Relationship of lean body mass with bone mass and bone mineral density in the general Korean population

Associations of visceral adipose tissue with bone mineral density and fracture: observational and Mendelian randomization studies

BACKGROUND

The associations between visceral adipose tissue (VAT) and bone mineral density (BMD) or fracture have been controversial and the causality of the associations remains to be assessed. This study aimed to explore the associations of VAT^ (predicted value of VAT mass) with BMD and fracture risk in men and women, and to examine their potential causation by two-sample Mendelian randomization (MR) analyses.

METHODS

UK Biobank is a large, population-based prospective cohort study that recruited more than 500,000 participants aged 40-69 in the United Kingdom from 2006 to 2010. In this study, we used a validated and reliable prediction model to estimate the VAT amount of the participants. On this basis, linear and nonlinear multivariable statistical models were used to explore the association of VAT^ with BMD and fracture risk in different groups of sex and BMI. In observational analyses, the multivariable linear regression model and Cox proportional-hazards model were used to assess VAT^ association with BMD and fracture risk, respectively. Inverse variance weighting was used as the main result of MR analysis.

RESULTS

In 190,836 men, an inverted U-shaped association was observed between VAT^ and heel BMD (P for nonlinearity < 0.001), with a turning point of VAT^ = 1.25 kg. Per kg increase in VAT^ was associated with a 0.13 standard deviation (SD) increase in heel BMD (P = 1.5 × 10^-16) among men with lower amounts of VAT^, and associated with a 0.05 SD decrease in heel BMD (P = 1.3 × 10^-15) among men with higher amounts of VAT^. In 193,592 women, per kg increase in VAT^ was monotonically associated with a 0.16 SD increase in heel BMD (P = 1.2 × 10^-136, P for VAT^-sex interaction = 8.4 × 10^-51). During a median follow-up of 8.2 years, VAT^ was associated with lower risks of hip fractures in the overall men and women (P for VAT^-sex interaction = 1.9 × 10^-4 for total fractures; 1.5 × 10^-4 for other fractures). There were significant interactions of VAT^ and BMI on heel BMD and fracture risks in men only (P for VAT^-BMI interaction = 5.9 × 10^-31 for heel BMD; 2.7 × 10^-4 for total fractures; 5.7 × 10^-3 for hip fractures; 6.8 × 10^-3 for other fractures). In two-sample MR analyses, evidence of causality was not observed between VAT^ and DXA-derived BMD or fractures.

CONCLUSIONS

These novel findings demonstrated gender-dependent associations of VAT^ with BMD and fracture risk, with the association in men being modified by adiposity. Evidence of causality was not observed, suggesting that the observational association of VAT^ with BMD and fracture risk could be the result of confounding.

Effect of metformin and insulin vs. placebo and insulin on whole body composition in overweight patients with type 2 diabetes: a randomized placebo-controlled trial

Some studies indicate potential beneficial effects of metformin on body composition and bone. This trial compared metformin + insulin vs placebo + insulin. Metformin treatment had a small but positive effect on bone quality in the peripheral skeleton, reduced weight gain, and resulted in a more beneficial body composition compared with placebo in insulin-treated patients with type 2 diabetes.

INTRODUCTION

Glucose-lowering medications affect body composition. We assessed the long-term effects of metformin compared with placebo on whole body bone and body composition measures in patients with type 2 diabetes mellitus.

METHODS

This was a sub-study of the Copenhagen Insulin and Metformin Therapy trial, which was a double-blinded randomized placebo-controlled trial assessing 18-month treatment with metformin compared with placebo, in combination with different insulin regimens in patients with type 2 diabetes mellitus (T2DM). The sub-study evaluates the effects on bone mineral content (BMC), density (BMD), and body composition from whole body dual-energy X-ray absorptiometry (DXA) scans which were assessed at baseline and after 18 months.

RESULTS

Metformin had a small, but positive, (p < 0.05) effect on subtotal, appendicular, and legs BMC and BMD compared with placebo. After adjustment for sex, age, vitamin D, smoking, BMI, T2DM duration, HbA1c, and insulin dose, the effects on appendicular BMC and BMD persisted (p < 0.05 for both). The changes in appendicular BMC and BMD corresponded approximately to a 0.7% and 0.5% increase in the metformin group and 0.4% and 0.4% decrease in the placebo group, respectively. These effects were mostly driven by an increase in BMC and BMD in the legs and a loss of BMC and BMD in the arms. During 18 months, all participants increased in weight, fat mass (FM), FM%, and lean mass (LM), but decreased in LM%. The metformin group increased less in weight (subtotal weight (weight-head) - 2.4 [- 3.5, - 1.4] kg, p value < 0.001) and FM (- 1.5 [- 2.3, - 0.8] kg, p value < 0.001) and decreased less in LM% (0.6 [0.2, 1.1] %, p value < 0.001) compared with the placebo group.

CONCLUSION

Metformin treatment had a small positive effect on BMC and BMD in the peripheral skeleton and reduced weight gain compared with placebo in insulin-treated patients with T2DM.

Mediterranean Diet, Body Composition, and Activity Associated With Bone Health in Women With Fibromyalgia Syndrome

BACKGROUND

There is very little scientific literature on the potential relationships between modifiable factors, including body composition, dietary pattern and physical activity (PA), and bone status in patients with fibromyalgia-a musculoskeletal condition characterized by chronic, widespread pain that is often accompanied by a broad spectrum of symptoms.

OBJECTIVES

The aim of the study was to investigate the impact of body composition parameters, adherence to the Mediterranean diet (Med Diet), and PA on bone health in a population of premenopausal and postmenopausal women with fibromyalgia syndrome (FMS).

METHODS

Ninety-five women diagnosed with FMS were included in this cross-sectional study. Body composition, including fat mass, percentage of fat mass, and lean mass (LM), were calculated using a body composition analyzer. Adherence to the Med Diet was measured through a validated 14-item questionnaire. The International Physical Activity Questionnaire was used to assess PA. Bone mass at the calcaneus was estimated through quantitative ultrasound.

RESULTS

Linear regression analysis revealed that LM had a significant association with broadband ultrasound attenuation (β = 0.211, 95% CI [0.046, 1.259], p = .035) and stiffness index parameters (β = 0.201, 95% CI [0.019, 1.654], p = .045) after adjusting for age and menopausal status. The Med Diet was also significantly associated with broadband ultrasound attenuation (β = 1.693, 95% CI [0.508, 2.879], p = .006).

DISCUSSION

LM and the Med Diet were consistently associated with calcaneal quantitative ultrasound parameters, supporting the hypothesis that LM and adherence to the Med Diet play determinant roles in bone health in FMS women. Training programs to maximize LM and strategies for promoting good adherence to the Med Diet should be considered in order to prevent the development of osteoporosis in FMS women. Because nurses are involved in implementing preventive programs, their roles in promoting this adherence to the Med Diet and maximizing LM in patients with FMS should help reduce the impact of osteoporosis.

Increased Leg Bone Mineral Density and Content During the Initial Years of College Sport

Scerpella, JJ, Buehring, B, Hetzel, SJ, and Heiderscheit, BC. Increased leg bone mineral density and content during the initial years of college sport. J Strength Cond Res 32(4): 1123-1130, 2018-Bone mineral density (BMD) and bone mineral content (BMC) data are useful parameters for evaluating how training practices promote bone health. We used dual-energy X-ray absorptiometry (DXA) to longitudinally assess sport-specific growth in leg and total body BMD/BMC over the initial 2 years of collegiate training. Eighty-five Division 1 collegiate basketball, hockey, and soccer athletes (50 males and 35 females; age 19.0 [0.8] years) underwent annual DXA scans. Leg and total body BMD/BMC were compared within and across two 1-year intervals (periods 1 and 2) using repeated-measures analysis of variance, adjusting for age, sex, race, and sport. Leg BMD, leg BMC, and total body BMC all increased over period 1 (0.05 g·cm [p = 0.001], 0.07 kg [p = 0.002], and 0.19 kg [p < 0.001] respectively). Changes in period 2 compared with period 1 were smaller for leg BMD (p = 0.001), leg BMC (p < 0.001), leg fat mass (p = 0.028), and total BMC (p = 0.005). Leg lean mass increased more during period 2 than period 1 (p = 0.018). Sports participation was the only significant predictor of change in leg BMD. Significant increases in both leg BMD and BMC were demonstrated over both 2-year periods, with greater gains during period 1. These gains highlight the importance of attentive training procedures, capitalizing on attendant physical benefits of increased BMD/BMC. Additional research in young adults, evaluating bone mass acquisition, will optimize performance and decrease risk of bone stress injury among collegiate athletes.

Low Skeletal Muscle Mass is Associated with the Risk of Low Bone Mineral Density in Urban Dwelling Premenopausal Women

To evaluate the relationship between skeletal muscle mass and bone mineral density (BMD) and to determine the association between low skeletal muscle mass and low BMD in urban dwelling young adults. This study was based on data from the 2008-2011 Korea National Health and Nutrition Examination Surveys. The subjects were 1702 20-49-year-old men and 2192 premenopausal women (age 20-55 years). BMD at the lumbar spine, femoral neck, and total hip and the appendicular skeletal muscle mass (ASM) were measured by dual-energy X-ray absorptiometry. Skeletal muscle mass index (SMI) was defined as weight-adjusted ASM. Mildly and severely low muscle skeletal mass were defined as SMI that was 1-2 and >2 standard deviations below the sex-specific mean ASM of young adults, respectively. Low BMD was defined as T score of less than -1.0 at the lumbar spine, femoral neck, and/or total hip. After adjusting for confounders, skeletal muscle mass was positively associated with BMD at the lumbar spine, femoral neck, and total hip in both men and women. Mildly and severely low skeletal muscle mass increased the risk of low BMD in premenopausal women [OR (95% CI) = 1.4 (1.1-1.9) and 2.4 (1.2-4.6), respectively] but not men. In women, low skeletal muscle mass independently was associated with the risk of low BMD at the femoral neck and total hip but not the lumbar spine. Skeletal muscle mass was independently associated with BMD in urban dwelling young men and women, but low skeletal muscle mass was associated with the risk of low BMD in premenopausal women only.

Fat Mass Is Positively Associated with Estimated Hip Bone Strength among Chinese Men Aged 50 Years and above with Low Levels of Lean Mass

This study investigated the relationships of fat mass (FM) and lean mass (LM) with estimated hip bone strength in Chinese men aged 50-80 years (median value: 62.0 years). A cross-sectional study including 889 men was conducted in Guangzhou, China. Body composition and hip bone parameters were generated by dual-energy X-ray absorptiometry (DXA). The relationships of the LM index (LMI) and the FM index (FMI) with bone phenotypes were detected by generalised additive models and multiple linear regression. The associations between the FMI and the bone variables in LMI tertiles were further analysed. The FMI possessed a linear relationship with greater estimated hip bone strength after adjustment for the potential confounders (p < 0.05). Linear relationships were also observed for the LMI with most bone phenotypes, except for the cross-sectional area (p < 0.05). The contribution of the LMI (4.0%-12.8%) was greater than that of the FMI (2.0%-5.7%). The associations between the FMI and bone phenotypes became weaker after controlling for LMI. Further analyses showed that estimated bone strength ascended with FMI in the lowest LMI tertile (p < 0.05), but not in the subgroups with a higher LMI. This study suggested that LM played a critical role in bone health in middle-aged and elderly Chinese men, and that the maintenance of adequate FM could help to promote bone acquisition in relatively thin men.

Implications of exercise-induced adipo-myokines in bone metabolism

Physical inactivity has been recognized, by the World Health Organization as the fourth cause of death (5.5 % worldwide). On the contrary, physical activity (PA) has been associated with improved quality of life and decreased risk of several diseases (i.e., stroke, hypertension, myocardial infarction, obesity, malignancies). Bone turnover is profoundly affected from PA both directly (load degree is the key determinant for BMD) and indirectly through the activation of several endocrine axes. Several molecules, secreted by muscle (myokines) and adipose tissues (adipokines) in response to exercise, are involved in the fine regulation of bone metabolism in response to the energy availability. Furthermore, bone regulates energy metabolism by communicating its energetic needs thanks to osteocalcin which acts on pancreatic β-cells and adipocytes. The beneficial effects of exercise on bone metabolism depends on the intermittent exposure to myokines (i.e., irisin, IL-6, LIF, IGF-I) which, instead, act as inflammatory/pro-resorptive mediators when chronically elevated; on the other hand, the reduction in the circulating levels of adipokines (i.e., leptin, visfatin, adiponectin, resistin) sustains these effects as well as improves the whole-body metabolic status. The aim of this review is to highlight the newest findings about the exercise-dependent regulation of these molecules and their role in the fine regulation of bone metabolism.

Intradialytic aerobic cycling exercise alleviates inflammation and improves endothelial progenitor cell count and bone density in hemodialysis patients

Inflammation, endothelial dysfunction, and mineral bone disease are critical factors contributing to morbidity and mortality in hemodialysis (HD) patients. Physical exercise alleviates inflammation and increases bone density. Here, we investigated the effects of intradialytic aerobic cycling exercise on HD patients. Forty end-stage renal disease patients undergoing HD were randomly assigned to either an exercise or control group. The patients in the exercise group performed a cycling program consisting of a 5-minute warm-up, 20 minutes of cycling at the desired workload, and a 5-minute cool down during 3 HD sessions per week for 3 months. Biochemical markers, inflammatory cytokines, nutritional status, the serum endothelial progenitor cell (EPC) count, bone mineral density, and functional capacity were analyzed. After 3 months of exercise, the patients in the exercise group showed significant improvements in serum albumin levels, the body mass index, inflammatory cytokine levels, and the number of cells positive for CD133, CD34, and kinase insert domain-conjugating receptor. Compared with the exercise group, the patients in the control group showed a loss of bone density at the femoral neck and no increases in EPCs. The patients in the exercise group also had a significantly greater 6-minute walk distance after completing the exercise program. Furthermore, the number of EPCs significantly correlated with the 6-minute walk distance both before and after the 3-month program. Intradialytic aerobic cycling exercise programs can effectively alleviate inflammation and improve nutrition, bone mineral density, and exercise tolerance in HD patients.

Muscle mass is a strong correlation factor of total hip BMD among Korean premenopausal women

Objectives

This study was to investigate mean Z-score of BMD of Korean premenopausal women and also to investigate the relationship between BMD and body composition, such as skeletal muscle (SM) mass, body fat mass, and abdominal adiposity among healthy Korean premenopausal women in their forties.

Methods

A total of 2711 premenopausal women in her forties (40-49 years) who had taken dual energy X-ray absorptiometry (DXA) for BMD screening and body composition analyser (InBody J10^®) from 2012 to 2013 at health promotion center of Ewha Womans university Mokdong hospital were analyzed retrospectively. Demographic data such as body mass index (BMI), waist circumference (WC), hip circumference (HC), waist hip ratio (WHR), SM mass, body fat mass, and serum lipid profile were included in this study. The Pearson's correlation coefficient (CC) was used to identify co-efficiency between BMD and other parameters.

Results

The mean age was 44.2 ± 4.44 (years) and mean BMI was 22.43 ± 2.99 (kg/m²). Mean Z-score of BMD-lumbar 1-4 (BMD-L) and BMD-femur total hip (BMD-F) was 0.33 ± 1.14 and -0.19 ± 0.85. Mean of BMD-L and BMD-F were 1.18 ± 0.16 (g/cm²) and 0.96 ± 0.12 (g/cm²). Skeletal muscle mass showed a strong significant correlation coefficient (CC) only with BMD-F (CC = 0.13, p-value = 4.78 × 10^-11). However serum lipid profile, body fat mass, and WHR did not show significant CC with mean Z-score of BMD-F and BMD-L.

Conclusions

Skeletal muscle mass measured by body composition analyzer of BIA method is a strong correlation factor for BMD especially of hip bone among healthy Korean premenopausal women in their forties.

Adipocytokine and ghrelin levels in relation to bone mineral density in prepubertal rhythmic gymnasts entering puberty: a 3-year follow-up study

PURPOSE

To investigate changes in bone mineral density (BMD) in rhythmic gymnasts (RG) entering puberty and their age-matched untrained controls (UC) over the 36-month period, and associations with leptin, adiponectin and ghrelin over this period.

METHODS

Whole body (WB), lumbar spine (LS) and femoral neck (FN) BMD, WB bone mineral content (BMC), and leptin, adiponectin and ghrelin were measured in 35 RG and 33 UC girls at baseline and at 12-month intervals over the next 3 years. The change over the 36 months was calculated (∆ score).

RESULTS

The pubertal development over the next 36 months was slower in RG compard to UC, while there was no difference in bone age development between the groups. BMD at all sites was higher in RG in comparison with UC at every measurement point. ∆LS BMD and ∆FN BMD, but not ∆WB BMD and ∆WB BMC, were higher in RG compared with UC. None of the measured hormones at baseline or their ∆ scores correlated with ∆BMD and ∆BMC in RG. Baseline fat free mass correlated with ∆WB BMD and ∆WB BMC in RG, while baseline leptin was related to ∆WB BMC, ∆WB BMD and ∆LS BMD in UC.

CONCLUSIONS

Measured baseline hormones and their ∆ scores did not correlate with increases in bone mineral values in RG entering puberty. Although the pubertal development in RG was slower than in UC, high-intensity training appeared to increase BMD growth and counterbalance negative effects of slow pubertal develpment, lower fat mass and leptin in RG.

Associations between fat distribution and volumetric bone mineral density in Chinese adults

The aim of this study was to explore the association between fat distribution and volumetric bone mineral density (vBMD) in Chinese Adults. Using a cross-sectional investigation of 867 participants including 521 women and 346 men from China, vBMD and subcutaneous adipose tissue (SCAT) or visceral adipose tissue (VAT) were measured accordingly by quantitative computed tomography. The peak vBMD values of the spine were observed at ages 30-39 years in women and at ages 20-29 years in men. In women, the peak values of VAT and SCAT were observed, respectively, at ages ≥ 70 years and at the age range of 60-69 years. In men, the peak values of VAT and SCAT were observed, respectively, at ages ≥ 70 years and at ages 30-39 years. Using the correlation tests, there was no correlation between SCAT and vBMD in both genders. Most relationships between VAT and BMD were negative (r = -0.204, P < 0.01, in premenopausal women; r = -0.150, P < 0.05, in postmenopausal women; and r = -0.181, P < 0.05, in middle-aged men). After multiple linear regression analysis, no correlations were observed. There appears to be no correlation between fat distribution and vBMD in Chinese adults, and further studies are needed to explore associations between fat distribution and vBMD.