Development and Validation of Estimation Equations for Appendicular Skeletal Muscle Mass in Chinese Community-Dwelling Older Adults

Abstract

Purpose

This study aimed to establish equations for estimating muscle mass through anthropometric parameters or together with physical function parameters in the community-dwelling older adults, providing a simple way of muscle mass assessment.

Methods

In this cross-sectional descriptive study, a total of 1537 older adults were recruited from the community and accepted the measurements of height, weight, upper arm and calf circumferences, grip strength, and walking speed. Body composition including appendicular skeletal muscle mass (ASM) was measured using bioelectrical impedance analysis (BIA). Participants were randomly divided into the development or validation group. Stepwise multiple linear regression was applied to develop equations in the development group. Thereafter, Pearson correlation coefficients, Bland-Altman plots, paired t-test, intraclass correlation coefficient (ICC) and paired-samples t-tests were used to assess the validity of the equations.

Results

All parameters were significantly correlated with ASM (r = 0.195~0.795, P < 0.001) except for the age in the validation group (P = 0.746). The most optimal anthropometric equation was: [adjusted R² = 0.911, standard error of the estimate (SEE) = 1.311, P < 0.001]. Comparatively speaking, this equation showed high correlation coefficient (r = 0.951, P < 0.001) and ICC (ICC = 0.950, P < 0.001). No significant differences were found between BIA-measured ASM and the estimated ASM. The Bland-Altman plot showed that the mean difference between the estimated ASM and BIA-measured ASM was 0 kg and the limits of agreement of ASM was −2.70~2.60 kg. Furthermore, inclusion of physical function did not significantly improve the adjusted R² and SEE.

Conclusion

The anthropometric equation offers a practical alternative simple and dependable method for estimating ASM in community-dwelling older adults.

Keywords:

• appendicular muscle mass
• anthropometry
• physical function
• estimation equation
• older adults

Abbreviations

ASM, appendicular skeletal muscle mass; BIA, bioelectrical impedance analysis; DXA, dual-energy x-ray absorptiometry; ICC, intraclass correlation coefficient; BMI, body mass index; SEE, standard error of the estimate; LOA, limits of agreement; SD, standard deviation.

Data Sharing Statement

In attempt to preserve the privacy of individuals, clinical data will not be shared; the data can be available from the corresponding author on reasonable request authors upon request.

Ethics Approval and Consent to Participate

All participants were fully informed about the research purpose and characteristics before they provided signed consent. Ethical approval was granted from the Ethics Committee of Soochow University (ECSU-2019000161). This study conformed to the standards of the Declaration of Helsinki and was registered with Chinese Clinical Trial Registry (ChiCTR1900027960).

Acknowledgments

We would like to thank study participants who devoted their time and efforts.

Author Contributions

All authors made a significant contribution to the work reported, whether that is in the conception, study design, execution, acquisition of data, analysis and interpretation, or in all these areas; took part in drafting, revising or critically reviewing the article; gave final approval of the version to be published; have agreed on the journal to which the article has been submitted; and agree to be accountable for all aspects of the work.

Disclosure

The authors report no conflicts of interest in this work.

Additional information

Funding

This research was partially supported by grants from the Joint Research Project of Suzhou BenQ Medical Center and Suzhou Medical College of Soochow University (P112700322).