Identification of Sarcopenia Components That Discriminate Slow Walking Speed: A Pooled Data Analysis

Collective Weakness Is Associated With Time to Mortality in Americans

ABSTRACT

McGrath, R, McGrath, BM, Jurivich, D, Knutson, P, Mastrud, M, Singh, B, and Tomkinson, GR. Collective weakness is associated with time to mortality in Americans. J Strength Cond Res 38(7): e398-e404, 2024-Using new weakness cutpoints individually may help estimate time to mortality, but their collective use could improve value. We sought to determine the associations of (a) each absolute and body size normalized cut point and (b) collective weakness on time to mortality in Americans. The analytic sample included 14,178 subjects aged ≥50 years from the 2006-2018 waves of the Health and Retirement Study. Date of death was confirmed from the National Death Index. Handgrip dynamometry measured handgrip strength (HGS). Men were categorized as weak if their HGS was <35.5 kg (absolute), <0.45 kg·kg -1 (body mass normalized), or <1.05 kg·kg -1 ·m -2 (body mass index [BMI] normalized). Women were classified as weak if their HGS was <20.0 kg, <0.337 kg·kg -1 , or <0.79 kg·kg -1 ·m -2 . Collective weakness categorized persons as below 1, 2, or all 3 cutpoints. Cox proportional hazard regression models were used for analyses. Subject values below each absolute and normalized cutpoint for the 3 weakness parameters had a higher hazard ratio for early all-cause mortality: 1.45 (95% confidence interval [CI]: 1.36-1.55) for absolute weakness, 1.39 (CI: 1.30-1.49) for BMI normalized weakness, and 1.33 (CI: 1.24-1.43) for body mass normalized weakness. Those below 1, 2, or all 3 weakness cut points had a 1.37 (CI: 1.26-1.50), 1.47 (CI: 1.35-1.61), and 1.69 (CI: 1.55-1.84) higher hazard for mortality, respectively. Weakness determined by a composite measure of absolute and body size adjusted strength capacity provides robust prediction of time to mortality, thus potentially informing sports medicine and health practitioner discussions about the importance of muscle strength during aging.

Collective Weakness and Fluidity in Weakness Status Associated With Basic Self-Care Limitations in Older Americans

Aims

To examine the associations of 1) absolute and normalized weakness cut-points, 2) collective weakness categories, and 3) changes in weakness status on future activities of daily living (ADL) limitations in older Americans.

Methods

The analytic sample included 11,656 participants aged ≥65-years from the 2006-2018 waves of the Health and Retirement Study. ADL were self-reported. A handgrip dynamometer measured handgrip strength (HGS). Males were classified as weak if their HGS was <35.5-kg (absolute), <0.45-kg/kg (body mass normalized), or <1.05-kg/kg/m2 (body mass index (BMI) normalized); females were considered weak if their HGS was <20.0-kg, <0.337-kg/kg, or <0.79-kg/kg/m2. Collective weakness categorized those below 1, 2, or all 3 absolute and normalized cut-points. These collective categories were also used to classify observed changes in weakness status over time (onset, persistent, progressive, recovery).

Results

Older Americans below absolute and normalized weakness cut-points had greater future ADL limitations odds: 1.34 (95% confidence interval (CI): 1.22-1.47) for absolute, 1.36 (CI: 1.24-1.50) for BMI normalized, and 1.56 (CI: 1.41-1.73) for body mass normalized. Persons below 1, 2, or 3 cut-points had 1.36 (CI: 1.19-1.55), 1.60 (CI: 1.41-1.80), and 1.70 (CI: 1.50-1.92) greater odds for future ADL limitations, respectively. Those in each changing weakness classification had greater future ADL limitation odds: 1.28 (CI: 1.01-1.62) for onset, 1.53 (CI: 1.22-1.92) for persistent, 1.72 (CI: 1.36-2.19) for progressive, and 1.34 (CI: 1.08-1.66) for recovery.

Conclusions

The presence of weakness, regardless of cut-point and change in status over time, was associated with greater odds for future ADL limitations.

Ambient air pollution exposure and the risk of probable sarcopenia: A prospective cohort study

BACKGROUND

Sarcopenia is characterized by decreased muscle mass and strength, posing threat to quality of life. Air pollutants are increasingly recognized as risk factors for diseases, while the relationship between the two remains to be elucidated. This study investigated whether exposure to ambient air pollution contributes to the development of sarcopenia.

METHODS

We employed the data from the UK Biobank with 303,031 eligible participants. Concentrations of PM2·5, NO2, and NOx were estimated. Cox proportional hazard regression models were applied to investigate the associations between pollutants and sarcopenia.

RESULTS

30,766 probable sarcopenia cases was identified during the follow-up. We observed that exposure to PM2.5 (HR, 1.232; 95% CI, 1.053-1.440), NO2 (HR, 1.055; 95% CI, 1.032-1.078) and NOx (HR, 1.016; 95% CI, 1.007-1.026) were all significantly associated with increased risk for probable sarcopenia for each 10 μg/m3 increase in pollutant concentration. In comparison with individuals in the lowest quartiles of exposure, those in the upper quartiles had significantly increased risk of probable sarcopenia. Sarcopenia-related factors, e.g., reduced lean muscle mass, diminished walking pace, and elevated muscle fat infiltration ratio, also exhibited positive associations with exposure to ambient air pollution. On the contrary, high level physical activity significantly mitigated the influence of air pollutants on the development of probable sarcopenia.

CONCLUSIONS

Air pollution exposure elevated the risk of developing sarcopenia and related manifestations in a dose-dependent manner, while physical activity maintained protective under this circumstance. Efforts should be made to control air pollution and emphasize the importance of physical activity for skeletal muscle health under this circumstance.

A Critical Review of Current Worldwide Definitions of Sarcopenia

With the increasing number of elderly individuals worldwide, the prevalence of age-related loss of muscle mass, referred to as sarcopenia, is expected to increase. Sarcopenia is a relatively new recognized syndrome, which is thought to affect 13% individuals worldwide, and the significant efforts made by different groups have advanced our understanding of the diagnosis, treatment, and natural history of this condition. However, the challenge is now to standardize its measurement and diagnosis to facilitate research in this area and a greater understanding of this condition and its management between clinicians and researchers. The Global Leadership Initiative on Sarcopenia (GLIS) is at the forefront of an international effort to produce standardized definition of sarcopenia. Setting a definition for sarcopenia entails several considerations and trade-offs. In this critical review, we have addressed key challenges driving the process of standardizing the definition, while delving into future avenues in sarcopenia research. Establishing a clear consensus on the working definition of sarcopenia is essential not only for advancing research in this field but also for assessing the prognostic implications of diagnosing sarcopenia and determining the most suitable treatment for affected patients.

Predicting Slow Walking Speed From a Pooled Cohort Analysis: Sarcopenia Definitions, Agreement, and Prevalence in Australia and New Zealand

BACKGROUND

Recent operational definitions of sarcopenia have not been replicated and compared in Australia and New Zealand (ANZ) populations. We aimed to identify sarcopenia measures that discriminate ANZ adults with slow walking speed (<0.8 m/s) and determine the agreement between the Sarcopenia Definitions and Outcomes Consortium (SDOC) and revised European Working Group for Sarcopenia in Older People (EWGSOP2) operational definitions of sarcopenia.

METHODS

Eight studies comprising 8 100 ANZ community-dwelling adults (mean age ± standard deviation, 62.0 ± 14.4 years) with walking speed, grip strength (GR), and lean mass data were combined. Replicating the SDOC methodology, 15 candidate variables were included in sex-stratified classification and regression tree models and receiver operating characteristic curves on a pooled cohort with complete data to identify variables and cut points discriminating slow walking speed (<0.8 m/s). Agreement and prevalence estimates were compared using Cohen's Kappa (CK).

RESULTS

Receiver operating characteristic curves identified GR as the strongest variable for discriminating slow from normal walking speed in women (GR <20.50 kg, area under curve [AUC] = 0.68) and men (GR <31.05 kg, AUC = 0.64). Near-perfect agreement was found between the derived ANZ cut points and SDOC cut points (CK 0.8-1.0). Sarcopenia prevalence ranged from 1.5% (EWGSOP2) to 37.2% (SDOC) in women and 1.0% (EWGSOP2) to 9.1% (SDOC) in men, with no agreement (CK <0.2) between EWGSOP2 and SDOC.

CONCLUSIONS

Grip strength is the primary discriminating characteristic for slow walking speed in ANZ women and men, consistent with findings from the SDOC. Sarcopenia Definitions and Outcomes Consortium and EWGSOP2 definitions showed no agreement suggesting these proposed definitions measure different characteristics and identify people with sarcopenia differently.

The Role of Different Weakness Cut-Points for Future Cognitive Impairment in Older Americans

OBJECTIVES

New absolute and normalized handgrip strength (HGS) cut-points may not yield similar predictive value for cognitive performance. We sought to determine the associations of (1) each absolute and normalized weakness cut-point, and (2) compounding weakness on future cognitive impairment in older Americans.

DESIGN

Longitudinal panel.

SETTING AND PARTICIPANTS

The analytic sample included 11,116 participants aged ≥65 years from the 2006 to 2018 waves of the Health and Retirement Study. Participants from the Health and Retirement Study completed detailed interviews that included physical measures and core interviews.

METHODS

The modified Telephone Interview of Cognitive Status assessed cognitive function and persons scoring <11 were classified as having a cognitive impairment. A handgrip dynamometer measured HGS. Men were considered weak if their HGS was <35.5 kg (absolute), <0.45 kg/kg (body mass normalized), or <1.05 kg (body mass index normalized), whereas women were classified as weak if their HGS was <20.0 kg, <0.337 kg/kg, or <0.79 kg. Compounding weakness included those below 1, 2, or all 3 cut-points. Generalized estimating equations quantified the associations.

RESULTS

Persons considered weak under the absolute cut-point had 1.62 (95% CI 1.34-1.96) greater odds for future cognitive impairment, but no significant associations were observed for those classified as weak under the body mass [odds ratio (OR) 1.12, CI 0.91-1.36] and body mass index normalized (OR 1.17, CI 0.95-1.43) cut-points. Older Americans below all 3 weakness cut-points had 1.47 (CI 1.15-1.88) greater odds for future cognitive impairment, but no significant associations were found for persons classified as weak under 1 (OR 1.08, CI 0.83-1.42) or 2 (OR 1.19, CI 0.91-1.55) cut-points.

CONCLUSIONS AND IMPLICATIONS

Our findings suggest that each weakness cut-point has differential prognostic value for future cognitive impairment, and aggregating weakness cut-points may improve their predictive utility. Consideration should be given to how weakness categories are uniquely linked to cognitive function.

Prevalence and Trends of Weakness Among Middle-Aged and Older Adults in the United States

ABSTRACT

McGrath, R, FitzSimmons, S, Andrew, S, Black, K, Bradley, A, Christensen, BK, Collins, K, Klawitter, L, Kieser, J, Langford, M, Orr, M, and Hackney, KJ. Prevalence and trends of weakness among middle-aged and older adults in the United States. J Strength Cond Res 37(12): 2484-2490, 2023-Muscle weakness, which is often determined with low handgrip strength (HGS), is associated with several adverse health conditions; however, the prevalence and trends of weakness in the United States is not well-understood. We sought to estimate the prevalence and trends of weakness in Americans aged at least 50 years. The total unweighted analytic sample included 22,895 Americans from the 2006-2016 waves of the Health and Retirement Study. Handgrip strength was measured with a handgrip dynamometer. Men with weakness were below at least one of the absolute or normalized (body mass, body mass index) cut points: <35.5 kg, <0.45 kg/kg, <1.05 kg/kg/m 2 . The presence of any weakness in women was also identified as being below one of the absolute or normalized HGS cut points: <20.0 kg, <0.34 kg/kg, or <0.79 kg/kg/m 2 . There was an increasing trend in the prevalence of any weakness over time ( p < 0.001). The prevalence of weakness was 45.1% (95% confidence interval [CI]: 44.0-46.0) in the 2006-2008 waves and 52.6% (CI: 51.5-53.7) in the 2014-2016 waves. Weakness prevalence was higher for older (≥65 years) Americans (64.2%; CI: 62.8-65.5) compared with middle-aged (50-64 years) Americans (42.2%; CI: 40.6-43.8) in the 2014-2016 waves. Moreover, the prevalence of weakness in the 2014-2016 waves was generally higher in women (54.5%; CI: 53.1-55.9) than in men (50.4%; CI: 48.7-52.0). Differences existed in weakness prevalence across races and ethnicities. The findings from our investigation suggest that the prevalence of weakness is overall pronounced and increasing in Americans. Efforts for mitigating and better operationalizing weakness will elevate in importance as our older American population grows.

Mortality, falls and slow walking speed are predicted by different muscle strength and physical performance measures in women and men

BACKGROUND

Different measures of muscle strength, physical performance and body size/composition are used in various sarcopenia definitions. This study investigated which baseline measures best predict incident mortality and falls, and prevalent slow walking speed in older women and men.

MATERIALS AND METHODS

Data for 899 women (mean age±standard deviation, 68.7 ± 4.3 years) and 497 men (69.4 ± 3.9 years) from the Dubbo Osteoporosis Epidemiology Study 2, comprising sixty variables for muscle strength (quadriceps strength), physical performance (walking speed, timed up and go (TUG) test, sit to stand (STS) test), body size (weight, height, body mass index) and body composition (lean mass, body fat) were included. Sex-stratified Classification and Regression Tree (CART) analyses calculated baseline variable accuracy for predicting incident mortality and falls, and prevalent slow walking speed (<0.8 m/s).

RESULTS

Over 14.5 years, 103/899 (11.5%) women and 96/497 (19.3%) men died, 345/899 (38.4%) women and 172/497 (34.6%) men had ≥1 fall, and 304/860 (35.3%) women and 172/461 (31.7%) had baseline slow walking speed (<0.8 m/s). CART models identified age and walking speed adjusted for height as the most important predictors for mortality in women, and quadriceps strength (with adjustments) as the most important predictor for mortality in men. In both sexes, STS (with adjustments) was the most important predictor for incident falls, and TUG test was the most important predictor for prevalent slow walking speed. Body composition measures were not important predictors for any outcome.

CONCLUSIONS

Muscle strength and physical performance variables and cut points predict falls and mortality differently in women and men, suggesting targeted sex-specific application of selected measures may improve outcome prediction in older adults.

Examining the role of different weakness categories for mobility and future falls in older Americans

BACKGROUND

Recently developed absolute and body size normalized handgrip strength (HGS) cut-points could be used individually and collectively to predict mobility problems and falls.

AIMS

We examined the associations of (1) each absolute and normalized weakness cut-point, (2) collective weakness categories, and (3) changes in weakness status on future falls in older Americans.

METHODS

The analytic sample included 11,675 participants from the 2006-2018 waves of the Health and Retirement Study. Falls were self-reported. Men were classified as weak if their HGS was < 35.5-kg (absolute), < 0.45 kg/kg (body mass normalized), or < 1.05 kg/kg/m2 (body mass index normalized). While, women were considered weak if their HGS was < 20.0-kg, < 0.337 kg/kg, or < 0.79 kg/kg/m2. Collective weakness categorized those below 1, 2, or all 3 cut-points. The collective weakness categories were also used to observe changes in weakness status over time.

RESULTS

Older Americans below each absolute and normalized cut-point had greater odds for future falls: 1.23 (95% confidence interval (CI): 1.15-1.32) for absolute weakness, 1.20 (CI 1.11-1.29) for body mass index normalized weakness, and 1.26 (CI 1.17-1.34) for body mass normalized weakness. Persons below 1, 2, or all 3 weakness cut-points had 1.17 (CI 1.07-1.27), 1.29 (CI 1.18-1.40), and 1.36 (CI 1.24-1.48) greater odds for future falls, respectively. Those in some changing weakness categories had greater odds for future falls: 1.26 (CI 1.08-1.48) for persistent and 1.31 (CI 1.11-1.55) for progressive.

DISCUSSION

Collectively using these weakness cut-points may improve their predictive value.

CONCLUSION

We recommend HGS be evaluated in mobility and fall risk assessments.

Sarcopenia Definition and Outcomes Consortium 2020 Definition: Association and Discriminatory Accuracy of Sarcopenia With Disability in the Canadian Longitudinal Study on Aging

BACKGROUND

Previous sarcopenia definitions have poor discriminatory accuracy for identifying people with/without relevant health outcomes, and poor agreement between methods of operationalizing sarcopenia criterion. The 2020 Sarcopenia Definitions and Outcomes Consortium (SDOC) definition recommends grip strength (absolute, or standardized to body mass index, total body fat, lean arm mass, or weight), and gait speed. The agreement between methods of operationalizing grip strength and discriminatory accuracy of the SDOC definition for health outcomes such as activities of daily living (ADL) disability is unknown.

METHODS

Cross-sectional analyses of 27 924 Canadian Longitudinal Study on Aging participants aged 45-85 at baseline (2012-2015) stratified by sex. The associations of the SDOC definitions with ADL disability were assessed using logistic regression. Area under the curve (AUC) analyses were conducted to assess discriminatory accuracy. Agreement between methods of operationalizing grip strength was measured using Cohen's kappa.

RESULTS

Sarcopenia was associated with 1.60 (1.42-1.80) to 5.80 (4.89-6.88) greater odds of ADL disability with AUC values between 0.60 and 0.81. Agreement between methods of operationalizing grip strength was between 0.10-0.80 for grip strength alone and 0.45-0.91 when combined with gait speed.

CONCLUSIONS

The SDOC-suggested criteria of grip strength and gait speed are significantly associated with ADL disability and have high discriminatory accuracy. However, the agreement between methods of operationalizing grip strength tended to be modest, and AUC, sensitivity, and specificity differed depending on the definition. We suggest a single measure of grip strength be considered and age-stratified cutoff values to improve AUC values.

Spot Urinary Creatinine Concentration in Patients with Chronic Heart Failure Identifies a Distinct Muscle-Wasting Phenotype with a Strikingly Different Risk of Mortality

BACKGROUND

There is a raising awareness that heart failure (HF) is a highly heterogeneous, multiorgan syndrome with an increasing global prevalence and still poor prognosis. The comorbidities of HF are one of the key reasons for presence of various phenotypes with different clinical profile and outcome. Heterogeneity of skeletal muscles (SMs) quantity and function may have an impact on patient's phenotype.

AIM

We intended to compare clinical characteristics of phenotypes defined by a combination of various SM mass taken as a fat-free compartment from DEXA scans and different levels of SUCR (Spot Urinary Creatinine). All-cause mortality with mortality predicted by MAGGIC in such phenotypes were compared.

METHODS

In 720 HF patients with reduced ejection fraction (age: 52.3 ± 10 years, female: 14%, NYHA: 2.7 ± 0.7, LVEF: 24.3 ± 7.3%), admitted to the hospital for heart transplantation candidacy assessment, morning SUCR along with body composition scanning (DEXA) was performed. All study participants were dichotomized twice, first by low or normal appendicular muscle mass index (ASMI) and second by SUCR (Spot Urinary Creatinine) < and ≥of 1.34 g/L. Four study groups (phenotypes) were created as combinations of lower or higher SUCR and low or normal ASMI.

RESULTS

Low ASMI was found in 242 (33.6%) patients, while the remaining 478 had normal muscle mass. In 446 patients (61.9%), SUCR was <1.34 g/L. During 3 years of follow-up, 223 (31.0%) patients died (all-cause). The phenotype of lower both ASMI and SUCR was associated with the highest mortality. The death rate in phenotype with both low ASMI and SUCR exceeded by 70% the risk estimated by MAGGIC. This difference was significant as judged by the 95% confidence interval for MAGGIC estimation. In Cox regression analysis adjusted for MAGGIC and parameters known to increase risk, the relative risk of patients with phenotype of low both ASMI and SUCR was elevated by 45-55% as compared to patients with all other phenotypes. The protective role of higher SUCR in patients with muscle wasting was, therefore, confirmed in Cox analysis.

CONCLUSIONS

Measurement of SUCR in HF patients can identify clinical phenotypes with skeletal muscle wasting but strikingly different risk of death that is actually not captured by MAGGIC score. The higher level of SUCR was associated with similar risk independently of presence of muscle wasting. As the analysis of SUCR is cheap and easy to perform, it should be further tested as a potentially useful biomarker, which may precisely phenotype HF patients independently of their skeletal muscle status.

Grip strength cut-points from the Swiss DO-HEALTH population

BACKGROUND

While grip strength (GS) is commonly assessed using a Dynamometer, the Martin Vigorimeter was proposed as an alternative method especially in older adults. However, its reference values for Swiss older adults are missing. We therefore aimed to derive sex- and age-specific GS cut-points for the dominant and non-dominant hand (DH; NDH) using the Martin Vigorimeter. Additionally, we aimed to identify clinically relevant weakness and assess convergent validity with key markers of physical function and sarcopenia in generally healthy Swiss older adults.

METHODS

This cross-sectional analysis includes baseline data from Swiss participants enrolled in DO-HEALTH, a 3-year randomized controlled trial in community-dwelling adults age 70 + . For both DH and NDH, 4 different definitions of weakness to derive GS cut-points by sex and age category (≤ 75 vs. > 75 years) were used: i) GS below the median of the 1st quintile, ii) GS below the upper limit of the 1st quintile, iii) GS below 2-standard deviation (SD) of the sex- and age-specific mean in DO-HEALTH Swiss healthy agers (i.e. individuals without major chronic diseases, disabilities, cognitive impairment or mental health issues) and iv) GS below 2.5-SD of the sex- and age-specific mean in DO-HEALTH Swiss healthy agers. To assess the proposed cut-points' convergent validity, we assessed their association with gait speed, time to complete the 5 Times Sit-To-Stand (5TSTS) test, and present sarcopenia.

RESULTS

In total, 976 participants had available GS at the DH (mean age 75.2, 62% women). According to the 4 weakness definitions, GS cut-points at the DH ranged from 29-42 and 25-39 kPa in younger and older women respectively, and from 51-69 and 31-50 kPa in younger and older men respectively. Overall, weakness prevalence ranged from 2.0% to 19.3%. Definitions of weakness using the median and the upper limit of the 1st GS quintile were most consistently associated with markers of physical performance. Weak participants were more likely to have lower gait speed, longer time to complete the 5TSTS, and sarcopenia, compared to participants without weakness.

CONCLUSIONS

In generally healthy Swiss older adults, weakness defined by the median or the upper limit of the 1st GS quintile may serve as reference to identify clinically relevant weakness. Additional research is needed in less healthy populations in order to derive representative population-based cut-points.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT01745263.

Optimizing the Design of Clinical Trials to Evaluate the Efficacy of Function-Promoting Therapies

BACKGROUND

Several candidate molecules that may have application in treating physical limitations associated with aging and chronic diseases are in development. Challenges in the framing of indications, eligibility criteria, and endpoints and the lack of regulatory guidance have hindered the development of function-promoting therapies.

METHODS

Experts from academia, pharmaceutical industry, National Institutes of Health (NIH), and Food and Drug Administration (FDA) discussed optimization of trial design including the framing of indications, eligibility criteria, and endpoints.

RESULTS

Mobility disability associated with aging and chronic diseases is an attractive indication because it is recognized by geriatricians as a common condition associated with adverse outcomes, and it can be ascertained reliably. Other conditions associated with functional limitation in older adults include hospitalization for acute illnesses, cancer cachexia, and fall injuries. Efforts are underway to harmonize definitions of sarcopenia and frailty. Eligibility criteria should reconcile the goals of selecting participants with the condition and ensuring generalizability and ease of recruitment. An accurate measure of muscle mass (eg, D3 creatine dilution) could be a good biomarker in early-phase trials. Performance-based and patient-reported measures of physical function are needed to demonstrate whether treatment improves how a person lives, functions, or feels. Multicomponent functional training that integrates training in balance, stability, strength, and functional tasks with cognitive and behavioral strategies may be needed to translate drug-induced muscle mass gains into functional improvements.

CONCLUSIONS

Collaborations among academic investigators, NIH, FDA, pharmaceutical industry, patients, and professional societies are needed to conduct well-designed trials of function-promoting pharmacological agents with and without multicomponent functional training.

Combinations of Sarcopenia Diagnostic Criteria by Asian Working Group of Sarcopenia (AWGS) 2019 Guideline and Incident Adverse Health Outcomes in Community-Dwelling Older Adults

OBJECTIVES

This study aimed to investigate the association between combinations of sarcopenia criteria by the Asian Working Group of Sarcopenia (AWGS) 2019 guideline and incident adverse health outcomes.

DESIGN

Longitudinal analyses of a cohort study.

SETTING AND PARTICIPANTS

We conducted prospective 2-year follow-up analyses (N = 1959) among community-dwelling older adults enrolled in the nationwide Korean Frailty and Aging Cohort Study (KFACS).

METHODS

From the KFACS, 1959 older adults (52.8% women; mean age = 75.9 ± 3.9 years) who underwent assessments for appendicular skeletal mass using dual-energy X-ray absorptiometry, handgrip strength, usual gait speed, 5-times sit-to-stand test, and Short Physical Performance Battery (SPPB) at baseline were included. Participants with each adverse health outcome [mobility disability, falls, and instrumental activities of daily living (IADL) disabilities] at baseline were excluded for each corresponding analysis. Multivariable logistic regression was performed to examine whether sarcopenia defined by different diagnostic criteria was associated with incident adverse health outcomes after 2 years.

RESULTS

A total of 444 participants (22.7%) were diagnosed with sarcopenia as defined by AWGS 2019. In the multivariable analysis, sarcopenia defined as both low muscle mass and low physical performance increased the risk of mobility disability (OR 2.14, 95% CI 1.35-3.38) and falls (1.74, 95% CI 1.21-2.49). Only the criterion defined as both low muscle mass and physical performance using the SPPB increased the risk of falls with fracture (2.53, 95% CI 1.01-6.35) and IADL disabilities (2.77, 95% CI 1.21-6.33). However, sarcopenia defined as both low muscle mass and low hand grip strength showed no associations with the incidence of any of the adverse health outcomes.

CONCLUSIONS AND IMPLICATIONS

Our study suggests that the predictive value of adverse health outcomes for community-dwelling older adults is better when diagnosed with sarcopenia based on low muscle mass and physical performance. Furthermore, using the SPPB as a diagnostic tool for low physical performance may improve the predictive validity for falls with fracture and IADL disability. Our findings may be helpful for the early detection of individuals with sarcopenia who have a higher risk of adverse health outcomes.

Associations of height, weight, and body mass index with handgrip strength: A Bayesian comparison in older adults

BACKGROUND & AIMS

Handgrip strength is commonly normalized or stratified by body size to define subgroup-specific cut-points and reference limits values. However, it remains unclear which anthropometric variable is most strongly associated with handgrip strength. We aimed to, in older adults with no self-reported mobility limitations, determine whether height, weight, and body mass index (BMI) were meaningfully associated with handgrip strength.

METHODS

This cross-sectional study included community-dwelling ambulant participants, and we identified 775 older adults who reported no difficulty walking 100 m, climbing stairs, and rising from the chair. Handgrip strength was measured with a digital dynamometer. Bayesian linear regression was used to estimate the probabilities that the positive associations of height, weight, and BMI with handgrip strength exceeded 0 kg (the null value) and 2.5 kg (the clinically meaningful threshold value).

RESULTS

Mean handgrip strength was 22.1 kg (SD, 4) for women and 32.9 kg (SD, 6) for men. Body height, weight, and BMI had >99.9% probabilities of a positive association with handgrip strength; however, the associations of per interquartile increase in body weight and BMI with handgrip strength had low probabilities (<5%) of exceeding the clinically meaningful threshold of 2.5 kg. In contrast, body height had the highest probability (99.6%) of a clinically meaningful association with handgrip strength: adjusting for age and gender, handgrip strength was 3.2 kg (95% CrI, 2.7 to 3.8) greater in older adults 1.61 m tall than in older adults 1.51 m tall.

CONCLUSIONS

In a large sample of mobile-intact older adults, handgrip strength differed meaningfully by body height. Although requiring validation, our findings suggest that future efforts should be directed at normalizing handgrip strength by body height to better define subgroup-specific handgrip weakness. A web-based application (https://sghpt.shinyapps.io/ippts/) was created to allow interactive exploration of predicted values and reference limits of age-, gender-, and height-subgroups.

Sarcopenia Definition Outcome Consortium - defined Weakness and Risk of Falls: The National Health and Aging Trends Survey

AIM

The prevalence of obesity continues to rise, as does that of weakness. However, it is unclear how this impacts the risk of falling. We aimed to ascertain the risk of falls using new definitions of clinically defined weakness.

METHODS

We applied clinically defined weakness definitions to the National Health and Aging Trends Survey using the Sarcopenia Definitions Outcomes Consortium cutpoints. Three exposure variables were created: grip-strength-defined weakness and body mass index [GS/BMI]-defined obesity; weakness and obesity, weakness and waist circumference-derived obesity (GS/WC); and weakness defined by a ratio of GS÷BMI. Proportional hazards modeled incident falls as a function of weakness with/without obesity (hazard ratio [HR] [95% confidence intervals]).

RESULTS

Of 4906 respondents aged ≥ 65 years (54.5% female), the mean ± SD grip strength, BMI, and WC were 26.7 ± 10.6 kg, 27.4 ± 5.4 kg/m2 , and 99.5 ± 16.3 cm, respectively. Using the neither weakness/obesity as the referent, weakness was associated with incident falls across all definitions (GS/BMI: HR 1.19 [1.07, 1.33]; GS/WC: HR 1.39 [1.19, 1.62]; GS ÷ BMI: HR 1.16 [1.05, 1.28]). Weakness with obesity was associated with falls using GS/WC (HR 1.28 [1.11, 1.48]). Obesity status was associated with falls in both the BMI and the WC definition (1.17 [1.02-1.35], 1.16 [1.05-1.28]).

CONCLUSION

Our findings further evaluate the definitions of clinically defined weakness with and without obesity in older adults. As falls are an important patient outcome, establishing this relationship is critical for both clinicians and researchers. Future study should identify high-risk individuals in order to direct specific interventions to them. Geriatr Gerontol Int 2023; 23: 213-220.

Hand Grip Strength Relative to Waist Circumference as a Means to Identify Men and Women Possessing Intact Mobility in a Cohort of Older Adults with Type 2 Diabetes

Possessing intact mobility in older adults assures their continued independence. The early identification of reduced mobility in older adults with type 2 diabetes (T2DM) is paramount for preventing their future physical deterioration. Hand grip strength (HGS), relative to body size, is associated with mobility in older T2DM patients. This study aims to identify an HGS index that best identifies mobilityintact older T2DM patients, along with its optimal cut-off point. The baseline data are from a cohort of 122 older T2DM patients (59% women) (mean age of 70.2 ± 4.4 years). Three mobility tests encompassing three main mobility domains were measured, including usual gait speed (UGS), timed up and go (TUG), and a two-minute walk test (2MWT). Passing scores were defined as those either above the established cut-off points or above the 25th percentile of population norms. Passing all three tests was considered as possessing intact mobility. Receiver operating characteristic (ROC) curves of the most relevant HGS indices were constructed to determine the area under the curve (AUC) that best identifies patients with intact mobility. In a sample of 122 older adults with T2DM, 63.9% of women and 60% of men were found to possess intact mobility. HGS relative to waist circumference (WC) was found to have the strongest association with intact mobility, presenting the highest AUC in both men (0.78) and women (0.72) for discriminating mobility status, with an optimal cut-off of 0.355 (kg/cm) and 0.245 (kg/cm) in men and women, respectively. HGS relative to WC best differentiated between mobility-intact older adults with T2DM and those with mobility limitations, especially in men. Using HGS/WC as a simple and safe screening mode for mobility in a clinical setting could potentially identify older patients with T2DM that require therapeutic interventions.

Associations between biomarkers of cellular senescence and physical function in humans: observations from the lifestyle interventions for elders (LIFE) study

Cellular senescence is a plausible mediator of age-associated declines in physical performance. To test this premise, we examined cross-sectional associations between circulating components of the senescence-associated secretory phenotype (SASP) and measures of physical function and muscle strength in 1377 older adults. We showed significant associations between multiple SASP proteins and the short physical performance battery (SPPB), its subcomponents (gait speed, balance, chair rise time), and 400-m walk time. Activin A, ICAM1, MMP7, VEGFA, and eotaxin showed strong associations based on gradient boost machine learning (GBM), and, when combined with other proteins, effectively identified participants at the greatest risk for mobility disability (SPPB score [Formula: see text] 7). Senescence biomarkers were also associated with lower grip strength, and GBM identified PARC, ADAMTS13, and RANTES as top candidates in females, and MMP2, SOST, and MCP1 in males. These findings highlight an association between senescence biomarkers and physical performance in older adults. ClinicalTrials.gov Identifier: NCT01072500.

Public Health Need, Molecular Targets, and Opportunities for the Accelerated Development of Function-Promoting Therapies: Proceedings of a National Institute on Aging Workshop

Background

People ≥ 65 years are expected to live a substantial portion of their remaining lives with a limiting physical condition and the numbers of affected individuals will increase substantially due to the growth of the population of older adults worldwide. The age-related loss of muscle mass, strength, and function is associated with an increased risk of physical disabilities, falls, loss of independence, metabolic disorders, and mortality. The development of function-promoting therapies to prevent and treat age-related skeletal muscle functional limitations is a pressing public health problem.

Methods

On March 20–22, 2022, the National Institute on Aging (NIA) held a workshop entitled “Development of Function-Promoting Therapies: Public Health Need, Molecular Targets, and Drug Development.”

Results

The workshop covered a variety of topics including advances in muscle biology, novel candidate molecules, findings from randomized trials, and challenges in the design of clinical trials and regulatory approval of function-promoting therapies. Leading academic investigators, representatives from the National Institutes of Health (NIH) and the U.S. Food and Drug Administration (FDA), professional societies, pharmaceutical industry, and patient advocacy organizations shared research findings and identified research gaps and strategies to advance the development of function-promoting therapies. A diverse audience of 397 national and international professionals attended the conference.

Conclusions

Function-promoting therapies to prevent and treat physical disabilities associated with aging and chronic diseases are a public health imperative. Appropriately powered, well-designed clinical trials and synergistic collaboration among academic experts, patients and stakeholders, the NIH and the FDA, and the pharmaceutical industry are needed to accelerate the development of function-promoting therapies.

Association of muscle strength and body mass index with risk factors for metabolic syndrome and its prevalence in Korean adult women

Background

The aim of this study was to investigate the effects of muscle strength and BMI (body Mass Index) on Metabolic syndrome (MetS) risk factors and prevalence in Korean adult women, using data from the Korea National Health and Nutrition Examination Survey.

Methods

A total of 3189 Korean adults women participated in the cross-sectional study. Participants were measured BMI, MetS risk factors including waist-circumference (WC), fasting glucose (FG), triglyceride (TG), high density lipoprotein cholesterol (HDL-C), and handgrip strength as muscle strength.

Results

As a result ‘high BMI & Low muscle strength’, ‘low BMI & low muscle strength’, and ‘high BMI & high muscle strength’ groups had a significantly higher prevalence of Mets [OR (Odd ratio): 1.49, 95% CI (confidence interval): 1.01 2.20; OR: 5.77, 95% CI: 4.32 7.17; OR: 10.46, 95% CI: 8.05 13.59] than ‘low BMI & high muscle strength’ group; and after adjusting smoking, menstruation status, and drinking rate, the OR were 1.07 (95% CI: 0.71–1.61), 4.89 (95% CI: 3.60–6.55), and 7.38 (95% CI: 5.63–9.68), respectively.

Conclusions

These findings indicated that increasing muscle strength and lowering BMI through regular physical activity and exercise are effective methods to reduce the prevalence of risk factors for Mets.

Muscle Weakness and Walking Slowness for the Identification of Sarcopenia in the Older Adults from Northern Brazil: A Cross-Sectional Study

Background: This study aimed to analyze the prevalence of sarcopenia in elderly people from Northern Brazil according to muscle weakness or walking slowness. Methods: The sample consisted of 312 elderly people (72.6 ± 7.8 years). For walking slowness, a gait speed ≤ 0.8 m/s was used as a cut-off value, and for muscle weakness the following handgrip strength criteria were used for men and women, respectively: CI: <27.0/16.0 kg; CII: <35.5/20.0 kg; CIII: grip strength corrected for body mass index (BMI) < 1.05/0.79; CIV: grip strength corrected for total fat mass: <1.66/0.65; CV: grip strength corrected for body mass: <0.45/0.34. Results: Walking speed was reduced in 27.0% of women and 15.2% of men (p < 0.05). According to grip strength criteria, 28.5% of women and 30.4% of men (CI), 58.0% of women and 75.0% of men (CII), 66.0% of women and 39.3% of men (CIII), 28.8% of women and 19.6% of men (CIV), and 56.5% of women and 50.0% of men (CV) were identified as having sarcopenia. Conclusions: Walking slowness is more prevalent in women and muscle weakness is more prevalent in men in Northern Brazil. Walking slowness proved to be more concordant with muscle weakness in both sexes when the CI for handgrip strength was adopted.

Are Machine Learning Models on Wrist Accelerometry Robust against Differences in Physical Performance among Older Adults?

Sufficient physical activity (PA) reduces the risk of a myriad of diseases and preserves physical capabilities in later life. While there have been significant achievements in mapping accelerations to real-life movements using machine learning (ML), errors continue to be common, particularly for wrist-worn devices. It remains unknown whether ML models are robust for estimating age-related loss of physical function. In this study, we evaluated the performance of ML models (XGBoost and LASSO) to estimate the hallmark measures of PA in low physical performance (LPP) and high physical performance (HPP) groups. Our models were built to recognize PA types and intensities, identify each individual activity, and estimate energy expenditure (EE) using wrist-worn accelerometer data (33 activities per participant) from a large sample of participants (n = 247, 57% females, aged 60+ years). Results indicated that the ML models were accurate in recognizing PA by type and intensity while also estimating EE accurately. However, the models built to recognize individual activities were less robust. Across all tasks, XGBoost outperformed LASSO. XGBoost obtained F1-Scores for sedentary (0.932 ± 0.005), locomotion (0.946 ± 0.003), lifestyle (0.927 ± 0.006), and strength flexibility exercise (0.915 ± 0.017) activity type recognition tasks. The F1-Scores for recognizing low, light, and moderate activity intensity were (0.932 ± 0.005), (0.840 ± 0.004), and (0.869 ± 0.005), respectively. The root mean square error for EE estimation was 0.836 ± 0.059 METs. There was no evidence showing that splitting the participants into the LPP and HPP groups improved the models’ performance on estimating the hallmark measures of physical activities. In conclusion, using features derived from wrist-worn accelerometer data, machine learning models can accurately recognize PA types and intensities and estimate EE for older adults with high and low physical function.

Adjusting Grip Strength to Body Size: Analyses From 6 Countries

OBJECTIVES

Absolute handgrip strength and adjusted by body mass index are useful to identify geriatric syndromes. However, these values are not accurate for older adults with extreme body size because of the nonlinear relationship between strength, height, and body mass. The purpose of this study was to determine cut-off points for geriatric syndromes of older adults using allometric coefficients to normalize grip strength by body size.

DESIGN

Cross-sectional study.

SETTING AND PARTICIPANTS

Data from 13,235 older adults of Study on Global Aging and Adult Health conducted in 6 low- and middle-income countries were analyzed.

METHODS

Country- and sex-specific allometric exponents for body-size variables (mass and height) were computed with log-linear models. Partial correlation verified whether allometric normalization removed the effect of body size on grip strength. Cut-off points were established (<20th percentile) for low allometrically adjusted grip strength.

RESULTS

Allometric exponents for normalization of grip strength were provided for body-size variables, ranging from 0.19 to 2.45. Allometric normalization removed the effect of body size on grip strength (r < 0.30). Overall, frequencies of low muscle strength were overestimated with international criteria (absolute grip strength) compared with the cut-off points proposed in this study.

CONCLUSIONS AND IMPLICATIONS

The proposed allometric exponents normalized grip strength according to body-size variables. These exponents improved the accuracy in identifying geriatric syndromes in older adults with extreme body size. The variability between strength reveals the need for developing specific cut-off points for low- and middle-income countries. New cut-off points of low normalized grip strength with automatized applicability were proposed for health care providers use in clinical practice.

How Should Adult Handgrip Strength Be Normalized? Allometry Reveals New Insights and Associated Reference Curves

INTRODUCTION

Handgrip strength (HGS) is an important indicator of health. Because HGS is strongly associated with body size, most investigators normalize HGS for some measure of body size as a more sensitive indicator of strength within a population. We aimed to 1) identify the optimal body size dimension to remove (normalize) HGS for differences in body size among adults and 2) generate norm-referenced centiles for HGS using the identified body size dimension.

METHODS

Data were from the National Health and Nutrition Examination Survey, a representative sample of the US noninstitutionalized civilian population. Exclusions resulted in a final sample of 8690 adults 20 yr and older. HGS was measured using handheld dynamometry. Body size dimensions included body mass, height, and waist circumference. The most appropriate dimension(s) associated with HGS is identified using allometry. We fitted centile curves for normalized HGS using the generalized additive model for location, scale, and shape.

RESULTS

Findings suggest that neither body mass nor body mass index is appropriate to normalize HGS. Incorporating all three body size dimensions of body mass, height, and waist circumference, or the reduced subsets of body mass and height, or height alone, suggests that the most appropriate normalizing (body size) dimension associated with HGS should be a cross-sectional or surface area measure of an individual's body size (i.e., L2, where L is a linear dimension of body size). Given that height was also identified as the signally best body size dimension associated with HGS, we recommend HGS be normalized by height2 (i.e., HGS/HT2). Centile curves for HGS/HT2 by age group and gender were therefore provided.

CONCLUSIONS

Scaling adult HGS by height2 may help normalize strength for population-based research.

Comparison between Original and Reviewed Consensus of European Working Group on Sarcopenia in Older People: A Probabilistic Cross-Sectional Survey among Community-Dwelling Older People

INTRODUCTION

The European Working Group on Sarcopenia in Older People (EWGSOP) published a consensus on sarcopenia in 2010 and updated it in 2019 (EWGSOP2) which included the use of specific cut-off points. The aim was to assess how much prevalence of sarcopenia differed between EWGSOP2 and EWGSOP, as well as the use of specific cut-off points to assess differences in presarcopenia versus probable sarcopenia.

METHODS

Observational, transversal, and comparative study (n = 1,283 older adults; 57% women). Anthropometrics and handgrip strength were measured, and appendicular skeletal muscle mass equation was defined. Conceptual and methodological definitions of EWGSOP and EWGSOP2 consensus were applied to calculate prevalence of presarcopenia, probable sarcopenia, and sarcopenia.

RESULTS

Using cut-off points recommended for European population, prevalence of sarcopenia with EWGSOP2 was lower (-6.6%; p < 0.001) than EWGSOP. The prevalence of probable sarcopenia (EWGSOP2) was higher (+7.8%; p < 0.001) than EWGSOP presarcopenia. The agreement between EGWGSOP and EWGSOP2 was moderated (K = 0.45; IC = 0.40-0.51). Using specific-population cut-off points for muscle strength and appendicular muscle mass, the prevalence of probable sarcopenia with EWGSOP2 was higher (46.5%; p < 0.001) than EWGSOP (1.8%). The agreement between EGWGSOP and EWGSOP2 was moderated (K = 0.48; IC = 0.42-0.52).

CONCLUSION

The new EWGSOP2 consensus underestimates the prevalence of sarcopenia, compared with EWGSOP using conventional cut-off points. The prevalence of presarcopenia with EWGSOP (low muscle mass) was lower than probable sarcopenia (low muscle strength) with the new EWGSOP2. In both cases, agreements between EWGSOP2 and EWGSOP were moderated. Discrepancies between the original and new consensus have implications on the primary health setting for identifying old and new cases for prevention and treatment.

Grip strength performance from 9431 participants of the GenoFit study: normative data and associated factors

Weak grip strength is a strong predictor of multiple adverse health outcomes and an integral diagnostic component of sarcopenia. However, the limited availability of normative data for certain populations impedes the interpretation of grip performance across adulthood. This study aimed to establish normative data and low grip strength thresholds in a large adult population, and to examine associations between grip strength and clinically relevant health variables. A total of 9431 adults aged between 18 and 92 years participated in this study (mean age: 44.8 ± 13.4 years; 57% females). Grip strength, body composition, and cardiorespiratory (CR) fitness were assessed using hand dynamometry, dual-energy x-ray absorptiometry and physical work capacity tests, respectively. Low grip strength was established according to criteria of the European Working Group on Sarcopenia in Older People. Normative data and t-scores, stratified by sex and age groups, are presented. Grip performance was associated with lean mass, skeletal muscle index (SMI), fat mass, CR fitness, bone mineral density (BMD), android/gynoid ratio, disease prevalence and physical activity levels (all p < 0.001) after controlling for multiple potential confounders. Individuals with weak grip strength had lower lean mass, SMI, CR fitness (all p < 0.001) and BMD (p = 0.001), and higher disease prevalence (p < 0.001), compared to healthy controls, although sex-specific differences were observed. Grip strength has practical screening utility across a range of health domains. The normative data and grip strength thresholds established in this study can guide the clinical interpretation of grip performance and facilitate timely therapeutic strategies targeting sarcopenia.

Plasma C-Terminal Agrin Fragment as an Early Biomarker for Sarcopenia: Results from the Genofit Study

Barriers associated with direct muscle quantification have prevented a consistent implementation of therapeutic measures for sarcopenia. Recently, the relevance of circulating C-terminal agrin fragment (CAF) as an accessible screening method alternative for sarcopenia has gained credence. Accordingly, this study aimed to verify the pertinence of plasma CAF as a biomarker for sarcopenia. Three hundred healthy adults aged between 50 and 83 years took part in this study. Sarcopenia was diagnosed according to the European Working Group on Sarcopenia in Older People criteria. Body composition was assessed using dual-energy x-ray absorptiometry, while muscle strength was examined using hand dynamometry. Plasma CAF concentrations were determined using a commercially available ELISA kit. CAF concentrations were significantly associated with appendicular lean mass (ALM), but not grip strength (p = .028, p = .575, respectively). Plasma CAF concentrations were significantly elevated in sarcopenic individuals compared to nonsarcopenic (p < .001). Overall, individuals with low grip strength or low ALM displayed significantly higher CAF levels compared to healthy controls, after adjusting for age and body mass index (p = .027, p = .003, respectively). In males, those with low grip strength or low ALM had significantly elevated CAF levels (p = .039, p = .027, respectively), while in females, only those with low ALM had significantly raised CAF concentrations, compared to healthy controls (p = .035). Our findings illuminate the potential relevance of CAF as an accessible biomarker for skeletal muscle health. CAF determination may enhance clinical practice by facilitating more widespread treatment strategies for sarcopenia. Nevertheless, future research is needed to confirm the diagnostic pertinence of CAF concentrations in screening for sarcopenia.

Performance of the EWGSOP2 Cut-Points of Low Grip Strength for Identifying Sarcopenia and Frailty Phenotype: A Cross-Sectional Study in Older Inpatients

Background: The European Working Group on Sarcopenia has recently proposed revised cut-off values for the definition of low grip strength (EWGSOP2). We therefore compared performance of the EWGSOP2 cut-off definition of low grip strength with other internationally used cut-off points in a sample of older patients. Methods: We analyzed geriatric assessment data in a cross-sectional sample of 98 older patients admitted to a post-acute care hospital. First, we compared prevalence of sarcopenia and frailty phenotype in our sample using low grip strength cut-points from the EWGSOP2 and seven other internationally used consensus statements. Second, we calculated correlations between low grip strength and two independent surrogate outcomes (i.e., gait speed, and the clinical frailty scale) for the EWGSOP2 and the other seven cut-point definitions. Results: Prevalence of sarcopenia based on the EWGSOP2 grip strength cut-off values was significantly lower (10.2%) than five of the seven other cut-point definitions (e.g., 19.4% based on Sarcopenia Definitions and Outcomes Consortium (SDOC) criteria). Similarly, frailty phenotype prevalence was significantly lower based on EWGSOP2 cut-points (57.1%) as compared to SDOC (70.4%). The correlation coefficient of gait speed with low grip strength based on EWGSOP2 cut-points was lower (0.145) as compared to other criteria (e.g., SDOC 0.240). Conclusions: Sarcopenia and frailty phenotype were identified considerably less using the EWGSOP2 cut-points for low grip strength, potentially underestimating prevalence of sarcopenia and frailty phenotype in post-acute hospital patients.

Motor function is the primary driver of the associations of sarcopenia and physical frailty with adverse health outcomes in community-dwelling older adults

Background

This study tested the hypothesis that sarcopenia and its constituent components, reduced lean muscle mass and impaired motor function, are associated with reduced survival and increased risk of incident disabilities.

Methods

1466 community-dwelling older adults underwent assessment of muscle mass with bioelectrical impedance analysis (BIA), grip strength, gait speed and other components of physical frailty and annual self-report assessments of disability. We used Cox proportional hazards models that controlled for age, sex, race, education and height to examine the associations of a continuous sarcopenia metric with the hazard of death and incident disabilities.

Results

Mean baseline age was about 80 years old and follow-up was 5.5 years. In a proportional hazards model controlling for age, sex, race, education and baseline sarcopenia, each 1-SD higher score on a continuous sarcopenia scale was associated with lower hazards of death (HR 0.70, 95%CI [0.62, 0.78]), incident IADL (HR 0.80,95%CI [0.70, 0.93]), incident ADL disability (HR 0.80 95%CI [71, 91]) and incident mobility disability (HR 0.81, 95%CI [0.70, 0.93]). Further analyses suggest that grip strength and gait speed rather than muscle mass drive the associations with all four adverse health outcomes. Similar findings were observed when controlling for additional measures used to assess physical frailty including BMI, fatigue and physical activity.

Conclusions

Motor function is the primary driver of the associations of sarcopenia and physical frailty with diverse adverse health outcomes. Further work is needed to identify other facets of muscle structure and motor function which together can identify adults at risk for specific adverse health outcomes.

Quantifying Muscle Mass by Adjusting for Body Mass Index Is the Best for Discriminating Low Strength and Function in Japanese Older Outpatients

OBJECTIVES

To investigate the association of three muscle mass adjustment methods with low muscle strength (MS) and low physical function (PF) defined by the Asian Working Group for Sarcopenia (AWGS) 2019 criteria.

DESIGN

Cross-sectional study.

SETTING

Clinical setting.

PARTICIPANTS

We included 361 outpatients (77.9 ± 5.9 years) without scheduled orthopedic surgery or activities of daily living disability.

MEASUREMENTS

Appendicular skeletal muscle mass (ASM) was measured by dual-energy X-ray absorptiometry, then divided by height-square (ht2), body weight, and body mass index (BMI) to calculate the ASM indexes. We assessed grip strength, gait speed, short physical performance battery, and five-time chair stand test. Low MS and low PF were defined by the AWGS2019 criteria. To compare the association of three muscle mass adjustments with low MS and low PF, multiple logistic regression analysis was performed, adjusted for age in each sex.

RESULTS

Participants with low MS was 31.5%, low PF was 50.1%. After adjustment, only ASM/BMI was significantly associated with all independent variables, such as low MS, low PF, and either of these, with the odds ratios of 2.09, 2.08, and 2.50 for males; and 1.87, 2.43, and 2.71 for females, respectively.

CONCLUSION

Our findings suggest that ASM/BMI is best associated with low MS and low PF in older Japanese outpatients. Longitudinal outcome studies are needed to confirm our findings.

Association between Sarcopenia and Fall Risk According to the Muscle Mass Adjustment Method in Japanese Older Outpatients

We investigated whether the association between sarcopenia and fall risk (FR) differs according to the muscle mass adjustment method in 357 outpatients who were not disabled in the activities of daily living or indicated for orthopedic surgery. Sarcopenia was diagnosed by the Asian Working Group for Sarcopenia (AWGS) 2019 criteria, using adjusting methods of muscle mass by height squared (ht2), body mass index (BMI), or any of these (i.e., ht2-adjusted Sarc", "BMI-adjusted Sarc", or "ht2 and/or BMI-adjusted Sarc, respectively). FR was defined by FR index ≥10. There were 111, 105, and 157 participants with ht2-adjusted, BMI-adjusted, and ht2 and/or BMI-adjusted Sarc, respectively. After multivariable adjustment, ht2 and/or BMI-adjusted Sarc was the most closely associated with FR [odds ratio and 95% confidence interval: 2.94, 1.75-4.93]. Our data suggest that the sarcopenia definition using low ASM/ht2 and/or ASM/BMI muscle mass might better predict adverse outcomes in older patients.

Sarcopenia Definition & Outcomes Consortium Defined Low Grip Strength in Two Cross-Sectional, Population-Based Cohorts

BACKGROUND/OBJECTIVES

The extent to which the prevalence of muscle weakness in the US population varies by different putative grip strength constructs developed by the Sarcopenia Definitions and Outcomes Consortium (SDOC) has not been described.

DESIGN

Cross-sectional analysis.

SETTING

Two nationally representative cohorts-2010 and 2012 waves of the Health and Retirement Survey and round 1 (2011) of the National Health and Aging Trends Survey.

PARTICIPANTS

Adults aged 65 years and older (n = 12,984) were included in these analyses.

MEASUREMENTS

We analyzed three constructs of muscle weakness developed by the SDOC, and found to be associated with mobility disability for men and women, respectively: absolute grip strength (<35.5 kg and 20 kg); grip strength standardized to body mass index (<1.05 kg/kg/m² and 0.79 kg/kg/m²); and grip strength standardized to weight (<0.45 kg/kg and 0.337 kg/kg). We estimated the prevalence of muscle weakness defined by each of these constructs in the overall older US population, and by age, sex, race, and ethnicity. We also estimated the sensitivity and specificity of each of the grip strength constructs to discriminate slowness (gait speed <0.8 m/s) in these samples.

RESULTS

The prevalence of muscle weakness ranged from 23% to 61% for men and from 30% to 66% for women, depending on the construct used. There was substantial variation in the prevalence of muscle weakness by race and ethnicity. The sensitivity and specificity of these measures for discriminating slowness varied widely, ranging from 0.30 to 0.92 (sensitivity) and from 0.17 to 0.88 (specificity).

CONCLUSIONS

The prevalence of muscle weakness, defined by the putative SDOC grip strength constructs, depends on the construct of weakness used. J Am Geriatr Soc 68:1438-1444, 2020.

Application of Cut-Points for Low Muscle Strength and Lean Mass in Mobility-Limited Older Adults

BACKGROUND

The Sarcopenia Definitions and Outcomes Consortium (SDOC) is a collaborative initiative seeking to develop and evaluate cut-points for low muscle strength and lean mass that predict an increased risk for slowness (usual walking speed <.8 m/s) among older adults.

OBJECTIVES

The goal of the present study was to provide clinicians and researchers with an understanding of the diagnostic implications of using SDOC variables and cut-points in mobility-limited older adults. Using data from older individuals with specific conditions that render them at increased risk for mobility limitation, we evaluated the performance characteristics (ie, sensitivity and specificity) of five putative sarcopenia parameters and then compared these values with previously recommended diagnostic criteria for sarcopenia.

DESIGN

Retrospective analysis of six randomized controlled trials enriched in persons at risk for mobility limitation.

SETTING

National and international geriatric clinical research centers.

PARTICIPANTS

A total of 925 mobility-limited older adults (≥55 years of age; 58% women) were included in the analysis.

MEASUREMENTS

The prevalence of low muscle strength and lean mass were assessed using five candidate metrics discriminative of slowness. Analyses of sensitivity and specificity were used to compare muscle weakness criteria with published diagnostics for sarcopenia.

RESULTS

Odds ratios (ORs) supported maximal grip strength (Grip max <35.5 and 20.0 in men and women, respectively) as the most discriminative of slowness in both men and women (OR = 3.66 and 3.53, respectively). More men (58%) than women (30%) fell below sex-specific maximal grip cut-points. When applying previously recommended sarcopenia component definitions in our population, we found that fewer individuals met those criteria (range = 6%-32%).

CONCLUSION

A greater number of individuals fall below SDOC Grip max cut-points compared with previous recommendations. Clinicians and researchers working with older adults may consider these thresholds as an inclusive means to identify candidates for low-risk lifestyle promyogenic and function-promoting therapies. J Am Geriatr Soc 68:1445-1453, 2020.

Putative Cut-Points in Sarcopenia Components and Incident Adverse Health Outcomes: An SDOC Analysis

OBJECTIVES

Analyses performed by the Sarcopenia Definitions and Outcomes Consortium (SDOC) identified cut-points in several metrics of grip strength for consideration in a definition of sarcopenia. We describe the associations between the SDOC-identified metrics of low grip strength (absolute or standardized to body size/composition); low dual-energy x-ray absorptiometry (DXA) lean mass as previously defined in the literature (appendicular lean mass [ALM]/ht2 ); and slowness (walking speed <.8 m/s) with subsequent adverse outcomes (falls, hip fractures, mobility limitation, and mortality).

DESIGN

Individual-level, sex-stratified pooled analysis. We calculated odds ratios (ORs) or hazard ratios (HRs) for incident falls, mobility limitation, hip fractures, and mortality. Follow-up time ranged from 1 year for falls to 8.8 ± 2.3 years for mortality.

SETTING

Eight prospective observational cohort studies.

PARTICIPANTS

A total of 13,421 community-dwelling men and 4,828 community-dwelling women. MEASUREMENTS Grip strength by hand dynamometry, gait speed, and lean mass by DXA.

RESULTS

Low grip strength (absolute or standardized to body size/composition) was associated with incident outcomes, usually independently of slowness, in both men and women. ORs and HRs generally ranged from 1.2 to 3.0 for those below vs above the cut-point. DXA lean mass was not consistently associated with these outcomes. When considered together, those who had both muscle weakness by absolute grip strength (<35.5 kg in men and <20 kg in women) and slowness were consistently more likely to have a fall, hip fracture, mobility limitation, or die than those without either slowness or muscle weakness.

CONCLUSION

Older men and women with both muscle weakness and slowness have a higher likelihood of adverse health outcomes. These results support the inclusion of grip strength and walking speed as components in a summary definition of sarcopenia. J Am Geriatr Soc 68:1429-1437, 2020.

Sarcopenia Definition: The Position Statements of the Sarcopenia Definition and Outcomes Consortium

OBJECTIVES

To develop an evidence-based definition of sarcopenia that can facilitate identification of older adults at risk for clinically relevant outcomes (eg, self-reported mobility limitation, falls, fractures, and mortality), the Sarcopenia Definition and Outcomes Consortium (SDOC) crafted a set of position statements informed by a literature review and SDOC's analyses of eight epidemiologic studies, six randomized clinical trials, four cohort studies of special populations, and two nationally representative population-based studies.

METHODS

Thirteen position statements related to the putative components of a sarcopenia definition, informed by the SDOC analyses and literature synthesis, were reviewed by an independent international expert panel (panel) iteratively and voted on by the panel during the Sarcopenia Position Statement Conference. Four position statements related to grip strength, three to lean mass derived from dual-energy x-ray absorptiometry (DXA), and four to gait speed; two were summary statements.

RESULTS

The SDOC analyses identified grip strength, either absolute or scaled to measures of body size, as an important discriminator of slowness. Both low grip strength and low usual gait speed independently predicted falls, self-reported mobility limitation, hip fractures, and mortality in community-dwelling older adults. Lean mass measured by DXA was not associated with incident adverse health-related outcomes in community-dwelling older adults with or without adjustment for body size.

CONCLUSION

The panel agreed that both weakness defined by low grip strength and slowness defined by low usual gait speed should be included in the definition of sarcopenia. These position statements offer a rational basis for an evidence-based definition of sarcopenia. The analyses that informed these position statements are summarized in this article and discussed in accompanying articles in this issue of the journal. J Am Geriatr Soc 68:1410-1418, 2020.

Application of Selected Muscle Strength and Body Mass Cut Points for the Diagnosis of Sarcopenia in Men and Women With or at Risk for HIV Infection

BACKGROUND

Persons with HIV may experience greater mobility limitations than uninfected populations. Accurate tools are needed to identify persons at greatest risk of decline. We evaluated the performance of novel muscle weakness metrics (grip, grip/body mass index [BMI], grip/weight, grip/total body fat, grip/arm lean mass) and association with slowness and falls in older persons with or at risk for HIV infection as part of the work of the Sarcopenia Definitions and Outcomes Consortium (SDOC).

METHODS

We assessed the prevalence of sarcopenia among 398 men (200 HIV+, 198 HIV-) from the Multicenter AIDS Cohort Study and 247 women (162 HIV+, 85 HIV-) from the Women's Interagency HIV Study using previously validated muscle weakness metrics discriminative of slowness. Sensitivity and specificity were used to compare new muscle weakness and slowness criteria to previously proposed sarcopenia definitions.

RESULTS

The prevalence of muscle weakness ranged from 16% to 66% among men and 0% to 47% among women. Grip/BMI was associated with slowness among men with HIV only. Grip/BMI had low sensitivity (25%-30%) with moderate to high specificity (68%-89%) for discriminating of slowness; all proposed metrics had poor performance in the discrimination of slowness (area under the curve [AUC] < 0.62) or fall status (AUC < 0.56). The combination of muscle weakness and slowness was not significantly associated with falls (p ≥ .36), with a low sensitivity in identifying those sustaining one or more falls (sensitivity ≤ 16%).

DISCUSSION

Clinical utility of new sarcopenia metrics for identification of slowness or falls in men and women with or at risk for HIV is limited, given their low sensitivity.

Application of SDOC Cut Points for Low Muscle Strength for Recovery of Walking Speed After Hip Fracture

BACKGROUND

Sarcopenia is often conceptualized as a precursor to loss of mobility, but its effect on recovery of mobility after a hip fracture is unknown. We determined the prevalence of low muscle strength (weakness) after hip fracture using putative sarcopenia metrics (absolute grip strength, and grip strength normalized to body mass index, total body fat, arm lean mass, and weight) identified by the Sarcopenia Definitions and Outcomes Consortium (SDOC).

METHODS

We examined two well-characterized hip fracture cohorts of community-dwelling older adults from the Baltimore Hip Studies (BHS). The prevalence of muscle weakness was assessed using the SDOC cut points compared to published definitions at 2 and 6 months postfracture. We assessed associations of 2-month weakness with 6-month walking speed <0.6 m/s and calculated the sensitivity and specificity in predicting lack of meaningful change in walking speed (change < 0.1 m/s) at 6 months.

RESULTS

Two hundred and forty-six participants (192 women; 54 men) were included; mean (SD) age of 81 (8) for women and 78 (7) for men. At 2 months, 91% women and 78% men exhibited slow walking speed (< 0.6 m/s). SDOC grip strength standardized by weight (<0.34 kg women, <0.45 kg men) was the most prevalent measure of weakness in men (74%) and women (79%) and provided high sensitivity in men (86%) and women (84%) predicting lack of meaningful change in walking speed at 6 months, although specificity was poor to moderate.

CONCLUSIONS

SDOC cut points for grip strength standardized to weight provided consistent indication of poor walking speed performance post-hip fracture.