Sex steroids and bone turnover markers in men with symptomatic vertebral fractures

Understanding the characteristics of idiopathic osteoporosis by a systematic review and meta-analysis

PURPOSE

To understand the pathophysiology of idiopathic osteoporosis (IOP) better, we conducted a systematic review and meta-analysis of bone mineral density (BMD), hormones, and bone turnover markers (BTMs) between IOP patients and healthy controls.

METHODS

Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, an appropriate search query was created, and three databases, including PubMed, ScienceDirect, and Google Scholar, were searched for screening relevant original articles. Feasible information, both qualitative and quantitative, was extracted and used to conduct meta-analyses. Publication bias and heterogeneity among studies were evaluated using appropriate statistical tools.

RESULTS

A total of 21 studies were included in the meta-analysis. There was reduced BMD at the lumbar spine (LS) (pooled: SDM: -2.38, p-value: 0.0001), femoral neck (FN) (pooled: SDM: -1.75 p-value: 0.0001), total hip (TH) (pooled: SDM: -1.825, p-value: 0.0001) and distal radius (DR) (pooled: SDM of -0.476, p-value: 0.0001), of which LS was the most affected site. There was no significant change in BTMs compared with healthy controls. Total estradiol (SDM: -1.357, p-value: 0.003) was reduced, and parathyroid hormone (PTH) (SDM: 1.51, p-value: 0.03) and sex hormone-binding globulin (SHBG) (SDM: 1.454, p-value: 0.0001) were elevated in IOP patients compared with healthy controls.

CONCLUSION

Our meta-analysis, the first of its kind on IOP, defines it as showing BMD decline maximally at LS compared with healthy controls without any alterations in the BTMs. Further studies are required to understand gender differences and the significance of altered hormonal profiles in this condition.

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.

Endocrine sequelae of hematopoietic stem cell transplantation: Effects on mineral homeostasis and bone metabolism

Hematopoietic stem cell transplantation (HSCT) is an established therapeutic strategy for the treatment of malignant (leukemia and lymphoma) and non-malignant (thalassemia, anemia, and immunodeficiency) hematopoietic diseases. Thanks to the improvement in patient care and the development of more tolerable conditioning treatments, which has extended the applicability of therapy to the elderly, a growing number of patients have successfully benefited from HSCT therapy and, more importantly, HSCT transplant-related mortality has consistently reduced in recent years. However, concomitantly to long term patient survival, a growing incidence of late HSCT-related sequelae has been reported, being variably associated with negative effects on quality of life of patients and having a non-negligible impact on healthcare systems. The most predominantly observed HSCT-caused complications are chronic alterations of the endocrine system and metabolism, which endanger post-operative quality of life and increase morbidity and mortality of transplanted patients. Here, we specifically review the current knowledge on HSCT-derived side-effects on the perturbation of mineral metabolism; in particular, the homeostasis of calcium, focusing on current reports regarding osteoporosis and recurrent renal dysfunctions that have been observed in a percentage of HSC-transplanted patients. Possible secondary implications of conditioning treatments for HSCT on the physiology of the parathyroid glands and calcium homeostasis, alone or in association with HSCT-caused renal and bone defects, are critically discussed as well.

Bone health in ageing men

Osteoporosis does not only affect postmenopausal women, but also ageing men. The burden of disease is projected to increase with higher life expectancy both in females and males. Importantly, osteoporotic men remain more often undiagnosed and untreated compared to women. Sex steroid deficiency is associated with bone loss and increased fracture risk, and circulating sex steroid levels have been shown to be associated both with bone mineral density and fracture risk in elderly men. However, in contrast to postmenopausal osteoporosis, the contribution of relatively small decrease of circulating sex steroid concentrations in the ageing male to the development of osteoporosis and related fractures, is probably only minor. In this review we provide several clinical and preclinical arguments in favor of a 'bone threshold' for occurrence of hypogonadal osteoporosis, corresponding to a grade of sex steroid deficiency that in general will not occur in many elderly men. Testosterone replacement therapy has been shown to increase bone mineral density in men, however data in osteoporotic ageing males are scarce, and evidence on fracture risk reduction is lacking. We conclude that testosterone replacement therapy should not be used as a sole bone-specific treatment in osteoporotic elderly men.

Role of sex hormone-binding globulin in the free hormone hypothesis and the relevance of free testosterone in androgen physiology

According to the free hormone hypothesis, biological activity of a certain hormone is best reflected by free rather than total hormone concentrations. A crucial element in this theory is the presence of binding proteins, which function as gatekeepers for steroid action. For testosterone, tissue exposure is governed by a delicate equilibrium between free and total testosterone which is determined through interaction with the binding proteins sex hormone-binding globulin and albumin. Ageing, genetics and various pathological conditions influence this equilibrium, hereby possibly modulating hormonal exposure to the target tissues. Despite ongoing controversy on the subject, strong evidence from recent in vitro, in vivo and human experiments emphasizes the relevance of free testosterone. Currently, however, clinical possibilities for free hormone diagnostics are limited. Direct immunoassays are inaccurate, while gold standard liquid chromatography with tandem mass spectrometry (LC-MS/MS) coupled equilibrium dialysis is not available for clinical routine. Calculation models for free testosterone, despite intrinsic limitations, provide a suitable alternative, of which the Vermeulen calculator is currently the preferred method. Calculated free testosterone is indeed associated with bone health, frailty and other clinical endpoints. Moreover, the added value of free testosterone in the clinical diagnosis of male hypogonadism is clearly evident. In suspected hypogonadal men in whom borderline low total testosterone and/or altered sex hormone-binding globulin levels are detected, the determination of free testosterone avoids under- and overdiagnosis, facilitating adequate prescription of hormonal replacement therapy. As such, free testosterone should be integrated as a standard biochemical parameter, on top of total testosterone, in the diagnostic workflow of male hypogonadism.

Bone turnover markers as determinants of bone density and fracture in men with distal forearm fractures: the pathogenesis examined in the Mr F study

The pathogenesis for low-trauma wrist fractures in men is not fully understood. This study found that these men had evidence of significantly higher bone turnover compared with control subjects. Bone turnover markers were negative predictors of bone mineral density and were a predictor of fracture.

INTRODUCTION

Men with distal forearm fractures have reduced bone density, an increased risk of osteoporosis and of further fractures. The aim of this study was to investigate whether or not men with distal forearm fractures had evidence of altered bone turnover activity.

METHODS

Fifty eight men with low-trauma distal forearm fracture and 58 age-matched healthy control subjects were recruited. All subjects underwent a DXA scan of the forearm, both hips, and lumbar spine, biochemical investigations, and health questionnaires. Measurements of beta crosslaps (βCTX), procollagen type I N-terminal propeptide (PINP), sclerostin, Dickkopf-1 (Dkk1), and fibroblast growth factor 23 (FGF 23) were made.

RESULTS

Men with fracture had significantly higher PINP than controls at 39.2 ng/ml (SD 19.5) versus 33.4 ng/ml (SD13.1) (p<0.001). They also had significantly higher βCTX at 0.45 ng/ml (SD 0.21) versus 0.37 ng/ml (SD 0.17) (p= 0.037). Fracture subjects had significantly lower aBMD and PINP was a negative predictor of aBMD at the total hip and βCTX a negative predictor of forearm aBMD. Sclerostin was a positive predictor of aBMD at the lumbar spine and hip sites. Sex hormone binding globulin (SHBG) at 37nmol/L (SD 15.0) was lower in fracture cohort compared to 47.9 nmol/L (SD 19.2) (p=0.001) in control. Multiple regression revealed that the best model for prediction of fracture included SHBG, P1NP, and ultra-distal forearm aBMD. The likelihood of distal forearm fracture was decreased by 5.1% for each nmol/L increase in SHBH and by 1.4% for every mg/cm² increase in ultra-distal forearm aBMD, but increased by 6.1 % for every ng/ml increase in P1NP. Men in the highest quartile of PINP had a significantly greater likelihood of distal forearm fracture than those in the lowest quartile.

CONCLUSION

The fracture group had significantly higher PINP and βCTX compared with the control group, and these markers were negative predictors of aBMD at the total hip and forearm sites, respectively. Sclerostin was a positive predictor of the variance of spinal and hip aBMD. Likelihood of forearm fracture was best predicted by a combination of SHBG, PINP, and ultra-distal forearm aBMD. Findings of such cross-sectional data should be treated with caution, as longitudinal studies would be required to confirm or refute them.

Testosterone and Bone Health in Men: A Narrative Review

Bone fracture due to osteoporosis is an important issue in decreasing the quality of life for elderly men in the current aging society. Thus, osteoporosis and bone fracture prevention is a clinical concern for many clinicians. Moreover, testosterone has an important role in maintaining bone mineral density (BMD) among men. Some testosterone molecular mechanisms on bone metabolism have been currently established by many experimental data. Concurrent with a decrease in testosterone with age, various clinical symptoms and signs associated with testosterone decline, including decreased BMD, are known to occur in elderly men. However, the relationship between testosterone levels and osteoporosis development has been conflicting in human epidemiological studies. Thus, testosterone replacement therapy (TRT) is a useful tool for managing clinical symptoms caused by hypogonadism. Many recent studies support the benefit of TRT on BMD, especially in hypogonadal men with osteopenia and osteoporosis, although a few studies failed to demonstrate its effects. However, no evidence supporting the hypothesis that TRT can prevent the incidence of bone fracture exists. Currently, TRT should be considered as one of the treatment options to improve hypogonadal symptoms and BMD simultaneously in symptomatic hypogonadal men with osteopenia.

Does regional loss of bone density explain low trauma distal forearm fractures in men (the Mr F study)?

The pathogenesis of low trauma wrist fractures in men is not fully understood. This study found that these men have lower bone mineral density at the forearm itself, as well as the hip and spine, and has shown that forearm bone mineral density is the best predictor of wrist fracture.

INTRODUCTION

Men with distal forearm fractures have reduced bone density at the lumbar spine and hip sites, an increased risk of osteoporosis and a higher incidence of further fractures. The aim of this case-control study was to investigate whether or not there is a regional loss of bone mineral density (BMD) at the forearm between men with and without distal forearm fractures.

METHODS

Sixty-one men with low trauma distal forearm fracture and 59 age-matched bone healthy control subjects were recruited. All subjects underwent a DXA scan of forearm, hip and spine, biochemical investigations, health questionnaires, SF-36v2 and Fracture Risk Assessment Tool (FRAX). The non-fractured arm was investigated in subjects with fracture and both forearms in control subjects.

RESULTS

BMD was significantly lower at the ultradistal forearm in men with fracture compared to control subjects, in both the dominant (mean (SD) 0.386 g/cm² (0.049) versus 0.436 g/cm² (0.054), p < 0.001) and non-dominant arm (mean (SD) 0.387 g/cm² (0.060) versus 0.432 g/cm² (0.061), p = 0.001). Fracture subjects also had a significantly lower BMD at hip and spine sites compared with control subjects. Logistic regression analysis showed that the best predictor of forearm fracture was ultradistal forearm BMD (OR = 0.871 (0.805-0.943), p = 0.001), with the likelihood of fracture decreasing by 12.9% for every 0.01 g/cm² increase in ultradistal forearm BMD.

CONCLUSIONS

Men with low trauma distal forearm fracture have significantly lower regional BMD at the ultradistal forearm, which contributes to an increased forearm fracture risk. They also have generalised reduction in BMD, so that low trauma forearm fractures in men should be considered as indicator fractures for osteoporosis.

Male Hypogonadism and Osteoporosis: The Effects, Clinical Consequences, and Treatment of Testosterone Deficiency in Bone Health

It is well recognized that bone loss accelerates in hypogonadal states, with female menopause being the classic example of sex hormones affecting the regulation of bone metabolism. Underrepresented is our knowledge of the clinical and metabolic consequences of overt male hypogonadism, as well as the more subtle age-related decline in testosterone on bone quality. While menopause and estrogen deficiency are well-known risk factors for osteoporosis in women, the effects of age-related testosterone decline in men on bone health are less well known. Much of our knowledge comes from observational studies and retrospective analysis on small groups of men with variable causes of primary or secondary hypogonadism and mild to overt testosterone deficiencies. This review aims to present the current knowledge of the consequences of adult male hypogonadism on bone metabolism. The direct and indirect effects of testosterone on bone cells will be explored as well as the important differences in male osteoporosis and assessment as compared to that in females. The clinical consequence of both primary and secondary hypogonadism, as well as testosterone decline in older males, on bone density and fracture risk in men will be summarized. Finally, the therapeutic options and their efficacy in male osteoporosis and hypogonadism will be discussed.

Effect of sex-hormone levels, sex, body mass index and other host factors on human craniofacial bone regeneration with bioactive tricalcium phosphate grafts

Little is known regarding the associations between sex-hormone levels, sex, body mass index (BMI), age, other host factors and biomaterial stimulated bone regeneration in the human craniofacial skeleton. The aim of this study was to elucidate the associations between these factors and bone formation after sinus floor augmentation procedures (SFA) utilizing a bioactive tricalcium phosphate (TCP) bone grafting material. We conducted a prospective study in a human population in which 60 male and 60 female participants underwent SFA and dental implant placement using a staged approach. BMI as well as levels of serum estradiol (E2), total testosterone (TT), and the free androgen index (FAI) were measured by radioimmunoassay and electrochemoluminescent-immunoassay. At implant placement, 6 months after SFA, bone biopsy specimens were harvested for hard tissue histology, the amount of bone formation was evaluated by histomorphometry and immunohistochemical analysis of osteogenic marker expression. The Wilcoxon rank-sum U test, Spearman correlations and linear regression analysis were used to explore the association between bone formation and BMI, hormonal and other host factors. BMI and log E2 were significantly positively associated with bone formation in male individuals (p < 0.05). Histomorphometry revealed trends toward greater bone formation and osteogenic marker expression with non-smokers compared to smokers. In male patients, higher E2 levels and higher BMI enhanced TCP stimulated craniofacial i.e. intramembranous bone repair.

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.

Hypogonadism and erectile dysfunction as harbingers of systemic disease

Prescription sales of Testosterone and erectile aids such as phosphodiesterase-5 inhibitors are at an all-time high, underscoring the importance of hypogonadism (HG) and erectile dysfunction (ED) to men’s health. The effect of these debilitating conditions has a major impact on the quality of men’s lives. Some risk factors for HG or ED including aging, obesity, smoking, and a sedentary lifestyle. Notably, these are the same risk factors for several other medical co-morbidities that contribute to significant morbidity and mortality in men. HG and ED often co-exist with cardiovascular disease, diabetes, and osteoporosis. This review will explore these three co-morbidities that overlap with HG and ED, and will provide a review of their relationship with each other.

Sex hormones, sex hormone binding globulin, and vertebral fractures in older men

The association between sex hormones and sex hormone binding globin (SHBG) with vertebral fractures in men is not well studied. In these analyses, we determined whether sex hormones and SHBG were associated with greater likelihood of vertebral fractures in a prospective cohort study of community dwelling older men. We included data from participants in MrOS who had been randomly selected for hormone measurement (N=1463, including 1054 with follow-up data 4.6years later). Major outcomes included prevalent vertebral fracture (semi-quantitative grade≥2, N=140, 9.6%) and new or worsening vertebral fracture (change in SQ grade≥1, N=55, 5.2%). Odds ratios per SD decrease in sex hormones and per SD increase in SHBG were estimated with logistic regression adjusted for potentially confounding factors, including age, bone mineral density, and other sex hormones. Higher SHBG was associated with a greater likelihood of prevalent vertebral fractures (OR: 1.38 per SD increase, 95% CI: 1.11, 1.72). Total estradiol analyzed as a continuous variable was not associated with prevalent vertebral fractures (OR per SD decrease: 0.86, 95% CI: 0.68 to 1.10). Men with total estradiol values ≤17pg/ml had a borderline higher likelihood of prevalent fracture than men with higher values (OR: 1.46, 95% CI: 0.99, 2.16). There was no association between total testosterone and prevalent fracture. In longitudinal analyses, SHBG (OR: 1.42 per SD increase, 95% CI: 1.03, 1.95) was associated with new or worsening vertebral fracture, but there was no association with total estradiol or total testosterone. In conclusion, higher SHBG (but not testosterone or estradiol) is an independent risk factor for vertebral fractures in older men.

Testosterone levels increase in association with recovery from acute fracture in men

In this longitudinal case-control study, acute fracture was associated with low serum testosterone, which was transient in 43% of men. While assessment of gonadal status is part of the assessment of bone fragility, measurement of testosterone in the early period after fracture may overestimate the prevalence of androgen deficiency.

INTRODUCTION

Measurement of circulating testosterone is recommended in the evaluation of bone fragility in men. Since acute illness can transiently decrease circulating testosterone, we quantified the association of acute fracture and serum testosterone levels.

METHODS

A case-control study was conducted involving 240 men with a radiologically confirmed minimal trauma fracture presenting to a tertiary referral hospital and 89 age-matched men without a history of minimal trauma fracture serving as controls. Follow-up testosterone levels 6 months after baseline were available for 98 cases and 27 controls. Results were expressed as the median and interquartile (IQR) range.

RESULTS

Compared to controls, cases had lower total testosterone [TT, 7.2 (3.5, 10.8) vs 13.6 (10.9, 17.1) nmol/L, p < 0.001]. The 143 cases treated as inpatients had lower testosterone levels than the 97 cases treated as outpatients [TT 4.7 (2.3, 8.1) vs 10.3 (7.5, 12.7) nmol/L, p < 0.001]. Group differences in calculated free testosterone (cFT) were comparable to the group differences in TT. At follow-up, in 98 cases, median TT increased from 6.5 nmol/L (3.2, 8.5) to 9.6 nmol/L (6.9, 12.0) p < 0.0001, and SHBG remained unchanged. Of cases with low testosterone, 43% with TT <10 nmol/L and/or cFT <230 pmol/L at presentation were reclassified as androgen sufficient at follow-up. TT was unchanged in the controls.

CONCLUSIONS

Low testosterone levels in men presenting with an acute fracture may, at least in part, be due to an acute, fracture-associated, stress response. To avoid over diagnosis, evaluation for testosterone deficiency should be deferred until recovery from the acute event.

Association between polymorphisms in period genes and bone density in postmenopausal Korean women

OBJECTIVE

In the present study, we aimed to investigate the association between genetic polymorphisms in period (PER) genes and bone mineral density (BMD) in postmenopausal Korean women.

METHODS

The PER1 c.2247C> T and c.2884C> G polymorphisms; the PER2 c.661G> A and c.3731G> A polymorphisms; the PER3 c.2592G> A, c.3029C> T, c.3035C> T, and c.3083T> C polymorphisms, and the 54 bp variable number tandem repeats polymorphism were analyzed in 551 postmenopausal Korean women. Serum leptin, soluble leptin receptor, osteoprotegerin, soluble receptor activator of the nuclear factor-κB ligand, and bone markers including bone alkaline phosphatase and carboxy-terminal telopeptide of type I collagen were measured, and the lumbar spine and femoral neck BMDs were also determined.

RESULTS

The PER2 c.661G> A, PER3 c.3029C> T and c.3035C> T polymorphisms were not observed. The PER2 and PER3 polymorphisms evaluated were not related to BMD, whereas associations of the c.2247C> T and c.2884C> G polymorphisms in PER1 with the lumbar spine BMD were observed both singly and in combination. The CC haplotype homozygotes showed significantly lower lumbar spine BMD than participants with other genotypes. Additionally, 2.01-fold higher odds for osteoporosis of the lumbar spine were found in the CC haplotype homozygotes compared to women not carrying the haplotype CC allele. No significant differences in bone markers were detected according to the PER1 haplotype genotype.

CONCLUSIONS

Our results suggest that both the PER1 c.2247C> T and c.2884C> G polymorphisms may be genetic factors affecting the lumbar spine BMD in postmenopausal Korean women.

The effect of age, sex hormones, and bone turnover markers on calcaneal quantitative ultrasonometry in healthy German men

The aim of this cross-sectional study was to determine the age-dependent variations of calcaneal quantitative ultrasonometry (QUS) and the association with sex hormones and biochemical bone turnover markers in a large sample of unselected healthy German men. Bone measurements are expected to behave differently among men and women. The speed of sound (SOS), broadband ultrasound attenuation (BUA), and stiffness index (SI) of the os calcaneus were measured in 506 German men aged 20-79 yr (mean age: 45.7 yr). Additionally, follicle-stimulating hormone (FSH), luteinizing hormone (LH), estradiol, prolactin, testosterone, dehydroepiandrosterone sulfate (DHEA-S), sex hormone-binding globulin (SHBG) as well as N-terminal propeptide of human procollagen type I (PINP), C-terminal telopeptide of type I collagen (ICTP), osteocalcin, bone-specific alkaline phosphatase, and CrossLaps were measured with standardized essays and correlated with the QUS results. The QUS results comprised an overall change of 12.4%, 3.2%, and 23.2% for BUA, SOS, and SI, respectively, between the 20-29 and 70-79 yr age groups (p ≤ 0.001). The annual rate of the age-related differences was 0.33% (standard deviation [SD]: 0.31), 0.06% (SD: 0.08), and 0.53% (SD: 0.56) for BUA, SOS, and SI, respectively. Testosterone and DHEA-S were significantly associated with QUS parameters and increasing age, whereas SHBG showed an age-related increase and was inversely related with QUS values (p < 0.05). Bone turnover markers present lower values gradually, and we found a significant correlation between carboxy-terminal collagen crosslinks (CTX), osteocalcin (OC), bone alkaline phosphatase (BAP), and QUS variables (p < 0.05).

[Testosterone-deficiency as a risk factor for hip fracture in eldery men]

OBJECTIVES

Progressive loss of bone mineral density weakens the bones and increases the probability of osteoporotic fractures. It is well known that sex steroids play a role in the maintenance of bone density. This fact makes us think there might be a correlation between sex steroid levels and osteoporotic hip fractures.

MATERIAL AND METHODS

A case-control study was performed. The cases were 54 men who suffered from hip fracture. They were compared with 54 age-matched male control subjects. Levels of total testosterone, sex hormone binding globuline, albumin and oestradiol were measured in all subjects in order to calculate free testosterone and bio-testosterone levels.

RESULTS

Men who suffered from hip fracture had lower serum total testosterone (8.74 nmol/L versus 11.16 nmol/L; p=0.116) and lower free testostenone (155.1pmol/L versus 204.4pmol/L; p=0.02) than control subjects. Bio-testosterone levels were lower in patients with hip fracture (2.69 nmol/L versus 3.89 nmol/L; p=0.002), being the latter the best fracture predictor (OR: 1.58).

CONCLUSIONS

In our study population, men with hip fractures had significantly lower levels of calculated free testosterone and bio-testosterone. These findings suggest that free testosterone and bio-testosterone levels are independent predictors for osteoporotic hip fracture in eldery men.

SHBG levels are associated with bone loss and vertebral fractures in patients with prostate cancer

SUMMARY

Fractures are increased among prostate cancer patients. No data have been reported in patients with prostate cancer about the relation between serum sex hormone-binding globulin (SHBG) and bone metabolism. We found that SHBG levels were inversely related to bone mass and vertebral fractures in this population.

INTRODUCTION

Fractures are increased among prostate cancer patients, especially those on androgen deprivation therapy (ADT), but few data are available on the role of SHBG in their bone status. Our objective was to analyze the relation between serum SHBG and bone metabolism in prostate cancer patients.

METHODS

This is a cross-sectional study including 91 subjects with prostate cancer (54 % with ADT). We measured serum levels of SHBG and sex steroids, bone mineral density (BMD) by dual-energy X-ray absorptiometry, and prevalent radiographic vertebral fractures.

RESULTS

SHBG levels were inversely related to BMD (femoral neck: r = -0.299, p = 0.00; total hip: r = -0.259, p = 0.019). Subjects with osteoporosis had higher SHBG concentrations than patients without osteoporosis (60.97 ± 39.56 vs 44.45 ± 23.32 nmol/l, p = 0.022). Patients with SHBG levels in the first quartile (>57.6 nmol/l) had an odds ratio (OR) for osteoporosis of 2.59 (95 % CI, 1.30-5.12; p = 0.009) compared with patients with lower SHBG levels. In patients with SHBG >57.6 nmol/l, the OR for vertebral fractures was 2.34 (95 % CI, 1.15-4.78; p = 0.034). The calculated OR was higher after adjustment for age (OR, 5.16; 95 % CI, 1.09-24.49; p = 0.039), estrogens (OR, 6.45; 95 % CI, 1.44-28.95; p = 0.023), and androgens (OR, 5.51; 95 % CI, 1.36-22.37; p = 0.017).

CONCLUSIONS

In prostate cancer patients, SHBG levels were inversely related to bone mass and vertebral fractures. Determination of the serum SHBG level may constitute a useful and straightforward marker for predicting the severity of osteoporosis in these patients.

Diagnostic performance of the urinary deoxypyridinoline in spinal tuberculosis

This study investigated the diagnostic significance of urinary deoxypyridinoline measurement as a screening tool for spinal tuberculosis in patients with pulmonary tuberculosis.Urinary deoxypyridinoline levels were measured by automated chemiluminescence immunoassay and automated chemistry methods in patients with spinal (n=33) and pulmonary tuberculosis (n=33) and in healthy controls (n=30). Urinary deoxypyridinoline was divided by urinary creatine to exclude the factors of body mass index and urine dilution. The results underwent validity analysis. The measurements of urinary deoxypyridinoline in the spinal tuberculosis, pulmonary tuberculosis, and control groups were 14.9 ± 9.8, 6.4 ± 2.6, and 6.3 ± 2.0 μmol/molCr, respectively. Compared with the other 2 groups, the urinary deoxypyridinoline level in the spinal tuberculosis group was significantly increased (P=.001 and P=.000, respectively). However, urinary deoxypyridinoline levels were not significantly different between the pulmonary tuberculosis and control groups (P=.751). The receiver operating characteristic curve in the spinal tuberculosis group was 0.83. For deoxypyridinoline, the sensitivity (88%) and specificity (95%) were seen at the cutoff level of 8.0 μmol/molCr. The false positive and false negative were 12% and 5%, respectively. Diagnostic validity of the method was 93%.Bone metabolism alteration occurs during the progression of spinal tuberculosis, which can be reflected by the sensitivity and specificity of urinary deoxypyridinoline. The detection of urinary deoxypyridinoline is a benefit of screening patients with pulmonary tuberculosis for spinal tuberculosis.

The relationship between sex steroids, bone turnover and vertebral fracture prevalence in asymptomatic men

OBJECTIVE

To examine the association between oestradiol (E2), testosterone (T), SHBG levels and vertebral fractures' (VFs) prevalence in asymptomatic men.

METHODS

The study cohort consists of a population of 112 consecutive men (mean±SD (range) age, weight and BMI were 62.9±9.2 (41-84) years, 75.0±13.8 (45-120) kgs and 26.4±4.7 (18.0-39.6) kg/m(2), respectively). Lateral vertebral fracture assessment (VFA) images and scans of the lumbar spine and proximal femur were obtained using a GE Healthcare Lunar Prodigy densitometer. VFs were defined using a combination of Genant semiquantitative approach and morphometry. Serum levels of T, E2, CTx and osteocalcine were measured. Free androgen index (FAI) and free estradiol index (FEI) were calculated respectively from the ratio of serum T and E2 to SHBG.

RESULTS

Among the 112 men, 38 (33.9%) had densitometric osteoporosis, and on VFA, VFs were identified in 60 (53.5%): 24 men had grade 1 and 36 had grade 2 or 3 VFs (32.1%). Men with VFs weighted less and had a statistically significant lower lumbar spine and total hip BMD and T-scores than those without a VFA-identified vertebral fracture. Levels of osteocalcine, CTx, and SHBG were statistically higher in men with grades 2 and 3 VFs than men with grade 1 VFs and those without VFs whereas FAI and FEI levels were significantly lower. Comparison of patients according to quartiles of SHBG levels showed that men in the highest quartile were older, had a lower lumbar spine and total hip BMD and a higher prevalence of osteoporosis and VFs. They had also higher levels of CTx. Stepwise regression analysis showed that the osteoporotic status and SHBG was independently associated to the presence of VFs.

CONCLUSION

Men with asymptomatic densitometric VFs have lower BMD than subjects without VFs. They have evidence of higher SHBG levels and hence lower free sex steroids as well as increased bone resorption. This study confirms that BMD and CTx are the most important determinant of asymptomatic VFs, and that SHBG is an independent risk factor that must be taken into account.

Adverse effects of corticosteroids on bone metabolism: a review

Glucocorticoid (GC) exposure is the most common etiology of drug-induced (secondary) osteoporosis. Twenty percent of all cases of osteoporosis have been attributed to GC exposure. Significant risk factors for the development of fractures after GC exposure include age older than 65 years, prolonged GC exposure (>3 months), positive family history of osteoporosis, and low calcium intake. GCs are known to inhibit bone remodeling and to increase fracture risk. GC exposure alters the fragile balance between osteoclast and osteoblast activity in bone metabolism. GC stimulates osteoclast-mediated bone resorption and reduces osteoblast-mediated bone formation, which results in increased overall net bone resorption. Specifically, the 2 main effects of GCs on bone metabolism are (1) inducing apoptosis in osteoblasts and osteocytes, thereby decreasing bone formation, and (2) prolonging the lifespan of osteoclasts and increasing bone resorption. The risk of fracture decreases 3 months after cessation of GC therapy; thus, a 3-month period may be ideal between GC exposures in patients at high risk for the development of osteoporosis. Patients managed with GCs who are at high risk for the development of secondary osteoporosis should have appropriate diagnostic testing; pre-GC exposure medication management (ie, use of bisphosphonates, human parathyroid hormone); and a limitation of GC therapy, with a wait period of 3 months between GC exposures if possible.

Fragility fractures in men with idiopathic osteoporosis are associated with undermineralization of the bone matrix without evidence of increased bone turnover

The pathogenesis of primary osteoporosis in younger individuals is still elusive. An important determinant of the biomechanical competence of bone is its material quality. In this retrospective study we evaluated bone material quality based on quantitative backscattered electron imaging to assess bone mineralization density distribution (BMDD) in bone biopsies of 25 male patients (aged 18-61 years) who sustained fragility fractures but were otherwise healthy. BMDD of cancellous bone was compared with previously established adult reference data. Complementary information was obtained by bone histomorphometry. The histomorphometric results showed a paucity of osteoblasts and osteoclasts on the bone surface in the majority of patients. BMDD revealed a significant shift to lower mineralization densities for cancellous bone values: CaMean (weighted mean Ca content, -5.9%), CaPeak (mode of the BMDD, -5.6%), and CaHigh (portion of fully mineralized bone, -76.8%) were decreased compared to normative reference; CaWidth (heterogeneity in mineralization, +18.5%) and CaLow (portion of low mineralized bone, +68.8; all P < 0.001) were significantly increased. The shift toward lower mineral content in the bone matrix in combination with reduced indices of bone formation and bone resorption suggests an inherent mineralization defect leading to undermineralized bone matrix, which might contribute to the susceptibility to fragility fractures of the patients. The alteration in bone material might be related to osteoblastic dysfunction and seems fundamentally different from that in high bone turnover osteoporosis with a negative bone balance.

From estrogen-centric to aging and oxidative stress: a revised perspective of the pathogenesis of osteoporosis

Estrogen deficiency has been considered the seminal mechanism of osteoporosis in both women and men, but epidemiological evidence in humans and recent mechanistic studies in rodents indicate that aging and the associated increase in reactive oxygen species (ROS) are the proximal culprits. ROS greatly influence the generation and survival of osteoclasts, osteoblasts, and osteocytes. Moreover, oxidative defense by the FoxO transcription factors is indispensable for skeletal homeostasis at any age. Loss of estrogens or androgens decreases defense against oxidative stress in bone, and this accounts for the increased bone resorption associated with the acute loss of these hormones. ROS-activated FoxOs in early mesenchymal progenitors also divert ss-catenin away from Wnt signaling, leading to decreased osteoblastogenesis. This latter mechanism may be implicated in the pathogenesis of type 1 and 2 diabetes and ROS-mediated adverse effects of diabetes on bone formation. Attenuation of Wnt signaling by the activation of peroxisome proliferator-activated receptor gamma by ligands generated from lipid oxidation also contributes to the age-dependent decrease in bone formation, suggesting a mechanistic explanation for the link between atherosclerosis and osteoporosis. Additionally, increased glucocorticoid production and sensitivity with advancing age decrease skeletal hydration and thereby increase skeletal fragility by attenuating the volume of the bone vasculature and interstitial fluid. This emerging evidence provides a paradigm shift from the "estrogen-centric" account of the pathogenesis of involutional osteoporosis to one in which age-related mechanisms intrinsic to bone and oxidative stress are protagonists and age-related changes in other organs and tissues, such as ovaries, accentuate them.