Association between phase angle of bioelectrical impedance analysis and nutritional parameters in older adults

INTRODUCTION: Phase angle (PhA) is a Bioelectrical impedance analysis (BIA) parameter representing an indicator of cellular health and has been suggested as a biomarker of nutritional status. OBJECTIVE: To evaluate the association between PhA and nutritional parameters in older adults. METHODS: A cross-sectional study was conducted with community-dwelling older adults. Body mass index (BMI), arm muscle circumference (AMC), calf circumference (CC), body fat percentage (BF%), appendicular skeletal muscle mass (ASMM), serum albumin, mini-nutritional assessment (MNA), and PhA were assessed. Kolmogorov­Smirnov test, Spearman's correlation coefficient, chi-square test, and Poisson regression models were performed. RESULTS: 144 participants were included in the study, and most of them were female, aged ≥80 years, and underweight. Most older adults with lower PhA were women, aged range 80­89 years, and with reduced ASMM (p<0.05). PhA presented a significant correlation with age (r=­0.417; p<0.001), ASMM (r=0.427; p<0.001), AMC (r=0.195; p=0.019) and BF% (r=­0.223; p=0.007). Older adults with lower PhA present reduced ASMM (PR: 1.25; 95%CI: 1.04­1.50), and hypoalbuminemia (PR: 1.50; 95%CI: 1.11­2.03). CONCLUSION: PhA is related to commonly nutritional indicators used in clinical practice and could be an important biomarker of muscle mass reserves in community-living older adults of both sexes.

The use of bioelectrical impedance vector analysis for a nutritional evaluation of older adults in the community.

INTRODUCTION: The body composition of an older adult person is characterized by an increase in body fat, as well as by a reduction in both muscle mass and total body water. The bioelectrical impedance vector analysis (BIVA) overcomes the limits imposed by bioelectrical impedance, since it only requires the resistance (R) and reactance (Xc) values, standardized by the individual's height, which makes the method more individualized and accurate. The aim of this study was to evaluate the body composition using the BIVA of the community-living older adults, with regard to sex and body mass index (BMI) classification, and compare the results with the reference population. METHODS: Cross-sectional study with the community-living older adults of both sexes. Bioimpedance was carried out and the R and Xc data analyzed, based on height, and plotted on RXc graphs. RESULTS: One hundred and forty-four older adults (n = 33 men; n = 111 women; mean age of 80.2 ± 9.2 years) participated in the study. Low weight (<23 kg/m2) was the most prevalent in BMI classification. The older adult women presented a higher average BMI, body fat percentage and R/Height values, while the older adult men presented a higher average for fat-free mass and the phase angle (p < 0.05). The older adult, regardless of their BMI, located in the right quadrant, indicated cachexia; those with low weight were dehydrated, and those with overweight (BMI ≥ 28 kg/m2) presented hyperhydration. CONCLUSION: The majority of the older adults with normal weight or overweight has impedance vectors indicating loss of muscle mass and water imbalance (dehydration or hyperhydration).

Effects of photobiomodulation therapy on the local experimental envenoming by Bothrops leucurus snake.

Bothrops leucurus is the major causative agent of snakebites in Brazil's Northeast. The systemic effects of its venom are effectively neutralized by antivenom therapy, preventing bitten patients' death. However, antivenom fails in neutralizing local effects that include intense pain, edema, bleeding, and myonecrosis. Such effects can lead to irreversible sequels, representing a clinically relevant issue for which there is no current effective treatment. Herein, the effects of photobiomodulation therapy (PBMT) were tested in the local actions induced by B. leucurus venom (BLV) in mice (n = 123 animals in 20 experimental groups). A continuous emission AlGaAs semiconductor diode laser was used in two wavelengths (660 or 780 nm). Mechanical nociceptive thresholds were assessed with the electronic von Frey apparatus. Local edema was determined by measuring the increase in paw thickness. Hemorrhage was quantified by digital measurement of the bleeding area. Myotoxicity was evaluated by serum creatine kinase (CK) activity and histopathological analysis. PBMT promoted anti-hypernociception in BLV-injected mice; irradiation with the 660 nm laser resulted in faster effect onset than the 780 nm laser. Both laser protocols reduced paw edema formation, whether irradiation was performed immediately or half an hour after venom injection. BLV-induced hemorrhage was not altered by PBMT. Laser irradiation delayed, but did not prevent myotoxicity caused by BLV, as shown by a late increase in CK activity and histopathological alterations. PBMT was effective in the control of some of the major local effects of BLV refractory to antivenom. It is a potential complementary therapy that could be used in bothropic envenoming, minimizing the morbidity of these snakebite accidents.