Validation of population-based cutoffs for low muscle mass and strength in a population of Turkish elderly adults
Background Despite differences between the studies regarding methods for estimating low muscle mass, the European Working Group on Sarcopenia in Older People (EWGSOP) recommends use of two standard deviations (SDs) below the reference sex-specific means of healthy young adults. Aims The aim of this study was to determine the cutoff points of skeletal muscle mass index (SMI) and handgrip strength (HS) in Turkish population and to compare the power of different cutoff points to predict comprehensive geriatric assessment (CGA) parameters. Methods Two hundred and eight young healthy volunteers (104 women, 104 men) were included in the study to define SMI, HS cutoff values. 1150 older adults (784 women, 366 men) underwent CGA, including physical performance, activities of daily living (ADL), HS and frailty. Body composition was obtained from every participant by bioimpedance analysis (BIA). CGA parameters of sarcopenic patients according to EWGSOP and new Turkish cutoff points were compared. Results SMI cutoff points were defined 5.70 kg/m(2) for women, 8.33 kg/m(2) for men. HS thresholds were calculated as 14 kg for women, 28 kg for men using measurements of healthy young adult reference. Considering the new threshold values, the prevalence of sarcopenia was 10% (7% women, 17% men). When new sarcopenia criteria were applied and covariates were adjusted, sarcopenia was found to be more closely related to ADL impairment, balance, frailty in men, and balance, slow walking speed, ADL impairment, frailty in women (p < 0.05). Discussion Muscle mass and strength may vary between populations because of ethnicity and other related discrepancies. The evaluation of sarcopenia according to the present guidelines may cause overdiagnosis in some populations. Conclusion Cutoff points specific to populations should be determined.