Influence of age and sex steroids on bone density and geometry in middle-aged and elderly European men

Causality between Sex Hormones and Bone Mineral Density in Childhood: Age- and Tanner-Stage-Matched Sex Hormone Level May Be an Early Indicator of Pediatric Bone Fragility

This study aimed to investigate the impact of hypogonadism on bone mineral density (BMD) in children and adolescents with chronic diseases to determine the relationship between sex hormones and BMD. This retrospective study included 672 children and adolescents with chronic diseases such as hemato-oncologic, rheumatoid, gastrointestinal, and endocrinologic diseases. The relationship between the sex- and Tanner-stage-matched Z-scores for sex hormones and the sex- and age-matched lumbar spine BMD (LSBMD) Z-scores was evaluated. Adjustments were made for confounders such as underlying diseases, age at diagnosis, and age- and sex-matched body mass index Z-scores. Patients had a mean LSBMD Z-score of -0.55 ± 1.31. In the multivariate regression analysis, male testosterone showed a positive association with the LSBMD Z-score (p < 0.001), whereas female estradiol, luteinizing hormone, and follicular-stimulating hormone showed no significant association with the LSBMD Z-scores. In the male group, the testosterone level was associated with LSBMD Z-scores > -1.0 (p < 0.001), > -2.0 (p < 0.001), and > -3.0 (p = 0.002), while the estradiol level was associated with LSBMD Z-scores > -2.0 (p = 0.001) and > -3.0 (p = 0.002) in the female group. In conclusion, sex hormones are associated with BMD in children and adolescents with chronic diseases. Therefore, various measures may be necessary to predict future skeletal problems and improve bone health in these patients.

Bone Turnover Markers in Children: From Laboratory Challenges to Clinical Interpretation

Bone turnover markers (BTMs) have been developed many years ago to study, in combination with imaging techniques, bone remodeling in adults. In children and adolescents, bone metabolism differs from adults since it implies both growth and bone remodeling, suggesting an age- and gender-dependent BTM concentration. Therefore, specific studies have evaluated BTMs in not only physiological but also pathological conditions. However, in pediatrics, the use of BTMs in clinical practice is still limited due to these many children-related specificities. This review will discuss about physiological levels of BTMs as well as their modifications under pathological conditions in children and adolescents. A focus is also given on analytical and clinical challenges that restrain BTM usefulness in pediatrics.

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.

Effects of estradiol on bone in men undergoing androgen deprivation therapy: a randomized placebo-controlled trial

OBJECTIVE

In men, many effects of testosterone (T) on the skeleton are thought to be mediated by estradiol (E2), but trial evidence is largely lacking. This study aimed to determine the effects of E2 on bone health in men in the absence of endogenous T.

DESIGN

This study is a 6-month randomized, placebo-controlled trial with the hypothesis that E2 would slow the decline of volumetric bone mineral density (vBMD) and bone microstructure, maintain areal bone mineral density (aBMD), and reduce bone remodelling.

METHODS

78 participants receiving androgen deprivation therapy for prostate cancer were randomized to 0.9 mg of 0.1% E2 gel daily or matched placebo. The outcome measures were vBMD and microarchitecture at the distal tibia and distal radius by high-resolution peripheral quantitative CT, aBMD at the spine and hip by dual-energy x-ray absorptiometry, and serum bone remodelling markers.

RESULTS

For the primary endpoint, total vBMD at the distal tibia, there was no significant difference between groups, mean adjusted difference (MAD) 2.0 mgHA/cm3 (95% CI: -0.8 to 4.8), P = 0.17. Cortical vBMD at the distal radius increased in the E2 group relative to placebo, MAD 14.8 mgHA/cm3 (95% CI: 4.5 to 25.0), P = 0.005. Relative to placebo, E2 increased estimated failure load at tibia, MAD 250 N (95% CI: 36 to 465), P = 0.02, and radius, MAD 193 N (95% CI: 65 to 320), P = 0.003. Relative to placebo, E2 increased aBMD at the lumbar spine, MAD 0.02 g/cm2 (95% CI: 0.01 to 0.03), P = 0.01, and ultra-distal radius, MAD 0.01 g/cm2 (95% CI: 0.00 to 0.02), P = 0.01, and reduced serum bone remodelling markers.

CONCLUSION

Relative to placebo, E2 treatment increases some measures of bone density and bone strength in men and reduces bone remodelling, effects that occur in the absence of endogenous T.

The relationship between circulating hormone levels, bone turnover markers and skeletal development in healthy boys differs according to maturation stage

INTRODUCTION

This study investigates peri-pubertal changes in bone turnover markers, Wnt-signalling markers, insulin-like growth factor-1 (IGF-1) and sex steroid levels, and how they reflect skeletal development in peri-pubertal boys.

MATERIALS AND METHODS

Population-based study in 118 peri-pubertal boys from the NINIOS cohort (age range at baseline 5.1-17.3 years) with repeated measurements at baseline and after two years. Serum levels of the classical bone turnover markers (BTM) procollagen type 1 N-terminal propeptide and carboxy-terminal collagen crosslinks, as well as sex-hormone binding globulin, IGF-1, osteoprotegerin, sclerostin and dickkopf-1 were measured using immunoassays. Sex steroids (estradiol, testosterone, and androstenedione) were measured using mass spectrometry and free fractions calculated. Dual energy x-ray absorptiometry was used for bone measurements at the lumbar spine and whole body. Volumetric bone parameters and bone geometry at the proximal and distal radius were assessed by peripheral QCT. Pubertal development was categorized based on Tanner staging.

RESULTS

During puberty, sex steroid and IGF-1-levels along with most parameters of bone mass and bone size increased every next Tanner stage. In contrast, classical bone turnover markers and sclerostin peaked around mid-puberty, with subsequent declines towards adult values in late puberty. Especially classical BTM and sex steroid levels showed consistent associations with areal and volumetric bone parameters and bone geometry. However, observed associations differed markedly according to pubertal stage and skeletal site.

CONCLUSION

Serum levels of sex steroids, IGF-1 and bone metabolism markers reflect skeletal development in peri-pubertal boys. However, skeletal development during puberty is nonlinear, and the relations between skeletal indices and hormonal parameters are nonlinear as well, and dependent on the respective maturation stage and skeletal site.

Role of sex steroids hormones in the regulation of bone metabolism in men: Evidence from clinical studies

Sex steroids regulate bone metabolism in young men during growth and consolidation. Their deficit during growth compromises longitudinal and radial growth of bones and has a negative impact on body height, bone width, peak areal bone mineral density (aBMD) and bone microarchitecture. In older men, the deficit of sex steroid hormones (mainly 17β-oestradiol) contributes to high bone turnover rate, low aBMD, poor bone microarchitecture, low estimated bone strength, accelerated bone loss and rapid decline of bone microarchitecture. The role of 17β-oestradiol is confirmed by the case of men with congenital oestrogen receptor deficit and with congenital aromatase deficiency. 17β-oestradiol inhibits bone resoption, whereas both hormones regulate bone formation. However, the associations are weak. Prospective data on the utility of blood 17β-oestradiol or testosterone for fracture risk assessment are inconsistent. Men with hypogonadism have decreased aBMD and poor bone microarchitecture. In men with hypogonadism, testosterone replacement therapy increases aBMD and improves bone microarchitecture. In men with prostate cancer, androgen deprivation therapy (gonadoliberin analogues) induces rapid bone loss and severe deterioration of bone microarchitecture.

The importance of association between sexsteroids deficiency, reduction of bone mineral density and falling risk in men with implications in medical rehabilitation

Introduction. Endocrino-metabolic rehabilitation represent one of the most complex sector in clinical medicine, regarding functional rehabilitation. Sex hormones deficiency plays an important role in the etiology of osteoporosis in men. At the same time, with age, the trophic role of androgens on muscle decreases and determines an increased frequency of falls. The objective of our study is to determine the association between sexsteroids deficiency, reduction of bone mineral density (BMD) and falling risk in men. Methods. Our retrospective cross-sectional study included 146 men aged between 65–85 years with low BMD (study group) and 121 men with normal BMD (control group). The measurement of Total testosterone (Tt), free testosterone (Tf) and estradiol (E2) serum levels was performed using the immunoassay or the immunoenzymatic methods. Femoral neck and lumbar spine BMD was determined using Dual-energy X-ray absorptiometry (DEXA). The risk of falls was assessed by Tandem Standing, Up & Go, Chair – Rising and walking speed tests. Results. We found a significantly association between Tf and E2 deficiency and low BMD (p=0.007). Also, in men with reduced BMD (study group) we observed significant lower levels of Tf (p<0.001) and E2 (p=0.003) compared to control group. E2 deficiency was associated significantly with low BMD and increased fall risk (p=0.001). At the same time the results highlighted significant lower levels of Tf in patients with BMD reduction and increased risk of falls (p=0.002). Tt deficiency was not associated with BMD reduction (p=0.088) or increased risk of falling (p=0.277). Conclusions. This research revealed a significant association between male sexsteroids deficiency, low BMD and increase of falling risk, with implications in rehabilitation program. The risk of ostoporosis and for falling in man can be estimated by determining serum Tf and E2 levels. Keywords: sexsteroids deficiency; bone mineral density; falling risk,

Late-onset Hypogonadism: Bone health

BACKGROUND

Bone health is underdiagnosed and undermanaged in men. Bone loss occurs in men with hypogonadism and in aging men. Thus, patients with a diagnosis of late-onset hypogonadism (LOH) are at risk of osteoporosis and osteoporotic fractures.

OBJECTIVES

To provide an update on research data and clinical implications regarding bone health in men with LOH by reviewing literature articles on this issue.

MATERIALS AND METHODS

A thorough search of listed publications in PubMed on bone health in older men with hypogonadism was performed, and other articles derived from these publications were further identified.

RESULTS

Late-onset Hypogonadism may be associated with reduced bone mineral density (BMD). In a pathophysiological perspective, the detrimental effects of testosterone (T) deficiency on BMD are partly ascribed to relative estrogen deficiency and both serum T and serum estradiol (E2) need to be above 200 ng/dL and 20 pg/mL to prevent bone loss. The effects of exogenous T on BMD are controversial, but most of the studies confirm that testosterone replacement therapy (TRT) increases BMD and prevents further bone loss in men with hypogonadism. No data are available on TRT and the prevention of fractures.

DISCUSSION AND CONCLUSION

In men with documented LOH, a specific clinical workup should be addressed to the diagnosis of osteoporosis in order to program subsequent follow-up and consider specific bone active therapy. TRT should be started according to guidelines of male hypogonadism while keeping in mind that it may also have positive effects also on bone health in men with LOH.

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.

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.

Aging and sex hormones in males

Several large cohort studies have disclosed the trajectories of sex steroids changes overtime in men and their clinical significance. In men the slow, physiological decline of serum testosterone (T) with advancing age overlaps with the clinical condition of overt, pathological hypogonadism. In addition, the increasing number of comorbidities, together with the high prevalence of chronic diseases, all further contribute to the decrease of serum T concentrations in the aging male. For all these reasons both the diagnosis of late-onset hypogonadism (LOH) in men and the decision about starting or not T replacement treatment remain challenging. At present, the biochemical finding of T deficiency alone is not sufficient for diagnosing hypogonadism in older men. Coupling hypogonadal symptoms with documented low serum T represents the best strategy to refine the diagnosis of hypogonadism in older men and to avoid unnecessary treatments.

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.

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.

Age-dependent impact of inferior alveolar nerve transection on mandibular bone metabolism and the underlying mechanisms

Aging is associated with peripheral nerve degradation and bone destruction. The aim of the study is to elucidate the influence of sensory denervation on bone metabolism in different age groups by establishing a modified unilateral inferior alveolar nerve transection (IANT) model. The rats, divided into young, middle-aged and aged group, were sacrificed at 1, 2, 4 and 8 weeks after right IANT. The histological changes of mandibles were analyzed by fluorescent double labeling, micro-CT, HE, TRAP and anti-CGRP immunohistochemical staining. Molecular mechanisms underlying the changes were analyzed by qPCR and western blot. Differences between the test and control side were evaluated by paired-samples t test. The Friedman test and separate Wilcoxon signed-rank tests were applied to analyze age-dependent difference. The impact of IANT was the most intensive in developing bone, the most persistent in full grown bone and the faintest in the aged bone. The role of IAN in keeping homeostasis was closely related to the anabolic effect of CGRP, which suppressed the number of osteoclasts through OPG/RANKL ratio and controlled growth factors expression like BMP2. This study contributes to a better understanding of the molecular mechanisms of CGRP in vivo and the relationship among sensory nerve, bone metabolism and aging.

Life Course Dietary Patterns and Bone Health in Later Life in a British Birth Cohort Study

Evidence for the contribution of individual foods and nutrients to bone health is weak. Few studies have considered hypothesis-based dietary patterns and bone health. We investigated whether a protein-calcium-potassium-rich (PrCaK-rich) dietary pattern over the adult life course, was positively associated with bone outcomes at 60 to 64 years of age. Diet diaries were collected at ages 36, 46, 53, and 60 to 64 years in 1263 participants (661 women) from the MRC National Survey of Health and Development. DXA and pQCT measurements were obtained at age 60 to 64 years, including size-adjusted bone mineral content (SA-BMC) and volumetric bone mineral density (vBMD). A food-based dietary pattern best explaining dietary calcium, potassium, and protein intakes (g/1000 kcal) was identified using reduced rank regression. Dietary pattern Z-scores were calculated for each individual, at each time point. Individual trajectories in dietary pattern Z-scores were modeled to summarize changes in Z-scores over the study period. Regression models examined associations between these trajectories and bone outcomes at age 60 to 64 years, adjusting for baseline dietary pattern Z-score and other confounders. A consistent PrCaK-rich dietary pattern was identified within the population, over time. Mean ± SD dietary pattern Z-scores at age 36 years and age 60 to 64 years were -0.32 ± 0.97 and 2.2 ± 1.5 (women) and -0.35 ± 0.98 and 1.7 ± 1.6 (men), respectively. Mean trajectory in dietary pattern Z-scores ± SD was 0.07 ± 0.02 units/year. Among women, a 0.02-SD unit/year higher trajectory in dietary pattern Z-score over time was associated with higher SA-BMC (spine 1.40% [95% CI, 0.30 to 2.51]; hip 1.35% [95% CI, 0.48 to 2.23]), and vBMD (radius 1.81% [95% CI, 0.13 to 3.50]) at age 60 to 64 years. No statistically significant associations were found in men. During adulthood, an increasing score for a dietary pattern rich in protein, calcium, and potassium was associated with greater SA-BMC at fracture-prone sites in women. This study emphasizes the importance of these nutrients, within the context of the whole diet, to bone health. © 2016 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals, Inc. on behalf of American Society for Bone and Mineral Research (ASBMR).

Bone Mineral Density in the Noninstitutionalized Elderly: Influence of Sociodemographic and Anthropometric Factors

Objective. Analysis of bone mineral density (BMD) in the elderly and its associated factors according to sex. Methods. A cross-sectional study is presented herein, with a random sample of 132 noninstitutionalized elderly people. Individuals who did not use diuretics were excluded. BMD was obtained from examination of total body densitometry and its association with sociodemographic variables, lifestyle, anthropometric, and body composition was verified. Results. Mean BMD for men was 1.17 ± 0.12 g/cm(2) and for women was 1.04 ± 0.11 g/cm(2). Higher education was associated with higher BMD values in men (p < 0.05). There was a reduction in BMD in the age group 75-79 years of age in women and over 80 years of age in men (p < 0.05). Underweight was associated with significantly low BMD for both sexes (p < 0.01), while normal weight was associated with low BMD in women (p < 0.001). Discussion. The elderly with low schooling and in older age groups are more probable to also present low BMD. Lower levels of body mass index also indicated towards low BMD.

Reproductive Hormones and Longitudinal Change in Bone Mineral Density and Incident Fracture Risk in Older Men: The Concord Health and Aging in Men Project

The objectives of this study were to examine relationships between baseline levels of reproductive hormones in older men and (1) change in bone mineral density (BMD) over 5 years and (2) incident fractures over an average of 6 years' follow-up. A total of 1705 men aged 70 years and older from the Concord Health and Ageing in Men Project (CHAMP) study were assessed at baseline (2005-2007), 2 years follow-up (2007-2009), and 5 years follow-up (2010-2013). At baseline, testosterone (T), dihydrotestosterone (DHT), estradiol (E2), and estrone (E1) were measured by liquid chromatography-tandem mass spectrometry (LC-MS/MS), and sex hormone-binding globulin (SHBG), luteinizing hormone (LH), and follicle-stimulating hormone (FSH) by immunoassay. Hip BMD was measured by dual X-ray absorptiometry (DXA) at all three time-points. Fracture data were collected at 4-monthly phone calls and verified radiographically. Statistical modeling was by general estimating equations and Cox model regression. Univariate analyses revealed inverse associations for serum SHBG, FSH, and LH and positive association for E1 but not DHT or E2 with BMD loss at the hip across the three time points. Serum levels of SHBG (β = -0.071), FSH (β = -0.085), LH (β = -0.070), and E1 (β = 0.107) remained significantly associated with BMD loss in multivariate-adjusted models; however, we were unable to identify any thresholds for accelerated BMD loss according to reproductive steroids. Incident fractures (all, n = 171; hip, n = 44; and nonvertebral, n = 139) were all significantly associated with serum SHBG, FSH, and LH levels in univariate models but none remained significantly associated in multivariate-adjusted model. Serum T, DHT, E2, and E1 levels were not associated with incident fractures in univariate or multivariate-adjusted analyses. In older men, lower serum SHBG, FSH, and LH and higher E1 levels protected against loss of BMD without increasing fracture rate. This means these reproductive variables may be considered as novel biomarkers of bone health during male aging.

High aromatase activity in hypogonadal men is associated with higher spine bone mineral density, increased truncal fat and reduced lean mass

OBJECTIVE

Because the aromatase enzyme catalyzes the conversion of testosterone to estradiol (E2), the activity of this enzyme could be important in the musculoskeletal health of men with low testosterone. The objective of the present study is to determine the influence of aromatase activity on the bone mineral density (BMD) and body composition of patients with hypogonadism.

DESIGN

Cross-sectional study.

METHODS

The baseline data of 90 patients between 40 and 74 years old who participated in a genetic study of response to testosterone therapy in men with low testosterone (i.e., <300 ng/dl) were analyzed. BMD and body composition were measured by dual-energy X-ray absorptiometry. Serum testosterone was measured by automated immunoassay, E2 was measured by ultrasensitive enzyme immunoassay, and sex hormone-binding globulin was measured by enzyme immunoassay.

RESULTS

Men in the highest tertile of E2 to testosterone ratio (E2:T) had the highest spine BMD (P ≤ 0.037), highest truncal fat (P=0.046), and lowest truncal lean body mass (P=0.045). A similar pattern was observed in the upper extremities; that is, fat mass significantly increased (P=0.047), whereas lean mass significantly decreased (P=0.034) with increasing E2:T tertiles.

CONCLUSION

The present findings suggest that in men with hypogonadism, aromatase activity could be an important determinant of musculoskeletal health. Men with high aromatase activity are able to maintain a higher BMD despite low circulating testosterone, but they have lower lean and higher truncal fat mass as compared to those with lower aromatase activity.

Interaction between bone and muscle in older persons with mobility limitations

Aging is associated with a progressive loss of bone-muscle mass and strength. When the decline in mass and strength reaches critical thresholds associated with adverse health outcomes, they are operationally considered geriatric conditions and named, respectively, osteoporosis and sarcopenia. Osteoporosis and sarcopenia share many of the same risk factors and both directly or indirectly cause higher risk of mobility limitations, falls, fractures and disability in activities of daily living. This is not surprising since bones adapt their morphology and strength to the long-term loads exerted by muscle during anti-gravitational and physical activities. Non-mechanical systemic and local factors also modulate the mechanostat effect of muscle on bone by affecting the bidirectional osteocyte-muscle crosstalk, but the specific pathways that regulate these homeostatic mechanisms are not fully understood. More research is required to reach a consensus on cut points in bone and muscle parameters that identify individuals at high risk for adverse health outcomes, including falls, fractures and disability. A better understanding of the muscle-bone physiological interaction may help to develop preventive strategies that reduce the burden of musculoskeletal diseases, the consequent disability in older persons and to limit the financial burden associated with such conditions. In this review, we summarize age-related bone-muscle changes focusing on the biomechanical and homeostatic mechanisms that explain bone-muscle interaction and we speculate about possible pathological events that occur when these mechanisms become impaired. We also report some recent definitions of osteoporosis and sarcopenia that have emerged in the literature and their implications in clinical practice. Finally, we outline the current evidence for the efficacy of available anti-osteoporotic and proposed antisarcopenic interventions in older persons.

The endocrine role of estrogens on human male skeleton

Before the characterization of human and animal models of estrogen deficiency, estrogen action was confined in the context of the female bone. These interesting models uncovered a wide spectrum of unexpected estrogen actions on bone in males, allowing the formulation of an estrogen-centric theory useful to explain how sex steroids act on bone in men. Most of the principal physiological events that take place in the developing and mature male bone are now considered to be under the control of estrogen. Estrogen determines the acceleration of bone elongation at puberty, epiphyseal closure, harmonic skeletal proportions, the achievement of peak bone mass, and the maintenance of bone mass. Furthermore, it seems to crosstalk with androgen even in the determination of bone size, a more androgen-dependent phenomenon. At puberty, epiphyseal closure and growth arrest occur when a critical number of estrogens is reached. The same mechanism based on a critical threshold of serum estradiol seems to operate in men during adulthood for bone mass maintenance via the modulation of bone formation and resorption in men. This threshold should be better identified in-between the ranges of 15 and 25 pg/mL. Future basic and clinical research will optimize strategies for the management of bone diseases related to estrogen deficiency in men.

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.

Association between sex steroid levels and bone microarchitecture in men: the STRAMBO study

CONTEXT

Data on the association between bone microarchitecture assessed by high-resolution peripheral quantitative computed tomography (HR-pQCT) and sex steroids in men are scarce.

OBJECTIVE

Our aim was to determine the association between serum sex steroids and bone microarchitecture assessed by HR-pQCT in men.

DESIGN

This is a cross-sectional analysis in the Structure of the Aging Men's Bones cohort.

SETTING

The cohort was recruited from the general population.

PARTICIPANTS

We examined 1169 male volunteers aged 20-87 years. No specific exclusion criteria were used.

INTERVENTIONS

We collected blood samples and performed HR-pQCT at the distal radius and distal tibia.

MAIN OUTCOME MEASURES

We tested the hypothesis that low sex steroid levels are associated with poor bone microarchitecture in men.

RESULTS

Men aged younger than 65 years with bioavailable 17β-estradiol (bio-17β-E2) levels of14.4 pmol/L or less had higher cross-sectional and trabecular areas vs men with bio-17β-E2 greater than 14.4 pmol/L. In men aged 65 years or older, the higher the apparent free T concentration (AFTC), the higher was the distal tibia cortical density (P < .05). Cortical density and thickness as well as total and trabecular density increased with higher bio-17β-E2 levels. Similar results were found after adjustment for limb length and body height. Men with low AFTC and low bio-17β-E2 levels had lower cortical density and thickness at both skeletal sites compared with the reference group. In men with AFTC less than 272 pmol/L, those with low bio-17β-E2 less than 25 pmol/L had lower cortical density and thickness at both skeletal sites vs men having higher bio-17β-E2 levels.

CONCLUSION

In men aged 65 years and older, low bio-17β-E2 levels were associated with poor cortical bone status and, to smaller extent, lower trabecular density.

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.

Impact of Charcot neuroarthropathy on metatarsal bone mineral density and geometric strength indices

Charcot neuroarthropathy (CN), an inflammatory condition characterized by rapid and progressive destruction of pedal bones and joints, often leads to deformity and ulceration in individuals with diabetes mellitus (DM) and peripheral neuropathy (PN). Repetitive, unperceived joint trauma may trigger initial CN damage, causing a proinflammatory cascade that can result in osteolysis and contribute to subsequent neuropathic fracture. We aimed to characterize osteolytic changes related to development and progression of CN by measuring bone mineral density (BMD) and geometric strength indices using volumetric quantitative computed tomography. Twenty individuals with DM+PN were compared to twenty age-, sex-, and race-matched individuals with DM+PN and acute CN. We hypothesized that individuals with acute CN would have decreased BMD and decreased total area, cortical area, minimum section modulus, and cortical thickness in the diaphysis of the second and fifth metatarsals. Results showed BMD was lower in both involved and uninvolved feet of CN participants compared to DM+PN participants, with greater reductions in involved CN feet compared to uninvolved CN feet. There was a non-significant increase in total area and cortical area in the CN metatarsals, which helps explain the finding of similar minimum section modulus in DM+PN and CN subjects despite the CN group's significantly lower BMD. Larger cortical area and section modulus are typically considered signs of greater bone strength due to higher resistance to compressive and bending loads, respectively. In CN metatarsals, however, these findings may reflect periosteal woven bone apposition, i.e., a hypertrophic response to injury rather than increased fracture resistance. Future research using these techniques will aid further understanding of the inflammation-mediated bony changes associated with development and progression of CN and other diseases.

Predicting ex vivo failure loads in human metatarsals using bone strength indices derived from volumetric quantitative computed tomography

We investigated the capacity of bone quantity and bone geometric strength indices to predict ultimate force in the human second metatarsal (Met2) and third metatarsal (Met3). Intact lower extremity cadaver samples were measured using clinical, volumetric quantitative computed tomography (vQCT) with positioning and parameters applicable to in vivo scanning. During processing, raw voxel data (0.4mm isotropic voxels) were converted from Hounsfield units to apparent bone mineral density (BMD) using hydroxyapatite calibration phantoms to allow direct volumetric assessment of whole-bone and subregional metatarsal BMD. Voxel data were realigned to produce cross-sectional slices perpendicular to the longitudinal axes of the metatarsals. Average mid-diaphyseal BMD, bone thickness, and buckling ratio were measured using an optimized threshold to distinguish bone from non-bone material. Minimum and maximum moments of inertia and section moduli were measured in the mid-diaphysis region using both a binary threshold for areal, unit-density measures and a novel technique for density-weighted measures. BMD and geometric strength indices were strongly correlated to ultimate force measured by ex vivo 3-point bending. Geometric indices were more highly correlated to ultimate force than was BMD; bone thickness and density-weighted minimum section modulus had the highest individual correlations to ultimate force. Density-weighted geometric indices explained more variance than their binary analogs. Multiple regression analyses defined models that predicted 85-89% of variance in ultimate force in Met2 and Met3 using bone thickness and minimum section modulus in the mid-diaphysis. These results have implications for future in vivo imaging to non-invasively assess bone strength and metatarsal fracture risk.

Endogenous testosterone, muscle strength, and fat-free mass in men with chronic kidney disease

OBJECTIVE

Testosterone deficiency is a common finding in men with chronic kidney disease (CKD). Testosterone is thought to play an important anabolic role in muscle synthesis, and muscle wasting is an important and deleterious characteristic of protein-energy wasting (PEW) in CKD. It is presently unknown if reduced endogenous testosterone associates with features of muscle wasting in men with CKD.

METHODS

This was a cross-sectional observational study of 267 men with CKD stages 2-4 (mean ± standard deviation age 67 ± 13 years, estimated glomerular filtration rate 42.9 [interquartile range 30.2-56.7] mL/min/1.73 m²) with measurements of endogenous testosterone and surrogates of PEW such as albumin, prealbumin, high-sensitivity C-reactive protein (CRP) and normalized protein nitrogen appearance (nPNA). Fat-free mass was estimated by bioelectrical impedance vector analysis (BIVA) and muscle strength by handgrip dynamometry.

RESULTS

Across decreasing thirds of testosterone distribution, patients were incrementally older and CRP levels rose significantly. Prealbumin, hemoglobin, nPNA, handgrip strength, and BIVA estimated surrogates of muscle mass and nutritional status (fat-free mass, body cell mass, and phase angle) were progressively reduced (P < .05 for all). In multivariate regression analyses including age, renal function, and other important confounders, testosterone significantly and independently contributed to explain the variances of handgrip strength and fat-free mass (P < .05 for all).

CONCLUSIONS

Endogenous testosterone independently associates with muscle strength and fat-free mass in men with moderate CKD. It is plausible that the reduction in testosterone levels that accompanies CKD may further contribute to the procatabolic environment leading to muscle wasting.

Musculoskeletal phenotype through the life course: the role of nutrition

This review considers the definition of a healthy bone phenotype through the life course and the modulating effects of muscle function and nutrition. In particular, it will emphasise that optimal bone strength (and how that is regulated) is more important than simple measures of bone mass. The forces imposed on bone by muscle loading are the primary determinants of musculoskeletal health. Any factor that changes muscle loading on the bone, or the response of bone to loading results in alterations of bone strength. Advances in technology have enhanced the understanding of a healthy bone phenotype in different skeletal compartments. Multiple components of muscle strength can also be quantified. The critical evaluation of emerging technologies for assessment of bone and muscle phenotype is vital. Populations with low and moderate/high daily Ca intakes and/or different vitamin D status illustrate the importance of nutrition in determining musculoskeletal phenotype. Changes in mass and architecture maintain strength despite low Ca intake or vitamin D status. There is a complex interaction between body fat and bone which, in addition to protein intake, is emerging as a key area of research. Muscle and bone should be considered as an integrative unit; the role of body fat requires definition. There remains a lack of longitudinal evidence to understand how nutrition and lifestyle define musculoskeletal health. In conclusion, a life-course approach is required to understand the definition of healthy skeletal phenotype in different populations and at different stages of life.

Microarchitectural changes in the aging skeleton

The age-related reduction in bone mass is disproportionally related to skeletal weakening, suggesting that microarchitectural changes are also important determinants of bone quality. The study of cortical and trabecular microstructure, which for many years was mainly based on two-dimensional histologic and scanning electron microscopy imaging, gained a tremendous momentum in the last decade and a half, due to the introduction of microcomputed tomography (μCT). This technology provides highly accurate qualitative and quantitative analyses based on three-dimensional images at micrometer resolution, which combined with finite elemental analysis predicts the biomechanical implications of microstructural changes. Global μCT analyses of trabecular bone have repeatedly suggested that the main age-related change in this compartment is a decrease in trabecular number with unaltered, or even increased, trabecular thickness. However, we show here that this may result from a bias whereby thick trabeculae near the cortex and the early clearance of thin struts mask authentic trabecular thinning. The main cortical age-related change is increased porosity due to negatively balanced osteonal remodeling and expansion of Haversian canals, which occasionally merge with endosteal and periosteal resorption bays, thus leading to rapid cortical thinning and cortical weakening. The recent emergence of CT systems with submicrometer resolution provides novel information on the age-related decrease in osteocyte lacunar density and related micropetrosis, the result of lacunar hypermineralization. Last but not least, the use of the submicrometer CT systems confirmed the occurrence of microcracks in the skeletal mineralized matrix and vastly advanced their morphologic characterization and mode of initiation and propagation.

The ESR1 (6q25) locus is associated with calcaneal ultrasound parameters and radial volumetric bone mineral density in European men

Purpose

Genome-wide association studies (GWAS) have identified 6q25, which incorporates the oestrogen receptor α gene (ESR1), as a quantitative trait locus for areal bone mineral density (BMD_a) of the hip and lumbar spine. The aim of this study was to determine the influence of this locus on other bone health outcomes; calcaneal ultrasound (QUS) parameters, radial peripheral quantitative computed tomography (pQCT) parameters and markers of bone turnover in a population sample of European men.

Methods

Eight single nucleotide polymorphisms (SNP) in the 6q25 locus were genotyped in men aged 40–79 years from 7 European countries, participating in the European Male Ageing Study (EMAS). The associations between SNPs and measured bone parameters were tested under an additive genetic model adjusting for centre using linear regression.

Results

2468 men, mean (SD) aged 59.9 (11.1) years had QUS measurements performed and bone turnover marker levels measured. A subset of 628 men had DXA and pQCT measurements. Multiple independent SNPs showed significant associations with BMD using all three measurement techniques. Most notably, rs1999805 was associated with a 0.10 SD (95%CI 0.05, 0.16; p = 0.0001) lower estimated BMD at the calcaneus, a 0.14 SD (95%CI 0.05, 0.24; p = 0.004) lower total hip BMD_a, a 0.12 SD (95%CI 0.02, 0.23; p = 0.026) lower lumbar spine BMD_a and a 0.18 SD (95%CI 0.06, 0.29; p = 0.003) lower trabecular BMD at the distal radius for each copy of the minor allele. There was no association with serum levels of bone turnover markers and a single SNP which was associated with cortical density was also associated with cortical BMC and thickness.

Conclusions

Our data replicate previous associations found between SNPs in the 6q25 locus and BMD_a at the hip and extend these data to include associations with calcaneal ultrasound parameters and radial volumetric BMD.

Sex and gender considerations in male patients with osteoporosis

BACKGROUND

Osteoporosis remains underrecognized and undertreated in both men and women, but men who sustain fragility fractures experience greater morbidity and mortality. While men exhibit advanced comorbidity at the time of hip fracture presentation, there are distinct sex- and gender-specific factors related to the pathophysiology and treatment of osteoporosis that further influence morbidity and mortality.

QUESTIONS/PURPOSES

With a selective review of the literature, we evaluated sex- and gender-based differences contributing to increased morbidity and mortality in men with osteoporosis. WHERE ARE WE NOW?: Sex-specific differences in bone biology and morphology may affect the pathophysiology of osteoporosis, choice of pharmacotherapy, and surgical implant selection. Additionally, estrogen metabolism may play a key role in both fracture prevention and healing. Gender-based differences in recommendations for screening and prevention between men and women may influence the severity at which osteoporosis is recognized. Primary, secondary, and tertiary prevention efforts in men lag behind those of women. This may be due to a lack of consensus regarding screening guidelines for osteoporosis in men but may be attributed to lack of awareness in the physician and patient about osteoporosis and its potentially debilitating consequences. WHERE DO WE NEED TO GO?: These disparities are a call to action for healthcare providers to raise awareness for early prevention and treatment of this potentially debilitating disease, particularly in men. HOW DO WE GET THERE?: Continued prospective research on the differences between men and women diagnosed with osteoporosis is needed, as well as sex-specific stratification of data in all studies on osteoporosis.