Shibata S1, Yamada T1
1Tokyo Metropolitan University, Tokyo, Japan
Background: Fall-related injuries among the elderly are common and present a serious public health crisis in Japan and other countries. Sarcopenia leads to an increased risk of falls. Bioelectrical impedance analysis (BIA) is effective as an assessment method for sarcopenia. Many studies have examined muscle mass, but very few have focused on muscle density, i.e., muscle fibers.
Purpose: This study aimed to clarify which factor had a greater influence on motor function of the lower limbs in the elderly: muscle density or muscle mass.
Methods: We measured the muscle density index (MDI), muscle cross-sectional area index (MCAI), impedance index (Z-Index), and one-leg standing time (OLST) in community-dwelling elderly people. A total of 30 volunteers (8 men and 22 women; mean age±SD: 76.4±4.4 years) were recruited in this study. MDI, MCAI, and Z-Index in the thigh and lower leg were measured by BIA (MSd-100; Tanita Corp., Japan). Subjects were classified into one of the following groups; healthy group (OLST≧15 sec) and unstable group (15 sec>OLST). Their MDI, MCAI, and Z-Index values were compared using the paired t-test.
The relationship between OLST and BIA data was analyzed using Spearman's correlation.
Relationships among the subject's age, OLST, and BIA data were analyzed using Pearson's correlation. This study protocol was approved by the ethics committee of the Tokyo Metropolitan University.
Results: MDI values in both the thigh and lower leg in the unstable group (thigh MDI (mean MDI±SD: 0.18±0.04) leg MDI (mean MDI±SD: 0.23±0.04)) were significantly lower than those in the healthy group (thigh MDI (mean MDI±SD: 0.23±0.04) leg MDI (mean MDI±SD: 0.27±0.04)).
There were significant correlations between the OLST for both the thigh MDI (r=0.431, p=0.019) and lower leg MDI (r=0.356, p=0.053). There was a significant correlation between age and OLST (r=-0.571, p=0.001). There was also a significant correlation between age and MDI (thigh: r=-0.488, p=0.007; leg: r=-0.440, p=0.015).
Conclusion(s): We found that muscle density has an effect on motor function in the elderly, and muscle density decreases with age. This study, thus, indicates that rehabilitation strategies for the elderly should focus on muscle density.
Implications: This study implies that provision of a new fall risk index for healthcare workers would be beneficial.
Keywords: muscle density, fall risk index, one leg standing
Funding acknowledgements: The authors declare no conflicts of interest associated with this manuscript.
Purpose: This study aimed to clarify which factor had a greater influence on motor function of the lower limbs in the elderly: muscle density or muscle mass.
Methods: We measured the muscle density index (MDI), muscle cross-sectional area index (MCAI), impedance index (Z-Index), and one-leg standing time (OLST) in community-dwelling elderly people. A total of 30 volunteers (8 men and 22 women; mean age±SD: 76.4±4.4 years) were recruited in this study. MDI, MCAI, and Z-Index in the thigh and lower leg were measured by BIA (MSd-100; Tanita Corp., Japan). Subjects were classified into one of the following groups; healthy group (OLST≧15 sec) and unstable group (15 sec>OLST). Their MDI, MCAI, and Z-Index values were compared using the paired t-test.
The relationship between OLST and BIA data was analyzed using Spearman's correlation.
Relationships among the subject's age, OLST, and BIA data were analyzed using Pearson's correlation. This study protocol was approved by the ethics committee of the Tokyo Metropolitan University.
Results: MDI values in both the thigh and lower leg in the unstable group (thigh MDI (mean MDI±SD: 0.18±0.04) leg MDI (mean MDI±SD: 0.23±0.04)) were significantly lower than those in the healthy group (thigh MDI (mean MDI±SD: 0.23±0.04) leg MDI (mean MDI±SD: 0.27±0.04)).
There were significant correlations between the OLST for both the thigh MDI (r=0.431, p=0.019) and lower leg MDI (r=0.356, p=0.053). There was a significant correlation between age and OLST (r=-0.571, p=0.001). There was also a significant correlation between age and MDI (thigh: r=-0.488, p=0.007; leg: r=-0.440, p=0.015).
Conclusion(s): We found that muscle density has an effect on motor function in the elderly, and muscle density decreases with age. This study, thus, indicates that rehabilitation strategies for the elderly should focus on muscle density.
Implications: This study implies that provision of a new fall risk index for healthcare workers would be beneficial.
Keywords: muscle density, fall risk index, one leg standing
Funding acknowledgements: The authors declare no conflicts of interest associated with this manuscript.
Topic: Health promotion & wellbeing/healthy ageing; Primary health care
Ethics approval required: Yes
Institution: Tokyo Metropolitan University
Ethics committee: Research Safety Ethics Review Committee of the Tokyo Metropolitan University
Ethics number: 17081
All authors, affiliations and abstracts have been published as submitted.
