Influence of aging on extracellular water-to-total body water ratio in community-dwelling females.

BACKGROUND & AIMS: The European Working Group of Sarcopenia in Older People 2 has emphasized the significance of evaluating not only muscle mass but also muscle quality as a diagnostic criterion for sarcopenia. The extracellular water-to-total body water ratio (ECW/TBW), measured using bioelectrical impedance analysis (BIA), has recently received attention as an indicator of muscle quality. However, the influence of aging on the ECW/TBW remains unclear. If ECW/TBW increases with age, it is important to know whether the timing of the decrease in SMI and the increase in ECW/TBW are the same or different. This study aimed to investigate the influence of aging on ECW/TBW in community-dwelling females. METHODS: This cross-sectional study included 237 community-dwelling females aged 20-89 years who could perform activities of daily living independently. ECW/TBW and SMI were measured using BIA. Multiple linear regression analyses of ECW/TBW and SMI were conducted. Age, body mass index (BMI), number of medications, pain, and medical history were considered independent variables in the multiple linear regression. The participants were divided into three (20-39, 40-64, and 65-89 years) or four (20-39, 40-64, 65-74, and 75-89 years) groups based on age. Analysis of covariance adjusted for the BMI, number of medications, pain, and medical history was conducted to determine the differences in ECW/TBW and SMI among the three or four groups. RESULTS: In the multiple linear regression analysis, age was significantly and independently associated with ECW/TBW and SMI. When the participants were divided into three groups based on age, an increase in ECW/TBW and a decrease in SMI in the 65-89-year group were confirmed compared with the 20-39 and 40-64-year groups. When the participants were divided into four groups based on age, an increase in ECW/TBW in the 75-89-year group was confirmed compared with the 65-74-year group. However, there were no significant differences in SMI among the four groups. CONCLUSIONS: This study revealed that ECW/TBW increases with aging in community-dwelling females. Moreover, the negative influences of aging were confirmed earlier in ECW/TBW than in SMI. Assessing muscle mass alone may not be adequate to capture the influences of aging on muscle composition, and evaluating ECW/TBW may be crucial for diagnosing sarcopenia.

Extracellular water-to-total body water ratio is an essential confounding factor in bioelectrical impedance analysis for sarcopenia diagnosis in women.

PURPOSE: The extracellular water-to-total body water ratio (ECW/TBW) is used in bioelectrical impedance analysis (BIA) for measuring muscle mass; however, ECW/TBW may be affected by several factors common in older individuals. Here, we assessed the relationships of ECW/TBW with handgrip strength, gait speed, and skeletal muscle mass index (SMI) in older women. METHODS: In this cross-sectional study, 73 community-dwelling women aged ≥ 65 years who could independently perform activities of daily living were included. ECW/TBW was measured using direct segmental multifrequency BIA. The participants were divided into ECW/TBW < 0.40 (n = 54) and ECW/TBW ≥ 0.40 (n = 19) groups, with the latter indicating overhydration. SMI was calculated as appendicular skeletal muscle mass/(height)2 (kg/m2). The relationships of SMI with handgrip strength and gait speed were assessed using partial correlation coefficients. Age, number of medications, pain, and medical history were treated as control variables. RESULTS: The average age of participants was 77.6 ± 6.0 years. The SMI was significantly related to handgrip strength (partial correlation coefficient = 0.293, P = 0.016) but not to gait speed (partial correlation coefficient = - 0.183, P = 0.138). Similarly, the SMI of the ECW/TBW < 0.40 group was significantly related to handgrip strength (partial correlation coefficient = 0.372, P = 0.009) but not gait speed (partial correlation coefficient = - 0.267, P = 0.066); however, the SMI of the ECW/TBW ≥ 0.40 group was not related to either variable. CONCLUSION: ECW/TBW represents a confounding factor, which should be considered when using BIA for sarcopenia diagnosis.

Increased total body extracellular-to-intracellular water ratio in community-dwelling elderly women is associated with decreased handgrip strength and gait speed.

OBJECTIVE: As the extracellular-to-intracellular water (ECW/ICW) ratio of the thigh is negatively associated with knee extension strength or gait speed in the elderly, an increase in the total body ECW/ICW ratio in the elderly is considered to be related to a decrease in physical function. However, these relationships have not been properly investigated. The aim of this study was to investigate the relationship of handgrip strength and gait speed with the total body ECW/ICW ratio in community-dwelling elderly women. METHODS: The present study used a cross-sectional design. We enrolled 71 community-dwelling women, ≥65 y of age, who could independently perform activities of daily living. The total body ECW/ICW ratio was measured using bioelectrical impedance analysis. Relationships between the total body ECW/ICW ratio and grip strength and gait speed were assessed using Pearson's correlation coefficient. Additionally, stepwise multiple regression analysis was used to identify the factors that were independently associated with handgrip strength and gait speed. The independent variables considered were the total body ECW/ICW ratio, age, body mass index, number of medications, presence of pain, and a history of certain conditions. RESULTS: The results indicated that an increased total body ECW/ICW ratio in community-dwelling elderly women was associated with a decreased handgrip strength and gait speed. Furthermore, the total body ECW/ICW ratio was significantly, independently associated with handgrip strength even after adjusting for confounding factors. CONCLUSION: These findings suggest that the total body ECW/ICW ratio may indicate health conditions in community-dwelling elderly women.

Changes in Quadriceps Thickness and Echo Intensity in Chronic Stroke Survivors: A 3-Year Longitudinal Study.

OBJECTIVES: The aim of the current study was to examine longitudinal changes in quadriceps muscle mass and intramuscular adipose tissue in chronic stroke survivors. MATERIALS AND METHODS: In this longitudinal study included 34 chronic stroke survivors who lived in the community. Ultimately, 20 chronic stroke survivors received an after 3-year assessment. Fourteen chronic stroke survivors were lost at follow-up. Chronic stroke survivors who were followed and not followed during 3 years were categorized as follow-up group and lost follow-up group, respectively. The quadriceps muscle mass and intramuscular adipose tissue were assessed at baseline and after 3-year assessments based on muscle thickness and echo intensity in ultrasound images, respectively. RESULTS: No significant differences in any characteristics were observed between the flow-up and lost follow-up groups. In the follow-up group, there was a significant decrease in quadriceps thickness on the paretic (10.3% decrease) and non-paretic (17.0% decrease) sides at follow-up after 3 years compared with baseline. There was a significant increase in quadriceps echo intensity on the paretic (20.0% increase) and non-paretic (24.9% increase) sides at follow-up after 3 years compared with baseline. There were significant positive relationships between changes in body weight and changes in quadriceps thickness on the paretic and non-paretic sides. Chronic stroke survivors with greater reductions in body weight showed a trend towards a greater decrease in quadriceps thickness on the paretic and non-paretic sides. CONCLUSIONS: The current results suggest marked longitudinal changes in the skeletal muscles in chronic stroke survivors. Preventing secondary changes in skeletal muscles and limiting decreases in body weight are essential for improving outcomes in chronic stroke survivors.

Higher malnutrition risk is related to increased intramuscular adipose tissue of the quadriceps in older inpatients: A cross-sectional study.

BACKGROUND & AIMS: The relationship between malnutrition risk and intramuscular adipose tissue of the quadriceps in older inpatients remains unclear, although a high rate of malnutrition risk has been observed in these patients. Understanding this relationship would be necessary for a management plans for older inpatients. This study aimed to examine the relationship between malnutrition risk and intramuscular adipose tissue of the quadriceps in older inpatients. METHODS: Three-hundred and twenty-three older inpatients participated in this cross-sectional study. Malnutrition risk was assessed using the Geriatric Nutritional Risk Index (GNRI). Intramuscular adipose tissue of the quadriceps was assessed based on ultrasound echo intensity. Higher echo-intensity indicates greater amounts of intramuscular adipose tissue. Multiple regression analysis was used to identify the factors that were independently associated with quadriceps echo intensity. GNRI, age, sex (male = 1, female = 2), number of medications, C-reactive protein, updated Charlson comorbidity index, Food Intake Level Scale, the subcutaneous fat thickness of the thigh, motor-Functional Independence Measures, and length of hospital stay were set as the independent variables. RESULTS: GNRI (ß = -0.18), age (ß = 0.18), sex (ß = 0.22), number of medications (ß = 0.09), the subcutaneous fat thickness of the thigh (ß = -0.29), motor-FIM (ß = -0.12), and length of hospital stay (ß = 0.11) were significantly and independently associated with the quadriceps echo intensity. CONCLUSIONS: The current results revealed that higher malnutrition risk was associated with increased intramuscular adipose tissue of the quadriceps of older inpatients even after adjusting for other characteristics. Nutritional intervention may be necessary for decreasing intramuscular adipose tissue of the quadriceps in older inpatients who have higher malnutrition risk.

Quantitative features of intramuscular adipose tissue of the quadriceps and their association with gait independence in older inpatients: A cross-sectional study.

OBJECTIVE: The aim of this study was to examine the quantitative features of intramuscular adipose tissue of the quadriceps and their association with gait independence in older inpatients. METHODS: This was a cross-sectional study with 216 inpatients ≥65 y of age. We also recruited 40 community-dwelling healthy individuals in the same age group who were able to walk independently for matched-pair analysis to determine the quantitative features of intramuscular adipose tissue in older inpatients. Participants were assigned to total assistance (Functional Independence Measure [FIM] gait score 1 or 2), partial assistance (FIM gait score 3-5), and independent (FIM gait score 6 or 7) groups. Ultrasound images were acquired using B-mode ultrasound imaging. Intramuscular adipose tissue and muscle mass of the quadriceps were assessed based on echo intensity and muscle thickness, respectively. RESULTS: Echo intensity of the quadriceps of older inpatients was increased to ~1.66 times that of matched healthy older people. Echo intensity of the independent group was significantly lower than that of the total and partial assistance groups. No differences were found in quadricep thickness among the three groups. CONCLUSIONS: The results from the present study suggested that intramuscular adipose tissue of the quadriceps of older inpatients was increased to ~1.7 times that of healthy older individuals matched for demographic characteristics. More intramuscular adipose tissue of the quadriceps was observed among older inpatients who were unable to walk independently compared with older inpatients who were able to walk independently.

Dysphagia is more strongly associated with increased intramuscular adipose tissue of the quadriceps than with loss of muscle mass in older inpatients.

The purpose of this study was to examine the relationship between intramuscular adipose tissue of the quadriceps and dysphagia in older inpatients. We hypothesized that increased intramuscular adipose tissue of the thigh may indirectly reflect severe dysphagia in older inpatients. This study was cross-sectional, and 103 older inpatients participated. Patients who had stroke that was the obvious cause of dysphagia were excluded. Primary outcomes were intramuscular adipose tissue of the quadriceps and severity of dysphagia. Transverse ultrasound images were acquired using B-mode ultrasound imaging. Intramuscular adipose tissue and muscle mass of the quadriceps were assessed based on echo intensity and muscle thickness, respectively. Severity of dysphagia was assessed using the Food Intake Level Scale (FILS). We used multiple regression analysis to identify the factors that were independently associated with FILS scores. Echo intensity, age, sex, body mass index, number of medications, C-reactive protein, Geriatric Nutritional Risk Index (GNRI), updated Charlson Comorbidity Index, muscle thickness, subcutaneous fat thickness of the thigh, and length of hospital stay were the independent variables. Echo intensity (ß = -0.28), number of medications (ß = 0.22), GNRI (ß = 0.27), and subcutaneous fat thickness of the thigh (ß = -0.29) were significantly independently associated with FILS scores. Muscle thickness was not significantly independently related to FILS scores (ß = 0.08). In conclusion, our results suggest that increased intramuscular adipose tissue of the quadriceps in older inpatients is associated with dysphagia. Furthermore, this relationship was stronger than that between loss of muscle mass and dysphagia.

Low body mass index negatively affects muscle mass and intramuscular fat of chronic stroke survivors.

OBJECTIVE: Relationship between secondary changes in skeletal muscle and body weight in chronic stroke survivors has not yet been carefully examined. The objective of this study was to clarify the relationships between muscle mass, intramuscular fat, and body weight in chronic stroke survivors. METHODS: Seventy-two chronic stroke survivors participated in this study. Transverse ultrasound images were acquired using B-mode ultrasound imaging. Quadriceps muscle mass and intramuscular fat were assessed based on muscle thickness and echo intensity, respectively. We used a stepwise multiple regression analysis to identify the factors that were independently associated with the body mass index. We entered quadriceps thickness and echo intensity of the paretic and non-paretic sides into another stepwise multiple regression model to avoid multicollinearity. Age, sex, type of stroke, time since stroke, thigh length, number of medications, and an updated Charlson comorbidity index were included as the independent variables. RESULTS: The quadriceps thickness and echo intensity of the paretic and non-paretic sides were significantly independently associated with the body mass index: quadriceps thickness of the paretic side, ß = 0.52; quadriceps thickness of the non-paretic side, ß = 0.55; quadriceps echo intensity of the paretic side, ß = -0.35; quadriceps echo intensity of the non-paretic side, ß = -0.27). CONCLUSIONS: Our results suggest that low body mass index is associated with loss of muscle mass and increased intramuscular fat on both the paretic and non-paretic sides of chronic stroke survivors. Further studies examining whether appropriate weight management, along with targeted rehabilitation programs aimed at increasing muscle mass and decreasing intramuscular fat, achieves good outcomes in chronic stroke survivors are warranted.

Muscle mass and intramuscular fat of the quadriceps are related to muscle strength in non-ambulatory chronic stroke survivors: A cross-sectional study.

OBJECTIVE: Improving muscle mass and intramuscular fat in the mid-thigh increases the muscle strength of the paretic and non-paretic limbs in ambulatory chronic stroke survivors. There is a remarkable decrease in muscle mass and muscle strength and an increase in intramuscular fat in the quadriceps of both limbs of non-ambulatory compared with ambulatory survivors. Therefore, given that paretic lower extremity function does not recover sufficiently in the chronic phase, it may be helpful to improve muscle mass and intramuscular fat to increase muscle strength in the quadriceps of non-ambulatory chronic stroke survivors. However, these relationships remain unclear. The purpose of this study was to clarify the relationships between muscle strength, muscle mass, and intramuscular fat of the quadriceps in non-ambulatory chronic stroke survivors. METHODS: Study design: A cross-sectional study. Participants: Fifty non-ambulatory chronic stroke survivors. Main outcome measures: Quadriceps muscle strength was measured using a handheld dynamometer. Transverse ultrasound images were acquired using B-mode ultrasound imaging. Muscle mass and intramuscular fat of the quadriceps were assessed based on muscle thickness and echo intensity, respectively. Data analysis: Stepwise multiple regression analyses were used to identify the factors independently associated with the quadriceps muscle strength of the paretic and non-paretic limbs. To avoid multicollinearity, muscle thickness and echo intensity were entered into separate multiple regression models. Muscle thickness or echo intensity of the paretic or non-paretic limbs and other confounding factors were set as the independent variables. RESULTS: Muscle thickness was positively related and echo intensity was negatively related to the quadriceps muscle strength of the paretic and non-paretic limbs. CONCLUSIONS: Muscle mass and intramuscular fat of the quadriceps are related to muscle strength in non-ambulatory chronic stroke survivors. Increasing muscle mass and decreasing intramuscular fat of the quadriceps of both limbs may improve muscle strength.

Relationships between muscle mass, intramuscular adipose and fibrous tissues of the quadriceps, and gait independence in chronic stroke survivors: a cross-sectional study.

OBJECTIVE: To examine the relationships between muscle mass, intramuscular adipose and fibrous tissues of the quadriceps, and gait independence in chronic stroke survivors. DESIGN: Cross-sectional study. SETTING: Hospital-based research. PARTICIPANTS: Seventeen chronic stroke survivors who were unable to walk independently (non-independent walker group) and 11 chronic stroke survivors who were able to walk independently (independent walker group) participated in this study. In addition, 25 healthy older adults (healthy group) were enrolled. INTERVENTIONS: None. MAIN OUTCOME MEASURES: The muscle mass and intramuscular adipose and fibrous tissues of the rectus femoris and vastus intermedius were assessed based on muscle thickness and echo intensity of ultrasound images, respectively. RESULTS: The thicknesses of the rectus femoris and vastus intermedius on the paretic and non-paretic sides in the non-independent walker group were significantly lower than those in the healthy group (mean difference -0.5 to -0.2cm; P<0.001-0.037). The paretic side in the non-independent walker group had significantly higher rectus femoris and vastus intermedius echo intensity compared with the healthy group (mean difference 15.8-17.4; P=0.007-0.025). The thickness of the rectus femoris on the non-paretic side was significantly lower in the independent walker group than in the healthy group (mean difference -0.3cm; P=0.001). CONCLUSIONS: These results suggest that chronic stroke survivors who are unable to walk independently are likely to experience secondary changes in skeletal muscle on both the paretic and non-paretic sides.

Determining the cut-off value for knee extensor strength for identifying independence in gait in chronic stroke survivors.

OBJECTIVE: To determine the cut-off values for knee extensor strength on the paretic and non-paretic sides and both sides combined for identifying independence in gait in chronic stroke survivors. DESIGN: Cross-sectional study. PATIENTS: Sixty chronic stroke survivors. METHODS: Functional Independence Measure (FIM) gait scores were measured, and the participants were allocated to the independent group (FIM gait score 6 or 7) or the dependent group (FIM gait score 1-5). Knee extensor strength on the paretic and non-paretic sides was measured using a handheld dynamometer. RESULTS: Eighteen stroke survivors were allocated to the independent group and 42 to the dependent group. The receiver operating characteristic curve analyses revealed that the cut-off values for knee extensor strength were 0.46 Nm/kg (sensitivity 83% and specificity 67%; area under the curve (AUC) 0.816) on the paretic side, 0.65 Nm/kg (sensitivity 89% and specificity 55%; AUC 0.738) on the non-paretic side and 1.31 Nm/kg (sensitivity 83% and specificity 74%; AUC 0.811) for both sides combined. CONCLUSION: These cut-off values could help to identify stroke survivors who are no longer independent in gait because of decreasing knee extensor strength on the paretic and non-paretic sides.

Relationships between intramuscular fat, muscle strength and gait independence in older women: A cross-sectional study.

AIM: The objectives of the present study were to examine the relationships between intramuscular fat, muscle strength and gait independence, as well as to clarify the intramuscular fat characteristics of dependent older women. METHODS: A total of 25 older women who were unable to walk with or without assistance (dependent group), 22 frail older women (frail group) and 22 healthy older women (healthy group) participated in the present study. The frail participants could walk independently, but showed three or more of the following characteristics: slowness, weakness, weight loss, exhaustion and low physical activity. Outcome measures were quadriceps intramuscular fat determined by ultrasound echo intensity, and quadriceps muscle strength of the dependent, frail and healthy groups. In addition, the degree of gait independence (functional independence measures gait score) was assessed in the dependent and frail groups. RESULTS: Echo intensity in the dependent group was significantly negatively correlated with muscle strength and the functional independence measure gait score (correlation coefficients -0.635 and -0.344, respectively). Furthermore, echo intensity in the dependent group was significantly higher than in the healthy group. There was no significant difference in echo intensity between the dependent and frail groups. CONCLUSIONS: The present results suggest negative relationships between intramuscular fat and muscle strength, and intramuscular fat and degree of gait independence in dependent older women. In addition, dependent older women have more intramuscular fat than healthy older women. Geriatr Gerontol Int 2017; 17: 1683-1688.

Effects of long-term self-massage at the musculotendinous junction on hamstring extensibility, stiffness, stretch tolerance, and structural indices: A randomized controlled trial.

OBJECTIVES: The purpose of this study was to examine the effect of long-term self-massage at the musculotendinous junction on hamstring extensibility, stiffness, stretch tolerance, and structural indices. DESIGN: Single-blind, randomized, controlled trial. SETTING: Laboratory. PARTICIPANTS: Thirty-seven healthy men. INTERVENTION: The right or left leg of each participant was randomly assigned to the massage group, and the other leg was assigned to the control group. The participants conducted self-massage at the musculotendinous junction for 3 min daily, five times per week, for 12 weeks. MAIN OUTCOME MEASURES: Hamstring extensibility, stiffness, stretch tolerance, and structural indices were measured by a blinded examiner prior to the massage intervention and after 6 and 12 weeks of intervention. RESULTS: The maximum hip flexion angle (HFA) and the maximum passive pressure after 6 and 12 weeks of intervention in the massage group were significantly higher than prior to intervention. The visual analog scale (for pain perception) at maximum HFA, the stiffness of the hamstring, and the structural indices did not differ in either group over the 12 week period. CONCLUSIONS: Our results suggest that long-term self-massage at the musculotendinous junction increases hamstring extensibility by improving stretch tolerance. However, this intervention does not change hamstring stiffness. CLINICAL TRIAL REGISTRATION NUMBER: University Hospital Medical Information Network registration number UMIN000011233.