Body composition analysis in older adults with dementia. Anthropometry and bioelectrical impedance analysis: a critical review

Body composition and plasma total-tau, neurofilament light chain, and amyloid-β: A population-based study

A higher body mass at older age has been linked to a lower risk of dementia. This unexpected trend may be explained by age-related lean mass depletion, or methodological issues such as the long preclinical phase of dementia or competing risks. Focusing on preclinical markers of dementia may overcome these issues. Between 2002 and 2005, body composition and plasma total-tau, neurofilament light chain (NfL), amyloid-β40, and amyloid-β42 were measured in 3408 dementia-free participants from the population-based Rotterdam Study. The cross-sectional associations between body composition and plasma markers were determined using linear regression models. Whole body and fat mass, but not lean mass, were positively associated with total-tau, while all these measures were inversely associated with NfL. Apart from an inverse association between lean mass and amyloid-β40, body composition measures were not associated with plasma amyloid-β. Our findings suggest distinct effects of body composition on neurodegeneration.

Assessment of Subnutritional Indices and Associated Risk Factors of Malnutrition Among Older Adults

Malnutrition is a multifactorial problem affecting older adults especially in developing countries like Nigeria. Eighty-five subjects which comprise 55 older adults and 30 controls were recruited. Total protein, Albumin, Calcium, Vitamin-C and Vitamin D were estimated using Biuret's method, Bromo-Cresol Green method, O-Cresolphthalein-Complexone, High performance liquid chromatography, and ELISA methods respectively. Cognitive and nutritional status information were obtained using Mini-Cog test and MNA-short form. Data were analyzed at p < .05. Activities of daily living (ADL) was observed to be associated with nutritional status in older adults. The prevalence of older adults at risk of malnutrition was found to be 58.2%. Blood pressure, albumin and total protein were significantly higher in older adults (p < .05) compared to the younger adults. Total protein was significantly higher in older female subjects (p < .05) compared to older male subjects. It was also significantly higher in non- institutionalized older adults than in those who were institutionalized. Calf circumference was significantly lower (p < .05) in those with poor cognitive status. BMI and calcium were significantly lower in the malnourished older adults. It is concluded that older adults who are dependent, most of which are institutionalized may be more exposed to malnutrition, frailty and cognitive impairment.

Neuropsychiatric Symptoms are Related to Blood-biomarkers in Major Neurocognitive Disorders

BACKGROUND

Neuropsychiatric symptoms (NPS) are highly prevalent among individuals with major neurocognitive disorders (MNCD).

OBJECTIVE

Here, we characterized blood biomarkers (metabolic, inflammatory, neurotrophic profiles and total antioxidant), body composition, physical fitness and quality of life (QoL) in individuals with MNCD according to NPS.

METHODS

The sample comprised 34 older adults (71.4% women; 74.06±6.03 yrs, with MNCD diagnosis) categorized according to 50th percentile [Low (≤12) or High (≥13)] for NPS (Neuropsychiatric Inventory Questionnaire). Sociodemographic, clinical data, body composition, anthropometric, cognitive assessment (ADAS-Cog), physical fitness (Senior Fitness Test), QoL (QoL-Alzheimer's Disease scale) were evaluated, and blood samples were collected for biochemical analysis.

RESULTS

Low compared to high NPS group showed higher levels of IL-6, IGF-1and neurotrophic zscore (composite of IGF-1, VEGF-1, BDNF). Additionally, low compared to high NPS group have higher QoL, aerobic fitness and upper body and lower body strength.

CONCLUSION

The severity of NPS seems to be related to modified neurotrophic and inflammatory outcomes, lower physical fitness, and poor QoL. Strategies to counteract NPS development may preserve the physical and mental health of individuals with MNCD.

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Progress in the study of nutritional status and selenium in dialysis patients

Malnutrition is very common in patients with chronic kidney disease, especially in those on maintenance dialysis. Malnutrition is one of the major factors affecting survival and death of dialysis patients, and reducing their activity tolerance and immunity. There are numerous and interacting risk factors for malnutrition, such as reduced nutritional intake, increased energy expenditure, hormonal disorders, and inflammation. Selenium, in the form of selenoproteins, is involved in many physiological processes in the body and plays an important role in maintaining redox homeostasis. Oxidative stress and infection are very common in dialysis patients, and selenium levels in dialysis patients are significantly lower than those in the healthy population. It has been shown that there is a correlation between selenium levels in hemodialysis patients and their nutrition-related indicators, and that selenium supplementation may improve malnutrition in patients. However, further studies are needed to support this conclusion and there is a lack of basic research to further characterize the potential mechanisms by which selenium may improve malnutrition in dialysis patients. The purpose of this review is to provide a comprehensive overview of factors associated with malnutrition in dialysis patients and to describe the progress of research on nutritional status and selenium levels in dialysis patients.

EFFECTS OF TWENTY-EIGHT MONTHS OF DETRAINING IMPOSED BY THE COVID-19 PANDEMIC ON THE FUNCTIONAL FITNESS OF OLDER WOMEN EXPERIENCED IN CONCURRENT AND FUNCTIONAL TRAINING

Purpose

To assess the impacts of 28 months of detraining imposed by the COVID-19 pandemic on the functional fitness of older women practicing functional or concurrent training.

Material and Methods

A clinical trial with 16 weeks of intervention and 28 months of detraining imposed by the COVID-19 pandemic was conducted. Ninety-five participants were allocated to functional training (FT - 32), concurrent training (CT - 31), or the control group (CG - 32). All the dependent variables were measured pre-training, post-training, and after the detraining period. The functional fitness was assessed by the put on and take off a t-shirt (PTS - upper limbs), timed up and go (TUG - dynamic balance), five times sit-to-stand (FTSST - lower-limb muscle power), gallon-jug shelf-transfer (GJST - global function), and 10 meters walk (W10 m - walking ability) tests.

Results

Sixty-three women remained after the detraining period, twenty-four in the FT (66.0±3.8 years), twenty in the CT (65.0±4.3 years), and nineteen in the CG (69.6±5.9 years). Comparing the detraining vs. the pre-intervention, the FT and CT showed a smaller reduction than CG for the PTS (β_FT=-2.296; β_CT=-1.914), timed up and go (β_FT=-0.705; β_CT=-0.600), five times sit-to-stand (β_FT=-1.970; β_CT=-2.970), gallon-jug shelf-transfer (β_FT=-1.512; β_CT=-1.003), without differences in the 10 meters walk. Also, the concurrent training showed a smaller reduction than the functional training in the FTSST (β = 1.000).

Conclusion

Even after a long detraining period imposed by the COVID-19 pandemic, FT and CT practices were effective strategies for maintaining the functional fitness of older women.

Multicompartment body composition analysis in older adults: a cross-sectional study

BACKGROUND

During aging, changes occur in the proportions of muscle, fat, and bone. Body composition (BC) alterations have a great impact on health, quality of life, and functional capacity. Several equations to predict BC using anthropometric measurements have been developed from a bi-compartmental (2-C) approach that determines only fat mass (FM) and fat-free mass (FFM). However, these models have several limitations, when considering constant density, progressive bone demineralization, and changes in the hydration of the FFM, as typical changes during senescence. Thus, the main purpose of this study was to propose and validate a new multi-compartmental anthropometric model to predict fat, bone, and musculature components in older adults of both sexes.

METHODS

This cross-sectional study included 100 older adults of both sexes. To determine the dependent variables (fat mass [FM], bone mineral content [BMC], and appendicular lean soft tissue [ALST]) whole total and regional dual-energy X-ray absorptiometry (DXA) body scans were performed. Twenty-nine anthropometric measures and sex were appointed as independent variables. Models were developed through multivariate linear regression. Finally, the predicted residual error sum of squares (PRESS) statistic was used to measure the effectiveness of the predicted value for each dependent variable.

RESULTS

An equation was developed to simultaneously predict FM, BMC, and ALST from only four variables: weight, half-arm span (HAS), triceps skinfold (TriSK), and sex. This model showed high coefficients of determination and low estimation errors (FM: R²_adj: 0.83 and SEE: 3.16; BMC: R²_adj: 0.61 and SEE: 0.30; ALST: R²_adj: 0.85 and SEE: 1.65).

CONCLUSION

The equations provide a reliable, practical, and low-cost instrument to monitor changes in body components during the aging process. The internal cross-validation method PRESS presented sufficient reliability in the model as an inexpensive alternative for clinical field use.

Malnutrition Screening and Assessment

Malnutrition is a serious problem with a negative impact on the quality of life and the evolution of patients, contributing to an increase in morbidity, length of hospital stay, mortality, and health spending. Early identification is fundamental to implement the necessary therapeutic actions, involving adequate nutritional support to prevent or reverse malnutrition. This review presents two complementary methods of fighting malnutrition: nutritional screening and nutritional assessment. Nutritional risk screening is conducted using simple, quick-to-perform tools, and is the first line of action in detecting at-risk patients. It should be implemented systematically and periodically on admission to hospital or residential care, as well as on an outpatient basis for patients with chronic conditions. Once patients with a nutritional risk are detected, they should undergo a more detailed nutritional assessment to identify and quantify the type and degree of malnutrition. This should include health history and clinical examination, dietary history, anthropometric measurements, evaluation of the degree of aggression determined by the disease, functional assessment, and, whenever possible, some method of measuring body composition.

Effect of Megestrol Acetate Combined With Oral Nutrition Supplement in Malnourished Lung Cancer Patients: A Single-Center Prospective Cohort Study

Background: The optimal treatment of cancer-related malnutrition remains unknown. A single-center prospective cohort study was performed to compare the efficacy of megestrol acetate (MA) combined with oral nutrition supplement (ONS) and MA alone for the treatment of lung cancer-related malnutrition. Methods: 76 eligible patients were prospectively enrolled in two arms, Arm 1 patients (n = 40, 52.6%) received MA 160 mg/d, and Arm 2 patients (n = 36, 47.4%) received MA 160 mg/d combined with ONS 55.8 g/t.i.d, all orally. All patients received anticancer therapy. Treatment duration was 3 months. The primary endpoints were improvements in body mass index (BMI) and Eastern Cooperative Oncology Group (ECOG) score. Secondary endpoints were assessed by appetite, mid-upper arm circumference (MAC), serum pre-albumin levels, and serum albumin levels. Results: Baseline levels were comparable between Arm 1 and Arm 2 patients. Compared with Arm 1, primary endpoints (BMI, P = 0.018; ECOG, P = 0.022) and secondary endpoints (MAC, P = 0.025; serum pre-albumin, P = 0.043; and serum albumin, P = 0.034) were improved significantly after treatment in Arm 2. While toxicity was negligible and comparable between Arm 1 and Arm 2. Conclusion: MA combined with ONS may be an effective and safe treatment option for lung cancer-related malnutrition patients. Clinical Trial Registration:www.clinicaltrials.gov, identifier ChiCTR2100049007.

Association of Drug Application and Hydration Status in Elderly Patients

Due to multifactorial reasons, such as decreased thirst and decreased total body water, elderly patients are vulnerable to dehydration. Mild cognitive impairment (MCI) or dementia increase the risk of dehydration and, in turn, dehydration decreases cognitive performance. The study aims to identify and assess differences in hydration status, taking into account patients' drug treatment and diseases, using bioelectrical impedance vector analysis (BIVA), thereby revealing unfavorable aspects of prognosis. 447 geriatric patients (241 women, 206 men) including information on medication and bioelectrical impedance analysis (BIA) were investigated, which allowed studying the association between 40 drugs and the hydration status. First, patients were divided into disease groups. Renal disease and diuretic treatment were significantly different in both sexes, whereas cardiovascular patients differed exclusively for females. Next, drug enrichment was examined in either hyperhydrated or dehydrated patients. Simvastatin, candesartan, bisoprolol, amlodipine, olmesartan, furosemide, torasemide, allopurinol, mirtazapine, pantoprazole, cholecalciferol, and resveratrol showed enrichment depending on hydration status. This study demonstrated that patients can be differentiated and stratified by BIVA, taking into account medication and disease associated with hydration status. Although patients diagnosed with MCI and therefore treated with resveratrol, BIVA still showed evaluated dehydration. This is unfavorable in terms of prognosis and requires special attention.

Computed tomographic measurements of the psoas muscle as a predictor of mortality in hip fracture patients: Muscle attenuation helps predict mortality in hip fracture patients

INTRODUCTION

In recent years, sarcopenia has been identified as an important risk factor of patient prognosis. The aim of this study was to determine the association between prognosis of hip fracture and sarcopenia and to evaluate the prognostic performance of psoas muscle volume and attenuation measurements in hip computed tomography (CT).

MATERIAL AND METHODS

This was a retrospective cohort study of patients with hip fracture in our institution from 2014 to 2017. Baseline character data and hip CT scans were obtained. Two readers independently measured muscle size (cross-sectional area) and attenuation of the psoas muscle at the L4 vertebra on CT scans. Logistic regression analysis was used to identify the association between mortality and muscle index (the sum of the left and right muscle sizes divided by patient height) and muscle attenuation after adjusting for demographic variables. In addition, receiver operating characteristic (ROC) curves were obtained.

RESULTS

In the 462 patients included in the study, in-hospital mortality was 4%. Multivariate logistic regression analysis revealed that muscle attenuation was a risk factor for mortality. Among baseline characteristics, age, sex, diastolic blood pressure, and albumin were significant variables for mortality. The area under the ROC curve (AUC) of muscle attenuation for prediction of death was 0.839 (0.803-0.872) with 84.2% sensitivity and 69.5% specificity. Furthermore, when we combined all independent factors according to the results, the AUC was 0.929 (0.902-0.951) with 84.2% sensitivity and 93.6% specificity for prediction of mortality among hip fracture patients.

CONCLUSION

Among many variables, the most significant was muscle attenuation. CT is the most typical modality to determine treatment of hip fracture patients. Measuring muscle size and attenuation is simple using PACS software. Muscle attenuation has significant value for predicting the prognosis of hip patients.

Discordance between Body-Mass Index and Body Adiposity Index in the Classification of Weight Status of Elderly Patients with Stable Coronary Artery Disease

Background and Aims: Body-mass index (BMI) is a popular method implemented to define weight status. However, describing obesity by BMI may result in inaccurate assessment of adiposity. The Body Adiposity Index (BAI) is intended to be a directly validated method of estimating body fat percentage. We set out to compare body weight status assessment by BMI and BAI in a cohort of elderly patients with stable coronary artery disease (CAD). Methods: A total of 169 patients with stable CAD were enrolled in an out-patient cardiology clinic. The National Research Council (US) Committee on Diet and Health classification was used for individuals older than 65 years as underweight BMI < 24 kg/m², normal weight BMI 24–29 kg/m², overweight BMI 29–35 kg/m², and obesity BMI > 35 kg/m². In case of BAI, we used sex- and age-specific classification of weight status. In addition, body fat was estimated by bioelectrical impedance analysis (BImpA). Results: Only 72 out of 169 patients (42.6%) had concordant classification of weight status by both BMI and BAI. The majority of the patients had their weight status either underestimated or overestimated. There were strong positive correlations between BMI and BImpA (FAT%) (R = 0.78 p < 0.001); BAI and BImpA (FAT%) (R = 0.79 p < 0.001); and BMI and BAI (R = 0.67 p < 0.001). BMI tended to overestimate the rate of underweight, normal weight or overweight, meanwhile underestimating the rate of obesity. Third, BMI exhibited an average positive bias of 14.4% compared to the reference method (BImpA), whereas BAI exhibited an average negative bias of −8.3% compared to the reference method (BImpA). Multivariate logistic regression identified independent predictors of discordance in assessing weight status by BMI and BAI: BImpA (FAT%) odds ratio (OR) 1.29, total body water (%) OR 1.61, fat mass index OR 2.62, and Controlling Nutritional Status (CONUT) score OR 1.25. Conclusions: There is substantial rate of misclassification of weight status between BMI and BAI. These findings have significant implications for clinical practice as the boundary between health and disease in malnutrition is crucial to accurately define criteria for intervention. Perhaps BMI cut-offs for classifying weight status in the elderly should be revisited.

The Role of Imaging Biomarkers in the Assessment of Sarcopenia

BACKGROUND

The diagnosis of sarcopenia through clinical assessment has some limitations. The literature advises studies that include objective markers along with clinical assessment in order to improve the sensitivity and specificity of current diagnostic criteria. The decrease of muscle quality precedes the loss of quantity, so we studied the role magnetic resonance imaging biomarkers as indicators of the quantity and quality of muscle in sarcopenia patients.

METHODS

a cross-sectional analysis was performed to analyze what MR-derived imaging parameters correlate better with sarcopenia diagnostic criteria in women of 70 years of age and over (independent walking and community-dwelling women who were sarcopenic in accordance with EWGSOP criteria with muscle mass adjusted to Spanish population were chosen).

RESULTS

The study included 26 women; 81 ± 8 years old. A strong correlation was obtained between cineanthropometric variables (BMI; thigh perimeter and fat mass) and imaging biomarkers (muscle/fat ratio, fatty infiltration, muscle T2*, water diffusion coefficient, and proton density fat fraction) with coefficients around 0.7 (absolute value).

CONCLUSIONS

Knowing the correlation of clinical parameters and imaging-derived muscle quality indicators can help to identify older women at risk of developing sarcopenia at an early stage. This may allow taking preventive actions to decrease disability, morbidity, and mortality in sarcopenia patients.

Numerical estimation of Fricke-Morse impedance model parameters using single-frequency sinusoidal excitation

OBJECTIVE

The Fricke-Morse impedance model is widely used in bioelectrical impedance analysis (BIA), which is usually fitted by multi-frequency electrical impedance data. Here, we propose a novel numerical method for estimating the model parameters using single-frequency sinusoidal excitation.

APPROACH

A single-frequency sinusoidal signal is used as the current excitation, from which the initial transient, the steady-state and the ending transient voltage responses along with the current excitation are recorded. The model parameters can be then estimated with numerical calculations from the acquired signals.

MAIN RESULTS

Simulation and experimental measurements are verified on a 2R1C circuit by using a 50 kHz sinusoidal current excitation. The results show that the maximum relative errors of the estimated model parameters are  <1% in simulation with 2% noise and  <2% in experimental measurement.

SIGNIFICANCE

The proposed method could extend the applications of wideband BIA by using single-frequency excitation, rather than multi-frequency excitation as is done today.

Bioimpedance analysis as an indicator of muscle mass and strength in a group of elderly subjects

OBJECTIVE

To assess the association between whole-body and calf impedance vectors and muscle mass and strength in a group of elderly individuals.

MATERIAL AND METHODS

We carried out a cross-sectional observational study on a sample of 113 elderly people. Anthropometric parameters (weight, height and body circumferences) were determined. Body composition was evaluated using conventional bioimpedance analysis (BIA) and vector bioimpedance analysis (BIVA) (whole-body and calf BIVAs), and muscle strength was determined (manual dynamometry). The results were analyzed using the Student t-test or the Mann-Whitney U, and the correlations using the Pearson or Spearman test. To compare BIVA results among the subgroups established, the Mahalanobis distance (dM) was calculated and the Hotelling T² statistic was used. Statistical significance was set to p < 0.05.

RESULTS

Nearly half the sample was overweight. Based on waist circumference, 66.7% of the males and 94.9% of the females showed risk of metabolic complications; calf circumference indicated no risk of disability or skeletal muscle mass depletion. However, BIA and dynamometry detected risk of sarcopenia in more than half the subjects. Whole-body BIVA results agreed with those of the BIA, given that most impedance vectors in both sexes were to the right of major axis of the tolerance ellipses. This shows cell mass depletion. While the whole-body BIVA distinguished the subjects having loss of muscle mass and strength, the specific BIVA (calf) only did so in individuals with muscle mass loss.

CONCLUSIONS

Whole-body BIVA detects loss of muscle mass and strength, while calf BIVA only distinguishes subjects having muscle mass loss. The localized BIVA might be an alternative to conventional BIA or whole-body BIVA to assess body composition in the elderly.

Effect of sarcopenia on clinical and surgical outcome in elderly patients with proximal femur fractures

PURPOSE

To investigate the relationship between sarcopenia with short-term surgical outcome in elderly patients with proximal femur fractures.

METHODS AND MATERIALS

Following Institutional Review Board approval, a database of patients receiving a pelvis CT scan for acute trauma between January 2000-August 2016 was screened for an isolated proximal femur fracture. Patients were excluded if they were: < 50 years old, had conditions predisposing to sarcopenia (renal failure, congestive heart failure, muscular dystrophies), had undergone no surgical treatment, had other major traumatic injuries, or had a pathologic femur fracture. The paraspinal muscle density (PSD) at the L4 level was measured in Hounsfield units. The skeletal muscle index (SMI) was measured as the total skeletal muscle area at L4 divided by patient height.² PSD and SMI were tested for association with surgical outcome measures: length of hospital stay, perioperative mortality, medical complications, in-hospital blood transfusion volume, and 90-day readmission rate, using multiple variable regression analysis. Pearson correlation of PSD and SMI was performed.

RESULTS

Controlling for age, gender, body mass index (BMI), and fracture type, low PSD and SMI were both independently associated with longer length of hospitalization (p = 0.008 and p = 0.032, respectively). Low PSD was associated with a higher amount of blood transfusion volume during the perioperative period (p = 0.004). Pearson correlation revealed moderate positive correlation between the SMI and PSD (r = 0.579, p < 0.001).

CONCLUSION

In proximal femur fractures, elderly patients with sarcopenia are more likely to have prolonged hospitalization following surgery and require more blood transfusion volume during the perioperative period.

Relationship of aspiration pneumonia to cognitive impairment and oral condition: a cross-sectional study

OBJECTIVES

The objective of this study was to investigate the relationship of the incidence of aspiration pneumonia to cognitive impairment and the oral condition.

MATERIALS AND METHODS

A total of 1174 elderly patients were analyzed in a cross-sectional study. Cognitive function was evaluated by the Clinical Dementia Rating scale and the oral condition was evaluated by inspection and palpation. Swallowing was examined in 196 patients by video-endoscopic evaluation. The Mann-Whitney U test or chi-square test was used for statistical analysis. Conditional logistic regression analysis was performed to compute the odds ratio (OR) and 95% confidence interval (CI).

RESULTS

Loss of posterior occlusion, impaired tongue movements, and impaired cognition were factors significantly related to aspiration pneumonia. The incidence of aspiration pneumonia was higher in patients with both cognitive impairment and loss of posterior occlusion compared with those having either factor alone (OR: 5.16). There was no statistical association between impaired swallowing and the incidence of aspiration pneumonia in elderly patients with normal cognitive function (cognitive impairment, OR: 3.45; normal function, OR: 0.94).

CONCLUSION

Co-existence of cognitive impairment and oral frailty significantly enhances the risk of aspiration pneumonia.

CLINICAL RELEVANCE

Early and simple evaluation of the oral condition and cognitive function can predict the risk of aspiration pneumonia.

CT of Patients With Hip Fracture: Muscle Size and Attenuation Help Predict Mortality

OBJECTIVE

Our objective was to determine the association between muscle cross-sectional area and attenuation, as measured on routine CT scans, and mortality in older patients with hip fracture.

MATERIALS AND METHODS

A retrospective 10-year study of patients with hip fracture was conducted with the following inclusion criteria: age 65 years or older, first-time hip fracture treated with surgery, and CT of the chest, abdomen, or pelvis. This yielded 274 patients (70.4% women; mean [± SD] age, 81.3 ± 8.3 years). On each CT scan, two readers independently measured the size (cross-sectional area, indexed for patient height) and attenuation of the paravertebral muscle at T12 and the psoas muscle at L4. We then determined the association between overall mortality and the muscle size and muscle attenuation, while adjusting for demographic variables (age, sex, ethnicity, and body mass index), American Society of Anesthesiologists (ASA) classification, and Charlson comorbidity index (CCI).

RESULTS

The overall mortality rate increased from 28.3% at 1 year to 79.5% at 5 years. Mortality was associated with decreased thoracic muscle size (odds ratio [OR], 0.66; 95% CI, 0.49-0.87). This association persisted after adjusting for demographic variables (OR, 0.69; 95% CI, 0.50-0.95), the ASA classification (OR, 0.70; CI, 0.51-0.97), and the CCI (OR, 0.72; 95% CI, 0.52-1.00). Similarly, decreased survival was associated with decreased thoracic muscle attenuation after adjusting for all of these combinations of covariates (OR, 0.67-0.72; 95% CI, 0.49-0.99). Decreased lumbar muscle size and attenuation trended with decreased survival but did not reach statistical significance.

CONCLUSION

In older adults with hip fractures, CT findings of decreased thoracic paravertebral muscle size and attenuation are associated with decreased overall survival.

Smart Multi-Frequency Bioelectrical Impedance Spectrometer for BIA and BIVA Applications

Bioelectrical impedance analysis (BIA) is a noninvasive and commonly used method for the assessment of body composition including body water. We designed a small, portable and wireless multi-frequency impedance spectrometer based on the 12 bit impedance network analyzer AD5933 and a precision wide-band constant current source for tetrapolar whole body impedance measurements. The impedance spectrometer communicates via Bluetooth with mobile devices (smart phone or tablet computer) that provide user interface for patient management and data visualization. The export of patient measurement results into a clinical research database facilitates the aggregation of bioelectrical impedance analysis and biolectrical impedance vector analysis (BIVA) data across multiple subjects and/or studies. The performance of the spectrometer was evaluated using a passive tissue equivalent circuit model as well as a comparison of body composition changes assessed with bioelectrical impedance and dual-energy X-ray absorptiometry (DXA) in healthy volunteers. Our results show an absolute error of 1% for resistance and 5% for reactance measurements in the frequency range of 3 kHz to 150 kHz. A linear regression of BIA and DXA fat mass estimations showed a strong correlation (r(2)=0.985) between measures with a maximum absolute error of 6.5%. The simplicity of BIA measurements, a cost effective design and the simple visual representation of impedance data enables patients to compare and determine body composition during the time course of a specific treatment plan in a clinical or home environment.

Different displacement of bioimpedance vector due to Ag/AgCl electrode effect

BACKGROUND/OBJECTIVES

Bioelectrical impedance vector analysis (BIVA) is increasingly used in clinical research to assess soft tissue hydration. It is known that physical characteristics of electrodes, such as low intrinsic impedance, low electrode/skin contact impedance and type of gel, affect the reliability of noninvasive bioimpedance assessments. The aim of this study was to determine the effect of intrinsic impedance of electrode on the bioimpedance vector displacement in RXc graph.

SUBJECTS/METHODS

The intrinsic impedance is measured in nine pregelled disposable Ag/AgCl electrodes usually used for bioimpedance measures. The BIVA method is performed on 35 healthy volunteers using a 50 kHz phase-sensitive bioimpedance analyzer (BIA 101 Anniversary) with the lowest intrinsic impedance electrode and highest. The individual bioimpedance vector is plotted on the bivariate normal interval of reference population. The differences in the mean bioimpedance vectors obtained with each electrode are plotted, with their 95% confidence ellipses, on the dRXc graph. The paired one-sample Hotelling's T²-test is used to compare the differences of the mean bioimpedance vectors.

RESULTS

We found large variability in intrinsic resistance (11-665 Ω) and reactance (0.25-2.5 Ω) values of the electrodes analyzed and significant displacement (P<0.05) of bioimpedance vector positions in healthy adults according to the paired one-sample Hotelling's T²-test.

CONCLUSIONS

A robust study of all physical characteristics of commercial Ag/AgCl electrodes is necessary to reach consensus on pregelled Ag/AgCl electrodes valid for bioimpedance measurement. This information will enable BIVA users to avoid systemic errors when performing BIVA assessments, specifically when these measurements are used for clinical interpretations.

Risk of malnutrition in a sample of nonagenarians: Specific versus classic bioelectrical impedance vector analysis

OBJECTIVES

The aims were to describe the body composition and the risk of malnutrition in a sample of nonagenarians and to identify what bioelectrical impedance vector analysis (BIVA) approach (classic or specific) is more correlated with either the risk of malnutrition or various anthropometric parameters.

METHODS

In the Mugello area (Italy), a representative sample of nonagenarians was enrolled in a survey aimed at investigating various health issues, including those related to nutritional status. The nutritional status was investigated using body mass index (BMI), mid-upper arm circumference (MUAC), calf circumference (CC), Malnutrition Universal Screening Tool (MUST), and BIVA. Two different approaches were used for the BIVA data analysis: the classic method and the specific method.

RESULTS

All measurements were obtained from 321 nonagenarians (65.7% of the enrolled sample; 92 men and 229 women); 74.8% of the subjects were at low risk of malnutrition according to MUST, 62.5% exhibited CC values higher than 31 cm, and 86.8% exhibited MUAC values higher than 22 cm. The bioelectrical parameters varied with nutritional status, independent of the nutritional indicator used; the parameters also varied based on sex and BIVA approach. The bioelectrical parameters obtained by the specific BIVA approach were more strongly correlated with MUST score, MUAC, and CC values compared with the parameters calculated using the classic approach.

CONCLUSIONS

Our study produced findings relevant to particular aspects of population aging. Above all, the specific BIVA was more effective at assessing nutritional status based on both anthropometric parameters and the risk of malnutrition.

Role of nutrition on anemia in elderly

Anemia in elderly population have a great incidence and is related to increased mortality risk. The incidence of nutrition in anemia is about one third of the total. Caloric and protein restriction, iron, vitamin B₁₂, folic deficiency are the causes of nutritional anemia. Protein and energy malnutrition stimulate an increased cytokines production with induction of inflammation, immunodeficiency and anemia. Anorexia and obesity can be associated with anemia due to increased cytokines and hepdicin serum level. Macrophages activity is inhibited and a decrease in red blood cells (RBC), hemoglobin (Hb) concentration due to ineffective erythropoiesis is observed. An adequate energy and protein diet is necessary to reduce inflammation and increase iron absorption. A minimum of 1700 kcal/day and 1.7 gr/kg/day of protein intake are necessary to maintain anabolism in chronic patients to prevent and treat anemia. Iron supplementation by intravenous injection is safe and effective to correct severe iron deficiency. The supplementation of vitamins and oligomineral are useful to reduce oxidative stress and improve RBC longevity. Anemia in elderly could be prevented by an adequate nutrition, a simple and not expensive intervention, and associated to physical exercise reduce the incidence of mortality rate.

Body mass index and waist circumference are not good surrogate indicators of adiposity in psychogeriatric patients

OBJECTIVE

to assess the utility of body mass index (BMI) and waist circumference (WC) as surrogate indicators of adiposity with respect to the total body fat estimated with bioimpedance analysis in psychogeriatric patients.

METHODS

Anthropometric and hand-to-foot bioimpedance measurements were performed according to standard procedures in a sample of 128 psychogeriatric patients (87 males, 41 females). WC cutoffs proposed by the International Diabetes Federation were used to define abdominal obesity. Z-scores of fat and fat-free mass indices (Z-FMI and Z-FFMI) were calculated.

RESULTS

Males with WC values below the cutoff were normal weight, and showed normal levels of FM and low FFM (Z-FFMI below 1.5 SD). Males with WC values above the cutoff were overweight, showed high levels of FM (Z-FMI: 1.34 SD) and a slight depletion of FFM (Z-FFMI: -0.59 SD). In females with WC values below the cutoff, BMI was close to 20 kg/m(2) and both FM and FFM were depleted (Z-FMI: -0.7 SD; Z-FFMI: -1.76 SD). In females with WC above the cutoff, the average BMI was 25.6 kg/m(2) , Z-FMI was 0.48 SD, and Z-FFMI was -0.56 SD.

CONCLUSIONS

Our results indicate that it is necessary to establish age and sex-specific BMI and WC cutoffs, and also highlight the importance of focusing on body composition analysis to ensure an accurate nutritional diagnosis in older-adults and in psychogeriatric patients.

Anthropometric reference data for elderly Swedes and its disease-related pattern

Background/Objectives:

Anthropometric measurement is a noninvasive and cost-efficient method for nutritional assessment. The study aims to present age- and gender-specific anthropometric reference data for Swedish elderly in relation to common medical conditions, and also formulate prediction equations for such anthropometric measurements.

Subjects/Methods:

A cross-sectional study among random heterogeneous sample of 3360 subjects, aged 60–99 years, from a population study ‘Good Aging in Scania. Means (±s.d.) and percentiles for height, weight, waist-, hip-, arm-, calf circumferences, triceps- (TST) and subscapular skinfold thickness (SST), body mass index (BMI), waist-hip ratio (WHR) and arm muscle circumference (AMC) were presented. The values were estimated based on the prevalence of myocardial infarction (MI), cardiac failure (CHF), stroke, cognitive impairment, dementia and dependence in daily living activities (ADL). Linear regression analysis was used to formulate the prediction equations.

Results:

Mean BMI was 27.5±5.8 kg/m² (men) and 27.2±8.1 kg/m² (women). WHR was higher among men (Men: 0.98±0.3, women: 0.87±0.2), except at age 85+ (women: 0.91±0.6). TST was 6.7±0.4 mm higher among women. Men with MI had BMI: 28.6±4.8 kg/m² and SST: 21±9.2 mm, whereas subjects with dementia had lower weight (by 9.5±2.9 kg) compared with the non-demented. ADL-dependent women had BMI= 29.0±3.9 kg/m², TST=19.2±1.3 mm.

Conclusion:

New normative data on gender- and age-specific anthropometrics on the general elderly population are presented. Cardiovascular diseases are associated with subcutaneous and central adiposity opposed to fat loss with dementia. ADL dependence indicates inadequate physical activity. The prediction models could be used as possible indicators monitoring physical activity and adiposity among the general elderly population hence potential health indicators in health promotion.