Sarcopenic indices in community-dwelling older adults

Area of Science:

• Gerontology
• Sarcopenia Research
• Biomedical Engineering

Background:

• Sarcopenic (SP) indices estimate skeletal muscle loss and functional decline in aging populations.
• Prevalence of SP is significant in older adults, impacting strength and physical function.
• Lower skeletal lean mass is generally associated with reduced strength and functional limitations.

Purpose of the Study:

• Classify community-dwelling older adults using appendicular lean mass/height² (ALM/ht²) and skeletal muscle index (SMI).
• Evaluate the effectiveness of ALM/ht² and SMI as indicators of lower extremity strength and physical function.

Main Methods:

• 154 community-dwelling older adults (mean age 82.4 years) underwent DXA for lean mass assessment.
• Lower extremity strength measured via isokinetic dynamometry; physical function assessed using the modified Physical Performance Test and walking speed.
• Participants classified as sarcopenic (SP) or non-sarcopenic (NSP) based on ALM/ht² and SMI indices.

Main Results:

• ALM/ht² classified 49% as SP, while SMI classified 84% as SP.
• No significant functional differences observed between SP and NSP groups by gender with either index.
• ALM/ht² showed stronger correlations with lower extremity muscle strength (peak torque) than SMI.
• No relationship found between SP index classification and physical function.

Conclusions:

• Significant discrepancies exist in sarcopenia classification between ALM/ht² and SMI indices.
• ALM/ht² identified lower extremity strength deficits in older women, but not men; SMI showed no strength differences.
• Sarcopenia indices alone may not uniformly identify strength or functional deficits, potentially being gender-specific.
• Direct strength measures are more reliable predictors of physical performance than sarcopenia indices in older adults.