Relationship Between Sarcopenia and Fracture Risks in Obese Postmenopausal Women

Obesity paradox in older sarcopenic adults - a delay in aging: A systematic review and meta-analysis

The prognostic significance of obesity in sarcopenic adults is controversial. This systematic review and meta-analysis aimed to investigate the effect of additional obesity on health outcomes in sarcopenia. MEDLINE, EMBASE, Scopus and CENTRAL were systematically searched for studies to compare health outcomes of adults with sarcopenic obesity (SO) to those of sarcopenic non-obese (SNO) adults. We also considered the methods of assessing obesity. Of 15060 records screened, 65 papers were included (100612 participants). Older community-dwelling SO adults had 15% lower mortality risk than the SNO group (hazard ratio, HR: 0.85, 95% confidence interval 0.76, 0.94) even when obesity was assessed by measurement of body composition. Additionally, meta-regression analysis revealed a significant negative linear correlation between the age and the HR of all-cause mortality in SO vs. SNO community-dwelling adults, but not in severely ill patients. Compared with SNO, SO patients presented lower physical performance, higher risk for metabolic syndrome, but similar cognitive function, risk of falls and cardiovascular diseases. Age-related obesity, SO and later fat loss leading to SNO represent consecutive phases of biological aging. Additional obesity could worsen the health state in sarcopenia, but above 65 years SO represents a biologically earlier phase with longer life expectancy than SNO.

Irisin and Bone in Sickness and in Health: A Narrative Review of the Literature

Irisin is a hormone-like myokine produced by the skeletal muscle in response to exercise. Upon its release into the circulation, it is involved in the browning process and thermogenesis, but recent evidence indicates that this myokine could also regulate the functions of osteoblasts, osteoclasts, and osteocytes. Most human studies have reported that serum irisin levels decrease with age and in conditions involving bone diseases, including both primary and secondary osteoporosis. However, it should be emphasized that recent findings have called into question the importance of circulating irisin, as well as the validity and reproducibility of current methods of irisin measurement. In this review, we summarize data pertaining to the role of irisin in the bone homeostasis of healthy children and adults, as well as in the context of primary and secondary osteoporosis. Additional research is required to address methodological issues, and functional studies are required to clarify whether muscle and bone damage per se affect circulating levels of irisin or whether the modulation of this myokine is caused by the inherent mechanisms of underlying diseases, such as genetic or inflammatory causes. These investigations would shed further light on the effects of irisin on bone homeostasis and bone disease.

Falls, fractures, and areal bone mineral density in older adults with sarcopenic obesity: A systematic review and meta-analysis

Sarcopenia and obesity are common conditions in older adults that may have differing effects on falls and fracture risk. This systematic review and meta-analysis aimed to determine whether older adults with sarcopenic obesity have increased risk of falls and fractures or lower bone mass compared with older adults with sarcopenia, obesity, or neither condition. Twenty-six studies (n = 37,124) were included in the systematic review and 17 (n = 31,540) were included in the meta-analysis. Older adults with sarcopenic obesity had lower femoral neck areal bone mineral density (aBMD) compared with those with obesity alone but had higher femoral neck aBMD compared with counterparts with sarcopenia alone (both P < 0.05). Older adults with sarcopenic obesity had higher nonvertebral fracture rates (incidence rate ratio: 1.88; 95% confidence intervals: 1.09, 3.23; based on two studies), compared with those with sarcopenia alone, and also had higher falls risk compared with controls (risk ratio: 1.30; 95% confidence intervals: 1.10, 1.54) and obesity alone (risk ratio: 1.17; 95% confidence intervals: 1.01, 1.36). In conclusion, this systematic review and meta-analysis has demonstrated that older adults with sarcopenic obesity are at increased risk of adverse musculoskeletal outcomes compared with individuals with obesity, sarcopenia, or neither condition. These data support the need for developing interventions to improve bone health and physical function in this population.

Effects of Exercise Training on the Autophagy-Related Muscular Proteins Expression in Ovariectomized Rats

Ovariectomy disrupts estrogen production and homeostasis. However, whether exercise training (ET) could counteract the ovariectomy-induced effect on muscular autophagy has remained elusive. This study examined muscular autophagy in ovariectomized (OVX) rats following 8 weeks of swimming ET. Here, 40 6-month-old female Sprague-Dawley rats were randomly divided into five groups: sham-operated control (Sham), OVX control (OVX), OVX with 60-min ET (OVX-60ET), 90-min ET (OVX-90ET), and 120-min ET (OVX-120ET) for 6 days/week. According to the results of Western blotting, the expression levels of autophagy-related proteins in the OVX gastrocnemius muscle, including mammalian target of rapamycin, uncoordinated 51-like kinase 1, Beclin-1, autophagy-related gene (Atg-7), and microtubule-associated protein light chains 3 were significantly decreased (all P < 0.05), while there was an elevation on the p62 level. ET appreciably mitigated the OVX-induced negative effects on muscle quality and the autophagy pathway, which seemed to be dependent on ET volume. The most optimal outcomes were observed in the OVX-90ET group. The OVX-120 group had an adversely augmented catabolic process associated with gastrocnemius muscle atrophy. In conclusion, the expression levels of autophagy proteins are decreased in OVX rats, which can be appreciably mitigated following 8 weeks of swimming ET.

The Effect of Sarcopenia on Outcomes in Geriatric Blunt Trauma

Elderly patients are at a higher risk of morbidity and mortality after trauma, which is reflected through higher frailty indices. Data collection using existing frailty indices is often not possible because of brain injury, dementia, or inability to communicate with the patient. Sarcopenia is a reliable objective measure for frailty that can be readily assessed in CT imaging. In this study, we aimed to evaluate the effect of sarcopenia on the outcomes of geriatric blunt trauma patients. Left psoas area (LPA) was measured at the level of the third lumbar vertebra on the axial CT images. LPA was normalized for height (LPA mm2/m2) and after stratification by gender, sarcopenia was defined as LPA measurements in the lowest quartile. A total of 1175 patients consisting of 597 males and 578 females were studied. LPAs below 242.6 mm2/m2 in males and below 187.8 mm2/m2 in females were considered to be sarcopenic. We found sarcopenia in 149 males and 145 females. In multivariate analysis, sarcopenia was associated with a higher risk of in-hospital mortality (odds ratio [OR]: 1.61, 95% confidence interval [CI]: 1.01–2.56) and a higher risk of discharge to less favorable destinations (OR: 1.42, 95% CI: 1.05–1.97). Lastly, sarcopenic patients had an increased risk of prolonged hospitalization (hazard ratio: 1.21, 95% CI: 1.04–1.40).

Associations of Sarcopenic Obesity and Dynapenic Obesity with Bone Mineral Density and Incident Fractures Over 5-10 Years in Community-Dwelling Older Adults

The purpose of this study is to determine whether low muscle mass (sarcopenia) or strength (dynapenia), in the presence of obesity, are associated with increased risk for osteoporosis and non-vertebral fracture over 5-10 years in community-dwelling older adults. N = 1089 volunteers (mean ± SD age 62 ± 7 years; 51 % female) participated at baseline and 761 attended follow-up clinics (mean 5.1 ± 0.5 years later). Total body, total hip and spine BMD, and appendicular lean and total fat mass were assessed by DXA. Sarcopenic obesity and dynapenic obesity were defined as the lowest sex-specific tertiles for appendicular lean mass or lower-limb strength, respectively, and the highest sex-specific tertile for total fat mass. Fractures were self-reported on three occasions over 10.7 ± 0.7 years in 563 participants. Obese alone participants had significantly higher BMD at all sites compared with non-sarcopenic non-obese. Sarcopenic obese and dynapenic obese men had lower spine and total body BMD, respectively, and sarcopenic obese women had lower total hip BMD, compared with obese alone (all P < 0.05). Sarcopenic obese men had higher non-vertebral fracture rates compared to non-sarcopenic non-obese (incidence rate ratio: 3.0; 95 % CI 1.7-5.5), and obese alone (3.6; 1.7-7.4). Sarcopenic obese women had higher fracture rates compared with obese alone (2.8; 1.4-5.6), but this was non-significant after adjustment for total hip BMD. Sarcopenic and dynapenic obese older adults may have increased risk of osteoporosis and non-vertebral fracture relative to obese alone counterparts. Sarcopenic and dynapenic obese individuals potentially represent a subset of the obese older adult population who require closer monitoring of bone health during ageing.

Weekly time spent in the standing position is independently related to a better quality of life in postmenopausal women

OBJECTIVES

To analyze the relationship between standing, sitting and reclining behaviors and quality of life in postmenopausal women.

STUDY DESIGN

Cross-sectional study composed of forty postmenopausal women (aged 59.58±5.32) who do not practice regular physical exercise. Body composition was measured using Dual-energy X-ray absorptiometry and quality of life by the Short Form 36 Health Survey (SF-36). Physical activity level was assessed using an accelerometer (Actigraph GTX3x) and is reported as minutes per week of moderate-to-vigorous physical activity (MVPA). Inclinometer analysis was also measured using this accelerometer model and reported as a weekly percentage of time spent standing, sitting and reclining. All analyses were performed using SPSS 17.0 software with the significance level set at 5%.

RESULTS

The percentage of time in the standing position was lower among women with poor quality of life (p<0.05). Adjusted analysis (age, years since menopause, percentage of fat mass, MVPA and occupation status) was used to evaluate the relationship between quality of life and accelerometer inclinometer measures. The relationship between time standing and general health status (β=0.353; 95%CI=0.017; 0.377), social function (β=0.429; 95%CI=0.060; 0.396) and overall score (β=0.336; 95%CI=0.015; 0.442) were statistically significant. The relationship between the reclining position and both overall score (β=-0.320; 95%CI=-0.492; 0.006) and emotional aspects (β=-0.337; 95%CI=-0.191; 0.001) showed a tendency to present statistical significance.

CONCLUSION

In summary, our results suggest that postmenopausal women who spend more time in the standing position have a better overall quality of life regardless of confounders.

Fall and Fracture Risk in Sarcopenia and Dynapenia With and Without Obesity: the Role of Lifestyle Interventions

Due to their differing etiologies and consequences, it has been proposed that the term "sarcopenia" should revert to its original definition of age-related muscle mass declines, with a separate term, "dynapenia", describing muscle strength and function declines. There is increasing interest in the interactions of sarcopenia and dynapenia with obesity. Despite an apparent protective effect of obesity on fracture, increased adiposity may compromise bone health, and the presence of sarcopenia and/or dynapenia ("sarcopenic obesity" and "dynapenic obesity") may exacerbate the risk of falls and fracture in obese older adults. Weight loss interventions are likely to be beneficial for older adults with sarcopenic and dynapenic obesity but may result in further reductions in muscle and bone health. The addition of exercise including progressive resistance training and nutritional strategies, including protein and vitamin D supplementation, may optimise body composition and muscle function outcomes thereby reducing falls and fracture risk in this population.

Irisin is associated with osteoporotic fractures independently of bone mineral density, body composition or daily physical activity

BACKGROUND

Although there is an evidence of correlation between irisin and osteoporotic fractures, previous studies have not elucidated the relationship between irisin and either lean or fat mass. The main aim of this study is to investigate the relationship between irisin and body composition in postmenopausal women with osteoporosis and the impact of irisin levels on fragility vertebral fractures.

METHODS

In this cross-sectional study, 36 overweight subjects affected by at least one vertebral osteoporotic fracture confirmed by an X-ray vertebral morphometry and 36 overweight nonosteoporotic subjects were enrolled. Serum irisin levels were measured using an irisin competitive ELISA. We evaluated lumbar spine and hip BMD and body composition using dual energy X-ray absorptiometry. To measure and monitor daily physical activity, each subject wore an armband for approximately 72 h.

RESULTS

No significant correlations were found between irisin and BMD at any site and between irisin with either lean or fat mass. Serum levels of irisin were not correlated with the daily physical activity. Serum irisin levels were lower in subjects with previous osteoporotic fractures than in controls (P = 0·032), and the difference in irisin levels remained significant after adjustment for creatinine (P = 0·037), vitamin D (P = 0·046), lean mass (P = 0·02), lumbar BMD (P = 0·023) and femoral BMD (P = 0·032).

CONCLUSION

Our data confirm an inverse correlation between irisin levels and vertebral fragility fractures, but no significant correlation was found with BMD or lean mass. Irisin may play a protective role on bone health independent of BMD but further studies are needed to clarify the relationship between irisin and bone metabolism.

Effect of combined aerobic and resistance training in body composition of obese postmenopausal women

The aim of this study was to investigate the effects of a 16-week program of combined aerobic and resistance training on the body composition of postmenopausal women who are obese. The participants were divided into two groups: training group (TG, n = 37) and non-trained control group (CG, n = 18). The trunk fat, fat mass, percentage of fat mass and fat-free mass were estimated using DXA. Three nonconsecutive 24-hour dietary recalls were conducted. The training protocol consisted of 50 minutes of resistance training followed by 30 minutes of aerobic training. After the 16-week training program, differences were observed in trunk fat (CG= 0.064 x TG= -0.571 Kg; p-value = .020), fat mass (CG= -0.088 x TG= -1.037 Kg; p-value = .020) and fat-free mass (CG= -0.388 x TG= 1.049 Kg; p = .001). Therefore, a 16-week program of systematic combined aerobic and resistance training in obese postmenopausal women was effective in improving fat-free mass and decreasing both whole and abdominal adiposity.

Is the negative relationship between obesity and bone mineral content greater for older women?

Obesity and osteoporosis are two important body composition problems with increasing prevalences in aged populations. Traditionally, obesity has been regarded as being beneficial to bone health. However, the protective effect of obesity on osteoporosis has been questioned. In some recent studies, obesity, as defined by percentage body fat, was regarded as a risk factor for osteoporosis. The purpose of this study was to (1) evaluate the effect of waist circumference, a surrogate measure for abdominal obesity, on bone mineral content (BMC) and (2) examine whether the effect of waist circumference increases with advancing age. The study population is made up of women aged over 45 years who completed the body composition and bone mineral density examinations in the fifth Korea National Health and Nutrition Examination Survey in 2010. Subjects who take estrogen or are under medical treatment for osteoporosis were excluded. Stroke patients are also excluded. Femoral neck, total-hip, and whole-body BMC were measured by dual-energy X-ray absorptiometry. A total of 1,434 subjects were included in the analysis. Waist circumference was negatively associated with BMC in all tested regions after correction for weight, menopausal status, smoking, drinking, and exercise. In addition, the negative association between waist circumference and BMC in the femoral neck and total hip increases with age, after correction for confounding factors, showing an interaction effect between waist circumference and age on BMC. In conclusion, this study shows that the negative relationship between waist circumference and BMC in the femoral neck and total hip is greater for older women.

Balance control in elderly people with osteoporosis

Osteoporosis is a prevalent health concern among older adults and is associated with an increased risk of falls that incur fracture, injury, or mortality. Identifying the risk factors of falls within this population is essential for the development of effective regimes for fall prevention. Studies have shown that muscle quality and good posture alignments are critical for balance control in elderly individuals. People with osteoporosis often have muscle weakness and increased spine kyphosis leading to vertebral fractures and poor balance control, or even falls. Therefore, improving muscle quality, strengthening weak muscles, and correcting postural alignment are essential elements for the prevention of falls and fractures in older adults with osteoporosis. This review reports the necessary information regarding the critical factors of balance control in older adults with osteoporosis, as well as testing the clinical innovations of exercise training to improve the long-term prognosis of osteoporosis in this vulnerable population.

Effects of diet-induced obesity and voluntary wheel running on the microstructure of the murine distal femur

Background

Obesity and osteoporosis, two possibly related conditions, are rapidly expanding health concerns in modern society. Both of them are associated with sedentary life style and nutrition. To investigate the effects of diet-induced obesity and voluntary physical activity we used high resolution micro-computed tomography (μCT) together with peripheral quantitative computed tomography (pQCT) to examine the microstructure of the distal femoral metaphysis in mice.

Methods

Forty 7-week-old male C57BL/6J mice were assigned to 4 groups: control (C), control + running (CR), high-fat diet (HF), and high-fat diet + running (HFR). After a 21-week intervention, all the mice were sacrificed and the left femur dissected for pQCT and μCT measurements.

Results

The mice fed the high-fat diet showed a significant weight gain (over 70% for HF and 60% for HFR), with increased epididymal fat pad mass and impaired insulin sensitivity. These obese mice had significantly higher trabecular connectivity density, volume, number, thickness, area and mass, and smaller trabecular separation. At the whole bone level, they had larger bone circumference and cross-sectional area and higher density-weighted maximal, minimal, and polar moments of inertia. Voluntary wheel running decreased all the cortical bone parameters, but increased the trabecular mineral density, and decreased the pattern factor and structure model index towards a more plate-like structure.

Conclusions

The results suggest that in mice the femur adapts to obesity by improving bone strength both at the whole bone and micro-structural level. Adaptation to running exercise manifests itself in increased trabecular density and improved 3D structure, but in a limited overall bone growth

Effects of diet-induced obesity and voluntary wheel running on bone properties in young male C57BL/6J mice

Both physical activity and body mass affect bone properties. In this study we examined how diet-induced obesity combined with voluntary physical activity affects bone properties. Forty 7-week-old male C57BL/6J mice were assigned to four groups evenly: control diet (C), control diet + running (CR), high-fat diet (HF, 60% energy from fat), and high-fat diet + running (HFR). After 21-week intervention, all mice were killed and the left femur was dissected for pQCT and mechanical measurements. Body mass increased 80% in HF and 62% in HFR, with increased epididymal fat pad weight and impaired insulin sensitivity. Except for total and trabecular volumetric bone mineral density (BMD), bone traits correlated positively with body mass, fat pad, leptin, and osteoprotegerin. Obesity induced by a high-fat diet resulted in increased femoral bone cross-sectional area, mineral content (BMC), polar moment of inertia, and mechanical parameters. Of the mice accessing the running wheel, those fed the control diet had thinner cortex and less total metaphyseal BMC and BMD, with enlarged metaphyseal marrow cavity, whereas mice fed the high-fat diet had significantly higher trabecular BMD and smaller marrow cavity. However, the runners had a weaker femoral neck as indicated by decreased maximum flexure load. These results suggest that voluntary running exercise affects bone properties in a site-specific manner and that there is a complex interaction between physical activity and obesity. Thus, both diet and exercise should be considered when optimizing the effects on body composition and bone, even though the underlying mechanisms remain partly unknown.