Fatigue and the prediction of negative health outcomes: A systematic review with meta-analysis.

INTRODUCTION: Fatigue is a common complaint among older adults. Evidence grows that fatigue is linked to several negative health outcomes. A general overview of fatigue and its relationship with negative health outcomes still lacks in the existing literature. This brings complications for healthcare professionals and researchers to identify fatigue-related health risks. Therefore, this study gives an overview of the prospective predictive value of the main negative health outcomes for fatigue in community-dwelling older adults. METHODS: PubMed, Web of Knowledge and PsycINFO were systematically screened for prospective studies regarding the relationship between fatigue and negative health outcomes resulting in 4595 articles (last search 5th March 2020). Meta-analyses were conducted in RevMan using Odds ratios (ORs), Hazard ratios (HRs) and relative risk ratios (RR) that were extracted from the included studies. Subgroup-analyses were performed based on (1) gender (male/female), (2) length of follow-up and (3) fatigue level (low, medium and high). RESULTS: In total, thirty articles were included for this systematic review and meta-analysis encompassing 152 711 participants (age range 40-98 years), providing information on the relationship between fatigue and health outcomes. The results showed that fatigue is related to an increased risk for the occurrence of all studied health outcomes (range OR 1.299-3.094; HR/RR 1.038-1.471); for example, mortality OR 2.14 [1.74-2.63]; HR/RR 1.44 [1.28-1.62]), the development of disabilities in basic activities of daily living (OR 3.22 [2.05-5.38]), or the occurrence of physical decline (OR 1.42 [1.29-1.57]). CONCLUSION: Overall fatigue increases the risk for developing negative health outcomes. The analyses presented in this study show that fatigue related physical decline occurs earlier than hospitalization, diseases and mortality, suggesting the importance of early interventions.

Exercise Interventions for the Prevention and Treatment of Sarcopenia. A Systematic Umbrella Review.

OBJECTIVES: The aim of this systematic review is to provide an overview of the efficacy of different exercise interventions to counter sarcopenia in older adults. This review will allow the Belgian Society of Gerontology and Geriatrics and other scientific societies to formulate specific exercise recommendations in their Clinical Guidelines for Sarcopenia. DESIGN: We used the method of a systematic umbrella-review. Based on the level of evidence, we formulated specific recommendations for clinical practice. METHODS: Two databases (Pubmed and Web Of Science) were searched systematically and methodological quality of the reviews was assessed. Extracted data was than mapped to an exercise category and an overall synthesis (bottom line statements) was formulated for each of these exercise categories. Subsequently, we assigned a rating of the quality of the evidence supporting each bottom line statement. RESULTS: We identified 14 systematic reviews or meta-analyses, encompassing four exercise categories: resistance training, resistance training + nutritional supplementation, multimodal exercise programmes and bloodflow restriction training. Importantly, very few systematic reviews or meta-analyses clearly mentioned baseline sarcopenia status. There is high quality evidence for a positive and significant effect of resistance training on muscle mass, muscle strength, and physical performance. The added effect of nutritional supplementation for resistance training on muscle function appears limited. Blood flow restriction training is a novel training method that has a significant impact on muscle strength. CONCLUSION: Since sarcopenia is affecting all skeletal muscles in the body, we recommend training the large muscle groups in a total body approach. Although low-intensity resistance training (≤50% 1RM) is sufficient to induce strength gains, we recommend a high-intensity resistance training program (i.e. 80% 1RM) to obtain maximal strength gains. Multimodal exercises and blood flow restriction resistance training may be considered as well.

The operationalization of fatigue in frailty scales: a systematic review.

PURPOSE: To identify the different fatigue items in existing frailty scales. METHODS: PubMed, Web of Knowledge and PsycINFO were systematically screened for frailty scales. 133 articles were included, describing 158 frailty scales. Fatigue items were extracted and categorized in 4 fatigue constructs: "mood state related tiredness", "general feeling of tiredness", "activity based feeling of tiredness" and "resistance to physical tiredness". RESULTS: 120 fatigue items were identified, of which 100 belonged to the construct "general feeling of tiredness" and only 9 to the construct "resistance to physical tiredness". 49,4% of the frailty scales included at least 1 fatigue item, representing 15 ±â€¯9,3% of all items in these scales. Fatigue items have a significantly higher weight in single domain (dominantly physical frailty scales) versus multi domain frailty scales (21 ±â€¯3.2 versus 10.6 ±â€¯9.8%, p=<0,05). CONCLUSION: Fatigue is prominently represented in frailty scales, covering a great diversity in fatigue constructs and underlying pathophysiological mechanisms by which fatigue relates to frailty. Although fatigue items were more prevalent and had a higher weight in physical frailty scales, the operationalization of fatigue leaned more towards psychological constructs. This review can be used as a reference for choosing a suitable frailty scale depending on the type of fatigue of interest.

Grip Work Measurement with the Jamar Dynamometer: Validation of a Simple Equation for Clinical Use.

OBJECTIVES: Previously, we developed and validated an easy test to measure muscle fatigability during sustained maximal handgrip contraction in older persons using a Martin Vigorimeter device. This study aimed at validating the equation to estimate grip work (GW) during sustained maximal handgrip contraction, by monitoring continuously the grip strength (GS) decay using a Jamar Dynamometer-like (JD) device. DESIGN: Cross sectional, explorative study. SETTING: Data collection took place at The National Research Centre for the Working Environment in Copenhagen, Denmark. PARTICIPANTS: 962 subjects, belonging to a subgroup of the Copenhagen Aging and Midlife Biobank, were enrolled. METHODS: GS was recorded continuously during sustained maximal contraction until it dropped to 50% of its maximum and fatigue resistance (FR, time to fatigue) was noted. GW, area under the force-time curve, was compared to its estimate which was calculated as GWestimated=GSmax*0.75*FR. RESULTS: Excellent correlation was found between GWestimated and GWmeasured (R²=0.98 p<0.001). The equation slightly overestimated GW by 6.04 kg*s (95% CI[-0.08, 12.15]) with a coefficient of variation method error of 6%. CONCLUSION: GW estimation is a valid parameter reflecting muscle work output during a sustained maximal grip effort in healthy middle-aged community-dwelling persons when using a JD. GW estimation is a promising outcome parameter in comprehensive geriatric assessment and its validation for commonly used instruments in geriatric practice will increase its clinical implementation.

Evaluation of appendicular lean mass using bio impedance in persons aged 80+: A new equation based on the BUTTERFLY-study.

BACKGROUND: To date, the accuracy of bio-impedance (BIA) to assess body composition & sarcopenia in persons aged 80 and over remains unclear. OBJECTIVE: We aimed to evaluate the agreement between dual energy X-ray absorptiometry (DXA) and BIA equations to determine lean mass, as well as their suitability to identify sarcopenia. DESIGN: 174 community dwelling well-functioning persons (83 women, 91 men) aged 80 and over were included. Appendicular lean mass (ALM) was predicted using BIA-based equations available in literature, and compared to DXA outcomes. Through cross-validation and stepwise multiple linear regression, a new ALM-formula was generated suitable for this population. RESULTS: Literature-based BIA equations systematically overestimated ALM. The new prediction formula that we propose for the 80+ is: ALM = 0,827+(0,19*Impedance Index)+(2,101*Sex)+(0,079*Weight); R2 = 0,888; SEE = 1,450 kg. Sarcopenia classification based on our new BIA equation for ALM showed better agreement with DXA (k ≥ 0,454) compared to literature-based BIA equations (k < 0,368). CONCLUSIONS: Despite the high correlation between both methods, literature-based BIA equations consistently overestimate ALM compared to DXA in persons aged 80 and over. We proposed a new equation for ALM, reaching higher agreement with DXA and thus improving the accuracy of BIA for this specific age group.

International Clinical Practice Guidelines for Sarcopenia (ICFSR): Screening, Diagnosis and Management.

OBJECTIVES: Sarcopenia, defined as an age-associated loss of skeletal muscle function and muscle mass, occurs in approximately 6 - 22 % of older adults. This paper presents evidence-based clinical practice guidelines for screening, diagnosis and management of sarcopenia from the task force of the International Conference on Sarcopenia and Frailty Research (ICSFR). METHODS: To develop the guidelines, we drew upon the best available evidence from two systematic reviews paired with consensus statements by international working groups on sarcopenia. Eight topics were selected for the recommendations: (i) defining sarcopenia; (ii) screening and diagnosis; (iii) physical activity prescription; (iv) protein supplementation; (v) vitamin D supplementation; (vi) anabolic hormone prescription; (vii) medications under development; and (viii) research. The ICSFR task force evaluated the evidence behind each topic including the quality of evidence, the benefit-harm balance of treatment, patient preferences/values, and cost-effectiveness. Recommendations were graded as either strong or conditional (weak) as per the GRADE (Grading of Recommendations Assessment, Development and Evaluation) approach. Consensus was achieved via one face-to-face workshop and a modified Delphi process. RECOMMENDATIONS: We make a conditional recommendation for the use of an internationally accepted measurement tool for the diagnosis of sarcopenia including the EWGSOP and FNIH definitions, and advocate for rapid screening using gait speed or the SARC-F. To treat sarcopenia, we strongly recommend the prescription of resistance-based physical activity, and conditionally recommend protein supplementation/a protein-rich diet. No recommendation is given for Vitamin D supplementation or for anabolic hormone prescription. There is a lack of robust evidence to assess the strength of other treatment options.

Increasing use of cognitive measures in the operational definition of frailty-A systematic review.

Ageing is associated both with frailty and cognitive decline. The quest for a unifying approach has led to a new concept: cognitive frailty. This systematic review explores the contribution of cognitive assessment in frailty operationalization. PubMed, Web of Knowledge and PsycINFO were searched until December 2016 using the keywords aged; frail elderly; aged, 80 and over; frailty; diagnosis; risk assessment and classification, yielding 2863 hits. Seventy-nine articles were included, describing 94 frailty instruments. Two instruments were not sufficiently specified and excluded. 46% of the identified frailty instruments included cognition. Of these, 85% were published after 2010, with a significant difference for publication date (X2 = 8.45, p < .05), indicating increasing awareness of the contribution of cognitive deficits to functional decline. This review identified 7 methods of cognitive assessment: dementia as co-morbidity; objective cognitive-screening instruments; self-reported; specific signs and symptoms; delirium/clouding of consciousness; non-specific cognitive terms and mixed assessments. Although cognitive assessment has been increasingly integrated in recently published frailty instruments, this has been heterogeneously operationalized. Once the domains most strongly linked to functional decline will have been identified and operationalized, this will be the groundwork for the identification of reversible components, and for the development of preventive interventional strategies.

Does nutrition play a role in the prevention and management of sarcopenia?

There is a growing body of evidence that links nutrition to muscle mass, strength and function in older adults, suggesting that it has an important role to play both in the prevention and management of sarcopenia. This review summarises the discussions of a working group [ESCEO working group meeting 8th September 2016] that met to review current evidence and to consider its implications for preventive and treatment strategies. The review points to the importance of 'healthier' dietary patterns that are adequate in quality in older age, to ensure sufficient intakes of protein, vitamin D, antioxidant nutrients and long-chain polyunsaturated fatty acids. In particular, there is substantial evidence to support the roles of dietary protein and physical activity as key anabolic stimuli for muscle protein synthesis. However, much of the evidence is observational and from high-income countries. Further high-quality trials, particularly from more diverse populations, are needed to enable an understanding of dose and duration effects of individual nutrients on function, to elucidate mechanistic links, and to define optimal profiles and patterns of nutrient intake for older adults.

Force-time characteristics during sustained maximal handgrip effort according to age and clinical condition.

BACKGROUND: Muscle fatigue, a prominent symptom in older patients, can be assessed by sustained maximal handgrip testing. The force decline during sustained maximal contraction is described for young adults, but data for elderly persons are scarce. The aim of this study was to investigate force-time characteristics during a sustained maximal handgrip effort according to age and clinical condition. METHODS AND MATERIALS: Force-time data were continuously recorded during sustained maximal grip effort in 91 elderly patients (aged 83±5years), 100 elderly controls (aged 74±5years) and 100 young controls (aged 23±3years). The force-time curve was divided in 4 parts per 25% strength drop observed. Time (representing fatigue resistance (FR)) was measured during which grip strength (GS) dropped to 75% (FR75), 50% (FR50), 25% (FR25) of its maximum and to exhaustion (FRexhaustion). Grip work ((GW), the area under the force-time curve) was measured for the 4 parts as well as for the first 20 and 30s of the fatigue protocol test. Strength decay (GWdecay), defined as the difference between the area under the curve (% GW) and a theoretical maximal area under the curve (assuming there's no strength drop), was also studied. In the elderly participants, relationships (controlling for age and sex) of GS, FR and GW with circulating IL-6 and TNF-α were analyzed. RESULTS: FRexhaustion was similar for all groups, whereas the duration of each of the 4 parts was significantly different between the 3 groups. FR75 was shortest in old patients (p=0.004), FR75-50 was almost twice as long in old community-dwelling compared to old patients and young controls (p<0.001). This contrast was inverted for FR50-25 which was significantly shorter in old community-dwelling compared to the other groups (p=0.013). FR25-exhaustionwas significantly longer in young controls compared to the groups of older participants (p=0.017). Old patients showed lower GW for the first 2 parts compared to old community-dwelling and young controls. Also, GWdecay values during the first 20 and 30s were significantly higher in old patients compared to old community-dwelling and young controls (both p<0.001). IL-6 was significantly related to lower GSmax, FR75, FR50, FR25, FRexhaustion, GW75, GW50 and GW75-50. CONCLUSION: This is the first study reporting differences in strength decay during a sustained maximal handgrip effort according to age and clinical condition. Old patients showed a particularly rapid decline in GW during the first part of sustained handgrip. GW was also significantly related to circulating IL-6. Future studies should confirm whether a shorter FR test protocol (i.e. until FR75) but using a continuous registration of the strength decay could be more informative in a clinical setting compared to the classical FR test (measuring only FR50).

High Versus Low Load Resistance Training: The Effect of 24 Weeks Detraining on Serum Brain Derived-Neurotrophic Factor (BDNF) in Older Adults.

BACKGROUND: Previously we showed that 12 weeks of mixed-low resistance training (LOW+) significantly increased circulating BDNF in older male individuals. OBJECTIVES: To examine the impact of 24 weeks detraining on circulating BDNF. DESIGN: Randomized intervention study. SETTING: Community-dwelling older adults. PARTICIPANTS AND METHODS: Forty-seven out of 56 participants stopped training (detraining) after 12 weeks of resistance exercise (3x/week) at either HIGH-resistance (5 Males, 5 Females, 2x10-15 repetitions at 80%1RM), LOW-resistance (6 Males, 7 Females, 1x80-100 repetitions at 20%1RM), or mixed-low LOW+-resistance (6 Males, 8 Females, 1x60 repetitions at 20%1RM followed by 1x10-20 repetitions at 40%1RM), of whom 37 (aged 68±5 years) provided sufficient serum samples for BDNF analysis at baseline, 12 week and at 36 weeks (24 weeks detraining). RESULTS: BDNF had initially increased by 31% (from 33.4±10.9 ng/mL to 44.5±13.2 ng/mL, p=0.005) after 12 weeks in the LOW+ exercise group in males and decreased by 26% (from 44.5±13.2 ng/mL to 32.9±10.7 ng/mL) after detraining, though not statistically significant (p=0.082). In females, no significant change in BDNF was found in any of the intervention groups (p>0.05), neither after training, nor detraining. At 36 weeks all of the subgroups showed BDNF levels comparable (all p>0.10) to baseline (before the exercise intervention). CONCLUSIONS: Our results show that a 12-weeks LOW+ resistance exercise increases circulating BDNF in older male subjects but that this reduces back to baseline levels after 24 weeks of detraining. Continuous exercise adherence seems to be needed to sustain the training-induced effects on BDNF in older persons. Additional studies are needed to unravel the underlying mechanisms, as well as to confirm the observed sex difference.

Effects of Physical Exercise on Markers of Cellular Immunosenescence: A Systematic Review.

Aging affects negatively the immune system, defined as immunosenescence, which increases the susceptibility of elderly persons to infection, autoimmune disease, and cancer. There are strong indications that physical exercise in elderly persons may prevent the age-related decline in immune response without significant side effects. Consequently, exercise is being considered as a safe mode of intervention to reduce immunosenescence. The aim of this review was to appraise the existing evidence regarding the impact of exercise on surface markers of cellular immunosenescence in either young and old humans or animals. PubMed and Web of Science were systematically screened, and 28 relevant articles in humans or animals were retrieved. Most of the intervention studies demonstrated that an acute bout of exercise induced increases in senescent, naïve, memory CD4+ and CD8+ T-lymphocytes and significantly elevated apoptotic lymphocytes in peripheral blood. As regards long-term effects, exercise induced increased levels of T-lymphocytes expressing CD28+ in both young and elderly subjects. Few studies found an increase in natural killer cell activity following a period of training. We can conclude that exercise has considerable effects on markers of cellular aspects of the immune system. However, very few studies have been conducted so far to investigate the effects of exercise on markers of cellular immunosenescence in elderly persons. Implications for immunosenescence need further investigation.

Shortcomings in the application of multicolour flow cytometry in lymphocyte subsets enumeration.

The lymphoid system is composed of numerous phenotypically distinct subsets of cells, each of which has a unique role in the effectiveness of an immune response. To distinguish specifically between these subsets, it is mandatory to detect simultaneously different cell surface antigens. This became feasible by the development of multicolour flow cytometric technologies. With these techniques, researchers now have the opportunity to study individual cells in far greater detail than previously possible. However, proper data analysis, interpretation and presentation of results will require a high level of understanding of the intricacies of the technology and the inherent limitations of the acquired data. The present report is intended to contribute to the better understanding of how the flow cytometer operates. This report may help new and inexperienced users to work appropriately with the flow cytometer.

Recovery of muscular performance after surgical stress in elderly patients.

INTRODUCTION: Inflammation is related to muscle wasting in elderly persons. Since surgery is accompanied by an important inflammatory response, the degree of muscle wasting and related symptoms such as weakness and tiredness might exacerbate very rapidly in elderly surgery patients. METHODS: PubMed and Web of Science were systematically screened for articles reporting the influence of surgery-induced inflammation on muscle performance and/or fatigue in elderly patients. Studies reporting surgery-induced inflammation and changes in muscle performance and/or fatigue, but without analyzing their association were excluded. Although 5 relevant articles were identified including older patients (highest ages reported were 71-92 years), none focused exclusively on elderly patients. Only 2 studies assessed muscle performance, and in none muscle mass was evaluated. Overall, we found evidence that in elderly patients higher surgery-induced inflammation was significantly related to worse muscle performance and fatigue in the first postoperative days as well as after more than one month (especially for fatigue) following the intervention. Pre-operative anti-inflammatory treatment using steroids or glucocorticoids can reduce the surgery-induced inflammatory response and improve the recovery of muscle performance and postoperative fatigue in elderly elective abdominal surgery or arthroplasty patients. CONCLUSION: We can conclude that to date, only few studies have investigated the association between surgery-induced inflammation and changes in postoperative muscle performance and fatigue in elderly patients. More research is warranted focusing on both the short -and long-term effects of surgical stress on muscle performance in elderly patients as well as the on risks and benefits of peri-operative anti-inflammatory treatment.

The advanced activities of daily living: a tool allowing the evaluation of subtle functional decline in mild cognitive impairment.

OBJECTIVES: Assessment of advanced activities of daily living (a-ADL) can be of interest in establishing the diagnosis of Alzheimer's disease (AD) in an earlier stage, since these activities demand high cognitive functioning and are more responsive to subtle changes. In this study we tested a new a-ADL tool, developed according to the International Classification of Functioning, Disability and Health (ICF). The a-ADL tool is based on the total number of activities performed (TNA) by a person and takes each subject as his own reference. It distinguishes a total disability index (a-ADL-DI), a cognitive disability index (a-ADL-CDI), and a physical disability index (a-ADL-PDI), with lower score representing more independency. We explored whether these indices allow distinction between cognitively healthy persons, patients with Mild Cognitive Impairment (MCI) and patients with mild AD. METHODS: Participants were on average 80 years old (SD 4.6; 66-90), were community dwelling, and were diagnosed as (1) cognitively healthy subjects (n=26); (2) patients with MCI (n = 17), or (3) mild AD (n = 25), based upon extensive clinical evaluation and a set of global, cognitive, mood and functional assessments. The a-ADL-tool was not part of the clinical evaluation. RESULTS: The a-ADL-CDI was significantly different between the three groups (p<.01). The a-ADL-DI was significantly different between MCI and AD (p<.001). The tool had good psychometrical properties (inter-rater reliability; agreement between patient and proxy; correlations with cognitive tests). Although the sample size was relatively small, ROC curves were computed for the a-ADL-DI and a-ADL-CDI with satisfactory and promising results. CONCLUSION: The a-ADL-CDI and a-ADL-DI might offer a useful contribution to the identification and follow up of patients with mild cognitive disorders in an older population.

Conversion of the Mini-Mental State Examination to the International Classification of Functioning, Disability and Health terminology and scoring system.

BACKGROUND: In older patients, evaluation of the cognitive status is crucial. The Mini-Mental State Examination (MMSE) is widely used for screening of cognition, providing fairly high sensitivity, specificity and reproducibility. Recently, a consensus emerged on the necessity of an international and transparent language, as provided by the WHO's International Classification of Functioning, Disability and Health (ICF). Most assessment tools however are not in accordance with the ICF. OBJECTIVE: To reformulate the MMSE according to the ICF, both for the individual items and for the scoring system. METHOD: MMSE data (scores varying from 3 to 30/30) of (1) 217 cognitively healthy elderly, (2) 60 persons with mild cognitive impairment, (3) 60 patients with mild Alzheimer's disease (AD), and (4) 60 patients with moderate/severe AD were obtained from studies at a university hospital setting. Subjects were aged 65 years or more and recruited either through advertisement (group 1), from the geriatric day hospital (groups 2 and 3), or the geriatric ward (group 4). The allocation to the groups was done after multidisciplinary evaluation. The conversion of the MMSE to ICF-MMSE was done by content comparison and by subsequent translation of the scoring system using automatic algorithms. RESULTS: All MMSE items were converted to the corresponding ICF categories. Three ICF domains were addressed: global and specific mental functions, general tasks and demands, divided over 6 ICF categories (orientation time/place, sustaining attention, memory functions, mental functions of language, undertaking a simple task). Scores on individual items were transformed according to their relative weight on the original MMSE scale, and a total ICF-MMSE score from 0 (no problem) to 100 (complete problem) was generated. Translation was satisfying, as illustrated by a good correlation between MMSE and ICF-MMSE. The diagnostic groups were distributed over the ICF-MMSE scores as expected. For each ICF domain, ICF-MMSE subscores were higher with increasing severity in cognitive decline. There was a higher dispersion, in accordance with the more detailed scoring possibilities of the ICF-MMSE. CONCLUSIONS: It is possible to adapt the MMSE to the ICF concept. This adaptation enhances interdisciplinary communication since it provides more clarity in assessment, with better visibility of the areas covered by the instrument.

Inflammation-related muscle weakness and fatigue in geriatric patients.

Inflammation in older persons is associated with muscle wasting, leading to frailty and functional decline. Most studies have focused on IL-6 and TNF-α. In order to further elucidate the underlying mechanisms of muscle wasting and reduced muscle mass and strength we investigated a large panel of cytokines and chemokines, as well as cytoprotective heat shock proteins (Hsp), and measured lean body mass (LBM) and grip strength (GS), fatigue resistance (FR), and grip work (GW) in 33 geriatric patients (median age 84 years) admitted with acute infection-induced inflammation. Higher expression of Hsp27 without heat challenge (WHC) in circulating monocytes and lymphocytes correlated with better FR (r=0.363, p<0.05 and r=0.602, p<0.001 respectively) suggesting a protective effect, as Hsp27 is abundant in muscle. On the other hand, higher serum levels of the inflammatory chemokines CCL11/Eotaxin and CCL2/MCP-1 were related to lower GS and lower LBM (r=-0.393, p<0.05; r=-0.431, p<0.05) respectively. Our results point to a complex pattern of pro-and anti-inflammatory substances that interact with skeletal muscle performance during acute inflammation.

Direct relationship of body mass index and waist circumference with body tissue distribution in elderly persons.

OBJECTIVES: To explore the relationship of BMI and WC with muscle/adipose tissue mass ratios and with trunk adipose tissue distribution, based on an anatomical 5-compartment model, by dissection of cadavers of elderly persons. DESIGN: Cross-sectional explorative study. SETTING: Brussels Cadaver Analysis Study. PARTICIPANTS: Cadavers of twenty-nine white Caucasian elderly persons (17 females and 12 males, aged 78.1±6.9 years). MEASUREMENTS: Whole body and trunk composition were determined at the anatomical tissue-system level by direct dissection. RESULTS: BMI and WC were significantly and positively related to absolute tissue masses in both sexes. Muscle tissue mass, adipose tissue mass and trunk internal adipose tissue mass correlated better with BMI (r-values between 0.68 and 0.89) than with WC (r-values between 0.49 and 0.71). BMI was significantly and inversely related with various muscle/adipose tissue ratios in both sexes (r-values between -0.54 and -0.68). WC correlated with muscle/adipose tissue ratios in females only (r-values between -0.55 and -0.64). BMI was also significantly related to trunk adipose tissue distribution in elderly females, but not in males. When comparing individual tissue proportions within and between adjacent BMI-classifications or WC categories, body composition varied considerably. CONCLUSION: Our results show that BMI and WC are significantly related with adipose tissue mass and with several ratios of muscle to adipose tissue in elderly subjects. However, cautious clinical interpretation is warranted since important differences in tissue mass proportions were found in subjects with similar BMI and/or WC values.

Grip work estimation during sustained maximal contraction: validity and relationship with dependency and inflammation in elderly persons.

OBJECTIVES: To validate muscle endurance estimation and to examine relationships with dependency and inflammation in elderly persons. DESIGN: Cross sectional validation and explorative study. SETTING: Hospitalized geriatric patients and community-dwelling controls. PARTICIPANTS: 91 elderly patients (aged 83±5 years), 100 elderly controls (aged 74±5 years) and 100 young controls (aged 23±3 years). MEASUREMENTS: Grip strength (GS) was recorded continuously during sustained maximal contraction until exhaustion. Fatigue resistance (FR) was expressed as the time during which GS drops to 50% of its maximum. Grip work (GW) was estimated as GW=GS*0.75*FR, and compared to the measured GW. In the elderly participants, relationships (controlling for age and physical activity) of GS, FR, GW and GW corrected for body weight (GW/BW) with dependency (Katz-scale) and inflammation (circulating IL-6 and TNF-alpha) were analyzed. RESULTS: Excellent correlation between estimated and measured GW was found (r=0.98, p<0.001). The method error coefficient of variance was 10% for all participants; 7% for all elderly and 8% for young controls. Better GS, FR, GW and GW/BW was significantly related with less dependency (all p<0.05 or p<0.01, except for FR in the male) and with lower circulating IL-6 (all p<0.05 or p<0.01, except for GS in both genders). Higher IL-6 was significantly related to worse dependency (p<0.01). No significant relationships with TNF-alpha were found. CONCLUSION: GW estimation is a valid parameter reflecting muscle endurance in elderly persons presenting diverse clinical conditions. GW is significantly related to both dependency and circulating IL-6, and is a promising outcome parameter in comprehensive geriatric assessment.

Quality control of 157 whole body adiposity prediction formulae in age and activity matched men.

AIM AND METHODS: The physiological and clinical importance of body composition is part of public health, nutrition and Sports medicine. The most popular field method for estimating total body adiposity remains anthropometry separately or in formulae. The aim of this study was to verify the suitability of an absolute maximum out of more than 600 existing anthropometry equations estimating % adipose tissue (AT) in a cross validation with dual energy X-ray absorptiometry (DXA), bioelectrical impedance analysis (BIA) and hydrodensitometry (HD) on 74 British male subjects (mean age 34.4±14.1) with different lifestyles corresponding to a maximum of populations the original formula was developed for. RESULTS: Pearson correlation coefficients, paired sample t-test and Bland and Altman plots where used for analyses. From the tested formulae, 19 correlated well (r≥0.70) and showed no significant difference (p>0.05) with BIA, 15 with DXA and only 12 with HD. The results show a better match of the predicted % AT by anthropometric equations with BIA then with DXA or HD. CONCLUSION: All results and conditions considered, this study suggest not to use HD nor anthropometric formulae to assess % AT in men for an individual estimation.

Body mass index as a measure of bone mass.

AIM: BMI is an indicator of body composition (BC) and adiposity in particular. This status is the result of good correlations with indirect (e.g. predictive) two- and three-component models predicting body fat. Aim of the study is to measure the direct relation of BMI with total and segmental BC, e.g. of skin, muscle, bone, viscera and adipose tissue. METHODS: BC constituents of 29 white elderly persons (17 females and 12 males, aged 78.1+/-6.9 years) were determined by direct dissection. Correlations and stepwise linear regression analysis with BMI (dependent variable) and all BC constituents (independent variables) were calculated. RESULTS: All tissues dissected indicated a too high unexplained variance except for bone that accounted for 84% of BMI variance in females and 61% in males (P<0.001). No other constituents improved the prediction. CONCLUSION: The BMI cannot be an appropriate adiposity index. The high proportion of unexplained variance between BMI and direct BC constituents limit its use as a whole body and as a segmental BC index. The BMI could be an index for Bone Mass instead.