The association between fat and lean mass and bone mineral density: the Healthy Twin Study

Impact of high fat and low lean mass phenotype on bone mineral content: A cross-sectional study of Chinese adolescent population

BACKGROUND AND OBJECTIVE

Research on body composition phenotypes and bone health in adolescents is limited. Hence, this study aimed to analyze the relationship between different body composition phenotypes, bone mineral content, and bone metabolism markers in Chinese adolescents.

METHODS

In this cross-sectional study, 1852 adolescents aged 12 to 18 years were selected from six schools in Yinchuan City between 2017 and 2020 using stratified cluster random sampling. The participant's body composition and bone mineral content (BMC) were measured using bioelectrical impedance analysis (BIA). Serum bone metabolic markers (OC, CTX, and Ca) were measured. Based on their FMI and LMI, individuals were categorized into four body composition phenotypes: low fat mass-low lean mass (LFMI-LLMI), low fat mass-high lean mass (LFMI-HLMI), high fat mass-high lean mass (HFMI-HLMI), high fat mass-low lean mass (HFMI-LLMI).

RESULTS

There was a statistically significant difference between the four different body composition phenotypes with BMC, CTX and Ca in boys (all P < 0.05), similar conclusions were found in girls, except the OC and CTX. After adjusting for age, gender, smoking, drinking, and others, compared with the LFMI-HLMI reference group, the two high FMI groups (HFMI-LLMI and HFMI-HLMI) had a greater negative correlation with BMC, while the low BMC risk of the HFMI-LLMI group was the highest (OR = 33.28; 95%CI: 11.12-99.63; P < 0.001). The correlation between BMC of different body composition phenotypes in boys was greater than that in girls. HFMI-HLMI is a risk phenotype negatively associated with Ca content (β = -0.12; 95%CI: -0.19 to -0.04; P < 0.05). Regardless of body composition level, BMC was always negatively correlated with fat mass (LLMI: β = -0.27; 95%CI: -0.32-0.21; HLMI: β = -0.52, 95%CI: -0.65-0.40) and positively correlated with lean mass (LFMI: β =0.24; 95%CI: 0.20-0.28; HFMI: β =0.23, 95%CI:0.13-0.33) (all P < 0.001). The fat mass showed different correlations with OC and CTX in girls and boys based on LLMI or HLMI (all P < 0.05).

CONCLUSION

HFMI-LLMI is a risk phenotype of low BMC in Chinese adolescents, and the relationship between fat mass and bone metabolism markers is affected by lean body mass and gender.

Association Between Sarcopenia and Fracture Risk in a Population From the UK Biobank Database

Studies on the fracture risk in presarcopenic and sarcopenic patients report contradictory results. The objective was to assess whether presarcopenia and sarcopenia are associated with an increase in fracture risk. We conducted a retrospective study using the UK Biobank cohort and the European Working Group on Sarcopenia in Older People 2 (EWGSOP2) criteria. Muscle strength was evaluated using hand-grip strength (HGS) and muscle mass using the skeletal muscle index (SMI; from bioimpedance analysis). Presarcopenia was defined through the two definitions available in the literature, as low HGS with normal SMI and as normal HGS with low SMI, and sarcopenia as low HGS and low SMI. Fracture events were recorded as "fracture" (location compatible with an osteoporotic origin) and "major osteoporotic fracture" (MOF), as listed in the FRAX tool. Associations were assessed using Cox proportional hazards models, adjusted for sarcopenia and osteoporosis risk factors. Adjusted hazard ratios (HRa ) and their 95% confidence intervals (CI) were reported. A total of 387,025 participants (women 54.4%; median age 58.0 years; interquartile range [IQR] 51.0-63.0 years) were included. At baseline, there were 18,257 (4.7%) presarcopenic participants-subgroup 1 (low HGS only), 7940 (2.1%) presarcopenic participants-subgroup 2 (low SMI only), and 1124 (0.3%) sarcopenic participants. Over a median follow-up of 12.0 years (IQR 11.4-12.6 years), 18,300 (4.7%) participants were diagnosed with at least one incident fracture. Presarcopenic (subgroups 1 and 2) and sarcopenic status were significantly associated with a higher risk of fracture (respectively adjusted HRs: HR = 1.26 [1.19-1.33], HR = 1.20 [1.11-1.30], HR = 1.30 [1.08-1.56]) and with a higher risk of MOF (respectively adjusted HRs: HR = 1.30 [1.21-1.40], HR = 1.19 [1.08-1.72], HR = 1.18 [0.93-1.49]). In a middle-aged population, the fracture and MOF risks were higher in both presarcopenic and sarcopenic participants compared with nonsarcopenic participants. © 2023 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).

Body composition phenotypes and bone health in young adults: A cluster analysis

BACKGROUND AND AIMS

Lean mass is considered the best predictor of bone mass, as it is an excellent marker of bone mechanical stimulation, and changes in lean mass are highly correlated with bone outcomes in young adults. The aim of this study was to use cluster analysis to examine phenotype categories of body composition assessed by lean and fat mass in young adults and to assess how these body composition categories are associated with bone health outcomes.

METHODS

Cluster cross-sectional analyses of data from 719 young adults (526 women) aged 18-30 years from Cuenca and Toledo, Spain, were conducted. Lean mass index (lean mass (kg)/height (m)2), fat mass index (fat mass (kg)/height (m)2), bone mineral content (BMC) and areal bone mineral density (aBMD) were assessed by dual-energy X-ray absorptiometry.

RESULTS

A cluster analysis of lean mass and fat mass index z scores resulted in a classification of a five-category cluster solution that could be interpreted according to the body composition phenotypes of individuals as follows: high adiposity-high lean mass (n = 98), average adiposity-high lean mass (n = 113), high adiposity-average lean mass (n = 213), low adiposity-average lean mass (n = 142), and average adiposity-low lean mass (n = 153). ANCOVA models showed that individuals in clusters with a higher lean mass had significantly better bone health (z score: 0.764, se: 0.090) than their peers in other cluster categories (z score: -0.529, se: 0.074) after controlling for sex, age, and cardiorespiratory fitness (p < 0.05). Additionally, subjects belonging to the categories with a similar average lean mass index but with high or low-adiposity levels (z score: 0.289, se: 0.111; z score: 0.086, se: 0.076) showed better bone outcomes when the fat mass index was higher (p < 0.05).

CONCLUSIONS

This study confirms the validity of a body composition model using a cluster analysis to classify young adults according to their lean mass and fat mass indices. In addition, this model reinforces the main role of lean mass on bone health in this population and that in phenotypes with high-average lean mass, factors associated with fat mass may also have a positive effect on bone status.

Sarcopenia and osteosarcopenia among patients undergoing hemodialysis

Background

Sarcopenia and osteoporosis are closely interconnected and associated with adverse health outcomes. Osteosarcopenia is the concurrent presence of the two conditions and has rarely been reported in hemodialysis patients. Whether hemodialysis patients with osteosarcopenia are at greater risk of mortality than those with either condition alone remains unknown. The aim of this study was to explore the prevalence of sarcopenia and its association with osteoporosis and to determine its impact on survival risk in hemodialysis patients.

Methods

A total of 209 adults undergoing hemodialysis were enrolled from the dialysis center in the West China Hospital of Sichuan University, and our study was registered at the Chinese Clinical Trial Register (number: ChiCTR2100043932). Muscle mass, handgrip strength, bone mineral density (BMD), and biochemical parameters were assessed. All deaths were recorded during a follow-up of 35.15 ± 15.37 months.

Results

Seventy-eight patients were diagnosed with sarcopenia, with a prevalence of 37.3%. After adjustment for potential confounders, age (OR=1.094, P <0.001), female sex (OR= 3.44, P =0.005), diabetes (OR=3.756, P =0.008), CRP (OR=1.09, P =0.015), serum magnesium (OR=0.755, p=0.042) and BMI (OR=0.701, P <0.001) were independently associated with sarcopenia. Among the 209 patients, 103 patients completed the BMD assessment. The prevalence of osteosarcopenia was 22.3%, while 20.4% of participants had sarcopenia alone and 12.6% had osteoporosis alone. The proportions of patients who died were 13.0% for nonsarcopenia&nonosteoporosis, 15.4% for osteoporosis alone, 47.6% for sarcopenia alone, and 52.2% for osteosarcopenia. Cox regression analysis showed that osteosarcopenia was independently associated with all-cause mortality (HR=3.74, 95% CI: 1.172-11.938), while osteoporosis alone and sarcopenia alone were not.

Conclusion

Patients undergoing hemodialysis had a high incidence of sarcopenia and osteosarcopenia, muscle mass and strength showed a significant association with BMD, and osteosarcopenia might have a powerful impact on mortality in those patients.

Clinical trial registration

http://www.chictr.org.cn/, identifier ChiCTR2100043932.

Interaction Effect of Phase Angle and Age on Femoral Neck Bone Mineral Density in Patients with Non-Dialysis Chronic Kidney Disease Stage 5

Background: Low bone mass is common in malnourished patients with chronic kidney disease (CKD) and can lead to a higher risk of fractures. Elderly and CKD patients have the same risk factors for protein-energy wasting, sarcopenia, and osteoporosis. Here, we investigated the association between phase angle (PhA) and bone mineral density (BMD) in dialysis-naïve patients with CKD stage 5 (CKD5) and identified a statistical relationship between PhA and age, which affects bone density. Methods: Bio-impedance spectroscopy for evaluating body composition and PhA and dual-energy X-ray absorptiometry for determining the BMD were simultaneously performed in 167 consecutive patients (mean age, 59.65 ± 13.98 years; women, 40.1%). Two-way analysis of variance (ANOVA) was conducted to assess the potential interaction effect of PhA and age on femoral neck BMD (FN-BMD). Results: Our results showed that PhA and age were independently associated with FN-BMD and T-score in multiple linear regressions analyses. A significant interaction effect of PhA and age on FN-BMD was found on two-way ANOVA (p = 0.028). The average BMD values for the first and second tertiles of the PhA were higher in the young versus elderly group, whereas patients in the elderly group had higher BMD in the third tertiles. Conclusions: A relationship was noted between PhA and BMD in patients with advanced-stage CKD. The effect of PhA level on FN-BMD differed between elderly and young patients. Our study suggested that higher PhA levels could be a marker explaining the maintenance of good bone health in elderly patients with CKD5. Further longitudinal analyses are needed to determine whether PhA predicts the risk of CKD-MBD-related fractures during CKD progression.

Menopause-Related Changes in Body Composition Are Associated With Subsequent Bone Mineral Density and Fractures: Study of Women's Health Across the Nation

During the menopause transition (MT), lean mass decreases and fat mass increases. We examined the associations of these body composition changes during the MT (2 years before to 2 years after the final menstrual period) with bone mineral density (BMD) at the end of the MT and fracture after the MT. We included 539 participants from the Study of Women's Health Across the Nation who were not taking bone-beneficial or bone-detrimental medications before or during the MT. Using multivariable linear regression, we assessed the independent associations of % lean mass loss and % fat mass gain during the MT (mutually adjusted) with femoral neck (FN) and lumbar spine (LS) BMD at the end of the MT, adjusted for pre-MT BMD, pre-MT lean and fat mass, race/ethnicity, Study of Women's Health Across the Nation (SWAN) study site, age, and cigarette use. We used Cox proportional hazards regression to quantify the relations of % lean loss and % fat gain during the MT with fracture after the MT. The Cox model was adjusted for the covariates above plus post-MT use of bone-detrimental medications, and censored at the first use of bone-beneficial medications; we further controlled for FN or LS BMD at the end of the MT. Adjusted for covariates, each standard deviation (SD) (6.9%) increment in lean mass loss was associated with 0.010 g/cm2 lower FN BMD (p < 0.0001); each SD (19.9%) increment in fat mass gain was related to 0.026 g/cm2 greater FN (p = 0.009) and LS (p = 0.03) BMD. Each SD increment in lean mass loss and fat mass gain was associated with 63% (p = 0.001) and 28% (p = 0.05) greater fracture hazard after the MT; associations were essentially unchanged by BMD adjustment. MT-related lean mass loss and fat mass gain were associated differentially with BMD; both were independently related to more fractures. Mitigating MT-related body composition changes may reduce fracture risk. © 2022 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).

Risk Factors Associated with Bone Marrow Adiposity Deposition in Postmenopausal Women in the CASH China Study

Purpose

To investigated the factors that influence BMAC.

Patients and Methods

Quantitative computed tomography (QCT) and magnetic resonance imaging (MRI) were applied to measure abdominal fat areas, liver fat content, erector muscle fat content, and BMAC of the L2-4 vertebrae. Sex hormone, adipokine, and inflammatory factor levels were measured on the same day.

Results

Although age, erector muscle fat content, estradiol, testosterone, and adiponectin/leptin levels showed correlations with BMAC in the correlation analysis, the equations obtained from the whole population by multivariate analysis were unclear. Patients were stratified according to BMAC quartiles, and differences were found in vBMD, age, estradiol, testosterone, and erector muscle fat content among the four quartiles. Logistic analyses confirmed that age, estradiol/testosterone ratio, and TNF-α had independent effects on BMAC in all quartiles. In addition, height was related to higher BMAC quartiles, and glucose was related to lower BMAC quartiles.

Conclusion

Compared to other body fats, BMAC is a unique fat depot. Age, estradiol/testosterone ratio, and TNF-α are all key influencing factors related to BMAC in postmenopausal women. Furthermore, height and glucose levels were related to BMAC in the higher and lower BMAC quartiles, respectively.

Associations between paraspinal muscles fatty infiltration and lumbar vertebral bone mineral density - An investigation by fast kVp switching dual-energy CT and QCT

Purpose

To investigate the relationship between paraspinal muscles fat content and lumbar bone mineral density (BMD).

Methods

A total of 119 participants were enrolled in our study (60 males, age: 50.88 ± 17.79 years, BMI: 22.80 ± 3.80 kg·m^-2; 59 females, age: 49.41 ± 17.69 years, BMI: 22.22 ± 3.12 kg·m^-2). Fat content of paraspinal muscles (erector spinae (ES), multifidus (MS), and psoas (PS)) were measured at (ES L1/2-L4/5; MS L2/3-L5/S1; PS L2/3-L5/S1) levels using dual-energy computed tomography (DECT). Quantitative computed tomography (QCT) was used to assess BMD of L1 and L2. Linear regression analysis was used to assess the relationship between BMD of the lumbar spine and paraspinal muscles fat content with age, sex, and BMI. The variance inflation factor (VIF) was used to detect the degree of multicollinearity among the variables. P < .05 was considered to indicate a statistically significant difference.

Results

The paraspinal muscles fat content had a fairly significant inverse association with lumbar BMD after controlling for age, sex, and BMI (adjusted R ² = 0.584-0.630, all P < .05).

Conclusion

Paraspinal muscles fat content was negatively associated with BMD.Paraspinal muscles fatty infiltration may be considered as a potential marker to identify BMD loss.

Computed Tomography Measured Psoas Cross Sectional Area Is Associated With Bone Mineral Density Measured by Dual Energy X-Ray Absorptiometry

Dual-energy X-ray absorptiometry (DEXA) is the gold standard for osteoporosis screening and diagnosis. However, abdominal conventional computed tomography (CT) scan is widely available and multiple studies validated its use as a screening tool for osteoporosis compared to DEXA. The aim of this study was to determine the reliability of measuring core muscle size at the L3-L4 intervertebral disk space and estimate the relationship between core muscle size and bone mineral density (BMD) measured by DEXA. Retrospective chart review was performed on patients who underwent a DEXA scan for osteoporosis and a conventional abdominal CT scan within one-year apart. Total cross-sectional area (CSA) and Hounsfield Unit (HU) density of core muscles (psoas, paraspinal, and abdominal wall muscles) were measured. The association between psoas, paraspinal, abdominal, and central muscle CSA and Bone Mineral density (BMD) at L3, L4, total Lumbar Spine (LS), and right (R) and left (L) hip was estimated in crude and adjusted for age and sex linear regression models. Sixty patients (37 females, 23 males) met the inclusion criteria. The average interval between DEXA and abdominal CT scans was 3.6 months (range 0.1-10.2). Psoas muscle density was significantly positively associated with R hip BMD in both crude and adjusted models (β = 20.2, p = 0.03; β = 18.5, p = 0.01). We found a significant positive linear association between psoas muscle CSA and HU density with BMD of LS, R, and L hip in both crude and adjusted models. The strongest significant positive linear association was observed between total abdominal CSA and R hip BMD in crude and age and sex adjusted (ß = 85.3, p = 0.01; ß = 63.9, p = 0.02, respectively). CT scans obtained for various clinical indications can provide valuable information regarding BMD. This is the first study investigating association between BMD with central muscle density and CSA, and it demonstrated their significant positive the association.

TwinEQTL: Ultra Fast and Powerful Association Analysis for eQTL and GWAS in Twin Studies

We develop a computationally efficient alternative, TwinEQTL, to a linear mixed-effects model (LMM) for twin genome-wide association study (GWAS) data. Instead of analyzing all twin samples together with LMM, TwinEQTL first splits twin samples into two independent groups on which multiple linear regression analysis can be validly performed separately, followed by an appropriate meta-analysis-like approach to combine the two non-independent test results. Through mathematical derivations, we prove the validity of TwinEQTL algorithm and show that the correlation between two dependent test statistics at each single-nucleotide polymorphism (SNP) are independent of its minor allele frequency (MAF). Thus the correlation is constant across all SNPs. Through simulations, we show empirically that TwinEQTL has well controlled type I error with negligible power loss compared to the gold-standard linear mixed effects models. To accommodate eQTL analysis with twin subjects, we further implement TwinEQTL into a R package with much improved computational efficiency. Our approaches provide a significant leap in terms of computing speed for GWAS and eQTL analysis with twin samples.

CT ‐based Stiffness Measures of Trabecular Bone Microstructure — Cadaveric Validation and In Vivo Application

Osteoporosis causes bone fragility and elevates fracture risk. Applications of finite element (FE) analysis (FEA) for assessment of trabecular bone (Tb) microstructural strength at whole‐body computed tomography (CT) imaging are limited due to challenges with Tb microstructural segmentation. We present a nonlinear FEA method for distal tibia CT scans evading binary segmentation of Tb microstructure, while accounting for bone microstructural distribution. First, the tibial axis in a CT scan was aligned with the FE loading axis. FE cubic mesh elements were modeled using image voxels, and CT intensity values were calibrated to ash density defining mechanical properties at individual elements. For FEA of an upright volume of interest (VOI), the bottom surface was fixed, and a constant displacement was applied at each vertex on the top surface simulating different loading conditions. The method was implemented and optimized using the ANSYS software. CT‐derived computational modulus values were repeat scan reproducible (intraclass correlation coefficient [ICC] ≥ 0.97) and highly correlated (r ≥ 0.86) with the micro‐CT (μCT)‐derived values. FEA‐derived von Mises stresses over the segmented Tb microregion were significantly higher (p < 1 × 10⁻¹¹) than that over the marrow space. In vivo results showed that both shear and compressive modulus for males were higher (p < 0.01) than for females. Effect sizes for different modulus measures between males and females were moderate‐to‐high (≥0.55) and reduced to small‐to‐negligible (<0.40) when adjusted for pure lean mass. Among body size and composition attributes, pure lean mass and height showed highest (r ∈ [0.45 0.56]) and lowest (r ∈ [0.25 0.39]) linear correlation, respectively, with FE‐derived modulus measures. In summary, CT‐based nonlinear FEA provides an effective surrogate measure of Tb microstructural stiffness, and the relaxation of binary segmentation will extend the scope for FEA in human studies using in vivo imaging at relatively low‐resolution. © 2022 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.

A review of menopause nomenclature

Menopause nomenclature varies in the scholarly literature making synthesis and interpretation of research findings difficult. Therefore, the present study aimed to review and discuss critical developments in menopause nomenclature; determine the level of heterogeneity amongst menopause definitions and compare them with the Stages of Reproductive Aging Workshop criteria. Definitions/criteria used to characterise premenopausal and postmenopausal status were extracted from 210 studies and 128 of these studies were included in the final analyses. The main findings were that 39.84% of included studies were consistent with STRAW classification of premenopause, whereas 70.31% were consistent with STRAW classification of postmenopause. Surprisingly, major inconsistencies relating to premenopause definition were due to a total lack of reporting of any definitions/criteria for premenopause (39.84% of studies). In contrast, only 20.31% did not report definitions/criteria for postmenopause. The present findings indicate that there is a significant amount of heterogeneity associated with the definition of premenopause, compared with postmenopause. We propose three key suggestions/recommendations, which can be distilled from these findings. Firstly, premenopause should be transparently operationalised and reported. Secondly, as a minimum requirement, regular menstruation should be defined as the number of menstrual cycles in a period of at least 3 months. Finally, the utility of introducing normative age-ranges as supplementary criterion for defining stages of reproductive ageing should be considered. The use of consistent terminology in research will enhance our capacity to compare results from different studies and more effectively investigate issues related to women's health and ageing.

The associations between body fat distribution and bone mineral density in the Oxford Biobank: a cross sectional study

BACKGROUND

Body composition is associated with bone mineral density (BMD), but the precise associations between body fat distribution and BMD remain unclear. The regional adipose tissue depots have different metabolic profiles. We hypothesized that they would have independent associations with BMD.

RESEARCH DESIGN AND METHODS

We used data from 4,900 healthy individuals aged 30-50 years old from the Oxford Biobank to analyze associations between regional fat mass, lean mass and total BMD.

RESULTS

Total lean mass was strongly positively associated with BMD. An increase in total BMD was observed with increasing mass of all the fat depots, as measured either by anthropometry or DXA, when accounting for lean mass. However, on adjustment for both total fat mass and lean mass, fat depot specific associations emerged. Increased android and visceral adipose tissue mass in men, and increased visceral adipose tissue mass in women, were associated with lower BMD.

CONCLUSIONS

Fat distribution alters the association between adiposity and BMD.

The Inverse Association of Leg Fat Mass and Osteoporosis in Individuals with Type 2 Diabetes Independent of Lean Mass

PURPOSE

Recent studies revealed that high levels of thigh fat were independently associated with better glucose and lipid metabolism, as well as lower risk of hypertension and cardiometabolic disease. Therefore, the purpose of this study was to evaluate the association between leg fat mass (FM) and osteoporosis (OP) in individuals with type 2 diabetes (T2DM).

PATIENTS AND METHODS

In this cross-sectional study, a total of 1,259 individuals aged 50 years or older with T2DM (female 536, male 723) were included. A bioelectrical impedance analyser was used to assess the segment body composition containing FM and lean mass (LM) of arms, legs, and trunk. Bone mineral density (BMD) was determined by dual-energy X-ray absorptiometry.

RESULTS

Leg FM was positively correlated with BMD of all sites in females and BMD of femoral neck and total hip in males after adjusting age, diabetes duration, glucose and lipid metabolism indexes, and lifestyle (all P<0.05). LM was positively associated with BMD at almost sites (P<0.001), while leg FM/LM ratio had no relationship with BMD at any skeleton sites (P>0.05). Compared with the bottom tertile group of leg FM, the risk of OP was significantly lower in the top tertile group both in females (T3 vs T1: OR=0.206, 95% CI=0.098-0.433, P<0.001) and males (T3 vs T1: OR=0.385, 95% CI=0.182-0.815, P<0.05), even after adjusting for LM.

CONCLUSION

In the present study, higher leg FM was correlated with the lower risk of OP in both men and postmenopausal women with T2DM independently of total LM.

Body composition and osteoporotic fracture using anthropometric prediction equations to assess muscle and fat masses

BACKGROUND

Obesity is protective of bone health; however, abdominal obesity is associated with a higher fracture risk. Little is known about whether body composition protects or adversely affects osteoporotic fractures because of practical issues regarding assessment tools. This study aimed to evaluate the association of predicted body composition with fracture risk to determine the distinctive and differing effects of muscle or fat mass on bone health outcomes in the general population.

METHODS

This population-based, longitudinal cohort study used 2009-2010 Korean National Health Insurance Service data and follow-up data from 1 January 2011 to 31 December 2013, to determine the incidence of osteoporotic fracture (total, spine, and non-spine) defined using the International Classification of Diseases, Tenth Revision codes. The study participants were aged ≥50 years (men, 158 426; women, 131 587). The predicted lean body mass index (pLBMI), appendicular skeletal muscle index (pASMI), and body fat mass index (pBFMI) were used to assess body composition, using anthropometric prediction equations.

RESULTS

Over a 3 year follow-up, we identified 2350 and 6175 fractures in men and women, respectively. The mean age of the participants was 60.2 ± 8.3 and 60.7 ± 8.4 years in men and women, respectively. In a multivariable-adjusted Cox proportional hazards regression model, increasing pLBMI or pASMI was significantly associated with a decreased risk of total fractures in men and women. When comparing individuals in the lowest pLBMI and pASMI (reference groups), men with the highest pLBMI and pASMI had adjusted hazard ratios of 0.63 [95% confidence interval (CI) 0.47-0.83] and 0.62 (95% CI 0.47-0.82), and women with the highest pLBMI and pASMI had adjusted hazard ratios of 0.72 (95% CI 0.60-0.85) and 0.71 (95% CI 0.60-0.85), respectively, for total fractures. The pBFMI had no significant association with total fractures in men or women. Regarding sex-specific or site-specific differences, the protective effects of the pLBMI and pASMI on fractures were greater in men and reduced the risk of spinal fractures. An increased pBFMI was associated with an increased risk of spinal fractures in women.

CONCLUSIONS

An increased pLBMI or pASMI was significantly associated with decreased total osteoporotic fracture risk; however, the pBFMI showed no statistically significant association. Muscle mass was more important than fat mass in preventing future osteoporotic fractures based on anthropometric prediction equations.

Three pleiotropic loci associated with bone mineral density and lean body mass

Both bone mineral density (BMD) and lean body mass (LBM) are important physiological measures with strong genetic determination. Besides, BMD and LBM might have common genetic factors. Aiming to identify pleiotropic genomic loci underlying BMD and LBM, we performed bivariate genome-wide association study meta-analyses of femoral neck bone mineral density and LBM at arms and legs, and replicated in the large-scale UK Biobank cohort sample. Combining the results from discovery meta-analysis and replication sample, we identified three genomic loci at the genome-wide significance level (p < 5.0 × 10-8): 2p23.2 (lead SNP rs4477866, discovery p = 3.47 × 10-8, replication p = 1.03 × 10-4), 16q12.2 (rs1421085, discovery p = 2.04 × 10-9, replication p = 6.47 × 10-14) and 18q21.32 (rs11152213, discovery p = 3.47 × 10-8, replication p = 6.69 × 10-6). Our findings not only provide useful insights into lean mass and bone mass development, but also enhance our understanding of the potential genetic correlation between BMD and LBM.

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.

Are the Relationships of Lean Mass and Fat Mass With Bone Microarchitecture Causal or Due to Familial Confounders? A Novel Study of Adult Female Twin Pairs

It is not known whether the relationships of lean mass (LM) and fat mass (FM) with bone microarchitecture and geometry are causal and/or are because of confounders, including familial confounders arising from genetic and environment effects shared by relatives. We tested the hypotheses that: (i) LM is associated with cortical bone traits, (ii) FM is associated with trabecular bone traits, and (iii) these relationships of LM and FM with bone microarchitecture and geometry have a causal component. Total body composition was quantified for 98 monozygotic (MZ) and 54 dizygotic (DZ) white female twin pairs aged 31 to 77 years. Microarchitecture at the distal tibia and distal radius was quantified using HRpQCT and StrAx software. We applied the Inference about Causation through Examination of FAmiliaL CONfounding (ICE FALCON) method. Within‐individuals, distal tibia total bone area, cortical area, cortical thickness, and trabecular number were positively associated with LM (standardized regression coefficient (β) = 0.13 to 0.43; all p < 0.05); porosity of the inner transitional zone (ITZ) was negatively associated with LM (β = −0.22; p < 0.01). Trabecular number was positively associated with FM (β = 0.40; p < 0.001), and trabecular thickness was negatively associated with FM (β = −0.27; p < 0.001). For porosity of ITZ and trabecular number, the cross‐pair cross‐trait association with LM was significant before and after adjustment for the within‐individual association with LM (all ps < 0.05). For trabecular number, the cross‐pair cross‐trait association with FM was significant before and after adjustment for the within‐individual association with FM (p < 0.01). There were no significant changes in these cross‐pair cross‐trait associations after adjustment for the within‐individual association (p = 0.06 to 0.99). Similar results were found for distal radius measures. We conclude that there was no evidence that the relationships of LM and FM with bone microarchitecture and geometry are causal; they must in part due to by familial confounders affecting both bone architecture and body composition. © 2020 The Authors. JBMR Plus published by Wiley Periodicals LLC. on behalf of American Society for Bone and Mineral Research.

Bone Mineral Density of Femur and Lumbar and the Relation between Fat Mass and Lean Mass of Adolescents: Based on Korea National Health and Nutrition Examination Survey (KNHNES) from 2008 to 2011

It is most important to reach the maximum bone density in the childhood period to prevent developing osteoporosis; it is widely known that increased body weight has a positive correlation with bone density and that even though both the fat mass and lean mass have a significant impact on bone density, the latter mass has more importance for adults. Therefore, the study analyzed to identify the relationship between bone density and both fat mass and lean mass of Korean adolescents. Subjects were chosen among 21,303 people from the Korea National Health and Nutrition Examination Survey (KNHNES) between 2008 and 2011 that took a bone density checkup; as a result, 1454 teenagers aged between 12 and 18 were selected. Data analysis was performed in SAS ver. 9.4 (SAS Institute Inc., Cary, NC, USA) following the KNHNES and the weighted complex sample analysis was conducted; body fat mass and lean mass were divided into quintile groups, and to figure out the differences in bone density that were analyzed in six models adjusted by body weight (kg) and walking (yes/no), muscle strengthening exercises (yes/no), nutrition (intake of ca (g), and serum vitamin D (ng/mL)). Then, the generalized linear model (GLM) and trend test were conducted for each gender with a significance level of 0.05. The bone density differences of fat mass and lean mass were analyzed. The result of Model 6 considering all correction variables is as follows; in the case of male adolescents, the total femur and lumbar spine showed a significant difference (F = 13.120, p < 0.001; F = 12.900, p < 0.001) for fat mass, and the trend test showed that the figures significantly decreased (β = −0.030, p < 0.001; −0.035, p < 0.001). Meanwhile, for lean mass, the total femur and lumbar spine had a significant difference (F = 16.740, p < 0.001; F = 20.590, p < 0.001) too, but the trend test showed a significant increase (β = 0.054, p < 0.001; 0.057, p < 0.001). In the case of female adolescents, the lumbar spine (F = 3.600, p < 0.05) for lean mass showed a significant difference, and it also significantly rose in the trend test too (β = 0.020, p < 0.01). To sum up the results, for male adolescents, the bone density differences for fat mass (FM) and lean mass (LM) all had significant differences, but for female adolescents, only the lumbar spine for LM showed such a result. Meanwhile, both genders showed that LM had a more positive impact on bone density than FM.

Determinants of Bone Health Status in a Multi-Ethnic Population in Klang Valley, Malaysia

Background and objectives: Studies on osteoporosis risk factors are limited in Malaysia, so this study assesses the factors associated with bone health assessed using dual-energy X-ray absorptiometry (DXA) among Malaysians aged ≥40 years. Subjects and Methods: Data on demography, medical history, dietary and lifestyle practices of 786 Malaysians (51.4% women) aged ≥40 years recruited in Klang Valley were obtained. Their body composition and bone health were determined using DXA. The association between risk factors and bone health status was assessed using binary logistic regression. Results: The prevalence of suboptimal bone health and osteoporosis was higher in women (59.4% and 16.1%) than men (40.8% and 8.4%). Overall, the predictors of suboptimal bone health and osteoporosis among the subjects were increased age and higher fat mass. Lower monthly income was positively associated with osteoporosis. Being menopausal was a risk factor for both suboptimal bone health and osteoporosis in women. Women with no formal education were more likely to get osteoporosis. Being a smoker and Chinese were positively related to suboptimal bone health among men. Meanwhile, predictors of osteoporosis among men were regular alcohol and dairy product consumption, higher fat mass and having a tertiary education. Conclusions: This study calls for immediate and effective interventions for middle-aged and elderly populations with risk factors to halt the progression of bone loss.

Bone Health and its Relation to Energy Intake, Fat Mass and its Distribution

BACKGROUND AND OBJECTIVES

Osteoporosis and obesity are two of the most important inter-related diseases worldwide. This study aimed to investigate impact of fat mass and its distribution on bone health in relation to energy intake among sample of Egyptian women.

MATERIALS AND METHODS

A cross-sectional study included 116 Egyptian women with age range 25-65 years old. They were classified according to the menopause into 2 groups: Pre-menopausal (n = 51) and post menopausal (n = 65). All participants have undergone anthropometric measurements, body composition, DEXA and laboratory investigations.

RESULTS

Among overweight/obese women, pre-menopausal women had significant higher values of BMR and BMD at both lumbar spines, neck of femur and significant lower values of central obesity (waist/hip ratio, waist/height ratio, visceral fat) and C-terminal peptides than postmenopausal ones. Among pre and post-menopausal women, BMD at both sites had significant positive correlations with obesity markers (BMI, waist and hip circumferences), fat mass, BMR, in addition to fat distribution, visceral fat, leptin among pre-menopausal women and C-terminal peptide among postmenopausal women. Among pre-menopausal women, BMR significantly explained 56% of the variations in BMD at neck of femur, while at lumbar spines the best model was BMI, BMR and waist circumference, which significantly explain 33% of the variations in BMD.

CONCLUSION

Bone health positively correlated with BMI, fat mass and its distribution and BMR, particularly at femur neck, among pre and post-menopausal Egyptian women. Overweight/obesity can be considered as a protective factor for bone health.

Fat mass changes during menopause: a metaanalysis

OBJECTIVE

Data: Fat mass has been shown to increase in aging women; however, the extent to which menopausal status mediates these changes remains unclear. The purpose of this review was to determine (1) how fat mass differs in quantity and distribution between premenopausal and postmenopausal women, (2) whether and how age and/or menopausal status moderates any observed differences, and (3) which type of fat mass measure is best suited to the detection of differences in fat mass between groups.

STUDY

This review with metaanalyses is reported according to Metaanalysis of Observational Studies in Epidemiology guidelines.

STUDY APPRAISAL AND SYNTHESIS METHODS

Studies (published up to May 2018) were identified via PubMed to provide fat mass measures in premenopausal and postmenopausal women. We included 201 cross-sectional studies in the metaanalysis, which provided a combined sample size of 1,049,919 individuals and consisted of 478,734 premenopausal women and 571,185 postmenopausal women. Eleven longitudinal studies were included in the metaanalyses, which provided a combined sample size of 2472 women who were premenopausal at baseline and postmenopausal at follow up.

RESULTS

The main findings of this review were that fat mass significantly increased between premenopausal and postmenopausal women across most measures, which included body mass index (1.14 kg/m²; 95% confidence interval, 0.95-1.32 kg/m²), bodyweight (1 kg; 95% confidence interval, 0.44-1.57 kg), body fat percentage (2.88%; 95% confidence interval, 2.13-3.63%), waist circumference (4.63 cm; 95% confidence interval, 3.90-5.35 cm), hip circumference (2.01 cm; 95% confidence interval, 1.36-2.65 cm), waist-hip ratio (0.04; 95% confidence interval, 0.03-0.05), visceral fat (26.90 cm²; 95% confidence interval, 13.12-40.68), and trunk fat percentage (5.49%; 95% confidence interval, 3.91-7.06 cm²). The exception was total leg fat percentage, which significantly decreased (-3.19%; 95% confidence interval, -5.98 to -0.41%). No interactive effects were observed between menopausal status and age across all fat mass measures.

CONCLUSION

The change in fat mass quantity between premenopausal and postmenopausal women was attributable predominantly to increasing age; menopause had no significant additional influence. However, the decrease in total leg fat percentage and increase in measures of central fat are indicative of a possible change in fat mass distribution after menopause. These changes are likely to, at least in part, be due to hormonal shifts that occur during midlife when women have a higher androgen (ie, testosterone) to estradiol ratio after menopause, which has been linked to enhanced central adiposity deposition. Evidently, these findings suggest attention should be paid to the accumulation of central fat after menopause, whereas increases in total fat mass should be monitored consistently across the lifespan.

Impact of Weight Loss With Intragastric Balloon on Bone Density and Microstructure in Obese Adults

The historical concept that obesity protects against bone fractures has been questioned. Weight loss appears to reduce bone mineral density (BMD); however, the results in young adults are inconsistent, and data on the effects of weight loss on bone microstructure are limited. This study aimed to evaluate the impact of weight loss using an intragastric balloon (IGB) on bone density and microstructure. Forty obese patients with metabolic syndrome (mean age 35.1 ± 7.3 yr) used an IGB continuously for 6 mo. Laboratory tests, areal BMD, and body composition measurements via dual-energy X-ray absorptiometry, and volumetric BMD and bone microstructure measurements via high-resolution peripheral quantitative computed tomography were conducted before IGB placement and after IGB removal. The mean weight loss was 11.5%. After 6 mo, there were significant increases in vitamin D and carboxyterminal telopeptide of type 1 collagen levels. After IGB use, areal BMD increased in the spine but decreased in the total femur and the 33% radius. Cortical BMD increased in the distal radius but tended to decrease in the distal tibia. The observed trabecular bone loss in the distal tibia contributed to the decline in the total volumetric BMD at this site. There was a negative correlation between the changes in leptin levels and the measures of trabecular quality in the tibia on high-resolutionperipheral quantitative computed tomography. Weight loss may negatively impact bone microstructure in young patients, especially for weight-bearing bones, in which obesity has a more prominent effect.

[Osteosarcopenia: A narrative review]

Osteosarcopenia is a phenotype resulting from the combination of sarcopenia and low bone mineral density. Based on the relationship between bone and muscle, this phenotype is associated with a higher risk of falls, fractures, dependence, and health care costs than its individual components. Given its characteristics, it can be considered as a new geriatric syndrome. Therefore, understanding its pathophysiology and diagnosis, as well as its non-pharmacological and pharmacological management is a task of great importance. The problem in addressing this phenotype arises from the tradition of managing sarcopenia and osteoporosis separately. There is also a lack of consensus on what to call it (sarco-osteopenia, sarco-osteoporosis, osteosarcopenia). The aim of this review is to outline the epidemiology, pathophysiology, diagnoses, adverse events, and management of osteosarcopenia.

Fat and Lean Mass Predict Bone Mass During Energy Restriction in Sedentary and Exercising Rodents

Energy restriction (ER) causes bone loss, but the impact of exercise during ER is less understood. In this study, we examined the impact of metabolic hormones and body composition on both total body bone mineral content (BMC) and local (proximal tibia) volumetric bone mineral density (vBMD) during short- (4 weeks) and long-term (12 weeks) ER with and without exercise in adult female rats. Our first goal was to balance energy between sedentary and exercising groups to determine the impact of exercise during ER. Second, we aimed to determine the strongest predictors of bone outcomes during ER with energy-matched exercising groups.

Methods: Female Sprague–Dawley rats were divided into three sedentary groups (ad libitum, –20% ER, and –40% ER) and three exercising groups (ad libitum, –10% ER, and –30% ER). Approximately a 10% increase in energy expenditure was achieved via moderate treadmill running (∼60–100 min 4 days/week) in EX groups. n per group = 25–35. Data were analyzed as a 2 × 3 ANOVA with multiple linear regression to predict bone mass outcomes.

Results: At 4 weeks, fat and lean mass and serum insulin-like growth factor-I (IGF-I) predicted total body BMC (R² = 0.538). Fat mass decreased with ER at all levels, while lean mass was not altered. Serum IGF-I declined in the most severe ER groups (–40 and –30%). At 12 weeks, only fat and lean mass predicted total body BMC (R² = 0.718). Fat mass declined with ER level regardless of exercise status and lean mass increased due to exercise (+5.6–6.7% vs. energy-matched sedentary groups). At the same time point, BMC declined with ER, but increased with exercise (+7.0–12.5% vs. energy-matched sedentary groups). None of our models predicted vBMD at the proximal tibia at either time point.

Conclusion: Both fat and lean mass statistically predicted total body BMC during both short- and long-term ER. Fat and lean mass decreased with ER, while lean mass increased with EX at each energy level. Measures that predicted total body skeletal changes did not predict site-specific changes. These data highlight the importance of maintaining lean mass through exercise during periods of ER.

Associations Between Lean Mass, Muscle Strength and Power, and Skeletal Size, Density and Strength in Older Men

Studies examining the relationship between muscle parameters and bone strength have not included multiple muscle measurements and/or both central and peripheral skeletal parameters. The purpose of this study was to explore the relationship between lean mass, muscle strength and power, and skeletal size, bone density, and bone strength. We studied the association between appendicular lean mass (ALM), grip strength, and leg power, and central quantitative computed tomography (QCT) parameters in 2857 men aged 65 years or older; peripheral QCT was available on a subset (n = 786). ALM, grip strength, and leg power were measured by dual-energy X-ray absorptiometry (DXA), Jamar dynamometer, and the Nottingham Power Rig, respectively. Multivariable models adjusting for potential confounders including age, race, study site, BMI, and muscle measurements were developed and least squares means were generated from linear regression models. For the multivariable model, percent differences of bone parameters between lowest (Q1) and highest quartiles (Q4) of ALM, grip strength, and leg power were reported. ALM was significantly associated with central and peripheral QCT parameters: percent higher values (Q4 versus Q1) ranging from 3.3% (cortical volumetric bone mineral density [vBMD] of the femoral neck) to 31% (vertebral strength index of the spine). Grip strength was only significantly associated with radial parameters: percent higher values (Q4 versus Q1) ranging from 2.5% (periosteal circumference) to 7.5% (33% axial strength index [SSIx]). Leg power was associated with vertebral strength and lower cross-sectional area with percent lower values (Q4 versus Q1) of -11.9% and -2.7%, respectively. In older men, stronger associations were observed for ALM compared to muscle strength and power. Longitudinal studies are needed to examine the relationship between independent changes in muscle measurements and skeletal size, density and strength. © 2018 American Society for Bone and Mineral Research.

Impact of cross-sex hormone therapy on bone mineral density and body composition in transwomen

OBJECTIVE

Cross-sex hormone therapy (CSHT) has been associated with changes in bone and lean/fat mass. This study assessed bone mineral density (BMD), appendicular lean mass (ALM), and total fat mass in transwomen undergoing CSHT.

PATIENTS AND DESIGN

We evaluated 142 transwomen (mean age: 33.7 ± 10.3 years; BMI: 25.4 ± 4.6; 86.6% with previous CSHT) during the first 3 months of regular oestrogen treatment (with or without anti-androgens). A reference group including 22 men and 17 cis women was also studied.

MEASUREMENTS

Clinical and hormonal evaluation and dual-energy X-ray absorptiometry (DXA).

RESULTS

Bone mineral density was similar in trans and reference women, and lower at all sites in transwomen vs men. Low bone mass for age was observed in 18% of transwomen at baseline vs none of the reference women or men. Appendicular lean mass and total fat mass were positively correlated with L1-L4 BMD, explaining 14.9% of the observed variation in lumbar spine BMD and 20.6% of the variation in total femur BMD. Appendicular lean mass was similar in trans and reference women, and lower in transwomen vs men. Total fat mass was lower in trans vs reference women. Densitometry was repeated after a mean of 31.3 ± 6.5 months in 46 transwomen. There was a significant increase in total fat mass and a significant decrease in ALM. Bone mineral density remained stable over time.

CONCLUSIONS

The fairly high prevalence of low bone mass in this sample of transwomen from southern Brazil seems to be related to lower ALM. Non-pharmacological lifestyle-related strategies for preventing bone loss could be beneficial for transgender women receiving long-term CSHT.

Epicardial Fat Thickness and Bone Mineral Content: The Healthy Twin Study in Korea

Background

The conventional concept of positive association between general obesity and bone health was challenged in recent studies reporting the different effects of specific fat deposition on bone health. In the present study, we investigated the association between epicardial fat and bone health.

Methods

We measured echocardiographic epicardial fat thickness (EFT) and bone mineral content (BMC) in a twin-family cohort of Koreans (n = 1,198; 525 men, 460 pre- and 213 post-menopausal women). A total 121 pairs of monozygotic twin (MZ) and 404 pairs of dizygotic twin and sibling pairs (DZ/Sib) were included.

Results

EFT was positively associated with BMC in total, as well as in three subgroups (β = 0.107, 0.076, and 0.058 for men, pre-, and post-menopausal women, respectively). The positive association between EFT and BMC remained for DZ/Sib difference analysis, but was absent for MZ comparisons. The positive association between BMI and BMC was consistent for DZ/Sib and MZ difference analysis. After adjusting for the effect of general obesity via BMI, the association between BMC and EFT was statistically non-significant (β = 0.020, 0.000, and −0.009 for men, pre-, and post-menopausal women, respectively).

Conclusion

Our findings do not support epicardial fat’s beneficial effects on bone health, whereas general adiposity has an osteotropic effect. The association between EFT and BMC is through common genetic component factors.

The Association between Fat Mass, Lean Mass and Bone Mineral Density in Premenopausal Women in Korea: A Cross-Sectional Study

Background

We investigated the association between body composition, especially truncal or non-truncal fat mass (FM), and bone mineral density (BMD) in premenopausal women in Korea.

Methods

A cross-sectional study was performed using data from the Korea National Health and Nutrition Examination Survey IV and V (2008–2011). Total lean mass (LM), total FM (TFM), truncal FM, and non-truncal FM, and BMD of the total femur, femoral neck (FN), and lumbar spine were measured using dual-energy X-ray absorptiometry. The association between body composition and BMD was analyzed using multiple linear regression. The risk of low BMD according to quartiles of TFM, truncal FM, and non-truncal FM was calculated using logistic regression. Subgroup analysis according to body mass index was also performed.

Results

In 4,343 premenopausal women, total LM was positively associated with BMD regardless of weight adjustment. TFM, truncal FM, and non-truncal FM were inversely associated with BMD after adjusting for weight. Odds ratios (ORs) for low BMD and 95% confidence intervals (CIs) of the highest quartile of TFM, truncal FM, and non-truncal FM compared with the lowest quartile were calculated. The risk of low BMD of the FN was higher in the highest quartile of TFM (OR, 4.48; 95% CI, 1.11–18.01) and truncal FM (OR, 5.48; 95% CI, 1.75–17.20). Truncal FM and not-truncal FM had an inverse association with BMD in the non-obese and obese subgroups of women.

Conclusion

Total LM has a protective effect on BMD and FM can have a detrimental effect on BMD besides its skeletal loading effect.

Soluble activin receptor type IIB decoy receptor differentially impacts murine osteogenesis imperfecta muscle function

INTRODUCTION

Osteogenesis imperfecta (OI) is characterized by skeletal fragility and muscle weakness. In this study we investigated the effects of soluble activin type IIB receptor (sActRIIB-mFc) on muscle mass and function in 2 distinct mouse models of OI: osteogenesis imperfecta murine (oim) and +/G610C.

METHODS

Wild-type (WT), +/G610C, and oim/oim mice were treated from 2 to 4 months of age with Tris-buffered saline (vehicle) or sActRIIB-mFc and their hindlimb muscles evaluated for mass, morphology, and contractile function.

RESULTS

sActRIIB-mFc-treated WT, +/G610C, and oim/oim mice had increased hindlimb muscle weights and myofiber cross-sectional area compared with vehicle-treated counterparts. sActRIIB-mFc-treated oim/oim mice also exhibited increased contractile function relative to vehicle-treated counterparts.

DISCUSSION

Blocking endogenous ActRIIB was effective at increasing muscle size in mouse models of OI, and increasing contractile function in oim/oim mice. ActRIIB inhibitors may provide a potential mutation-specific therapeutic option for compromised muscle function in OI. Muscle Nerve 57: 294-304, 2018.

Appendicular and whole body lean mass outcomes are associated with finite element analysis-derived bone strength at the distal radius and tibia in adults aged 40years and older

PURPOSE

The purpose of this cross-sectional study was to determine how appendicular lean mass index (ALMI), and whole body lean (LMI) and fat mass indices (FMI) associate with estimated bone strength outcomes at the distal radius and tibia in adults aged 40 years and older.

METHODS

Dual energy X-ray absorptiometry (DXA) scans were performed to determine body composition, including whole body lean and fat mass, and appendicular lean mass. ALMI (appendicular lean mass/height²), LMI (lean tissue mass/height²) and FMI (fat mass/height²) were calculated. High-resolution peripheral quantitative computed tomography (HRpQCT) scans were performed to assess bone structural properties at the distal radius and tibia. Using finite element analysis, failure load (N), stiffness (N/mm), ultimate stress (MPa), and cortical-to-trabecular load ratio were estimated from HRpQCT scans. The associations between body composition (ALMI, LMI, FMI) and estimated bone strength were examined using bivariate and multivariable linear regression analyses adjusting for age, sex, and other confounding variables.

RESULTS

In 197 participants (127 women; mean±SD, age: 69.5±10.3y, body mass index: 27.95±4.95kg/m², ALMI: 7.31±1.31kg/m²), ALMI and LMI were significantly associated with failure load at the distal radius and tibia (explained 39%-48% of the variance) and remained significant after adjusting for confounding variables and multiple testing (R²=0.586-0.645, p<0.001). ALMI, LMI, and FMI did not have significant associations with ultimate stress in our multivariable models. FMI was significantly associated with cortical-to-trabecular load ratio at the distal radius and tibia (explained 6%-12% of the variance) and remained significant after adjusting for confounders and multiple testing (R²=0.208-0.243, p<0.001). FMI was no longer significantly associated with failure load after adjusting for confounders.

CONCLUSION

These findings suggest that ALMI and LMI are important determinants of estimated bone strength, particularly failure load, at the distal radius and tibia, and may contribute to preservation of bone strength in middle-to-late adulthood.

The relationship between osteoporosis and body composition in pre- and postmenopausal women from different ethnic groups in China

OBJECTIVE

To investigate the ethnic differences in osteoporosis (OP) and body composition (BC) and their relationship in the Maonan, Mulam, Hmong, and Yao minorities in China.

DESIGN

A total of 860 Maonan, Mulam, Hmong, and Yao women were included in this cross-sectional study. Demographic, health history, and lifestyle information was collected using questionnaires. BC was measured through bioelectrical impedance analysis, and bone mineral density (BMD) was assessed via calcaneal quantitative ultrasound.

RESULTS

Compared with premenopausal women, postmenopausal women exhibited a lower fat-free mass (FFM), muscle mass (MM), limb muscle mass, and T-score but a higher waist-to-hip ratio and prevalence of OP in each minority (p < .05). After adjustment for age, Hmong women displayed the highest body mass index, fat mass, percentage of body fat, visceral fat, and subcutaneous fat contents, while Yao women presented the highest T-scores and lowest prevalence of OP among the four minorities (p < .05). Having a greater number of children and an older age were significant risk factors for OP in all ethnic groups (p < .05, OR > 1). In addition, our results revealed that FFM and MM exhibited exactly the same weak positive relationship with the T-score (r = 0.081, p < .05) after adjusting for menopausal status and age in all of the participants. Furthermore, significant ethnic differences in the relationship between BC and the T-score existed in the four minorities studied here.

CONCLUSIONS

BC and OP prevalence varied by menopausal status and ethnic group, and ethnic-specific relationships between BC and BMD were present in the four minorities. More research is needed to further investigate the ethnic differences in BC, OP, and risk factors for lower BMD to develop targeted prevention strategies to reduce the burden of OP across different ethnic groups in China.

Bone Variables in Active Overweight/Obese Men and Sedentary Overweight/Obese Men

The aim of this study was to compare bone variables in active overweight/obese men and sedentary overweight/obese men. Thirty-seven active overweight/obese men and 45 sedentary overweight/obese men participated in this study. Weight and height were measured, and body mass index was calculated. Body composition and bone variables (bone mineral content [BMC], bone mineral density [BMD], geometric indices of hip bone strength, and trabecular bone score) were measured by DXA. Physical activity level, daily calcium intake, daily protein intake, and sleep duration were measured by validated questionnaires. Maximum oxygen consumption (VO₂ max) was determined by direct measurement while exercising on a medical treadmill. One-repetition-maximum half-squat of the lower limbs was measured using a validated protocol. Body weight and body mass index were higher in sedentary overweight/obese men than in active overweight/obese men. In the whole population (n = 82), VO₂ max (in liter per minute), lean mass, and one-repetition-maximum half-squat were positively correlated to BMC, BMD, and geometric indices of hip bone strength (cross-sectional area and section modulus [Z] of the femoral neck [FN]). After adjusting for body weight using a 1-way analysis of covariance, active overweight/obese men displayed higher whole-body BMC, lumbar spine BMD, total hip BMD, FN BMD, FN cross-sectional area, and FN Z values than sedentary overweight/obese men. In conclusion, the current study suggests that physical activity level positively affects bone variables in overweight/obese men. Optimizing lean mass and muscular strength of the lower limbs can help to prevent osteoporosis in overweight and obese men.

Association between Lumbar Bone Mineral Density and Carotid Intima-Media Thickness in Korean Adults: a Cross-sectional Study of Healthy Twin Study

Bone mineral density (BMD) has been suggested to be associated with atherosclerosis. In the present study, we evaluated the association between lumbar BMD and the segments of carotid intima-media thickness (CIMT), a surrogate marker of subclinical atherosclerosis, in Korean adults, with consideration of sex and menopause status. Among 1,679 Korean adults who enrolled in a Healthy Twin Study, 723 men, 690 premenopausal women, and 266 postmenopausal women measured the CIMT at the common carotid artery intima-media thickness (CCA-IMT), carotid bifurcation intima-media thickness (BIF-IMT), internal carotid artery intima-media thickness (ICA-IMT) using B-mode ultrasound and lumbar BMD using dual-energy X-ray absorptiometry. The composite CIMT was calculated as the mean value of three CIMTs. The association was evaluated using linear mixed models. In premenopausal women, lumbar BMD was positively associated with composite CIMT and with CCA-IMT (P = 0.008 and 0.002, respectively). However, no association was observed between BMD and CIMT in men or in postmenopausal women. Stratified analysis revealed the effect of body mass index (BMI) on the association between BMD and CIME. The positive association in premenopausal women persisted only in low BMI (< 25 kg/m²) group, whereas a positive association appeared at high BMI (≥ 25 kg/m²) group in men. A high lumbar BMD may indicate an elevated risk of subclinical atherosclerosis in premenopausal women and men with high BMI.

Bone Mineral Density and Body Composition are Associated with Circulating Angiogenic Factors in Post-menopausal Women

Lean mass (LM) and fat mass (FM) are closely related to bone mass (BM) in post-menopausal women, although their relative importance is unclear. Angiogenic factors which control angiogenesis may influence BM, LM and FM. The aim of the study was to compare the contribution of LM and FM to bone mineral density (BMD) and the association between these tissues and circulating angiogenic factors. The study population comprised of 392 post-menopausal women aged mean [SD] 61.8 [6.4] years. BMD was measured at the lumbar spine (LS), neck of femur and total hip (TH) by dual-energy X-ray absorptiometry (DXA). DXA scan was also used to determine LM and FM. Angiopoietin-1 and 2 (ANG-1, ANG-2) were measured by sandwich enzyme-linked immunosorbent assay. Following adjustment for confounders, significant positive independent associations were seen between LM with BMD at all skeletal sites (TH: p < 0.0001) and FM with BMD at the hip sites (TH: p = 0.004). When BMD and LM were regressed against the angiogenic factors, positive associations were seen between ANG-2 with LM (p = 0.002) and LS BMD (p = 0.05). Negative associations were observed between the ratio of ANG-1/ANG-2 with LS BMD (p = 0.014), TH BMD (p = 0.049) and LM (p = 0.029). FM and fat distribution (android/gynoid fat ratio) were negatively associated with ANG-1 (p = 0.006) and ANG-2 (p = 0.004), respectively. ANG-1 and ANG-2 may be involved in the maintenance of bone, muscle and fat mass.

Relationship between Bone-Specific Physical Activity Scores and Measures for Body Composition and Bone Mineral Density in Healthy Young College Women

OBJECTIVE

The purpose of this cross-sectional study was to investigate the relationship between bone-specific physical activity (BPAQ) scores, body composition, and bone mineral density (BMD) in healthy young college women.

METHODS

Seventy-three college women (21.7 ± 1.8 years; 162.1 ± 4.6 cm; 53.9 ± 5.8 kg) between the ages of 19 and 26 years were recruited from the universities in Seoul and Gyeonggi province, South Korea. We used dual energy X-ray absorptiometry to measure the lumbar spine (L2-L4) and proximal femur BMD (left side; total hip, femoral neck). The BPAQ scores (past, pBPAQ; current, cBPAQ; total, tBPAQ) were used to obtain a comprehensive account of lifetime physical activity related to bone health. We used X-scan plus II instrumentation to measure height (cm), weight (kg), fat free mass (FFM, kg), percent body fat (%), and body mass index (BMI). Participants were asked to record their 24-hour food intake in a questionnaire.

RESULTS

There were positive correlations between BPAQ scores and total hip (pBPAQ r = 0.308, p = 0.008; tBPAQ, r = 0.286, p = 0.014) and FN BMD (pBPAQ r = 0.309, p = 0.008; tBPAQ, r = 0.311, p = 0.007), while no significant relationships were found in cBPAQ (p > 0.05). When FFM, Vitamin D intake, cBPAQ, pBPAQ, and tBPAQ were included in a stepwise multiple linear regression analysis, FFM and pBPAQ were predictors of total hip, accounting for 16% (p = 0.024), while FFM and tBPAQ predicted 14% of the variance in FN (p = 0.015). Only FFM predicted 15% of the variance in L2-L4 (p = 0.004). There was a positive correlation between Vitamin D intake and L2-L4 (p = 0.025), but other dietary intakes variables were not significant (p > 0.05).

CONCLUSIONS

BPAQ-derived physical activity scores and FFM were positively associated with total hip and FN BMD in healthy young college women. Our study suggests that osteoporosis awareness and effective bone healthy behaviors for college women are required to prevent serious bone diseases later in life.

Relationship of sarcopenia and body composition with osteoporosis

The purpose of the study is to investigate the relationship between sarcopenia and body composition and osteoporosis in cohorts of three different races with a total of 17,891 subjects. Lean mass and grip strength were positively associated with bone mineral densities (BMDs). Subjects with sarcopenia were two times more likely to have osteoporosis compared with normal subjects.

INTRODUCTION

The relationship between sarcopenia and osteoporosis is not totally clear. First, the present study assessed this relationship by using two different definitions for sarcopenia. Second, we examined the associations of body composition (including muscle mass as a major and important component) and muscle strength on regional and whole-body BMDs.

METHODS

In total, 17,891 subjects of African American, Caucasian, and Chinese ethnicities were analyzed. Sarcopenia was defined by relative appendicular skeletal muscle mass (RASM) cut points and also by the definition of the European Working Group on Sarcopenia in Older People (low RASM plus low muscle function). Multiple regression analyses were conducted to examine the association of fat mass, lean mass (including muscle mass), and grip strength with regional and whole-body BMDs. Multivariate logistic regression analysis was performed to explore the association between sarcopenia and osteopenia/osteoporosis.

RESULTS

BMDs were positively associated with lean mass and negatively associated with fat mass, after controlling for potential confounders. Grip strength was significantly associated with higher BMDs. Each standard deviation (SD) increase in RASM resulted in a ~37 % reduction in risk of osteopenia/osteoporosis (odds ratio (OR) = 0.63; 95 % confidence interval (CI) = 0.59, 0.66). Subjects with sarcopenia defined by RASM were two times more likely to have osteopenia/osteoporosis compared with the normal subjects (OR = 2.04; 95 % CI = 1.61, 2.60). Similarly, subjects with sarcopenia (low muscle mass and low grip strength) were ~1.8 times more likely to have osteopenia/osteoporosis than normal subjects (OR = 1.87; 95 % CI = 1.09, 3.20).

CONCLUSIONS

High lean mass and muscle strength were positively associated with BMDs. Sarcopenia is associated with low BMD and osteoporosis.

Lean mass and fat mass have differing associations with bone microarchitecture assessed by high resolution peripheral quantitative computed tomography in men and women from the Hertfordshire Cohort Study

Understanding the effects of muscle and fat on bone is increasingly important in the optimisation of bone health. We explored relationships between bone microarchitecture and body composition in older men and women from the Hertfordshire Cohort Study. 175 men and 167 women aged 72-81 years were studied. High resolution peripheral quantitative computed tomography (HRpQCT) images (voxel size 82 μm) were acquired from the non-dominant distal radius and tibia with a Scanco XtremeCT scanner. Standard morphological analysis was performed for assessment of macrostructure, densitometry, cortical porosity and trabecular microarchitecture. Body composition was assessed using dual energy X-ray absorptiometry (DXA) (Lunar Prodigy Advanced). Lean mass index (LMI) was calculated as lean mass divided by height squared and fat mass index (FMI) as fat mass divided by height squared. The mean (standard deviation) age in men and women was 76 (3) years. In univariate analyses, tibial cortical area (p<0.01), cortical thickness (p<0.05) and trabecular number (p<0.01) were positively associated with LMI and FMI in both men and women. After mutual adjustment, relationships between cortical area and thickness were only maintained with LMI [tibial cortical area, β (95% confidence interval (CI)): men 6.99 (3.97,10.01), women 3.59 (1.81,5.38)] whereas trabecular number and density were associated with FMI. Interactions by sex were found, including for the relationships of LMI with cortical area and FMI with trabecular area in both the radius and tibia (p<0.05). In conclusion, LMI and FMI appeared to show independent relationships with bone microarchitecture. Further studies are required to confirm the direction of causality and explore the mechanisms underlying these tissue-specific associations.

Contributions of fat mass and fat distribution to hip bone strength in healthy postmenopausal Chinese women

The fat and bone connection is complicated, and the effect of adipose tissue on hip bone strength remains unclear. The aim of this study was to clarify the relative contribution of body fat accumulation and fat distribution to the determination of proximal femur strength in healthy postmenopausal Chinese women. This cross-sectional study enrolled 528 healthy postmenopausal women without medication history or known diseases. Total lean mass (LM), appendicular LM (ALM), percentage of lean mass (PLM), total fat mass (FM), appendicular FM (AFM), percentage of body fat (PBF), android and gynoid fat amount, android-to-gynoid fat ratio (AOI), bone mineral density (BMD), and proximal femur geometry were measured by dual energy X-ray absorptiometry. Hip structure analysis was used to compute some variables as geometric strength-related parameters by analyzing the images of the hip generated from DXA scans. Correlation analyses among anthropometrics, variables of body composition and bone mass, and geometric indices of hip bone strength were performed with stepwise linear regression analyses as well as Pearson's correlation analysis. In univariate analysis, there were significantly inverse correlations between age, years since menopause (YSM), hip BMD, and hip geometric parameters. Bone data were positively related to height, body weight, LM, ALM, FM, AFM, and PBF but negatively related to AOI and amount of android fat (all P < 0.05). AFM and AOI were significantly related to most anthropometric parameters. AFM was positively associated with height, body weight, and BMI. AFM was negatively associated with age and YSM. AOI was negatively associated with height, body weight, and BMI. AOI positively associated with age and YSM. LM, ALM, and FM had a positive relationship with anthropometric parameters (P < 0.05 for all). PLM had a negative relationship with those parameters. The correlation between LM, ALM, FM, PLM, ALM, age, and YSM was not significant. In multivariate linear regression analysis, the hip bone strength was observed to have a consistent and unchanged positive association with AFM and a negative association with AOI, whereas its association with other variables of body composition was not significant after adjusting for age, years since menopause, height, body weight, and BMI. AFM may be a positively protective effect for hip bone strength while AOI, rather than android fat, shows a strong negative association with hip bone strength after making an adjustment for confounders (age, YSM, height, body weight, and BMI) in healthy postmenopausal Chinese women. Rational weight control and AOI reduction during menopause may have vital clinical significance in decreasing postmenopausal osteoporosis.

Risk of Nonspine Fractures in Older Adults with Sarcopenia, Low Bone Mass, or Both

OBJECTIVES

To test the hypothesis that men and women with low bone mineral density (BMD) and sarcopenia have a higher risk of fracture than those with only one or neither conditions.

DESIGN

The Osteoporotic Fractures in Men Study and the Study of Osteoporotic Fractures in women are prospective observational studies with a mean follow up of 9 (2000-2012) and 8 years (1997-2009), respectively.

SETTING

U.S. clinical centers.

PARTICIPANTS

Men (n = 5,544; mean age 73.7) and women (n = 1,114; mean age 77.6) aged 65 and older, able to walk without assistance, and without bilateral hip replacement.

MEASUREMENTS

Sarcopenia was defined as low appendicular lean mass plus slowness or weakness and low BMD according to the World Health Organization definition of a T-score less than -1.0. Participants were classified as having normal BMD and no sarcopenia (3,367 men, 308 women), sarcopenia only (79 men, 48 women), low BMD only (1,986 men, 626 women), and low BMD and sarcopenia (112 men, 132 women).

RESULTS

Men with low BMD and sarcopenia (hazard ratio (HR)=3.79, 95% confidence interval (CI)=2.65-5.41) and men with low BMD only (HR=1.67, 95% CI=1.45-1.93) but not men with sarcopenia only (HR=1.14, 95% CI=0.62-2.09) had greater risk of fracture than men with normal BMD and no sarcopenia. Women with low BMD and sarcopenia (HR=2.27, 95% CI=1.37-3.76) and women with low BMD alone (HR=2.62, 95% CI=1.74-3.95), but not women with only sarcopenia, had greater risk of fracture than women with normal BMD and no sarcopenia.

CONCLUSION

Men with low BMD and sarcopenia are at especially high risk of fracture. Sarcopenia alone did not increase fracture risk in either group.

Positive Association Between Adipose Tissue and Bone Stiffness

Obesity is often considered to have a protective effect against osteoporosis. On the other hand, several recent studies suggest that adipose tissue may have detrimental effects on bone quality. We therefore aimed to investigate the associations between body mass index (BMI), waist circumference (WC), visceral adipose tissue (VAT) or abdominal subcutaneous adipose tissue (SAT), and bone stiffness. The study involved 2685 German adults aged 20-79 years, who participated in either the second follow-up of the population-based Study of Health in Pomerania (SHIP-2) or the baseline examination of the SHIP-Trend cohort. VAT and abdominal SAT were quantified by magnetic resonance imaging. Bone stiffness was assessed by quantitative ultrasound (QUS) at the heel (Achilles InSight, GE Healthcare). The individual risk for osteoporotic fractures was determined based on the QUS-derived stiffness index and classified in low, medium, and high risk. Linear regression models, adjusted for sex, age, physical activity, smoking status, risky alcohol consumption, diabetes, and height (in models with VAT or abdominal SAT as exposure), revealed positive associations between BMI, WC, VAT or abdominal SAT, and the QUS variables broadband-ultrasound attenuation or stiffness index. Moreover, BMI was positively associated with speed of sound. Our study shows that all anthropometric measures including BMI and, WC as well as abdominal fat volume are positively associated with bone stiffness in the general population. As potential predictors of bone stiffness, VAT and abdominal SAT are not superior to easily available measures like BMI or WC.

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.

Lean Mass Appears to Be More Strongly Associated with Bone Health than Fat Mass in Urban Black South African Women

OBJECTIVES

To examine the association between body composition (fat mass, lean mass and body mass index, BMI) and bone health (bone mineral density, BMD and fracture risk) in urban black South African women.

DESIGN

A cross sectional study examining associations between body composition, dietary intake (food frequency questionnaire), habitual physical activity (Activity energy expenditure (AEE) measured using an accelerometer with combined heart rate monitor and physical activity questionnaire) and bone health (BMD using dual-energy X ray absorptiometry, DXA and fracture risk).

SETTING

Urban community dwellers from Ikageng in the North-West Province of South Africa.

PARTICIPANTS

One hundred and eighty nine (189) healthy postmenopausal women aged ≥43 years.

RESULTS

Fat mass and lean mass were significantly associated with BMD and fracture risk when adjusted for potential confounders. However, lean mass and not fat mass remained significantly associated with femoral neck BMD (β = 0.49, p <0.001), spine BMD (β = 0.48, p< 0.0001) and hip BMD (β = 0.59, p< 0.0001). Lean mass was also negatively associated with fracture risk (β = -0.19 p =0.04) when both lean and fat mass were in the same model.

CONCLUSION

Lean mass and fat mass were positively associated with femoral neck, spine and hip BMDs and negatively associated with fracture risk in urban black South African women. Our finding suggests that increasing lean mass rather than fat mass is beneficial to bone health. Our study emphasises the importance of positive lifestyle changes, intake of calcium from dairy and adequate weight to maintain and improve bone health of postmenopausal women.

Is FEV(1) an indicator of low bone mineral density in adults? The Fifth Korea National Health and Nutrition Examination Survey

The association between forced expiratory volume in 1 s (FEV1) and bone mineral density (BMD) is heterogeneous in population-based studies. This study aimed to investigate this relationship when sex and menopausal status in women, BMD sites, and anthropometric measures were taken into account. In 3,975 Koreans (1,783 men, 662 premenopausal women, 1,530 postmenopausal women, aged 40-91 years) participating in the Fifth Korea National Health and Nutrition Examination Survey in 2010-2011, this relationship for BMD at femur (total and neck) and lumbar spine was examined in each subgroup after adjusting for age, smoking, and alcohol habit, physical activity, calcium intake, osteoporosis treatment, and anthropometry (weight and height, height and BMI, or height, lean mass, and fat mass). Airflow limitation (FEV(1) ≥ 80, 50-80, and < 50% of predicted FEV(1)) and lower vs. higher BMD using BMD values at site and subgroup-specific 10 percentile of BMD distribution were defined. In multiple regression analysis, the association between FEV(1) and BMD was significant in premenopausal women [B = 0.027-0.031 (total femur), 0.035-0.037 (femoral neck), p < 0.05] but not in other subgroups. In logistic regression analysis, severe airflow limitation was associated with lower BMD in postmenopausal women [OR 2.21-2.37 (total femur), 2.25 (femoral neck), p < 0.05] and premenopausal women (OR 2.14, 95% CI, 1.01-4.50 for femoral neck in height and body composition-adjusted model), but not exhibit these associations in men. As a whole, the associations with spine BMD were non-significant. Therefore, the associations were sex-, menopausal status in women-, and BMD site-specific, while the types of anthropometry had similar effects on the associations.

Fast eQTL Analysis for Twin Studies

Twin data are commonly used for studying complex psychiatric disorders, and mixed effects models are one of the most popular tools for modeling dependence structures between twin pairs. However, for eQTL (expression quantitative trait loci) data where associations between thousands of transcripts and millions of single nucleotide polymorphisms need to be tested, mixed effects models are computationally inefficient and often impractical. In this paper, we propose a fast eQTL analysis approach for twin eQTL data where we randomly split twin pairs into two groups, so that within each group the samples are unrelated, and we then apply a multiple linear regression analysis separately to each group. A score statistic that automatically adjusts the (hidden) correlation between the two groups is constructed for combining the results from the two groups. The proposed method has well-controlled type I error. Compared to mixed effects models, the proposed method has similar power but drastically improved computational efficiency. We demonstrate the computational advantage of the proposed method via extensive simulations. The proposed method is also applied to a large twin eQTL data from the Netherlands Twin Register.

A cross-sectional study to examine the correlation between serum TSH levels and the osteoporosis of the lumbar spine in healthy women with normal thyroid function

We examined the association between serum TSH levels and osteoporosis of the lumbar spine in 756 Korean women aged 65 years or older with normal thyroid function. Low-normal serum TSH levels might be a potential risk factor for the osteoporosis in non-obese elderly women.

INTRODUCTION

We aimed to examine the association between serum thyroid-stimulating hormone (TSH) levels and osteoporosis of the lumbar spine in healthy elderly Korean women with normal thyroid function.

METHODS

In this cross-sectional study, we evaluated the correlations between serum TSH levels and the osteoporosis of the lumbar spine depending on the body mass index (BMI) in a total of 756 women aged 65 years or older who underwent bone mineral density (BMD) measurement and thyroid function test in a routine health screening examination at our medical institution.

RESULTS

After the adjustment of the age and BMI, there was a significant positive correlation between serum TSH level within normal range and the BMD of the lumbar spine (r = 0.165, P < 0.001). In the non-obese elderly women, multivariate-adjusted odds ratios (ORs) for the osteoporosis of the lumbar spine were significantly higher in the 1st and 2nd quartiles of serum TSH levels as compared with their 4th quartile (OR 2.169, 95% CI 1.128-4.171; and OR 2.122, 95% CI 1.123-4.007, respectively). In these women, there were dose-dependent inverse correlations between quartiles of serum TSH levels and the osteoporosis of the lumbar spine (P for trend, 0.008). In the obese women, however, there were no such correlations.

CONCLUSIONS

In conclusion, our results suggest that low-normal serum TSH levels might be a potential risk factor for the osteoporosis of the lumbar spine in non-obese elderly women. But further prospective, large-scale, randomized controlled studies are warranted to establish our results.

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.