Water homeostasis, frailty and cognitive function in the nursing home

Normal values for body composition in adults are better represented by continuous reference ranges dependent on age and BMI

BACKGROUND & AIMS

Reference values for body composition parameters like skeletal muscle mass index (SMI) depend on age and BMI. To ensure reference intervals reflect these changes, they have traditionally been separated into groups of young adults based on sex and BMI. However, this static stratification oversimplifies the dynamic and gradual changes of body composition with increasing age and BMI. The aim was therefore to provide continuous reference ranges for body composition parameters.

METHODS

Cross-sectional data of 1958 healthy men and women with an age between 18 and 97 years and a BMI between 17.1 und 45.6 kg/m² were obtained between 2011 and 2019. Multiple regression analyses stratified by sex with age, age² and BMI as independent variables were conducted to predict fat mass index (FMI), visceral adipose tissue (VAT), SMI, appendicular lean soft tissue index (ALSTI) and the ratio between extracellular to total body water (ECW/TBW).

RESULTS

The regression models explained between 61 (VAT in women and ALSTI in men) and 93% of the variance in the respective body composition parameters (FMI in women). Age had only a minor impact (2-16%) whereas BMI substantially increased the explained variance of reference models for FMI, VAT and ALSTI (total explained variance 61-93%). In SMI, age is a major determinant of the explained variance (36% in men and 38% in women) with BMI equally contributing to the explained variance (total explained variance 72% in men and 75% in women). For ECW/TBW-ratio, age nearly completely explained the variance (79% in men and 74% in women) whereas BMI added only 2-3% to the explained variance.

CONCLUSIONS

In conclusion, the derived continuous reference ranges are expected to improve body composition evaluation especially in very overweight and very old persons. Future studies applying these reference equations need to validate these assumptions. STUDY REGISTRATION, CLINICALTRIALS.GOV: NCT01368640, NCT01481285, NCT03779932, NCT04028648.

Association between Disability and Edema Index Values in Rural Older Adult Osteosarcopenia Patients

PURPOSE

This study analyzed the relationship between degree of disability and edema index [extracellular water/total body water (ECW/TBW) ratio] values in a rural population of older adult patients with osteopenia, sarcopenia, or osteosarcopenia (OS).

MATERIALS AND METHODS

This study used data from the Namgaram-2 cohort. The degree of disability was measured using the World Health Organization Disability Assessment Schedule (WHODAS) 12, and ECW/TBW ratio was calculated using bioelectrical impedance analysis. Based on ECW/TBW ratio, the participants were stratified into normal (<0.391) and abnormal (≥0.391) groups, and the mean WHODAS 12 scores were compared between the two groups. Multiple regression analysis corrected for demographic factors, smoking history, hypertension, diabetes, and serological test results was also conducted.

RESULTS

Significant differences in mean WHODAS 12 scores were observed in the healthy group (5.8±7.4 vs. 9.2±9.7, p=0.008), the osteopenia only group (7.4±8.7 vs. 12.9±12.0, p<0.001), and the OS group (16.0±13.2 vs. 23.1±17.1, p=0.004). However, no significant difference in mean WHODAS 12 score was observed in the sarcopenia only group (14.9±13.4 vs. 20.7±14.8, p= 0.051). There were significant differences in ECW/TBW ratio values between the abnormal and normal groups in the osteopenia only group (B=4.646 and p=0.001), the sarcopenia only group (B=5.097 and p=0.016), and the OS group (B=5.653 and p=0.043).

CONCLUSION

This study found that the degree of disability is related to the edema index in older patients with osteopenia, sarcopenia, or OS. Since the edema index indicates the nutritional status of an individual, proper nutrition and fluid intake are important to reduce disability.

Extracellular to Intracellular Body Water and Cognitive Function among Healthy Older and Younger Adults

Compromised cognitive function is associated with increased mortality and increased healthcare costs. Physical characteristics including height, weight, body mass index, sex, and fat mass are often associated with cognitive function. Extracellular to intracellular body water ratio offers an additional anthropometric measurement that has received recent attention because of its association with systemic inflammation, hypertension, and blood−brain barrier permeability. The purposes of this study were to determine whether extracellular to intracellular body water ratios are different between younger and older people and whether they are associated with cognitive function, including executive function and attention, working memory, and information processing speed. A total of 118 healthy people (39 older; 79 younger) participated in this study. We discovered that extracellular to intracellular body water ratio increased with age, was predictive of an older person’s ability to inhibit information and stay attentive to a desired task (Flanker test; R2 = 0.24; p < 0.001), and had strong sensitivity (83%) and specificity (91%) to detect a lower executive function score. These findings support that extracellular to intracellular body water ratio offers predictive capabilities of cognitive function, even in a healthy group of elderly people.

The relationship between extracellular water-to-body water ratio and sarcopenia according to the newly revised Asian Working Group for Sarcopenia: 2019 Consensus Update

OBJECTIVE

The purpose of this study was to evaluate the association between sarcopenia and extracellular water-to-total body water ratio (ECW/TBW), one of the results of bioimpedance that can be easily measured in communities, following the recent revision of the Asian Working Group for Sarcopenia.

METHODS

This study data were extracted from the baseline data of Namgaram-2. Among the surveyed subjects, 885 persons aged 60 years or older were selected as study subjects. All surveys were conducted on a one-on-one interview basis; blood tests, physical function evaluations (hand grip strength, short physical performance battery; SPPB), and dual-energy X-ray absorptiometry (DEXA) and bioimpedance were also conducted. The Asian Working Group's revised definition of sarcopenia was applied. ECW/TBW was one of the results of bioimpedance this study.

RESULTS

A high ECW/TBW was 1.63 times higher in the low grip strength group than in the robust group (P = 0.017) and was 2.13 times higher in the low SPPB group compared to the robust group (P < 0.001). ECW/TBW higher than 0.391 was 2.17 times more likely to occur in sarcopenic patients compared to the robust group (P < 0.001). In addition, ECW/TBW lower than 0.391 was 3.65 times more likely to occur in severely sarcopenic patients compared to the robust group (P = 0.002).

CONCLUSION

The ECW/TBW may be one of the valid research tools to evaluate the strength and physical performance of the elderly. In addition, it is expected to be one of the effective indicators for tracking physical function under newly revised sarcopenia criteria.

Serum Zinc Level Is Associated with Frailty in Chronic Liver Diseases

We sought to examine the serum zinc (Zn) level and frailty in patients with chronic liver diseases (CLDs, n = 285, 107 liver cirrhosis cases, median age = 66 years). Frailty was defined as a clinical syndrome in which three or more of the following criteria were met (frailty score 3, 4, or 5): unintentional body weight loss, self-reported exhaustion, muscle weakness (grip strength: <26 kg in men and <18 kg in women), slow walking speed (<1.0 m/s), and low physical activity. Robust (frailty score 0), prefrail (frailty score 1 or 2), and frailty were found in 90 (31.6%), 157 (55.1%), and 38 (13.3%), respectively. The median serum Zn levels in patients with frailty, prefrailty, and robust were 59.7 μg/dL, 72.8 μg/dL, and 76.9 μg/dL, respectively (p-values: frailty vs. prefrail, p < 0.0001; prefrail vs. robust, p = 0.0063; frailty vs. robust, p < 0.0001; overall p < 0.0001). For all cases, variables with absolute values of correlation coefficient with frailty score (0–5) ≥ 0.3 were age (r_s = 0.3570, p < 0.0001), serum albumin (r_s = −0.3212, p < 0.0001), extracellular water to total body water ratio using bioimpedance analysis (r_s = 0.4386, p < 0.0001), and serum Zn level (r_s = −0.3406, p < 0.0001). In conclusion, decreased serum Zn level in patients with CLDs can be closely associated with the presence of frailty.

Relation of Disease with Standardized Phase Angle among Older Patients

BACKGROUND

A low phase angle (PA) has been associated with negative outcome in specific diseases. However, many patients suffer from several co-morbidities. This study aims at identifying the impact of the type and the severity of diseases on PA in a retrospective cohort study of older people.

METHODS

We included all people ≥65 years who underwent a PA measurement (Nutriguard®) between 1990 and 2011 at the Geneva University Hospitals. PA was standardized for gender, age and body mass index according to German reference values. Co-morbidities were reported in form of the Cumulative Illness Rating Scale which considers 14 different organs/systems (disease categories), each rated from 0 (healthy) to 4 (severe illness) (severity grades). The association between the diseases categories and standardized PA was evaluated by a multivariate linear regression. For each significant disease category, we performed univariate regression models. The adjusted R2 was used to identify the best predictors of standardized PA. We considered that the severity grade affected standardized PA if there was a progressive decrease in the regression coefficients.

RESULTS

We included 1181 people (37% women). The multivariate regression model showed that the disease categories explain 17% of the variance of standardized PA. Many disease categories affect standardized PA and the ones best associated with standardized PA were the hematopoietic and vascular (R2 7.4%), the musculo-skeletal (R2 5.5%) and the respiratory (R2 4.0%) diseases. The regression coefficients in the univariate linear regression model decreased progressively with higher severity grades in respiratory (-0.15, -0.27, -0.55, -0.67) and musculo-skeletal diseases (-0.09, -0.46, -0.85, -0.86).

CONCLUSIONS

Many different diseases affect standardized PA. The higher the severity grade in musculo-skeletal and respiratory diseases, the lower is the standardized PA.

Body Composition Tools for Assessment of Adult Malnutrition at the Bedside: A Tutorial on Research Considerations and Clinical Applications

Because of the key role played by the body's lean tissue reserves (of which skeletal muscle is a major component) in the response to injury and illness, its maintenance is of central importance to nutrition status. With the recent development of the Academy of Nutrition and Dietetics/American Society for Parenteral and Enteral Nutrition diagnostic framework for malnutrition, the loss of muscle mass has been recognized as one of the defining criteria. Objective methods to evaluate muscle loss in individuals with acute and chronic illness are needed. Bioimpedance and ultrasound techniques are currently the best options for the clinical setting; however, additional research is needed to investigate how best to optimize measurements and minimize error and to establish if these techniques (and which specific approaches) can uniquely contribute to the assessment of malnutrition, beyond more subjective evaluation methods. In this tutorial, key concepts and statistical methods used in the validation of bedside methods to assess lean tissue compartments are discussed. Body composition assessment methods that are most widely available for practice and research in the clinical setting are presented, and clinical cases are used to illustrate how the clinician might use bioimpedance and/or ultrasound as a tool to assess nutrition status at the bedside. Future research needs regarding malnutrition assessment are identified.

Frailty and the risk of cognitive impairment

Aging occurs as a series of small steps, first causing cellular damage and then affecting tissues and organs. This is also true in the brain. Frailty, a state of increased risk due to accelerated deficit accumulation, is robustly a risk factor for cognitive impairment. Community-based autopsy studies show that frail individuals have brains that show multiple deficits without necessarily demonstrating cognitive impairment. These facts cast a new light on the growing number of risk factors for cognitive impairment, suggesting that, on a population basis, most health deficits can be associated with late-life cognitive impairment. The systems mechanism by which things that are bad for the body are likely to be bad for the brain can be understood like this: the burden of health deficits anywhere indicates impaired ability to withstand or repair endogenous and environmental damage. This in turn makes additional damage more likely. If true, this suggests that a life course approach to preventing cognitive impairment is desirable. Furthermore, conducting studies in highly selected, younger, healthier individuals to provide ‘proof of concept’ information is now common. This strategy might exclude the very circumstances that are required for disease expression in the people in whom dementia chiefly occurs (that is, older adults who are often in poor health).

Clinical symptoms, signs and tests for identification of impending and current water-loss dehydration in older people

BACKGROUND

There is evidence that water-loss dehydration is common in older people and associated with many causes of morbidity and mortality. However, it is unclear what clinical symptoms, signs and tests may be used to identify early dehydration in older people, so that support can be mobilised to improve hydration before health and well-being are compromised.

OBJECTIVES

To determine the diagnostic accuracy of state (one time), minimally invasive clinical symptoms, signs and tests to be used as screening tests for detecting water-loss dehydration in older people by systematically reviewing studies that have measured a reference standard and at least one index test in people aged 65 years and over. Water-loss dehydration was defined primarily as including everyone with either impending or current water-loss dehydration (including all those with serum osmolality ≥ 295 mOsm/kg as being dehydrated).

SEARCH METHODS

Structured search strategies were developed for MEDLINE (OvidSP), EMBASE (OvidSP), CINAHL, LILACS, DARE and HTA databases (The Cochrane Library), and the International Clinical Trials Registry Platform (ICTRP). Reference lists of included studies and identified relevant reviews were checked. Authors of included studies were contacted for details of further studies.

SELECTION CRITERIA

Titles and abstracts were scanned and all potentially relevant studies obtained in full text. Inclusion of full text studies was assessed independently in duplicate, and disagreements resolved by a third author. We wrote to authors of all studies that appeared to have collected data on at least one reference standard and at least one index test, and in at least 10 people aged ≥ 65 years, even where no comparative analysis has been published, requesting original dataset so we could create 2 x 2 tables.

DATA COLLECTION AND ANALYSIS

Diagnostic accuracy of each test was assessed against the best available reference standard for water-loss dehydration (serum or plasma osmolality cut-off ≥ 295 mOsm/kg, serum osmolarity or weight change) within each study. For each index test study data were presented in forest plots of sensitivity and specificity. The primary target condition was water-loss dehydration (including either impending or current water-loss dehydration). Secondary target conditions were intended as current (> 300 mOsm/kg) and impending (295 to 300 mOsm/kg) water-loss dehydration, but restricted to current dehydration in the final review.We conducted bivariate random-effects meta-analyses (Stata/IC, StataCorp) for index tests where there were at least four studies and study datasets could be pooled to construct sensitivity and specificity summary estimates. We assigned the same approach for index tests with continuous outcome data for each of three pre-specified cut-off points investigated.Pre-set minimum sensitivity of a useful test was 60%, minimum specificity 75%. As pre-specifying three cut-offs for each continuous test may have led to missing a cut-off with useful sensitivity and specificity, we conducted post-hoc exploratory analyses to create receiver operating characteristic (ROC) curves where there appeared some possibility of a useful cut-off missed by the original three. These analyses enabled assessment of which tests may be worth assessing in further research. A further exploratory analysis assessed the value of combining the best two index tests where each had some individual predictive ability.

MAIN RESULTS

There were few published studies of the diagnostic accuracy of state (one time), minimally invasive clinical symptoms, signs or tests to be used as screening tests for detecting water-loss dehydration in older people. Therefore, to complete this review we sought, analysed and included raw datasets that included a reference standard and an index test in people aged ≥ 65 years.We included three studies with published diagnostic accuracy data and a further 21 studies provided datasets that we analysed. We assessed 67 tests (at three cut-offs for each continuous outcome) for diagnostic accuracy of water-loss dehydration (primary target condition) and of current dehydration (secondary target condition).Only three tests showed any ability to diagnose water-loss dehydration (including both impending and current water-loss dehydration) as stand-alone tests: expressing fatigue (sensitivity 0.71 (95% CI 0.29 to 0.96), specificity 0.75 (95% CI 0.63 to 0.85), in one study with 71 participants, but two additional studies had lower sensitivity); missing drinks between meals (sensitivity 1.00 (95% CI 0.59 to 1.00), specificity 0.77 (95% CI 0.64 to 0.86), in one study with 71 participants) and BIA resistance at 50 kHz (sensitivities 1.00 (95% CI 0.48 to 1.00) and 0.71 (95% CI 0.44 to 0.90) and specificities of 1.00 (95% CI 0.69 to 1.00) and 0.80 (95% CI 0.28 to 0.99) in 15 and 22 people respectively for two studies, but with sensitivities of 0.54 (95% CI 0.25 to 0.81) and 0.69 (95% CI 0.56 to 0.79) and specificities of 0.50 (95% CI 0.16 to 0.84) and 0.19 (95% CI 0.17 to 0.21) in 21 and 1947 people respectively in two other studies). In post-hoc ROC plots drinks intake, urine osmolality and axillial moisture also showed limited diagnostic accuracy. No test was consistently useful in more than one study.Combining two tests so that an individual both missed some drinks between meals and expressed fatigue was sensitive at 0.71 (95% CI 0.29 to 0.96) and specific at 0.92 (95% CI 0.83 to 0.97).There was sufficient evidence to suggest that several stand-alone tests often used to assess dehydration in older people (including fluid intake, urine specific gravity, urine colour, urine volume, heart rate, dry mouth, feeling thirsty and BIA assessment of intracellular water or extracellular water) are not useful, and should not be relied on individually as ways of assessing presence or absence of dehydration in older people.No tests were found consistently useful in diagnosing current water-loss dehydration.

AUTHORS' CONCLUSIONS

There is limited evidence of the diagnostic utility of any individual clinical symptom, sign or test or combination of tests to indicate water-loss dehydration in older people. Individual tests should not be used in this population to indicate dehydration; they miss a high proportion of people with dehydration, and wrongly label those who are adequately hydrated.Promising tests identified by this review need to be further assessed, as do new methods in development. Combining several tests may improve diagnostic accuracy.

Sarcopenia and the analysis of body composition

Reduction of lean mass is a primary body composition change associated with aging. Because many factors contribute to lean mass reduction, the problem has been given various names depending on the proposed cause, such as "age-related sarcopenia," "dynapenia," "myopenia," "sarcopenic obesity," or simply "sarcopenia." There is currently no consensus on how to best diagnose the reduction of lean mass and its consequences on health. We propose that simple body composition methods can be used to indirectly evaluate sarcopenia, provided that those techniques are validated against the "quality of lean" criterion that associates muscle mass and metabolic function with the components of fat-free mass. Promising field methods include the use of stable isotopes for the evaluation of water compartments and new approaches to bioelectrical impedance analysis, which is also associated with the monitoring of water homeostasis.

How to design nutritional intervention trials to slow cognitive decline in apparently healthy populations and apply for efficacy claims: a statement from the International Academy on Nutrition and Aging Task Force

Interventions are crucial as they offer simple and inexpensive public health solutions that will be useful over the long term use. A Task Force on designing trials of nutritional interventions to slow cognitive decline in older adults was held in Toulouse in September 2012. The aim of the Task Force was to bring together leading experts from academia, the food industry and regulatory agencies to determine the best trial designs that would enable us to reach our goal of maintaining or improving cognitive function in apparently healthy aging people. An associated challenge for this Task Force was to determine the type of trials required by the Public Food Agencies for assessing the impact of nutritional compounds in comparison to well established requirements for drug trials. Although the required quality of the study design, rationale and statistical analysis remains the same, the studies designed to show reduction of cognitive decline require a long duration and the objectives of this task force was to determine best design for these trials. Two specific needs were identified to support trials of nutritional interventions: 1- Risk- reduction strategies are needed to tackle the growing burden of cognitive decline that may lead to dementia, 2- Innovative study designs are needed to improve the quality of these studies.

What makes a BIA equation unique? Validity of eight-electrode multifrequency BIA to estimate body composition in a healthy adult population

BACKGROUND/OBJECTIVES

The validity of bioelectrical impedance analysis (BIA) for body composition analysis is limited by assumptions relating to body shape. Improvement in BIA technology could overcome these limitations and reduce the population specificity of the BIA algorithm.

SUBJECTS/METHODS

BIA equations for the prediction of fat-free mass (FFM), total body water (TBW) and extracellular water (ECW) were generated from data obtained on 124 Caucasians (body mass index 18.5-35 kg/m(2)) using a four-compartment model and dilution techniques as references. The algorithms were validated in an independent multiethnic population (n=130). The validity of BIA results was compared (i) between ethnic groups and (ii) with results from the four-compartment model and two-compartment methods (air-displacement plethysmography, dual-energy X-ray absorptiometry and deuterium dilution).

RESULTS

Indices were developed from segmental R and Xc values to represent the relative contribution of trunk and limbs to total body conductivity. The coefficient of determination for all prediction equations was high (R(2): 0.94 for ECW, 0.98 for FFM and 0.98 for TBW) and root mean square error was low (1.9 kg for FFM, 0.8 l for ECW and 1.3 kg for TBW). The bias between BIA results and different reference methods was not statistically different between Afro-American, Hispanic, Asian or Caucasian populations and showed a similar difference (-0.2-0.2 kg FFM) when compared with the bias between different two-compartment reference methods (-0.2-0.3 kg FFM).

CONCLUSIONS

An eight-electrode, segmental multifrequency BIA is a valid tool to estimate body composition in healthy euvolemic adults compared with the validity and precision of other two-compartment reference methods. Population specificity is of minor importance when compared with discrepancies between different reference methods.

Accuracy of specific BIVA for the assessment of body composition in the United States population

Background

Bioelectrical impedance vector analysis (BIVA) is a technique for the assessment of hydration and nutritional status, used in the clinical practice. Specific BIVA is an analytical variant, recently proposed for the Italian elderly population, that adjusts bioelectrical values for body geometry.

Objective

Evaluating the accuracy of specific BIVA in the adult U.S. population, compared to the ‘classic’ BIVA procedure, using DXA as the reference technique, in order to obtain an interpretative model of body composition.

Design

A cross-sectional sample of 1590 adult individuals (836 men and 754 women, 21–49 years old) derived from the NHANES 2003–2004 was considered. Classic and specific BIVA were applied. The sensitivity and specificity in recognizing individuals below the 5^th and above the 95^th percentiles of percent fat (FM_DXA%) and extracellular/intracellular water (ECW/ICW) ratio were evaluated by receiver operating characteristic (ROC) curves. Classic and specific BIVA results were compared by a probit multiple-regression.

Results

Specific BIVA was significantly more accurate than classic BIVA in evaluating FM_DXA% (ROC areas: 0.84–0.92 and 0.49–0.61 respectively; p = 0.002). The evaluation of ECW/ICW was accurate (ROC areas between 0.83 and 0.96) and similarly performed by the two procedures (p = 0.829). The accuracy of specific BIVA was similar in the two sexes (p = 0.144) and in FM_DXA% and ECW/ICW (p = 0.869).

Conclusions

Specific BIVA showed to be an accurate technique. The tolerance ellipses of specific BIVA can be used for evaluating FM% and ECW/ICW in the U.S. adult population.

Efficacy of specific bioelectrical impedance vector analysis (BIVA) for assessing body composition in the elderly

OBJECTIVES

This study aimed to ascertain the efficacy of bioelectrical impedance vector analysis (BIVA) in assessing body composition in the elderly by comparing findings with the results of dual-energy X-ray absorptiometry (DXA), and to test an analytical variant of the method (specific BIVA).

DESIGN

Cross-sectional study.

PARTICIPANTS

The sample comprised 207 free-living elderly individuals (75 men and 132 women) aged 65 to 93 years.

MEASUREMENTS

Anthropometric and bioelectrical measurements were taken according to standard criteria. BIVA was applied using the 'classic' procedure and correcting bioelectrical values for body geometry to obtain an estimate of the whole-body impedivity. DXA was used as a reference body composition assessment method. BIVA (classic and specific values) and DXA findings were compared using Student's t and Hotelling's T2 tests, and Pearson's correlation coefficient.

RESULTS

In both sexes, BIVA distinguished between individuals with different amounts of fat and fat-free mass (lean mass including bone mineral content), according to DXA, but not between those with different proportions of fat mass (FM%). Specific bioelectrical values detected changes in body composition.

CONCLUSION

BIVA should be used with caution for evaluating body composition in the elderly. Specific bioelectrical values proved effective, showing promise as a methodological variant of BIVA, suitable for identifying age-related changes in body fatness.