Influence of bone remodelling rate on quantitative ultrasound parameters at the calcaneus and DXA BMDa of the hip and spine in middle-aged and elderly European men: the European Male Ageing Study (EMAS)

Bone turnover markers in the preoperative assessment of bone quality - A prospective investigation of bone microstructure and advanced glycation endproducts in lumbar fusion patients

INTRODUCTION

Effective tools to evaluate bone quality preoperatively are scarce and the standard method to determine bone quality requires an invasive biopsy. A non-invasive, and preoperatively available method for bone quality assessment would be of clinical value. The purpose of this study is to investigate the associations of bone formation marker, serum bone alkaline phosphatase (BAP), and bone resorption marker, urine collagen cross-linked N-telopeptide (uNTX) to volumetric bone mineral density (vBMD), fluorescent advanced glycation endproducts (fAGEs) and bone microstructure.

MATERIALS AND METHODS

A cross-secional analysis using prospective data of patients undergoing lumbar spinal fusion was performed. BAP and uNTX were preoperatively collected. Quantitative computed tomography (QCT) was performed at the lumbar spine (vBMD ≤ 120 mg/cm3 osteopenic/osteoporotic). Bone biopsies from the posterior superior iliac spine were obtained and evaluated with multiphoton fluorescence microscopy for fAGEs and microcomputed tomography (µCT) for bone microarchitecture. Correlations between BAP/uNTX to vBMD, fAGEs and µCT parameters were assessed with Spearman's ρ. Receiver operating characteristic (ROC) analysis evaluated BAP and uNTX as predictors for osteopenia/osteoporosis. Multivariable linear regression models adjusting for age, sex, BMI, race and diabetes mellitus determined associations between BAP/uNTX and fAGEs.

RESULTS

127 prospectively enrolled patients (50.4% female, 62.5 years, BMI 28.7 kg/m2) were analyzed. uNTX (ρ=-0.331,p < 0.005) and BAP (ρ=-0.245,p < 0.025) decreased with cortical fAGEs, and uNTX (ρ=-0.380,p < 0.001) decreased with trabecular fAGEs. BAP and uNTX revealed no significant correlation with vBMD. ROC analysis for BAP and uNTX discriminated osteopenia/osteoporosis with AUC of 0.477 and 0.561, respectively. In the multivariable analysis, uNTX decreased with increasing trabecular fAGEs after adjusting for covariates (β = 0.923;p = 0.031).

CONCLUSION

This study demonstrated an inverse association of bone turnover markers and fAGEs. Both uNTX and BAP could not predict osteopenia/osteoporosis in the spine. uNTX reflects collagen characteristics and might have a complementary role to vBMD, as a non-invasive tool for bone quality assessment in spine surgery.

Rapid bone microarchitecture decline in older men with high bone turnover-the prospective STRAMBO study

Older men with high bone turnover have faster bone loss. We assessed the link between the baseline levels of bone turnover markers (BTMs) and the prospectively assessed bone microarchitecture decline in men. In 825 men aged 60-87 yr, we measured the serum osteocalcin (OC), bone alkaline phosphatase (BAP), N-terminal propeptide of type I procollagen (PINP), and C-terminal telopeptide of type I collagen (CTX-I), and urinary total deoxypyridinoline (tDPD). Bone microarchitecture and strength (distal radius and distal tibia) were estimated by high-resolution pQCT (XtremeCT, Scanco Medical) at baseline and then after 4 and 8 yr. Thirty-seven men took medications affecting bone metabolism. Statistical models were adjusted for age and BMI. At the distal radius, the decrease in the total bone mineral density (Tt.BMD), cortical BMD (Ct.BMD), cortical thickness (Ct.Thd), and cortical area (Ct.Ar) and failure load was faster in the highest vs the lowest CTX-I quartile (failure load: -0.94 vs -0.31% yr-1, P < .001). Patterns were similar for distal tibia. At the distal tibia, bone decline (Tt.BMD, Ct.Thd, Ct.Ar, Ct.BMD, and failure load) was faster in the highest vs the lowest tDPD quartile. At each skeletal site, the rate of decrease in Tb.BMD differed between the extreme OC quartiles (P < .001). Men in the highest BAP quartile had a faster loss of Tt.BMD, Tb.BMD, reaction force, and failure load vs the lowest quartile. The link between PINP and bone decline was poor. The BTM score is the sum of the nos. of the quartiles for each BTM. Men in the highest quartile of the score had a faster loss of cortical bone and bone strength vs the lowest quartile. Thus, in the older men followed prospectively for 8 yr, the rate of decline in bone microarchitecture and estimated bone strength was 50%-215% greater in men with high bone turnover (highest quartile, CTX-I above the median) compared to the men with low bone turnover (lowest quartile, CTX-I below the median).

Mineral and bone disorder after kidney transplantation: a single-center cohort study

BACKGROUND

The assessment and prevention of mineral and bone disorder (MBD) in kidney transplant recipients (KTRs) have not been standardized. This study aimed to evaluate MBD one year after kidney transplantation (KT) and identify the influencing factors of MBD.

METHODS

A total of 95 KTRs in our center were enrolled. The changes in bone mineral density (BMD) and bone metabolism biochemical markers, including serum calcium (Ca), phosphorus(P), 25-hydroxyvitamin D(25(OH)vitD), intact parathyroid hormone (iPTH), bone alkaline phosphatase, osteocalcin (OC), type I collagen N-terminal peptide and type I collagen C-terminal peptide (CTx), over one year after KT were assessed. The possible influencing factors of BMD were analyzed. The relationships between bone metabolism biochemical markers were evaluated. The indicators between groups with or without iPTH normalization were also compared.

RESULTS

MBD after KT was manifested as an increased prevalence of hypophosphatemia and bone loss, persistent 25(OH)vitD deficiency, and partially decreased PTH and bone turnover markers (BTMs). Femoral neck BMD was positively correlated with body mass index (BMI) and postoperative 25(OH)vitD, and negatively correlated with postoperative PTH. Lumbar spine BMD was positively correlated with BMI and preoperative TG, and negatively correlated with preoperative OC and CTx. BMD loss was positively associated with glucocorticoid accumulation. Preoperative and postoperative iPTH was negatively correlated with postoperative serum P and 25(OH)vitD, and positively correlated with postoperative Ca and BTMs. The recipients without iPTH normalization, who accounted for 41.0% of all KTRs, presented with higher Ca, lower P, higher BTMs, advanced age, and a higher prevalence of preoperative parathyroid hyperplasia.

CONCLUSIONS

MBD persisted after KT, showing a close relationship with hyperparathyroidism, high bone turnover, and glucocorticoid accumulation.

Associations of bone mineral density with sex hormone-binding globulin (SHBG) and testosterone in middle-aged Saudi men: a cross-sectional study

Objective

The present cross-sectional study examined the association between circulating levels of sex hormone-binding globulin (SHBG) and testosterone with bone mineral density (BMD) in middle-aged Arab men.

Methods

Clinical data of 103 middle-aged Saudi men (mean age 60.7±7.2) were extracted from the Osteoporosis Registry of the Chair for Biomarkers of Chronic Diseases, King Saud University in Riyadh, Saudi Arabia. Participants were categorized according to the presence of osteopenia (T-score -1.0 to -2.5) (N=47) and controls (N=56). Data collected included demographics and anthropometrics as well as levels of sex hormone-binding globulin (SHBG), testosterone and follicle-stimulating hormone (FSH) which were measured using commercially available assays. Free androgen index (FAI) was calculated.

Results

Those with osteopenia had significantly lower levels of FAI (p<0.05), and higher levels of SHBG (p<0.004) and FSH (p<0.005). In the osteopenia group, SHBG was positively correlated with age (r=0.33, p<0.05), while it was inversely correlated with BMD spine (r = -0.39, p<0.05) and T-score femur (r= -0.35, p<0.05) in the same group. Furthermore, testosterone was inversely correlated with BMI in the osteopenia group (r= -0.33, p<0.05) while FAI was positively correlated with T-score femur (r = 0.36, p<0.05) as well as in all participants (r= 0.24, p<0.05). Among controls, FAI had an inverse correlation with FSH (r= -0.28, p<0.05) and over-all (r= -0.22, p<0.05).

Conclusion

In summary, the associations elicited suggest that circulating levels of SHBG and FAI may be against age-related bone loss in middle-aged men.

Natural history of mineral metabolism, bone turnover and bone mineral density in de novo renal transplant recipients treated with a steroid minimization immunosuppressive protocol

The skeletal effects of renal transplantation are not completely understood, especially in patients managed with a steroid minimization immunosuppressive protocol and long term. We enrolled 69 adult transplant recipients (39 males; ages 51.1 ± 12.2 years), free of antiresorptive therapy and managed with a steroid minimization immunosuppressive protocol, into a 5-year prospective observational study to evaluate changes in areal bone mineral density (aBMD), mineral metabolism and bone remodelling. Dual energy X-ray absorptiometry, laboratory parameters of mineral metabolism (including parathyroid hormone, sclerostin and fibroblast growth factor 23) and non-renal cleared bone turnover markers (BTMs) (bone-specific alkaline phosphatase, trimeric N-terminal propeptide and tartrate-resistant acid phosphatase 5b) were assessed at baseline and 1 and 5 years post-transplantation. The mean cumulative methylprednisolone exposure at 1 and 5 years amounted to 2.5 ± 0.8 and 5.8 ± 3.3 g, respectively. Overall, bone remodelling activity decreased after transplantation. Post-transplant aBMD changes were minimal and were significant only in the ultradistal radius during the first post-operative year {median -2.2% [interquartile range (IQR) -5.9-1.2] decline, P = 0.01} and in the lumbar spine between Years 1 and 5 [median 1.6% (IQR -3.2-7.0) increase, P = 0.009]. BTMs, as opposed to mineral metabolism parameters and cumulative corticosteroid exposure, associated with aBMD changes, both in the early and late post-transplant period. Most notably, aBMD changes inversely associated with bone remodelling changes. In summary, in de novo renal transplant recipients treated with a steroid minimization immunosuppressive protocol, BMD changes are limited, highly variable and related to remodelling activity rather than corticosteroid exposure.

Relationship Between Sex Steroids and Deterioration of Bone Microarchitecture in Older Men: The Prospective STRAMBO Study

In older men, low estrogen levels are associated with poor bone microarchitecture. Data on androgens are discordant. We studied the link between baseline sex steroid levels (total 17β -estradiol [17βE2], total testosterone [tT], calculated bioavailable 17βE2 [bio-17βE2], and apparent free testosterone concentration [AFTC]) and bone microarchitecture deterioration assessed prospectively in a 820 older men followed for 8 years. Bone microarchitecture was assessed by HR-pQCT at baseline, then after 4 and 8 years. At both the skeletal sites, the bone microarchitecture deterioration rate did not correlate with serum levels of tT and 17βE2. At the distal radius, cortical area (Ct.Ar) decreased more rapidly in the lowest versus the highest AFTC quartile. At the distal tibia, cortical thickness (Ct.Th) decreased and trabecular area (Tb.Ar) increased more rapidly in the highest versus the lowest AFTC quartile. At the tibia, bone mineral content (BMC), total volumetric bone mineral density (Tt.vBMD), Ct.Th, and Ct.Ar decreased, whereas Tb.Ar increased faster in the lowest versus the highest bio-17βE2 quartile. In men who had both AFTC and bio-17βE2 in the lowest quartile (high-risk group), distal radius cortical vBMD (Ct.vBMD) decreased more rapidly compared with men who had both hormones in the three upper quartiles (reference group). At the distal tibia, Tt.vBMD, Ct.Th, Ct.Ar, and Ct.vBMD decreased, whereas Tb.Ar increased more rapidly in the high-risk group versus the reference group. In men receiving androgen deprivation therapy (ADT) for prostate cancer, BMC, Tt.vBMD, Ct.Th, Ct.Ar, and Ct.vBMD decreased, whereas Tb.Ar increased more rapidly than in men not receiving ADT at both the skeletal sites. Thus, in older men followed up prospectively, low levels of bio-17βE2, and to a smaller extent AFTC, are associated with accelerated cortical bone deterioration. Cortical bone deterioration was strongly accelerated in men receiving ADT who had very low levels of all sex steroids. © 2019 American Society for Bone and Mineral Research.

The ability of calcaneal and multisite quantitative ultrasound variables in the identification of osteoporosis in women and men

Objectives

The aim of this study was to assess the ability of calcaneal and multisite quantitative ultrasound (QUS) parameters in the identification of osteoporosis in women and men.

Patients and methods

A total of 131 women (mean age 53.7±11.9 years; range, 21 to 79 years) and 109 men (mean age 57.8±13.7 years; range, 24 to 85 years) whose bone mineral density (BMD) at the spine and proximal femur was measured between January 2010 and January 2012, using dual-energy X-ray absorptiometry (DXA) were included. Acoustic bone properties were also examined using both a calcaneal and a multisite QUS. The receiver operating characteristic analysis with the calculation of areas under the curve (AUCs) to evaluate the ability of both QUS devices for the identification of osteoporosis. We also calculated a lower and an upper threshold at a specificity of 90% and at a sensitivity of 90%, respectively, for the identification of osteoporosis along with a threshold/cut-off value with the best compromise between sensitivity and specificity.

Results

All calcaneal QUS parameters showed significant AUCs within the range of 0.712 (for Broadband Ultrasound Attenuation [BUA]) and 0.764 (for Speed of Sound [SOS]) in women and ranging from 0.661 (for BUA) to 0.735 (for SOS) in men, while only radial SOS of the multisite QUS demonstrated a significant AUC value of 0.661 for identifying osteoporosis in women. A Quantitative Ultrasound Index T-score of -1.53 for women and -1.68 for men showed sensitivity and specificities around 70%.

Conclusion

Based on the results of this study, all calcaneal QUS parameters in both women and men and possibly radial SOS measurements of the multisite QUS in women may be helpful for the identification of osteoporosis.

Body composition and circulating estradiol are the main bone density predictors in healthy young and middle-aged men

PURPOSE

Current fracture risk assessment options in men call for improved evaluation strategies. Recent research directed towards non-classic bone mass determinants have often yielded scarce and conflicting results. We aimed at investigating the impact of novel potential bone mass regulators together with classic determinants of bone status in healthy young and middle-aged men.

METHODS

Anthropometric measurements, all-site bone mineral density (BMD) and body composition parameters assessed by dual-energy X-ray absorptiometry and also serum concentrations of (1) the adipokines leptin and resistin, (2) vitamin D and parathormone (PTH), (3) sex hormone binding globulin (SHBG), total testosterone and estradiol (free testosterone was also calculated) and (4) C-terminal telopeptide of type I collagen (CTx) were obtained from 30 apparently healthy male volunteers aged 20-65 years enrolled in this cross-sectional study.

RESULTS

Only lean mass (LM) and total estradiol independently predicted BMD in men in multiple regression analysis, together explaining 49% (p ≤ 0.001) of whole-body BMD variance. Hierarchical regression analysis with whole-body BMD as outcome variable demonstrated that the body mass index (BMI) beta coefficient became nonsignificant when LM was added to the model. Adipokines, fat parameters, testosterone (total and free), SHBG, PTH and vitamin D were not independently associated with BMD or CTx.

CONCLUSIONS

The present study shows that LM and sex hormones-namely estradiol-are the main determinants of bone mass in young and middle-aged men. The effects of BMI upon BMD seem to be largely mediated by LM. Lifestyle interventions should focus on preserving LM in men for improved bone outcomes.

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.

The association of testosterone, sex hormone-binding globulin, and insulin-like growth factor-1 with bone parameters in Korean men aged 50 years or older

Testosterone and insulin-like growth factor-1 (IGF-1) are essential factors for the maintenance of bone health in men. However, the results for the association of testosterone and IGF-1 with bone parameters were not consistent in prior studies. We evaluated the relationship of testosterone, sex hormone-binding globulin (SHBG), and IGF-1 with bone mineral density (BMD) and bone turnover markers (BTMs) in Korean men. We enrolled 1227 men aged ≥50 years in this cross-sectional study. Serum levels of total testosterone (TT), SHBG, IGF-1, osteocalcin, and C-terminal cross-linking telopeptide of type I collagen (CTX) were measured. Free testosterone (FT) was calculated using Vermeulen's method. BMD was measured by dual-energy X-ray absorptiometry. TT level was not related to BMD or BTMs in the unadjusted model; however, after adjusting for SHBG and IGF-1, the association between TT and BTMs was significant (β = -0.139 for osteocalcin and β = -0.204 for CTX). SHBG levels were negatively associated with lumbar BMD, and positively associated with BTMs in all models. As SHBG level increased, the prevalence of osteopenia or osteoporosis defined by BMD significantly increased (OR of 1SD change, 1.24). IGF-1 levels were significantly related with BMD, but not with BTMs. Meanwhile, FT levels were positively associated with BMD and negatively associated with BTMs. In conclusion, SHBG levels were independently related with bone parameters and osteopenia in men aged ≥50 years. IGF-1 levels were positively associated with BMD, but not with BTMs. SHBG may play a role in regulating age-related bone loss in men after middle-age.

Bone turnover predicts change in volumetric bone density and bone geometry at the radius in men

Peripheral quantitative computed tomography scans of the distal and midshaft radius were performed in 514 European men aged 40-79 years at baseline and a median of 4.3 years later. Age-related changes in volumetric bone mineral density (vBMD) and bone geometry were greater in men with higher biochemical markers of bone turnover at baseline.

INTRODUCTION

This study aimed to determine prospective change in bone density and geometry at the radius in men and examine the influence of bone turnover markers and sex hormones on that change.

METHODS

Men aged 40-79 years were recruited from population registers in Manchester (UK) and Leuven (Belgium). At baseline, markers of bone formation (P1NP and osteocalcin) and resorption (β-cTX and ICTP) were assessed. Total and bioavailable testosterone and oestradiol were also measured. Peripheral quantitative computed tomography (pQCT) was used to scan the radius at distal and midshaft sites at the baseline assessment and a median of 4.3 years later.

RESULTS

Five hundred fourteen men, mean (SD) age of 59.6 (10.5) years, contributed to the data. At the midshaft site, there was a significant decrease in mean cortical vBMD (-0.04 %/year), bone mineral content (BMC) (-0.1 %/year) and cortical thickness (-0.4 %/year), while total and medullary area increased (+0.5 and +2.4 %/year respectively). At the distal radius, total vBMD declined (-0.5 %/year) and radial area increased (+0.6 %/year). Greater plasma concentrations of bone resorption and formation markers were associated with greater decline in BMC and cortical area at the midshaft and total vBMD at the distal site. Increased bone resorption was linked with an increase in total and medullary area and decrease in cortical thickness at the midshaft. Sex hormone levels were unrelated to change in pQCT parameters.

CONCLUSIONS

Age-related changes in vBMD and bone geometry are greater in men with higher biochemical markers of bone turnover at baseline. Sex hormones have little influence on change in pQCT parameters.

Estrogens and Androgens in Skeletal Physiology and Pathophysiology

Estrogens and androgens influence the growth and maintenance of the mammalian skeleton and are responsible for its sexual dimorphism. Estrogen deficiency at menopause or loss of both estrogens and androgens in elderly men contribute to the development of osteoporosis, one of the most common and impactful metabolic diseases of old age. In the last 20 years, basic and clinical research advances, genetic insights from humans and rodents, and newer imaging technologies have changed considerably the landscape of our understanding of bone biology as well as the relationship between sex steroids and the physiology and pathophysiology of bone metabolism. Together with the appreciation of the side effects of estrogen-related therapies on breast cancer and cardiovascular diseases, these advances have also drastically altered the treatment of osteoporosis. In this article, we provide a comprehensive review of the molecular and cellular mechanisms of action of estrogens and androgens on bone, their influences on skeletal homeostasis during growth and adulthood, the pathogenetic mechanisms of the adverse effects of their deficiency on the female and male skeleton, as well as the role of natural and synthetic estrogenic or androgenic compounds in the pharmacotherapy of osteoporosis. We highlight latest advances on the crosstalk between hormonal and mechanical signals, the relevance of the antioxidant properties of estrogens and androgens, the difference of their cellular targets in different bone envelopes, the role of estrogen deficiency in male osteoporosis, and the contribution of estrogen or androgen deficiency to the monomorphic effects of aging on skeletal involution.

Lower bone turnover and relative bone deficits in men with metabolic syndrome: a matter of insulin sensitivity? The European Male Ageing Study

We examined cross-sectional associations of metabolic syndrome and its components with male bone turnover, density and structure. Greater bone mass in men with metabolic syndrome was related to their greater body mass, whereas hyperglycaemia, hypertriglyceridaemia or impaired insulin sensitivity were associated with lower bone turnover and relative bone mass deficits.

INTRODUCTION

Metabolic syndrome (MetS) has been associated with lower bone turnover and relative bone mass or strength deficits (i.e. not proportionate to body mass index, BMI), but the relative contributions of MetS components related to insulin sensitivity or obesity to male bone health remain unclear.

METHODS

We determined cross-sectional associations of MetS, its components and insulin sensitivity (by homeostatic model assessment-insulin sensitivity (HOMA-S)) using linear regression models adjusted for age, centre, smoking, alcohol, and BMI. Bone turnover markers and heel broadband ultrasound attenuation (BUA) were measured in 3129 men aged 40-79. Two centres measured total hip, femoral neck, and lumbar spine areal bone mineral density (_aBMD, n = 527) and performed radius peripheral quantitative computed tomography (pQCT, n = 595).

RESULTS

MetS was present in 975 men (31.2 %). Men with MetS had lower β C-terminal cross-linked telopeptide (β-CTX), N-terminal propeptide of type I procollagen (PINP) and osteocalcin (P < 0.0001) and higher total hip, femoral neck, and lumbar spine _aBMD (P ≤ 0.03). Among MetS components, only hypertriglyceridaemia and hyperglycaemia were independently associated with PINP and β-CTX. Hyperglycaemia was negatively associated with BUA, hypertriglyceridaemia with hip _aBMD and radius cross-sectional area (CSA) and stress-strain index. HOMA-S was similarly associated with PINP and β-CTX, BUA, and radius CSA in BMI-adjusted models.

CONCLUSIONS

Men with MetS have higher _aBMD in association with their greater body mass, while their lower bone turnover and relative deficits in heel BUA and radius CSA are mainly related to correlates of insulin sensitivity. Our findings support the hypothesis that underlying metabolic complications may be involved in the bone's failure to adapt to increasing bodily loads in men with MetS.

Are bone turnover markers associated with volumetric bone density, size, and strength in older men and women? The AGES-Reykjavik study

Association between serum bone formation and resorption markers and bone mineral, structural, and strength variables derived from quantitative computed tomography (QCT) in a population-based cohort of 1745 older adults was assessed. The association was weak for lumbar spine and femoral neck areal and volumetric bone mineral density.

INTRODUCTION

The aim of this study was to examine the relationship between levels of bone turnover markers (BTMs; osteocalcin (OC), C-terminal cross-linking telopeptide of type I collagen (CTX), and procollagen type 1N propeptide (P1NP)) and quantitative computed tomography (QCT)-derived bone density, geometry, and strength indices in the lumbar spine and femoral neck (FN).

METHODS

A total of 1745 older individuals (773 men and 972 women, aged 66-92 years) from the Age, Gene/Environment Susceptibility (AGES)-Reykjavik cohort were studied. QCT was performed in the lumbar spine and hip to estimate volumetric trabecular, cortical, and integral bone mineral density (BMD), areal BMD, bone geometry, and bone strength indices. Association between BTMs and QCT variables were explored using multivariable linear regression.

RESULTS

Major findings showed that all BMD measures, FN cortical index, and compressive strength had a low negative correlation with the BTM levels in both men and women. Correlations between BTMs and bone size parameters were minimal or not significant. No associations were found between BTMs and vertebral cross-sectional area in women. BTMs alone accounted for only a relatively small percentage of the bone parameter variance (1-10 %).

CONCLUSION

Serum CTX, OC, and P1NP were weakly correlated with lumbar spine and FN areal and volumetric BMD and strength measures. Most of the bone size indices were not associated with BTMs; thus, the selected bone remodeling markers do not reflect periosteal bone formation. These results confirmed the limited ability of the most sensitive established BTMs to predict bone structural integrity in older adults.

Relationship Between Urinary Cross-Linked N-Telopeptide of Type-I Collagen and Heel Stiffness Index Measured by Quantitative Ultrasound in Middle-Aged and Elderly Men

The aim of the present study was to investigate the age-related patterns and the relationship between levels of urinary cross-linked N-telopeptide of type-I collagen (NTx) and heel stiffness index measured by quantitative ultrasound (QUS) in men with a special reference to age groups of aged 40 to 59 years and ≥60 years.A total of 379 men participated in this study. Heel stiffness index (bone mass) was measured by QUS. Spot urine samples were collected, and urinary NTx was measured. The values were corrected for creatinine (Cre) concentration.Stiffness index was significantly lower in men aged ≥60 years compared with men aged 40 to 59 years (P < 0.0001). There was no significant difference of Log (NTx/Cre) by 10-year age groups. Multiple regression analysis showed that higher level of urinary NTx/Cre was significantly correlated with lower stiffness index after adjusting for age and body mass index in men aged ≥60 years, but not in men aged 40 to 59 years.Higher rates of bone resorption were associated with lower stiffness index only in elderly men. Our results may indicate a different mechanism of low bone mass among different age groups.

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.

Sex steroid actions in male bone

Sex steroids are chief regulators of gender differences in the skeleton, and male gender is one of the strongest protective factors against osteoporotic fractures. This advantage in bone strength relies mainly on greater cortical bone expansion during pubertal peak bone mass acquisition and superior skeletal maintenance during aging. During both these phases, estrogens acting via estrogen receptor-α in osteoblast lineage cells are crucial for male cortical and trabecular bone, as evident from conditional genetic mouse models, epidemiological studies, rare genetic conditions, genome-wide meta-analyses, and recent interventional trials. Genetic mouse models have also demonstrated a direct role for androgens independent of aromatization on trabecular bone via the androgen receptor in osteoblasts and osteocytes, although the target cell for their key effects on periosteal bone formation remains elusive. Low serum estradiol predicts incident fractures, but the highest risk occurs in men with additionally low T and high SHBG. Still, the possible clinical utility of serum sex steroids for fracture prediction is unknown. It is likely that sex steroid actions on male bone metabolism rely also on extraskeletal mechanisms and cross talk with other signaling pathways. We propose that estrogens influence fracture risk in aging men via direct effects on bone, whereas androgens exert an additional antifracture effect mainly via extraskeletal parameters such as muscle mass and propensity to fall. Given the demographic trends of increased longevity and consequent rise of osteoporosis, an increased understanding of how sex steroids influence male bone health remains a high research priority.

Androgens and estrogens in skeletal sexual dimorphism

Bone is an endocrine tissue expressing androgen and estrogen receptors as well as steroid metabolizing enzymes. The bioactivity of circulating sex steroids is modulated by sex hormone-binding globulin and local conversion in bone tissue, for example, from testosterone (T) to estradiol (E2) by aromatase, or to dihydrotestosterone by 5α-reductase enzymes. Our understanding of the structural basis for gender differences in bone strength has advanced considerably over recent years due to increasing use of (high resolution) peripheral computed tomography. These microarchitectural insights form the basis to understand sex steroid influences on male peak bone mass and turnover in cortical vs trabecular bone. Recent studies using Cre/LoxP technology have further refined our mechanistic insights from global knockout mice into the direct contributions of sex steroids and their respective nuclear receptors in osteoblasts, osteoclasts, osteocytes, and other cells to male osteoporosis. At the same time, these studies have reinforced the notion that androgen and estrogen deficiency have both direct and pleiotropic effects via interaction with, for example, insulin-like growth factor 1, inflammation, oxidative stress, central nervous system control of bone metabolism, adaptation to mechanical loading, etc., This review will summarize recent advances on these issues in the field of sex steroid actions in male bone homeostasis.

Low Testosterone Levels Are Associated With Poor Peripheral Bone Mineral Density and Quantitative Bone Ultrasound at Phalanges and Calcaneus in Healthy Elderly Men

Variations in sex hormones influence bone health in men. Aging in men is associated with a decrease in testosterone (T) levels. We examined the relationship between T levels and changes in bone health status as measured by quantitative ultrasound (QUS) at the phalanges and the os calcis and by peripheral bone mineral density (pBMD) at the phalanges in healthy elderly Spanish men. We examined 162 men aged 65–88 years and assessed total serum T concentrations. Total serum T < 300 ng/dL was used as the threshold for biochemical T deficiency. The sample was divided into low ( n = 66) or normal ( n = 96) T levels; both groups were matched for age, weight, height, and body mass index ( p > .05 for all the comparisons). All measured bone parameters were higher in the normal serum T group ( p < .05). Multiple regression analysis revealed that serum T was an independent predictor of both QUS at the calcaneus and phalangeal pBMD. Our data indicate that T is an independent determinant of QUS at the os calcis and pBMD at the phalanges in elderly Spanish men.

Male hypogonadism and skeletal health

PURPOSE OF REVIEW

To examine the role of testosterone in skeletal health in men.

RECENT FINDINGS

Evidence from recent studies shows that the contributing role of testosterone to osteoporosis is modest and likely trumped by other factors such as estradiol levels. A few studies have documented an association between low testosterone levels and lower bone mineral density (BMD), increased prevalence of osteoporosis of the hip and low bone mass-related fractures. Other studies, however, have found that testosterone levels are not independent predictors of bone resorption or formation markers, BMD at the hip or incident fractures. Curiously, hypogonadism does not account for the increased osteoporosis seen in men with Klinefelter Syndrome. Regardless of hypogonadism status, two recent clinical trials have found fewer new morphometric vertebral fractures in men treated with zoledronic acid and increased BMD in men treated with denosumab. Denosumab was also shown to modestly increase bone-metastasis-free survival in men with castration-resistant prostate cancer.

SUMMARY

Although male hypogonadism is associated with osteoporosis, estradiol is likely to be the more important hormone for bone health. Although a few large randomized controlled trials have been conducted in men with low bone density (a subset of whom have hypogonadism), more trials are needed, particularly with fractures as the main outcome.

Osteoporosis in older men: recent advances in pathophysiology and treatment

Osteoporosis remains underrecognized and undertreated but more so in men, adding considerably to fracture burden and costs. Fracture-related morbidity and mortality is higher in men, partly due to greater frailty. Improved peak bone mass, geometry and turn-over contribute to lower fracture incidence in men. Bioavailable androgens and oestrogens regulate these aspects of musculoskeletal sexual dimorphism, yet the direct cellular and molecular targets of sex steroids in bone remain incompletely understood. Screening with clinical risk factors and dual energy X-ray absorptiometry are advised in men from age 70 (or 50 with additional risk factors). We now have compelling evidence that osteoporosis drugs are equally effective in men and women, not only to increase bone density but also to prevent osteoporotic fractures. The use of testosterone or selective androgen receptor modulators for osteoporosis, sarcopenia, frailty and falls in men with late-onset hypogonadism requires further investigation.

Active vitamin D (1,25-dihydroxyvitamin D) and bone health in middle-aged and elderly men: the European Male Aging Study (EMAS)

CONTEXT

There is little information on the potential impact of serum 1,25-dihydroxyvitamin D [1,25(OH)2D] on bone health including turnover.

OBJECTIVE

The objective of the study was to determine the influence of 1,25(OH)2D and 25-hydroxyvitamin D [25(OH)D] on bone health in middle-aged and older European men.

DESIGN, SETTING, AND PARTICIPANTS

Men aged 40-79 years were recruited from population registers in 8 European centers. Subjects completed questionnaires that included questions concerning lifestyle and were invited to attend for quantitative ultrasound (QUS) of the heel, assessment of height and weight, and a fasting blood sample from which 1,25(OH)2D, 25(OH)D, and PTH were measured. 1,25(OH)2D was measured using liquid chromatography tandem mass spectrometry. Bone markers serum N-terminal propeptide of type 1 procollagen (P1NP) and crosslinks (β-cTX) were also measured. Dual-energy x-ray absorptiometry (DXA) of the hip and lumbar spine was performed in 2 centers.

MAIN OUTCOME MEASURE(S)

QUS of the heel, bone markers P1NP and β-cTX, and DXA of the hip and lumbar spine were measured.

RESULTS

A total of 2783 men, mean age 60.0 years (SD 11.0) were included in the analysis. After adjustment for age and center, 1,25(OH)2D was positively associated with 25(OH)D but not with PTH. 25(OH)D was negatively associated with PTH. After adjustment for age, center, height, weight, lifestyle factors, and season, 1,25(OH)2D was associated negatively with QUS and DXA parameters and associated positively with β-cTX. 1,25(OH)2D was not correlated with P1NP. 25(OH)D was positively associated with the QUS and DXA parameters but not related to either bone turnover marker. Subjects with both high 1,25(OH)2D (upper tertile) and low 25(OH)D (lower tertile) had the lowest QUS and DXA parameters and the highest β-cTX levels.

CONCLUSIONS

Serum 1,25(OH)2D is associated with higher bone turnover and poorer bone health despite being positively related to 25(OH)D. A combination of high 1,25(OH)2D and low 25(OH)D is associated with the poorest bone health.

Osteocalcin is associated with testosterone in the general population and selected patients with bone disorders

Research in the last decade has revealed that bone is not only a target tissue for numerous circulating hormones but functions as an endocrine organ itself. As a recent study demonstrated a stimulatory effect of the osteoblast-derived hormone osteocalcin (OCN) on testosterone production in mice, we investigated whether such an association can be replicated in humans. We used data from 1338 men (25-86 years) in the population-based epidemiological Study of Health in Pomerania and from 110 male outpatients with bone disorders (18-85 years) for the study. We analysed cross-sectional associations between OCN and total testosterone serum concentrations (TT), as well as associations between further markers of bone turnover [bone-specific alkaline phosphatase (BAP), serum C-terminal telopeptides of Type I collagen (CTX), urinary deoxypyridinoline] and TT using ordinary least square (OLS) regression models. Multivariable OLS models revealed a positive association between OCN and TT in the population-based (β coefficients for a one standard deviation increase, 0.590; standard error (SE), 0.175; p-value, <0.01) and patient-based (β coefficient, 0.575; SE, 0.132; p-value, <0.01) samples even after adjustment for age and body mass index (both samples), and time of blood sampling (population-based sample only). Furthermore, we observed positive associations between BAP and TT (β coefficient, 0.403; SE, 0.170; p-value, 0.02) as well as between CTX and TT (β coefficient, 0.733; SE, 0.172; p-value, <0.01) in men from the general population. The present investigation shows that OCN is associated with TT in the general population and in patients with bone disorders, and may thus indicate general male health status. Additional longitudinal observational studies are warranted to confirm our findings and future experimental research is necessary to elucidate potential mechanisms underlying the observed associations.