Estimation of skeletal muscle mass by bioelectrical impedance analysis

Study of Mental Activity and Regular Training (SMART) in at risk individuals: a randomised double blind, sham controlled, longitudinal trial

Background

The extent to which mental and physical exercise may slow cognitive decline in adults with early signs of cognitive impairment is unknown. This article provides the rationale and methodology of the first trial to investigate the isolated and combined effects of cognitive training (CT) and progressive resistance training (PRT) on general cognitive function and functional independence in older adults with early cognitive impairment: Study of Mental and Regular Training (SMART). Our secondary aim is to quantify the differential adaptations to these interventions in terms of brain morphology and function, cardiovascular and metabolic function, exercise capacity, psychological state and body composition, to identify the potential mechanisms of benefit and broader health status effects.

Methods

SMART is a double-blind randomized, double sham-controlled trial. One hundred and thirty-two community-dwelling volunteers will be recruited. Primary inclusion criteria are: at risk for cognitive decline as defined by neuropsychology assessment, low physical activity levels, stable disease, and age over 55 years. The two active interventions are computerized CT and whole body, high intensity PRT. The two sham interventions are educational videos and seated calisthenics. Participants are randomized into 1 of 4 supervised training groups (2 d/wk × 6 mo) in a fully factorial design. Primary outcomes measured at baseline, 6, and 18 months are the Alzheimer's Disease Assessment Scale (ADAS-Cog), neuropsychological test scores, and Bayer Informant Instrumental Activities of Daily Living (B-IADLs). Secondary outcomes are psychological well-being, quality of life, cardiovascular and musculoskeletal function, body composition, insulin resistance, systemic inflammation and anabolic/neurotrophic hormones, and brain morphology and function via Magnetic Resonance Imaging (MRI) and Spectroscopy (fMRS).

Discussion

SMART will provide a novel evaluation of the immediate and long term benefits of CT, PRT, and combined CT and PRT on global cognitive function and brain morphology, as well as potential underlying mechanisms of adaptation in older adults at risk of further cognitive decline.

Trial Registration

Australia and New Zealand Clinical Trials Register (ANZCTR): ANZCTRN12608000489392

[Frailty and dependence in Albacete (FRADEA study): reasoning, design and methodology]

OBJECTIVE

To obtain a cohort of subjects of equal to or greater than 70 years, representative of a Spanish urban population, to estimate the prevalence of frailty and follow it up over time to analyse associated factors.

MATERIAL AND METHODS

A prospective, population-based cohort study. From a population of 18,137 elderly persons, a representative sample of 1172 was randomly stratified, of which 993 (84.7%) agreed to take part. The variables collected were; sociodemographic, comorbidity, functional (n=825), cognitive, affective and quality of life. On the patients who agreed, body composition was determined by bioimpedance analysis (n=557), basal metabolic rate by indirect calorimetry (n=450) and a blood sample was obtained for biomarkers (n=859). Frailty was defined by the presence of 3 or more Fried criteria: unintentional weight loss, low energy, exhaustion, slow walking, and low physical activity. The cohort will be followed up over time until the death of the subjects.

RESULTS

Mean age 79.4 (SD 6.4) years, with 601 (60.5%) women. A total of 21.3% were institutionalised; 16.9% were frail, 48.5% pre-frail, 21.3% non-frail, and 12.8% did not have the 3 criteria to be able to determine their state, of which 9.5% had moderate-severe incapacity, which would increase the prevalence of frailty to 26.4%.

CONCLUSIONS

A FRADEA cohort has been constructed, representative of an urban population in Spain. The prevalence of frailty in the cohort was 16.9%.

[The emergent role of sarcopenia: Preliminary Report of the Observatory of Sarcopenia of the Spanish Society of Geriatrics and Gerontology]

Sarcopenia is a common and prominent geriatric syndrome, of major interest for daily clinical practice of professionals working with older people. The number of affected individuals and its relation with disability, frailty, many chronic diseases, lifestyle and adverse outcomes are extremely relevant for geriatric care. Moreover, biological changes that lead to the loss of muscle mass and strength are intrinsically related to the mechanisms of aging. It is not therefore surprising that research in this field is growing exponentially in recent years, and sarcopenia has been placed in recent years in the forefront of research in geriatric medicine and gerontology. The Spanish Society of Geriatrics and Gerontology has recently created an Observatory of Sarcopenia, which aims to promote educational and research activities in this field. The first activity of the Observatory has been to offer the Spanish speaking scientific community a review of the current status of sarcopenia, that may allow unifying concepts and fostering interest in this promising field of geriatrics.

Dietary, anthropometric, and biochemical determinants of plasma high-density lipoprotein-cholesterol in free-living adults

The level of high-density lipoprotein is thought to be critical in inhibiting lesion formation as well as reducing the lipid load of preexisting atherosclerotic lesions. With the aim of determining the main determinants of plasma HDL-cholesterol (HDL-c) in free-living adults, 997 individuals (52.3 ± 10 years, 67% females) were selected for a descriptive cross-sectional study. The used data corresponded to the baseline obtained from participants clinically selected for a lifestyle modification program. Covariables of clinical, anthropometry, food intake, aerobic fitness, and plasma biochemistry were analyzed against plasma HDL-c either as continuous or categorized variables. After adjustments for age, gender, and BMI the excess of abdominal fat along with high carbohydrate-energy intake and altered plasma triglycerides were the stronger predictors of reduced plasma HDL-c. In conclusion lifestyle interventions aiming to normalize abdominal fatness and plasma triglycerides are recommended to restore normal levels of HDL-c in these free-living adults.

Body composition predicted with a Bayesian network from simple variables

The relative contributions of fat-free mass (FFM) and fat mass (FM) to body weight are key indicators for several major public health issues. Predictive models could offer new insights into body composition analysis. A non-parametric equation derived from a probabilistic Bayesian network (BN) was established by including sex, age, body weight and height. We hypothesised that it would be possible to assess the body composition of any subject from easily accessible covariables by selecting an adjusted FFM value within a reference dual-energy X-ray absorptiometry (DXA) measurement database (1999-2004 National Health and Nutrition Examination Survey (NHANES), n 10 402). FM was directly calculated as body weight minus FFM. A French DXA database (n 1140) was used (1) to adjust the model parameters (n 380) and (2) to cross-validate the model responses (n 760). French subjects were significantly different from American NHANES subjects with respect to age, weight and FM. Despite this different population context, BN prediction was highly reliable. Correlations between BN predictions and DXA measurements were significant for FFM (R2 0·94, P < 0·001, standard error of prediction (SEP) 2·82 kg) and the percentage of FM (FM%) (R2 0·81, P < 0·001, SEP 3·73 %). Two previously published linear models were applied to the subjects of the French database and compared with BN predictions. BN predictions were more accurate for both FFM and FM than those obtained from linear models. In addition, BN prediction generated stochastic variability in the FM% expressed in terms of BMI. The use of such predictions in large populations could be of interest for many public health issues.

Optimal management of sarcopenia

Sarcopenia is the progressive generalized loss of skeletal muscle mass, strength, and function which occurs as a consequence of aging. With a growing older population, there has been great interest in developing approaches to counteract the effects of sarcopenia, and thereby reduce the age-related decline and disability. This paper reviews (1) the mechanisms of sarcopenia, (2) the diagnosis of sarcopenia, and (3) the potential interventions for sarcopenia. Multiple factors appear to be involved in the development of sarcopenia including the loss of muscle mass and muscle fibers, increased inflammation, altered hormonal levels, poor nutritional status, and altered renin-angiotensin system. The lack of diagnostic criteria to identify patients with sarcopenia hinders potential management options. To date, pharmacological interventions have shown limited efficacy in counteracting the effects of sarcopenia. Recent evidence has shown benefits with angiotensin-converting enzyme inhibitors; however, further randomized controlled trials are required. Resistance training remains the most effective intervention for sarcopenia; however, older people maybe unable or unwilling to embark on strenuous exercise training programs.

Sarcopenia, cardiopulmonary fitness, and physical disability in community-dwelling elderly people

BACKGROUND

Sarcopenia refers to the loss of skeletal muscle mass with aging. It is believed to be associated with functional impairment and physical disability.

OBJECTIVE

The purposes of this study were: (1) to compare the physical activity, muscle strength (force-generating capacity), cardiopulmonary fitness, and physical disability in community-dwelling elderly people with sarcopenia, borderline sarcopenia, and normal skeletal muscle mass in Taiwan and (2) to test the hypothesis that sarcopenia is associated with physical disability and examine whether the association is mediated by decreased muscle strength or cardiopulmonary fitness.

DESIGN

This was a cross-sectional investigation.

METHODS

Two hundred seventy-five community-dwelling elderly people (148 men, 127 women) aged > or =65 years participated in the study. The participants were recruited from communities in the district of Zhongzheng, Taipei. Predicted skeletal muscle mass was estimated using a bioelectrical impedance analysis equation. The skeletal muscle mass index (SMI) was calculated by dividing skeletal muscle mass by height squared. Physical disability was assessed using the Groningen Activity Restriction Scale. Physical activity was assessed using a 7-day recall physical activity questionnaire. Cardiopulmonary fitness was assessed using a 3-minute step test, and grip strength was measured to represent muscle strength.

RESULTS

Cardiopulmonary fitness was significantly lower in elderly people with sarcopenia than in those with normal SMIs. Grip strength and daily energy expenditure (kcal/kg/day) were not significantly different between the participants with sarcopenia and those with normal SMIs. The odds ratio for physical disability between the participants with sarcopenia and those with normal SMIs was 3.03 (95% confidence interval=1.21-7.61). The odds ratio decreased and the significant difference diminished after controlling for cardiopulmonary fitness.

LIMITATIONS

A causal relationship between sarcopenia and physical activity, cardiopulmonary fitness, and physical disability cannot be established because of the cross-sectional nature of study design.

CONCLUSIONS

Sarcopenia was associated with physical disability in elderly men. The association between sarcopenia and physical disability was mediated to a large extent by decreased cardiopulmonary fitness.

Sarcopenia: European consensus on definition and diagnosis: Report of the European Working Group on Sarcopenia in Older People

The European Working Group on Sarcopenia in Older People (EWGSOP) developed a practical clinical definition and consensus diagnostic criteria for age-related sarcopenia. EWGSOP included representatives from four participant organisations, i.e. the European Geriatric Medicine Society, the European Society for Clinical Nutrition and Metabolism, the International Association of Gerontology and Geriatrics-European Region and the International Association of Nutrition and Aging. These organisations endorsed the findings in the final document. The group met and addressed the following questions, using the medical literature to build evidence-based answers: (i) What is sarcopenia? (ii) What parameters define sarcopenia? (iii) What variables reflect these parameters, and what measurement tools and cut-off points can be used? (iv) How does sarcopenia relate to cachexia, frailty and sarcopenic obesity? For the diagnosis of sarcopenia, EWGSOP recommends using the presence of both low muscle mass + low muscle function (strength or performance). EWGSOP variously applies these characteristics to further define conceptual stages as 'presarcopenia', 'sarcopenia' and 'severe sarcopenia'. EWGSOP reviewed a wide range of tools that can be used to measure the specific variables of muscle mass, muscle strength and physical performance. Our paper summarises currently available data defining sarcopenia cut-off points by age and gender; suggests an algorithm for sarcopenia case finding in older individuals based on measurements of gait speed, grip strength and muscle mass; and presents a list of suggested primary and secondary outcome domains for research. Once an operational definition of sarcopenia is adopted and included in the mainstream of comprehensive geriatric assessment, the next steps are to define the natural course of sarcopenia and to develop and define effective treatment.

The BELFRAIL (BFC80+) study: a population-based prospective cohort study of the very elderly in Belgium

Background

In coming decades the proportion of very elderly people living in the Western world will dramatically increase. This forthcoming "grey epidemic" will lead to an explosion of chronic diseases. In order to anticipate booming health care expenditures and to assure that social security is funded in the future, research focusing on the relationship between chronic diseases, frailty and disability is needed. The general aim of the BELFRAIL cohort study (BF_C80+) is to study the dynamic interaction between health, frailty and disability in a multi-system approach focusing on cardiac dysfunction and chronic heart failure, lung function, sarcopenia, renal insufficiency and immunosenescence.

Methods/Design

The BF_C80+ is a prospective, observational, population-based cohort study of subjects aged 80 years and older in three well-circumscribed areas of Belgium. In total, 29 general practitioner (GP) centres were asked to include patients aged 80 and older. Only three exclusion criteria were used: severe dementia, in palliative care and medical emergency. Two sampling methods for the recruitment of patients were used. Between November 2, 2008 and September 15, 2009, 567 subjects were included in the BF_C80+ study. Every study participant was invited to undergo four study visits. The GP recorded background variables and medical history and performed a detailed anamnesis and clinical examination. The clinical research assistant performed an extensive examination including performance testing, questionnaires and technical examinations. Echocardiography was performed at home by a cardiologist. A blood sample was collected in the morning. Follow-up reporting of hard outcome measures including mortality, hospitalization and morbidity was organized. A second data collection is planned after 18 months.

Discussion

The BF_C80+ was designed to acquire a better understanding of the epidemiology and pathophysiology of chronic diseases in the very elderly and to study the dynamic interaction between health, frailty and disability in a multi-system approach. The wide variety of dimensions investigated in the BF_C80+ will enable us not only to investigate in depth the relationship between the different physiological systems but also to initiate new research questions based on this unique database of community-dwelling elderly.

Low expression of long-chain acyl-CoA dehydrogenase in human skeletal muscle

PURPOSE

Long-chain acyl-CoA dehydrogenase (LCAD) is a mitochondrial flavoenzyme thought to be one of the major enzymes responsible for the first step of long-chain fatty acid (LCFA) beta-oxidation. Surprisingly, recent studies have shown LCAD is hardly detectable in human tissues such as liver and heart. Skeletal muscle is the largest organ in the body in terms of mass, and accounts for the majority of LCFA oxidation, especially during exercise. The purpose of this study was to investigate the expression levels of LCAD in human skeletal muscle.

METHODS

Muscle biopsies were obtained from the vastus lateralis of healthy athletic men and women, and examined for mRNA abundance, protein content, and enzyme activity of LCAD. We compared LCAD content with that of very-long chain acyl-CoA dehydrogenase (VLCAD) and medium chain acyl-CoA dehydrogenase (MCAD); two mitochondrial beta-oxidation enzymes that have overlapping chain-length specificity to that of LCAD. LCAD protein content and enzyme activity were also examined in enriched mitochondrial protein fractions. As controls, LCAD presence in skeletal muscle was compared to human heart, liver, and mouse skeletal muscle.

RESULTS

The mRNA presence of LCAD in human skeletal muscle is significantly less than VLCAD and MCAD (0.08+/-0.01 vs 7.3+/-0.5 vs 2.4+/-0.2 respectively, P<or=0.0001). LCAD protein was undetectable in human muscle homogenates, and coordinately LCAD enzyme activity was undetectable in enriched mitochondrial samples.

CONCLUSION

LCAD is minimally expressed in human skeletal muscle and likely does not play a significant role in LCFA oxidation.

Sarcopenia exacerbates obesity-associated insulin resistance and dysglycemia: findings from the National Health and Nutrition Examination Survey III

Background

Sarcopenia often co-exists with obesity, and may have additive effects on insulin resistance. Sarcopenic obese individuals could be at increased risk for type 2 diabetes. We performed a study to determine whether sarcopenia is associated with impairment in insulin sensitivity and glucose homeostasis in obese and non-obese individuals.

Methodology

We performed a cross-sectional analysis of National Health and Nutrition Examination Survey III data utilizing subjects of 20 years or older, non-pregnant (N = 14,528). Sarcopenia was identified from bioelectrical impedance measurement of muscle mass. Obesity was identified from body mass index. Outcomes were homeostasis model assessment of insulin resistance (HOMA IR), glycosylated hemoglobin level (HbA1C), and prevalence of pre-diabetes (6.0≤ HbA1C<6.5 and not on medication) and type 2 diabetes. Covariates in multiple regression were age, educational level, ethnicity and sex.

Principal Findings

Sarcopenia was associated with insulin resistance in non-obese (HOMA IR ratio 1.39, 95% confidence interval (CI) 1.26 to 1.52) and obese individuals (HOMA-IR ratio 1.16, 95% CI 1.12 to 1.18). Sarcopenia was associated with dysglycemia in obese individuals (HbA1C ratio 1.021, 95% CI 1.011 to 1.043) but not in non-obese individuals. Associations were stronger in those under 60 years of age. We acknowledge that the cross-sectional study design limits our ability to draw causal inferences.

Conclusions

Sarcopenia, independent of obesity, is associated with adverse glucose metabolism, and the association is strongest in individuals under 60 years of age, which suggests that low muscle mass may be an early predictor of diabetes susceptibility. Given the increasing prevalence of obesity, further research is urgently needed to develop interventions to prevent sarcopenic obesity and its metabolic consequences.

Sarcopenia: European consensus on definition and diagnosis: Report of the European Working Group on Sarcopenia in Older People

The European Working Group on Sarcopenia in Older People (EWGSOP) developed a practical clinical definition and consensus diagnostic criteria for age-related sarcopenia. EWGSOP included representatives from four participant organisations, i.e. the European Geriatric Medicine Society, the European Society for Clinical Nutrition and Metabolism, the International Association of Gerontology and Geriatrics-European Region and the International Association of Nutrition and Aging. These organisations endorsed the findings in the final document. The group met and addressed the following questions, using the medical literature to build evidence-based answers: (i) What is sarcopenia? (ii) What parameters define sarcopenia? (iii) What variables reflect these parameters, and what measurement tools and cut-off points can be used? (iv) How does sarcopenia relate to cachexia, frailty and sarcopenic obesity? For the diagnosis of sarcopenia, EWGSOP recommends using the presence of both low muscle mass + low muscle function (strength or performance). EWGSOP variously applies these characteristics to further define conceptual stages as 'presarcopenia', 'sarcopenia' and 'severe sarcopenia'. EWGSOP reviewed a wide range of tools that can be used to measure the specific variables of muscle mass, muscle strength and physical performance. Our paper summarises currently available data defining sarcopenia cut-off points by age and gender; suggests an algorithm for sarcopenia case finding in older individuals based on measurements of gait speed, grip strength and muscle mass; and presents a list of suggested primary and secondary outcome domains for research. Once an operational definition of sarcopenia is adopted and included in the mainstream of comprehensive geriatric assessment, the next steps are to define the natural course of sarcopenia and to develop and define effective treatment.

Estimativa da massa muscular esquelética em mulheres idosas: validade da impedância bioelétrica

O presente estudo tem como objetivos: a) verificar a concordância entre os métodos da impedância bioelétrica (BIA) e da absortometria radiológica de dupla energia (DXA) para a estimativa da massa muscular esquelética (MME); e b) analisar o poder preditivo de variáveis antropométricas e da BIA para a predição da MME em idosas. Foram avaliadas 120 mulheres (60 a 81 anos), residentes na região Sul do Brasil. Mensuraram-se as variáveis antropométricas (massa corporal e estatura); a resistência e hidratação dos tecidos livres de gordura foram medidas pela técnica da BIA tetrapolar (Biodinamics - BF-310), e pela DXA de corpo inteiro (Lunar Prodigy DF + 14319 Radiation e software 7.52.002 DPX-L). A diferença entre os métodos foi verificada pelo teste t pareado, análise dos resíduos e o coeficiente de correlação. O valor preditivo das variáveis antropométricas e de BIA foi verificado pela regressão linear múltipla, adotando nível de significância de p < 0,05. Não houve diferença estatística entre os métodos para a estimativa da MME (p > 0,01). Observou-se que a BIA subestimou em média 0,8kg (IC95%: -3,7; 2,0kg) a MME, quando comparada com a DXA. Foi observada alta correlação entre os métodos (r² = 0,75; p < 0,01). A análise de regressão demonstrou que a variável da razão entre a estatura ao quadrado e a resistência (EST²/R) explica 80% da variação da MME, quando ajustada para massa corporal e idade, e essa relação é independente das variáveis de gordura corporal, hidratação dos tecidos magros e índice de massa corporal. Assim, nota-se que a equação da BIA, aqui testada, é válida para a estimativa da MME em mulheres idosas e seu valor pode ser mais bem predito pelo modelo de regressão proposto a partir da medida de EST²/R ajustada para a massa corporal e idade.

[Aging changes in muscle mass of Japanese]

AIM

The purpose of this study is To examine the influence of age on muscle mass in a Japanese population for health promotion.

METHODS

Subjects were 4,003 community-dwelling Japanese men and women. We employed four-frequency bioelectrical impedance analysis to estimate upper and lower limbs, trunk and whole body muscle mass.

RESULTS

Men showed significantly more muscle mass in all parts of the body compared to women. There was a curvilinear relationship between age and muscle mass in both men and women. For all parts of the body, the slope of the regression line between age and muscle mass was greater in men than women. The changes in muscle mass with advancing age were different in each part of the body. In the upper limbs, there was little change with advancing age in both men and women. In the lower limbs, the decrease in muscle mass began after two decades, with the reduction in this muscle mass the greatest of all parts of the body with advancing age. In the trunk, the slope of the regression line increased from the second to the fifth decade, after which the slope decreased.

CONCLUSIONS

These findings indicated that lower limb muscle mass was the first to begin to decrease and also showed the greatest decrease. For health promotion, it was seen as important to maintain muscle mass from at least middle age, with particular emphasis on the lower limbs.

Sex differences in global mRNA content of human skeletal muscle

Women oxidize more fat as compared to men during endurance exercise and several groups have shown that the mRNA content of selected genes related to fat oxidation are higher in women (e.g. hormone sensitive lipase, β-hydroxyacyl-CoA dehydrogenase, CD36). One of the possible mechanisms is that women tend to have a higher area percentage of type I skeletal muscle fibers as compared with men. Consequently, we hypothesized that sex would influence the basal mRNA and protein content for genes involved in metabolism and the determination of muscle fiber type. Muscle biopsies from the vastus lateralis were collected from healthy men and women. We examined mRNA content globally using Affymetrix GeneChips, and selected genes were examined and/or confirmed by RT-PCR. Furthermore, we examined protein content by Western blot analysis. Stringent gene array analysis revealed 66 differentially expressed genes representing metabolism, mitochondrial function, transport, protein biosynthesis, cell proliferation, signal transduction pathways, transcription and translation. Stringent gene array analysis and RT-PCR confirmed that mRNA for; acyl-coenzyme A acyltransferase 2 (ACAA2), trifunctional protein β (HADHB), catalase, lipoprotein lipase (LPL), and uncoupling protein-2 (UCP-2) were higher in women. Targeted gene analysis revealed that myosin heavy chain I (MHCI), peroxisome proliferator-activated receptor (PPAR)δ were higher in women compared with men. Surprisingly, there were no significant sex based differences in protein content for HADHB, ACAA2, catalase, PPARδ, and MHC1. In conclusion, the differences in the basal mRNA content in resting skeletal muscle suggest that men and women are transcriptionally “primed” for known physiological differences in metabolism however the mechanism behind sex differences in fiber type remains to be determined.

Sarcopenic-obesity and cardiovascular disease risk in the elderly

OBJECTIVES

To determine: 1) whether sarcopenic-obesity is a stronger predictor of cardiovascular disease (CVD) than either sarcopenia or obesity alone in the elderly, and 2) whether muscle mass or muscular strength is a stronger marker of CVD risk.

DESIGN

Prospective cohort study.

PARTICIPANTS

Participants included 3366 community-dwelling older (>or= 65 years) men and women who were free of CVD at baseline.

MEASUREMENTS

Waist circumference (WC), bioimpedance analysis, and grip strength were used to measure abdominal obesity, whole-body muscle mass, and muscular strength, respectively. Subjects were classified as normal, sarcopenic, obese, or sarcopenic-obese based on measures of WC and either muscle mass or strength. Participants were followed for 8 years for CVD development and proportional hazard regression models were used to compare risk estimates for CVD in the four groups after adjusting for age, sex, race, income, smoking, alcohol, and cognitive status.

RESULTS

Compared with the normal group, CVD risk was not significantly elevated within the obese, sarcopenic, or sarcopenic-obese groups as determined by WC and muscle mass. When determined by WC and muscle strength, CVD risk was not significantly increased in the sarcopenic or obese groups, but was increased by 23% (95% confidence interval: 0.99-1.54, P=0.06) within the sarcopenic-obese group.

CONCLUSION

Sarcopenia and obesity alone were not sufficient to increase CVD risk. Sarcopenic-obesity, based on muscle strength but not muscle mass, was modestly associated with increased CVD risk. These findings imply that strength may be more important than muscle mass for CVD protection in old age.

Sarcopenia in nursing home residents

The age-associated loss of muscle mass and muscle strength described by the term sarcopenia is highly relevant for functionality among nursing home residents. Nevertheless, the scientific literature concentrating on sarcopenia in this population is scarce. For practical reasons, common definitions of this entity, which rely on dual energy x-ray absorptiometry (DEXA) and bioimpedance analysis (BIA), cannot be applied in this setting. Anthropometric measurements like arm muscle circumference and calf circumference seem to be most suitable. Handgrip may be used as an alternative. Prevalence data show a wide range but are mostly high. There is a close association of the degree of sarcopenia with dependence among residents. The pathophysiology of sarcopenia in this population is strongly influenced by comorbidity and often there is significant overlap with the cachexia syndrome. At present, physical exercise is regarded to be the most promising therapeutic option, with resistance training being superior to endurance programs. Physical exercise has been successful even among Alzheimer patients and physically restrained residents. It has to be accompanied by the provision of adequate and diverse meals based on individual energy and nutrient requirements. Special attention should be paid to the treatment of vitamin D deficiency if present. New therapeutic options include Whole Body Vibration, oral supplements with essential amino acids and leucine, ACE-inhibitors, and cytokine-modifying drugs.

Nutritional status evaluation and survival in haemodialysis patients in one centre from Romania

BACKGROUND

Protein-energy wasting is a common complication and an important predictive factor for mortality in chronic dialysis patients. Therefore, nutritional status needs to be regularly assessed in these patients, by using several methods, and, if malnutrition is present, its possible causes should be thoroughly searched for and properly treated.

MATERIAL AND METHODS

In 149 prevalent haemodialysis patients (82 men, mean age 53.9 +/- 13.7 years), we evaluated the nutritional status by anthropometrics [post-dialysis height (H), body weight (BW), body mass index (BMI), mid-arm circumference (MAC), tricipital skin-fold thickness (TST), mid-arm muscle circumference (MAMC), corrected mid-arm muscle area (cMAMA) and three-category subjective global assessment score (SGA)], biochemical tests [protein equivalent of nitrogen appearance (nPNA), and pre-dialysis serum albumin, creatinine, total cholesterol, bicarbonate and haemoglobin (Hb) levels] and bioelectrical impedance analysis (BIA) to estimate body composition [percent body fat (%BF), fat-free mass (%FFM), body cell mass (%BCM), extracellular mass (%ECM) and the phase angle (PhA)].

RESULTS

Age was found to be positively correlated with BMI (P = 0.001), and inversely correlated with %BCM (P = 0.013). Patients with A-category SGA were significantly younger (50.1 versus 63.7 years) than those with B-category SGA. Patients with diabetes had lower %BCM (32.9 versus 35.9%; P = 0.035) and PhA (5.5 versus 6.9 degrees ; P = 0.0007) than those without diabetes. The presence of heart failure was associated with significantly reduced nPNA (1.17 versus 1.34 g/kg day; P = 0.014), MAMC (22.0 versus 23.6 cm(2); P = 0.041), %BCM (33.0 versus 36.1; P = 0.021), PhA (5.8 versus 7.0 degrees ; P = 0.031), serum albumin (39.7 versus 42.4 g/l; P = 0.013) and serum creatinine (8.1 versus 9.4 mg/dl; P = 0.010), and with a higher percent of B-category SGA (47.8% versus 22.6%; P = 0.019). Eleven deaths (7.4%) occurred during the follow-up period. Among general factors, age >or= 55, the presence of diabetes, and dialysis vintage <2 years were associated with significantly reduced survival. Among nutritional factors, B-category SGA, nPNA <1.2 g/kg day, %BF <15% and PhA <6 degrees significantly predicted mortality in both Kaplan-Meier and Cox analyses. The most important risk factor appeared to be nPNA; for every 0.1 g/kg day increase in nPNA, death risk decreased by 15%.

CONCLUSIONS

In our haemodialysis patients, advancing age, diabetes and heart failure were associated with worse nutritional status, as estimated by anthropometry, biochemical markers and BIA. Age >or=55 years, the presence of diabetes, nPNA <1.2 g/kg day, lower SGA score, %BF <15% and PhA <6 degrees were associated with significantly increased death risk.

Assessment of body composition in dialysis patients by arm bioimpedance compared to MRI and 40K measurements

This study used multi-frequency bioimpedance spectroscopy (BIS) of the arm and whole body to estimate muscle mass (MM) and subcutaneous adipose tissue (SAT) in 31 hemodialysis (HD) patients comparing these results with magnetic resonance imaging (MRI) and body potassium ((40)K) as gold standards. Total body and arm MM (MM(MRI)) and SAT (SAT(MRI)) were measured by MRI. All measurements were made before dialysis treatment. Regression models with the arm (aBIS) and whole body (wBIS) resistances were established. Correlations between gold standards and the BIS model were high for the arm SAT (r(2) = 0.93, standard error of estimate (SEE) = 3.6 kg), and whole body SAT (r(2) = 0.92, SEE = 3.5 kg), and for arm MM (r(2) = 0.84, SEE = 2.28 kg) and whole body MM (r(2) = 0.86, SEE = 2.28 kg). Total body MM and SAT can be accurately predicted by arm BIS models with advantages of convenience and portability, and it should be useful to assess nutritional status in HD patients.

Low relative skeletal muscle mass indicative of sarcopenia is associated with elevations in serum uric acid levels: findings from NHANES III

BACKGROUND

Sarcopenia may be related to increases in reactive oxygen species formation and inflammation, both of which are associated with elevations in serum uric acid.

OBJECTIVE

To test the hypothesis that a reduced skeletal muscle mass index, indicative of sarcopenia, is related to elevations in uric acid.

DESIGN

Cross-sectional analysis of nationally representative data.

SETTING

Third National Health and Nutrition Examination Survey, 1988-1994.

PATIENTS

7544 men and women 40 years of age and older who had uric acid, skeletal muscle mass, and select covariate information.

MEASUREMENTS

Skeletal muscle mass assessment was based on a previously published equation including height, BIA-resistance, gender, and age. Absolute skeletal muscle mass was calculated for all study population individuals and compared against the sex-specific mean for younger adults. Serum uric acid data were gathered from the NHANES laboratory file.

RESULTS

A logistic regression analysis revealed that elevations in serum uric acid are significantly related to sarcopenia status. For every unit (mg/dL) increase in uric acid, the odds ratio of manifesting a skeletal muscle mass index at least one standard deviation below the reference mean was 1.12. Participants in the highest grouping (> 8 mg/dL) of serum uric acid concentration had 2.0 times the odds of manifesting sarcopenia compared to the lowest grouping (< 6 mg/dL) (p < 0.01) after adjusting for the additional covariates.

LIMITATIONS

This study design was limited in its cross-sectional nature. Potential selection, measurement, and recall bias may have occurred, and methodology used to classify sarcopenia status based on skeletal muscle mass index is not validated.

CONCLUSION

This observation provides support for the theory that elevations in uric acid may lead to sarcopenia, although the proposed mechanism needs further experimental support.

Derivation of a new equation for estimating creatinine clearance by using fat-free mass and serum creatinine concentration in Korean patients with type 2 diabetes mellitus

AIMS

Equations to predict creatinine clearance (Ccr) or glomerular filtration rate have limitations in applying to a wide range of ethnicities with different fat-free mass (FFM). We aimed to determine the serum creatinine (Scr) concentrations that indicate renal insufficiency and formulate a new equation to estimate Ccr by a function of FFM in Korean type 2 diabetic patients.

METHODS

Ccr was measured in 283 type 2 diabetic patients by 24-h urine collection. Receiver operating characteristic (ROC) curve was used to determine the Scr concentration corresponding to a Ccr of 60 mL min(-1) x 1.73 m(-2). A new equation to predict Ccr was derived by using Scr and FFM.

RESULTS

The Scr concentration corresponding to a Ccr of 60 mL min(-1) x 1.73 m(-2) was 1.15 mg/dL in men and 0.95 mg/dL in women. The regression equation estimating the Ccr was expressed as (1.72 x FFM-0.23 x age)/Scr, and it showed a good correlation with the measured Ccr (r=0.718, P<0.001).

CONCLUSIONS

Scr concentrations indicating renal insufficiency in the Korean patients were considerably lower than those in Caucasians. The equation derived in this study would be more useful in Korean or other Asian type 2 diabetic patients.

The effects of running 1,200 km within 17 days on body composition in a female ultrarunner-Deutschlandlauf 2007

We describe the changes of body composition in the female overall winner of the Deutschlandlauf 2007 over 17 stages from the northeast to the southwest of Germany with average daily running stages of 70.9 km to cover the total distance of 1,200 km. Determined by bioelectrical impedance analysis, body mass (BM) increased, percent body fat (% BF) decreased, and percent body water as well as lean body mass (LBM) increased. Skeletal muscle mass and % BF as determined by an anthropometric method showed no changes. This data show, that this female runner achieved an excellent performance and that it is possible for a woman to beat all the men. This type of analysis provides a unique opportunity to gain insight into the physiological changes during multiday running in ultraendurance athletes.

The physical functional capacity of frail elderly persons undergoing ambulatory rehabilitation is related to their nutritional status

OBJECTIVES

To estimate the prevalence of malnutrition in frail elders undergoing rehabilitation and the association between their nutritional status and physical function.

DESIGN

Observational study of new participants undergoing ambulatory rehabilitation.

SETTING

Two Geriatric Day Hospitals (GDH) in Montreal, Quebec.

PARTICIPANTS

121 women and 61 men.

INTERVENTION

Evaluation of nutritional status, body composition and physical function.

MEASUREMENTS

The nutritional status was assessed with a composite index based on anthropometric measurements and serum albumin, as well as using the Mini Nutritional Assessment (MNA) questionnaire. Patients were classified as well-nourished, having mild/at risk of malnutrition or malnourished. Body composition was estimated by bioimpedance and handgrip strength and gait speed by standard methods.

RESULTS

13% of patients were found to be mildly malnourished, whereas 6% were malnourished. Malnourished patients were older and had worse cognition, lower BMI, and % body fat (all p<0.05). Malnourished patients and those with mild malnutrition had lower weight, triceps skinfold thickness, muscle and fat mass (all, p<0.003). Handgrip strength was different according to the nutritional status (p=0.034) and correlated with muscle mass (r=0.65, p<0.001). MNA classified 53% of patients as being at risk whereas 3% were malnourished and it correlated with gait speed (r=0.26, p=0.001).

CONCLUSION

There is a high prevalence of patients in GDH at risk or with mild malnutrition. Being malnourished was associated with worse physical performance, which suggests that a nutritional intervention may be of benefit in improving their physical function.

Prevalence of sarcopenia estimated using a bioelectrical impedance analysis prediction equation in community-dwelling elderly people in Taiwan

OBJECTIVES

To compare a bioelectrical impedance analysis (BIA) prediction equation for estimating skeletal muscle mass (SM) with magnetic resonance imaging (MRI)-measured SM and to investigate the prevalence of sarcopenia in community-dwelling elderly people in Taiwan.

DESIGN

Cross-sectional survey.

SETTING

Communities in the district of Zhongzheng, Taipei.

PARTICIPANTS

Forty-one volunteers (aged 22-90) for BIA equation validation; 302 individuals aged 65 and older and 200 adults aged 18 to 40 for the investigation of the prevalence of sarcopenia.

MEASUREMENTS

Skeletal muscle mass was estimated using a BIA prediction equation and measured using MRI.

RESULTS

No statistical difference between MRI-measured and BIA-derived SM was observed (difference of -0.44 +/- 1.55 kg, P=.08). The prevalence of sarcopenia in was 18.6% in elderly women and 23.6% in elderly men.

CONCLUSION

Estimation of SM using a BIA equation was validated in Taiwanese volunteers. It was confirmed that sarcopenia is an emerging health problem in the aging population in Taiwan.

Validação de equações antropométricas para a estimativa da massa muscular por meio de absortometria radiológica de dupla energia em universitários do sexo masculino

Diferentes equações antropométricas têm sido desenvolvidas e validadas para uso em populações distintas, a partir de modelos multicompartimentais. A absortometria radiológica de dupla energia (DEXA) é uma alternativa multicompartimental de avaliação da composição corporal, ainda pouco utilizada no Brasil para validação e desenvolvimento de equações antropométricas, sobretudo para predição da massa muscular (MM). Assim, o objetivo deste estudo foi validar equações antropométricas para estimativa da MM a partir da DEXA, em universitários brasileiros do sexo masculino. Para tanto, 131 adultos entre 18 e 36 anos (73,9 ± 9,7kg; 177,6 ± 6,4cm; MM = 32,1 ± 3,6kg) foram avaliados por meio da DEXA e de medidas antropométricas (massa corporal, estatura, circunferências e espessura de dobras cutâneas), e analisados mediante utilização de quatro equações preditivas da MM. Foram utilizadas as seguintes análises: estatística descritiva, procedimentos de validação cruzada e análise de concordância (CCI e Bland e Altman). A equação 3 [MM (kg) = E.(0,00744.CBrC² + 0,00088.CCxC² + 0,00441.CPantC²) + 2,4.S - 0,048.Id + R + 7,8] de Lee et al. (Am J Clin Nutr 2000;72:796-803) apresentou validade concorrente, para a avaliação da MM (t = 1,13; r = 0,83; EPE = 2,08; diferença média [d] = 0,21). Além desta, a equação 4, dos mesmos autores [MM (kg) = 0,244.MC + 7,8.E + 6,6.S - 0,098.Id + R - 3,3], com baixos valores de EPE (2,20), erro constante (- 0,72), erro total (2,72) e d (- 0,77) e boas concordâncias (moderada a alta) foi sugerida para utilização na amostra estudada. Novos estudos de validação são sugeridos em amostras diferentes, mediante o uso de DEXA como método de referência. Da mesma forma, sugere-se maior utilização de equações antropométricas para avaliação da MM, sobretudo para o monitoramento das alterações na massa muscular em relação aos processos de crescimento, desenvolvimento e envelhecimento e na avaliação do treinamento físico e esportivo.

Sarcopenia: its assessment, etiology, pathogenesis, consequences and future perspectives

Sarcopenia is a loss of muscle protein mass and loss of muscle function. It occurs with increasing age, being a major component in the development of frailty. Current knowledge on its assessment, etiology, pathogenesis, consequences and future perspectives are reported in the present review. On-going and future clinical trials on sarcopenia may radically change our preventive and therapeutic approaches of mobility disability in older people.

Efeito de um mês de destreinamento sobre a aptidão física relacionada à saúde em programa de mudança de estilo de vida

O exercício físico induz adaptações hemodinâmicas/ventilatórias e neuromusculares que podem ser revertidas com a interrupção do mesmo. O presente estudo teve por objetivo avaliar o efeito do destreinamento sobre a aptidão física relacionada à saúde. Foram avaliados 44 indivíduos de ambos os sexos com idade de 57,6 ± 8,9 anos. O Protocolo de Mudança de Estilo de Vida Mexa-se Pró-Saúde com orientação nutricional e exercícios físicos supervisionados, teve duração de nove meses envolvendo exercícios aeróbicos, de resistência muscular localizada e flexibilidade, com duração de 80 min/sessão, em cinco sessões semanais. Foram selecionados os indivíduos que obtiveram freqüência mínima de 3x/semana. O período de interrupção do treinamento foi de um mês. Foram avaliados peso (kg) e estatura (m) e calculado o Índice de Massa Corporal (IMC-kg/m²) e realizados testes motores para flexibilidade (FLEX), força de membros inferiores (FMI) e superiores (FMS) e consumo máximo de oxigênio (VO2máx.) no início do programa (MI), após nove meses de treinamento (MT) e após pausa de um mês (MD). O tratamento estatístico utilizado foi ANOVA com nível de significância de 5% e o teste de Tukey para a localização das diferenças entre os grupos, quando a mesma foi constatada. Os resultados mostraram que ganhos significativos de 22% e 7% na força de membros inferiores e VO2máx. respectivamente, alcançados com o treinamento foram mantidos após a interrupção do programa por um mês; enquanto que o aumento de 8% na flexibilidade retornou aos níveis basais após o período de destreinamento. Conclui-se que embora mantidos os ganhos de força de membros inferiores e capacidade aeróbica adquiridos, um mês de destreinamento foi suficiente para perder a flexibilidade conquistada.

[Evaluation of the best indicator of muscle mass in community-dwelling elderly persons]

AIM

The purpose of this study was to determine the best way to indicate muscle mass of community-dwelling elderly men and women.

METHODS

We recruited 398 elderly men and women (age range, 61-96, years) who use a community center and live in a metropolitan suburb. We measured appendicular and whole body muscle mass by using bioelectrical impedance analysis and analyzed our results in relation to indicators of physical function. We assessed muscle mass with no adjustment, adjustment by body mass, and adjustment by body height.

RESULTS

In men, appendicular muscle mass adjusted by body mass correlated significantly with 10-m obstacle walking time, and whole body muscle mass adjusted by body mass correlated significantly with all indicators physical function except five chair stands and maximum walking speed. In women, appendicular and whole body muscle mass adjusted by body mass correlated significantly with all indicators of physical function. However, appendicular and whole body muscle mass adjusted by body height were unrelated to indicators of physical function.

CONCLUSIONS

Only whole body muscle mass adjusted by body mass was related to physical function in both men and women. This finding suggests that whole body muscle mass adjusted by body mass is the best indicator of muscle mass in community-dwelling elderly persons.

Plasma hormones, muscle mass and strength in resistance-trained postmenopausal women

OBJECTIVE

To associate changes of body composition, muscle strength (MS) and plasma hormones (PH) in resistance-training protocol in sedentary postmenopausal women (PMW).

DESIGN

This randomized controlled trial, Brazilian 43 PMW (45-70-year-old) able for physical exercises were selected after they have accomplished medical and ethical criteria. They were assigned in two groups: RT, resistance training (n=22); and CT, not trained control (n=21); with supervision sessions of two to three exercise for large and one exercise for smaller groups in three series of 8-12 rep. (60-80%1RM) for each exercise. The training period lasted 16 weeks and was preceded by low-load exercise (40-50%1RM) adaptation period of 4 weeks (3/(times week)). Body weight, height, body mass index (BMI), and composition (BIA) along with fast-PH (FSH, LH, estradiol, cortisol, IGF-1 and testosterone) were assessed before (M0) and after (M16) the 4 weeks period with the MS (1RM) determined also at 8 weeks (M8). The values were correlated by Person's test and the means compared by Student's t-test and ANOVA.

RESULTS

At baseline both groups were similar in age, time of PMW, body composition, MS and fast-PH. However after 16 weeks, RT presented higher BMI (2.1%), IGF-1 (37.8%) and MM gain (1.8+/-0.8 kg) than CT. MM correlated positively with IGF-1 (r=0.45, p<0.05) and MS progressively increased in all exercise greater in pectoral than legs and upper arms.

CONCLUSION

Former sedentary postmenopausal women submitted to resistance training gained MM and MS irrespectively of fat mass changes but significantly associated with IGF-1 increase.

BMI vs. body composition and radiographically defined osteoarthritis of the knee in women: a 4-year follow-up study

OBJECTIVE

To elucidate the role of body mass index (BMI) and knee osteoarthritis (OAK) by evaluating measures of body composition including fat mass and skeletal muscle mass (SMM).

METHODS

Data are from 541 women enrolled in the Michigan Bone Health Study, a longitudinal, population-based study. At visits in 1998 and 2002, radiographs were taken of both knees and were evaluated for the presence of OAK (>or=2 on the Kellgren-Lawrence (K-L) scale). Joint space width (JSW) was measured with electronic calipers. Fat mass and SMM were determined using bioelectrical impedance analysis.

RESULTS

In 2002, the prevalence of OAK was 11% in this population of women whose mean age was 47 years. Fat mass, lean mass, SMM, waist circumference and BMI were greater in women with OAK compared to those without OAK. In multiple variable analyses adjusted for age, fat mass and SMM explained OAK prevalence and increasing OAK severity better than models with BMI; further SMM explained more variation than did fat mass. SMM was positively associated with level of left and right medial JSW while there was no consistent association of JSW and BMI or fat mass.

CONCLUSION

Fat mass and SMM were associated with K-L OAK score and the amount of joint space, with more variation explained by SMM. SMM was highly associated with JSW. Therefore, though obesity, frequently characterized by BMI, is a frequently reported risk factor for OAK, this mis-attribution may mean that interventions that focus on weight loss as treatment for osteoarthritis should be aware that this may negatively impact muscle mass.

Prevalence of sarcopenia in the French senior population

INTRODUCTION

A muscle mass normalized for height2 (MMI) or for body weight (SMI) below 2SD under the mean for a young population defines sarcopenia. This study aimed at setting the cutoffs and the prevalence of sarcopenia in the French elderly population. Another objective was to compare the results obtained with SMI and MMI.

METHODS

Muscle mass was assessed by bioelectrical impedance analysis in 782 healthy adults (< 40 years) to determine skeletal mass index (SMI, muscle mass*100/weight) and muscle mass index (MMI, muscle mass/height2). Prevalence was estimated in 888 middle aged (40-59 years) and 218 seniors (60-78 years). All were healthy people.

RESULTS

For women mean-2SD were 6.2 kg/m2 (MMI) and 26.6% (SMI); for men limits were 8.6 kg/m2 (MMI) and 34.4% (SMI). In middle aged persons a small number of them were identified as sarcopenic. In healthy seniors, 2.8% of women and 3.6% of men were sarcopenic (MMI). The prevalence was 23.6% in women and 12.5% in men with SMI. MMI and SMI identified different sarcopenic populations, leaner subjects for MMI while fatter subjects for SMI.

CONCLUSION

Cutoff values for the French population were defined. Prevalence of sarcopenia was different from that in the US population.

VO(2max) prediction from multi-frequency bioelectrical impedance analysis

Bioelectrical impedance analysis (BIA) has been shown to be highly related to skeletal muscle mass and blood volume, both of which are important determinants of maximal oxygen uptake (VO(2max)). The aim of the present study was therefore to investigate the ability of whole-body and segmental multi-frequency BIA to improve current nonexercise VO(2max) prediction models. Data for VO(2max) (mL min(-1)), anthropometry, self-reported physical activity (PA-R) and BIA were collected in 115 men and women. Multiple linear regression analysis (MLR) was used to develop the most parsimonious prediction model. Segmental BIA was not superior to whole-body measurements. Correlation coefficients between VO(2max) and resistance indices were significantly higher at 500 kHz compared to 50 kHz (p < 0.05). Intracellular resistance index, however, showed the highest correlation with VO(2max) (r = 0.89). After adjusting for age, gender and PA-R, MLR revealed that the inclusion of intracellular resistance index was slightly, but significantly (p < 0.001), superior to models based on anthropometry. Subgroup analyses indicated that the true benefit of BIA might be most prevalent in subjects with particularly low VO(2max) (<2500 mL min(-1)). In short, whole-body BIA marginally improves the accuracy of nonexercise VO(2max) prediction models and its advantage is most pronounced in individuals with particularly low VO(2max).

Applicability of a segmental bioelectrical impedance analysis for predicting the whole body skeletal muscle volume

This study aimed to test the hypothesis that a segmental bioelectrical impedance (BI) analysis can predict whole body skeletal muscle (SM) volume more accurately than a whole body BI analysis. Thirty males (19–34 yr) participated in this study. They were divided into validation ( n = 20) and cross-validation groups ( n = 10). The BI values were obtained using two methods: whole body BI analysis, which determines impedance between the wrist and ankle; and segmental BI analysis, which determines the impedance of every body segment in both sides of the upper arm, lower arm, upper leg and lower leg, and five parts of the trunk. Using a magnetic resonance imaging method, whole body SM volume was determined as a reference (SMVMRI). Simple and multiple regression analyses were applied to (length)2/ Z (BI index) for the whole body and for every body segment, respectively, to develop the prediction equations of SMVMRI. In the validation group, there were no significant differences between the measured and estimated SMV and no systematic errors in either BI analysis. In the cross-validation group, the whole body BI analysis produced systematic errors and resulted in the overestimation of SMVMRI, but the segmental BI analysis was cross-validated. In the pooled data, the segmental BI analysis produced a prediction equation, which involves the BI indexes of the trunk and upper thigh as independent variables, with a SE of estimation of 1,693.8 cm3 (6.1%). Thus the findings obtained here indicated that the segmental BI analysis is superior to the whole body BI analysis for estimating SMVMRI.