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Purpose of the Research: To analyse body composition of patients with Alzheimer's disease (AD) using total body and localized specific bioelectrical impedance vector analysis (specific BIVA)., Method: 127 patients (50 men, 78.2±6.3years; 77 women, 81.4±6.8years) with mild to moderate stages of AD were selected from the Geriatric Division, SS. Trinità Hospital of Cagliari (Italy). A sample of 135 healthy age-matched individuals (74 men, 77.4±5.3years; 61 women, 80.4±5.5years) was chosen as control group. Anthropometric measurements were taken and body mass index (BMI) was calculated. Bioelectrical measurements were taken on the right side of the body for both the whole-body and the arm, using a BIA 101 analyser (Akern). Body composition was assessed by means of specific bioelectrical impedance vector analysis (specific BIVA). The comparison between patients and the control group was performed by two-factor analysis of variance and Hotelling's T 2 test., Results: In comparison with the control group, patients with AD showed similar anthropometric characteristics, including BMI, but lower lean tissue mass and higher percent fat mass, as indicated by the lower phase angles and longer specific vectors. The same body composition peculiarities were detected considering only the right arm., Conclusion: Patients with AD show characteristics - lower lean mass/higher percent fat mass - that can be detected by both total body and localized bioimpedance approaches. This suggests the possibility of a new, quicker and simpler procedure for body composition assessment., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Objective: The aim of this study was to demonstrate the different information provided by body mass index (BMI) in combination with specific bioelectrical impedance vector analysis (specific BIVA) in the measure of relative body fat., Methods: Anthropometric and bioelectrical values and dual-energy x-ray absorpitometry measurements from a sample of 1590 US adults of both sexes were retrieved from the National Health and Nutrition Examination Survey 2003-2004. The sample distribution of the BMI of each sex was divided into deciles. Quartiles were calculated for percent fat mass (FM%) after stratifying by BMI deciles. Body composition and bioelectrical characteristics of groups below the first and above the third quartile were compared using analysis of variance and the Hotelling's T-square test., Results: BMI and specific BIVA showed a different accuracy in detecting body composition variations: BMI showed similar values in groups represented by different FM percentages, whereas the bioelectrical differences were statistically significant. The mean impedance vectors corresponding to cases below the first FM% quartiles were shorter and located on the left side of the ellipses (the region of higher fat-free mass), whereas those above the third FM% quartiles were on the right and toward the upper pole (the region of higher FM%)., Conclusions: Specific BIVA is a technique for the evaluation of body composition which can add relevant information regarding BMI., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Objective: Specific bioelectrical impedance vector analysis (spBIVA) is a recently proposed technique for the analysis of body composition. The aim of this study was to apply spBIVA to a sample of Italian and Spanish young adults and to define the new bioelectrical references for this Western Mediterranean population., Methods: A sample of 440 individuals (220 from Italy, 220 from Spain; 213 men, 227 women) aged 18-30 years was considered. Anthropometric (height, weight, relaxed upper arm, waist, and calf girths) and bioelectrical (resistance, reactance; 50 kHz, 800 μA) measurements were taken. In order to verify the need for new references, specific bioelectrical values were compared to the reference values for U.S. adults and Italian elderly by tolerance ellipses and Student's t test., Results: The mean specific bioelectrical values (resistivity, Rsp, and reactivity, Xcsp, Ohm·cm) were: Rsp (332.7 ± 41.7 Ω·cm), Xcsp (44.4 ± 6.8 Ω·cm), Zsp (335.6 ± 41.9 Ω·cm) and phase (7.6 ± 0.8°) in men; Rsp (388.6 ± 60 Ω·cm), Xcsp (43.7 ± 7.5 Ω·cm), Zsp (391.0 ± 60.3 Ω·cm) and phase (6.4 ± 0.7°) in women. Italo-Spanish bioelectrical vectors were mainly distributed (>90%) in the lower part of the tolerance ellipses for U.S. young adults, due to a shorter impedance (P < 0.001), indicative of a lower percent fat mass. Compared to Italian elders, they were mainly located in the left side (>90%), due to a higher phase (P < 0.001), indicative of higher body cell mass., Conclusions: These population and age-related differences indicate the need for new specific tolerance ellipses that can be used as references for assessing body composition in young adults from Western Mediterranean populations., (© 2015 Wiley Periodicals, Inc.)

This review is directed to define the efficacy of bioelectrical impedance vector analysis (BIVA) for assessing two-compartment body composition. A systematic literature review using MEDLINE database up to 12 February 2014 was performed. The list of papers citing the first description of BIVA, obtained from SCOPUS, and the reference lists of included studies were also searched. Selection criteria included studies comparing the results of BIVA with those of other techniques, and studies analyzing bioelectrical vectors of obese, athletic, cachectic and lean individuals. Thirty articles met the inclusion criteria. The ability of classic BIVA for assessing two-compartment body composition has been mainly evaluated by means of indirect techniques, such as anthropometry and bioelectrical impedance analysis (BIA). Classic BIVA showed a high agreement with body mass index, that can be interpreted in relation to the greater body mass of obese and athletic individuals, whereas the comparison with BIA showed less consistent results, especially in diseased individuals. When a reference method was used, classic BIVA failed to accurately recognize FM% variations, whereas specific BIVA furnished good results. Specific BIVA is a promising alternative to classic BIVA for assessing two-compartment body composition, with potential application in nutritional, sport and geriatric medicine.

Objective: To obtain specific bioelectrical impedance vector reference values for the healthy elderly Italian population, and to study age- and sex-related differences in body composition., Design: The study group consisted of 560 healthy individuals (265 men and 295 women) aged 65 to 100 y, whose anthropometric (height, weight, and calf, arm and waist circumferences) and bioelectrical measurements (resistance [R] and reactance [Xc], at 50 kHz and 800 μA) were recorded. R (Ω) and Xc (Ω) values were standardized for stature (H, m) to obtain the classic bioelectrical values. Specific values (resistivity [Rsp] and reactivity [Xcsp], Ω·cm) were obtained by multiplying R and Xc by a correction factor (A/L) that includes an estimate of the cross-sectional area of the body (A=0.45 arm area+0.10 waist area+0.45 calf area), where L=1.1H., Results: Descriptive statistics were: Rsp (391.8±57.9), Xcsp (42.6±9.9), Zsp (394.2±58.2), phase angle (6.2°±1.2) in men; Rsp (462.0±80.1), Xcsp (47.9±11.2), Zsp (464.6±80.5), phase angle (5.9°±1.0) in women. The Xcsp and phase angle values showed a significant age-related decrease in both sexes, but especially in men, possibly relating to a gradual loss of muscle mass. Women's Rsp and Zsp values tended to drop, attributable to their declining proportion of fat mass. A declining sexual dimorphism was also apparent., Conclusions: Specific tolerance ellipses can be used for reference purposes for the Italian population when assessing body composition in gerontological practice and for epidemiological purposes., (Copyright © 2013 Elsevier Inc. All rights reserved.)

Objectives: Analysis of variations of nutritional status in relation to psycho-functional conditions in elderly patients with mild to moderate Alzheimer's disease (AD) by means of bioelectrical impedance vector analysis (BIVA)., Design: Cross-sectional study., Setting: Alzheimer Center, SS. Trinità Hospital, Cagliari (Italy)., Participants: 83 free-living patients (29 men, 54 women) with mild-moderate Alzheimer's disease, aged 66 to 96 years, and 91 age-matched controls (37 men and 54 women)., Measurements: Nutritional status was evaluated by anthropometry (weight, height, waist and upper arm circumferences, triceps skinfold; body mass index, BMI; arm muscle area, AMA); Mini Nutritional Assessment, MNA®; bioelectrical impedance vector analysis, BIVA. Psycho-functional status was assessed by the Mini Mental State Examination (MMSE), Geriatric Depression Scale (GDS), Activities of Daily Living (ADL), and Instrumental Activities of Daily Living (IADL)., Results: Compared to the control groups, patients with Alzheimer's disease had a worse psycho-functional and nutritional status. BIVA detected lower body cell mass in Alzheimer's patients with respect to controls (men: T²= 23.4; women: T²=27.3; p<0.01), as well as in the female patients with lower levels of IADL and MMSE (respectively, T²= 8.0; T²=7.4; p<0.05). In patients with AD, a worse psycho-functional status was associated with obesity., Conclusion: The psycho-functional decline of patients with AD is related to body composition variations, with a relative increase of fat mass with respect to the muscle component. The BIVA technique distinguished patients from controls and patients with different levels of cognitive decline. Therefore, it is a suitable tool for the screening and monitoring of nutritional status in Alzheimer's disease.

In this study we analyzed body composition in relation to cognitive and functional status, in a cross-sectional sample of patients with Alzheimer's disease (AD). Seventy individuals (27 men, 78.1 ± 6.5 years; 43 women, 80.4 ± 5.6 years) with mild–moderate stages of AD (clinical dementia ratings 1 and 2) were selected from the Alzheimer Center, SS. Trinità Hospital, ASL 8 of Cagliari (Italy). Cognitive and psycho-functional status was evaluated using mini-mental state examination (MMSE), activities of daily living (ADL) scale, and geriatric depression scale (GDS). Mini-nutritional assessment (MNA) was applied. Anthropometric measurements were taken and body mass index (BMI) was calculated. Body composition was assessed by means of specific bioelectrical impedance vector analysis (BIVA), using the references for the elderly. In comparison with the reference group, patients with AD showed similar BMI and MNA, but peculiar bioelectrical characteristics: lower phase angles and longer vectors (p < 0.05). According to specific BIVA, this bioelectrical pattern is indicative of a reduction of lean tissue mass and an increase of percent fat mass (FM%). A more accentuated lean mass reduction (p < 0.05) was observed in women with worse cognitive status and a FM% increase (p < 0.01) in women with worse functional status. In conclusion, patients with AD had lower lean tissue mass and higher percent fat mass than healthy elderly individuals. In women, this pattern was associated with cognitive and functional decline, as indicated by MMSE and ADL values. Specific BIVA showed to be a suitable technique in the elderly, that could enhance BMI and MNA information in the evaluation of nutritional status. [ABSTRACT FROM AUTHOR]