The relationship between sex steroids, bone turnover and vertebral fracture prevalence in asymptomatic men

Understanding the characteristics of idiopathic osteoporosis by a systematic review and meta-analysis

PURPOSE

To understand the pathophysiology of idiopathic osteoporosis (IOP) better, we conducted a systematic review and meta-analysis of bone mineral density (BMD), hormones, and bone turnover markers (BTMs) between IOP patients and healthy controls.

METHODS

Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, an appropriate search query was created, and three databases, including PubMed, ScienceDirect, and Google Scholar, were searched for screening relevant original articles. Feasible information, both qualitative and quantitative, was extracted and used to conduct meta-analyses. Publication bias and heterogeneity among studies were evaluated using appropriate statistical tools.

RESULTS

A total of 21 studies were included in the meta-analysis. There was reduced BMD at the lumbar spine (LS) (pooled: SDM: -2.38, p-value: 0.0001), femoral neck (FN) (pooled: SDM: -1.75 p-value: 0.0001), total hip (TH) (pooled: SDM: -1.825, p-value: 0.0001) and distal radius (DR) (pooled: SDM of -0.476, p-value: 0.0001), of which LS was the most affected site. There was no significant change in BTMs compared with healthy controls. Total estradiol (SDM: -1.357, p-value: 0.003) was reduced, and parathyroid hormone (PTH) (SDM: 1.51, p-value: 0.03) and sex hormone-binding globulin (SHBG) (SDM: 1.454, p-value: 0.0001) were elevated in IOP patients compared with healthy controls.

CONCLUSION

Our meta-analysis, the first of its kind on IOP, defines it as showing BMD decline maximally at LS compared with healthy controls without any alterations in the BTMs. Further studies are required to understand gender differences and the significance of altered hormonal profiles in this condition.

Bone health in ageing men

Osteoporosis does not only affect postmenopausal women, but also ageing men. The burden of disease is projected to increase with higher life expectancy both in females and males. Importantly, osteoporotic men remain more often undiagnosed and untreated compared to women. Sex steroid deficiency is associated with bone loss and increased fracture risk, and circulating sex steroid levels have been shown to be associated both with bone mineral density and fracture risk in elderly men. However, in contrast to postmenopausal osteoporosis, the contribution of relatively small decrease of circulating sex steroid concentrations in the ageing male to the development of osteoporosis and related fractures, is probably only minor. In this review we provide several clinical and preclinical arguments in favor of a 'bone threshold' for occurrence of hypogonadal osteoporosis, corresponding to a grade of sex steroid deficiency that in general will not occur in many elderly men. Testosterone replacement therapy has been shown to increase bone mineral density in men, however data in osteoporotic ageing males are scarce, and evidence on fracture risk reduction is lacking. We conclude that testosterone replacement therapy should not be used as a sole bone-specific treatment in osteoporotic elderly men.

Reduced trabecular bone mineral density and thinner cortices in men with distal forearm fractures

Men with distal forearm fractures have reduced bone density, an increased risk of osteoporosis and of further fractures. The aim of the study was to investigate the structural determinants of these observations using quantitative CT (qCT). Ninety six men with low-trauma distal forearm fracture and 101 age-matched healthy control subjects were recruited. All subjects underwent a quantitative CT on a standard 64-slice whole body CT scanner. These were analysed on Mindways QCT PRO™ Software to generate volumetric and geometric data at the lumbar spine, femoral neck and total hip, ultra-distal and distal 33 % radius. Biochemical investigations, health questionnaires and measurements of bone turnover were made. Men with fracture had significantly lower total and trabecular vBMD at all sites. The greatest percentage reduction was at the ultra-distal radius (13.5 % total and 11.7 % trabecular vBMD). In the fracture group cortical vBMD was significantly higher in the femoral neck (p < 0.001) and maintained at the ultra-distal radius compared with control subjects. However, cortical cross-sectional area (CSA) and thickness were significantly reduced at the femoral neck (p < 0.001 and p = 0.002 respectively) and forearm sites (CSA ultradistal radius p = 0.001, cortical thickness p = 0.002, CSA distal one third radius p = 0.045 and cortical thickness p = 0.005). Cross sectional moment of inertia (CSMI) and section moduli were significantly reduced at the femoral neck (CSMI1 p = 0.002, CSMI2 p = 0.012 and section moduli Z1 p < 0.001, Z2 p = 0.004) and the ultra-distal radius (CSMI1 p = 0.008 and section moduli Z1 p = 0.018, Z2 p = 0.007). In stepwise logistic regression analysis distal forearm fracture showed the strongest association with a model comprising ultra-distal forearm trabecular vBMD (negative), procollagen type I N-terminal propeptide (PINP, positive) and sex hormone binding globulin (SHBG, negative). In conclusion, these observations explain the structural reasons for the increased fracture risk in men with distal forearm fractures.

Bone turnover markers as determinants of bone density and fracture in men with distal forearm fractures: the pathogenesis examined in the Mr F study

The pathogenesis for low-trauma wrist fractures in men is not fully understood. This study found that these men had evidence of significantly higher bone turnover compared with control subjects. Bone turnover markers were negative predictors of bone mineral density and were a predictor of fracture.

INTRODUCTION

Men with distal forearm fractures have reduced bone density, an increased risk of osteoporosis and of further fractures. The aim of this study was to investigate whether or not men with distal forearm fractures had evidence of altered bone turnover activity.

METHODS

Fifty eight men with low-trauma distal forearm fracture and 58 age-matched healthy control subjects were recruited. All subjects underwent a DXA scan of the forearm, both hips, and lumbar spine, biochemical investigations, and health questionnaires. Measurements of beta crosslaps (βCTX), procollagen type I N-terminal propeptide (PINP), sclerostin, Dickkopf-1 (Dkk1), and fibroblast growth factor 23 (FGF 23) were made.

RESULTS

Men with fracture had significantly higher PINP than controls at 39.2 ng/ml (SD 19.5) versus 33.4 ng/ml (SD13.1) (p<0.001). They also had significantly higher βCTX at 0.45 ng/ml (SD 0.21) versus 0.37 ng/ml (SD 0.17) (p= 0.037). Fracture subjects had significantly lower aBMD and PINP was a negative predictor of aBMD at the total hip and βCTX a negative predictor of forearm aBMD. Sclerostin was a positive predictor of aBMD at the lumbar spine and hip sites. Sex hormone binding globulin (SHBG) at 37nmol/L (SD 15.0) was lower in fracture cohort compared to 47.9 nmol/L (SD 19.2) (p=0.001) in control. Multiple regression revealed that the best model for prediction of fracture included SHBG, P1NP, and ultra-distal forearm aBMD. The likelihood of distal forearm fracture was decreased by 5.1% for each nmol/L increase in SHBH and by 1.4% for every mg/cm² increase in ultra-distal forearm aBMD, but increased by 6.1 % for every ng/ml increase in P1NP. Men in the highest quartile of PINP had a significantly greater likelihood of distal forearm fracture than those in the lowest quartile.

CONCLUSION

The fracture group had significantly higher PINP and βCTX compared with the control group, and these markers were negative predictors of aBMD at the total hip and forearm sites, respectively. Sclerostin was a positive predictor of the variance of spinal and hip aBMD. Likelihood of forearm fracture was best predicted by a combination of SHBG, PINP, and ultra-distal forearm aBMD. Findings of such cross-sectional data should be treated with caution, as longitudinal studies would be required to confirm or refute them.

Osteoporotic hip and vertebral fractures in the Arab region: a systematic review

Asia is projected to account for the largest proportion of the rising burden of osteoporotic fractures worldwide. Data from the Middle East is scarce. We performed a systematic review on the epidemiology of vertebral and hip osteoporotic fractures in 22 Arab League countries, using Scopus, PubMed, and Embase. We identified 67 relevant publications, 28 on hip and 39 on vertebral fractures. The mean age of patients was 70-74 years, female to male ratio 1.2:2.1. Age-standardized incidence rates, to the UN 2010 population, were 236 to 290/100,000 for women from Kuwait and Lebanon, lower in Morocco. Risk factors for hip fractures included lower BMD or BMI, taller stature, anxiolytics, and sleeping pills. Most patients were not tested nor treated. Mortality derived from retrospective studies ranged between 10 and 20% at 1 year, and between 25 and 30% at 2-3 years. Among 39 studies on vertebral fractures, 18 described prevalence of morphometric fractures. Excluding grade 1 fractures, 13.3-20.2% of women, mean age 58-74 years, had prevalent vertebral fractures, as did 10-14% of men, mean age 62-74 years. Risk factors included age, gender, smoking, multiparity, years since menopause, low BMD, bone markers, high sclerostin, low IgF1, hypovitaminosis D, abdominal aortic calcification score, and VDR polymorphisms. Vertebral fracture incidence in women from Saudi Arabia, mean age 61, was 6.2% at 5 years, including grade 1 fractures. Prospective population-based fracture registries, prevalence studies, predictive models, fracture outcomes, and fracture liaison services from Arab countries are still lacking today. They are the pillars to closing the care gap of this morbid disease.

ASSOCIATION BETWEEN LOW BONE MINERAL DENSITY, METABOLIC SYNDROME AND SEX STEROIDS DEFICIENCY IN MEN

Objective

To analyze the association between low bone mineral density (BMD), metabolic syndrome (MS) and sex hormones deficiency in men.

Methods

We included in this retrospective study 199 men with osteoporosis or osteopenia and 167 men with normal BMD as controls, aged between 55-85 years old. Patients' evaluation included: medical history and physical examination, X-ray of thoracic and lumbar spine, measuring BMD at hip and lumbar spine, serum glucose and lipid profile, serum levels of total testosterone (tT), free testosterone (fT) and estradiol (E2).

Results

The results revealed a significant association between low BMD and MS (p=0.011). Vertebral fractures were more frequently associated with MS (p=0.041). Patients with MS had lower vertebral BMD (p=0.037) and lower E2 levels (p=0.024) compared with those without MS. In men with MS, E2 deficiency can predict the value of vertebral and hip BMD. fT deficiency can predict only the value of hip BMD.

Conclusions

A significant association between MS, low BMD, vertebral fractures and sex steroids deficiency, in particular E2 and fT was found. The presence of MS and sex hormones deficit can predict the reduction of BMD.

Sex hormones, sex hormone binding globulin, and vertebral fractures in older men

The association between sex hormones and sex hormone binding globin (SHBG) with vertebral fractures in men is not well studied. In these analyses, we determined whether sex hormones and SHBG were associated with greater likelihood of vertebral fractures in a prospective cohort study of community dwelling older men. We included data from participants in MrOS who had been randomly selected for hormone measurement (N=1463, including 1054 with follow-up data 4.6years later). Major outcomes included prevalent vertebral fracture (semi-quantitative grade≥2, N=140, 9.6%) and new or worsening vertebral fracture (change in SQ grade≥1, N=55, 5.2%). Odds ratios per SD decrease in sex hormones and per SD increase in SHBG were estimated with logistic regression adjusted for potentially confounding factors, including age, bone mineral density, and other sex hormones. Higher SHBG was associated with a greater likelihood of prevalent vertebral fractures (OR: 1.38 per SD increase, 95% CI: 1.11, 1.72). Total estradiol analyzed as a continuous variable was not associated with prevalent vertebral fractures (OR per SD decrease: 0.86, 95% CI: 0.68 to 1.10). Men with total estradiol values ≤17pg/ml had a borderline higher likelihood of prevalent fracture than men with higher values (OR: 1.46, 95% CI: 0.99, 2.16). There was no association between total testosterone and prevalent fracture. In longitudinal analyses, SHBG (OR: 1.42 per SD increase, 95% CI: 1.03, 1.95) was associated with new or worsening vertebral fracture, but there was no association with total estradiol or total testosterone. In conclusion, higher SHBG (but not testosterone or estradiol) is an independent risk factor for vertebral fractures in older men.

Sex hormone-binding globulin (SHBG) as an independent determinant of bone mineral density (BMD) among Chinese middle-aged and elderly men

The aim of the study was to assess the impact of sex hormone-binding globulin (SHBG) on bone mineral density (BMD) and bone turnover among Chinese middle-aged and elderly men. This cross-sectional study was carried out among 404 Chinese men aged over 45 years. BMD was measured with dual-energy X-ray absorptiometry, and participants' blood was collected for bone-specific alkaline phosphates (BSAP), SHBG and testosterone assay. Osteoporotic men had lower free testosterone (FT) and higher levels of SHBG, and BSAP than the osteopenia and normal groups. When SHBG levels were divided into quartiles, FT levels decreased and prevalence of osteoporosis increased with higher SHBG levels. Compared with subjects in the lowest quartile of SHBG levels (<36.55 nmol/l), subjects in the third quartile [OR (95 % CI) 2.998 (1.460-6.157), p = 0.002] and the highest quartile [OR (95 % CI) 4.439 (2.192-8.991), p < 0.001] were more likely to suffer with osteoporosis. FT was significantly positive related to total hip BMD and total lumbar BMD, whereas there was no association between TT and BMD after adjusting for age, BMI and FT. SHBG levels were also inversely related to BMD. SHBG could explain 1.4-2.1 % of the BMD variance after adjustment for age, BMI and FT. No association was found between BSAP and SHBG, TT and FT. Logistic regression analysis showed that BMI, smoking and FT or SHBG was independently associated with the presence of osteoporosis. Serum FT levels were positively correlated with BMD, while SHBG levels were inversely related to BMD. Increasing SHBG level was an independent risk factor for osteoporosis among Chinese men.

Obesity and fracture in men and women: an epidemiologic perspective

In Western societies, mean body weight has increased dramatically in older people, and a similar trend exists in Asia. Yet insufficient attention has been directed to the problem of osteoporotic fractures in the overweight and obese. Many, if not most, osteoporotic fractures occur in overweight or obese people, and obese men may be particularly susceptible. We discuss the potential implications of these findings, including the challenge of identifying individuals at highest risk, screening and treatment strategies, and future research directions.