Procollagen type 1 amino-terminal propeptide (P1NP) and risk of hip fractures in elderly Norwegian men and women. A NOREPOS study

Association between bone turnover markers and FRAX predicted fracture risk in Chinese adults: a cross-sectional study

OBJECTIVE

Our study investigated the associations between bone turnover markers (BTMs) and bone mineral density (BMD) and fracture risk over the next 10 years. The objective of the study was to evaluate the potential effects of BTMs in fracture risk.

METHODS

Our cross-sectional study enrolled 580 participants (380 postmenopausal women and 200 men over the age of 50). All participants completed a questionnaire and dual-energy X-ray absorptiometry examination. We obtained BMD values for the lumbar spine, femoral neck, and total hip joint and biochemical indicators such as creatinine, type 1 procollagen N-terminal propeptide (P1NP), and beta cross-linked C-telopeptide of type 1 collagen (β-CTX). Furthermore, we used an online fracture risk assessment tool (FRAX) to calculate the probability of major osteoporotic fractures (PMOF) and hip fractures (PHF) over the next 10 years. We divided the participants into three groups based on the BMD T-score criteria: normal bone mass group (T-score ≥ - 1.0 SD), osteopenic group (- 2.5 SD < T-score < - 1.0 SD), and osteoporotic group (T-score ≤ - 2.5 SD). We compared differences in BTMs, BMD, and fracture risks among the three groups. Additionally, we evaluated differences in indicators between males and females and explored risk factors associated with BMD and fracture risk.

RESULTS

Postmenopausal women showed higher bone turnover markers, osteoporosis prevalence, and fracture risks compared to men. In a multivariate stepwise regression analysis, we identified P1NP was positively correlated with fracture risk for both PMOF (β = 0.087, p = 0.005) and PHF (β = 0.135, p < 0.001) over the next 10 years. In the logistic regression analysis, after adjusting for sex, we found that for every standard deviation increase in P1NP, the future 10-year risk of fractures increased by approximately 5.2-fold in the high PMOF group and 5.6-fold in the high PHF group.

CONCLUSION

Our study demonstrated that elevated serum P1NP levels were associated with increased fracture risk over a 10-year period. These findings suggested that serum P1NP measurement could be a valuable complementary tool alongside BMD measurements and FRAX assessments for identifying individuals at high risk of fracture.

Bone-derived factors mediate crosstalk between skeletal and extra-skeletal organs

Bone has long been acknowledged as a fundamental structural entity that provides support and protection to the body's organs. However, emerging research indicates that bone plays a crucial role in the regulation of systemic metabolism. This is achieved through the secretion of a variety of hormones, cytokines, metal ions, extracellular vesicles, and other proteins/peptides, collectively referred to as bone-derived factors (BDFs). BDFs act as a medium through which bones can exert targeted regulatory functions upon various organs, thereby underscoring the profound and concrete implications of bone in human physiology. Nevertheless, there remains a pressing need for further investigations to elucidate the underlying mechanisms that inform the effects of bone on other body systems. This review aims to summarize the current findings related to the roles of these significant modulators across different organs and metabolic contexts by regulating critical genes and signaling pathways in vivo. It also addresses their involvement in the pathogenesis of various diseases affecting the musculoskeletal system, circulatory system, glucose and lipid metabolism, central nervous system, urinary system, and reproductive system. The insights gained from this review may contribute to the development of innovative therapeutic strategies through a focused approach to bone secretomes. Continued research into BDFs is expected to enhance our understanding of bone as a multifunctional organ with diverse regulatory roles in human health.

Changes in bone turnover markers 6-12 months after bariatric surgery

A rise in bone turnover markers (BTM) after bariatric surgery predicts poor bone health years later. This study explored factors associated with BTM and changes in BTM after bariatric surgery. Inclusion criteria were subjects 18 to 65 years of age with morbid obesity undergoing bariatric surgery. All data were measured before and 6 and 12 months after surgery. The study included 104 subjects: women/men: 83/21; mean age 43.1 (SD 8.4) years; BMI: 38.8 kg/m2 (SD 3.8). Surgery with Roux-en-Y gastric bypass (RYGB) and sleeve gastrectomy (SG) was performed in 84 (81%) and 20 (19%) subjects, respectively. From before to 6-12 months after surgery, procollagen type 1 N-terminal propeptid (P1NP) increased by 45.6 µg/L (95% CI 41.5-50.0, p < 0.001), and alkaline phosphatase (ALP) by 10 U/L (95% CI 7-14, p < 0.001). The increases were significantly larger after RYGB than after SG. The APOE- Ɛ3 allele was associated with low levels of BTM and high levels of leptin. There was an unfavourable increase in BTM after bariatric surgery. SG compared to RYGB and the presence of the APOE-Ɛ3 allele were associated with less unfavourable effects. The study emphasises the importance of optimal prophylactic interventions after bariatric surgery to prevent osteoporosis.

Effectiveness and Usefulness of Bone Turnover Marker in Osteoporosis Patients: A Multicenter Study in Korea

BACKGROUND

This study aimed to investigate real-world data of C-terminal telopeptide (CTX), propeptide of type I collagen (P1NP), and osteocalcin through present multicenter clinical study, and retrospectively analyze the usefulness of bone turnover markers (BTMs) in Koreans.

METHODS

The study focused on pre- and post-menopausal patients diagnosed with osteoporosis and excluded patients without certain test results or with test intervals of over 1 year. The demographic data and 3 BTMs (CTX, P1NP, and osteocalcin) were collected. The patients were classified by demographic characteristics and the BTM concentrations were analyzed by the group.

RESULTS

Among women with no history of fractures, the levels of P1NP (N=2,100) were 43.544±36.902, CTX (N=1,855) were 0.373 ±0.927, and osteocalcin (N=219) were 10.81 ±20.631. Among men with no history of fractures, the levels of P1NP (N=221) were 48.498±52.892, CTX (N=201) were 0.370±0.351, and osteocalcin (N=15) were 7.868 ±10.674. Treatment with teriparatide increased the P1NP levels after 3 months in both men and women, with a 50% increase observed in women. Similarly, treatment with denosumab decreased the CTX levels after 3 months in both men and women, with a reduction of 50% observed in women.

CONCLUSIONS

The results of this study can contribute to the accurate assessment of bone replacement status in Koreans. We also provide the P1NP level in the Korean population for future comparative studies with other populations.

Foxf2 represses bone formation via Wnt2b/β-catenin signaling

Differentiation of mesenchymal stem cells (MSCs) into osteoblasts is a critical process for proper skeletal development and acquisition/maintenance of bone mass. However, since this regulatory mechanism has not yet been fully elucidated, the treatment of severe osteoporosis and fractures is a challenge. Here, through a comprehensive analysis of gene expression during the differentiation of MSCs into osteoblasts, we show that the forkhead transcription factor Foxf2 is a crucial regulator of this process. Foxf2 expression transiently increased during MSC osteoblastic differentiation. Overexpression of Foxf2 in MSCs inhibited osteoblastic differentiation, and conversely, knockdown of Foxf2 expression promoted this process. Osteoprogenitor-specific Foxf2 knockout mice developed a high bone mass phenotype due to increased bone formation. RNA-seq analysis and molecular experiments revealed that Foxf2 regulation of bone formation is mediated by Wnt2b. Knockdown of Foxf2 in mouse femurs enhanced bone regeneration in vivo. FOXF2 expression was correlated with hip bone mineral density in postmenopausal women with low bone mass. Finally, inhibition of FOXF2 promoted osteoblastic differentiation of human MSCs. This study uncovers a critical role of Foxf2 in the differentiation of MSCs into osteoblasts and provides insight into the pathogenesis associated with bone-related diseases such as osteoporosis and nonunion after fracture.

Dimethandrolone Undecanoate, a Novel, Nonaromatizable Androgen, Increases P1NP in Healthy Men Over 28 Days

CONTEXT

Dimethandrolone undecanoate (DMAU) is being developed as a male contraceptive. Daily oral administration of DMAU, a potent androgen that is not aromatized, markedly suppresses serum testosterone (T) and estradiol (E2) in healthy men. E2 deficiency can increase bone resorption in men.

OBJECTIVE

This work aimed to assess changes in bone turnover markers with DMAU administration in a 28-day study.

DESIGN

A randomized, double-blind, placebo-controlled study was conducted.

SETTING

This study took place at 2 academic medical centers.

PARTICIPANTS

Healthy men, age 18 to50 years (n = 81), participated.

INTERVENTION

Men received 0, 100, 200, or 400 mg of oral DMAU for 28 days. Serum C-terminal telopeptide of type I collagen (CTX; bone resorption marker) and procollagen type I amino-terminal propeptide (P1NP; bone formation marker) were measured on days 1 and 28.

MAIN OUTCOME MEASURES

Changes in bone turnover markers and serum hormones over the treatment period were measured.

RESULTS

On day 28, median serum T and E2 were markedly suppressed in all treatment groups vs placebo (P < .001 for both). Percentage change (%) in serum P1NP significantly differed across treatment groups (P = .007): Serum P1NP significantly increased in the 200 mg (5%, interquartile range [IQR] -7% to 27%) and 400 mg (22%, IQR -1% to 40%) groups relative to placebo (-8%, IQR -20% to 0%). Change (%) in serum CTX did not differ between groups (P = .09).

CONCLUSIONS

DMAU administration for 28 days to healthy men leads to marked suppression of serum T and E2, yet increases P1NP, a serum marker of bone formation. Longer-term studies of the potent androgen DMAU are warranted to determine its impact on bone health in men.

Association between bone mineral density and ulnar styloid fracture in older Japanese adults with low-energy distal radius fracture

We investigated the association of the ulnar styloid fracture (USF) with the bone mineral status and fractured radial displacement in elderly patients. The presence of USF correlates with decreased BMD and severe displacement of the radius. These findings are helpful in treating osteoporosis to prevent subsequent fragility fracture.

PURPOSE

The pathogenesis of ulnar styloid fracture (USF), which often occurs with distal radius fracture (DRF), is unclear. This study aimed to investigate whether USF concomitant with low-energy DRF was associated with the bone mineral status and the degree of radiographically observed pretreatment radius displacement in Japanese adults above 50 years of age.

METHODS

The study subjects were 45 (44 female, 1 male) consecutive patients aged > 50 years with DRF caused by falls from June 2015 to May 2016. Fractures due to high-energy injuries were excluded. Patients were divided into two groups according to the presence or absence of USF. Radius displacement was assessed on anteroposterior and lateral radiographs by measuring ulnar variance, radial inclination, and volar tilt at initial examination before manual reduction of the bone. Bone mineral density (BMD) of the lumbar spine, femoral neck, and distal radius was also measured by dual-energy X-ray absorptiometry within 1 week of injury.

RESULTS

Significant differences in the BMD values of femoral neck, ulnar variance, radial inclination, and volar tilt were found between patients with USF and those without USF (all comparisons, p < 0.05). Logistic regression analysis of all subject data identified that volar tilt was significantly associated with the presence of USF (p = 0.048).

CONCLUSIONS

The presence of USF in low-energy DRF correlates with the decreased BMD of femoral neck and severe displacement of radius in elderly patients. These findings are helpful for the treatment of osteoporosis to prevent subsequent fragility fracture.

Effects of a 3-month weight-bearing and resistance exercise training on circulating osteogenic cells and bone formation markers in postmenopausal women with low bone mass

Osteoporosis is a health issue in postmenopausal women. Physical activity is recommended in these subjects, since it has positive effects on bone mass. Cellular mechanisms underlying this effect are still unclear. Osteogenic cells, released after physical exertion, could be a key factor in exercise-induced bone formation.

INTRODUCTION

The aim of our research was to explore if a weight-bearing and resistance exercise program could positively affect circulating osteogenic cells (OCs), markers of bone formation and quality of life (QoL) in osteopenic postmenopausal women.

METHODS

We recruited 33 postmenopausal women with a T-score at lumbar spine or femoral neck between - 1 and - 2.5 SD. Anthropometric and fitness parameters, bone-remodeling markers, OCs, and QoL were evaluated at the time of enrolment, after 1-month run-in period, and after 3 months of weight-bearing and resistance exercise.

RESULTS

After 3 months of training, the pro-collagen type 1 N-terminal peptide (P1NP) and the number of OCs were significantly increased, with no significant increase of the type 1 collagen cross-linked C-telopeptide (sCTX). We also observed a significant increase in body height, one-repetition maximum (1RM) on the pull-down lat machine and leg press, and mean VO₂max. The increase of immature circulating OCs was significantly correlated with the improvement of 1RM both of the upper and lower limbs. Moreover, QoL was significantly improved with regard to pain, physical function, mental function, and general QoL. The improvement in QoL, namely in the overall score and in the pain score, was significantly correlated with the increase in height.

CONCLUSIONS

The exercise program we trialed is able to increase the markers of bone formation and the commitment of immature OCs with no significant increase in the markers of bone resorption. Our results confirm that combined weight-bearing and resistance physical activity is an effective tool to improve QoL of postmenopausal women with low bone mass.

TRIAL REGISTRATION

NCT03195517.

Age-related Reference Intervals for Total Collagen-I-N-terminal Propeptide in Healthy Korean Population

Background

Procollagen type I N-terminal propeptide (PINP) is one of the most clinically useful bone formation biomarkers. Therefore, the purpose of this study was to independently evaluate the performance of automated total PINP assay and established age- and gender-specific reference intervals for PINP in healthy Korean population.

Methods

The imprecision, linearity, and detection capability of Elecsys total PINP assay was determined and reference interval was established using 599 serums from Korean population with normal bone mineral densities based on bone densitometry. Age groups were divided into 20s, 30s, 40s, 50s, 60s and over.

Results

Elecsys total PINP had excellent performance in imprecision, linearity, and detection capability. When partitioning age groups in Korean male and female populations, there was significant difference in total PINP between different age groups. In male populations, PINP level was decreased with increasing age, then it remained steady after middle-age. In female populations, there was a decreasing tendency similar to that in the male population with a sharp increase in the 50 to 59 age group.

Conclusions

Elecsys total PINP assay showed precise and reliable performance in our study. We established age-related PINP reference intervals for Korean male and female population with normal bone mineral densities.

Bone Turnover Markers Are Not Associated With Hip Fracture Risk: A Case-Control Study in the Women's Health Initiative

Current guidelines recommend that serum C-terminal telopeptide of type I collagen (CTX) and serum procollagen type 1 aminoterminal propeptide (PINP), measured by standardized assays, be used as reference markers in observational and interventional studies. However, there are limited data to determine whether serum CTX and PINP are associated with hip fracture risk among postmenopausal women. We determined the associations of serum CTX and serum PINP with hip fracture risk among postmenopausal women aged 50 to 79 years at baseline. We performed a prospective case-control study (400 cases, 400 controls) nested in the Women's Health Initiative Observational Study, which enrolled participants at 40 US clinical centers. Cases were women with incident hip fracture not taking osteoporosis medication; hip fractures were confirmed using medical records. Untreated controls were matched by age, race/ethnicity, and date of blood sampling. Serum CTX and serum PINP were analyzed on 12-hour fasting blood samples. The main outcome measure was incident hip fracture risk (mean follow-up 7.13 years). After adjustment for body mass index, smoking, frequency of falls, history of fracture, calcium and vitamin D intake, and other relevant covariates, neither serum CTX level nor serum PINP level was statistically significantly associated with hip fracture risk (CTX p_trend  = 0.22, PINP p_trend  = 0.53). Our results do not support the utility of serum CTX level or PINP level to predict hip fracture risk in women in this age group. These results will inform future guidelines regarding the potential utility of these markers in fracture prediction. © 2018 American Society for Bone and Mineral Research.

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.

Lower serum P1NP/βCTX ratio and hypoalbuminemia are independently associated with osteoporotic nonvertebral fractures in older adults

Purpose

To estimate the discriminative value of serum P1NP/βCTX ratio and albumin levels in hospitalized orthogeriatric patients with and without nonvertebral fractures.

Methods

In 1,239 orthogeriatric patients (mean age 78.1±9.52 years, 69.1% women) including 854 (68.9%) with osteoporotic nonvertebral fractures (455 [36.7%] with hip fracture [HF]) and 385 (31.1%) without fractures, markers of bone formation (procollagen type 1 N-terminal propeptide [P1NP], osteocalcin [OC], and bone resorption (beta-C-terminal cross-linking telopeptide of type 1 collagen [βCTX]), indices of mineral metabolism, and parameters of liver and renal functions were assessed; data on clinical and laboratory characteristics were collected prospectively.

Results

Both lower serum P1NP/βCTX ratio and albumin concentration (as continuous or categorical variables) were independently associated with fracture presence in multivariate logistic regressions. Compared with the highest P1NP/βCTX tertile, the prevalence of HF, after adjustment for multiple covariates, was 3-fold higher in the lowest tertile and 1.5 times higher in the middle tertile; presence of any fracture was 2.3- and 1.6-fold higher, respectively; patients with albumin levels in the lowest tertile had multivariate odds ratio (OR) of 4.6 for HF and 2.8 for any fracture, in the middle tertile the ORs were 2.2 and 1.3, respectively. The P1NP/βCTX <100.0 (median) and hypoalbuminemia (<33 g/L) demonstrated area under the curve values for HF of 0.802 and 0.806, respectively, and for any fractures of 0.711 and 0.706, respectively. When both characteristics were combined, the ORs for HF or any fracture, compared with the nonfractured group, were 7.8 and 3.2, respectively, with an accuracy of 79.6% and 71.6%, respectively.

Conclusions

In orthogeriatric patients, both serum P1NP/βCTX ratio and albumin levels demonstrated an inverse dose–effect relationship with the prevalence of nonvertebral fractures and independently indicated fracture presence with acceptable discriminatory power. Lower P1NP/βCTX (<100) and hypoalbuminemia could be useful simple additive prognostic tools for fracture risk stratification in the elderly.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Cohort profile: Norwegian Epidemiologic Osteoporosis Studies (NOREPOS)

AIMS

This paper describes the history, purpose, data collection and contributions in the research collaboration Norwegian Osteoporosis Epidemiologic Studies (NOREPOS).

METHODS

NOREPOS encompasses almost 85,000 bone mineral density measurements within Cohort of Norway and data on almost 140,000 hip fractures in Norway 1994-2008. Included are anthropometric measurements, blood pressure, lipids and glucose, and 50 standard questions on sociodemographic factors, diseases and risk factors. Blood samples/DNA are stored. The main research question posed in NOREPOS is why hip fracture rates in Norway are the highest in the world. Data on hip fractures 2009-2013 will be added in 2014.

RESULTS

Main findings include: Every hour a Norwegian suffers a hip fracture; hip fracture incidence rates declined after 1999; only 16% of patients used anti-osteoporosis drugs 1 year after hip fracture; 25% of patients died within 1 year after the fracture; 12% suffered a new hip fracture within 10 years; rural dwellers had lower hip and forearm fracture incidence than city dwellers; magnesium in tap water may be protective whereas bacterial contamination, cadmium and lead may be harmful to bone health; low serum vitamin D and E levels were associated with higher hip fracture risk; vitamin A was not associated with fracture risk; and abdominal obesity increased the risk of hip fracture when BMI was accounted for.

CONCLUSIONS

NOREPOS encompasses a unique source of information for aetiological research, genetic studies as well as for biomarkers of osteoporosis and fractures. Because of the increasing number of elderly people in Europe, hip fractures will continue to pose an international public health and health care challenge.