Estrogen metabolism modulates bone density in men

Effects of Isoflavonoid and Vitamin D Synergism on Bone Mineral Density-A Systematic and Critical Review

Phytoestrogens are non-steroidal plant compounds, which bind to α and β estrogen receptors, thereby causing specific effects. The best-known group of phytoestrogens are flavonoids, including isoflavonoids-genistein and daidzein. They play a role in the metabolism of bone tissue, improving its density and preventing bone loss, which contributes to reducing the risk of fractures. Vitamin D is found in the form of cholecalciferol (vitamin D3) and ergocalciferol (vitamin D2) and is traditionally recognized as a regulator of bone metabolism. The aim of this review was to evaluate the synergistic effect of isoflavonoids and vitamin D on bone mineral density (BMD). The MEDLINE (PubMed), Scopus and Cochrane databases were searched independently by two authors. The search strategy included controlled vocabulary and keywords. Reference publications did not provide consistent data regarding the synergistic effect of isoflavonoids on BMD. Some studies demonstrated a positive synergistic effect of these compounds, whereas in others, the authors did not observe any significant differences. Therefore, further research on the synergism of isoflavonoids and vitamin D may contribute to a significant progress in the prevention and treatment of osteoporosis.

Whole Genome Sequencing Unravels New Genetic Determinants of Early-Onset Familial Osteoporosis and Low BMD in Malta

Background: Osteoporosis is a skeletal disease with a strong genetic background. The study aimed to identify the genetic determinants of early-onset familial osteoporosis and low bone mineral density (BMD) in a two-generation Maltese family. Methods: Fifteen relatives aged between 28–74 years were recruited. Whole genome sequencing was conducted on 12 relatives and shortlisted variants were genotyped in the Malta Osteoporotic Fracture Study (MOFS) for replication. Results: Sequential variant filtering following a dominant inheritance pattern identified rare missense variants within SELP, TGF-β2 and ADAMTS20, all of which were predicted to be likely pathogenic and participate in osteoimmunology. TGF-β2 c.1136C>T was identified in five individuals from the MOFS in heterozygosity, four of whom had osteopenia/osteoporosis at the lumbar spine and hip, and/or had sustained a low-trauma fracture. Heterozygosity for the ADAMTS20 c.4090A>T was accompanied by lower total hip BMD (p = 0.018) and lower total serum calcium levels in MOFS (p < 0.01), recapitulating the findings from the family. Women carrying at least one copy of the alternative allele (TC/CC) for SELP c.2177T>C exhibited a tendency for lower lumbar spine BMD and/or wrist fracture history relative to women with TT genotype. Conclusions: Our findings suggest that the identified variants, alone or in combination, could be causal factors of familial osteoporosis and low BMD, requiring replication in larger collections.

In Men With Obesity, T2DM Is Associated With Poor Trabecular Microarchitecture and Bone Strength and Low Bone Turnover

INTRODUCTION

Obesity and type 2 Diabetes (T2D) are both associated with greater bone mineral density (BMD) but increased risk of fractures. The effect of the combination of both conditions on bone metabolism, microarchitecture, and strength in the obese population remains unknown.

METHODS

Data from 112 obese men were collected. Bone turnover and biochemical markers were measured by enzyme-linked immunosorbent assay, body composition and BMD at all sites were assessed by dual energy X-ray absorptiometry, whereas bone microarchitecture and strength (stiffness and failure load) were measured by high-resolution peripheral computed tomography. Data were compared among metabolically healthy obese (MHO) and metabolically unhealthy obese (MUHO) with and without T2D and between obese without and with T2D.

RESULTS

Compared to MHO and MUHO without T2D, MUHO with T2D had significantly lower levels of osteocalcin ((7.49 ± 3.0 and 6.03 ± 2.47 vs 4.24 ± 2.72 ng/mL, respectively, P = 0.003) and C-terminal telopeptide of type I collagen (CTx) (0.28 ± 0.10 and 0.29 ± 0.13 vs 0.21 ± 0.15 ng/mL, respectively, P = 0.02). Dividing our subjects simply into those with and without T2D showed that obese men with T2D had significantly lower levels of osteocalcin (P = 0.003) and CTx (P = 0.005), greater trabecular separation at the tibia and radius (P = 0.03 and P = 0.04, respectively), and lower tibial failure load and stiffness (both P = 0.04), relative to obese men without T2D.

CONCLUSION

In men, the combination of obesity and T2D is associated with reduced bone turnover and poorer trabecular bone microarchitecture and bone strength compared to those who are obese but without T2D, suggesting worse bone disease.

Lean mass and peak bone mineral density

Objectives

The association between body composition parameters and peak bone mineral density is not well documented. The aim of this study is to assess the relative contributions of lean mass and fat mass on peak bone mineral density (BMD).

Methods

The study involved 416 women and 334 men aged between 20 and 30 years who were participants in the population-based Vietnam Osteoporosis Study. Whole body composition parameters (eg, fat mass and lean mass) and BMD at the lumbar spine and femoral neck were measured by dual-energy X-ray absorptiometry. The association between lean mass and fat mass and BMD was analyzed by the linear regression model using the Least Absolute Shrinkage and Selection Operator (LASSO).

Results

Peak BMD in men was higher than women, and the difference was more pronounced at the femoral neck (average difference: 0.123 g/cm²; 95% confidence interval [CI] 0.105–0.141 g/cm²) than at the lumbar spine (average difference 0.019 g/cm²; 95% CI, 0.005–0.036 g/cm²). Results of LASSO regression indicated that lean mass was the only predictor of BMD for either men or women. Each kilogram increase in lean mass was associated with ∼0.01 g/cm² increase in BMD. Lean mass alone explained 16% and 36% of variation in lumbar spine and femoral neck BMD, respectively.

Conclusions

Lean mass, not fat mass, is the main determinant of peak bone mineral density. This finding implies that good physical activity during adulthood can contribute to the maximization of peak bone mass during adulthood.

Age and sex effects on the relationship between body composition and hip geometric structure in males and females from East China

The study finds bone mineral density is the principal determinant of hip geometry and lean mass is a better determinant than fat mass in Chinese. Moreover, the impact of fat on skeleton differs with age, with a negative effect in young people but a more positive effect in elderly.

PURPOSE

The aim of this study was to examine whether the correlation between body composition including bone mineral density (BMD), lean mass (LM) and fat mass (FM), and hip geometric structure change with aging in males and females from East China.

METHODS

It was a cross-section study. A total of 1168 healthy male and 1066 healthy females in Shanghai were divided into six groups based on their age and sex. All participants were evaluated by assessing the BMD of lumber spine and proximal hip, total LM, total FM, and geometric parameters of the hip such as the cross-sectional area (CSA), average cortical thickness (ACT), and the buckling ratio (BR) at the narrow neck (NN), the intertrochanter (IT), and the shaft (FS).

RESULTS

Among the three body composition, the correlation between hip BMD and hip geometric structure was strongest. LM showed significantly positive correlations with CSA. FM showed negative or little positive correlation with hip geometry in the young group. However, the degree of the contribution of FM to hip geometric structure became substantially positive with aging. Limb LM produced the largest positive contribution to CSA and ACT at all three regions in young males. However, in older males the trunk LM produced the largest positive contribution to CSA and ACT.

CONCLUSIONS

Among all body composition parameters, hip BMD showed the largest correlation with hip geometric structure, with LM showing the second largest. The impact of FM and LM on hip geometry changed with aging and with different distributions of lean mass and fat mass.

Fat Mass Follows a U-Shaped Distribution Based on Estradiol Levels in Postmenopausal Women

OBJECTIVE

Estradiol (E2) regulates adipose tissue resulting in increased fat mass (FM) with declining E2. However, increased visceral fat and hyperestrogenemia are features of obese individuals. It is possible that adipocytes in obese individuals are less sensitive to E2 resulting in higher FM. Our objective is to identify the range of serum E2 for which postmenopausal women have the lowest FM and best body composition.

METHODS

Cross-sectional data from 252 community-dwelling postmenopausal women, 42-90 years old. Subjects were stratified into categories of E2 (pg/ml): (1) ≤10.5; (2) 10.6-13.9; (3) 14.0-17.4; and (4) ≥17.5. Body composition by dual-energy X-ray absorptiometry. Serum E2 by radioimmunoassay. Between-group comparisons by analysis of covariance.

RESULTS

E2 linearly increased with increasing body weight and body mass index (r = 0.15 and p = 0.01 for both), but not with total FM (kg) or % FM (r = 0.07, p = 0.34 and r = -0.04, p = 0.56, respectively). However, total FM (kg) followed a U-shaped distribution and was significantly lower in group 3 (27.6 ± 10.6), compared with groups 1: (34.6 ± 12.5), 2: (34.0 ± 12.4), and 4: (37.0 ± 10.6), p = 0.005. % FM was also lowest in group 3. While fat-free mass (FFM, kg) increased with increasing E2 (p < 0.001), % FFM was highest in group 3.

CONCLUSION

In our population of postmenopausal women, FM followed a U-shaped distribution according to E2 levels. E2 between 14.0 and 17.4 pg/ml is associated with the best body composition, i.e., lowest total and % FM and highest % FFM. Given the role of E2 in regulating body fat, high FM at the high end of the E2 spectrum may suggest reduced E2 sensitivity in adipocytes among obese postmenopausal women.

CLINICAL TRIALS

ClinicalTrials.gov identifier: NCT00146107.

Aged-Related Changes in Body Composition and Association between Body Composition with Bone Mass Density by Body Mass Index in Chinese Han Men over 50-year-old

OBJECTIVES

Aging, body composition, and body mass index (BMI) are important factors in bone mineral density (BMD). Although several studies have investigated the various parameters and factors that differentially influence BMD, the results have been inconsistent. Thus, the primary goal of the present study was to further characterize the relationships of aging, body composition parameters, and BMI with BMD in Chinese Han males older than 50 years.

METHODS

The present study was a retrospective analysis of the body composition, BMI, and BMD of 358 Chinese male outpatients between 50 and 89 years of age that were recruited from our hospital between 2009 and 2011. Qualified subjects were stratified according to age and BMI as follows: 50-59 (n = 35), 60-69 (n = 123), 70-79 (n = 93), and 80-89 (n = 107) years of age and low weight (BMI: < 20 kg/m2; n = 21), medium weight (20 ≤ BMI < 24 kg/m2; n = 118), overweight (24 ≤ BMI < 28 kg/m2; n = 178), and obese (BMI ≥ 28 kg/m2; n = 41). Dual-energy X-ray absorptiometry (DEXA) was used to assess bone mineral content (BMC), lean mass (LM), fat mass (FM), fat-free mass (FFM), lumbar spine (L1-L4) BMD, femoral neck BMD, and total hip BMD. Additionally, the FM index (FMI; FM/height2), LM index (LMI; LM/height2), FFM index (FFMI; [BMC+LM]/height2), percentage of BMC (%BMC; BMC/[BMC+FM+LM] × 100%), percentage of FM (%FM; FM/[BMC+FM+LM] × 100%), and percentage of LM (%LM; LM/(BMC+FM+LM) × 100%) were calculated. Osteopenia or osteoporosis was identified using the criteria and T-score of the World Health Organization.

RESULTS

Although there were no significant differences in BMI among the age groups, there was a significant decline in height and weight according to age (p < 0.0001 and p = 0.0002, respectively). The LMI and FFMI also declined with age (both p < 0.0001) whereas the FMI exhibited a significant increase that peaked in the 80-89-years group (p = 0.0145). Although the absolute values of BMC and LM declined with age (p = 0.0031 and p < 0.0001, respectively), there was no significant difference in FM. In terms of body composition, there were no significant differences in %BMC but there was an increase in %FM (p < 0.0001) and a decrease in %LM (p < 0.0001) with age. The femoral neck and total hip BMD significantly declined with age (p < 0.0001 and p = 0.0027, respectively) but there were no differences in L1-L4. BMD increased at all sites (all p < 0.01) as BMI increased but there were declines in the detection rates of osteoporosis and osteopenia (both p < 0.001). A logistic regression revealed that when the medium weight group was given a BMI value of 1, a decline in BMI was an independent risk factor of osteoporosis or osteopenia, while an increase in BMI was a protective factor for BMD. At the same time, BMD in L1-L4 exhibited a significant positive association with FMI (p = 0.0003) and the femoral neck and total hip BMDs had significant positive associations with FFMI and LMI, respectively (both p < 0.0001).

CONCLUSIONS

These data indicate that LMI and FFMI exhibited significant negative associations with aging in Chinese Han males older than 50 years, whereas FMI had a positive association. BMD in the femoral neck and total hip declined with age but an increased BMI was protective for BMD. LMI and FFMI were protective for BMD in the femoral neck and total hip.

The unsolved case of "bone-impairing analgesics": the endocrine effects of opioids on bone metabolism

The current literature describes the possible risks for bone fracture in chronic analgesics users. There are three main hypotheses that could explain the increased risk of fracture associated with central analgesics, such as opioids: 1) the increased risk of falls caused by central nervous system effects, including sedation and dizziness; 2) reduced bone mass density caused by the direct opioid effect on osteoblasts; and 3) chronic opioid-induced hypogonadism. The impact of opioids varies by sex and among the type of opioid used (less, for example, for tapentadol and buprenorphine). Opioid-associated androgen deficiency is correlated with an increased risk of osteoporosis; thus, despite that standards have not been established for monitoring and treating opioid-induced hypogonadism or hypoadrenalism, all patients chronically taking opioids (particularly at doses ≥100 mg morphine daily) should be monitored for the early detection of hormonal impairment and low bone mass density.

Differential effects of adiponectin in osteoblast-like cells

The skeleton should maintain an adequate volume, vigour and strength to carry out the role for which it is designed: to hold the whole soft tissue mass that shapes the body and to protect the vital organs. To fulfil this task a satisfactory food intake is required and regulators that are released in the feeding and fasting states, among other signals indicate how much soft mass needs to be built up. Those signals include the secretion of adipocytokines which could represent a relevant link between soft mass (adipose tissue) and skeleton. We studied the presence of adiponectin receptors (AdipoR1, AdipoR2) and its direct effects in osteosarcoma cell line Saos-2. The results indicated that adiponectin receptors were present in the osteoblastic cells with a higher expression of AdipoR1. Human recombinant globular adiponectin was able to increase viability levels and decrease cytotoxicity rates in cell cultures. Also, adiponectin significantly inhibited alkaline phosphatase activity in supernatants. Osteoprotegerin mRNA expression was significantly reduced after 72 h treatment. The FOS induction was studied and the results exhibited a significant increase caused by adiponectin. In conclusion, all these observations suggest that adiponectin influences bone metabolism decreasing the levels of bone formation. Regulators of adiponectin or its receptors could be circulating to modulate the activities of this peptide.

The alliance of mesenchymal stem cells, bone, and diabetes

Bone fragility has emerged as a new complication of diabetes. Several mechanisms in diabetes may influence bone homeostasis by impairing the action between osteoblasts, osteoclasts, and osteocytes and/or changing the structural properties of the bone tissue. Some of these mechanisms can potentially alter the fate of mesenchymal stem cells, the initial precursor of the osteoblast. In this review, we describe the main factors that impair bone health in diabetic patients and their clinical impact.

Relationship between Weight, Body Mass Index, and Bone Mineral Density in Men Referred for Dual-Energy X-Ray Absorptiometry Scan in Isfahan, Iran

Objective. Although several studies have investigated the association between body mass index (BMI) and bone mineral density (BMD), the results are inconsistent. The aim of this study was to further investigate the relation between BMI, weight and BMD in an Iranian men population. Methods. A total of 230 men 50-79 years old were examined. All men underwent a standard BMD scans of hip (total hip, femoral neck, trochanter, and femoral shaft) and lumbar vertebrae (L2-L4) using a Dual-Energy X-ray Absorptiometry (DXA) scan and examination of body size. Participants were categorised in two BMI group: normal weight <25.0 kg/m(2) and overweight and obese, BMI ≥ 25 kg/m(2). Results. Compared to men with BMI ≥ 25, the age-adjusted odds ratio of osteopenia was 2.2 (95% CI 0.85, 5.93) and for osteoporosis was 4.4 (1.51, 12.87) for men with BMI < 25. It was noted that BMI and weight was associated with a high BMD, compatible with a diagnosis of osteoporosis. Conclusions. These data indicate that both BMI and weight are associated with BMD of hip and vertebrae and overweight and obesity decreased the risk for osteoporosis. The results of this study highlight the need for osteoporosis prevention strategies in elderly men as well as postmenopausal women.

Association between physical activity and urinary estrogens and estrogen metabolites in premenopausal women

OBJECTIVE

The objective of the study was to evaluate in premenopausal women the relationships of physically active and sedentary behaviors reported for adulthood and adolescence with a comprehensive profile of estrogen metabolism.

METHODOLOGY

Fifteen estrogens and estrogen metabolites (jointly termed EM) were measured using liquid chromatography-tandem mass spectrometry in luteal phase urines from 603 premenopausal women in the Nurses' Health Study II. Geometric means of individual EM, metabolic pathway groups, and pathway ratios were examined by level of exposure after adjustment for age, body mass index, alcohol intake, menstrual cycle length, and sample collection timing.

RESULTS

High overall physical activity in adulthood (42+ metabolic equivalent h/wk vs. <3 metabolic equivalent h/wk) was associated with a 15% lower level of urinary estradiol (Ptrend=0.03) and 15% lower level of 16-hydroxylation pathway EM (Ptrend=0.03). Levels of 2- and 4-hydroxylation pathway EM did not differ significantly by physical activity. High overall activity was also positively associated with four ratios: 2-pathway EM to parent estrogens (Ptrend=0.05), 2-pathway catechols to parent estrogens (Ptrend=0.03), 2-pathway catechols to methylated 2-pathway catechols (Ptrend<0.01), and 2-hydroxyestrone to 16α-hydroxyestrone (Ptrend=0.01). Similar patterns of association were noted for walking and vigorous physical activity, but there was little evidence of associations with sedentary behaviors or activity during adolescence.

CONCLUSIONS

High levels of physical activity were associated with lower levels of parent estrogens and 16-hydroxylation pathway EM and preferential metabolism to 2-pathway catechols. The results of our analysis, the largest, most comprehensive examination of physical activity and estrogen metabolism to date, may be useful in future studies investigating the etiology of diseases linked to both physical activity and endogenous estrogen.

Age and sex effects on the association between body composition and bone mineral density in healthy Chinese men and women

OBJECTIVE

Many studies have examined the relationships between body composition and bone mineral density (BMD), but little attention has been given to how these relationships vary by age and sex. The aim of this study was to investigate the distributions of lean mass (LM), fat mass (FM), and BMD and the correlation between body composition and BMD in Chinese men and women of different ages.

METHODS

In total, the body compositions of 1,475 men and 1,534 women aged 20 to 96 years were analyzed. Using dual-energy x-ray absorptiometry, we measured the BMD of the spine, femur, and total body and the LM, FM, and percentage of body fat (Fat %). The population was divided into groups based on age and sex: young, premenopausal, and postmenopausal women and young, middle-aged, and older men. The correlations between BMD and variables of body composition were investigated using the Pearson correlation test and multiple regression analysis.

RESULTS

The peak BMD values of the spine, femur, and total body are observed in women aged 30 to 39, 20 to 29, and 30 to 39 years, respectively, and in men aged 20 to 29 years at all sites. The peak LM, FM, and Fat % values were observed at age 40 to 49, 60 to 69, and 70 to 79 years in women, respectively, and at 40 to 49, 70 to 79, and 70 to 79 years in men, respectively. A statistically significant correlation was observed between LM and BMD of all sites (r = 0.253-0.591, P < 0.01) in all groups. However, FM was significantly correlated to BMD only in postmenopausal women and older men (r = 0.089-0.336, P < 0.01). Fat % negatively correlated to BMD in young people (r = -0.169 to -0.366, P < 0.05). When stepwise regression models were analyzed, LM remained the strongest predictor of total body, spine, and femur BMD (standardized coefficients = 0.264-0.637, P < 0.001) in Chinese men and women of different ages.

CONCLUSIONS

We believe that LM is the strongest predictor of BMD at all ages for Chinese men and women, even though positive correlations between FM and BMD existed in old people.

Increased 2-hydroxylation of estrogen is associated with lower body fat and increased lean body mass in postmenopausal women

Menopause is associated with changes in bone, muscle and fat mass. The importance of postmenopausal estrogen metabolism in bone health has been established. However, its relationship to body composition in postmenopausal women remains undetermined. The objective of this study is to determine the association between estrogen metabolism and body composition in postmenopausal women. This is a cross sectional study of 97 postmenopausal Caucasian women, 49-80 y.o., ≥1 year from the last normal menstrual period or those who have had oophorectomy. Inactive [2-hydroxyestrone (2OHE(1))] and active [16α-hydroxyestrone (16α-OHE(1))] urinary metabolites of estrogen were measured by ELISA. The whole and regional body composition was measured by DXA. We have found that both 2OHE(1), and 2OHE(1)/16α-OHE(1) ratio were negatively correlated with % total fat, and % truncal fat but positively correlated with % total lean mass. Comparing the fat and lean parameters of body composition according to tertiles of 2OHE(1) and 2OHE(1)/16αOHE(1) ratio showed that subjects in the lowest tertiles, had the highest % total fat, and % truncal fat and the lowest % total lean mass. Multiple regression analysis also showed 2OHE(1) and calcium intake as statistically significant predictors of all body composition parameters. In conclusion, in postmenopausal women, an increase in the metabolism of estrogen towards the inactive metabolites is associated with lower body fat and higher lean mass than those with predominance of the metabolism towards the active metabolites.

Elevated incidence of fractures in solid-organ transplant recipients on glucocorticoid-sparing immunosuppressive regimens

This study was conducted to assess the occurrence of fractures in solid-organ transplant recipients. Methods. Medical record review and surveys were performed. Patients received less than 6 months of glucocorticoids. Results. Of 351 transplant patients, 175 patients provided fracture information, with 48 (27.4%) having fractured since transplant (2-6 years). Transplants included 19 kidney/liver (50% male), 47 kidney/pancreas (53% male), 92 liver (65% male), and 17 pancreas transplants (41% male). Age at transplant was 50.8 ± 10.3 years. Fractures were equally seen across both genders and transplant types. Calcium supplementation (n = 94) and bisphosphonate therapy (n = 52) were observed, and an association with a lower risk of fractures was noted for bisphosphonate users (OR = 0.45 95% C.I. 0.24, 0.85). Fracture location included 8 (16.7%) foot, 12 (25.0%) vertebral, 3 (6.3%) hand, 2 (4.2%) humerus, 5 (10.4%) wrist, 10 (20.8%) fractures at other sites, and 7 (14.6%) multiple fractures. The estimated relative risk of fracture was nearly seventeen-times higher in male liver transplant recipients ages 45-64 years compared with the general male population, and comparable to fracture rates on conventional immunosuppressant regimens. Conclusion. We identify a high frequency of fractures in transplant recipients despite limited glucocorticoid use.

Bone and muscle loss after spinal cord injury: organ interactions

Spinal cord injury (SCI) results in paralysis and marked loss of skeletal muscle and bone below the level of injury. Modest muscle activity prevents atrophy, whereas much larger--and as yet poorly defined--bone loading seems necessary to prevent bone loss. Once established, bone loss may be irreversible. SCI is associated with reductions in growth hormone, IGF-1, and testosterone, deficiencies likely to exacerbate further loss of muscle and bone. Reduced muscle mass and inactivity are assumed to be contributors to the high prevalence of insulin resistance and diabetes in this population. Alterations in muscle gene expression after SCI share common features with other muscle loss states, but even so, show distinct profiles, possibly reflecting influences of neuromuscular activity due to spasticity. Changes in bone cells and markers after SCI have similarities with other conditions of unloading, although after SCI these changes are much more dramatic, perhaps reflecting the much greater magnitude of unloading. Adiposity and marrow fat are increased after SCI with intriguing, though poorly understood, implications for the function of skeletal muscle and bone cells.

Vasomotor symptoms and coronary artery calcium in postmenopausal women

OBJECTIVE

We assessed whether vasomotor symptoms (VMS) are associated with coronary artery calcium (CAC) and how hormone therapy (HT) may influence this association.

METHODS

Participants were a subset of women aged 50 to 59 years with a history of hysterectomy who were enrolled in the Women's Health Initiative (WHI) estrogen-alone clinical trial and underwent a CT scan of the chest at the end of the trial to determine CAC. Participants provided information about VMS (hot flashes and/or night sweats), as well as HT use, on self-administered questionnaires at trial baseline.

RESULTS

The sample consisted of 918 women with a mean (SD) age of 55.1 (2.8) years at WHI randomization and 64.8 (2.9) years at CAC ascertainment. The prevalence of a CAC score higher than 0 was 46%, whereas the prevalence of a CAC score of 10 or higher and higher than 100 was 39% and 19%, respectively. At randomization, 77% reported a history of any VMS at any time before or at enrollment in the WHI, whereas 20% reported any VMS present only at enrollment. Compared with those without a history of any VMS and after adjustment for potential confounders, a history of any VMS at any time up to and including WHI enrollment was associated with significantly reduced odds for CAC higher than 0 (odds ratio, 0.66; 95% CI, 0.45-0.98). Moreover, as duration of HT increased, the inverse association between any VMS and CAC moved toward the null.

CONCLUSIONS

A history of any VMS was significantly associated with reduced odds for CAC independent of traditional cardiovascular disease risk factors and other relevant covariates. This association seems to be influenced by duration of HT.

Early smoking is associated with peak bone mass and prevalent fractures in young, healthy men

Smoking is associated with lower areal bone mineral density (aBMD) and higher fracture risk, although most evidence has been derived from studies in elderly subjects. This study investigates smoking habits in relation to areal and volumetric bone parameters and fracture prevalence in young, healthy males at peak bone mass. Healthy male siblings (n = 677) at the age of peak bone mass (25 to 45 years) were recruited in a cross-sectional population-based study. Trabecular and cortical bone parameters of the radius and cortical bone parameters of the tibia were assessed using peripheral quantitative computed tomography (pQCT). Areal bone mass was determined using dual energy X-ray absorptiometry (DXA). Sex steroids and bone markers were determined using immunoassays. Prevalent fractures and smoking habits were assessed using questionnaires. Self-reported fractures were more prevalent in the current and early smokers than in the never smokers (p < .05), with a fracture prevalence odds ratio for early smokers of 1.96 (95% confidence interval 1.18-3.24) after adjustment for age, weight, educational level, and alcohol use and exclusion of childhood fractures. Current smoking was associated with a larger endosteal circumference (beta = 0.027 +/- 0.009, p = .016) and a decreased cortical thickness (beta = -0.034 +/- 0.01, p = .020) at the tibia. In particular, early smokers (< or =16 years) had a high fracture risk and lower areal BMD, together with a lower cortical bone area at the tibia and lower trabecular and cortical bone density at the radius. An interaction between free estradiol and current smoking was observed in statistical models predicting cortical area and thickness (beta = 0.29 +/- 0.11, p = .01). In conclusion, smoking at a young age is associated with unfavorable bone geometry and density and is associated with increased fracture prevalence, providing arguments for a disturbed acquisition of peak bone mass during puberty by smoking, possibly owing to an interaction with sex steroid action.

Age-related changes in sex steroid levels influence bone mineral density in healthy Indian men

SUMMARY

Age-related changes in sex steroid levels and its contribution to variations in rate of bone loss among men is unclear. Although, Bio-T and Bio-E(2) levels declined with age and depicted an association with BMD in healthy Indian men, Bio-E(2) was found to be an independent predictor of BMD.

INTRODUCTION

Ethnicity influences sex steroid levels, therefore, their role in pathogenesis of low bone mass needs to be established in various populations. We assessed the extent of changes in sex steroid levels with age and related these to bone mineral density (BMD) in healthy Indian men.

METHODS

Total testosterone (TT), estradiol (E(2)), sex hormone-binding globulin (SHBG), PTH, osteocalcin (OC), and c-terminal telopeptide (CTX) were measured in 330 men aged 20-55 years and correlated with BMD measured by DXA.

RESULTS

Both Bio-T (1% per year) and Bio-E(2) (0.8% per year) levels decreased significantly in ageing men, whereas TT (0.4% per year) and E(2) (0.3% per year) levels decreased only marginally with age. In contrast, SHBG (1.4% per year) and PTH (1% per year) levels increased significantly with age. Serum TT (r = 0.19, p = 0.01) and Bio-T (r = 0.2, p = 0.01) levels were associated positively with BMD at spine, whereas E(2) and Bio-E(2) levels were associated with BMD at spine [E (2) (r = 0.31, p < 0.0001); Bio-E(2) r = 0.37, p < 0.0001] and femur (E(2) r = 0.26, p = 0.001; Bio-E(2) r = 0.27, p = 0.001). Men in the lowest quartile of Bio-E(2) were associated with lower BMD and higher bone turnover.

CONCLUSIONS

Age-related decrease in bioavailable sex steroid levels is associated with BMD in healthy Indian men. Bio-E(2) was found to be an independent predictor of BMD.

Effects of testosterone undecanoate administered alone or in combination with letrozole or dutasteride in female to male transsexuals

INTRODUCTION

Testosterone undecanoate (TU) has potential as androgen therapy for ovariectomized female to male (FtM) transsexual subjects; however, the long-term physiologic effects of TU treatment, the significance of testosterone (T), and the T metabolites dihydrotestosterone (DHT) and estradiol (E) on specific outcome parameters are currently unknown.

AIM

The aim of this study was to investigate the long-term treatment of TU with regard to bone metabolism, body composition, and lipid profile in FtM subjects, and to evaluate the relationship between observed effects and circulating levels of T, E, and DHT.

MAIN OUTCOME MEASURES

Circulating follicle-stimulating hormone, luteinizing hormone, T, E, DHT, and lipid concentrations were measured, as well as bone metabolism, body composition, and insulin resistance.

METHODS

This was a 1-year, randomized treatment, open-label, uncontrolled safety study. Fifteen ovariectomized FtM subjects from an outpatient clinic were divided into three groups to receive TU 1,000 mg alone or in combination with oral administration of letrozole (L) 2.5 mg/die or dutasteride (D) 0.5 mg/die for a period of 54 weeks.

RESULTS

TU alone and TU + D treatments were successful in terms of hormone adjustment, did not result in any adverse effects, and were well-tolerated. Bone mineral density decreased by an average of 0.9 g/cm(2) in the TU + L group, and the addition of D resulted in a failure to gain lean mass.

CONCLUSIONS

This study confirmed that TU is a successful and safe treatment for FtM subjects. These data indicate that E has an important role in bone metabolism and that DHT may play a role in muscle metabolism.

Androgens and bone

PURPOSE OF REVIEW

The present review will focus on the most important recent findings with respect to skeletal androgen action. Many studies have indicated that part of the androgen action may be related to the conversion of androgens into estrogens. Therefore, some of the most recent findings of skeletal estrogen action relevant for male skeletal physiology will also be discussed.

RECENT FINDINGS

Androgens and estrogens stimulate bone formation and inhibit bone resorption. Sex steroids may interact with different receptors, target cells and other bone anabolic pathways. Androgen receptor and estrogen receptor signalling appear to be important for male bone formation during growth. Sex steroid signalling may involve genomic and nongenomic pathways, interaction with mechanical loading, the growth hormone/insulin-like growth factor-I axis and/or other bone anabolic pathways. Estrogen receptor alpha in osteoclasts appears to regulate bone resorption in women but not men, whereas androgen receptor signalling in osteoblasts may only partly regulate bone resorption in males.

SUMMARY

The latest developments indicate that androgens and estrogens are important for male bone metabolism and homeostasis and therefore selective estrogen receptor alpha and androgen receptor signalling remain interesting drug targets for the stimulation of bone formation and male skeletal integrity.