Association between sarcopenia and mortality in healthy older people

Associations of sit-up ability with sarcopenia classification measures in Japanese older women

To test the hypothesis that sit-up performance is associated with sarcopenia classification measures, 93 older women aged 53–78 years were divided into three groups based on achieved repetitions (30 s) for the sit-up performance test: Group 0 (G 0, n = 33) performed 0 repetitions, Group 1–9 (G 1–9, n = 30) performed between 1 and 9 repetitions, and Group 10+ (G 10+, n = 30) performed over 10 repetitions. Dual-energy X-ray absorptiometry-derived appendicular lean soft tissue mass (aLM), handgrip strength (HGS), usual walking speed, and chair stand were measured, and low muscle mass (aLM index) and poor physical function were defined according to previous studies. Age and body mass index were similar among the three groups. HGS was higher in G 10+ compared with G 0. The prevalence rate of low muscle mass was 30% for G 0, 20% for G 1–9, and 3% for G 10+. Low HGS was observed in both G 0 (24%) and G 1–9 (20%), but not in G 10+. Only two persons in G 0 were classified as slow walking speed. Our results suggest that sit-up performance may be a useful indicator to determine the extent of sarcopenia because low muscle mass and poor function were almost non-existent in individuals who could perform over 10 sit-ups.

The beneficial effects of aerobic and concurrent training on metabolic profile and body composition after detraining: a 1-year follow-up in postmenopausal women

BACKGROUND/OBJECTIVES

Aerobic and concurrent training (CT, aerobic and strength training) improves body composition and metabolic profile; however, it is not known whether these positive outcomes acquired after aerobic or CT are maintained long term (⩾6 months) after program interruption in postmenopausal women. This study investigated the changes in total and appendicular body composition, bone mineral density and metabolic profile following 16 weeks of aerobic or CT, and through 6 months and 1 year of detraining in postmenopausal women.

SUBJECTS/METHODS

In total, 60 postmenopausal women were divided into the following groups: aerobic (AT), aerobic plus strength training (CT) and control group (CG), and 31 participants were assessed for the 1 year follow-up. Body composition and bone mineral density were evaluated by dual-energy X-ray absorptiometry (DXA), and total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, triacylglycerol, glucose, insulin, leptin, adiponectin and plasminogen activator inhibitor-1 (PAI-1) were assessed.

RESULTS

There were main effects of time for arm fat mass, arm lean mass and trunk lean mass (P<0.05). There was a statistical difference between AT and CG for leg fat mass and percentage of fat (P<0.05). After 6 months of detraining, leg lean mass decreased in relation to post-intervention, and there was a statistically significant interaction for total and appendicular lean mass (P<0.05). There were differences between CT and CG in glucose and between AT and CG in glucose and triacylglycerol (P<0.05).

CONCLUSIONS

A duration of 16 weeks of aerobic or CT improved total and appendicular body composition and metabolic profile but after 6 months of detraining, leg lean mass returned to the values obtained pre-training in CT.

Effects of Aerobic and Resistance Training Combined with Fortified Milk on Muscle Mass, Muscle Strength, and Physical Performance in Older Adults: A Randomized Controlled Trial

OBJECTIVES

Fortified milk and resistance training (RT) increase muscle mass, muscle strength, and physical performance in older adults, but it remains unclear whether RT combined with aerobic training (AT) would have stronger effects on these outcomes. The purpose of this study was to examine the effects of aerobic and resistance training (ART) combined with fortified milk consumption on muscle mass, muscle strength, and physical performance in older adults.

DESIGN

Open-labeled randomized controlled trial.

SETTING

University of Tsukuba.

PARTICIPANTS

Fifty-six older adults aged 65-79.

INTERVENTION

Participants were randomly allocated into resistance training (RT + fortified milk, n = 28) and aerobic and resistance training (ART + fortified milk, n = 28) groups. All participants attended supervised exercise programs twice a week at University of Tsukuba and ingested fortified milk every day for 12 weeks. Skeletal muscle index ([SMI]: appendicular lean mass/height2) was assessed using dual-energy X-ray absorptiometry as a muscle mass measure. One-repetition maximum strength was measured using four kinds of resistance training machines (chest press, leg extension, leg curl, and leg press) as muscle strength measures. Sit-to-stand and arm curl tests were also assessed as physical performance measures.

MEASUREMENTS

The primary measurements were muscle mass and strength. The secondary outcomes were physical performance, blood samples, habitual diet, habitual physical activity, and medication use.

RESULTS

Although the muscle strength and physical performance measures significantly improved in both groups, SMI significantly improved in only the RT group. There was no significant difference in the change in SMI and muscle strength measures between the two groups. However, the change in sit-to-stand and arm curl measures in the ART group were significantly higher than those in the RT group.

CONCLUSIONS

These results suggest that AT before RT combined with fortified milk consumption has similar effects on skeletal muscle mass and strength compared with RT alone, but it may be a more useful strategy to improve physical performance in older adults. Although the mechanism of our intervention is uncertain, our program would be an effective prevention for sarcopenia in older adults.

The new ESPEN diagnostic criteria for malnutrition predict overall survival in hospitalised patients

BACKGROUND

In 2015 the European Society for Clinical Nutrition and Metabolism (ESPEN) presented new consensus criteria for the diagnosis of malnutrition. Whereas most previous definitions were based on involuntary weight loss and/or a low BMI, the ESPEN definition added Fat Free Mass Index (FFMI) to the set of criteria.

AIM

To study the predictive value of the new ESPEN diagnostic criteria for malnutrition on survival, with specific focus on the additional value of FFMI.

METHODS

Included were 335 hospitalized adult patients of the VU University Medical Center Amsterdam (60% female, age 58 ± 18 y). Three sets of criteria for malnutrition were used to study the predictive value for survival: Dutch definition for malnutrition, ESPEN diagnostic criteria for malnutrition and ESPEN diagnostic criteria for malnutrition without FFMI criterion. The association between malnutrition and three-months and one-year overall survival was analyzed by log rank tests and Cox regression. In multivariate analyses, adjustments were made for gender, age, care complexity and length of stay.

RESULTS

Ninety patients (27%) were classified as malnourished by any of the sets of criteria; malnourished patients had significant lower survival rates than non-malnourished patients at three months (84% vs 94%; p = 0.01) and one year (76% vs 87%; p = 0.02). After adjustments, malnutrition remained significantly associated with three-months survival for the Dutch definition for malnutrition (HR:2.25, p = 0.04) and the ESPEN diagnostic criteria for malnutrition (HR:2.76, p = 0.02). Malnutrition remained significantly associated with one-year survival for the ESPEN diagnostic criteria for malnutrition (HR:2.17, p < 0.02) and the ESPEN diagnostic criteria for malnutrition without FFMI (HR:2.66, p < 0.01).

CONCLUSION

The new ESPEN definition for malnutrition is predictive for both three-months and one-year survival in a general hospital population, whereas definitions without FFMI are predictive for either three-months or one year survival.

Sarcopenia and Endothelial Function in Patients With Chronic Heart Failure: Results From the Studies Investigating Comorbidities Aggravating Heart Failure (SICA-HF)

OBJECTIVES

Skeletal muscle wasting, also known as sarcopenia, has recently been identified as a serious comorbidity in patients with heart failure (HF). We aimed to assess the impact of sarcopenia on endothelial dysfunction in patients with HF with reduced ejection fraction (HFrEF) and with preserved ejection fraction (HFpEF).

DESIGN

Cross-sectional study.

SETTING

Ambulatory patients with HF were recruited at Charité Medical School, Campus Virchow-Klinikum, Berlin, Germany.

PARTICIPANTS

We assessed peripheral blood flow (arm and leg) in 228 patients with HF and 32 controls who participated in the Studies Investigating Comorbidities Aggravating HF (SICA-HF).

MEASUREMENTS

The appendicular skeletal muscle mass of the arms and the legs combined was assessed by dual energy x-ray absorptiometry (DEXA). Sarcopenia was defined as the appendicular muscle mass two standard deviations below the mean of a healthy reference group of adults aged 18 to 40 years, as suggested for the diagnosis of muscle wasting in healthy aging. All patients underwent a 6-minute walk test and spiroergometry testing. Forearm and leg blood flow were measured by venous occlusion plethysmography. Peak blood flow was assessed after a period of ischemia in the limbs to test endothelial function.

RESULTS

Sarcopenia was identified in 37 patients (19.5%). Patients with sarcopenia presented with lower baseline forearm blood flow (2.30 ± 1.21 vs. 3.06 ± 1.49 vs. 4.00 ± 1.66 mL min^-1 100 mL^-1; P = .02) than those without sarcopenia or controls. The group of patients with sarcopenia showed similar baseline leg blood flow (2.06 ± 1.62 vs. 2.39 ± 1.39 mL min^-1 100 mL^-1; P = .11) to those without but lower values when compared to controls (2.06 ± 1.62 vs. 2.99 ± 1.28 mL min^-1 100 mL^-1; P = .03). In addition, patients with and without sarcopenia presented with lower peak flow in the forearm when compared to controls (18.37 ± 7.07 vs. 22.19 ± 8.64 vs. 33.63 ± 8.57 mL min^-1 100 mL^-1; P < .001). A similar result was observed in the leg (10.89 ± 5.61 vs. 14.66 ± 7.19 vs. 21.37 ± 13.16 mL min^-1 100 mL^-1; P < .001). Peak flow in the forearm showed a significant correlation with exercise capacity (relative peak VO₂: R = 0.47; P < .001; absolute peak VO₂: R = 0.35; P < .001; and 6-min walk distance: R = 0.20; P < .01). Similar correlations were observed between peak flow in the leg and exercise capacity (absolute peak VO₂: R = 0.42, P < .001; relative peak VO₂: R = 0.41, P < .001; and 6-min walk test: R = 0.33; P < .001). Logistic regression showed peak flow in the leg to be independently associated with the 6-min walk distance adjusted for age, hemoglobin level, albumin, creatinine, presence of sarcopenia, and coronary artery disease (hazard ratio, 0.903; 95% confidence interval, 0.835-0.976; P = .01).

CONCLUSION

Patients with HF associated with sarcopenia have impaired endothelial function. Lower vasodilatation had a negative impact on exercise capacity, particularly prevalent in patients with sarcopenia.

Does the muscle protein synthetic response to exercise and amino acid-based nutrition diminish with advancing age? A systematic review

The precise role of age-related muscle anabolic resistance in the progression of sarcopenia and functional decline in older individuals is unclear. The present aim was to assess whether the muscle protein synthesis (MPS) response to acute exercise (endurance or resistance) and/or amino acid-based nutrition is attenuated in older compared with young individuals. A systematic review was conducted on studies that directly examined the influence of age on the MPS response to exercise and/or amino acid-based nutrition. Each study arm was synthesized and reported as providing sufficient or insufficient "evidence of age-related muscle anabolic resistance". Subsequently, three models were established to compare age-related differences in the MPS response to 1) exercise alone, 2) amino acid-based nutrition alone, or 3) the combination of exercise and amino acid-based nutrition. Following exercise alone, 8 of the 17 study arms provided sufficient evidence of age-related muscle anabolic resistance, while in response to amino acid-based nutrition alone, 8 of the 21 study arms provided sufficient evidence of age-related muscle anabolic resistance. When exercise and amino acid-based nutrition were combined, only 2 of the 10 study arms provided sufficient evidence of age-related muscle anabolic resistance. Our results highlight that optimization of exercise and amino acid-based nutrition is sufficient to induce a comparable MPS response between young and older individuals. However, the exercise volume completed and/or the amino acid/protein dose and leucine content must exceed a certain threshold to stimulate equivalent MPS rates in young and older adults, below which age-related muscle anabolic resistance may become apparent.

Age-related sarcopenia and its pathophysiological bases

Age-related loss of the skeletal muscle and its function is known as sarcopenia. Definition and diagnostic criteria for sarcopenia have been outlined as consensus statements from several study groups, including usual gait speed, grip strength, and skeletal muscle mass. Whereas underlying mechanisms and pathophysiology of sarcopenia remains to be clarified, recent studies have suggested that chronic inflammatory status as well as lifestyle-related factors in older individuals might contribute to the process and progress of sarcopenia.

Ultrasound-Derived Forearm Muscle Thickness Is a Powerful Predictor for Estimating DXA-Derived Appendicular Lean Mass in Japanese Older Adults

To test the validity of published equations, anterior forearm muscle thickness (MT-ulna) of 158 Japanese older adults (72 men and 86 women) aged 50-79 y was measured with ultrasound. Appendicular lean soft tissue mass (aLM) was estimated from MT-ulna using two equations (body height without [eqn 1] and with [eqn 2]) previously published in the literature. Appendicular lean mass was measured using dual-energy X-ray absorption (DXA), and this method served as the reference criterion. There was a strong correlation between DXA-derived and ultrasound-estimated aLM in both equations (r = 0.882 and r = 0.944). Total error was 2.60 kg for eqn (1) and 1.38 kg for eqn (2). A Bland-Altman plot revealed that there was no systematic bias between DXA-derived and ultrasound-estimated aLM; however, eqn (1) overestimated aLM compared with DXA-derived aLM. Our results suggest that an ultrasound MT-ulna equation that includes body height is appropriate and useful for estimating aLM in Japanese adults.

The Association between Total Protein and Vegetable Protein Intake and Low Muscle Mass among the Community-Dwelling Elderly Population in Northern Taiwan

Sarcopenia, highly linked with fall, frailty, and disease burden, is an emerging problem in aging society. Higher protein intake has been suggested to maintain nitrogen balance. Our objective was to investigate whether pre-sarcopenia status was associated with lower protein intake. A total of 327 community-dwelling elderly people were recruited for a cross-sectional study. We adopted the multivariate nutrient density model to identify associations between low muscle mass and dietary protein intake. The general linear regression models were applied to estimate skeletal muscle mass index across the quartiles of total protein and vegetable protein density. Participants with diets in the lowest quartile of total protein density (<13.2%) were at a higher risk for low muscle mass (odds ratio (OR) 3.03, 95% confidence interval (CI) 1.37–6.72) than those with diets in the highest quartile (≥17.2%). Similarly, participants with diets in the lowest quartile of vegetable protein density (<5.8%) were at a higher risk for low muscle mass (OR 2.34, 95% CI 1.14–4.83) than those with diets in the highest quartile (≥9.4%). Furthermore, the estimated skeletal muscle mass index increased significantly across the quartiles of total protein density (p = 0.023) and vegetable protein density (p = 0.025). Increasing daily intakes of total protein and vegetable protein densities appears to confer protection against pre-sarcopenia status.

Sarcopenia and mortality among a population-based sample of community-dwelling older adults

BACKGROUND

Sarcopenia is a risk-factor for all-cause mortality among older adults, but it is unknown if sarcopenia predisposes older adults to specific causes of death. Further, it is unknown if the prognostic role of sarcopenia differs between males and females, and obese and non-obese individuals.

METHODS

A population-based cohort study among 4425 older adults from the Third National Health and Nutrition Survey (1988-1994). Muscle mass was quantified using bioimpedance analysis, and muscle function was quantified using gait speed. Multivariable-adjusted Cox regression analysis examined the relationship between sarcopenia and mortality outcomes.

RESULTS

The mean age of study participants was 70.1 years. The prevalence of sarcopenia was 36.5%. Sarcopenia associated with an increased risk of all-cause mortality [hazard ratio (HR): 1.29 (95% confidence interval (95% CI): 1.13-1.47); P < 0.001] among males and females. Sarcopenia associated with an increased risk of cardiovascular-specific mortality among females [HR: 1.61 (95% CI: 1.22-2.12); P = 0.001], but not among males [HR: 1.07 (95% CI: 0.81-1.40; P = .643); P interaction = 0.079]. Sarcopenia was not associated with cancer-specific mortality among males and females [HR: 1.07 (95% CI: 0.78-1.89); P = 0.672]. Sarcopenia associated with an increased risk of mortality from other causes (i.e. non-cardiovascular and non-cancer) among males and females [HR: 1.32 (95% CI: 1.07-1.62); P = 0.008]. Obesity, defined using body mass index (P interaction = 0.817) or waist circumference (P interaction = 0.219) did not modify the relationship between sarcopenia and all-cause mortality.

CONCLUSIONS

Sarcopenia is a prevalent syndrome that is associated with premature mortality among community-dwelling older adults. The prognostic value of sarcopenia may vary by cause-specific mortality and differ between males and females.

Association of estimated glomerular filtration rate with all-cause and cardiovascular mortality: the role of malnutrition-inflammation-cachexia syndrome

BACKGROUND

Previous studies have demonstrated that high estimated glomerular filtration rate (eGFR) is paradoxically associated with an increased risk of mortality, and the association becomes more predominant in older people. However, the role of malnutrition-inflammation-cachexia syndrome (MICS) in the association between eGFR and mortality has never been explored.

METHODS

We conducted a community-based cohort study using data from the Taipei City Elderly Health Examination Database, collected during the period 2001-10. All participants aged ≥65 years were included and stratified by the absence or presence of MICS, which is defined as the presence of at least one of the following markers: body mass index <22 kg/m(2), serum albumin <3.0 mg/dL, or Geriatric Nutritional Risk Index (GNRI) <98. The study endpoints were all-cause and cardiovascular mortality.

RESULTS

A total of 131 354 participants were identified and categorized according to the chronic kidney disease stage based on eGFR. Compared with the reference eGFR of 60-89 mL/min/1.73 m(2), the overall and cardiovascular mortality risks were markedly high in the groups with eGFR of <30 mL/min/1.73 m(2) [overall: adjusted hazard ratio (aHR), 1.86; 95% confidence interval (CI), 1.72-2.00; cardiovascular: aHR, 1.87; 95% CI, 1.60-2.19] and ≥90 mL/min/1.73 m(2) (overall: aHR, 1.23; 95% CI, 1.13-1.34; cardiovascular: aHR, 1.28; 95% CI, 1.06-1.54). In the absence of MICS, high eGFR was associated with lower mortality risk (aHR, 0.71; 95% CI, 0.62-0.80), and the U-shaped relationship disappeared. Subgroup analyses produced consistent results.

CONCLUSIONS

MICS could influence the association observed between high eGFR and mortality in older people, particularly in those with low body mass index, albumin level, GNRI, and very low serum creatinine level.

Lean body mass change over 6 years is associated with dietary leucine intake in an older Danish population

Higher protein intake, and particularly higher leucine intake, is associated with attenuated loss of lean body mass (LBM) over time in older individuals. Dietary leucine is thought to be a key mediator of anabolism. This study aimed to assess this relationship over 6 years among younger and older adult Danes. Dietary leucine intake was assessed at baseline and after 6 years in men and women, aged 35-65 years, participating in the Danish cohort of the WHO-MONICA (Multinational MONItoring of trends and determinants in CArdiovascular disease) study (n 368). Changes in LBM over the 6 years were measured by bioelectrical impedance using equations developed for this Danish population. The association between leucine and LBM changes was examined using multivariate linear regression and ANCOVA analyses adjusted for potential confounders. After adjustment for baseline LBM, sex, age, energy intake and physical activity, leucine intake was associated with LBM change in those older than 65 years (n 79), with no effect seen in those younger than 65 years. Older participants in the highest quartile of leucine intake (7·1 g/d) experienced LBM maintenance, whereas lower intakes were associated with LBM loss over 6 years (for trend: β=0·434, P=0·03). Sensitivity analysis indicated no effect modification of sex or the presence of CVD. Greater leucine intake in conjunction with adequate total protein intake was associated with long-term LBM retention in a healthy older Danish population. This study corroborates findings from laboratory investigations in relation to protein and leucine intakes and LBM change. A more diverse and larger sample is needed for confirmation of these results.

Effects of dietary protein intake on body composition changes after weight loss in older adults: a systematic review and meta-analysis

CONTEXT

The impact of dietary protein on body composition changes after older adults purposefully lose weight requires systematic evaluation

OBJECTIVE

: This systematic review and meta-analysis assessed the effects of protein intake (< 25% vs ≥ 25% of energy intake or 1.0 g/kg/d) on energy restriction-induced changes in body mass, lean mass, and fat mass in adults older than 50 years.

DATA SOURCES

PubMed, Cochrane, Scopus, and Google Scholar were searched using the keywords "dietary proteins," "body composition," "skeletal muscle," and "muscle strength."

STUDY SELECTION

Two researchers independently screened 1542 abstracts.

DATA EXTRACTION

Information was extracted from 24 articles.

DATA SYNTHESIS

Twenty randomized control trials met the inclusion criteria.

CONCLUSION

Older adults retained more lean mass and lost more fat mass during weight loss when consuming higher protein diets.

Prediction and validation of DXA-derived appendicular lean soft tissue mass by ultrasound in older adults

The purpose of this study was to develop regression-based prediction equations for estimating dual-energy X-ray absorptiometry (DXA)-derived appendicular lean soft tissue mass (aLM) using ultrasound and to investigate the validity of these equations in 102 Caucasian adults aged 50 to 76 years. The subjects were randomly separated into two groups: 71 in the model-development group (41 men and 30 women) and 31 in the cross-validation group (18 men and 13 women). aLM was measured using a DXA, and muscle thickness (MT) was measured using ultrasound at 9 sites. Stepwise linear regression analysis was used to determine predictive models for DXA-derived aLM from MT variables, sex, and age. A number of ultrasound prediction equations for estimation of aLM were developed and then cross-validated in a subsample of older adults. The results indicated that ultrasound MT and MT × height can be used to accurately and reliably estimate DXA-derived aLM in older Caucasian adults.

The mechanistic and ergogenic effects of phosphatidic acid in skeletal muscle

Skeletal muscle mass plays a vital role in locomotion, whole-body metabolic health, and is a positive predictor of longevity. It is well established the mammalian target of rapamycin (mTOR) is a central regulator of skeletal muscle protein turnover. The pursuit to find novel nutrient compounds or functional food sources that possess the ability to activate mTOR and promote skeletal muscle protein accretion has been on going. Over the last decade, a key role has been proposed for the phospholipid phosphatidic acid (PA) in mTOR activation. Mechanical load-induced (i.e., resistance exercise) intramuscular PA can directly bind to and activate mTOR. In addition, PA provided exogenously in cell culture heightens mTOR activity, albeit indirectly. Thus, endogenously generated PA and exogenous provision of PA appear to act through distinct mechanisms that converge on mTOR and, potentially, may amplify muscle protein synthesis. In support of this notion, limited evidence from humans suggests that resistance exercise training combined with oral supplemental PA enhances strength gains and muscle hypertrophy. However, the precise mechanisms underpinning the augmented muscle remodelling response with supplemental PA remain elusive. In this review, we will critically examine available evidence from cell cultures and animal and human experimental models to provide an overview of the mechanisms through which endogenous and exogenous PA may act to promote muscle anabolism, and discuss the potential for PA as a therapeutic tool to maintain or restore skeletal muscle mass in the context of ageing and disease.

More than healthy bones: a review of vitamin D in muscle health

Vitamin D has known importance to bone health including calcium and phosphate homeostasis and appears to have a role in skeletal muscle health as well. Cases of vitamin D deficiency and insufficiency have been associated with poor muscle health. While the exact effects and mechanism of action remains controversial, current data lean towards insufficient vitamin D playing a role in musculoskeletal pain, sarcopenia, myopathy, falls and indirectly via cerebellar and cognitive dysfunction. Sophisticated experimental techniques have allowed detection of the vitamin D receptor (VDR) on skeletal muscle and cerebellar tissue, which if validated in further large studies, could confirm the mechanism of vitamin D in these associations. While further study is required, vitamin D repletion can have a substantial impact on muscle as well as bone health.

Presarcopenia and sarcopenia in hip-fracture women: prevalence and association with ability to function in activities of daily living

BACKGROUND AND AIMS

Sarcopenia staging systems have been proposed, but little is known on their application in hip-fracture patients. Our aim was to assess the prevalence of presarcopenia and sarcopenia and their association with ability to function in activities of daily living in hip-fracture women.

METHODS

We investigated white women (N = 138 of 149) who were consecutively admitted to a rehabilitation hospital because of their first hip fracture. In each woman, we measured appendicular lean mass (aLM) by dual-energy X-ray absorptiometry, at a median of 18 days after hip fracture occurrence. On the same day, we assessed grip strength with a handheld dynamometer. Functional autonomy was assessed by the Barthel Index. We used the European Working Group on Sarcopenia in Older People (EWGSOP) definition to calculate the prevalence of presarcopenia and sarcopenia, taking into account both aLM/height(2) and handgrip strength. Gait speed was not considered, because of the recent hip fracture.

RESULTS

Twenty-three (17 %) of the 138 women fulfilled the diagnostic criteria for presarcopenia whereas 80 (58 %) were sarcopenic. The women with presarcopenia were younger, healthier and with higher Barthel Index scores (median 65 vs. 55; interquartile range 60-75 and 50-60, respectively; p < 0.001) than those with sarcopenia. Significant differences in Barthel Index scores at the time of assessment (but not at the end of the rehabilitation course) persisted after multiple adjustments (p < 0.001).

CONCLUSIONS

The prevalence of presarcopenia and sarcopenia was high in hip-fracture women. Presarcopenic women had higher ability to function in activities of daily living than sarcopenic women.

Understanding and reducing disability in older adults following critical illness

OBJECTIVE

To review how disability can develop in older adults with critical illness and to explore ways to reduce long-term disability following critical illness.

DATA SOURCES

We searched PubMed, CINAHL, Web of Science and Google Scholar for studies reporting disability outcomes (i.e., activities of daily living, instrumental activities of daily living, and mobility activities) and/or cognitive outcomes among patients treated in an ICU who were 65 years or older. We also reviewed the bibliographies of relevant citations to identify additional citations.

STUDY SELECTION

We identified 19 studies evaluating disability outcomes in critically ill patients who were 65 years and older.

DATA EXTRACTION

Descriptive epidemiologic data on disability after critical illness.

DATA SYNTHESIS

Newly acquired disability in activities of daily living, instrumental activities of daily living, and mobility activities was commonplace among older adults who survived a critical illness. Incident dementia and less severe cognitive impairment were also highly prevalent. Factors related to the acute critical illness, ICU practices, such as heavy sedation, physical restraints, and immobility, as well as aging physiology, and coexisting geriatric conditions can combine to result in these poor outcomes.

CONCLUSIONS

Older adults who survive critical illness have physical and cognitive declines resulting in disability at greater rates than hospitalized, noncritically ill and community dwelling older adults. Interventions derived from widely available geriatric care models in use outside of the ICU, which address modifiable risk factors including immobility and delirium, are associated with improved functional and cognitive outcomes and can be used to complement ICU-focused models such as the ABCDEs.

The pathogenetic bases of sarcopenia

Aging is accompanied by involuntary loss of skeletal muscle mass, strength and function, called sarcopenia. The mechanisms underlying the development of sarcopenia are not completely understood and most likely multi-factorial, but significant progress has been made over the past few years to identify some of the major contributors. Besides life style-related factors, as diet and physical activity, sarcopenia seems to be also determined by hormonal dysregulation, chronic inflammatory status, ectopic adipose tissue accumulation, neurological and vascular changes associated with aging. The present mini-review focused on the basic factors that primarily impact muscle homeostasis in older subjects. A better understanding of cellular mechanism leading to sarcopenia is required to establish evidence-based intervention in order to prevent onset of symptoms associated with sarcopenia and to extend the time free from disability in older adults.

Sarcopenia: evaluation of different diagnostic criteria and its association with muscle strength and functional capacity

INTRODUCTION: Sarcopenia has been associated with increased morbidity and mortality in older people. However, there is still no consensus about the best diagnostic criteria for it. OBJECTIVE: This study aimed to evaluate different diagnostic criteria of sarcopenia and their relationship with muscle strength and functional capacity. METHODS: A cross-sectional study was carried out in Santa Maria-RS, Brazil. Body composition was measured by dual-energy X-ray absorptiometry (DXA). Physical performance was evaluated by the Timed-get-up-and-go test (TGUG). Muscle strength was measured with a handgrip dynamometer. The proposed criteria of sarcopenia were evaluated as follows: A) appendicular lean mass index (aLM/ht2), cutoffs 5.5 kg/m2, 2SD, 10th percentile, and 20th percentile of young reference; B) a linear regression model was used to adjust appendicular lean mass (aLM) for both height and fat mass, cutoff 20th percentile of elderly. RESULTS: In total, 104 women agreed to participate in the research, 39 young (20 to 40 years) and 65 elderly (over 60 years). The prevalence of sarcopenia varied from 0% to 17.2% according to the diagnostic criteria. Regarding muscle strength, the aLM/ht2 cutoff 10th percentile was the criterion with greater area under the ROC curve. However, there were no criteria with an area under the ROC curve greater than 0.5 when TGUG was the outcome. The reclassification showed that the criterion B reclassified 66.7% with normal grip strength as sarcopenic. CONCLUSION: Of these criteria, aLM/ht2 cutoff 10th percentile had stronger correlation with muscle strength.

Sarcopenia: a predictor of mortality and the need for early diagnosis and intervention

The term sarcopenia refers to the loss of muscle mass that occurs with aging. Sarcopenia is defined by the European Working Group on Sarcopenia in Older People (EWGSOP) as low muscle mass and low muscle function (strength and performance). Its prevalence varies depending on the definition used for it, but estimates propose a loss of approximately 8 % per decade until the age of 70 years; afterwards, the loss increases and ranges from 13 to 24 % per decade. Irrespective of how sarcopenia is defined, both low muscle mass and poor muscle strength are highly prevalent and important risk factors for disability and increased mortality in individuals as they age. In this review, we address age-related muscle loss and the risk factors of mortality, emphasizing the need for early diagnosis and intervention.

Protein concentration and mitochondrial content in the gastrocnemius predicts mortality rates in patients with peripheral arterial disease

OBJECTIVE

This study evaluated the hypothesis that protein concentration and mitochondrial content in gastrocnemius biopsies from patients with peripheral arterial disease (PAD) predict mortality rates.

BACKGROUND

PAD patients experience advancing myopathy characterized by mitochondrial dysfunction, myofiber degradation, and fibrosis in their ischemic legs, along with increased mortality rates.

METHODS

Samples from the gastrocnemius of PAD patients were used for all analyses. Protein concentration was normalized to muscle wet weight, and citrate synthase activity (standard measure of mitochondrial content in cells) was normalized to muscle wet weight and protein concentration. Protein and citrate synthase data were grouped into tertiles and 5-year, all-cause mortality for each tertile was determined with Kaplan-Meier curves and compared by the modified Peto-Peto test. A Cox-regression model for each variable controlled for the effects of clinical characteristics.

RESULTS

Of the 187 study participants, 46 died during a mean follow-up of 23.0 months. Five-year mortality rate was highest for patients in the lowest tertile of protein concentration. Mortality was lowest for patients in the middle tertile of citrate synthase activity when normalized to either muscle wet weight or protein concentration. The mortality hazard ratios (HRs) from the Cox analysis were statistically significant for protein concentration normalized to muscle wet weight (lowest vs middle tertile; HR = 2.93; P = 0.008) and citrate synthase normalized to protein concentration (lowest vs middle tertile; HR = 4.68; P = 0.003; and lowest vs highest tertile; HR = 2.36; P = 0.027).

CONCLUSIONS

Survival analysis of a contemporaneous population of PAD patients identifies protein and mitochondrial content of their gastrocnemius as predictors of mortality rate.

The Impact of Different Diagnostic Criteria on the Prevalence of Sarcopenia in Healthy Elderly Participants and Geriatric Outpatients

BACKGROUND

A consensus on the diagnostic criteria for sarcopenia, a common syndrome in the elderly, has not been reached yet. Prevalence rates vary between studies due to the use of different criteria encompassing different measures, correction factors and cutoff points.

OBJECTIVE

This study compared prevalence rates of sarcopenia using nine sets of diagnostic criteria applied in two different elderly populations.

METHODS

The study population encompassed 308 healthy elderly participants (152 males, 156 females; mean age 74 years) and 123 geriatric outpatients (54 males, 69 females; mean age 81 years). Diagnostic criteria included relative muscle mass, absolute muscle mass, muscle strength and physical performance.

RESULTS

Prevalence rates of sarcopenia varied between 0 and 15% in healthy elderly participants and between 2 and 34% in geriatric outpatients.

CONCLUSION

This study clearly demonstrates the dependency of sarcopenia prevalence rates on the applied diagnostic criteria.

Body composition and all-cause mortality in subjects older than 65 y

BACKGROUND

A low or high body mass index (BMI) has been associated with increased mortality risk in older subjects without taking fat mass index (FMI) and fat-free mass index (FFMI) into account. This information is essential because FMI is modulated through different healthcare strategies than is FFMI.

OBJECTIVE

We aimed to determine the relation between body composition and mortality in older subjects.

DESIGN

We included all adults ≥65 y old who were living in Switzerland and had a body-composition measurement by bioelectrical impedance analysis at the Geneva University Hospitals between 1990 and 2011. FMI and FFMI were divided into sex-specific quartiles. Quartile 1 (i.e., the reference category) corresponded to the lowest FMI or FFMI quartile. Mortality data were retrieved from the hospital database, the Geneva death register, and the Swiss National Cohort until December 2012. Comorbidities were assessed by using the Cumulative Illness Rating Scale.

RESULTS

Of 3181 subjects included, 766 women and 1007 men died at a mean age of 82.8 and 78.5 y, respectively. Sex-specific Cox regression models, which were used to adjust for age, BMI, smoking, ambulatory or hospitalized state, and calendar time, showed that body composition did not predict mortality in women irrespective of whether comorbidities were taken into account. In men, risk of mortality was lower with FFMI in quartiles 3 and 4 [HR: 0.78 (95% CI: 0.62, 0.98) and 0.64 (95% CI: 0.49, 0.85), respectively] but was not affected by FMI. When comorbidities were adjusted for, FFMI in quartile 4 (>19.5 kg/m(2)) still predicted a lower risk of mortality (HR: 0.72; 95% CI: 0.54, 0.96).

CONCLUSIONS

Low FFMI is a stronger predictor of mortality than is BMI in older men but not older women. FMI had no impact on mortality. These results suggest potential benefits of preventive interventions with the aim of maintaining muscle mass in older men. This trial was registered at clinicaltrials.gov as NCT01472679.

Validity of ultrasound prediction equations for total and regional muscularity in middle-aged and older men and women

To test the validity of published equations, 79 Caucasian adults (40 men and 39 women) aged 50-78 y had muscle thickness (MT) measured by ultrasound at nine sites of the body. Fat-free mass (FFM), lean soft tissue mass (LM) and total muscle mass (TMM) were estimated from MT using equations previously published in the literature. Appendicular LM (aLM) was estimated using dual-energy X-ray absorptiometry (DXA) and this method served as the reference criterion. There were strong correlations (range r = 0.85-0.94) between DXA-derived aLM and estimated FFM, leg LM or TMM. Total error between DXA-derived aLM and TMM (∼2 kg) was lower compared with the three other selected equations (6-10 kg). A Bland-Altman plot revealed that there was no systematic bias between aLM and TMM; however, the other three equations included systematic error. Our results suggest that an ultrasound equation for TMM is appropriate and useful for evaluating skeletal muscle mass in the body.

Frailty status can predict further lean body mass decline in older adults

OBJECTIVES

To assess whether frailty is a risk factor for skeletal muscle mass decline in community-dwelling elderly people.

DESIGN

Prospective observational cohort study.

SETTING

Seongnam, Gyeongi Province, Korea.

PARTICIPANTS

Community-dwelling Koreans aged 65 and older (n = 341).

MEASUREMENTS

Bioimpedance analysis (BIA) was used to measure body composition at baseline and 5 years later. Laboratory examination and comprehensive geriatric assessment were performed at both times. Lean mass index (LMI) was defined as total body lean mass/height(2). A decrease of more than 5% in the LMI was considered to be significant. Frailty status was defined using the Cardiovascular Health Study criteria.

RESULTS

LMI decline occurred in 196 (54.1%) subjects during the follow-up period (5.0 ± 0.7 years). Baseline LMI was highest in robust (17.6 ± 1.8 kg/m(2), n = 126), lower prefrail (17.0 ± 1.7 kg/m(2), n = 185), and lowest in frail (16.7 ± 1.3 kg/m(2), n = 30) subjects (P < .001). Frailty status was associated with LMI decline at 5-year follow-up (robust 0.81 ± 0.78 kg/m(2), prefrail 1.00 ± 0.92 kg/m(2), frail 1.35 ± 0.85 kg/m(2), P < .001). This effect of frailty on LMI decline persisted after adjusting for covariables (P = .02). The risk of significant LMI decline was 2.9 times as great in frail elderly adults as in those who were robust even after adjusting for covariates (95% confidence interval = 1.01-8.55).

CONCLUSION

Frailty status was found to be independently associated with subsequent LMI decline in community-dwelling older adults.

Body-composition predictors of mortality in women aged ≥ 75 y: data from a large population-based cohort study with a 17-y follow-up

BACKGROUND

The role of body composition as a risk factor for death remains controversial in older persons.

OBJECTIVE

We determined the role of body-composition variables in mortality in older women.

DESIGN

Longitudinal analyses were performed in a prospective cohort study of older women. Participants were 4574 community-dwelling women aged ≥ 75 y at the baseline visit (between January 1992 and April 1994). Several body-composition variables were assessed by using anthropometric measures and dual-energy X-ray absorptiometry at the baseline visit. The main outcome was overall mortality. Body-composition variables were body mass index (BMI; in kg/m(2)), hip circumference, waist circumference, waist-to-hip ratio, fat mass/height(2), lean mass/height(2), percentage of fat mass, percentage of lean mass, and the lean mass:fat mass ratio.

RESULTS

The mean (± SD) age at baseline was 80.2 ± 3.8 y. During the 17.7 y (IQR: 17.2-18.1 y) of follow-up, 2876 women died. U-shaped in crude analyses and reversed J-shaped relations in adjusted analyses between BMI, hip and waist circumferences, fat mass/height(2), and risk of death were shown. Adjusted risk of death was significantly higher in participants with BMI ≤ 24.6 and fat mass/height(2) ≤ 8.2 kg/m(2). There was a negative linear association between fat mass (%) and risk of death: a 10% increase in fat mass was associated with a 12% reduction of mortality risk (adjusted HR: 0.88; 95% CI: 0.84, 0.92; P < 0.001). Linear and statistically significant relations were shown between lean mass/height(2) and risk of death in crude but not adjusted analyses.

CONCLUSIONS

Risk of mortality was consistently higher in older women with low adiposity. No lean mass indicator was associated with risk of death. Clinicians should be alerted by low adiposity in older women.

Sarcopenia, sarcopenic obesity and mortality in older adults: results from the National Health and Nutrition Examination Survey III

BACKGROUND

Sarcopenia is defined as the loss of skeletal muscle mass and quality, which accelerates with aging and is associated with functional decline. Rising obesity prevalence has led to a high-risk group with both disorders. We assessed mortality risk associated with sarcopenia and sarcopenic obesity in elders.

METHODS

A subsample of 4652 subjects ≥60 years of age was identified from the National Health and Nutrition Examination Survey III (1988-1994), a cross-sectional survey of non-institutionalized adults. National Death Index data were linked to this data set. Sarcopenia was defined using a bioelectrical impedance formula validated using magnetic resonance imaging-measured skeletal mass by Janssen et al. Cutoffs for total skeletal muscle mass adjusted for height(2) were sex-specific (men: ≤5.75 kg/m(2); females ≤10.75 kg/m(2)). Obesity was based on % body fat (males: ≥27%, females: ≥38%). Modeling assessed mortality adjusting for age, sex, ethnicity (model 1), comorbidities (hypertension, diabetes, congestive heart failure, osteoporosis, cancer, coronary artery disease and arthritis), smoking, physical activity, self-reported health (model 2) and mobility limitations (model 3).

RESULTS

Mean age was 70.6±0.2 years and 57.2% were female. Median follow-up was 14.3 years (interquartile range: 12.5-16.1). Overall prevalence of sarcopenia was 35.4% in women and 75.5% in men, which increased with age. Prevalence of obesity was 60.8% in women and 54.4% in men. Sarcopenic obesity prevalence was 18.1% in women and 42.9% in men. There were 2782 (61.7%) deaths, of which 39.0% were cardiovascular. Women with sarcopenia and sarcopenic obesity had a higher mortality risk than those without sarcopenia or obesity after adjustment (model 2, hazard ratio (HR): 1.35 (1.05-1.74) and 1.29 (1.03-1.60)). After adjusting for mobility limitations (model 3), sarcopenia alone (HR: 1.32 ((1.04-1.69) but not sarcopenia with obesity (HR: 1.25 (0.99-1.58)) was associated with mortality. For men, the risk of death with sarcopenia and sarcopenic obesity was nonsignificant in both model-2 (HR: 0.98 (0.77-1.25), and HR: 0.99 (0.79-1.23)) and model 3 (HR: 0.98 (0.77-1.24) and HR: 0.98 (0.79-1.22)).

CONCLUSIONS

Older women with sarcopenia have an increased all-cause mortality risk independent of obesity.

Site-specific thigh muscle loss as an independent phenomenon for age-related muscle loss in middle-aged and older men and women

The purpose of this study was to examine the relationships between dual-energy X-ray absorptiometry (DXA)-determined appendicular lean mass (aLM) and ultrasound-measured thigh muscle thickness (MTH) ratio and between aLM or thigh MTH ratio and zigzag walking performance. Eighty-one middle-aged and older adults (41 men and 40 women) aged 50 to 74 years volunteered for the study. Approximately two thirds of the subjects (34 men and 17 women) carried out regular sports activity (at least >2 times a week) including running and cycling exercise. MTH was measured using B-mode ultrasound at two sites on the anterior (A50) and posterior (P50) aspects of the mid-thigh. A50:P50 MTH ratio was calculated to evaluate site-specific thigh muscle loss. aLM and percent body fat were also determined using a DXA. Men had lower body fat and higher aLM than women. Anterior and posterior thigh MTH as well as A50:P50 MTH ratio was higher in men than in women. Zigzag walking time was faster in men than in women. Anterior and posterior thigh MTH was positively (p < 0.001) correlated to aLM and aLM index in men and women. However, A50:P50 MTH ratio was not significantly correlated with aLM and aLM index in both sexes. There was no significant correlation between aLM index and zigzag walking time in men and women. A50:P50 MTH ratio was inversely (p < 0.05) correlated to zigzag walking time in both men and women. Our results suggest that thigh MTH ratio is independent of age-related muscle mass loss detected by aLM.

Age-related site-specific muscle wasting of upper and lower extremities and trunk in Japanese men and women

The purpose of this study was to examine the age-related site-specific muscle loss of the upper and lower extremities and trunk in men and women. Japanese nonobese adults aged 20-79 (n = 1559, 52 % women) had muscle thickness (MTH) measured by ultrasound at nine sites on the anterior and posterior aspects of the body. An MTH ratio located in the anterior and posterior aspects of the upper arm, upper leg, lower leg, and trunk was calculated. Site-specific muscle loss was defined as a ratio of MTH > 2 standard deviations below the mean for young adults in each segment. Age was inversely correlated (p < 0.001) to upper-leg MTH ratio in men (r = -0.463) and women (r = -0.541). Age was correlated positively to upper-arm MTH ratio and inversely to trunk MTH ratio in men (r = 0.191 and r = -0.238, both p < 0.001) and women (r = 0.102, p = 0.004 and r = -0.446, p < 0.001). Weak correlations were observed between age and lower-leg MTH ratios in men (r = 0.015, p = 0.682) and women (r = 0.086, p = 0.015). The prevalence of site-specific upper-leg muscle loss showed an age-related increasing pattern in men (6 % for ages 30-39, 21 % for ages 50-59, and 38 % for ages 70-79) and women (15 % for ages 30-39, 32 % for ages 50-59, and 50 % for ages 70-79). For other segments, however, the prevalence rate of site-specific muscle loss was relatively low throughout the age groups in men and women, although higher rates were observed in the older group. These results suggest that the anterior/posterior MTH ratio of the upper leg may be useful in providing an earlier diagnosis for site-specific muscle loss.

Sarcopenia and cardiovascular risk in physically active adult and elderly women

The purpose of this study was to assess the prevalence of sarcopenia and its association with risk factors for cardiovascular diseases (CVD) in non-sedentary women. Study participants were 124 women (control group (CG) n = 33; 24.5 ± 2.9 years and study group (SG) n = 91; 61.9 ± 8.7 years). Anthropometric measurements, blood parameters, body composition (DXA), anthropometric indices and questionnaire answers were analyzed. Sarcopenia was considered as a standard deviation below mean values for young people, corresponding to 7.3 kg/m2 and classifying 34.1% of SG as sarcopenic. Prevalence of risk for CVD considered low, moderate and high was 21%, 60% and 19%, respectively. Logistic regression showed no relationship between sarcopenia and risk factors for CVD, except for body mass index as a protection factor. There was a tendency for sarcopenia to assume associations as risk factor for variables smoking, triglycerides, obesity, abdominal fat, and Framingham Risk Score and as a protection factor for variable physical activity level.

Diagnostic criteria for sarcopenia and physical performance

Relative and absolute muscle mass and muscle strength are used as diagnostic criteria for sarcopenia. We aimed to assess which diagnostic criteria are most associated with physical performance in 180 young (18-30 years) and 281 healthy old participants (69-81 years) of the European study MYOAGE. Diagnostic criteria included relative muscle mass (total or appendicular lean mass (ALM) as percentage of body mass), absolute muscle mass (ALM/height squared and total lean mass), knee extension torque, and handgrip strength. Physical performance comprised walking speed, Timed Up and Go test (TUG), and in a subgroup physical fitness. Diagnostic criteria for sarcopenia and physical performance were standardized, and the associations were analyzed using linear regression models stratified by age category, with adjustments for age, gender, and country. In old participants, relative muscle mass was associated with faster walking speed, faster TUG, and higher physical fitness (all p < 0.001). Absolute muscle mass was not associated with physical performance. Knee extension torque and handgrip strength were associated with faster walking speed (both p ≤ 0.003). Knee extension torque was associated with TUG (p = 0.001). Knee extension torque and handgrip strength were not associated with physical fitness. In young participants, there were no significant associations between diagnostic criteria for sarcopenia and physical performance, except for a positive association between relative muscle mass and physical fitness (p < 0.001). Relative muscle mass, defined as lean mass or ALM percentage, was most associated with physical performance. Absolute muscle mass including ALM/height squared was not associated with physical performance. This should be accounted for when defining sarcopenia.

Effects of vitamin D in skeletal muscle: falls, strength, athletic performance and insulin sensitivity

Accompanying the high rates of vitamin D deficiency observed in many countries, there is increasing interest in the physiological functions of vitamin D. Vitamin D is recognized to exert extra-skeletal actions in addition to its classic roles in bone and mineral homeostasis. Here, we review the evidence for vitamin D's actions in muscle on the basis of observational studies, clinical trials and basic research. Numerous observational studies link vitamin D deficiency with muscle weakness and sarcopaenia. Randomized trials predominantly support an effect of vitamin D supplementation and the prevention of falls in older or institutionalized patients. Studies have also examined the effect of vitamin D in athletic performance, both inferentially by UV radiation and directly by vitamin D supplementation. Effects of vitamin D in muscle metabolic function, specifically insulin sensitivity, are also addressed in this review. At a mechanistic level, animal studies have evaluated the roles of vitamin D and associated minerals, calcium and phosphate, in muscle function. In vitro studies have identified molecular pathways by which vitamin D regulates muscle cell signalling and gene expression. This review evaluates evidence for the various roles of vitamin D in skeletal muscle and discusses controversies that have made this a dynamic field of research.

Diagnostic criteria for sarcopenia relate differently to insulin resistance

Skeletal muscle is important in insulin-stimulated glucose uptake. Sarcopenia is, therefore, a possible risk factor for insulin resistance. Currently, different diagnostic criteria for sarcopenia include low muscle mass, muscle strength, and walking speed. We assessed these muscle characteristics in relation to insulin resistance in nondiabetics. This cross-sectional study included 301 nondiabetics, mean age 65.9 years. Area under curve (AUC) calculations of insulin and glucose from a 2-h oral glucose tolerance test (OGTT) and homeostasis model assessment of insulin resistance (HOMA-IR) were used as measures of insulin resistance. Muscle characteristics were relative muscle mass (total or appendicular lean mass (ALM) as percentage of body mass), absolute muscle mass (ALM/height(2) and total lean mass), handgrip strength, and walking speed. All muscle characteristics were standardized and analyzed in linear regression models, stratified by gender. For both males and females, relative muscle mass was inversely associated with AUC insulin, AUC glucose, and HOMA-IR (ALM percentage all p ≤ 0.004). Absolute muscle mass was positively associated with AUC insulin and HOMA-IR (ALM/height(2) all p < 0.001) but not with AUC glucose. Adjustments for fat mass attenuated aforementioned associations. There were no associations between handgrip strength and insulin resistance. Walking speed was inversely associated with AUC insulin in males (p = 0.032). The association between muscle characteristics and insulin resistance was strongest for relative muscle mass. Diagnostic criteria for sarcopenia relate differently to insulin resistance. The role of muscle tissue as an internal glucose-regulating organ is better reflected by relative muscle mass than by absolute muscle mass, muscle strength, or walking speed.

Reversal of myoblast aging by tocotrienol rich fraction posttreatment

Skeletal muscle satellite cells are heavily involved in the regeneration of skeletal muscle in response to the aging-related deterioration of the skeletal muscle mass, strength, and regenerative capacity, termed as sarcopenia. This study focused on the effect of tocotrienol rich fraction (TRF) on regenerative capacity of myoblasts in stress-induced premature senescence (SIPS). The myoblasts was grouped as young control, SIPS-induced, TRF control, TRF pretreatment, and TRF posttreatment. Optimum dose of TRF, morphological observation, activity of senescence-associated β-galactosidase (SA-β-galactosidase), and cell proliferation were determined. 50 μg/mL TRF treatment exhibited the highest cell proliferation capacity. SIPS-induced myoblasts exhibit large flattened cells and prominent intermediate filaments (senescent-like morphology). The activity of SA-β-galactosidase was significantly increased, but the proliferation capacity was significantly reduced as compared to young control. The activity of SA-β-galactosidase was significantly reduced and cell proliferation was significantly increased in the posttreatment group whereas there was no significant difference in SA-β-galactosidase activity and proliferation capacity of pretreatment group as compared to SIPS-induced myoblasts. Based on the data, we hypothesized that TRF may reverse the myoblasts aging through replenishing the regenerative capacity of the cells. However, further investigation on the mechanism of TRF in reversing the myoblast aging is needed.

The Official Positions of the International Society for Clinical Densitometry: body composition analysis reporting

Dual-energy x-ray absorptiometry (DXA) measurements of body composition increasingly are used in the evaluation of clinical disorders, but there has been little guidance on how to effectively report these measures. Uniformity in reporting of body composition measures will aid in the diagnosis of clinical disorders such as obesity, sarcopenia, and lipodystrophy. At the 2013 International Society for Clinical Densitometry Position Development Conference on body composition, the reporting section recommended that all DXA body composition reports should contain parameters of body mass index, bone mineral density, BMC, total mass, total lean mass, total fat mass, and percent fat mass. The inclusion of additional measures of adiposity and lean mass are optional, including visceral adipose tissue, appendicular lean mass index, android/gynoid percent fat ratio, trunk to leg fat mass ratio, lean mass index, and fat mass index. Within the United States, we recommend the use of the National Health and Nutrition Examination Survey 1999-2004 body composition dataset as an age-, gender-, and race-specific reference and to calibrate BMC in 4-compartment models. Z-scores and percentiles of body composition measures may be useful for clinical interpretation if methods are used to adjust for non-normality. In particular, DXA body composition measures may be useful for risk-stratification of obese and sarcopenic patients, but there needs to be validation of thresholds to define obesity and sarcopenia. To summarize, these guidelines provide evidence-based standards for the reporting and clinical application of DXA-based measures of body composition.

Omega-3 fatty acids and changes in LBM: alone or in synergy for better muscle health?

Myopenia or muscle wasting due to ageing, chronic disease, and various medical interventions has been associated with increased mortality, morbidity, and poorer physical function. Attempts through nutrient and exercise interventions have been made to prevent this deterioration. In addition, while a measure of lean body mass (LBM) is associated with health outcomes, LBM function may be a better prognostic tool. Long-chain omega-3 fatty acids (LCn-3s) are nutrients that may mitigate LBM losses in noncancer populations. The purpose of this review is to determine whether LCn-3s have a role in LBM sparing in noncancer populations, to establish a minimum dose and duration of LCn-3s that will result in LBM change, and to summarise the potential effects of LCn-3s on LBM function when combined with an anabolic stimulus. Overall, in noncancer populations, LCn-3s have limited utility in sparing LBM during energy balance, energy restriction, or in conjunction with aerobic exercise. Further investigations are required to determine the appropriate dose and duration of LCn-3s for optimal LBM function. Finally, compelling evidence exists for LCn-3s in conjunction with an anabolic stimulus to improve LBM function and quality. Functionality of LBM tissue is an important outcome for population health, and LCn-3s show some promise, albeit pending further study.

Sarcopenia, a neurogenic syndrome?

Sarcopenia is an aging-associated condition, which is currently characterized by the loss of muscle mass and muscle strength. However, there is no consensus regarding its characterization hitherto. As the world older adult population is on the rise, the impact of sarcopenia becomes greater. Due to the lack of effective treatments, sarcopenia is still a persisting problem among the global older adults and should not be overlooked. As a result, it is vital to investigate deeper into the mechanism underlying the pathogenesis of sarcopenia in order to develop more effective therapeutic interventions and to inscribe a more uniform characterization. The etiology of sarcopenia is currently found to be multifactorial, and most of the pharmacological researches are focused on the muscular factors in aging. Although the complete mechanism underlying the development of sarcopenia is still waiting to be elucidated, we propose in this article that the primary trigger of sarcopenia may be neurogenic in origin based on the intimate relationship between the nervous and muscular system, namely, the motor neuron and its underlying muscle fibers. Both of them are affected by the cellular environment and their physiological activity.

Mortality as an adverse outcome of sarcopenia

Sarcopenia has an important impact in elderly. Recently the European Working Group on Sarcopenia in Older People (EWGSOP) defined sarcopenia as the loss of muscle mass plus low muscle strength or low physical performance. Lack of clinical sounding outcomes (ie external validity), is one of the flaws of this algorithm. The aim of our study was to determine the association of sarcopenia and mortality in a group of Mexican elderly. A total of 345 elderly were recruited in Mexico City, and followed up for three years. The EWGSOP algorithm was integrated by: gait speed, grip strength and calf circumference. Other covariates were assessed in order to test the independent association of sarcopenia with mortality. Of the 345 subjects, 53.3% were women; with a mean age of 78.5 (SD 7) years. During the three year follow-up a total of 43 (12.4%) subjects died. Age, cognition, ADL, IADL, health self-perception, ischemic heart disease and sarcopenia were associated in the bivariate analysis with survival. Negative predictive value for sarcopenia regarding mortality was of 90%. Kaplan-Meier curves along with their respective log-rank test were significant for sarcopenia. The components of the final Cox-regression multivariate model were age, ischemic heart disease, ADL and sarcopenia. Adjusted HR for age was 3.24 (CI 95% 1.55-6.78 p 0.002), IHD 5.07 (CI 95% 1.89-13.59 p 0.001), health self-perception 5.07 (CI 95% 1.9-13.6 p 0.001), ADL 0.75 (CI 95% 0.56-0.99 p 0.048) and sarcopenia 2.39 (CI 95% 1.05-5.43 p 0.037).