Capacity of endogenous sex steroids to predict bone loss in Japanese men: 10-year follow-up of the Taiji Cohort Study

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

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

Deficiency in androgens and upregulation of insulin-like growth factor-1 are involved in high bone turnover in men receiving androgen deprivation therapy for prostate cancer

OBJECTIVE

This study was performed to elucidate the mechanism of high bone turnover during androgen deprivation therapy (ADT) in terms of osteogenic endocrine activity by testosterone, adrenal androgens, and insulin-like growth factor-1 (IGF-I), and to identify markers reflecting the bone mineral density (BMD) during ADT.

DESIGN

BMD and samples of blood and urine were studied before and after 6months of ADT in 70 patients with localized prostate cancer.

RESULTS

Before ADT, serum free-testosterone, dehydroepiandrosterone sulfate (DHEA-S), androstenedione, and IGF-I levels were correlated with BMD (rs=0.344, p=0.004; rs=0.264, p=0.027; rs=0.329, p=0.005; rs=0.300, p=0.012, respectively). The serum IGF-I level was independently correlated with the pretreatment BMD (Multivariate p=0.001). These relationships disappeared after ADT (p=0.519, 0.316, 0.116, and 0.597, respectively). After ADT, serum levels of free-testosterone decreased (7.9 to 0.2pg/mL), and DHEA-S and androstenedione were also reduced (3.6 to 2.3μmol/L and 5.6 to 2.9nmol/L, respectively) (p<0.001 in all). In contrast, IGF-I levels were elevated after ADT by 11.6% (19.9 to 22.3nmol/L, p<0.001). Delta-values of IGF-I (post- minus pretreatment levels, mean: +2.2, ranged between -7.1 and +15.3) were inversely correlated with the pretreatment (rs=-0.333 p=0.005) and post-treatment (rs=-0.408, p=0.001) BMD. After ADT, the serum IGF-I level was closely correlated with the serum level of the bone formation marker bone-specific alkaline phosphatase (BAP) (rs=0.328, p=0.006), and delta-IGF-I and delta-BAP showed a close positive correlation (rs=0.388, p=0.001). The post-treatment BMD was correlated only with the urine deoxypyridinoline (DPD) concentration (rs=-0.302, p=0.024) among the bone formation/resorption markers including serum/urine N-telopeptide.

CONCLUSIONS

Serum IGF-I levels increased during ADT in men with a low BMD. Coupled with reduced androgen levels, elevated IGF-I levels, which were positively correlated with BAP during ADT, possibly explain the mechanism of ADT-related high bone turnover. The increase of IGF-I is more prominent in men whose BMD is already low at the baseline, and urine DPD might be a marker that reflects BMD during ADT.

PTH level but not 25 (OH) vitamin D level predicts bone loss rates in the elderly

We assessed the impact of calciotropic hormones on bone loss in 195 elderly subjects. After a median follow up of 4 years, parathyroid hormone (PTH) correlated negatively with changes in bone mineral density (BMD) at all skeletal sites. After adjustment for potential predictors of bone loss in the elderly, PTH level alone explained 3% of the variance in BMD changes at the hip.

INTRODUCTION

This study assessed the impact of calciotropic hormones on bone loss rates in an elderly population-based cohort of 195 ambulatory men and women, aged 65-85 years and followed up for a median of 4 years.

METHODS

Calcium intake, serum calcium, and phosphorus were assessed at baseline. Serum creatinine was measured at follow up visit. The 25 (OH) vitamin D [25-OHD] and PTH were measured at baseline and at follow up. Bone mass at the lumbar spine, hip, forearm and total body, as well as body composition was measured at baseline and at follow up by dual energy X-ray absorptiometry.

RESULTS

Mean 25-OHD level was 14.7 ± 6.4 ng/ml and mean PTH level was 47.9 ± 30.4 pg/ml. Age correlated negatively with percent changes in BMD at all skeletal sites (p < 0.05). Changes in body mass index (BMI) and in body composition correlated positively with BMD changes at all sites, except at the forearm. There was no correlation between 25-OHD and changes in BMD except at the trochanter (r = 0.19, p < 0.008). Conversely, PTH negatively correlated with changes in BMD at all skeletal sites (r = -0.14 to -0.27, p < 0.05). This correlation persisted after adjustment for age, changes in BMI, changes in fat mass and lean mass, serum creatinine, calcium intake, and 25-OHD levels. PTH level alone explained 3% of the variance in BMD changes at all hip subregions.

CONCLUSIONS

Serum PTH, but not 25-OHD, predicted bone loss rates in the elderly. Thus, it is important to normalize PTH level when correcting hypovitaminosis D in the elderly.