s-PINP) and one bone resorption (serum C-terminal telopeptide of type I collagen, s-CTX) marker, and standardize bone turnover marker assays used in clinical laboratories. This effort will allow clinicians from the USA to have confidence in their use of bone turnover markers to help monitor osteoporosis treatment and assess future fracture risk. This project builds on the recommendations of the IOF/IFCC Bone Marker Standards Working Group by developing USA reference standards for s-PINP and s-CTX, the markers identified as most promising for use as reference markers.

RESULTS

The goals of this project will be realized through the NBHA and will include its governmental, academic, for-profit, and non-profit sector stakeholders as well as major academic and commercial laboratories. Upon completion, a parallel effort will be pursued to make bone turnover marker measurements reliable and accepted by all health care professionals for facilitating treatment decisions and ultimately be reimbursed by all health insurance payers.

CONCLUSIONS

Successful completion of this project will help assure health professionals from the USA of the clinical utility of bone turnover markers and ties in with the parallel effort of the IOF/IFCC to develop worldwide bone turnover reference ranges.

Matrix metalloproteinase-13 is required for osteocytic perilacunar remodeling and maintains bone fracture resistance

Like bone mass, bone quality is specified in development, actively maintained postnatally, and disrupted by disease. The roles of osteoblasts, osteoclasts, and osteocytes in the regulation of bone mass are increasingly well defined. However, the cellular and molecular mechanisms by which bone quality is regulated remain unclear. Proteins that remodel bone extracellular matrix, such as the collagen-degrading matrix metalloproteinase (MMP)-13, are likely candidates to regulate bone quality. Using MMP-13-deficient mice, we examined the role of MMP-13 in the remodeling and maintenance of bone matrix and subsequent fracture resistance. Throughout the diaphysis of MMP-13-deficient tibiae, we observed elevated nonenzymatic cross-linking and concentric regions of hypermineralization, collagen disorganization, and canalicular malformation. These defects localize to the same mid-cortical bone regions where osteocyte lacunae and canaliculi exhibit MMP-13 and tartrate-resistant acid phosphatase (TRAP) expression, as well as the osteocyte marker sclerostin. Despite otherwise normal measures of osteoclast and osteoblast function, dynamic histomorphometry revealed that remodeling of osteocyte lacunae is impaired in MMP-13(-/-) bone. Analysis of MMP-13(-/-) mice and their wild-type littermates in normal and lactating conditions showed that MMP-13 is not only required for lactation-induced osteocyte perilacunar remodeling, but also for the maintenance of bone quality. The loss of MMP-13, and the resulting defects in perilacunar remodeling and matrix organization, compromise MMP-13(-/-) bone fracture toughness and postyield behavior. Taken together, these findings demonstrate that osteocyte perilacunar remodeling of mid-cortical bone matrix requires MMP-13 and is essential for the maintenance of bone quality.

The levels of bone turnover markers in Chinese postmenopausal women: Peking Vertebral Fracture study

OBJECTIVE

The aim of this study was to evaluate serum N-aminoterminal propeptide of type I collagen (P1NP), C-terminal telopeptide of type I collagen (β-CTX), and vitamin D status in healthy Chinese postmenopausal women. The study was also designed to investigate their possible relationships with osteoporosis phenotypes.

METHODS

A community-based population of 1,724 postmenopausal women in Beijing was randomly selected. Serum bone turnover markers and 25-hydroxyvitamin D [25(OH)D] were tested by an automated Roche electrochemiluminescence system. Dual-energy x-ray absorptiometry was used to measure bone mineral density (BMD).

RESULTS

The mean (SD) values of serum β-CTX and P1NP were 0.439 (0.210) and 56.7 (27.9) ng/mL, respectively. The 25(OH)D level of postmenopausal women in Beijing was remarkably low (13.2 ± 5.4 ng/mL). Serum β-CTX and P1NP levels were negatively correlated with BMDs of lumbar spine, femoral neck, and total hip (all P < 0.01). The cubic regression model better fitted the relationships of BMD and bone turnover markers. Serum β-CTX levels were significantly higher in women with sustained osteoporotic fracture or vertebral fracture (P = 0.006 and 0.012, respectively). No association between P1NP and fracture or vertebral fracture was detected. The same situation applied to 25(OH)D. 25(OH)D was negatively correlated with β-CTX and P1NP (r = -0.073 and -0.088, P = 0.002 and <0.001, respectively).

CONCLUSIONS

Serum β-CTX and P1NP levels were negatively correlated with BMD. β-CTX was significantly higher in postmenopausal women with sustained fracture or vertebral fracture. Vitamin D deficiency was highly prevalent in postmenopausal women in Beijing.

Reduction of urinary levels of N-telopeptide correlates with treatment compliance in women with postmenopausal osteoporosis receiving alendronate

OBJECTIVE

The aim of this study was to assess the factors associated with the effectiveness of treatment with alendronate (ALN) quantified by a reduction in urinary excretion of N-telopeptide (NTx).

METHODS

The study is an observational, prospective, multicenter trial, with a 6-month follow-up. Postmenopausal osteoporotic women (densitometric criteria), who initiated treatment with ALN (70 mg/weekly) without previous treatment with antiresorptive agents (12 month) and calcitonin (6 month), were included. The assessment of NTx levels (nmol bone collagen equivalents/mmol creatinine) in the urine was performed at baseline and after completion of follow-up. A logistic regression model included "achieving a reduction in urinary NTx of at least 30% (minimal clinically significant change [MCSC])" as a dichotomous dependent variable and the following as independent variables: baseline urinary NTx levels, treatment compliance, years since diagnosis of menopause, ALN treatment duration, and treatment with calcium and vitamin D. Treatment compliance was assessed as the percentage of days of medication prescribed as a function of the time between the beginning and end of treatment. Good compliance was defined as a percentage between 80% and 120%.

RESULTS

The variables that reached statistical significance were baseline urinary NTx values (odds ratio, 1.052; 95% CI, 1.025-1.079) and compliance (odds ratio, 3.9; 95% CI, 1.5-10.1). Therefore, the women with good treatment compliance were almost 4 times more likely to achieve an MCSC in NTx levels, and the raise in one unit of urinary NTx baseline values increased by 5% of the probability of achieving MCSC.

CONCLUSIONS

Treatment with ALN (70 mg/week) in women with postmenopausal osteoporosis effectively reduces the urinary excretion of the bone turnover biomarker NTx. The probability of achieving a clinically significant reduction is greater in those women with higher baseline levels of NTx and in women who comply with treatment.

Vitamin K-dependent carboxylation of osteocalcin: friend or foe?

Osteocalcin originates from osteoblastic synthesis and is deposited into bone or released into circulation, where it correlates with histological measures of bone formation. The presence of 3 vitamin K-dependent γ carboxyglutamic acid residues is critical for osteocalcin's structure, which appears to regulate the maturation of bone mineral. In humans, the percentage of the circulating osteocalcin that is not γ-carboxylated (percent ucOC) is used as a biomarker of vitamin K status. In contrast, when ucOC is not corrected for total osteocalcin, the interpretation of this measure is confounded by osteoblastic activity, independent of vitamin K. Observational studies using percent ucOC have led to the conclusion that vitamin K insufficiency leads to age-related bone loss. However, clinical trials do not provide overall support for the suggestion that vitamin K supplementation of the general population will reduce bone loss or fracture risk. More recently, results from in vitro and in vivo studies using animal models indicate that ucOC is an active hormone with a positive role in glucose metabolism. By inference, vitamin K, which decreases ucOC, would have a detrimental effect. However, in humans this hypothesis is not supported by the limited data available, nor is it supported by what has been established regarding osteocalcin chemistry. In summary, the specific function of osteocalcin in bone and glucose metabolism has yet to be elucidated.

Is there a place for bone turnover markers in the assessment of osteoporosis and its treatment?

As populations age, the number of osteoporotic fractures will increase. Bone mineral density (BMD) measurement remains the major way to diagnose osteoporosis and to indicate therapy. The FRAX tool, based on clinical risk factors, estimates the 10-year risk of hip and major osteoporotic fractures. The association of BMD and FRAX measurements has improved the identification of patients who are most at risk. However, some patients can still be overlooked and denied therapy. It is sound that adding the measure of bone turnover markers to the former risk factors and their follow-up during therapy could best address the efficacy of treatment of osteoporosis. Whether this behavior is cost-effective remains to be settled.

The effect of oral glucose tolerance test on serum osteocalcin and bone turnover markers in young adults

Osteocalcin (OC) is an osteoblast-derived protein implicated in the regulation of glucose tolerance and energy metabolism. This endocrine function has been suggested to be exerted via its undercarboxylated form, which has been shown to induce expression of adiponectin, insulin, and islet cell proliferation in mice. Furthermore, insulin has recently been shown to regulate the biological activity of OC in bone. Our aim was to explore the association between glucose and bone metabolism by evaluating the effect of a standard 75 g oral glucose tolerance test (OGTT) on serum OC, carboxylated OC (cOC) and bone-turnover markers (BTMs) C terminal telopeptide (βCTX-I) and N terminal propeptide (PINP) of type I collagen and tartrate-resistant acid phosphatase 5b (TRACP5b). Serum samples collected at 0 and at 120 min were analyzed in a cohort of normoglycemic young adults (n = 23, mean age 23.6 years). During OGTT a significant decrease was observed in all BTMs (P < 0.001 for all variables). The median decreases from 0 to 120 min for OC, cOC, βCTX-I, PINP, and TRACP5b were -32.1% (-37.9 to -19.6), -34.4% (-39.8 to -22.2), -61.4% (-68.5 to -53.0), -26.8% (-33.2 to -19.2), and -44.5% (-48.3 to -40.2), respectively. A strong association between the changes in OC and cOC was observed (r = 0.83, P < 0.001). The decrease in PINP was associated with changes in OC, whereas the changes in βCTX-I and TRACP5b were not associated with decreases in OC or cOC. The observed OGTT-induced changes in bone-derived proteins were partially independent of each other and potentially mediated by different mechanisms.

Suitability of tartrate-resistant acid phosphatase type 5b as a screening marker for bone mineral density in community-dwelling elderly individuals

Osteoporosis is a common disorder in aging populations that imposes considerable health problems. Tartrate-resistant acid phosphatase type 5b (TRAP-5b) is derived from osteoclasts, and is involved in normal bone homeostasis. Recently, a novel assay system for TRAP-5b, the fragments absorbed immunocapture enzymatic assay method, has been developed. To evaluate the suitability of TRAP-5b as a screening marker for bone mineral density (BMD), we explored the correlations between serum TRAP-5b concentrations and laboratory findings, body mass index, or BMD in 462 community-dwelling elderly individuals (249 men and 213 women, age 73.4±6.5 years) who participated in a regular medical screening program. By multivariate linear regression analysis adjusted for confounding factors, TRAP-5b was significantly correlated with body mass index (β=-0.005, p=0.043), alkaline phosphatase, a marker for osteoid formation and calcification (β=0.001, p<0.001), and triglyceride (β=-0.097, p=0.016) in men, and with body mass index (β=-0.009, p=0.025), alkaline phosphatase (β=0.001, p<0.001), calcium (β=-0.059, p=0.039), and bone trabecular area ratio (β=-0.47, p=0.025) in women. In conclusion, the elevated serum level of TRAP-5b is independently correlated with the decreased BMD in women, but not in men. Because measurement of TRAP-5b is not affected by food intake, and blood samples can be collected at any time of the day, we suggest the suitability of serum TRAP-5b as a simple marker for the evaluation of BMD in women.

The relationship between bone turnover markers and BMD decreasing rates in Chinese middle-aged women

BACKGROUND

The relationship between bone turnover markers (BTMs) and BMD decreasing rate (BDR) in Chinese women is unclear. Wu investigated the relationship between (BTMs) and BDR at various skeletal sites in Chinese middle-aged women.

METHODS

A cross-section study of 555 healthy Chinese women over 35-60years of age. BMD at posteroanterior spine, the left hip, and the left forearm were measured with a DXA. Levels of serum osteocalcin (OC), bone-specific alkaline phosphatase (BAP), cross-linked N-terminal telopeptides of type I collagen (sNTX) and total urinary deoxypyridinoline (uDPD) were determined.

RESULTS

BDR at various skeletal sites had significant negative correlation with serum OC(r=-0.395 to -0.530), BAP(r=-0.297 to -0.486), and sNTX(r=-0.207 to -0.272). After adjustment of age and weight, serum OC, BAP, and sNTX rather than total uDPD still exhibited significant correlations with BDR. Stepwise regression analyses showed that, serum OC and BAP were the significantly negative determinants of BDR. Between 4.7-27.7% and 1.2-16.1% of the changes in BDR were determined by serum OC and BAP, respectively. However, sNTX and total uDPD had no significant effect on BDR at various skeletal sites.

CONCLUSIONS

This study indicated the correlation between BTMs and early-stage BDR in Chinese middle-aged women and suggested that serum OC and BAP, rather than sNTX and total uDPD, are the key determining factors of early BMD decreases.

Prediction of bone loss in elderly female subjects by MR perfusion imaging and spectroscopy

OBJECTIVE

To determine whether MR perfusion indices or marrow fat content at baseline can predict areal bone mineral density (BMDa) loss.

METHODS

Repeat dual x-ray absorptiometry (DXA) of the hip was performed in female subjects at 2 years (n = 52) and 4 years (n = 45) following baseline MR perfusion imaging and spectroscopy of the hip.

RESULTS

Percentage reduction in femoral neck BMDa at 4 years post-baseline was greater in subjects with below median acetabulum enhancement slope (E(slope)) (-5.6 ± 1.2 Vs -1.1 ± 1.2 (mean ± standard error) p = 0.014) or muscle maximum enhancement (E(max)) (-5.7 ± 1.2 Vs -0.23 ± 1.2, p = 0.009) after adjusting for baseline co-variables. Baseline MR parameters correlated with reduction in BMDa at 4 years (acetabulum E(slope) r = 0.517, p = 0.0003; muscle E(max) r = 0.306, p = 0.043) as well as traditionally applied clinical risk factors. Acetabulum E(slope), femoral neck E(max) and marrow fat content at baseline had sensitivities of 89%, 81% and 72% respectively at distinguishing between fast (>1%/annum) (n = 18) and slow (<1%/annum) (n = 27) BMD losers.

CONCLUSION

Elderly female subjects with reduced perfusion indices at baseline had increased femoral neck bone loss at 4 years. Selected perfusion indices and marrow fat content have a moderate to high sensitivity in discriminating between fast and slow bone losers.

Effect of precision on longitudinal follow-up of bone mineral density measurements in elderly women and men

Precision error of dual-energy X-ray absorptiometry exceeds the expected annual rate of bone loss in the elderly. The capacity to detect changes in areal bone mineral density (aBMD; g/cm(2)) over a 5-yr period was assessed. Six hundred ninety-one women, 75.2 (0.1)yr, from the Malmö OPRA-study, were measured using Lunar DPX-L (GE Lunar, Madison, WI), and 211 men, 74.7 (3.2)yr, from the Malmö Mr Os-study, were measured using Lunar Prodigy (GE Lunar) with follow-up 5 yr later. Precision error was determined with 30 degrees of freedom. Least significant change (LSC, i.e., 2.77 × precision error) was calculated. Women's precision errors (g/cm(2)) for DPX-L were 0.028 (total hip [TH]) and 0.016 (lumbar spine [LS]), and for Prodigy, they were 0.009 (TH) and 0.039 (LS). In men, corresponding results for Prodigy were 0.014 and 0.031. In women, 41% and in men, 39% had aBMD changes exceeding the LSC at TH. Follow-up intervals (i.e., LSC/median rate of aBMD change) for both women and men were 8 yr (TH) and 13 yr (LS). Based on Prodigy precision data, follow-up intervals for women were 3 and 32 yr at TH and LS. In summary, several years were needed to detect change. Only when a high rate of bone loss is suspected, a short follow-up time is possible, in elderly persons.

Polymorphisms in the macrophage migration inhibitory factor gene and bone loss in postmenopausal women

Osteoporosis is a severe condition in postmenopausal women and a common cause of fracture. Osteoporosis is a complex disease with a strong genetic impact, but susceptibility is determined by many genes with modest effects and environmental factors. Only a handful of genes consistently associated with osteoporosis have been identified so far. Inflammation affects bone metabolism by interfering with the interplay between bone resorption and formation, and many inflammatory mediators are involved in natural bone remodeling. The cytokine macrophage migration inhibitory factor (MIF) has been shown to affect bone density in rodents, and polymorphisms in the human MIF promoter are associated with inflammatory disorders such as rheumatoid arthritis. We investigated the association of polymorphisms in the MIF gene with bone mineral density (BMD) and bone loss in 1002 elderly women using MIF promoter polymorphisms MIF-CATT(5-8) and rs755622(G/C) located -794 and -173 bp upstream of the transcriptional start site. Bone loss was estimated both by the change in BMD over 5 years and by the levels of bone resorption markers in serum measured at four occasions during a 5-year period. The MIF-CATT(7)/rs755622(C) haplotype was associated with increased rate of bone loss during 5 years at the femoral neck (p<0.05) and total hip (p<0.05). In addition, the MIF-CATT(7)/rs755622(C) haplotype carriers had higher levels of the bone turnover marker serum C-terminal cross-linking telopeptide of type I collagen (S-CTX-I, p<0.01) during the 5 year follow-up period. There was no association between MIF-CATT(7)/rs755622(C) and baseline BMD at femoral neck, total hip or lumbar spine. We conclude that MIF promoter polymorphisms have modest effects on bone remodeling and are associated with the rate of bone loss in elderly women.

Successes achieved and challenges ahead in translating biomarkers into clinical applications

Biomarkers are important tools for identifying and stratifying diseases, predicting their progression and determining the effectiveness, safety, and doses of therapeutic interventions. This is important for common chronic diseases such as diabetic nephropathy, osteoporosis, and rheumatoid arthritis which affect large numbers of patients worldwide. This article summarizes the current knowledge of established and novel biomarkers for each of these diseases as presented at the 2008 AAPS/ACCP joint symposium "Success Achieved and Challenges Ahead in Translating Biomarkers into Clinical Applications," in Atlanta, Georgia. The advantages and disadvantages of various proteomic, metabolomic, genomic, and imaging biomarkers are discussed in relation to disease diagnosis and stratification, prognosis, drug development, and potential clinical applications. The use of biomarkers as a means to determine therapeutic interventions is also considered. In addition, we show that biomarkers may be useful for adapting therapies for individual needs by allowing the selection of patients who are most likely to respond or react adversely to a particular treatment. They may also be used to determine whether the development of a novel therapy is worth pursuing by informing crucial go/no go decisions around safety and efficacy. Indeed, regulatory bodies now suggest that effective integration of biomarkers into clinical drug development programs is likely to promote the development of novel therapeutics and more personalized medicine.

The effect of a fortified milk drink on vitamin D status and bone turnover in post-menopausal women from South East Asia

Calcium and vitamin D are essential for bone growth; milk is an appropriate vehicle to be fortified with calcium, vitamin D and other minerals. The purpose of the current study was to compare the effect of supplementing with a high calcium milk drink with added vitamin D, magnesium and zinc (HCM) versus a placebo drink on serum parathyroid hormone (PTH) and vitamin D status as well as markers of bone formation/resorption in postmenopausal women living in South East Asia (Jakarta, Indonesia and Manila, the Philippines) over a period of 4 months. Calcium intake at baseline was 237 mg (median; 176-316, interquartile range) for Indonesia and 353 mg (median; 222-480, interquartile range) for the Filipino women per day. Fortified milk supplementation reduced the percentage of women that were insufficient in 25 (OH) vitamin D(3) (<50 nmol/L) from 70% to 22% in the Indonesian women and 20% to 0% in the Filipino women. Fortified milk supplementation significantly reduced parathyroid hormone levels (PTH) by week 2 (22% and 11%), C-telopeptide of type I collagen (CTX) by week 2 (34% and 27%), osteocalcin (OC) by week 8 (18% and 25%) and procollagen type I N-propeptide (PINP) by week 8 (15% and 21%), in women from Indonesia and the Philippines, respectively. Thus, the HCM intervention was able to significantly improve vitamin D status, lower PTH levels and reduce bone turnover in two groups of South East Asian women.

Randomized biomarker trial of anastrozole or low-dose tamoxifen or their combination in subjects with breast intraepithelial neoplasia

PURPOSE

In the Anastrozole, Tamoxifen Alone or in Combination trial, the combination arm was inferior to anastrozole alone in terms of disease-free survival possibly due to an adverse pharmacokinetic interaction or a predominant estrogenic effect of tamoxifen under estrogen deprivation. We assessed whether the addition of a lower dose of tamoxifen influenced anastrozole bioavailability and favorably modulated biomarkers of bone fracture, breast cancer, cardiovascular disease, and endometrial cancer risk. The influence of CYP2D6 genotype on tamoxifen effects was also determined.

EXPERIMENTAL DESIGN

Seventy-five postmenopausal women with breast intraepithelial neoplasia were randomly allocated to either 1 mg/d anastrozole or 10 mg/wk tamoxifen or their combination for 12 months. Study endpoints were plasma drug concentrations and changes of C-telopeptide, osteocalcin, estradiol/sex hormone binding globulin (SHBG) ratio, estrone sulfate, insulin-like growth factor-I (IGF-I)/insulin-like growth factor binding protein-3 (IGFBP-3), C-reactive protein, antithrombin-III, endometrial Ki-67 expression, and thickness.

RESULTS

Anastrozole concentrations were not affected by the combination with low-dose tamoxifen, whereas endoxifen levels were lower in poor CYP2D6 metabolizers. C-telopeptide increased by 20% with anastrozole and decreased by 16% with tamoxifen and by 7% with their combination (P < 0.001); osteocalcin showed similar changes. Compared with anastrozole, the combination arm showed lower IGF-I/IGFBP-3 levels (-17% versus -9%; P = 0.004) and lower estradiol/SHBG and estrone sulfate reductions (-15% versus -29% and -30% versus 38%, respectively). However, IGF-I/IGFBP-3 and estradiol/SHBG did not decrease in poor CYP2D6 metabolizers. Endometrial thickness was not greater in the combination than in the anastrozole arm.

CONCLUSIONS

The addition of a weekly tamoxifen administration did not impair anastrozole bioavailability and modulated favorably its safety profile, providing the rationale for further studies.

Bone markers in osteoporosis

Current biological markers of bone turnover have proven useful in improving fracture risk assessment and monitoring treatment efficacy in postmenopausal osteoporosis. Recent developments in the field of bone markers include 1) identification of new biochemical markers providing additional information on the complex pathways leading to bone fragility; 2) application of novel technologies such as proteomics for the discovery of novel markers; 3) automation and multiplexing for improving analytical performance and convenience; and 4) refinement of the clinical interpretation of markers. Currently, however, for the management of individual patients, their most established application is to monitor treatment efficacy and possibly to improve fracture risk assessment. The role of bone markers for improving adherence to therapy will need to be investigated in further studies. This brief review discusses these novel technological developments and the recent clinical data on the use of established and new markers in postmenopausal osteoporosis.

Skeletal and hormonal responses to sunlight deprivation in Antarctic expeditioners

Serum 25(OH)D levels decline without sunlight exposure. We studied 120 expeditioners to Antarctica to determine the skeletal and hormonal responses to sunlight deprivation. With emerging vitamin D insufficiency, serum calcium decreased, PTH increased, and bone loss at the proximal femur was observed. Baseline serum 25(OH)D levels >100 nmol/L prevented vitamin D insufficiency.

INTRODUCTION

Vitamin D stores deplete without adequate sunlight exposure unless supplementation is provided. We studied 120 healthy adults who spent a year in Antarctica as a model for sunlight deprivation to define the timing and magnitude of the skeletal and hormonal responses to emerging vitamin D insufficiency.

METHODS

Fasting blood samples were assessed at baseline, 6 and 12 months for serum 25-hydroxyvitamin D (25(OH)D), osteocalcin (OC), bone formation (P1NP) and resorption (CTx), PTH and calcium. Lumbar spine and proximal femur BMD was measured using DXA. Differences over time were determined using repeated measures ANOVA. Percent changes were expressed as (Delta value/(value A + value B)/2) x 100. Relationships between outcome measures were determined using Spearman's correlations.

RESULTS

Vitamin D insufficiency (<50 nmol/L) was observed in 85% of expeditioners by 6 months when serum calcium decreased and PTH increased (p < 0.01). By 12 months, OC increased by 7.4 +/- 3.0% (p < 0.05), and BMD decreased by 1.0 +/- 2.0% at the total proximal femur (p < 0.05). For those with vitamin D sufficiency at baseline (>50 nmol/L), sunlight deprivation produced vitamin D insufficiency within 4 months unless baseline values were >100 nmol/L.

CONCLUSION

Supplementation may be necessary for expeditioners with limited access to UV light.

Bone turnover markers are correlated with quantitative ultrasound of the calcaneus: 5-year longitudinal data

SUMMARY

Associations between bone turnover markers and calcaneal ultrasound (quantitative ultrasound, QUS) were studied in a population-based sample of 810 elderly women. Baseline bone turnover markers correlated with baseline QUS as well as with 5-year prospective changes in QUS.

INTRODUCTION

Bone turnover markers are associated with areal bone mineral density, but the knowledge on the association with QUS is limited.

METHODS

Eight hundred ten women, all 75 years old, were investigated at baseline. Five hundred six completed a 5-year follow-up. Bone turnover markers and calcaneal QUS [speed of sound (SoS), broadband ultrasound attenuation (BUA), stiffness] were investigated at baseline. QUS was investigated at follow-up.

RESULTS

All bone turnover markers were correlated with baseline QUS [standardized regression (Beta(std)) values from -0.07, p < 0.05 to -0.23, p < 0.001], with the exception of bone-specific alkaline phosphatase (S-Bone ALP) which was not correlated with BUA and stiffness index. When the correlations between baseline bone turnover markers and 5-year changes in QUS were analyzed, three serum osteocalcins were correlated with changes of SoS and stiffness index (Beta(std) = -0.11, p < 0.05 to -0.17, p < 0.001). Also S-CTX-I correlated with changes of SoS and stiffness index (Beta(std) = -0.10 and -0.09, respectively, p < 0.05). S-TRACP5b, urinary deoxypyridinoline/crea, and U-MidOC/crea correlated with changes of SoS (Beta(std) = -0.10 and p < 0.05 for all). S-Bone ALP did not correlate with change of QUS. None of the bone turnover markers correlated with changes of BUA.

CONCLUSIONS

Bone turnover markers correlate with concomitantly assessed QUS as well as with longitudinal change in QUS.

Bone turnover markers are correlated with total skeletal uptake of 99mTc-methylene diphosphonate (99mTc-MDP)

Background

Skeletal uptake of ^99mTc labelled methylene diphosphonate (^99mTc-MDP) is used for producing images of pathological bone uptake due to its incorporation to the sites of active bone turnover. This study was done to validate bone turnover markers using total skeletal uptake (TSU) of ^99mTc-MDP.

Methods

22 postmenopausal women (52–80 years) volunteered to participate. Scintigraphy was performed by injecting 520 MBq of ^99mTc-MDP and taking whole body images after 3 minutes, and 5 hours. TSU was calculated from these two images by taking into account the urinary loss and soft tissue uptake. Bone turnover markers used were bone specific alkaline phosphatase (S-Bone ALP), three different assays for serum osteocalcin (OC), tartrate resistant acid phosphatase 5b (S-TRACP5b), serum C-terminal cross-linked telopeptides of type I collagen (S-CTX-I) and three assays for urinary osteocalcin (U-OC).

Results

The median TSU of ^99mTc-MDP was 23% of the administered activity. All bone turnover markers were significantly correlated with TSU with r-values from 0.52 (p = 0.013) to 0.90 (p < 0.001). The two resorption markers had numerically higher correlations (S-TRACP5b r = 0.90, S-CTX-I r = 0.80) than the formation markers (S-Total OC r = 0.72, S-Bone ALP r = 0.66), but the difference was not statistically significant. TSU did not correlate with age, weight, body mass index or bone mineral density.

Conclusion

In conclusion, bone turnover markers are strongly correlated with total skeletal uptake of ^99mTc-MDP. There were no significant differences in correlations for bone formation and resorption markers. This should be due to the coupling between formation and resorption.

The bone marker plot: an innovative method to assess bone turnover in women

BACKGROUND

Biochemical markers of bone turnover reflect the resorptive and reconstructive effects that act on the skeleton. Although elevated markers are commonly interpreted as a sign of an increased turnover rate, the balance between bone resorption and formation is mostly neglected. We introduce a graphic report combining both complementary processes.

MATERIALS AND METHODS

Bone turnover markers were measured in 599 women (aged 25-74 years). To set up reference ranges, 269 from 599 women were selected because of having T-scores > -1 and inconspicuous basic laboratory data. Concentrations of resorption and formation markers were mathematically transformed to build up plots with four fields, symbolizing fast and slow resorption and fast and slow formation processes. The reference data of bone turnover were represented by a 95% confidence ellipse. For individual marker plots, we converted data of bone turnover markers from therapy follow-up profiles of patients in a similar manner.

RESULTS

In pre-, peri- and postmenopausal women (n= 190, 39 +/- 6 years; n= 35, 51 +/- 6 years; n= 44, 55 +/- 5 years, respectively), the medians of the bone resorption marker CrossLaps and of the bone formation markers osteocalcin and aminoterminal propeptide of type I procollagen were 0.13/0.16/0.22 ng mL(-1), 21/21/25 ng mL(-1) and 36/35/45 ng mL(-1), respectively. In postmenopausal women, the marker plots revealed a shift towards accelerated bone resorption. A discrimination from osteopenic women (n= 138) failed.

CONCLUSION

The proposed marker plot facilitates the intuitive perception of bone turnover in individual patients as well as in patient groups by a synopsis of the balance between bone formation and resorption with the rate of these processes.