Sarcopenic indices in community-dwelling older adults

Ericka N. Merriwether, Helen H. Host, David R. Sinacore

Research output: Contribution to journalArticle

Abstract

Background: Sarcopenic indices are used to estimate loss of skeletal lean mass and function and to determine the prevalence of sarcopenic in older adults. It is believed that older women and men with lower skeletal lean mass will be weaker and have more functional limitations. Purpose: (1) To classify community-dwelling older adults using 2 common sarcopenic indices: appendicular lean mass/height2 (ALM/ht2) and skeletal muscle index (SMI), and (2) to determine each indices value as indicators of lower extremity strength and physical function. Methods: The sample consisted of 154 community-dwelling older adults (111 women and 43 men; mean age = 82.4, SD = 3.6 years; mean body mass index = 25.8, SD = 4.4 kg/m2). Each underwent whole-body dual-energy x-ray absorptiometry to assess lean mass. The 9-item modified Physica Performance Test and self-selected walking speed were used to evaluate function. Lower extremity strength was measured bilaterally using isokinetic dynamometry. Results: The ALM/ht 2 index classified 75 participants (49%) as SP and 79 (51%) as nonsarcopenic (NSP). The SMI classified 129 participants (84%) as SP and 25 (16%) as NSP. There were no differences in functional measures between groups by gender using either index after classification. The ALM/ht2 index was more strongly correlated with peak torque of all lower extremity muscle groups (r = 0.276-0.487) compared with the SMI (r = 0.103-0.344). There was no relationship between sarcopenic index and physical function. Discussion: There were marked differences in how 2 sarcopenic ndices classified community-dwelling older adults. Lower extremity strength was lower in older women classified as sarcopenic than NSP using the ALM/ht2 index, but lower extremity strength was not different in older men. However, no lower extremity strength differences were observed between SP and NSP men or women using the SMI classification. Neither sarcopenic index uniformly identified community-dwelling older adults with functional or strength deficits. Conclusions: Detection of strength deficits using sarcopenic indices alone may be gender-specific and may not reflect strength orfunctional decline in community-dwelling men aged 80 years or older. Given associations between lower extremity strength and physical function, strength measures remain a better predictor of physical performance than sarcopenic indices for community-dwelling older men and women.

Original languageEnglish (US)
Pages (from-to)118-125
Number of pages8
JournalJournal of Geriatric Physical Therapy
Volume35
Issue number3
DOIs
StatePublished - Jul 2012

Keywords

  • Lean mass
  • Older adults
  • Physical function
  • Strength

ASJC Scopus subject areas

  • Rehabilitation
  • Geriatrics and Gerontology

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