Endogenous sex steroids and bone mineral density in healthy Greek postmenopausal women

Sex-specific association of serum dehydroepiandrosterone and its sulfate levels with osteoporosis in type 2 diabetes

INTRODUCTION

This study is to investigate the relation between serum dehydroepiandrosterone (DHEA) and its sulfate (DHEAS) levels and the risk of osteoporosis in patients with T2DM.

MATERIALS AND METHODS

This cross-sectional study involved 938 hospitalized patients with T2DM. Linear regression models were used to explore the relationship between DHEA and DHEAS and the BMD at different skeletal sites. Multinominal logistic regression models and the restricted cubic spline (RCS) were used to evaluate the associations of DHEA and DHEAS with the risks of osteopenia and/or osteoporosis.

RESULTS

In postmenopausal women with T2DM, after adjustment for confounders including testosterone and estradiol, DHEA showed a significant positive correlation with lumbar spine BMD (P = 0.013). Moreover, DHEAS exhibited significant positive correlations with BMD at three skeletal sites: including femoral neck, total hip, and lumbar spine (all P < 0.05). Low DHEA and DHEAS levels were associated with increased risk of osteopenia and/or osteoporosis (all P < 0.05) and the risk of osteoporosis gradually decreased with increasing DHEAS levels (P overall = 0.018, P-nonlinear = 0.559). However, DHEA and DHEAS levels in men over the age of 50 with T2DM were not associated with any of above outcomes.

CONCLUSION

In patients with T2DM, independent of testosterone and estradiol, higher DHEA and DHEAS levels are associated with higher BMD and lower risk of osteopenia/osteoporosis in postmenopausal women but not men over the age of 50.

Association of Endogenous Hormones and Bone Mineral Density in Postmenopausal Women

Aim

The aim of this study was to examine the association between endogenous hormones and bone mineral density (BMD) in postmenopausal women.

Materials and Methods

This was a cross-sectional study of 798 postmenopausal women aged 47-85 years. Data were collected on age, age at menopause, years since menopause, smoking status, body mass index, adiposity, BMD, physical activity, and Vitamin D supplementation. Measured hormonal parameters were: follicle-stimulating hormone (FSH), estradiol, testosterone, dehydroepiandrosterone sulfate, ∆4-androstenedione, cortisol, insulin-like growth factor-1, 25-hydroxyvitamin D, and parathormone (PTH) levels. BMD was measured at the lumbar spine, femoral neck, and total hip using dual-energy X-ray absorptiometry. A directed acyclic graph was used to select potential confounding variables.

Results

Multivariable analysis showed significant associations between cortisol and femoral neck BMD (β: -0.02, 95% confidence interval [CI]: -0.03--0.00), and PTH with femoral neck BMD (β: -0.01, 95% CI: -0.02--0.01) and total hip BMD (β: -0.01, 95% CI: -0.01--0.00). Hormonal factors more likely associated with a higher risk of low BMD (osteopenia or osteoporosis) were FSH (odds ratio [OR]: 1.02, 95% CI: 1.01-1.03) and PTH (OR: 1.02, 95% CI: 1.01-1.04).

Conclusions

Higher cortisol and PTH levels were inversely associated with BMD. Postmenopausal women with higher FSH or PTH levels were likely to have low BMD.

Steroid hormone levels and bone mineral density in women over 65 years of age

Previous studies using immunoassays for steroid measurements have focused on the association between steroid hormone levels and bone mineral density (BMD) in postmenopausal women, obtaining contradictory results. This study aimed to assess this association using a highly sensitive bioanalytical method. A total of 68 postmenopausal women, aged 65-89 years, were enrolled in a cross-sectional study. Measurements of the BMD of the hip and lumbar spine were performed using dual energy X-ray absorptiometry, and serum hormone levels were quantified by gas chromatography and tandem mass spectrometry. Associations between estradiol (E2), testosterone, dehydroepiandrosterone (DHEA), androstenedione and T score levels of the hip and lumbar spine were evaluated, after adjustment for confounding variables. The analysis revealed a statistically significant association between testosterone and the T score of the hip (p = 0.035), but not that of the lumbar spine. No statistically significant associations were found between E2, DHEA, androstenedione and the T scores of the hip and the lumbar spine. Using a highly sensitive hormone assay method, our study identified a significant association between testosterone and BMD of the hip in women over 65 years of age, suggesting that lower testosterone increases the risk of osteoporosis.

Anogenital index and bone mineral density associations after natural and surgical menopause: a preliminary study

OBJECTIVE

The aim of this study was to evaluate postmenopausal women to determine whether an anogenital index (AGI) is associated with bone mineral density (BMD) based on the hypothesis that the effects of menopause are similar for both.

METHODS

A total of 338 generally healthy postmenopausal women who were referred for a routine annual check and 140 women who met the inclusion criteria were enrolled in the study. Based on the menopausal status, the women were classified into natural menopause and surgical menopause. AGI was calculated by dividing anogenital distance by body mass index. The BMD of the femoral neck, body of the femur, and lumbar spine (L1 and L2) was measured using dual-energy x-ray absorptiometry.

RESULTS

There was a statistically significant and same-directional correlation between age and AGI for all cases (r=0.234 and p=0.005). The AGI level decreased as the parity increased (r=-0.582 and p<0.001). The AGI level decreased significantly as the menopause duration was prolonged (r=0.288 and p<0.001). While there was no statistically significant correlation between L2-L4 BMD and AGI (p=0.128), as the femur and femoral neck BMD levels increased, the AGI level increased statistically significantly (r=0.330 and p<0.001, r=0.292 and p<0.001).

CONCLUSION

The AGI levels in healthy postmenopausal women give preliminary information about their BMD status. A decrease in AGI levels may predict lower BMD in postmenopausal women. Further larger and well-controlled studies may be required to determine the relationship between AGI and BMD in the future.

Endogenous DHEAS Is Causally Linked With Lumbar Spine Bone Mineral Density and Forearm Fractures in Women

CONTEXT

A recent pooled analysis of four clinical trials demonstrated that treatment with dehydroepiandrosterone (DHEA) increases lumbar spine bone mineral density (LS-BMD) in women. The causal effect of endogenous adrenal-derived DHEA sulphate (DHEAS) on LS-BMD and fracture risk in women is unknown.

OBJECTIVE

To determine whether circulating DHEAS is causally associated with LS-BMD and fracture risk in women.

METHODS

A 2-sample Mendelian randomization study using genetic predictors of serum DHEAS derived from the largest available female-specific genome wide association study (GWAS) meta-analysis (n = 8565). Genetic associations with dual-energy X-ray absorptiometry-derived BMD (n = 22 900) were obtained from female-specific GWAS summary statistics available from the Genetic Factors for Osteoporosis consortium while individual-level data of 238 565 women of white ancestry from the UK Biobank were used for associations with fractures (11 564 forearm fractures, 2604 hip fractures) and estimated heel BMD by ultrasound (eBMD).

RESULTS

A 1 SD genetically instrumented increase in log serum DHEAS levels was associated with a 0.21 SD increase in LS-BMD (P = 0.01) and a 0.08 SD increase in eBMD (P < 0.001). Genetically predicted DHEAS decreased forearm fracture risk (odds ratio 0.70, 95% CI 0.55-0.88 per SD increase in DHEAS) while no significant causal association with hip fractures was observed.

CONCLUSIONS

Genetically predicted serum DHEAS increases LS-BMD and decreases forearm fracture risk in women. Based on the results of the present study and previous randomized controlled trials of DHEA treatment, we propose that both endogenous adrenal-derived DHEA(S) and pharmacological DHEA treatment improve bone health in women.

Dehydroepiandrosterone and age-related musculoskeletal diseases: Connections and therapeutic implications

Musculoskeletal disorders related to ageing are one of the most common causes of mortality and morbidity among elderly individuals worldwide. The typical constitutive components of the musculoskeletal system, including bone, muscle, and joints, gradually undergo a process of tissue loss and degeneration as a result of life-long mechanical and biological stress, ultimately leading to the onset of a series of age-related musculoskeletal diseases, including osteoporosis (OP), sarcopenia, and osteoarthritis (OA). Dehydroepiandrosterone (DHEA), a precursor of androgen secreted mainly by the adrenal gland, has attracted much attention as a marker for senescence due to its unique age-related changes. This pre-hormone has been publicly regarded as an "antidote for ageing" because of its favourable effect against a wide range of age-related diseases, such as Alzheimer disease, cardiovascular diseases, immunosenescence and skin senescence, though its effect on age-related musculoskeletal diseases has been explored to a lesser extent. In the present review, we summarized the action of DHEA against OP, sarcopenia and OA. Extensive detailed descriptions of the pathogenesis of each of these musculoskeletal disorders are beyond the scope of this review; instead, we aim to highlight the association of changes in DHEA with the processes of OP, sarcopenia and OA. A special focus will also be placed on the overlapping pathogeneses among these three diseases, and the molecular mechanisms underlying the action of DHEA against these diseases are discussed or postulated.

Associations of serum sex hormone binding globulin with bone mineral densities and higher 10-year probability of fractures in postmenopausal women with type 2 diabetes mellitus

Background

Postmenopause and type 2 diabetes mellitus (T2DM) are associated with higher fracture risk. Sex hormones are important in maintaining woman skeleton health. The relationships of sex hormone(s) with bone mineral density (BMD) and fracture risk are still unclear in diabetic-postmenopausal women. This study aimed to investigate the relationships of sex hormones with BMDs and fracture risk in postmenopausal women with T2DM.

Methods

Two hundred and fourteen postmenopausal women with T2DM were included. BMDs at lumbar spine (L2-4), femoral neck (FN) and total hip (TH) were measured by dual-energy X-ray absorptiometry (DXA). The 10-year probability of fractures was accessed by modified fracture risk algorithm (FRAX) tool. Serum concentrations of sex hormones were measured.

Results

Sex hormone binding globulin (SHBG) was a determinant of BMDs at L2-4 (β=-0.199, P<0.05), TH (β=-0.233, P<0.05), major osteoporotic fracture (MOF) (β=0.253, P<0.001) and hip fracture (HF) (β=0.262, P<0.001). Per SD increase in SHBG caused a 2% increase in the risk of osteoporosis/osteopenia. SHBG in quartile-4 was associated with 4.21 higher risk of osteoporosis/osteopenia compared with SHBG in quartile-1.

Conclusions

In postmenopausal women with T2DM, higher serum SHBG tended to be associated with lower BMDs, and increased the risk of osteoporosis/osteopenia and the fracture risk.

The relationship between breast density and bone mineral density in never users of postmenopausal hormone therapy

BACKGROUND

Estrogen is known to affect both mammographic breast density and bone mineral density (BMD), but there are inconsistent results about the association of these density measurements in postmenopausal women. Furthermore, there are scarce data on the relationship between breast density and BMD in never users of postmenopausal hormone therapy.

AIM

In this study, we examined the relationship between mammographic breast density and BMD in postmenopausal women who were never hormone replacement therapy users.

METHODS

A total of 293 postmenopausal women were enrolled in this cross-sectional study. Mammograms and BMD measurements for screening purposes were obtained. Assessment of mammographic breast density was performed by using breast imaging reporting and data system classification. The BMD was measured using dual-energy X-ray absorptiometry of the lumbar spine and femoral neck.

RESULTS

Grade 1 breast density was observed in 64 women (21.8 %), grade 2 in 113 women (38.6 %) and grades 3 and 4 in 116 (39.6 %) women. Breast density decreased with increasing age and body mass index (BMI). Meanwhile, no significant differences were detected in BMD measures of the hip (p = 0.14) and lumbar spine (p = 0.29) among the breast density categories. After adjusting for age and BMI, the differences in the mean BMD at the hip and lumbar spine across the breast density categories remained insignificant (p = 0.26 and 0.11, respectively).

CONCLUSION

There is no evidence of a relationship between mammographic breast density and BMD in postmenopausal women who had never used hormone replacement therapy.

The Association between Dehydroepiandrosterone Sulfate (DHEA-S) and Bone Mineral Density in Korean Men and Women

Background

The relationship between dehydroepiandrosterone sulfate (DHEA-S) and bone mineral density (BMD) is controversial. And findings of most studies that have investigated this relationship are restricted to postmenopausal women. In this study, we investigated the relationship between serum DHEA-S and BMD in both men and women.

Methods

This cross-sectional study evaluated a total of 294 healthy Korean participants through a medical examination program. And a subgroup of 154 participants was subjected to a longitudinal analysis. We measured BMD by dual energy X-ray absorptiometry and assayed DHEA-S by a chemiluminescent immunoassay.

Results

We evaluated the association between serum DHEA-S concentration and BMD at the femur trochanter after adjusting for cofounders such as age, body mass index, lifestyle factors, serum cortisol level, serum insulin-like growth factor 1 (IGF-1) level, and sex. Through our longitudinal study, we found that the changes in BMD at the total spine, at the femur neck, and at the femur trochanter were all smaller in the ΔDHEA-S <0 group than in the ΔDHEA-S >0 group.

Conclusions

We found that there was a positive correlation between serum DHEA-S and femur BMD, which suggests that controlling serum DHEA-S levels may retard age-related BMD reduction in Koreans.

The association between serum dehydroepiandrosterone Sulphate (DHEA-S) level and bone mineral density in Korean men

CONTEXT

Many lines of evidence indicate that dehydroepiandrosterone (DHEA) plays a distinct role in bone metabolism and that its sulphated form (DHEA-S), which is easily measured in blood, may be a potential biomarker of osteoporosis-related phenotypes. However, most previous epidemiologic studies focused on postmenopausal women and reported conflicting results.

OBJECTIVE

We aimed to investigate the association between the serum DHEA-S level and bone mass in men.

DESIGN AND METHODS

This large cross-sectional study included 1089 healthy Korean men who participated in a routine health screening examination. Bone mineral density (BMD) at the lumbar spine, total femur, femur neck, and trochanter and serum DHEA-S level were obtained in all subjects.

RESULTS

After adjustment for age, body mass index, lifestyle factors and serum levels of calcium, phosphorus, testosterone, 25-OH-vitamin D3 and cortisol, higher serum DHEA-S concentrations were associated with higher BMD values at all skeletal sites. Consistently, compared to the subjects in the highest DHEA-S quartile (Q4), those in the lowest DHEA-S quartile (Q1) showed significantly lower BMD values. Multiple logistic regression analyses revealed that the odds ratios for the risk of lower BMD (T-score <-1) increased in a dose-dependent manner across decreasing DHEA-S quartiles and the odds for the risk of lower BMD were 2·59-fold higher in Q1 than in Q4.

CONCLUSION

These findings support previous evidences that DHEA-S has favourable effects on bone mass in men and suggest that a low serum DHEA-S level may be a potential risk factor for male osteoporosis.

A fruit, milk and whole grain dietary pattern is positively associated with bone mineral density in Korean healthy adults

BACKGROUND/OBJECTIVES

Osteoporosis is a major health problem that will grow in burden with ageing of the global population. Modifiable risk factors for osteoporosis, including diet, have significant implications for disease prevention. We examined associations between dietary patterns and bone mineral density (BMD) in a Korean adult population.

SUBJECTS/METHODS

In total, 1828 individuals from the Healthy Twin Cohort were included as subjects. Information on general characteristics, lifestyles and health status was obtained through a health examination, and BMD was assessed using DEXA. Dietary intake was assessed using a 3-day food record, and dietary patterns were examined by factor analysis. Associations between dietary patterns and BMD were examined using mixed linear regression, adjusting for family and twin structure as well as other potential risk factors for bone health.

RESULTS

Four dietary patterns were identified (Rice and kimchi; eggs, meat and flour; Fruit, milk and whole grains; and Fast food and soda). The 'Fruit, milk and whole grains' pattern was associated with a reduced risk of having low BMD in men (odds ratio (OR)=0.38; 95% confidence interval (CI)=0.22-0.67) and women (OR=0.45; 95% CI=0.28-0.72) and was positively associated with BMD at multiple sites. The 'rice and kimchi' pattern had a positive association with only whole-arm BMD in men and women.

CONCLUSIONS

Our results suggest that a dietary pattern with high intake of dairy products, fruits and whole grains may contribute positively to bone health in a Korean adult population, and dietary pattern-based strategies could have potential in promoting bone health.

Low androstenedione/sex hormone binding globulin ratio increases fracture risk in postmenopausal women. The Women's Health in the Lund Area study

The Women's Health in the Lund Area (WHILA) project (n=6917) is a cohort study that started in 1995 and includes a postal questionnaire, physical examination, bone density measurement and blood laboratory analyses. Fracture data have been added, and in this report fracture risk and its association with sex hormones was analysed in postmenopausal women without current hormone therapy (HT). A total of 409 women (median age 56.8 years) with 489 fractures were identified from the postmenopausal women without HT during a median follow-up time of 8.4 years. Lower serum levels of androstenedione (p<0.001), testosterone (p=0.008), androstenedione/sex hormone binding globulin (SHBG) ratio (p<0.001), testosterone/SHBG ratio (p=0.003) and higher levels of SHBG (p=0.005) were observed in women with fractures compared to no fracture. No difference in oestradiol levels was observed. Androstenedione and androstenedione/SHBG ratio were further divided into percentiles. Increased fracture risk was found in postmenopausal women with androstenedione in 5th percentile compared to 11-89th percentile HR 1.51 (95% CI 1.02-2.24). The androstenedione/SHBG ratio (11-89th percentile as reference) showed increased fracture risk in women with low ratio 5th percentile HR 1.75 (95% CI 1.20-2.54) and decreased fracture risk with high ratio 95th percentile HR 0.52 (95% CI 0.28-0.98). An increased fracture risk during follow-up was encountered in postmenopausal women with low serum androstenedione and androstenedione/SHBG ratio at baseline and a decreased fracture risk with high androstenedione/SHBG ratio. This study suggests that postmenopausal osteoporosis is influenced by lower levels of androgens.

Serum sex steroid levels and longitudinal changes in bone density in relation to the final menstrual period

CONTEXT

The associations of serum sex steroid and FSH levels with change of bone mineral density (BMD) across the complete menopausal transition are incompletely understood.

OBJECTIVE

The objective of the study was to examine the associations of annual serum levels of FSH, estradiol (E2), T, and SHBG with the rates of bone loss in 3 phases: pretransmenopausal [baseline to 1 year before the final menstrual period (FMP)], transmenopausal (1 year before to 2 years after the FMP), later postmenopausal (≥ 2 years after the FMP).

DESIGN

The design of the study was a repeated-measures, mixed-effects regression.

SETTING

This was a community-based observational study, with a 10-year follow-up.

PARTICIPANTS

A total of 720 participants of the Study of Women's Health Across the Nation Bone Study participated in the study.

OUTCOME MEASURES

Annualized lumbar spine (LS) and femoral neck (FN) BMD decline was measured.

RESULTS

The mean annual change in BMD was slowest in pretransmenopause (0.27%/year in FN) and fastest in transmenopause (2.16%/year in LS). In the pretransmenopausal phase, for every doubling of FSH level, LS BMD change was faster by -0.32%/year (P < .0001). In the transmenopausal phase, for every doubling of FSH level, LS BMD change was -0.35%/year faster (P < .0001); for every doubling of SHBG level, LS BMD change was -0.36%/year faster (P < .0001). In the later postmenopausal phase, for each doubling of the E2 level, the LS BMD change was slower by +0.26%/year (P = .049); for each SHBG doubling, the LS BMD change was 0.21%/year slower (P = .048). The FN associations were weaker and inconsistent.

CONCLUSIONS

Higher E2 levels and lower FSH levels were associated with lower rates of LS bone loss in some but not all menopausal transition phases.

The association of body composition and sex hormones with quantitative ultrasound parameters at the calcaneus and phalanxes in elderly women

We investigated the associations of body composition and sex hormones with quantitative ultrasound (QUS) parameters carried out at different skeletal sites. In 897 postmenopausal women (64.1 ± 6.6 years) we measured QUS at the calcaneus (stiffness) by Achilles-GE and at phalanxes (amplitude-dependent speed of sound [AD-SOS], bone transmission time [BTT], and ultrasound bone profile index [UBPI]) by Bone Profiler-IGEA. In all subjects we measured fat mass (FM), lean mass (LM), android fat, and gynoid fat by DXA. In all subjects we also assessed serum testosterone (T), estradiol (E(2)), sex-hormone binding globulin, free estrogen index (FEI), free androgen index, 25-hydroxyvitamin D (25OHD), bone alkaline phosphatase (B-ALP), and type I collagen β carboxy telopeptide. Both E(2) and FEI showed weak but significant correlations with stiffness and QUS parameters at phalanxes. No significant relationships were found between T and QUS. BMI and LM were positively correlated with stiffness (r = 0.14 and r = 0.17, respectively), whereas BMI and FM showed negative correlations with AD-SOS, BTT, and UBPI. 25OHD showed positive relationships with stiffness and QUS at phalanxes. In multivariate models LM and age were associated with stiffness whereas E(2) and age were significant predictors of BTT. AD-SOS was negatively associated with FM, B-ALP, and age but positively with E(2) and 25OHD. In postmenopausal women QUS parameters at the calcaneus and at phalanxes are significantly, but diversely, associated with body composition, sex hormones, 25OHD, and bone turnover markers.

Association between DHEAS and bone loss in postmenopausal women: a 15-year longitudinal population-based study

Our aim was to examine the association between serum dehydroepiandrosterone sulfate (DHEAS) at baseline and BMD change at the femoral neck (FN) and lumbar spine (LS) in postmenopausal women during a 15-year follow-up. All participants were from the Chingford Study. BMD at the FN and LS were measured eight times during the 15-year follow-up by dual-energy X-ray absorptiometry. DHEAS at baseline was measured using radioimmunoassay. Data on height, weight, and hormone-replacement therapy (HRT) status were obtained at each visit. Multilevel linear regression modeling was used to examine the association between longitudinal BMD change at the FN and LS and DHEAS at baseline. Postmenopausal women (n = 1,003) aged 45-68 years (mean 54.7) at baseline were included in the study. After adjustment for baseline age, estradiol, HRT, and BMI, BMD at the FN decreased on average 0.49% (95% CI 0.31-0.71%) per year; and the decline was slowed down by 0.028% per squared year. Increase of DHEAS (each micromole per liter) was associated with 0.49% less bone loss at the FN (95% CI 0.21-0.71%, P = 0.001). However, this strong association became slightly weaker over time. Similar but weaker results were obtained for LS BMD. Our data suggest that high serum DHEAS at baseline is associated with less bone loss at both FN and LS and this association diminishes over time. The nature of the association is unclear, but such an association implies that, in managing BMD loss, women might benefit from maintaining a high level of DHEAS.

Endogenous estrogen may prevent bone loss in postmenopausal hemodialysis patients throughout life

SUMMARY

Postmenopausal hemodialysis patients are at risk of complications related to renal mineral and bone disorder, and postmenopausal osteoporosis. In 112 postmenopausal hemodialysis patients, free estrogen index was positively correlated with bone mineral density (BMD) Z-score and the annual percent change of BMD in multiple regression analysis. Endogenous estrogen may prevent bone loss in postmenopausal hemodialysis patients throughout life.

INTRODUCTION

Women on dialysis are not only at risk of developing mineral and bone disorder, but also suffer from postmenopausal osteoporosis. We assessed the effect of sex hormones on bone metabolism in postmenopausal hemodialysis patients.

METHODS

We enrolled 112 postmenopausal hemodialysis patients with a mean age of 68.4 ± 10.4 years. We measured the serum levels of estradiol, testosterone, sex hormone-binding globulin (SHBG), and intact parathyroid hormone (intact-PTH), as well as bone metabolism parameters and radial bone mineral density (BMD). The free estrogen index (FEI) was calculated from the estradiol and SHBG values. After conventional dialysis was performed for 12 months, BMD was measured again and the annual percent change was calculated. Estradiol and SHBG were also measured in 25 postmenopausal women without chronic kidney disease.

RESULTS

Estradiol levels were higher in the hemodialysis patients than in the postmenopausal women without chronic kidney disease. In patients with relatively normal bone turnover (intact-PTH: from 150 to 300 pg/ml), the FEI showed a positive correlation with the BMD Z-score. The annual percent change of BMD showed a positive correlation with the FEI according to multiple regression analysis.

CONCLUSIONS

Endogenous estrogen may prevent bone loss in postmenopausal hemodialysis patients throughout life.

The relationship between bone mineral density and mammographic density in Korean women: the Healthy Twin study

Mammographic density is one of the strong risk factors for breast cancer. A potential mechanism for this association is that cumulative exposure to mammographic density may reflect cumulative exposure to hormones that stimulate cell division in breast stroma and epithelium, which may have corresponding effects on breast cancer development. Bone mineral density (BMD), a marker of lifetime estrogen exposure, has been found to be associated with breast cancer. We examined the association between BMD and mammographic density in a Korean population. Study subjects were 730 Korean women selected from the Healthy Twin study. BMD (g/cm(2)) was measured with dual-energy X-ray absorptiometry. Mammographic density was measured from digital mammograms using a computer-assisted thresholding method. Linear mixed model considering familial correlations and a wide range of covariates was used for analyses. Quantitative genetic analysis was completed using SOLAR. In premenopausal women, positive associations existed between absolute dense area and BMD at ribs, pelvis, and legs, and between percent dense area and BMD at pelvis and legs. However, in postmenopausal women, there was no association between BMD at any site and mammographic density measures. An evaluation of additive genetic cross-trait correlation showed that absolute dense area had a weak-positive additive genetic cross-trait correlation with BMD at ribs and spines after full adjustment of covariates. This finding suggests that the association between mammographic density and breast cancer could, at least in part, be attributable to an estrogen-related hormonal mechanism.

Higher serum free testosterone concentration in older women is associated with greater bone mineral density, lean body mass, and total fat mass: the cardiovascular health study

CONTEXT

The physiological importance of endogenous testosterone (T) in older women is poorly understood.

OBJECTIVE

The aim of the study was to determine the association of higher total and free T levels with bone mineral density (BMD), lean body mass, and fat mass in elderly women.

DESIGN

Total and free T were measured using sensitive assays in 232 community-dwelling women aged 67-94 yr who were enrolled in the Cardiovascular Health Study and had dual-energy x-ray absorptiometry scans. Cross-sectional analyses were performed to examine associations between total and free T and BMD and body composition.

RESULTS

In adjusted models, total T was directly associated with BMD at the lumbar spine (P = 0.04) and hip (P = 0.001), but not body composition outcomes, in all women, and after excluding estrogen users and adjusting for estradiol (P = 0.04 and 0.01, respectively). Free T was positively related to hip BMD, lean body mass, and body fat (all P < 0.05), with more than 10% differences in each outcome between women at the highest and lowest ends of the free T range, with attenuation after excluding estrogen users and adjusting for estradiol.

CONCLUSIONS

In the setting of the low estradiol levels found in older women, circulating T levels were associated with bone density. Women with higher free T levels had greater lean body mass, consistent with the anabolic effect of T, and, in contrast to men, greater fat mass. Mechanistic studies are required to determine whether a causal relationship exists between T, bone, and body composition in this population and the degree to which any T effects are estrogen-independent.

[Serum androgen concentrations and bone mineral density in postmenopausal ovariectomized and non-ovariectomized women]

OBJECTIVE

Compare levels of androgens and bone mineral density (BMD) of ovariectomized (OVX) and non-ovariectomized (NOVX) postmenopausal women. Forty women, 20 OVX and 20 NOVX, (53.9 +/- 4 years) were selected.

METHODS

Total testosterone (TT), free testosterone (FT), androstenedione (AN), dehidroepiandrostenedione (DHEA) and its sulfate (DHEA-S) were measured. BMD was measured in 14 OVX and 16 NOVX.

RESULTS

No differences between groups with regard to age, body mass index (BMI) and time since menopause were found. Mean levels of TT and FT were two-fold higher in NOVX group (60.91 versus 30.17 ng/dL, p = 0.0001; 1.00 versus 0.48 pg/mL, p = 0.003). BMD was not different between groups. Inverse correlations were found between BMI and TT (r = -0.3; p = 0.05); time since menopause and AN (r = -0.35; p = 0.02) and time since menopause and DHEA (r = -0.3; p = 0.01).

CONCLUSION

Bilateral ovariectomy leads to a more severe androgen deficiency than natural menopause in postmenopausal women and did not compromise bone mass.

Association between endogenous plasma hormone concentrations and fracture risk in men and women: the EPIC-Oxford prospective cohort study

Sex steroids have an important role in bone health, however previous studies on fracture risk have been carried out in older populations. The EPIC-Oxford study is a prospective cohort of men and women living in the UK. Five years after recruitment, participants self-reported previous fractures. Sex steroid concentrations (plasma estradiol, testosterone and sex hormone binding globulin) were measured in 436 cases (155 men, 46 premenopausal women and 235 postmenopausal women) with an incident fracture and 868 matched controls. Fracture risk was inversely related to concentrations of estradiol among men (RR for a doubling of estradiol 0.35, 95% CI 0.44-0.96) but there was no association between fracture risk and testosterone levels. There were no clear associations between fracture risk and hormone levels among postmenopausal women, however there was suggestion of an inverse association for both estradiol and testosterone as the RR in the highest compared with the lowest tertile for estradiol was 0.74 (95% CI 0.46, 1.18) and testosterone was 0.75 (95% CI 0.49, 1.16). Among premenopausal women fracture risk was inversely associated with levels of testosterone (RR for doubling of testosterone 0.46, 95% CI 0.26-0.81), with no association between estradiol and fracture risk. SHBG was not associated with risk of fracture among either men or women. In summary, this study finds evidence of an inverse association between endogenous estradiol and risk of fracture in men, and between endogenous testosterone and risk of fracture in premenopausal women but no clear associations among postmenopausal women.

Endogenous estrogen levels and the effects of ultra-low-dose transdermal estradiol therapy on bone turnover and BMD in postmenopausal women

In a randomized controlled trial of a 0.014 mg/d transdermal estradiol patch, serum bone turnover markers decreased to a greater degree in postmenopausal women with lower versus higher endogenous estradiol levels. This suggests that the protective effects of ultra-low-dose estrogen therapy on the postmenopausal skeletal health may depend critically on women's endogenous estrogen levels before treatment.

INTRODUCTION

Postmenopausal women with very low or undetectable estradiol levels have lower BMD, increased bone turnover, and increased risk of hip and vertebral fracture. We assessed whether the effects of ultra-low-dose 0.014 mg/d transdermal estradiol (Menostar; Berlex, Montvale, NJ, USA) on bone turnover and BMD are influenced by endogenous estradiol levels.

MATERIALS AND METHODS

We analyzed data from postmenopausal women (mean age, 66 yr) randomized to an 0.014-mg/d transdermal estradiol patch or placebo in the ultra-low-dose transdermal estrogen (ULTRA) trial. The free estradiol index (FEI), calculated as the ratio of total estradiol (by mass spectometry) to sex hormone-binding globulin (SHBG; by immunoradiometric assay) x 100, was used to estimate bioavailable estradiol at baseline. Among the 382 women who adhered to >or=80% of study medication, we examined change in serum osteocalcin and bone-specific alkaline phosphatase levels at 12 mo and total hip and lumbar spine BMD at 24 mo in each quintile of FEI.

RESULTS

Compared with women in the highest quintile of FEI, those in the lowest quintile of FEI had a 26% greater reduction in bone-specific alkaline phosphatase and 15% greater reduction in osteocalcin in response to ultra-low estradiol treatment (p for trend across quintiles < 0.05). There was a trend toward greater improvement in total hip BMD (p = 0.06) but not spine BMD (p = 0.90) in those with lower versus higher FEI levels.

CONCLUSIONS

The beneficial effects of ultra-low-dose 0.014-mg/d transdermal estrogen therapy on skeletal health may depend critically on women's endogenous estrogen levels before treatment.

CYP17 and COMT gene polymorphisms can influence bone directly, or indirectly through their effects on endogenous sex steroids, in postmenopausal Japanese women

We aimed to assess whether circulating sex steroids would influence bone density and bone loss, whether part of this influence could be explained by genetic variation measured as polymorphisms in candidate genes affecting circulating hormone levels, or whether gene polymorphisms would have direct effects on bone in 229 postmenopausal Japanese women aged 46 years and over who had been followed for eight years (Yokohama Cohort). Bone mineral density (BMD) in the lumbar spine (L), femoral neck (FN), total hip (T) and distal radius (R) was measured every year, and endogenous sex steroid levels were determined at the start of the study. We investigated the polymorphisms of estrogen-metabolizing enzyme gene, CYP17; estrogen biosynthesis (high activity, A2/A2), CYP1A1; hydroxylation (high inducibility, vt/vt) and COMT; inactivation (low activity, L/L) with PCR-based restriction fragment length polymorphism assays. Dehydroepiandrosterone (DHEA) and androstenedione (AND) levels significantly correlated with bone density in both the axial (L) and the appendicular skeleton (FN, T and R) (r=0.194-0.229; P<0.05) whereas estradiol (E2) and AND showed significant correlations with bone change only at the axial skeleton (r=0.205 and r=-0.139, respectively; P<0.05) on the total cohort. These correlations remained significant in thin/normal-weight women [body mass index (BMI) <25 kg/m2)] even after adjustment for years since menopause (YSM) and BMI or age and BMI, suggesting an interaction of BMI and sex steroid/BMD association. On the total cohort, a difference in endogenous DHEA levels between CYP17 homozygote A2 and non-homozygote A2; an increasing trend in AND levels from COMT L/L, L/H, to H/H; and a difference in TS level between COMT homozygote L and non-homozygote L were separately observed. All observations were significant for unadjusted and adjusted analysis, except for COMT and TS. In thin/normal-weight women (BMI <25 kg/m2), the same effects of CYP17 genotypes on DHEA were observed as on the total cohort. CYP17 and COMT genes showed some direct influence on bone density. Mean percent change in T-BMD was negative for CYP17 non-homozygote A2 in contrast to a positive value for homozygote A2. Mean percent change in R-BMD showed the difference between COMT homozygote L and non-homozygote L with a larger decrease for the homozygote L. Together, CYP17 and COMT genotypes might have some effect on bone both directly and indirectly through their effects on endogenous sex steroids in postmenopausal Japanese women.