Association of bone turnover markers with mortality in men referred to coronary angiography

Pathophysiology and Therapeutic Management of Bone Loss in Patients with Critical Illness

Patients with critical illnesses are at higher risk of comorbidities, which can include bone mineral density loss, bone turnover marker increase, and fragility fractures. Patients admitted to intensive care units (ICUs) have a higher risk of bone fractures. Since hypermetabolism is a characteristic of ICU patients, such patients are often rapidly affected by systemic deterioration, which often results in systemic wasting disease. Major risk factors for ICU-related bone loss include physical restraint, inflammation, neuroendocrine stress, malnutrition, and medications. A medical history of critical illness should be acknowledged as a risk factor for impaired bone metabolism. Bone loss associated with ICU admission should be recognized as a key component of post-intensive care syndrome, and further research that focuses on treatment protocols and prevention strategies is required. Studies aimed at maintaining gut integrity have emphasized protein administration and nutrition, while research is ongoing to evaluate the therapeutic benefits of anti-resorptive agents and physical therapy. This review examines both current and innovative clinical strategies that are used for identifying risk factors of bone loss. It provides an overview of perioperative outcomes and discusses the emerging novel treatment modalities. Furthermore, the review presents future directions in the treatment of ICU-related bone loss.

Associations of Serum 25(OH)D, PTH, and β-CTX Levels with All-Cause Mortality in Chinese Community-Dwelling Centenarians

This longitudinal cohort study explored the associations of 25-hydroxyvitamin D [25(OH)D], parathyroid hormone (PTH), and β-C-terminal telopeptide of type 1 collagen (β-CTX) levels with all-cause mortality in centenarians. The study included 952 centenarians (81.4% female). During a median follow-up of 32 months, 752 (78.9%) centenarians died. The estimated 1-year, 3-year, and 5-year survival rates were 80.0%, 45.7%, and 23.6%, respectively. The association of mortality with 25(OH)D was linear, whereas the associations with PTH and β-CTX were J-shaped, with a lower risk below the median levels. Compared with 25(OH)D of ≥30 ng/mL, 25(OH)D < 30 ng/mL was associated with increased mortality (HR 1.52, 95% CI 1.24−1.86, p < 0.001). Compared with PTH of ≤65 pg/mL, PTH > 65 pg/mL was associated with increased mortality (HR 1.30, 95% CI 1.08−1.56, p = 0.005). Compared with β-CTX of <0.55 ng/mL, β-CTX ≥ 0.55 ng/mL was associated with increased mortality (HR 1.30, 95% CI 1.10−1.54, p = 0.002). A higher β-CTX level (even in the clinical reference range of 0.55−1.01 ng/mL) was associated with increased mortality (HR 1.23, 95% CI 1.04−1.47, p = 0.018). Centenarians with 25(OH)D < 30 ng/mL, PTH > 65 pg/mL, and β-CTX ≥ 0.55 ng/mL had a 2.77-fold (95% CI 1.99−3.85, p < 0.001) increased risk of mortality when compared with those with 25(OH)D of >30 ng/mL, PTH < 65 pg/mL, and β-CTX < 0.55 ng/mL. Lower serum 25(OH)D and higher PTH and β-CTX were independently correlated with increased all-cause mortality in Chinese community-dwelling centenarians.

Bone Turnover Markers Including Undercarboxylated Osteocalcin Are Associated With Mortality Risk in Older Men

Osteocalcin in its undercarboxylated form (ucOC) may influence diabetes risk; however, its relationship with all-cause and cause-specific mortality is unclear. Whether other bone turnover markers (BTMs) are associated with mortality risk differently from ucOC also remains uncertain. Our aim was to determine associations of serum ucOC with all-cause and cause-specific mortality and compare these with the corresponding associations of serum total osteocalcin (TOC), procollagen type I N-propeptide (PINP), and collagen type 1 C-terminal cross-linked telopeptide (CTX) in older men. We conducted a prospective cohort study of 3871 community-dwelling men, aged 77.0 ± 3.6 years at baseline, followed for a median of 12.3 years. Exposure variables were ucOC, TOC, PINP, and CTX concentrations assayed in serum. Outcomes were incidence of all deaths and deaths due to cardiovascular disease (CVD) or cancer, ascertained using death registry data. Cox regression analyses adjusted for cardiovascular risk factors and prevalent CVD and for prevalent cancer in analyses of cancer-related mortality. Higher concentrations of ucOC, PINP, and CTX were associated with all-cause mortality (hazard ratio [HR] per 1 standard deviation increase: ucOC 1.12, 95% confidence interval [CI] 1.06-1.18, p < 0.001; PINP HR = 1.06, 95% CI 1.01-1.11, p = 0.009; CTX HR = 1.13, 95% CI 1.08-1.19, p < 0.001), but TOC was not associated. Similar results were found after excluding men with an incident fracture during follow-up. Higher ucOC and CTX were associated with CVD mortality (ucOC HR per 1 SD increase 1.13, 95% CI 1.05-1.22, p = 0.001; CTX HR = 1.12, 95% CI 1.04-1.20, p = 0.003), but this result was not significant in competing risks analysis. Higher CTX was also associated with cancer mortality (HR = 1.12, 95% CI 1.01-1.23, p = 0.024). In conclusion, in older men, higher bone turnover, assessed by BTMs including ucOC, is a biomarker for all-cause mortality risk. Undercarboxylated osteocalcin was a more informative biomarker for this outcome than TOC. Higher CTX was associated with all-cause and cancer-related mortality. Further evaluation of causality and potential underlying mechanisms is warranted. © 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).

Predictors of Mortality and Refracture in Patients Older Than 65 Years With a Proximal Femur Fracture

OBJECTIVES

To evaluate potential predictors of subsequent fracture and increased mortality in a population 65 years or older who suffered a proximal femur fragility fracture.

METHODS

This was a longitudinal study that included patients with a proximal femur fragility fracture, referred from the Orthopedics Inpatient Department to the Rheumatology Department's Fracture Liaison Service, from March 2015 to March 2017.

RESULTS

Five hundred twenty-two patients were included, with a median age (IQR) of 84 years (interquartile range [IQR], 11 years), 79.7% (n = 416) female. Nine percent (n = 47) suffered a new fracture, with a median time to event of 298 days (IQR, 331 days). Cumulative probability without refracture at 12 months was 93% (95% confidence interval [CI], 90.2%-95.0%); 22.8% (n = 119) patients died, with median time to death of 126 days (IQR, 336 days). Cumulative survival probability at 12 months was 81.7 (95% CI, 77.9-84.8). Neurologic disease (hazard ratio [HR], 2.30; 95% CI, 0.97-5.50; p = 0.06) and chronic obstructive pulmonary disease (HR, 3.61; 95% CI, 1.20-10.9; p = 0.022) were both predictors of refracture. Age older than 80 years (HR, 1.54; 95% CI, 0.99-2.38; p = 0.052), higher degree of dependence (HR, 1.24;95% CI, 1.09-1.42; p = 0.001), male sex (HR, 1.55; 95% CI, 1.03-2.33; p = 0.034), femoral neck fracture (HR, 0.45; 95% CI, 0.24-0.88; p = 0.018), Charlson score (HR, 2.08; 95% CI, 1.17-3.69; p = 0.012), heart failure (HR, 2.44; 95% CI, 1.06-5.63; p = 0.037), hip bone mass density (HR, 3.99; 95% CI, 1.19-13.4; p = 0.025), hip T score (HR, 0.64; 95% CI, 0.44-0.93; p = 0.021), and β-crosslaps (HR, 1.98; 95% CI, 1.02-3.84; p = 0.042) all predicted a higher mortality.

CONCLUSIONS

Neurologic disease and chronic obstructive pulmonary disease may increase the risk of subsequent fracture after a hip fracture. Male sex, age, autonomy degree, femur bone mass density/T score, fracture type, Charlson score, diabetes mellitus, heart failure, and β-crosslaps had significant impact on survival. The authors highlight β-crosslaps as a potential serological marker of increased mortality in clinical practice.

Association between Circulating Osteocalcin and Cardiometabolic Risk Factors following a 4-Week Leafy Green Vitamin K-Rich Diet

<b><i>Background:</i></b> Evidence suggests that lower serum undercarboxylated osteocalcin (ucOC) may be negatively associated with cardiometabolic health. We investigated whether individuals with a suppression of ucOC following an increase in dietary vitamin K1 exhibit a relative worsening of cardiometabolic risk factors. <b><i>Materials and Methods:</i></b> Men (<i>n</i> = 20) and women (<i>n</i> = 10) aged 62 ± 10 years participated in a randomized, controlled, crossover study. The primary analysis involved using data obtained from participants following a high vitamin K1 diet (HK; 4-week intervention of increased leafy green vegetable intake). High and low responders were defined based on the median percent reduction (30%) in ucOC following the HK diet. Blood pressure (resting and 24 h), arterial stiffness, plasma glucose, lipid concentrations, and serum OC forms were assessed. <b><i>Results:</i></b> Following the HK diet, ucOC and ucOC/tOC were suppressed more (<i>p</i> &#x3c; 0.01) in high responders (41 and 29%) versus low responders (12 and 10%). The reduction in ucOC and ucOC/tOC was not associated with changes in blood pressure, arterial stiffness, plasma glucose, or lipid concentrations in the high responders (<i>p</i> &#x3e; 0.05). <b><i>Discussion/Conclusion:</i></b> Suppression of ucOC via consumption of leafy green vegetables has no negative effects on cardiometabolic health, perhaps, in part, because of cross-talk mechanisms.

The mediating role of the visceral fat area in the correlation between the serum osteocalcin levels and a prolonged QTc interval

AIMS

Osteocalcin, a bone-derived factor, could be a feasible marker for metabolic disorders and adverse cardiovascular outcomes. This study aimed to explore the correlation between serum osteocalcin levels and correct QT interval (QTc) interval prolongation, a risk factor of cardiac morbidity and mortality.

METHODS

We recruited 1210 subjects (age range: 26-80 years) in communities in Shanghai. Serum osteocalcin levels were determined using an electrochemiluminescence immunoassay. The QTc interval was measured using a 12-lead electrocardiogram and was calculated by the Bazett formula. A prolonged QTc interval was defined as QTc > 440 ms. Visceral fat area (VFA) was assessed by magnetic resonance imaging. A VFA of 80 cm² was applied as a cut-off point for central obesity.

RESULTS

Subjects with diabetes, overweight/obesity, or central obesity had significantly lower serum osteocalcin levels than those without (all P < 0.01). In subjects with a normal QTc interval, QTc interval lengthening accompanied decreasing osteocalcin levels (P_{for trend} = 0.033), and the decline was more obvious in subjects with a prolonged QTc interval (P_{for trend} = 0.022). Serum osteocalcin levels were correlated with the QTc interval (standardized β = -0.082, P = 0.005). Neither diabetes nor overweight/obesity was correlated with the QTc interval, whereas central obesity was positively correlated (P = 0.032). In addition, the correlation between osteocalcin levels and the QTc interval was attenuated when central obesity was included in the model simultaneously (standardized β = -0.075, P = 0.010). Mediation analysis revealed that VFA played a mediating role in the aforementioned correlation, and the estimated percentage of the total effect mediated by VFA was 20.9% (P = 0.007).

CONCLUSIONS

VFA partially mediated the inverse correlation between the serum osteocalcin levels and QTc interval, suggesting that improving fat metabolism may be a mechanism by which osteocalcin protects against cardiovascular diseases.

Serum Osteocalcin Level is Negatively Associated with Vascular Reactivity Index by Digital Thermal Monitoring in Kidney Transplant Recipients

BACKGROUND AND OBJECTIVES

Osteocalcin is the most abundant noncollagenous protein in bone matrix, which is considered a marker of bone formation. Previous studies indicate that circulating osteocalcin can be expressed by osteoblasts and even by osteoblast-like cells in vessel walls, and it is often associated with arterial stiffness. Our study aims to examine the potential association between osteocalcin levels and endothelial function among kidney transplant (KT) recipients.

MATERIALS AND METHODS

Fasting blood samples were obtained from 68 KT recipients. To measure the endothelial function and vascular reactivity index (VRI), a digital thermal monitoring test (VENDYS) was used. A commercial enzyme-linked immunosorbent assay kit was also utilized to measure serum total osteocalcin levels. In this study, a VRI of less than 1.0 indicated poor vascular reactivity; a VRI of 1.0-2.0 indicated intermediate vascular reactivity; and a VRI of 2.0 or higher indicated good vascular reactivity.

RESULTS

Our findings show that 8 KT recipients (11.8%) had poor vascular reactivity (VRI < 1.0), 26 (38.2%) had intermediate vascular reactivity (1.0 ≤ VRI < 2.0), and 34 (50%) had good vascular reactivity. Increased serum osteocalcin levels (p < 0.001) were found to be associated with poor vascular reactivity. Advanced age (r = -0.361, p = 0.002), serum alkaline phosphate level (r = -0.254, p = 0.037), and log-transformed osteocalcin levels (r = - 0.432, p < 0.001) were identified to be negatively correlated with VRI in KT recipients. Multivariable forward stepwise linear regression analysis revealed that the serum level of osteocalcin (β = -0.391, adjusted R² change = 0.174; p < 0.001) and advanced age (β = -0.308, adjusted R² change = 0.084; p = 0.005) were significantly and independently associated with VRI in KT recipients.

CONCLUSIONS

Higher serum osteocalcin level was associated with lower VRI and poorer endothelial dysfunction among KT recipients.

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.

Bone and Soft Tissue Turnover in Relation to All-cause Mortality in Postmenopausal Women

BACKGROUND

The relationship between levels of extracellular matrix (ECM) turnover and mortality is currently unknown. The study aimed to determine if levels of ECM turnover are predictors of all-cause mortality in a large cohort of postmenopausal women.

METHODS

5,855 postmenopausal Danish women enrolled in the Prospective Epidemiologic Risk Factor (PERF) study. Baseline demographics and serum were collected at registration. Dates of death were obtained from the Danish Death Registry. ECM turnover was evaluated by serological biomarkers measuring bone (telopeptide of type I collagen [CTX-1] and osteocalcin) and soft tissue (formation of type VI collagen [PRO-C6], MMP-degraded type IV collagen [C4M], formation of type III collagen [PRO-C3], and MMP-degraded type I collagen [C1M]) turnover. Multivariate Cox analyses were performed with 3, 5, and 15 years of follow-up.

RESULTS

The association of bone turnover (CTX-1 and osteocalcin) with all-cause mortality was U-shaped for all time periods. After adjustment for possible confounders, the lowest quintile of bone formation and degradation remained significant for all time periods. We observed J-shaped association between all-cause mortality and PRO-C6, C4M, and PRO-C3, and there was a linear association between C1M and all-cause mortality. After adjustment for possible confounders, the highest quintile of the soft tissue turnover biomarkers (PRO-C6, C4M, PRO-C3, and C1M) remained significantly associated with all-cause mortality for all time periods.

CONCLUSION

Both low and high levels of tissue turnover were associated with increased risk of all-cause mortality in postmenopausal women. Overall, these results highlight the importance of bone and soft tissue homeostasis.

Osteoporosis and the Critically Ill Patient

Improved survival after critical illness has led to recognition of impaired recovery following critical illness as a major public health problem. A consistent association between critical illness and accelerated bone loss has been described, including changes in bone turnover markers, bone mineral density, and fragility fracture rate. An association between accelerated bone turnover and increased mortality after critical illness is probable. Assessment of the effect of antifracture agents on fracture rate and mortality in the high-risk population of postmenopausal women with prolonged ventilation is warranted.

Osteocalcin and carotid-femoral pulse wave velocity in patients on peritoneal dialysis

Objective

Vascular calcification is a cardiovascular risk factor in dialysis patients. Vascular calcification involves a complex process of biomineralization resembling osteogenesis, which leads to arterial stiffness. Osteocalcin is the most abundant noncollagenous protein in the bone matrix. It is synthesized in the bone by osteoblasts and reflects the rate of bone formation. The aim of this study was to evaluate the relationship between serum osteocalcin levels and the carotid-femoral pulse wave velocity (cfPWV) in peritoneal dialysis (PD) patients.

Materials and Methods

Serum intact osteocalcin and cfPWV were measured in 62 PD patients. Those with CfPWV values >10 m/s were defined as the high central arterial stiffness group, while those with values ≤10 m/s were regarded as the low central arterial stiffness group, according to the European Society of Hypertension and of the European Society of Cardiology guidelines.

Results

Seventeen of the 62 PD patients (27.4%) were in the high central arterial stiffness group. The high central arterial stiffness group were older (P = 0.002), had a longer PD vintage (P = 0.018), and had higher serum osteocalcin levels (P = 0.001) than those in the low group. Multivariate logistic regression analysis showed that the osteocalcin level (odds ratio: 1.069, 95% confidence interval (CI): 1.005-1.137, P = 0.035), PD vintage (odds ratio: 1.028, 95% CI: 1.010-1.048, P = 0.003), and age (odds ratio: 1.081, 95% CI: 1.005-1.162, P = 0.035) were independently associated with central arterial stiffness in PD patients. Among these patients, cfPWV (β: 0.216, P = 0.001) values and log-transformed intact parathyroid hormone (β: -'0.447, P < 0.001) levels were independently associated with the osteocalcin level in PD patients after multivariate forward stepwise linear regression analysis.

Conclusion

Older PD patients with a longer PD vintage and higher serum osteocalcin levels had higher central arterial stiffness as measured by cfPWV. The serum osteocalcin level is an independent marker of central arterial stiffness in PD patients.

The Association Between Osteocalcin and Chronic Inflammation in Patients with Type 2 Diabetes Mellitus

Osteocalcin acts as an endocrine hormone to regulate energy homeostasis. Although several in vivo and in vitro studies suggest that osteocalcin is involved in chronic inflammation, the association between osteocalcin and chronic inflammation in humans is unknown. In this cross-sectional study, 246 patients with type 2 diabetes mellitus (T2DM) were recruited to investigate the association of bone turnover markers with chronic inflammation parameters such as high-sensitive C-reactive protein (hsCRP), ferritin, and leukocyte subtype counts. Bone-specific alkaline phosphatase (BAP), total osteocalcin (OC), undercarboxylated OC (ucOC), and urinary N-terminal cross-linked telopeptide of type-I collagen (uNTX) were measured. Multiple regression analysis adjusted for age, duration of diabetes, body mass index, estimated glomerular filtration rate, and hemoglobin A1c showed that serum OC levels were significantly and negatively associated with hsCRP, ferritin, basophil count, and monocyte count (β = - 0.18, p = 0.013; β = - 0.22, p = 0.031; β = - 0.14, p = 0.038; and β = - 0.17, p = 0.012, respectively). Moreover, serum ucOC levels were significantly and negatively associated with hsCRP, ferritin, total leukocyte count, neutrophil count, and monocyte count (β = - 0.24, p = 0.007; β =- 0.37, p = 0.003; β = - 0.21, p = 0.007; β = - 0.24, p = 0.002; and β = - 0.20, p = 0.011, respectively). The ratio of ucOC to OC was significantly and negatively associated with ferritin (β = - 0.31, p = 0.014). However, neither BAP nor uNTX was associated with any chronic inflammation parameters. This is the first study to show that serum OC and ucOC levels were negatively associated with chronic inflammation parameters such as hsCRP, ferritin, and leukocyte subtypes in patients with T2DM. Therefore, OC could be a therapeutic target for protecting against chronic inflammation.

Changes in bone mineral density in women before critical illness: a matched control nested cohort study

The contribution of premorbid bone health to accelerated bone loss following critical illness is unknown. This study compared bone density in women before critical illness to women who did not become critically ill. Overall bone density was similar, although femoral neck bone mass increased immediately prior to critical illness.

PURPOSE

The relative contribution of acute and chronic factors to accelerated loss of bone mineral density (BMD) following critical illness is unknown. This study compared the BMD trajectory of women before critical illness to the BMD trajectory of women who did not become critically ill.

METHODS

This prospective, nested, age- and medication-matched, case-control study compared trajectory of BMD in women in the Geelong Osteoporosis study (GOS) requiring admission to an Australian Intensive Care Unit (ICU) between June 1998 and March 2016, to women not admitted to ICU. The main outcome was age and medication use adjusted change in BMD.

RESULTS

A total of 52 women, with a mean age of 77 ± 9 years were admitted to ICU, predominantly post-surgery (75%), during the study period. A greater age-adjusted annual rate of decline was observed for pre-ICU women compared to no-ICU women for AP spine BMD (-0.010 ± 0.002 g/cm² vs -0.005 ± 0.002 g/cm², p = 0.01) over the 15-year study period. In participants with multiple BMDs 2 years before critical illness, a significantly greater increase in femoral neck BMD compared to age- and medication-matched controls was observed (difference in BMD, ICU vs no-ICU = 0.037 ± 0.013 g/cm², p = 0.006).

CONCLUSION

In a cohort of women with predominantly surgical ICU admission, bone health prior to critical illness was comparable to age- and medication-matched controls, with a relative increase in femoral neck bone mass immediately prior to critical illness. These findings suggest critical illness-related bone loss cannot be entirely explained as a continuation of pre-morbid bone trajectory.

Undercarboxylated Osteocalcin: Experimental and Human Evidence for a Role in Glucose Homeostasis and Muscle Regulation of Insulin Sensitivity

Recent advances have indicated that osteocalcin, and in particular its undercarboxylated form (ucOC), is not only a nutritional biomarker reflective of vitamin K status and an indicator of bone health but also an active hormone that mediates glucose metabolism in experimental studies. This work has been supported by the putative identification of G protein-coupled receptor, class C, group 6, member A (GPRC6A) as a cell surface receptor for ucOC. Of note, ucOC has been associated with diabetes and with cardiovascular risk in epidemiological studies, consistent with a pathophysiological role for ucOC in vivo. Limitations of existing knowledge include uncertainty regarding the underlying mechanisms by which ucOC interacts with GPRC6A to modulate metabolic and cardiovascular outcomes, technical issues with commonly used assays for ucOC in serum, and a paucity of clinical trials to prove causation and illuminate the scope for novel health interventions. A key emerging area of research is the role of ucOC in relation to expression of GPRC6A in muscle, and whether exercise interventions may modulate metabolic outcomes favorably in part via ucOC. Further research is warranted to clarify potential direct and indirect roles for ucOC in human health and cardiometabolic diseases.

Bone Turnover Status: Classification Model and Clinical Implications

Aim: To develop a practical model for classification bone turnover status and evaluate its clinical usefulness. Methods: Our classification of bone turnover status is based on internationally recommended biomarkers of both bone formation (N-terminal propeptide of type1 procollagen, P1NP) and bone resorption (beta C-terminal cross-linked telopeptide of type I collagen, bCTX), using the cutoffs proposed as therapeutic targets. The relationships between turnover subtypes and clinical characteristic were assessed in1223 hospitalised orthogeriatric patients (846 women, 377 men; mean age 78.1±9.50 years): 451(36.9%) subjects with hip fracture (HF), 396(32.4%) with other non-vertebral (non-HF) fractures (HF) and 376 (30.7%) patients without fractures. Resalts: Six subtypes of bone turnover status were identified: 1 - normal turnover (P1NP>32 μg/L, bCTX≤0.250 μg/L and P1NP/bCTX>100.0[(median value]); 2- low bone formation (P1NP ≤32 μg/L), normal bone resorption (bCTX≤0.250 μg/L) and P1NP/bCTX>100.0 (subtype2A) or P1NP/bCTX<100.0 (subtype 2B); 3- low bone formation, high bone resorption (bCTX>0.250 μg/L) and P1NP/bCTX<100.0; 4- high bone turnover (both markers elevated ) and P1NP/bCTX>100.0 (subtype 4A) or P1NP/bCTX<100.0 (subtype 4B). Compared to subtypes 1 and 2A, subtype 2B was strongly associated with nonvertebral fractures (odds ratio [OR] 2.0), especially HF (OR 3.2), age>75 years and hyperparathyroidism. Hypoalbuminaemia and not using osteoporotic therapy were two independent indicators common for subtypes 3, 4A and 4B; these three subtypes were associated with in-hospital mortality. Subtype 3 was associated with fractures (OR 1.7, for HF OR 2.4), age>75 years, chronic heart failure (CHF), anaemia, and history of malignancy, and predicted post-operative myocardial injury, high inflammatory response and length of hospital stay (LOS) above10 days. Subtype 4A was associated with chronic kidney disease (CKD), anaemia, history of malignancy and walking aids use and predicted LOS>20 days, but was not discriminative for fractures. Subtype 4B was associated with fractures (OR 2.1, for HF OR 2.5), age>75 years, CKD and indicated risks of myocardial injury, high inflammatory response and LOS>10 days. Conclusions: We proposed a classification model of bone turnover status and demonstrated that in orthogeriatric patients altered subtypes are closely related to presence of nonvertebral fractures, comorbidities and poorer in-hospital outcomes. However, further research is needed to establish optimal cut points of various biomarkers and improve the classification model.

Association of Bone Mineral Density, Bone Turnover Markers, and Vertebral Fractures with All-Cause Mortality in Type 2 Diabetes Mellitus

Patients with type 2 diabetes mellitus (T2DM) have an increased risk of fragility fracture. However, the association between diabetes-related osteoporosis and mortality in T2DM remains unknown. This historical cohort study assessed the endpoint of all-cause mortality in patients with T2DM. According to our hospital record, bone parameters were examined in 797 patients from 1997 to 2009. We excluded 78 because of diseases affecting bone metabolism and could not follow-up 308 patients. Finally, in 411 patients, the associations of bone turnover markers, bone mineral density (BMD), and the prevalence of vertebral fractures with mortality were investigated by Cox regression analyses adjusted for confounding factors. Of 411 patients, 56 died during the follow-up period of almost 7 years. Cox regression analyses showed that reduced BMD at the lumbar spine (LS) and femoral neck (FN) (T-score ≤ -2.5) and severe vertebral fractures were associated with higher mortality (hazard ratio [HR] 3.25, 95% confidence interval [CI] 1.48-7.16, p = 0.003 for LS-T score ≤ -2.5; HR 5.19, 95% CI 1.83-14.75, p = 0.002 for FN-T score ≤ -2.5; HR 2.93, 95% CI 1.42-6.02, p = 0.004 for multiple vertebral fractures; HR 7.64, 95% CI 2.13-27.42, p = 0.002 for grade 3 vertebral fracture). Separate analysis in men and women showed that decreased serum osteocalcin was associated with mortality in women (HR 3.82, 95% CI 1.01-14.46 per SD decrease, p = 0.048). The present study is the first to show the association of reduced BMD and severe vertebral fractures with increased all-cause mortality in patients with T2DM. Moreover, higher serum osteocalcin was significantly associated with decreased mortality in women with T2DM.

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.

Relationship between Bone Health Biomarkers and Cardiovascular Risk in a General Adult Population

Purpose/Introduction: Osteoporosis (OP) and cardiovascular (CV) disease emerge as closely related conditions, showing common risk factors and/or pathophysiological mechanisms. The aim of this study was to evaluate the association between bone health markers (BHM) and individual CV risk factors and overall CV risk (FRAMINGHAM-FRS, and PROCAM scores) in a general adult population.

METHODS

In 103 subjects (21 males; age: 56 ± 12 years), vitamin D (25(OH)D), osteocalcin (OC), bone alkaline phospatase (BALP), procollagen I aminoterminal propeptide (P1NP), CTx-telopeptide, as well clinical history and life style were evaluated.

RESULTS

Aging (p < 0.001) and glycemia (p < 0.05) emerged as independent 25(OH)D predictors. Aging (p < 0.001), male sex (p < 0.05), and obesity (p < 0.05) represented independent OC determinants. Aging (p < 0.05) was the only independent BALP determinant. After multivariate adjustment, low 25(OH)D (<20 ng/mL) (Odds ratio OR (95% confidence intervals CI)) (5 (1.4-18) p < 0.05) and elevated OC (>75th percentile-16.6 ng/mL) (6.7 (1.9-23.8) p < 0.01) were found to be significant FRS predictors, while subjects with elevated OC and/or BALP (>75th percentile-9.8 μg/L) showed a higher CV risk as estimated by PROCAM (3.6 (1.2-10.7) p < 0.05). CTx and P1NP did not significantly correlate with CV risk factors or scores.

CONCLUSION

As we go further into bone and CV physiology, it is evident that a close relationship exists between these diseases. Further studies are needed to investigate mechanisms by which bone turnover markers are related to metabolic risk and could modulate CV risk. This knowledge may help to develop possible multiple-purpose strategies for both CV disease and OP prevention and treatment.

Multifaceted interaction of bone, muscle, lifestyle interventions and metabolic and cardiovascular disease: role of osteocalcin

Undercarboxylated osteocalcin (ucOC) may play a role in glucose homeostasis and cardiometabolic health. This review examines the epidemiological and interventional evidence associating osteocalcin (OC) and ucOC with metabolic risk and cardiovascular disease. The complexity in assessing such correlations, due to the observational nature of human studies, is discussed. Several studies have reported that higher levels of ucOC and OC are correlated with lower fat mass and HbA1c. In addition, improved measures of glycaemic control via pharmacological and non-pharmacological (e.g. exercise or diet) interventions are often associated with increased circulating levels of OC and/or ucOC. There is also a relationship between lower circulating OC and ucOC and increased measures of vascular calcification and cardiovascular disease. However, not all studies have reported such relationship, some with contradictory findings. Equivocal findings may arise because of the observational nature of the studies and the inability to directly assess the relationship between OC and ucOC on glycaemic control and cardiovascular health in humans. Studying OC and ucOC in humans is further complicated due to numerous confounding factors such as sex differences, menopausal status, vitamin K status, physical activity level, body mass index, insulin sensitivity (normal/insulin resistance/T2DM), tissue-specific effects and renal function among others. Current observational and indirect interventional evidence appears to support a relationship between ucOC with metabolic and cardiovascular disease. There is also emerging evidence to suggest a direct role of ucOC in human metabolism. Further mechanistic studies are required to (a) clarify causality, (b) explore mechanisms involved and

Relationship between bone turnover and left ventricular function in primary hyperparathyroidism: The EPATH trial

Observational studies suggested a link between bone disease and left ventricular (LV) dysfunction that may be pronounced in hyperparathyroid conditions. We therefore aimed to test the hypothesis that circulating markers of bone turnover correlate with LV function in a cohort of patients with primary hyperparathyroidism (pHPT). Cross-sectional data of 155 subjects with pHPT were analyzed who participated in the "Eplerenone in Primary Hyperparathyroidism" (EPATH) Trial. Multivariate linear regression analyses with LV ejection fraction (LVEF, systolic function) or peak early transmitral filling velocity (e', diastolic function) as dependent variables and N-terminal propeptide of procollagen type 1 (P1NP), osteocalcin (OC), bone-specific alkaline phosphatase (BALP), or beta-crosslaps (CTX) as the respective independent variable were performed. Analyses were additionally adjusted for plasma parathyroid hormone, plasma calcium, age, sex, HbA1c, body mass index, mean 24-hours systolic blood pressure, smoking status, estimated glomerular filtration rate, antihypertensive treatment, osteoporosis treatment, 25-hydroxy vitamin D and N-terminal pro-brain B-type natriuretic peptide. Independent relationships were observed between P1NP and LVEF (adjusted β-coefficient = 0.201, P = 0.035) and e' (β = 0.188, P = 0.042), respectively. OC (β = 0.192, P = 0.039) and BALP (β = 0.198, P = 0.030) were each independently related with e'. CTX showed no correlations with LVEF or e'. In conclusion, high bone formation markers were independently and paradoxically related with better LV diastolic and, partly, better systolic function, in the setting of pHPT. Potentially cardio-protective properties of stimulated bone formation in the context of hyperparathyroidism should be explored in future studies.

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.

Advanced Age, High β-CTX Levels, and Impaired Renal Function are Independent Risk Factors for All-Cause One-Year Mortality in Hip Fracture Patients

Risk factors for increased mortality in hip fracture patients include older age, male sex, fracture type, bone mineral density, and pre-existing co-morbidities. The role of biochemical and other anthropometric parameters on hip fracture mortality remains unclear. The aim of this study was to identify the risk factors for one-year mortality in patients with hip fractures. A total of 236 consecutive patients (59 males) with hip fractures were followed over a one-year period. Patient age, gender, type of fracture, type of treatment, time from admission to surgery, type of anesthesia, body mass index, and electrocardiograms were recorded. Complete blood counts, serum electrolytes, urea, creatinine, d-dimers, calcium, phosphate, osteocalcin, and beta-isomerised C-terminal telopeptide of collagen type I (β-CTX) were measured at admission and estimated glomerular filtration rate (eGFR) was calculated. Multivariate Cox regression models were used to analyze the association of these parameters with survival. One-year mortality rate was 28.4%. Age was independently associated with mortality (HR 1.117, 95% CI 1.062-1.174, P < 0.001). In a multivariable model, mortality was increased in patients with higher β-CTX (HR 4.63 95% CI 1.87-11.45, P = 0.001) and lower eGFR (HR 0.972, 95% CI 0.956-0.987, P < 0.001). Patients younger than 84 years, with eGFR < 55.4 ml/min had ten times higher mortality rates (3.2 vs. 24.5%, HR 9.73, 95% CI 2.06-45.93) as well as those with β-CTX > 0.276 g/L (3.5 vs. 25.7%, HR 9.5, 95% CI 2.11-42.76). Advanced age, high β-CTX levels, and impaired renal function are independent risk factors of mortality in patients with hip fractures.

Lower bone turnover markers in metabolic syndrome and diabetes: the population-based Study of Health in Pomerania

BACKGROUND AND AIMS

Accumulating evidence demonstrates an important interaction between bone and energy metabolism. We aimed to study the associations of three bone turnover markers (BTM: osteocalcin, beta-crosslaps, procollagen type 1 N-terminal propeptide) as well as of 25-hydroxyvitamin D and parathyroid hormone with metabolic syndrome (MetS) or type 2 diabetes mellitus (T2DM) in a large population-based cohort.

METHODS AND RESULTS

This cross-sectional study comprised 2671 adult men and women participating in the first follow-up of the population-based Study of Health in Pomerania (SHIP-1). Multivariable logistic regression analyses were performed to assess sex-specific associations between the BTMs, 25-hydroxyvitamin D or parathyroid hormone and metabolic disease. All models were adjusted for age, body mass index, smoking status, physical activity, estimated glomerular filtration rate and month of blood sampling. The models for women were further adjusted for menopausal status. Higher BTM or 25-hydroxyvitamin D concentrations were associated with significantly lower odds for metabolic disease, while there was no association between parathyroid hormone and MetS or T2DM.

CONCLUSION

Our results contribute to the accumulating evidence of a cross-sectional association between high BTM or 25-hydroxyvitamin D concentrations and a lower prevalence of MetS or T2DM. Further research is necessary to evaluate the mechanisms underlying these results.

The association between critical illness and changes in bone turnover in adults: a systematic review

SUMMARY

Critical illness may lead to altered bone turnover and associated adverse health outcomes. This systematic review found moderate evidence for a positive association between critical illness and increased bone turnover. Prospective cohort studies that identify the extent and risk factors for critical illness related bone loss are required.

INTRODUCTION

Intensive care patients face health issues that extend beyond their critical illness and result in significant morbidity and mortality. Critical illness may result in altered bone turnover due to associated immobilisation, inflammation, exposure to medications that effect bone and calcium metabolism, and endocrine dysfunction. The aim of this study was to synthesise the existing evidence for altered bone turnover in adults admitted to intensive care.

METHODS

A literature search using MEDLINE and EMBASE was performed from 1965 to March 2013. Reviewed studies investigated the relationship between critical illness and evidence of altered bone turnover (bone turnover markers, bone mineral density, or fracture). Studies were rated upon their methodological quality, and a best-evidence synthesis was used to summarise the results.

RESULTS

Four cohort and seven case-control studies were identified for inclusion, of which five studies were rated as being of higher methodological quality. Ten of the studies measured bone turnover markers, and one study fracture rate. Findings were consistent across studies, and best-evidence analysis resulted in a conclusion that moderate evidence exists for an association between critical illness requiring admission to intensive care and altered bone turnover.

CONCLUSION

A positive association between critical illness requiring intensive care admission and bone turnover exists, although data are limited, and the risk factors and the nature of the relationship are not yet understood. Prospective cohort studies that identify risk factors and extent of critical illness related bone turnover changes are required.

Association of bone turnover markers with mortality in women referred to coronary angiography: the Ludwigshafen Risk and Cardiovascular Health (LURIC) study

We examined the association of fatal events with beta-crosslaps (β-CTX) and osteocalcin (OC) concentrations in women. We observed an independent association of β-CTX and OC concentrations with fatal events in women at high to intermediate cardiovascular risk.

INTRODUCTION

There is some evidence suggesting an association of β-CTX and OC with fatal events in men and frail elderly subjects. We aimed to examine the association of fatal events with β-CTX and OC in women.

METHODS

We measured β-CTX and OC in 986 women aged 65 (58-72) years referred to coronary angiography.

RESULTS

Compared to the first β-CTX quartile, the crude hazard ratios (HRs) for all-cause and cardiovascular mortality in the highest β-CTX quartile were 2.50 (1.65-3.81) and 3.28 (1.82-5.91), respectively. In multivariate adjusted models, HRs for all-cause and cardiovascular mortality in the highest β-CTX quartile were 1.72 (1.09-2.70) and 2.31 (1.24-4.32), respectively. The lowest 25-hydroxyvitamin D [25(OH)D] quartile was significantly associated with increased risk of all-cause and cardiovascular mortality in multivariate adjusted models. In those models, the highest β-CTX quartile was associated with an increased risk of all-cause and cardiovascular mortality. For OC concentrations, we found a reverse J-shaped association with noncardiovascular mortality. Using the first quartile as reference, crude and multivariate adjusted HRs for noncardiovascular mortality in the second and third OC quartile were 0.41 (0.19-0.90) [multivariate: 0.40 (0.18-0.88)] and 0.51 (0.25-1.06) [multivariate: 0.43 (0.20-0.94)], respectively. The lowest 25(OH)D quartile was associated with a trend towards increased risk of noncardiovascular mortality in multivariate analysis. In that analysis, OC quartile 2 and 3 were significantly associated with lower risk of noncardiovascular mortality.

CONCLUSIONS

We observed an independent association of high β-CTX with all-cause and cardiovascular mortality and a reverse J-shaped association of OC with noncardiovascular mortality.