Relationship of serum sex steroid levels and bone turnover markers with bone mineral density in men and women: a key role for bioavailable estrogen

Bone density in chronic schizophrenia with long-term antipsychotic treatment: preliminary study

OBJECTIVE

Decreased bone mineral density has been found in the chronic schizophrenic patients who have been given a long-term administration of antipsychotics. Hyperprolactinemia from the antipsychotics and the negative symptom of schizophrenia were considered as the causes for this finding. In this study, the effect of hyperprolactinemia and the negative symptom of schizophrenia on bone mineral density was investigated on male schizophrenic patients.

METHODS

The cross-sectional study was carried out with the subjects of 45 male schizophrenic patients who have undertaken the monotherapy with risperidone, olanzapine and clozapine for at least one year. The demographic factors, clinical symtoms, bone mineral density and hematological test were examined for all the subjects.

RESULTS

No significant relationship was found between hyperprolactinemia and the decreased bone mineral density in the subjects. The negative schizophrenia symptom of the subjects showed a significant effect on the decreased bone mineral density.

CONCLUSION

The decreased bone mineral density finding in the male schizophrenic patients may be caused by the negative schizophrenia symptom rather than the hyperprolactinemia due to the antipsychotics. Additional studies are further required regarding other factors that may affect the decreased bone mineral density such as activity, calcium intake and exposure to sunlight.

Sex steroid hormones in older men: longitudinal associations with 4.5-year change in hip bone mineral density--the osteoporotic fractures in men study

CONTEXT

There is limited information on the association between sex hormones and bone loss in older men.

OBJECTIVE

Our objective was to determine the longitudinal association between sex steroid hormones and bone mineral density (BMD).

DESIGN AND SETTING

We conducted a prospective study of 5995 men aged at least 65 yr old at six U.S. clinical centers.

PARTICIPANTS

Sex steroid hormones were measured in a random sample of 1602 men. After exclusions, 1238 men were included in cross-sectional analyses and 969 in longitudinal analyses. Baseline sex hormones were measured using liquid chromatography-mass spectrometry. Bioavailable (Bio) estradiol (BioE2) and testosterone (BioT) were calculated from mass action equations. SHBG was measured using chemiluminescent substrate.

MAIN OUTCOME MEASURES

BMD of the total hip, measured at baseline and once or twice afterward over 4.6 yr of follow-up, was evaluated.

RESULTS

The annualized percent change in hip BMD increased with decreasing BioE2 (P trend = 0.03). Men with the lowest BioE2 (<39.7 pmol/liter) compared with the highest BioE2 (> or =66.0 pmol/liter) experienced 38% faster rate of BMD loss (P < 0.05). There was no association between BioT and hip BMD loss. Men with lowest BioE2, lowest BioT, and highest SHBG experienced a 3-fold faster rate of BMD loss compared with men with higher levels (P = 0.02). A threshold effect of SHBG was observed; the rate of hip BMD loss increased in men with SHBG of 49-60 nM.

CONCLUSIONS

Low BioE2 and high SHBG levels were associated with lower BMD and faster hip BMD loss. The combination of low BioE2, low BioT, and high SHBG was associated with significantly faster rates of BMD loss.

Correlates of trabecular and cortical volumetric bone mineral density at the femoral neck and lumbar spine: the osteoporotic fractures in men study (MrOS)

The objective of this cross-sectional analysis was to examine the correlates of trabecular and cortical volumetric bone mineral density (vBMD) in 3670 community-dwelling men, mean age 73.6 ± 5.9 years. vBMD was measured by quantitative computed tomography (QCT) and areal BMD by dual-energy X-ray absorptiometry (DXA). Demographic, historical, and lifestyle information was obtained by interview, and height, weight, and neuromuscular function were determined by examination. To express the strength of the associations, percent differences (95% confidence interval) were calculated from multivariable linear regression models using the formula 100 (β × unit/mean BMD). Units for continuous variables were chosen to approximate 1 standard deviation (SD). The multivariable linear regression models predicted 15%, 21%, and 20% of the overall variance in trabecular and cortical vBMD of the femoral neck and vBMD of the lumbar spine, respectively. Diabetes was associated with a 16.5% greater trabecular vBMD at the femoral neck and 11% at the lumbar spine but less than 2% for cortical vBMD. For femoral neck trabecular vBMD, the strongest negative correlates were past smoking (-9%), fracture history (-15%), kidney stones (-7%), corticosteroids (-11%), and insulin therapy (-26%). For cortical vBMD, the strongest negative correlate was use of thyroid medication (-2.8%). The strongest negative correlates for lumbar spine trabecular vBMD were fracture history (-5%), antiandrogen use (-19%), height (-8%), and thiazoliainedione use (-22%). Bioavailable estradiol and testosterone levels were positively related and sex hormone-binding globulin was negatively related to trabecular vBMD of the spine. There was no relationship between sex hormones and femoral neck trabecular vBMD. Our conclusion is that correlates of trabecular vBMD and cortical vBMD appear to differ in older men.

Physiology of bone loss

The physiology of bone loss in aging women and men is largely explained by the effects of gonadal sex steroid deficiency on the skeleton. In women, estrogen deficiency is the main cause of early rapid postmenopausal bone loss, whereas hyperparathyroidism and vitamin D deficiency are thought to explain age-related bone loss later in life. Surprisingly, estrogen deficiency also plays a dominant role in the physiology of bone loss in aging men. Many other factors contribute to bone loss in aging women and men, including defective bone formation by aging osteoblasts, impairment of the growth hormone/insulin-like growth factor axis, reduced peak bone mass, age-associated sarcopenia, leptin secreted by adipocytes, serotonin secreted by the intestine, and a long list of sporadic secondary causes. Further elucidation of the relative importance of each of these factors will lead to improved preventive and therapeutic approaches for osteoporosis.

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.

Bone turnover across the menopause transition : The role of gonadal inhibins

Accumulating evidence demonstrates increasing bone turnover and bone loss in women prior to menopause and decreases in serum estradiol levels. Increased follicle-stimulating hormone levels have been correlated with some of these peri-menopausal changes. However, decreases in gonadal inhibins of the transforming growth factor (TGF)-beta superfamily strongly correlate with increases in bone formation and resorption markers across the menopause transition and predict lumbar bone mass in peri-menopausal women, likely as a result of direct inhibin suppression of osteoblastogenesis and osteoclastogenesis. Inhibins bind specifically to cells during osteoblastogenesis and osteoclastogenesis. They can block bone morphogenetic protein (BMP)-stimulated osteoblast and osteoclast development as well as BMP-stimulated SMAD1 phosphorylation, likely via inhibin-beta-glycan sequestration of BMP Type II receptor (BMPRII). Interestingly, continuous in vivo exposure to inhibin A is anabolic and protective against gonadectomy-induced bone loss in mice, suggesting that inhibins contribute to the endocrine regulation of bone metabolism via a bimodal mechanism of action whereby cycling inhibin exposure suppresses bone turnover and continuous exposure to inhibins is anabolic.

Effects on lipoprotein particles of long-term dehydroepiandrosterone in elderly men and women and testosterone in elderly men

CONTEXT

Although age-related declines in dehydroepiandrosterone sulfate (DHEAS) and testosterone are associated with cardiovascular risk, it remains to be determined whether replacement of these hormones improves cardiovascular risk factors.

OBJECTIVE

This study sought to determine the effect of long-term replacement of dehydroepiandrosterone (DHEA) in elderly men and women and testosterone in elderly men on lipid and lipoprotein concentrations and particle sizes.

METHODS

A 2-yr randomized, placebo-controlled, double-blind study was conducted in 87 elderly men with low levels of DHEAS and bioavailable testosterone and 57 elderly women with low levels of DHEAS. Among elderly men, 29 received DHEA (75 mg/d), 27 received testosterone (5 mg/d), and 31 received placebo. Among the elderly women, 27 received DHEA (50 mg/d), and 30 received placebo. Baseline lipoprotein profiles in the elderly were compared to healthy younger participants. Low-density lipoprotein (LDL) and high-density lipoprotein (HDL) particle sizes and concentrations were quantified using nuclear magnetic resonance spectroscopy.

RESULTS

The elderly had higher concentrations of total cholesterol, triglycerides, LDL cholesterol, total LDL particles, and small, dense LDL particles than the young. In men, neither DHEA nor testosterone affected LDL or HDL particle concentrations. In women, DHEA reduced HDL cholesterol [median difference (95% confidence intervals), -5.0 (-8.0, -2.0) mg/dl; P = 0.002] and the number of large HDL particles [-1.0 (-1.8, -0.2) micromol/liter; P = 0.003].

CONCLUSIONS

Long-term DHEA and testosterone had no significant effect on plasma lipoproteins in elderly men, but elderly women showed a lowering of the large HDL particles that may have potential adverse clinical implications.

Pathogenesis of Osteoporosis

As for most multifactorial disorders, the pathogenesis of osteoporosis is complex, and a different set of mechanisms may be operative in any given individual. However, there are certain common causes of bone loss and increased fracture risk with aging in most people. These include genetic factors contributing to the acquisition of peak bone mass, illnesses affecting skeletal growth and development, sex steroid deficiency following the menopause in women and with aging in men, and intrinsic, age-related changes in bone metabolism. Superimposed on these factors are specific secondary causes of bone loss, such as corticosteroid use or other illnesses affecting bone metabolism that may contribute to fracture risk in individuals exposed to these factors. The past decade has witnessed tremendous advances in our understanding of each of these various causes of bone loss, leading to the development of novel, mechanism-based therapeutic approaches to prevent and treat this important public health disorder.

Loading-related regulation of gene expression in bone in the contexts of estrogen deficiency, lack of estrogen receptor alpha and disuse

Loading-related changes in gene expression in resident cells in the tibia of female mice in the contexts of normality (WT), estrogen deficiency (WT-OVX), absence of estrogen receptor alpha (ERalpha(-/-)) and disuse due to sciatic neurectomy (WT-SN) were established by microarray. Total RNA was extracted from loaded and contra-lateral non-loaded tibiae at selected time points after a single, short period of dynamic loading sufficient to engender an osteogenic response. There were marked changes in the expression of many genes according to context as well as in response to loading within those contexts. In WT mice at 3, 8, 12 and 24 h after loading the expression of 642, 341, 171 and 24 genes, respectively, were differentially regulated compared with contra-lateral bones which were not loaded. Only a few of the genes differentially regulated by loading in the tibiae of WT mice have recognized roles in bone metabolism or have been linked previously to osteogenesis (Opn, Sost, Esr1, Tgfb1, Lrp1, Ostn, Timp, Mmp, Ctgf, Postn and Irs1, BMP and DLX5). The canonical pathways showing the greatest loading-related regulation were those involving pyruvate metabolism, mitochondrial dysfunction, calcium-induced apoptosis, glycolysis/gluconeogenesis, aryl hydrocarbon receptor and oxidative phosphorylation. In the tibiae from WT-OVX, ERalpha(-/-) and WT-SN mice, 440, 439 and 987 genes respectively were differentially regulated by context alone compared to WT. The early response to loading in tibiae of WT-OVX mice involved differential regulation compared to their contra-lateral non-loaded pair of fewer genes than in WT, more down-regulation than up-regulation and a later response. This was shared by WT-SN. In tibiae of ERalpha(-/-) mice, the number of genes differentially regulated by loading was markedly reduced at all time points. These data indicate that in resident bone cells, both basal and loading-related gene expression is substantially modified by context. Many of the genes differentially regulated by the earliest loading-related response were primarily involved in energy metabolism and were not specific to bone.

A randomized controlled trial of add-back estrogen or placebo on cognition in men with prostate cancer receiving an antiandrogen and a gonadotropin-releasing hormone analog

The effects of testosterone (T) and estradiol (E(2)) on cognition in men are confounded in extant studies. This randomized, placebo-controlled trial was undertaken to investigate the possible effects of E(2) on cognition in older men. Twenty-five men with prostate cancer (mean age: 71.0+/-8.8 years) who required combined androgen blockade treatment were enrolled. Performance on cognitive tests was evaluated at pre-treatment baseline and following 12 weeks of treatment with a gonadotropin-releasing hormone analog and the nonsteroidal antiandrogen bicalutamide to determine whether specific cognitive functions would decline when the production of both T and E(2) were suppressed. In the second phase of the study, either micronized E(2) 1mg/day or an oral daily placebo was randomly added to the combined androgen blockade for an additional 12 weeks to determine whether E(2) would enhance performance in specific cognitive domains (verbal memory, spatial ability, visuomotor abilities and working memory). Compared to pretreatment, no differences in scores occurred on any cognitive test following 12 weeks of combined androgen blockade. In the add-back phase of the study (Visit 3), the placebo-treated men, but not the E(2)-treated men, exhibited a trend towards improvement in their scores on both the immediate (p=.075) and delayed recall (p=.095) portions of a verbal memory task compared to baseline. Moreover, at Visit 3, placebo-treated men performed significantly better than the E(2)-treated men on both the immediate (p=.020) and delayed recall (p=.016) portions of the verbal memory task. Thus, combined androgen blockade plus add-back E(2) failed to improve short- or long-term verbal memory performance in this sample of older men being treated for prostate cancer.

Update in male osteoporosis

CONTEXT

Osteoporosis in men is becoming an increasingly important public health problem. One in five men over the age of 50 yr will suffer an osteoporotic fracture during their lifetime, and men who sustain fractures have an increased mortality risk.

EVIDENCE ACQUISITION

Evidence was obtained by PubMed search and author's knowledge of the field.

EVIDENCE SYNTHESIS

Studies using computed quantitative tomography and high-resolution peripheral computed quantitative tomography have provided new insights into the bone structural changes with aging in men, including the somewhat surprising demonstration of significant, ongoing trabecular bone loss starting in young adult life. In addition, there are now data demonstrating that serum estradiol levels are important predictors of fracture risk in men and that there is a threshold estradiol level below which not only bone loss but also fracture risk increases markedly. Criteria for diagnosing and managing osteoporosis in men are also evolving, including the application of the fracture risk assessment tool to derive 10-yr fracture risks in men. Three bisphosphonates (alendronate, risedronate, and zolendronic acid) and teriparatide are currently U.S. Food and Drug Administration approved for the treatment of osteoporosis in men, with a number of new compounds, including a monoclonal antibody against receptor activator of nuclear factor-kappaB ligand, selective estrogen receptor modulators, and selective androgen receptor modulators in varying stages of development.

CONCLUSIONS

Despite significant advances, there remain a number of key unresolved issues regarding the pathogenesis and management of male osteoporosis, not the least of which is increasing public awareness of this important cause of morbidity and mortality in men.

Effects of aromatase inhibition on bone mineral density and bone turnover in older men with low testosterone levels

CONTEXT

Aging is associated with declining gonadal steroid production, low bone mineral density (BMD), and fragility fractures. The efficacy and safety of testosterone replacement in older men remains uncertain.

OBJECTIVE

The objective of the study was to assess the effects of aromatase inhibition on BMD in older men with low testosterone levels.

DESIGN AND SETTING

This was a 1-yr, double-blind, randomized, placebo-controlled trial that was conducted at a tertiary care academic center in Boston, MA.

PARTICIPANTS

Participants included 69 men aged 60+ yr with borderline or low testosterone levels and hypogonadal symptoms.

INTERVENTION

Intervention included 1 mg anastrozole daily or placebo.

MAIN OUTCOME MEASURES

Changes in gonadal steroid hormone levels, BMD, and bone turnover markers were measured.

RESULTS

Mean serum testosterone increased from 319 +/- 93 ng/dl at baseline to 524+/-139 ng/dl at month 3 (P < 0.0001) and declined slightly to 474 +/- 145 ng/dl by 1 yr. Estradiol levels decreased from 15 +/- 4 pg/ml at baseline to 12 +/- 4 pg/ml at month 3 and then remained stable (P < 0.0001). Posterior-anterior (PA) spine BMD decreased in the anastrozole group as compared with placebo (P = 0.0014). In the anastrozole group, PA spine BMD decreased from 1.121 +/- 0.141 g/cm(2) to 1.102 +/- 0.138 g/cm(2), whereas in the placebo group, PA spine BMD increased from 1.180 +/- 0.145 g/cm(2) to 1.189 +/- 0.146 g/cm(2). Qualitatively similar, but not statistically significant, changes occurred at the other sites. Bone turnover markers were not affected by anastrozole therapy.

CONCLUSIONS

In older men, aromatase inhibition increases testosterone levels, decreases estradiol levels, and appears to decrease BMD. Aromatase inhibition does not improve skeletal health in aging men with low or low normal testosterone levels.

Estrogens as regulators of bone health in men

Bone metabolism is influenced by sex steroids during growth and adulthood in both men and women. Although this influence is well described in women, the relative importance of androgens and estrogens in the regulation of the male skeleton remains uncertain. Even though estradiol has been considered the 'female hormone', levels of serum estradiol in elderly men are higher than those in postmenopausal women. Estradiol levels are more strongly associated with BMD, bone turnover and bone loss than testosterone levels are in adult men. Case reports of young men with estrogen resistance or aromatase deficiency also suggest a crucial role for estradiol in regulation of skeletal growth in men. Moreover, serum levels of both estrogens and androgens are inversely associated with the risk of fracture in aging men. A large, prospective, population-based study showed that levels of serum estradiol predict the risk of fracture, independently of serum testosterone. Evidence suggests that a threshold level of estradiol exists below which the male skeleton is impaired; rates of bone loss and fracture seem to be increased and bone maturation delayed in men with estradiol levels below this threshold. On the basis of these findings, we propose that not only androgens, but also estrogens, are important regulators of bone health in men.

Low body mass index and declining sex steroids explain most age-related bone loss in Brazilian men

SUMMARY

Osteoporosis in men is underestimated, but our data point to an increasing prevalence rate in those over 70 years old with body mass index (BMI) <25 kg/m(2), bioavailable testosterone <2.7 nmol/L, bioavailable estradiol <40 pmol/L, and high bone turnover, defined in this study as serum carboxyterminal cross-linked telopeptide of type I collagen (ICTP) >4.3 microg/L.

INTRODUCTION

The association of sex steroids and osteoporosis was evaluated in 104 men, aged 50-93 years old.

METHODS

Bone mineral density (BMD), bone turnover (ICTP), testosterone (T), and estradiol (E(2)) were measured; free and bioavailable hormones (free testosterone index [FTI], BioT, free estradiol index [FEI], and BioE(2)) were calculated from T, E(2), sex hormone-binding globulin (SHBG), and albumin. Nonparametric analysis and Poisson regression models were used.

RESULTS

Significant increases in SHBG and ICTP and decreases in femoral neck BMD, FTI, FEI, BioT, and BioE(2) were observed with each additional decade of age. Femoral neck BMD was inversely correlated with ICTP, and both were significantly associated with SHBG, FTI, BioT, FEI, and BioE. There was a direct and graded association between age and osteoporosis prevalence rate (OP PR; p = 0.028). Compared to participants less than 70 years old, the crude OP PR of those 80 years and older was 3.2 (95%CI = 1.4-7.3). Adjusting sequentially for BMI and bioavailable sex hormones attenuated the association between age and osteoporosis prevalence by 55% and 77%, respectively.

CONCLUSION

Our data support the view that low BMI and declining sex steroids explain most of the association between aging, increased bone turnover, and osteoporosis in men.

Circulating adiponectin represents a biomarker of the association between adiposity and bone mineral density

An association exists between adiposity, insulin resistance, and osteoporosis; however, the mechanism of this relationship remains enigmatic. We aimed to determine whether the insulin resistance index (HOMA-IR), serum adiponectin, or leptin levels are associated with bone mineral density (BMD). A cross-sectional, observational study was designed. Eighty-four postmenopausal ambulant women [52.5 (50.0-58.0) years; body mass index (BMI): 29.4 (25.9-33.8) kg/m(2)] referred for osteoporosis screening were enrolled. Anthropometric measures, fasting serum adiponectin and leptin levels, and the HOMA-IR were determined. The relationships between these variables and lumbar, hip, and forearm BMD measured by dual-energy X-ray absorptiometry (DXA) were analyzed. Considering all 84 participants, the HOMA-IR index was 1.82 (1.17-2.86), serum adiponectin was 13.25 (10.49-16.88) microg/ml, and serum leptin was 19.26 (14.94-24.90) ng/ml. BMI, waist circumference, and leptin positively correlated with hip and lumbar BMD, whereas adiponectin negatively correlated. Multivariate analysis confirmed an inverse relation between serum adiponectin level and femoral neck and lumbar BMD measurements. In total hip and forearm areas, there was no independent association of adipocytokines with BMD measurements. Instead, waist circumference was independently associated with BMD measurements. In conclusion, adiponectin may represent a biomarker in the relationship between visceral fat mass and BMD. However, this association is probably confounded by the specific body composition parameters (i.e., waist circumference, BMI) in postmenopausal women.

Alterations of T cell activation signalling and cytokine production by postmenopausal estrogen levels

Background

Immunosenescence is an age-associated disorder occurring primarily in T cell compartments, including altered subset composition, functions, and activation. In women, evidence implicates diminished estrogen in the postmenopausal period as a contributing factor to diminished T cell responsiveness. Since hypoestrogenism is present in postmenopausal women, our objective focused on whether T cell activation, defined as signalling molecule expressions and activation, and function, identified as IL-2 production, were affected by low estrogen.

Methods

Using Jurkat 6.1 T cells, consequences of 4 pg/ml (corresponding to postmenopausal levels) or 40 pg/ml (premenopausal levels) of estradiol (E₂) were analyzed on signalling proteins, CD3-zeta, JAK2, and JAK3, determined by Western immunoblotting. These consequences were correlated with corresponding gene expressions, quantified by real time-polymerase chain reaction. Tyrosine phosphorylation of CD3-zeta was defined by immunoprecipitation and western immunoblotting following activation by T cell receptor (TcR) cross-linking. CD3-zeta expression and modulation was also confirmed in T cells from pre- and postmenopausal women. To assess functional consequences, IL-2 production, induced by PMA and ionomycin, was determined using enzyme-linked immunosorbent spot assay (ELISpot).

Results

At 40 pg/ml E₂, the level of signalling protein CD3-zeta was elevated 1.57-fold, compared with cells exposed to 4 pg/ml E₂. The CD3-zeta proteins also exhibited altered levels of activation-induced phosphorylation in the presence of 40 pg/ml E₂ versus 4 pg/ml: 23 kD phosphorylated form increased 2.64-fold and the 21 kD form was elevated 2.95-fold. Examination of kinases associated with activation signalling also demonstrated that, in the presence of 40 pg/ml E₂, JAK2 protein expression was increased 1.64-fold (p < 0.001) and JAK3 enhanced 1.79-fold (p < 0.001) compared to 4 pg/ml. mRNA levels for CD3-zeta, JAK2, and JAK3 were significantly increased following exposure to 40 pg/ml E₂ (2.39, 2.01, and 2.21 fold, respectively) versus 4 pg/ml. These findings were confirmed in vivo, since T cells from postmenopausal women exhibited 7.2-fold diminished CD3-zeta expression, compared to pre-menopausal controls and this expression was elevated 3.8-fold by addition of 40 pg/ml E₂. Functionally, Jurkat cells exposed to 40 pg/ml E₂ and activated exhibited significantly elevated numbers of IL-2 producing colonies compared to 4 pg/ml (75.3 ± 2.2 versus 55.7 ± 2.1 colonies, p < 0.0001).

Conclusion

Jurkat T cells exposed to 4 pg/ml E₂ expressed significantly diminished activation signalling proteins, correlating with reduced IL-2 production. Lower signalling protein levels appear to result from decreased CD3-zeta, JAK2, and JAK3 gene expressions. These findings may provide a molecular basis for immunosenescence associated with the postmenopausal state.

Androgens and bone

Testosterone is the major gonadal sex steroid produced by the testes in men. Testosterone is also produced in smaller amounts by the ovaries in women. The adrenal glands produce the weaker androgens dehydroepiandrosterone, dehydroepiandrosterone sulfate, and androstenedione. These androgens collectively affect skeletal homeostasis throughout life in both men and women, particularly at puberty and during adult life. Because testosterone can be metabolized to estradiol by the aromatase enzyme, there has been controversy as to which gonadal sex steroid has the greater skeletal effect. The current evidence suggests that estradiol plays a greater role in maintenance of skeletal health than testosterone, but that androgens also have direct beneficial effects on bone. Supraphysiological levels of testosterone likely have similar effects on bone as lower levels via direct interaction with androgen receptors, as well as effects mediated by estrogen receptors after aromatization to estradiol. Whether high doses of synthetic, non-aromatizable androgens may, in fact, be detrimental to bone due to suppression of endogenous testosterone (and estrogen) levels is a potential concern that warrants further study.

Relation between serum testosterone, serum estradiol, sex hormone-binding globulin, and geometrical measures of adult male proximal femur strength

CONTEXT

Although previous studies have indicated associations between circulating testosterone (T) or estradiol (E2) concentrations and bone mineral density, the relationship between gonadal steroids and skeletal geometry is not well defined.

OBJECTIVE

Our objective was to uncover the relation between circulating T or E2 and proximal femur geometry in a diverse sample of men.

DESIGN

We used data on 808 men enrolled in the Boston Area Community Health/Bone Study. Serum concentrations of total and calculated free T and E2 were obtained via early-morning blood sampling. The geometry of the proximal femur at three sites (the narrow neck, intertrochanter, and shaft) was obtained using the Hip Structural Analysis technology. Analyses adjusted for subjects' age, height, total body lean mass and fat mass, and level of physical activity were performed.

SETTING

In-home interviews accompanied by subject visits to the General Clinical Research Center at Boston University School of Medicine were performed.

STUDY PARTICIPANTS

A randomly selected cohort of men living in Boston, MA (ages 30-79 yr) was included in the study.

INTERVENTIONS

These were not applicable.

MAIN OUTCOME MEASURES

Bone mineral density and bone outer diameter, cross-sectional area (measuring bone material), and section modulus (an index of bending strength) were calculated.

RESULTS

In age-adjusted models, E2 was positively associated with hip strength parameters, whereas T was not. Adjustment for age and other parameters resulted in substantial reductions in, but not complete elimination of, associations between E2 and hip strength parameters.

CONCLUSION

Circulating E2 is strongly associated with proximal femur strength, an association that is partially mediated by body composition.

Genetic variations in sex steroid-related genes as predictors of serum estrogen levels in men

CONTEXT

The risk of many conditions, including prostate cancer, breast cancer, and osteoporosis, is associated with serum levels of sex steroids.

OBJECTIVE

The aim of the study was to identify genetic variations in sex steroid-related genes that are associated with serum levels of estradiol (E2) and/or testosterone in men.

DESIGN

Genotyping of 604 single nucleotide polymorphisms in 50 sex steroid-related candidate genes was performed in the Gothenburg Osteoporosis and Obesity Determinants (GOOD) study (n = 1041 men; age, 18.9 +/- 0.6 yr). Replications of significant associations were performed in the Osteoporotic Fractures in Men (MrOS) Sweden study (n = 2568 men; age, 75.5 +/- 3.2 yr) and in the MrOS US study (n = 1922 men; age, 73.5 +/- 5.8 yr). Serum E2, testosterone, and estrone (E1) levels were analyzed using gas chromatography/mass spectrometry.

RESULTS

The screening in the GOOD cohort identified the single nucleotide polymorphism rs2470152 in intron 1 of the CYP19 gene, which codes for aromatase, responsible for the final step of the biosynthesis of E2 and E1, to be most significantly associated with serum E2 levels (P = 2 x 10(-6)). This association was confirmed both in the MrOS Sweden study (P = 9 x 10(-7)) and in the MrOS US study (P = 1 x 10(-4)). When analyzed in all subjects (n = 5531), rs2470152 was clearly associated with both E2 (P = 2 x 10(-14)) and E1 (P = 8 x 10(-19)) levels. In addition, this polymorphism was modestly associated with lumbar spine BMD (P < 0.01) and prevalent self-reported fractures (P < 0.05).

CONCLUSIONS

rs2470152 of the CYP19 gene is clearly associated with serum E2 and E1 levels in men.

Affective Disorders, Bone Metabolism, and Osteoporosis

The nature of the relationship between affective disorders, bone mineral density (BMD), and bone metabolism is unresolved, although there is growing evidence that many medications used to treat affective disorders are associated with low BMD or alterations in neuroendocrine systems that influence bone turnover. The objective of this review is to describe the current evidence regarding the association of unipolar and bipolar depression with BMD and indicators of bone metabolism, and to explore potential mediating and confounding influences of those relationships. The majority of studies of unipolar depression and BMD indicate that depressive symptoms are associated with low BMD. In contrast, evidence regarding the relationship between bipolar depression and BMD is inconsistent. There is limited but suggestive evidence to support an association between affective disorders and some markers of bone turnover. Many medications used to treat affective disorders have effects on physiologic systems that influence bone metabolism, and these conditions are also associated with a range of health behaviors that can influence osteoporosis risk. Future research should focus on disentangling the pathways linking psychotropic medications and their clinical indications with BMD and fracture risk.

Relationship of sex steroid hormones with bone mineral density (BMD) in a nationally representative sample of men

OBJECTIVE

Sex steroid hormones influence bone mineral density (BMD) in women, but are less well-studied in men. We evaluated the association of serum total and free sex steroid hormones and SHBG with osteopaenia in a nationally representative sample of men aged 20-90 years.

DESIGN

BMD and sex steroid hormones were measured among participants in NHANES III, a cross-sectional study of the US population.

POPULATION

A total of 1185 adult men in morning examination session of Phase I of NHANES III (1988-91).

MEASUREMENTS

Relation of oestradiol (E(2)), testosterone, and SHBG concentrations with BMD. Osteopaenia was defined as 1-2.5 SD below the mean for white men aged 20-29 years.

RESULTS

Men in the lowest quartile of free E(2) had 70% increased odds (OR = 1.69, 95% CI 0.95-2.98) of osteopaenia compared with men in the highest quartile. Men in the lowest quartile of free testosterone had nearly four times the odds of osteopaenia than those in the highest quartile (OR = 3.82, 95% CI 1.87-7.78). Lower concentrations of SHBG appeared protective against osteopaenia (P-trend = 0.01). Neither total testosterone nor total E(2) was associated with BMD, although men with clinically low E(2) (< 20 ng/l) had lower BMD (0.930 g/cm(2), 95% CI 0.88-0.98) than men with normal-range E(2) (1.024 g/cm(2), 95% CI 1.01-1.04; P = 0.004). Findings for free E(2) were most pronounced among elderly men, while the findings for free testosterone were most pronounced among younger men.

CONCLUSIONS

In this nationally representative study, men with lower free E(2), lower free testosterone, and higher SHBG concentrations in circulation were more likely to have low BMD.

The role of estrogen receptor-alpha gene TA polymorphism and aromatase gene TTTA polymorphism on peak bone mass attainment in males: is there an additive negative effect of certain allele combinations?

Idiopathic osteoporosis in males is influenced predominantly by low peak bone mass as a feature under a strong genetic control. Among a number of candidate genes, alpha-estrogen receptor (ERalpha) and CYP19 genes are of particular interest due to important role of estrogen in pathophysiology of osteoporosis. In the present study we examined the association of certain allelic combinations of ERalpha gene thymine-adenine (TA) polymorphism and aromatase gene TTTA polymorphism on bone mineral density (BMD) in young men. The study sample consisted of 92 unrelated healthy male volunteers, aged 21-35. In each subject, lumbar spine and proximal femur BMD, parameters of bone turnover and 25-OHD level were measured. Two ERalpha (TA)( n ) alleles, allele 19 and allele 21, were found to be associated with lower BMD. The presence of allele 19 was associated with significantly lower lumbar spine (P = 0.006) and trochanter (P = 0.02) BMD while the subjects positive for allele 21 had significantly lower lumbar spine (P = 0.04), trochanter (P = 0.02) and total hip (P = 0.03) BMD. Men with CYP19 (TTTA)(7-3)/ERalpha (TA)(19) allele combination had significantly lower lumbar spine BMD (P = 0.02) and those with CYP19 (TTTA)(7-3)/ERalpha (TA)(21) allele combination had significantly lower BMD for all three measurements, i.e. lumbar spine (P = 0.02), femoral neck (P = 0.02) and total hip (P = 0.008). These particular combinations of high-risk alleles were associated with lower median lumbar spine, femoral neck and total hip BMD than either of the allele alone suggesting that negative effect of two risk alleles on peak bone mass add up.

Sex-specific genetic architecture of human disease

Sexual dimorphism in anatomical, physiological and behavioural traits are characteristics of many vertebrate species. In humans, sexual dimorphism is also observed in the prevalence, course and severity of many common diseases, including cardiovascular diseases, autoimmune diseases and asthma. Although sex differences in the endocrine and immune systems probably contribute to these observations, recent studies suggest that sex-specific genetic architecture also influences human phenotypes, including reproductive, physiological and disease traits. It is likely that an underlying mechanism is differential gene regulation in males and females, particularly in sex steroid-responsive genes. Genetic studies that ignore sex-specific effects in their design and interpretation could fail to identify a significant proportion of the genes that contribute to risk for complex diseases.

Bones and Crohn's: estradiol deficiency in men with Crohn's disease is not associated with reduced bone mineral density

Background

Reduced bone mineral density (BMD) and osteoporosis are frequent in Crohn's disease (CD), but the underlying mechanisms are still not fully understood. Deficiency of sex steroids, especially estradiol (E2), is an established risk factor in postmenopausal osteoporosis.

Aim

To assess if hormonal deficiencies in male CD patients are frequent we investigated both, sex steroids, bone density and bone metabolism markers.

Methods

111 male CD patients underwent osteodensitometry (DXA) of the spine (L1–L4). Disease related data were recorded. Disease activity was estimated using Crohn's disease activity index (CDAI). Testosterone (T), dihydrotestosterone (DHT), estradiol (E2), sex hormone binding globulin (SHBG), Osteocalcin and carboxyterminal cross-linked telopeptids (ICTP) were measured in 111 patients and 99 age-matched controls.

Results

Patients had lower T, E2 and SHBG serum levels (p < 0.001) compared to age-matched controls. E2 deficiency was seen in 30 (27.0%) and T deficiency in 3 (2.7%) patients but only in 5 (5.1%) and 1 (1%) controls. Patients with E2 deficiency had significantly decreased T and DHT serum levels. Use of corticosteroids for 3 of 12 months was associated with lower E2 levels (p < 0.05). Patients with life-time steroids >10 g had lower BMD. 32 (28.8%) patients showed osteoporosis, 55 (49.5%) osteopenia and 24 (21.6%) had normal BMD. Patients with normal or decreased BMD showed no significant difference in their hormonal status. No correlation between markers of bone turnover and sex steroids could be found. ICTP was increased in CD patients (p < 0.001), and patients with osteoporosis had higher ICTP levels than those with normal BMD.

Conclusion

We found an altered hormonal status – i.e. E2 and, to a lesser extent T deficiency – in male CD patients but failed to show an association to bone density or markers of bone turnover. The role of E2 in the negative skeletal balance in males with CD, analogous to E2 deficiency in postmenopausal females, deserves further attention.

Comparison of sex steroid measurements in men by immunoassay versus mass spectroscopy and relationships with cortical and trabecular volumetric bone mineral density

In men, measurement of serum testosterone and estradiol levels with immunoassays correlated with mass spectroscopic measurements, and correlations of sex steroids with volumetric bone mineral density were similar.

INTRODUCTION

While immunoassays have been used extensively for measurement of serum testosterone (T) and estradiol (E(2)) levels, there is concern about their specificity, particularly at low E(2) levels as present in men.

METHODS

We compared T and E(2) measured by mass spectroscopy to levels measured by immunoassay in men (n = 313, age 22 to 91 years) and related these to volumetric bone mineral density (vBMD) at various skeletal sites.

RESULTS

Serum T and non-SHBG bound (or bioavailable) T levels by immunoassay correlated well with the corresponding mass spectroscopy measurements (R = 0.90 and 0.95, respectively, P < 0.001); the correlations for serum E(2) measured using the two techniques were less robust (R = 0.63 for total E(2) and 0.84 for bioavailable E(2), P < 0.001). Overall relationships between serum bioavailable T and E(2) levels with vBMD at various skeletal sites were similar for the immunoassay and mass spectroscopic measures.

CONCLUSIONS

Although E(2) levels with immunoassay correlate less well with the mass spectroscopic measurements than do the T measurements in men, our findings indicate that the fundamental relationships observed previously between vBMD and the sex steroids by immunoassay are also present with the mass spectroscopic measurements.

Abdominal aortic calcification, BMD, and bone microstructure: a population-based study

To better define the relationship between vascular calcification and bone mass/structure, we assessed abdominal aortic calcification (AAC), BMD, and bone microstructure in an age-stratified, random sample of 693 Rochester, MN, residents. Participants underwent QCT of the spine and hip and high-resolution pQCT (HRpQCT) of the radius to define volumetric BMD (vBMD) and microstructural parameters. AAC was quantified with the Agatston scoring method. In men, AAC correlated with lower vertebral trabecular and femoral neck vBMD (p < 0.001), but not after age or multivariable (age, body mass index, smoking status) adjustment. Separation into <50 and >or=50 yr showed this pattern only in the older men. BV/TV and Tb.Th inversely correlated with AAC in all men (p < 0.001), and Tb.Th remained significantly correlated after age adjustment (p < 0.05). Tb.N positively correlated with AAC in younger men (p < 0.001) but negatively correlated in older men (p < 0.001). The opposite was true with Tb.Sp (p = 0.01 and p < 0.001, respectively). Lower Tb.N and higher Tb.Sp correlated with AAC in older men even after multivariable adjustment. Among all women and postmenopausal women, AAC correlated with lower vertebral and femoral neck vBMD (p < 0.001) but not after adjustment. Lower BV/TV and Tb.Th correlated with AAC (p = 0.03 and p = 0.04, respectively) in women, but not after adjustment. Our findings support an age-dependent association between AAC and vBMD. We also found that AAC correlates with specific bone microstructural parameters in older men, suggesting a possible common pathogenesis for vascular calcification and deterioration in bone structure. However, sex-specific differences exist.

Higher muscle protein synthesis in women than men across the lifespan, and failure of androgen administration to amend age-related decrements

We investigated age and sex effects and determined whether androgen replacement in elderly individuals (> or = 60 yr) could augment protein synthesis. Thirty young men and 32 young women (18-31 yr) were studied once, whereas 87 elderly men were studied before and after 1 yr of treatment with 5 mg/day testosterone (T), 75 mg/day dehydroepiandrosterone (DHEA), or placebo (P); and 57 elderly women were studied before and after 1 yr of treatment with 50 mg/day DHEA or P. [(15)N]Phenylalanine and [(2)H(4)]tyrosine tracers were infused, with measurements in plasma and vastus lateralis muscle. Whole-body protein synthesis per fat-free mass and muscle protein fractional synthesis rate (FSR) were lower in elderly than in young individuals (P<0.001), not significantly affected by hormone treatments, and higher in women than in men (P<0.0001), with no sex x age interaction. In regression analyses, peak O2 consumption (VO2peak), resting energy expenditure (REE), and sex were independently associated with muscle FSR, as were VO2peak, REE, and interactions of sex with insulin-like growth factor-II and insulin for whole-body protein synthesis. Women maintain higher protein synthesis than men across the lifespan as rates decline in both sexes, and neither full replacement of DHEA (in elderly men and women) nor partial replacement of bioavailable T (in elderly men) is able to amend the age-related declines.

Estrogen and bone: insights from estrogen-resistant, aromatase-deficient, and normal men

Findings from estrogen-resistant and aromatase-deficient men have provided important insights into the role of estrogen in the male skeleton during growth. Importantly, as reported elsewhere in this issue, these data also suggested dose-response relationships between estrogen and bone turnover. In addition, studies in these unusual patients have stimulated research on defining the role of estrogen in regulating bone metabolism in normal adult and aging men, providing further insights into estrogen regulation of bone metabolism not only in men, but also in women.

Serum biomarker profile associated with high bone turnover and BMD in postmenopausal women

Early diagnosis of the onset of osteoporosis is key to the delivery of effective therapy. Biochemical markers of bone turnover provide a means of evaluating skeletal dynamics that complements static measurements of BMD by DXA. Conventional clinical measurements of bone turnover, primarily the estimation of collagen and its breakdown products in the blood or urine, lack both sensitivity and specificity as a reliable diagnostic tool. As a result, improved tests are needed to augment the use of BMD measurements as the principle diagnostic modality. In this study, the serum proteome of 58 postmenopausal women with high or low/normal bone turnover (training set) was analyzed by surface enhanced laser-desorption/ionization time-of-flight mass spectrometry, and a diagnostic fingerprint was identified using a variety of statistical and machine learning tools. The diagnostic fingerprint was validated in a separate distinct test set, consisting of serum samples from an additional 59 postmenopausal women obtained from the same Mayo cohort, with a gap of 2 yr. Specific protein peaks that discriminate between postmenopausal patients with high or low/normal bone turnover were identified and validated. Multiple supervised learning approaches were able to classify the level of bone turnover in the training set with 80% sensitivity and 100% specificity. In addition, the individual protein peaks were also significantly correlated with BMD measurements in these patients. Four of the major discriminatory peaks in the diagnostic profile were identified as fragments of interalpha-trypsin-inhibitor heavy chain H4 precursor (ITIH4), a plasma kallikrein-sensitive glycoprotein that is a component of the host response system. These data suggest that these serum protein fragments are the serum-borne reflection of the increased osteoclast activity, leading to the increased bone turnover that is associated with decreasing BMD and presumably an increased risk of fracture. In conjunction with the identification of the individual proteins, this protein fingerprint may provide a novel approach to evaluate high bone turnover states.

Testosterone for the aging male; current evidence and recommended practice

An international consensus document was recently published and provides guidance on the diagnosis, treatment and monitoring of late-onset hypogonadism (LOH) in men. The diagnosis of LOH requires biochemical and clinical components. Controversy in defining the clinical syndrome continues due to the high prevalence of hypogonadal symptoms in the aging male population and the non-specific nature of these symptoms. Further controversy surrounds setting a lower limit of normal testosterone, the limitations of the commonly available total testosterone result in assessing some patients and the unavailability of reliable measures of bioavailable or free testosterone for general clinical use. As with any clinical intervention testosterone treatment should be judged on a balance of risk versus benefit. The traditional benefits of testosterone on sexual function, mood, strength and quality of life remain the primary goals of treatment but possible beneficial effects on other parameters such as bone density, obesity, insulin resistance and angina are emerging and will be reviewed. Potential concerns regarding the effects of testosterone on prostate disease, aggression and polycythaemia will also be addressed. The options available for treatment have increased in recent years with the availability of a number of testosterone preparations which can reliably produce physiological serum concentrations.

Differences in trabecular bone of leptin-deficient ob/ob mice in response to biomechanical loading

OBJECTIVE

It is known that bone mineral density (BMD) and the strength of bone is predicted by body mass. Fat mass is a significant predictor of bone mineral density which correlates with body weight. This suggests that body fat regulates bone metabolism first by means of hormonal factors and second that the effects of muscle and loading are signaling factors in mechanotransduction. Leptin, a peptide hormone produced predominantly by white fat cells, is one of these hormonal factors. The aim of this study was to investigate and measure by micro-CT the different effects of weight-bearing on trabecular bone formation in mice without the stimulation of leptin.

RESULTS

Animals with an ad-libitum-diet (Group A) were found to increase body weight significantly at the age of six weeks in comparison with lean mice (Group B). From this point on, the difference increased constantly. At the age of twenty weeks the obese mice were almost twice as heavy as the lean mice. Significant statistical differences are shown between the two groups for body weight and bone mineral density. Examination of trabecular bone (BV/TV, trabecular number (Tb.N.), trabecular thickness (Tb.Th.)) revealed that the only statistically significant difference between the two groups was the Tb.N. for the proximal femur. High weight-bearing insignificantly improved all trabecular bone parameters in the obese mice. Compared with the control-diet Group B, the BV/TV and Tb.N. were slightly higher in the controlled-diet Group A, but not the Tb.Th.. However, correlation was found between Tb.N. and BMD on the one hand and body weight on the other hand.

CONCLUSION

biomechanical loading led to decreased bone mineral density by a decrease in the number of trabeculae. Trabecular thickness was not increased by biomechanical loading in growing mice. Decreased body weight in leptin-deficient mice protects against bone loss. This finding is consistent with the principle of light-weight construction of bone. Differences in cortical and trabecular bone will be examined in later studies. It is not possible to conclude that these results also apply to human beings.

Osteoporosis in men

With the aging of the population, there is a growing recognition that osteoporosis and fractures in men are a significant public health problem, and both hip and vertebral fractures are associated with increased morbidity and mortality in men. Osteoporosis in men is a heterogeneous clinical entity: whereas most men experience bone loss with aging, some men develop osteoporosis at a relatively young age, often for unexplained reasons (idiopathic osteoporosis). Declining sex steroid levels and other hormonal changes likely contribute to age-related bone loss, as do impairments in osteoblast number and/or activity. Secondary causes of osteoporosis also play a significant role in pathogenesis. Although there is ongoing controversy regarding whether osteoporosis in men should be diagnosed based on female- or male-specific reference ranges (because some evidence indicates that the risk of fracture is similar in women and men for a given level of bone mineral density), a diagnosis of osteoporosis in men is generally made based on male-specific reference ranges. Treatment consists both of nonpharmacological (lifestyle factors, calcium and vitamin D supplementation) and pharmacological (most commonly bisphosphonates or PTH) approaches, with efficacy similar to that seen in women. Increasing awareness of osteoporosis in men among physicians and the lay public is critical for the prevention of fractures in our aging male population.

Correlations between serum testosterone, estradiol, and sex hormone-binding globulin and bone mineral density in a diverse sample of men

CONTEXT

The relationship between hormones and bone mineral density (BMD) in men has received considerable attention. However, most studies have been conducted in homogenous populations, and it is not known whether differences in hormones impact racial and ethnic differences in BMD.

OBJECTIVE

Our objective was to examine associations of testosterone, estradiol, and sex hormone-binding globulin (SHBG) with BMD in a racially and ethnically diverse population.

DESIGN

This was a population-based, observational survey.

PARTICIPANTS

A total of 976 Black, Hispanic, and white randomly selected men ages 30-79 yr from the Boston Area Community Health/Bone Survey were included.

OUTCOME

BMD at the hip, wrist, and spine were calculated.

RESULTS

The mean age of the sample was 46.7 +/- 12.4 yr. BMD levels were highest in black men, followed by Hispanic and then white men. Associations between hormones and BMD were consistent across racial and ethnic groups. Total and free testosterone was not correlated with BMD in age- or multivariate-adjusted models. SHBG was inversely correlated with total hip and ultradistal radius BMD after age adjustment, but not with multivariate adjustment for age, lean mass, fat mass, physical activity, self-rated health, and smoking. Total and free estradiol levels were positively and significantly correlated with femoral neck and total hip BMD, even with multivariate adjustment (partial correlations ranged between 0.11 and 0.16). However, estradiol levels failed to account for racial and ethnic differences in hip BMD.

CONCLUSIONS

In our diverse population, neither serum total nor free testosterone levels were associated with BMD. Correlations between BMD and estradiol were significant but did not appear to account for any of the observed racial and ethnic differences in BMD. These findings suggest that differences in hormone levels are not a major contributor to the observed differences in BMD between Black, Hispanic, and white men.

Serum concentrations of estradiol and free T4 are inversely correlated with sperm DNA damage in men from an infertility clinic

Sperm DNA damage adversely affects male fertility and contributes to poorer embryo development and lower pregnancy rates. Endogenous hormones are critical to spermatogenesis and maintenance of male reproductive function and likely play an important role in human sperm DNA integrity, but this relationship is not fully understood. The present study measured serum hormone levels and sperm DNA damage with the neutral comet assay in 362 male partners of infertile couples. When sperm concentration and other potential confounding variables were included in multiple linear regression, serum estradiol and free T(4) levels were inversely associated with sperm DNA damage. Among other statistically significant associations that were observed, an interquartile range (IQR) increase in estradiol was associated with a 6.3% decline (95% confidence intervals: -9.7%, -2.9%) in comet extent and a 16.2% (-22.4%, -9.2%) decline in the percentage of DNA in the comet tail (Tail%), whereas an IQR increase in free T(4) was associated with a 24.4% (-31.5%, -17.4%) decline in Tail%. Likewise, in multiple logistic regression, men in the highest estradiol quartile had an 81% reduced risk of having a comet extent value in the highest quartile compared with men in the lowest estradiol quartile. Men in the highest free T(4) quartile had 92% decreased odds of being categorized in the highest Tail% quartile compared with men in the lowest free T(4) quartile. These results suggest that estradiol and free T(4) may have a protective effect against sperm DNA damage, but future mechanistic and epidemiologic studies are needed to confirm these findings.

A population-based assessment of rates of bone loss at multiple skeletal sites: evidence for substantial trabecular bone loss in young adult women and men

Using QCT, we made a longitudinal, population-based assessment of rates of bone loss over life at the distal radius, distal tibia, and lumbar spine. Cortical bone loss began in perimenopause in women and later in life in men. In contrast, trabecular bone loss began in young adulthood in both sexes.

INTRODUCTION

Although conventional wisdom holds that bone loss begins at menopause in women and later in life in men, this has not been examined longitudinally in population-based studies using precise technology capable of distinguishing cortical and trabecular bone.

MATERIALS AND METHODS

In an age- and sex-stratified population sample (n = 553), we measured volumetric BMD (vBMD) of trabecular and cortical bone by QCT annually for up to 3 yr at the distal radius (DR) and distal tibia (DT) (n = 552) and trabecular vBMD at baseline and 3 yr at the lumbar spine (LS) (n = 474).

RESULTS

Substantial cortical bone loss began in middle life in women but began mainly after age 75 in men. In contrast, substantial trabecular bone loss began in young adult women and men at all three skeletal sites and continued throughout life with acceleration during perimenopause in women. Women experienced 37% and men experienced 42% of their total lifetime trabecular bone loss before age 50 compared with 6% and 15%, respectively, for cortical bone. Median rates of change in trabecular bone (%/yr) were -0.40, -0.24, and -1.61 in young adult women and -0.38, -0.40, and -0.84 in young adult men at the DR, DT, and LS, respectively (all p < 0.001). The early trabecular bone loss did not consistently correlate with putative causal factors, except for a trend with IGF-related variables at DT in women. However, in postmenopausal women and, to a lesser extent, in older men, higher rates of cortical and trabecular bone loss were associated with lower levels of biologically-active sex steroids and with higher levels of follicle-stimulating hormone and bone turnover markers.

CONCLUSIONS

The late onset of cortical bone loss is temporally associated with sex steroid deficiency. However, the early-onset, substantial trabecular bone loss in both sexes during sex steroid sufficiency is unexplained and indicates that current paradigms on the pathogenesis of osteoporosis are incomplete.

Depression and osteoporosis: epidemiology and potential mediating pathways

INTRODUCTION

There have been numerous studies examining the association between depression and bone mineral density (BMD), but the underlying nature of this relationship remains unclear. Independent of this association, there is a growing body of evidence that depression impacts the risk for fracture in older adults. This article reviews the current epidemiological evidence regarding comorbidity of depression, low bone mineral density, and fracture.

METHODS

A review of the literature on depression, depressive symptoms, low BMD, osteoporosis, and fracture using electronic databases.

RESULTS

We reviewed 20 studies of the association between depression and BMD and five reports of the relationship between depression and fractures. Potential mediating mechanisms (both physiological and behavioral) are discussed, as well as potential confounding influences (e.g., medication use).

CONCLUSIONS

Most studies support the finding that depression is associated with increased risk for both low BMD and fractures, but variation in study design, sample composition, and exposure measurement make comparisons across studies difficult. Researchers should be aware of potential confounders, such as medication use, that may influence results. Future research should focus on identifying mediating pathways and targets for intervention in the relationships between depression, low BMD, and fracture.

Osteoporosis in men: its pathophysiology and the role of teriparatide in its treatment

As the population ages, the burden of osteoporosis in men is expected to rise. Implementation of preventive measures such as falls prevention strategies, exercise and adequate calcium and vitamin D intake is recommended. However, when the diagnosis of osteoporosis is made, effective treatments need to be initiated to prevent fractures. As opposed to postmenopausal women, reduced bone formation is the predominant mechanism of age-related bone loss in men, making anabolic agents a logical treatment option for men with osteoporosis. Teriparatide is the only anabolic agent currently approved for treatment of osteoporosis in men. This paper summarizes the mechanism of action of teriparatide, as well as its tolerability and safety. Furthermore, the evidence supporting the efficacy of teriparatide treatment in men with osteoporosis is reviewed and its current role in the management of osteoporosis in men is discussed.

Bone density in women with prolactinoma treated with dopamine agonists

OBJECTIVES

(1) to evaluate bone density in women with prolactinoma treated with dopamine agonists and healthy controls, using dual energy x-ray absorptiometry (DXA), (2) to classify the results according to the current International Society for Clinical Densitometry (ISCD) criteria, and (3) to correlate bone density with lean and fat masses, biochemical data and clinical aspects of prolactinomas.

MATERIALS AND METHODS

A cross-sectional study was performed in two University referral centers. Forty-five premenopausal women with prolactinoma were submitted to DXA and blood analysis (prolactin, estradiol, testosterone, SHBG, calcium, phosphorus, PTH, C-telopeptides of type 1 collagen, and osteocalcin) by the time of their clinical evaluation. They were compared with 25 control women of similar age and body mass index distribution.

RESULTS

Women with prolactinoma had lower lumbar spine Z-score than controls. Femoral neck, trochanter, and total proximal femur Z-scores were similar in patients and controls. Twenty-two percent of the patients had Z-scores below the expected age range vs. 4% in the control group. Lumbar spine, femoral neck, and total proximal femur Z-scores were mainly correlated with the amenorrhea duration. The trochanter Z-score was associated with the gynoid lean/fat mass ratio.

CONCLUSIONS

Based on the current ISCD criteria, bone density evaluation in women with prolactinoma reveals bone loss, especially of trabecular type. Bone density in these patients was particularly associated with the duration of amenorrhea, which reinforces the importance of the adequate disease control in women with prolactinoma in order to avoid complications of this disease.

Toremifene increases bone mineral density in men receiving androgen deprivation therapy for prostate cancer: interim analysis of a multicenter phase 3 clinical study

PURPOSE

We evaluated the effects of toremifene on bone mineral density, a surrogate for fracture risk, in men receiving androgen deprivation therapy for prostate cancer.

MATERIALS AND METHODS

In an ongoing, multicenter, phase 3 fracture prevention study 1,392 men 50 years or older with prostate cancer receiving androgen deprivation therapy were randomized to 80 mg toremifene per day or placebo. Bone mineral density of the lumbar spine, total hip and femoral neck was assessed using dual energy x-ray absorptiometry. In this planned interim analysis of the first 197 subjects we compared bone mineral density changes from baseline to month 12 between the placebo and toremifene groups.

RESULTS

Compared with the placebo group men in the toremifene group had significant increases in bone mineral density at each evaluated skeletal site. Lumbar spine bone mineral density decreased 0.7% in the placebo group and increased 1.6% in the toremifene group (between group comparison p <0.001). Total hip bone mineral density decreased 1.3% in the placebo group and increased 0.7% in the toremifene group (p = 0.001). Femoral neck bone mineral density decreased 1.3% in the placebo group and increased 0.2% in the toremifene group (p = 0.009). Between group differences in the change in bone mineral density from baseline to month 12 were 2.3%, 2.0% and 1.5% for the lumbar spine, total hip and femoral neck, respectively.

CONCLUSIONS

Toremifene significantly increased hip and spine bone mineral density in men receiving androgen deprivation therapy for prostate cancer. The effect of toremifene on the fracture risk is being assessed in the ongoing randomized, controlled trial.

Androgen deprivation therapy for prostate cancer: new concepts and concerns

PURPOSE OF REVIEW

The aim of this review is to summarize new concepts and concerns regarding treatment-related osteoporosis, diabetes, and cardiovascular disease in men receiving androgen deprivation therapy for prostate cancer.

RECENT FINDINGS

Gonadotropin-releasing hormone agonists increase bone turnover, decrease bone mineral density, and increase fracture risk. Bisphosphonates, selective and estrogen receptor modulators significantly increase bone mineral density during androgen deprivation therapy. Ongoing randomized controlled trials will assess efficacy of denosumab, toremifene, and zoledronic acid to prevent fractures in this setting. Gonadotropin-releasing hormone agonists also increase fat mass, decrease insulin sensitivity, and increase serum lipoproteins. In contrast to the classical metabolic syndrome, however, the phenotype of men during androgen deprivation therapy is characterized by increased high-density lipoprotein cholesterol and preferential accumulation of subcutaneous fat. Gonadotropin-releasing hormone agonists are associated with greater risk of incident diabetes and cardiovascular disease in men with prostate cancer.

SUMMARY

Androgen therapy increases risk of fractures, diabetes mellitus, and cardiovascular disease in men with prostate cancer. Current and planned studies will evaluate strategies to prevent these treatment-related adverse effects.

Bone turnover in elderly men: relationships to change in bone mineral density

Background

It is not clear whether bone turnover markers can be used to make inference regarding changes in bone mineral density (BMD) in untreated healthy elderly men. The present study was designed to address three specific questions: (i) is there a relationship between bone turnover markers and femoral neck BMD within an individual; (ii) is there a relationship between baseline measurements of bone turnover markers and subsequent change in BMD; and (iii) is there a relationship between changes in bone turnover markers and changes in femoral neck BMD?

Methods

The present study was part of the on-going Dubbo Osteoporosis Epidemiology Study, which was designed as a prospective investigation. Men who had had at least 3 sequential visits with serum samples available during follow-up were selected from the study population. Serum C-terminal telopeptide of type I collagen (sICTP), N-terminal propeptide of type I collagen (sPINP) and femoral neck BMD were measured by competitive radioimmunoassays. Femoral neck bone mineral density (BMD) was measured by a densitometer (GE Lunar Corp, Madison, WI). Various mixed-effects models were used to assess the association between the markers and changes in BMD.

Results

One hundred and one men aged 70 ± 4.1 years (mean ± SD) met the criteria of selection for analysis. On average, sPINP decreased by 0.7% per year (p = 0.026), sICTP increased by 1.7% per year (p = 0.0002), and femoral neck BMD decreased by 0.4% per year (p < 0.01). Within-subject analysis indicated that changes in BMD were significantly associated with changes in sPINP (p = 0.022), but not with changes in sICTP (p = 0.84). However, neither baseline sPINP (p = 0.50) nor baseline sICTP (p = 0.63) was associated with subsequent changes in BMD. Moreover, changes in BMD were not significantly associated with previous changes in sPINP (p = 0.13) or sICTP (p = 0.95).

Conclusion

These results suggest that in elderly men of Caucasian background, changes in sPINP were inversely related to changes in BMD within an individual. However, neither sPINP nor sICTP was sufficiently sensitive to predict the rate of change in BMD for a group of individuals or for an individual.

Treatment-related osteoporosis in men with prostate cancer

The intended therapeutic effect of gonadotropin-releasing hormone (GnRH) agonists is hypogonadism, a major cause of acquired osteoporosis in men. Consistent with this observation, GnRH agonists increase bone turnover and decrease bone mineral density, a surrogate for fracture risk. Large claims-based analyses and other retrospective studies provide compelling evidence that GnRH agonists increase risk of clinical fractures. Estrogens play a central role in homeostasis of the normal male skeleton, and estrogen deficiency rather than testosterone deficiency seems to be primarily responsible for the adverse skeletal effects of GnRH agonists. In randomized controlled trials, bisphosphonates (pamidronate and zoledronic acid) and selective estrogen receptor modulators (raloxifene and toremifene) increased bone mineral density in GnRH agonist-treated men. Two ongoing large randomized placebo-controlled studies will prospectively define fracture outcomes in men with prostate cancer and assess the efficacy of novel pharmacologic interventions (AMG162, toremifene) during GnRH agonist treatment.

Body mass index and colon cancer risk in Chinese people: menopause as an effect modifier

High body mass index (BMI) has consistently been associated with increased colon cancer risk in men, but not in women. It is hypothesised that menopause-related changes in oestrogen levels play a role in gender-specific risk patterns. Most studies have been conducted in Western countries, where high incidence rates are coupled with a high prevalence of obesity and relatively common use of hormone replacement therapy (HRT) in post-menopausal women. This study evaluated the correlation between body mass index (BMI) and colon cancer risk in a relatively lean population, comprising 931 cases and 1552 controls, in Shanghai, China, where HRT use was extremely rare among women, during 1990-1993. Among men, colon cancer risk significantly increased with increasing BMI (P-trend=0.005). Among women, the risk varied with age and menopause status in a similar pattern. Within each menopause stratum, however, the BMI-related risk was similar for those aged under 55 years and those aged 55 years and over, indicating a menopause rather than age effect. Among pre-menopausal women, the odds ratios (ORs) for subjects in the highest versus lowest quintile were 1.9 (95% CI 1.1-4.9) for those under 55 years of age, and 2.2 (95% CI 1.4-8.2) for those aged 55 years and over. Among post-menopausal women, the corresponding ORs were 0.6 (95% CI 0.5-0.91) and 0.7 (95% CI 0.5-0.95), respectively. Our findings suggest that BMI predicts colon cancer risk in both genders. Among women, however, the risk is modified by menopause status, possibly through altered endogenous oestrogen levels.

The relation of the XbaI and PvuII polymorphisms of the estrogen receptor gene and the CAG repeat polymorphism of the androgen receptor gene to peak bone mass and bone turnover rate among young healthy men

The genes coding for estrogen receptor-alpha (ER-alpha) and androgen receptors (AR) are potential candidates for the regulation of bone mass and turnover, which may contribute to both the achievement of peak bone mass and bone loss after completion of growth. The present study was aimed at elucidating the role of two restriction fragment lengths (XbaI and PvuII) polymorphisms of the ER gene and the CAG repeat polymorphism of the AR gene as determinants of peak bone mass in men; special attention was paid to the interaction between serum free estradiol (E2) levels and the XbaI and PvuII genotypes. A cross-sectional study, with data on lifestyle factors collected retrospectively, was performed in 234 young men, aged 18.3 to 20.6 years. Of the men, 184 were recruits of the Finnish Army and 50 were men of similar age who had postponed their military service for reasons not related to health. Bone mineral content (BMC), density (BMD) and scan area were measured in the lumbar spine and upper femur by dual-energy X-ray absorptiometry (DXA). The bone turnover rate was assessed by measuring serum type I procollagen aminoterminal propeptide (PINP) and tartrate-resistant acid phosphatase 5b (TRACP5b) as well as urinary excretion of type I collagen aminoterminal telopeptide (NTX). After adjusting for age, height, weight, exercise, smoking, calcium and alcohol intake, BMC, scan area and BMD at all measurement sites were similar for the different XbaI and PvuII genotypes of the ER and independent of the number of the CAG repeats of the AR gene. No association was found between free E2 levels and bone parameters among any genotype group of the XbaI and PvuII polymorphisms. Except for urinary NTX, which showed a tendency to higher values for the xx (P=0.08) and pp (P=0.10) genotypes of the ER, bone turnover markers were not related to the genotypes studied. Our study does not support the view that the XbaI and PvuII polymorphisms of the ER gene and the CAG polymorphism of the AR gene would have a substantial impact on the development of peak bone mass in young Finnish men.

Determinants of bone mineral density in Chinese men

Osteoporotic fractures are increasing among Asian populations in both genders, but the risk factors for low bone mineral density (BMD) in Asian men is unclear. To determine the hormonal and lifestyle risk factors for low BMD in Asian men, we studied 407 community-dwelling southern Chinese men aged 50 years and above. Medical history and lifestyle habits were obtained with a structured questionnaire. Dietary calcium and phytoestrogen intake were assessed by a semi-quantitative questionnaire. BMD at the spine and hip were measured by dual-energy X-ray absorptiometry (DXA). Fasting blood was analyzed for 25(OH)D, parathyroid hormone (PTH), total and bioavailable estradiol (bio-E) and testosterone (bio-T). The mean age of the cohort was 68.42+/-10.4 (50-96) years. In the linear regression model, weight, age, body mass index (BMI), bio-E, PTH, cigarette smoking and weight-bearing exercise were significant determinants of total hip BMD. Together they explained 55% of the total variance of hip BMD, with body weight being the most important determining factor. With age and weight adjustment, height, bio-T and flavonoid intake were identified as additional determinants of total hip BMD. Strategies to prevent bone loss and osteoporosis in Asian men should include lifestyle modification and maintenance of hormonal sufficiency.

Comparison of plasma endothelin levels between osteoporotic, osteopenic and normal subjects

Background

It has been demonstrated that endothelins (ET) have significant roles in bone remodeling, metabolism and physiopathology of several bone diseases. We aimed to investigate if there was any difference between the plasma ET levels of osteoporotic patients and normals.

Methods

86 patients (70 women and 16 men) with a mean age of 62.6 (ranges: 51–90) years were included in this study. Patients were divided into groups of osteoporosis, osteopenia and normal regarding reported T scores of DEXA evaluation according to the suggestions of World Health Organization. According to these criteria 19, 43 and 24 were normal, osteopenic and osteoporotic respectively. Then total plasma level of ET was measured in all patients with monoclonal antibody based sandwich immunoassay (EIA) method. One-way analysis of variance test was used to compare endothelin values between normals, osteopenics and osteoporotics.

Results

Endothelin total plasma level in patients was a mean of 98.36 ± 63.96, 100.92 ± 47.2 and 99.56 ± 56.6 pg/ml in osteoporotic, osteopenic and normal groups respectively. The difference between groups was not significant (p > 0.05).

Conclusion

No significant differences in plasma ET levels among three groups of study participants could be detected in this study.

Relationship of volumetric bone density and structural parameters at different skeletal sites to sex steroid levels in women

CONTEXT

Although estrogen clearly plays a central role in regulating bone mass in women, studies in men have suggested that there may be a threshold bioavailable (bio) estradiol (E2) level below which aging men begin to lose bone and that the threshold for estrogen deficiency in cortical bone may be considerably lower than that in trabecular bone. There are no data testing this in women.

OBJECTIVE

Our objective was to assess volumetric bone mineral density (vBMD) and bone geometry by quantitative computed tomography and relate these to circulating bio E2 and bio testosterone levels.

DESIGN

We studied a cross-sectional, age-stratified population sample of 235 women (age, 21-97 yr).

RESULTS

vBMD/structural parameters were not related to sex steroid levels in young premenopausal women (age, 20-39 yr) with a median bio E2 level of 17 pg/ml (63 pmol/liter). By contrast, bio E2 and bio testosterone levels were both significantly associated with trabecular and cortical vBMD and cortical area at multiple sites in late postmenopausal women (age > or = 60 yr) who had a median bio E2 level of 3 pg/ml (11 pmol/liter). Late premenopausal and early postmenopausal women (age, 40-59 yr) with an intermediate median bio E2 level of 11 pg/ml (42 pmol/liter) showed age-adjusted correlations of bio E2 levels with trabecular but not with cortical vBMD.

CONCLUSIONS

In women, bio E2 levels are associated with vBMD and some structural bone parameters at low but not high bio E2 levels. Similar to findings in men, the threshold for estrogen deficiency in cortical bone in women appears to be lower than that in trabecular bone.

Dehydroepiandrosterone sulfate and bone resorption rates as reflected by serum levels of C-terminal telopeptide of type I collagen: a study in healthy men

Sex steroid hormones contribute to the physiological regulation of bone turnover in males. To address this issue, we investigated serum estradiol (E2), total testosterone (T), and DHEAS concentrations, along with serum levels of carboxy-terminal telopeptide of type I collagen (sCTx), in a sample of 76 healthy men aged 23 to 87. The concentration of sCTx declined with age. Both T and DHEAS, at variance with E2, showed a significant age-related decline. T, DHEAS and sCTx significantly (p<0.01) correlated with each other. DHEAS and T were significantly associated after correcting for age (r=0.35, p=0.002) or body mass index (r=0.65, p<0.0001). DHEAS, but not T, significantly correlated with sCTx after correcting for age (r=0.26, p=0.026, and r=0.20, p=0.08, respectively). Stepwise multiple regression analysis showed that only DHEAS (but not T or E2) was a significant independent predictor of sCTx (p=0.0001). Our results show that adrenal androgens play a crucial role in regulating bone resorption in aging men.

Testosterone increases bone mineral density in female-to-male transsexuals: a case series of 15 subjects

OBJECTIVE

Testosterone therapy for osteoporosis has not been studied extensively in women because of its potential to cause virilization. Female-to-male transsexuals are genetic females who suffer from gender dysphoria and thus take supra-physiologic doses of testosterone to change from the female to male phenotype. The aim of this study is to examine the effects of testosterone treatment on the genetic female skeleton.

PATIENTS AND DESIGN

A group of 15 female-to-male transsexuals was prospectively enrolled for observation over a 2-year period. The subjects had a mean age of 37.0 +/- 3.0 years. All of the subjects self-administered testosterone esters intramuscularly at a mean dose of 70.7 +/- 4.5 mg weekly.

MEASUREMENTS

The subjects had measurements of bone mineral density (BMD) by dual X-ray absorptiometry (DXA) of the femoral neck and spine (L2-L4) at 12-month intervals. They had determinations of serum oestradiol, testosterone, soluble RANKL (sRANKL), osteoprotegerin (OPG) and urine N-telopeptide (NTX) at the date of enrolment and at the end of 2 years. results There was a significant positive increase in mean BMD of 7.8% at the femoral neck and a nonsignificant increase in mean BMD of 3.1% at the spine over 2 years. The levels of testosterone reached the upper normal range for males and the levels of oestradiol declined to near the postmenopausal range. sRANKL levels decreased significantly in female-to-male transsexuals who newly initiated testosterone therapy. There was no significant change in urine NTX or serum OPG during the study.

CONCLUSIONS

We conclude that supra-physiologic testosterone therapy increases BMD at the hip while maintaining BMD at the spine in female-to-male transsexuals. The effects of testosterone may be the result of testosterone hormone directly acting on the bone or indirectly through aromatization to oestradiol. Lower RANKL levels coupled with unchanged OPG levels results in an increased OPG/RANKL ratio, which may be beneficial to the bone by inhibiting osteoclastogenesis.

Kinase-mediated regulation of common transcription factors accounts for the bone-protective effects of sex steroids

It has been found that 4-estren-3alpha,17beta-diol, a synthetic ligand for the estrogen receptor (ER) or androgen receptor (AR), which does not affect classical transcription, reverses bone loss in ovariectomized females or orchidectomized males without affecting the uterus or seminal vesicles, demonstrating that the classical genotropic actions of sex steroid receptors are dispensable for their bone-protective effects, but indispensable for their effects on reproductive organs. We have now investigated the mechanism of action of this compound. We report that, identically to 17beta-estradiol or dihydrotestosterone, but differently from raloxifene, estren alters the activity of Elk-1, CCAAT enhancer binding protein-beta (C/EBPbeta), and cyclic adenosine monophosphate-response element binding protein (CREB), or c-Jun/c-Fos by an extranuclear action of the ER or AR, resulting in activation of the Src/Shc/ERK pathway or downregulation of JNK, respectively. All of these effects are non-sex specific, require only the ligand-binding domain of the receptor, and are indispensable for the antiapoptotic action of these ligands on osteoblastic and HeLa cells. Moreover, administration of 17beta-estradiol or 4-estren-3alpha,17beta-diol to ovariectomized mice induces phosphorylation of ERKs, Elk-1, and C/EBPbeta, downregulates c-Jun, and upregulates the expression of egr-1, an ERK/SRE target gene. Kinase-initiated regulation of commonly used transcription factors offers a molecular explanation for the profound skeletal effects of sex steroid receptor ligands, including synthetic ones that are devoid of classical transcriptional activity.