Cutpoints for Low Appendicular Lean Mass That Identify Older Adults With Clinically Significant Weakness

    Authors

    P. M. Cawthon; K. W. Peters; M. D. Shardell; R. R. McLean; T. T. L. Dam; A. M. Kenny; M. S. Fragala; T. B. Harris; D. P. Kiel; J. M. Guralnik; L. Ferrucci; S. B. Kritchevsky; M. T. Vassileva; S. A. Studenski;D. E. Alley

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    Abbreviated Journal Title

    J. Gerontol. Ser. A-Biol. Sci. Med. Sci.

    Keywords

    Muscle; Sarcopenia; Cutpoints; BONE-MINERAL DENSITY; ALTERNATIVE DEFINITIONS; PHYSICAL FUNCTION; MUSCLE; STRENGTH; WHITE WOMEN; MEN; SARCOPENIA; HEALTH; RISK; PERFORMANCE; Geriatrics & Gerontology; Gerontology

    Abstract

    Low lean mass is potentially clinically important in older persons, but criteria have not been empirically validated. As part of the FNIH (Foundation for the National Institutes of Health) Sarcopenia Project, this analysis sought to identify cutpoints in lean mass by dual-energy x-ray absorptiometry that discriminate the presence or absence of weakness (defined in a previous report in the series as grip strength < 26kg in men and < 16kg in women). In pooled cross-sectional data stratified by sex (7,582 men and 3,688 women), classification and regression tree (CART) analysis was used to derive cutpoints for appendicular lean body mass (ALM) that best discriminated the presence or absence of weakness. Mixed-effects logistic regression was used to quantify the strength of the association between lean mass category and weakness. In primary analyses, CART models identified cutpoints for low lean mass (ALM < 19.75kg in men and < 15.02kg in women). Sensitivity analyses using ALM divided by body mass index (BMI: ALM(BMI)) identified a secondary definition (ALM(BMI) < 0.789 in men and ALM(BMI) < 0.512 in women). As expected, after accounting for study and age, low lean mass (compared with higher lean mass) was associated with weakness by both the primary (men, odds ratio [OR]: 6.9 [95% CI: 5.4, 8.9]; women, OR: 3.6 [95% CI: 2.9, 4.3]) and secondary definitions (men, OR: 4.3 [95% CI: 3.4, 5.5]; women, OR: 2.2 [95% CI: 1.8, 2.8]). ALM cutpoints derived from a large, diverse sample of older adults identified lean mass thresholds below which older adults had a higher likelihood of weakness.

    Journal Title

    Journals of Gerontology Series a-Biological Sciences and Medical Sciences

    Volume

    69

    Issue/Number

    5

    Publication Date

    1-1-2014

    Document Type

    Article

    Language

    English

    First Page

    567

    Last Page

    575

    WOS Identifier

    WOS:000334738000009

    ISSN

    1079-5006

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