Estimation of Skeletal Muscle Mass Relative to Adiposity Improves Prediction of Physical Performance and Incident Disability

Association of body mass index-adjusted calf circumference with appendicular skeletal muscle mass and fall risk in older adults

PURPOSE

This study aims to evaluate the utility of body mass index (BMI)-adjusted calf circumference (CC) in estimating skeletal muscle mass and diagnosing sarcopenia, as well as its association with falls, a common adverse event in sarcopenia.

METHODS

This study used cross-sectional and longitudinal designs. The CC cut-off values and the diagnosis of sarcopenia were based on valid diagnostic criteria. BMI-adjusted CC was based on previous studies, with muscle mass measured by dual-energy X-ray absorptiometry. To evaluate the diagnostic performance of BMI-adjusted CC for low muscle mass and sarcopenia, receiver operating characteristic curves were generated, and the area under the curve (AUC) values were compared using DeLong's test. Over a 1 year follow-up period, factors associated with falls were examined using logistic regression analysis.

RESULTS

In the study of 901 older adults (77.6 ± 6.1 years, 63.6% women), 38.1% of men and 42.1% of women had a BMI outside the 18.5-24.9 kg/m2 range. BMI-adjusted CC significantly lowered the AUC values for diagnosing low skeletal muscle mass and sarcopenia in both sexes (P < 0.001). Longitudinal univariate logistic regression analysis in women revealed that unadjusted CC was not significantly associated with fall risk, whereas BMI-adjusted CC significantly reduced fall risk at higher values. However, this association was no longer present in the multivariate analysis.

CONCLUSION

The utility of BMI-adjusted CC in assessing skeletal muscle mass was not confirmed. The potential value of BMI-adjusted CC has been suggested regarding falls. Further research is warranted to better elucidate these findings.

Growth and physical development of children at apparent risk of sarcopenia

BACKGROUND

The consequences of sarcopenia on growth have received little attention. We analysed the potential risk resulting from the low lean mass for age expressed through the appendicular lean body mass index (aLBMI) and the ratio aLBM/trunk fat mass (trFM).

METHODS

The sample consisted of 580 participants 10-13 yrs evaluated twice in a 12-month interval: height, trFM, total and aLBM, whole-body bone mineral density less head (WBLH BMD), tibia and radius SOS, maturity and handgrip strength were measured. All variables except maturity and BMI were standardised according to sex and age group (Z-score) using the sample as a reference. A high risk of sarcopenia was identified for Z-scores ≤ -1 on aLBMI (Group B) or aLBM/trFM (Group C), while Z-scores > -1 on both markers were considered at low risk for sarcopenia (Group A). The ANCOVA adjusted for maturity was used to compare the three groups.

RESULTS

Girls showed a more significant decrease in the total BMC/LBM ratio in Group B and a minor increase in WBLH BMD in Group C (p < 0.050); boys in Group B showed a tendency to gain less height (p = 0.053).

CONCLUSION

The high risk of sarcopenia expressed through aLBMI or aLBM/trFM Z-score ≤ -1 compromises bone mineralisation in girls.

IMPACT

The findings emphasise the necessity of implementing routine screening protocols for sarcopenia risk within clinical environments and educational institutions. Such screenings should extend beyond merely assessing body mass index to encompass broader body composition variables like lean body mass. By integrating these assessments into routine health evaluations, healthcare professionals and educators can proactively identify at-risk individuals and initiate timely interventions for suboptimal physical growth and development.

Strength training is more effective than aerobic exercise for improving glycaemic control and body composition in people with normal-weight type 2 diabetes: a randomised controlled trial

AIMS/HYPOTHESIS

Type 2 diabetes in people in the healthy weight BMI category (<25 kg/m2), herein defined as 'normal-weight type 2 diabetes', is associated with sarcopenia (low muscle mass). Given this unique body composition, the optimal exercise regimen for this population is unknown.

METHODS

We conducted a parallel-group RCT in individuals with type 2 diabetes (age 18-80 years, HbA1c 47.5-118.56 mmol/mol [6.5-13.0%]) and BMI <25 kg/m2). Participants were recruited in outpatient clinics or through advertisements and randomly assigned to a 9 month exercise programme of strength training alone (ST), aerobic training alone (AER) or both interventions combined (COMB). We used stratified block randomisation with a randomly selected block size. Researchers and caregivers were blinded to participants' treatment group; however, participants themselves were not. Exercise interventions were conducted at community-based fitness centres. The primary outcome was absolute change in HbA1c level within and across the three groups at 3, 6 and 9 months. Secondary outcomes included changes in body composition at 9 months. Per adherence to recommended exercise protocol (PP) analysis included participants who completed at least 50% of the sessions.

RESULTS

Among 186 individuals (ST, n=63; AER, n=58; COMB, n=65) analysed, the median (IQR) age was 59 (53-66) years, 60% were men and 83% were Asian. The mean (SD) HbA1c level at baseline was 59.6 (13.1) mmol/mol (7.6% [1.2%]). In intention-to-treat analysis, the ST group showed a significant decrease in HbA1c levels (mean [95% CI] -0.44 percentage points [-0.78, -0.12], p=0.002), while no significant change was observed in either the COMB group (-0.35 percentage points, p=0.13) or the AER group (-0.24 percentage points, p=0.10). The ST group had a greater improvement in HbA1c levels than the AER group (p=0.01). Appendicular lean mass relative to fat mass increased only in the ST group (p=0.0008), which was an independent predictor of HbA1c change (beta coefficient -7.16, p=0.01). Similar results were observed in PP analysis. Only one adverse event, in the COMB group, was considered to be possibly associated with the exercise intervention.

CONCLUSIONS/INTERPRETATION

In normal-weight type 2 diabetes, strength training was superior to aerobic training alone, while no significant difference was observed between strength training and combination training for HbA1c reduction. Increased lean mass relative to decreased fat mass was an independent predictor of reduction in HbA1c level.

TRIAL REGISTRATION

ClinicalTrials.gov NCT02448498.

FUNDING

This study was funded by the National Institutes of Health (NIH; R01DK081371).

Sarcopenia in Immune-Mediated Rheumatic Diseases-Review

INTRODUCTION

Sarcopenia is a condition characterized by decreased muscle strength and muscle mass, which can impact physical function. Sarcopenia develops as a consequence of age-related decline (primary sarcopenia) and has a major impact on physical, social, and emotional well-being. In addition, patients with rheumatic diseases may suffer from sarcopenia independently of aging (secondary sarcopenia). Exercise, pharmacological treatments, and nutritional supplementation are some of the strategies used for the management of sarcopenia in the general population. The aim of this review is to summarize the evidence around the prevalence and impact of sarcopenia in patients with rheumatic diseases.

CONCLUSIONS

From our review, we can state that sarcopenia is a common and prevalent condition among the rheumatic diseases. Furthermore, the impacts of sarcopenia are not well-appreciated, and the implementation of treatment strategies has not been widespread. Strategies such as exercise and some pharmacological treatments are effective in improving physical and functional impairment related to these conditions.

FUTURE RESEARCH DIRECTIONS IN THE FIELD

New pharmacological treatments are being actively studied and may contribute in the future to the management of sarcopenia.

Adipocytokines and Associations With Abnormal Body Composition in Rheumatoid Arthritis

OBJECTIVE

We determined associations between adipokines and abnormal body composition in patients with rheumatoid arthritis (RA).

METHODS

Combining data from three RA cohorts, whole-body dual-energy absorptiometry measures of appendicular lean mass and fat mass indices were converted to age-, sex-, and race- and ethnicity-specific Z scores. Lean mass relative to fat mass was determined based on prior methods. Independent associations between body composition profiles and circulating levels of adiponectin, leptin, and fibroblast growth factor (FGF)-21 were assessed using linear and logistic regression models adjusting for demographic characteristics and study cohort. We also determined the improvement in the area under the curve (AUC) for prediction of low lean mass when adipokines were added to predictive models that included clinical factors such as demographic characteristics, study, and body mass index (BMI).

RESULTS

Among 419 participants, older age was associated with higher levels of all adipokines, whereas higher C-reactive protein level was associated with lower adiponectin levels and higher FGF-21 levels. Greater fat mass was strongly associated with lower adiponectin levels and higher leptin and FGF-21 levels. Higher levels of adiponectin, leptin, and FGF-21 were independently associated with low lean mass. The addition of adiponectin and leptin levels to regression models improved prediction of low lean mass when combined with demographic characteristics, study, and BMI (AUC 0.75 vs. 0.66).

CONCLUSION

Adipokines are associated with both excess adiposity and low lean mass in patients with RA. Improvements in the prediction of body composition abnormalities suggest that laboratory screening could help identify patients with altered body composition who may be at greater risk of adverse outcomes.

Associations Between Low Serum Urate, Body Composition, and Mortality

OBJECTIVE

Controversy remains as to whether low serum urate or uric acid (UA) levels contribute to adverse outcomes. We evaluated the relation between low serum UA levels and sarcopenia and assessed whether sarcopenia confounds associations between these low levels and mortality.

METHODS

We utilized data from the National Health and Nutrition Examination Survey (1999-2006). Participants with available whole-body dual x-ray absorptiometry body composition measurements and serum UA concentrations were included. Body composition assessments included body mass index (BMI), waist circumference, maximum lifetime BMI, and age-, sex-, and race-specific appendicular lean mass index (ALMI) and fat mass index (FMI) Z scores. We also calculated Z scores for ALMI relative to FMI (ALMIFMI ). We evaluated associations between serum UA levels and body composition using logistic regression and assessed associations between serum UA levels and mortality before and after adjusting for differences in body composition using Cox proportional hazards regression.

RESULTS

Among the 13,979 participants, low serum UA concentrations (<2.5 mg/dl in women, <3.5 mg/dl in men) were associated with low lean mass (ALMI and ALMIFMI Z scores), underweight BMI (<18.5 kg/m2 ), and higher rates of weight loss. The proportion of patients with low ALMI Z scores was 29% in the low serum UA group and 16% in the normal serum UA group (P = 0.001). Low serum UA levels were associated with increased mortality before we adjusted for body composition (hazard ratio 1.61 [95% confidence interval 1.14-2.28]; P = 0.008) but was attenuated and not significant after adjustment for body composition and weight loss (hazard ratio 1.30 [95% confidence interval 0.92-1.85], P = 0.13).

CONCLUSION

Sarcopenia and weight loss are more common among patients with low serum UA concentrations. Differences in body composition may help to explain associations between low levels of serum UA and higher mortality.

Dose-response relationships of sarcopenia parameters with incident disability and mortality in older Japanese adults

BACKGROUND

Sarcopenia-related parameters may have differential impacts on health-related outcomes in older adults. We examined dose-response relationships of body composition, muscle strength, and physical performance with incident disability and mortality.

METHODS

This prospective study included 1765 Japanese residents (862 men; 903 women) aged ≥65 years who participated in health check-ups. Outcomes were incident disability and all-cause mortality. Fat mass index (FMI) and skeletal muscle mass index (SMI), determined using segmental multi-frequency bioelectrical impedance analysis, handgrip strength (HGS), and usual gait speed (UGS) were measured. We determined multivariate-adjusted hazard ratios (HRs) for disability and mortality relative to sex-specific reference values (FMI: medians; SMI: 7.0 kg/m² for men and 5.7 kg/m² for women; HGS: 28 kg for men and 18 kg for women; or UGS: 1.0 m/s for both sexes). Association shapes were examined using restricted cubic splines or fractional polynomial functions.

RESULTS

The median follow-up was 5.3 years; 107 (12.7%) men and 123 (14.2%) women developed disability, and 101 (11.7%) men and 56 (6.2%) women died. FMI did not impact any outcome in men and disability in women, while an FMI ≤ 7.3 kg/m² (median) was significantly associated with higher mortality risk in women, compared with median FMI. SMI did not impact disability in either sex and mortality in women, but showed a significant inverse dose-response relationship with mortality risk in men [HRs (95% confidence intervals) of minimum and maximum values compared with the reference value: 2.18 (1.07-4.46) and 0.43 (0.20-0.93), respectively], independent of HGS and UGS. HGS and UGS showed a significant inverse dose-response relationship with disability in both sexes [HGS: 1.71 (1.00-2.91) and 0.31 (0.09-0.99), respectively, in men, 2.42 (1.18-4.96) and 0.41 (0.20-0.85), respectively, in women; UGS: 2.14 (1.23-3.74) and 0.23 (0.08-0.67), respectively, in men, 3.26 (2.07-5.14) and 0.11 (0.05-0.26), respectively, in women] and mortality in women [HGS: 6.84 (2.84-16.47) and 0.06 (0.02-0.21), respectively; UGS: 2.67 (1.14-6.27) and 0.30 (0.11-0.85), respectively], independent of body composition, but did not impact mortality in men.

CONCLUSIONS

Disability risk was more dependent on muscle strength and physical performance in both sexes. Mortality risk in men was more dependent on muscle mass, and mortality risk in women was influenced by lower fat mass along with muscle strength and physical performance. Although improving muscle strength and physical performance should be the first target for health promotion, it is also necessary to pay attention to body composition to extend life expectancy in older adults.

Associations Between Plasma Growth and Differentiation Factor-15 with Aging Phenotypes in Muscle, Adipose Tissue, and Bone

Growth and differentiation factor 15 (GDF-15) is associated with muscle, fat, and bone metabolism; however, this association has not been well characterized. Plasma GDF-15, appendicular skeletal muscle mass (ASM), fat mass (FM), and bone mineral density (BMD) were measured in 146 postmenopausal women. GDF-15 levels were higher in subjects with low Body Mass Index (BMI)-adjusted ASM than in those without (median [interquartile range] 831.3 [635.4-1011.4] vs. 583.8 [455.8-771.1] pg/mL, p = 0.018). The GDF-15 level was inversely correlated with BMI-adjusted ASM (r =  - 0.377, p < 0.001) and BMD at femur neck (FN-BMD; r =  - 0.201, p = 0.015), and positively correlated with percent FM (pFM; r = 0.328, p < 0.001). After adjusting for confounders, the GDF-15 level was inversely associated with BMI-adjusted ASM (β = -0.250, p = 0.006) and positively associated with pFM (β = 0.272, p = 0.004), and tended to be inversely associated with FN-BMD (β = - 0.176, p = 0.076). The area under the receiver-operating characteristic curve of GDF-15 level > 618.4 pg/mL for sarcopenia was 0.706 (95% confidence interval (CI) 0.625-0.779) with a sensitivity of 83.3% and a specificity of 54.5%. Using a GDF-15 level of 618.4 pg/mL as a cut-off, the GDF-15 level was associated with a significantly greater likelihood of sarcopenia (odds ratio [OR] 2.35; 95% CI 1.00-5.51; p = 0.049), obesity (OR 3.28; 95% CI 1.48-7.27; p = 0.001), osteopenic obesity (OR 3.10; 95% CI 1.31-7.30; p = 0.010), and sarcopenic or osteosarcopenic obesity (OR 4.84; 95% CI 0.88-26.69; p = 0.070). These findings support the potential of GDF-15 as a biomarker for age-related changes in muscle, fat, and bone.

Do Overweight People Have Worse Cognitive Flexibility? Cues-Triggered Food Craving May Have a Greater Impact

Background: Overweight people have been revealed to have poor cognitive flexibility. Cognitive flexibility reflects proactive and reactive control abilities. However, the impairment had not been explicitly positioned at the cognitive stage. Therefore, this study provides increased support for impairment of cognitive flexibility due to overweight. Method: The study included 34 overweight and 35 normal-weight participants. They were required to complete the food and flower target AX-continuous performance test (AX–CPT), including the resting-state fMRI and cue-triggered food craving subscales. We compared the performance difference between the two tasks. Furthermore, we investigated whether the cue-triggered food cravings and the corresponding brain regions mediated the effect of overweight on the two control mechanisms. Result: Significant differences were found only in the food target AX-CPT task, where overweight participants performed worse. Cue-triggered food cravings mediated this relationship. Additionally, we found that the brain regions associated with cue-triggered food cravings (bilateral SFG) can completely mediate the relationship between BMI and the z-value of the fat mass index and sensitivity to proactive control. Conclusion: In the food target task, overweight participants performed worse in both control mechanisms. Moreover, we also revealed the potential mechanism by which being overweight might affect the two control mechanisms through cue-triggered food cravings.

Body composition in individuals with cystic fibrosis

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BMI is used to characterize nutritional status but may not accurately depict body composition in CF.

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DXA and bioelectrical impedance are the most commonly used methods for assessing BC.

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Lower fat-free mass associates with worse pulmonary function and greater CF disease severity.

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Fat-free mass associates with greater bone mineral density in individuals with CF.

Because nutritional status is intimately linked with pulmonary function and survival, nutrition has been at the mainstay of cystic fibrosis (CF) care. Body Mass Index (BMI) is traditionally used to define nutritional status because of the ease with which it can be calculated, but it has a number of limitations including its inability to differentiate fat mass (FM) from lean body mass (LBM), the latter thought to confer health advantage. A number of tools are available to quantify body composition including dual-energy x-ray absorptiometry (DXA), bioelectrical impedance, MRI, CT, air displacement plethysmography, and stable isotopes, and these have been used to varying degrees in studies of CF. In CF, LBM tends to be lower for a given BMI, particularly at lower BMI. In adults, lower fat-free mass (FFM) correlates with greater CF disease severity, lower pulmonary function and higher inflammatory markers. FFM is also positively associated with greater bone mineral density, while greater FM is associated with greater loss of lumbar spine bone mineral density over 2 years. In youth, LBM is positively associated with pulmonary function. The predictive value of body composition for functional and clinical outcomes and the role of improving LBM on these outcomes remain undefined. With improvements in BMI accompanying highly-effective modulator therapy, closer evaluations of body composition may inform risk for more traditional, non-CF adult outcomes in CF.

Sarcopenic Obesity in Rheumatoid Arthritis: Prevalence and Impact on Physical Functioning

OBJECTIVE

We determined the prevalence of sarcopenic obesity in patients with rheumatoid arthritis (RA) using multiple methods and assessed associations with physical functioning.

METHODS

This study evaluated data from three RA cohorts. Whole-body dual-energy absorptiometry (DXA) measures of appendicular lean mass index (ALMI, kg/m2) and fat mass index (FMI) were converted to age, sex, and race-specific Z-Scores and categorized using a recently validated method and compared it to a widely-used existing method. The prevalence of body composition abnormalities in RA was compared with two reference populations. In the RA cohorts, associations between body composition and change in the Health Assessment Questionnaire (HAQ) and the Short Physical Performance Battery (SPPB) in follow-up were assessed using linear and logistic regression, adjusting for age, sex, race, and study.

RESULTS

The prevalence of low lean mass and sarcopenic obesity were higher in patients with RA (14.2; 12.6%, respectively) compared with the reference population cohorts (7-10%; 4-4.5%, respectively, all p< 0.05). There was only moderate agreement among methods of sarcopenic obesity categorization (Kappa 0.45). The recently validated method categorized fewer subjects as obese, and many of these were categorized as low lean mass only. Low lean mass, obesity, and sarcopenic obesity were each associated with higher HAQ and lower SPPB at baseline and numerically greater worsening.

CONCLUSION

RA patients had higher rates of low lean mass and sarcopenic obesity than the general population. The recently validated methods characterized body composition changes differently from traditional methods and were more strongly associated with physical function.

Changes in Body Composition, Muscle Strength, and Fat Distribution Following Kidney Transplantation

RATIONALE AND OBJECTIVE

Low muscle mass relative to fat mass (relative sarcopenia) has been associated with mortality and disability but has not been examined following transplantation. We studied how measures of body composition change after receipt of a kidney allograft.

STUDY DESIGN

Prospective longitudinal cohort study.

SETTING AND PARTICIPANTS

60 kidney transplant recipients (ages 20-60 years) at the University of Pennsylvania.

EXPOSURE

Kidney transplantation.

OUTCOMES

DXA measures of fat mass index (FMI) and appendicular lean mass index (ALMI; representing muscle mass), CT measures of muscle density (low density represents increased intramuscular adipose tissue), dynamometer measures of leg muscle strength, and physical activity. ALMI relative to FMI (ALM_FMI) is an established index of relative sarcopenia.

ANALYTICAL APPROACH

Measures expressed as age, sex, and race-specific Z-scores for transplant recipients were compared to 327 healthy controls. Regression models were used to identify correlates of change in outcome Z-scores and compare transplant recipients to controls.

RESULTS

At transplantation, ALMI, ALMI_FMI, muscle strength and muscle density Z-scores were lower vs. controls (all p≤0.001). Transplant recipients received glucocorticoids throughout. The prevalence of obesity increased from 18 to 45%. Although ALMI increased following transplantation (p<0.001) and was comparable to controls from 6 months onward, gains were outpaced by increases in FMI, resulting in persistent ALMI_FMI deficits (mean Z-score -0.31 at 24 months, p=0.02 vs controls). Muscle density improved following transplantation despite gains in FMI (p = 0.02). Muscle strength relative to ALMI also improved (p = 0.04) but remained low compared with controls (p=0.01). Exercise increased in the early months following transplantation (p<0.05) but remained lower than controls (p=0.02).

LIMITATIONS

Lack of muscle biopsies precluded assessment of muscle histology and metabolism.

CONCLUSIONS

The two-year interval following kidney transplantation was characterized by gains in muscle mass and strength that were outpaced by gains in fat mass resulting in persistent relative sarcopenia.

Factors associated with sarcopenia screened by finger-circle test among middle-aged and older adults: a population-based multisite cross-sectional survey in Japan

BACKGROUND

Previous epidemiological studies have demonstrated the prevalence and relationship of various factors associated with sarcopenia in older adults; however, few have examined the status of sarcopenia in middle-aged adults. In this study, we aimed to, 1) evaluate the validity of the finger-circle test, which is potentially a useful screening tool for sarcopenia, and 2) determine the prevalence and factors associated with sarcopenia in middle-aged and older adults.

METHODS

We conducted face-to-face surveys of 525 adults, who were aged 40-91 years and resided in Settsu City, Osaka Prefecture, Japan to evaluate the validity of finger-circle test. The finger-circle test evaluated calf circumference by referring to an illustration printed on the survey form. The area under the receiver operating characteristic curves (AUROC) was plotted to evaluate the validity of the finger-circle test for screening sarcopenia and compared to that evaluated by skeletal muscle mass index (SMI) measured using bioimpedance. We also conducted multisite population-based cross-sectional anonymous mail surveys of 9337 adults, who were aged 40-97 years and resided in Settsu and Hannan Cities, Osaka Prefecture, Japan. Participants were selected through stratified random sampling by sex and age in the elementary school zones of their respective cities. We performed multiple logistic regression analysis to explore associations between characteristics and prevalence of sarcopenia.

RESULTS

Sarcopenia, defined by SMI, was moderately predicted by a finger-circle test response showing that the subject's calf was smaller than their finger-circle (AUROC: 0.729, < 65 years; 0.653, ≥65 years); such subjects were considered to have sarcopenia. In mail surveys, prevalence of sarcopenia screened by finger-circle test was higher in older subjects (approximately 16%) than in middle-aged subjects (approximately 8-9%). In a multiple regression model, the factors associated with sarcopenia were age, body mass index, smoking status, self-reported health, and number of meals in all the participants.

CONCLUSIONS

Sarcopenia, screened by the finger-circle test, was present not only among older adults but also among middle-aged adults. These results may provide useful indications for developing public health programs, not only for the prevention, but especially for the management of sarcopenia.

TRIAL REGISTRATION

UMIN000036880, registered prospectively May 29, 2019,  https://upload.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000042027.

Association of Low Muscle Density With Deteriorations in Muscle Strength and Physical Functioning in Rheumatoid Arthritis

OBJECTIVE

Rheumatoid arthritis (RA) is associated with low muscle density due to the accumulation of intramuscular fat. The present study was undertaken to identify predictors of changes in muscle density and to determine whether low muscle density predicted changes in strength and physical function.

METHODS

Patients with RA, ages 18-70 years, completed whole-body dual-energy x-ray absorptiometry and peripheral quantitative computed tomography to quantify lean and fat mass indices and muscle density. Dynamometry was used to measure strength at the hand, knee, and lower leg. Disability and physical function were measured with the Health Assessment Questionnaire (HAQ) and the Short Physical Performance Battery (SPPB). Assessments were performed at baseline and at follow-up. Regression analyses assessed associations between patient characteristics, muscle density, and deteriorations in strength and function.

RESULTS

Muscle density was assessed at baseline in 107 patients with RA. Seventy-nine of these patients (74%) returned for a follow-up assessment at a median follow-up time of 2.71 years (interquartile range 2.35-3.57). Factors associated with declines in muscle density included female sex, higher disease activity, smoking, and lower insulin-like growth factor 1 (IGF-1) levels. Greater muscle density Z score at baseline (per 1 SD) was associated with less worsening per year according to HAQ, SPPB, and 4-meter walk time scores and a lower risk of a clinically important worsening in HAQ score (odds ratio [OR] 1.90 [95% confidence interval (95% CI) 1.06, 3.42]; P = 0.03) and walking speed (OR 2.87 [95% CI 1.05, 7.89]; P = 0.04).

CONCLUSION

Worsening of skeletal muscle density occurred in patients with higher disease activity, in smokers, and in those with lower IGF-1. Low muscle density was associated with worsening of physical function. Interventions addressing reductions in muscle quality might prevent functional decline.

Validation of a description of sarcopenic obesity defined as excess adiposity and low lean mass relative to adiposity

BACKGROUND

This study aims to assess the construct validity of a body composition-defined definition of sarcopenic obesity based on low appendicular lean mass relative to fat mass (ALMIFMI ) and high fat mass index (FMI) and to compare with an alternative definition using appendicular lean mass index (ALMI) and percent body fat (%BF).

METHODS

This is a secondary analysis of two cohort studies: the National Health and Examination Survey (NHANES) and the Health, Aging, and Body Composition study (Health ABC). Sarcopenic obesity was defined as low ALMIFMI combined with high FMI and was compared with a widely used definition based on ALMI and %BF cut-points. Body composition Z-scores, self-reported disability, physical functioning, and incident disability were compared across body composition categories using linear and logistic regression and Cox proportional hazards models.

RESULTS

Among 14, 850 participants from NHANES, patients with sarcopenic obesity defined by low ALMIFMI and high FMI (ALMIFMI -FMI) had above-average FMI Z-scores [mean (standard deviation): 1.00 (0.72)]. In contrast, those with sarcopenic obesity based on low ALMI and high %BF (ALMI-%BF) had below-average FMI Z-scores. A similar pattern was observed for 2846 participants from Health ABC. Participants with sarcopenic obesity based on ALMIFMI -FMI had a greater number of disabilities, worse physical function, and a greater risk of incident disability compared with those defined based on ALMI-%BF.

CONCLUSIONS

Body composition-defined measures of sarcopenic obesity defined as excess adiposity and lower-than-expected ALMI relative to FMI are associated with functional deficits and incident disability and overcome the limitations of using %BF in estimating obesity in this context.

Diagnosis of sarcopenia in primary health care

With aging, there is a loss of skeletal muscle mass and function, which leads to an increased risk of falls, fractures, long-term institutional care, cardiovascular and metabolic diseases, and even mortality. Sarcopenia has been defined as a condition characterized by low muscle mass together with low muscle strength and/or low muscle performance. In 2019, the Asian Working Group for Sarcopenia (AWGS) published a consensus paper on the diagnosis and treatment of sarcopenia. The AWGS 2019 guideline, in particular, presented strategies for case-finding and assessment, which could aid in the diagnosis of possible sarcopenia in primary care settings. AWGS 2019 proposed an algorithm that recommends calf circumference measurement (cut-off <34 cm in men, <33 cm in women) or the SARC-F (strength, assistance in walking, rising from a chair, climbing stairs, falls) questionnaire (cut-off ≥4), followed by handgrip strength measurement (cut-off <28 kg in men, <18 kg in women) or the 5-time chair stand test (≥12 seconds). Finally, “possible sarcopenia” is defined by either low muscle strength (handgrip strength) or low physical performance (5-time chair stand test). This paper will address the way in which sarcopenic patients can be identified and assessed practically in primary care settings.

Protein Intake and Functional Integrity in Aging: The Framingham Heart Study Offspring

BACKGROUND

Higher protein intake is linked to maintenance of muscle mass and strength, but few studies have related protein to physical function and disability in aging.

METHODS

In participants of the Framingham Heart Study Offspring, we examined associations between protein intake (g/d), estimated from food frequency questionnaires, and maintenance of functional integrity, as a functional integrity score based on responses to 17 questions from Katz Activities of Daily Living, Nagi, and Rosow-Breslau questionnaires, repeated up to five times (1991/1995-2011/2014) over 23 years of follow-up. Cox proportional hazard models were used to estimate risk of incident loss of functional integrity (functional integrity score ≤ 15th percentile).

RESULTS

In 2,917 participants (age 54.5 [9.8] years), baseline protein intake was 77.2 (15.6) g/d. The functional integrity score (baseline, mean 98.9, range 82.4-100.0) was associated with objective performance (gait speed, grip strength) and lower odds of falls, fractures, and frailty. Across follow-up, there were 731 incident cases of loss of functional integrity. In fully adjusted models, participants in the highest category of protein intake (median 92.2 g/d) had 30% lower risk of loss of functional integrity (hazard ratio [95% confidence interval] 0.70 [0.52, 0.95], p trend = .03), versus those with the lowest intake (median 64.4 g/d). However, sex-stratified analyses indicated the association was driven by the association in women alone (hazard ratio [95% confidence interval] 0.49 [0.32, 0.74], p trend = .002) and was nonsignificant in men (hazard ratio [95% confidence interval] 1.14 [0.70, 1.86], p trend = .59).

CONCLUSIONS

Higher protein intake was beneficially associated with maintenance of physical function in middle-aged, high-functioning U.S. adults over the span of two decades. This association was particularly evident in women.

Asian Working Group for Sarcopenia: 2019 Consensus Update on Sarcopenia Diagnosis and Treatment

Clinical and research interest in sarcopenia has burgeoned internationally, Asia included. The Asian Working Group for Sarcopenia (AWGS) 2014 consensus defined sarcopenia as "age-related loss of muscle mass, plus low muscle strength, and/or low physical performance" and specified cutoffs for each diagnostic component; research in Asia consequently flourished, prompting this update. AWGS 2019 retains the previous definition of sarcopenia but revises the diagnostic algorithm, protocols, and some criteria: low muscle strength is defined as handgrip strength <28 kg for men and <18 kg for women; criteria for low physical performance are 6-m walk <1.0 m/s, Short Physical Performance Battery score ≤9, or 5-time chair stand test ≥12 seconds. AWGS 2019 retains the original cutoffs for height-adjusted muscle mass: dual-energy X-ray absorptiometry, <7.0 kg/m2 in men and <5.4 kg/m2 in women; and bioimpedance, <7.0 kg/m2 in men and <5.7 kg/m2 in women. In addition, the AWGS 2019 update proposes separate algorithms for community vs hospital settings, which both begin by screening either calf circumference (<34 cm in men, <33 cm in women), SARC-F (≥4), or SARC-CalF (≥11), to facilitate earlier identification of people at risk for sarcopenia. Although skeletal muscle strength and mass are both still considered fundamental to a definitive clinical diagnosis, AWGS 2019 also introduces "possible sarcopenia," defined by either low muscle strength or low physical performance only, specifically for use in primary health care or community-based health promotion, to enable earlier lifestyle interventions. Although defining sarcopenia by body mass index-adjusted muscle mass instead of height-adjusted muscle mass may predict adverse outcomes better, more evidence is needed before changing current recommendations. Lifestyle interventions, especially exercise and nutritional supplementation, prevail as mainstays of treatment. Further research is needed to investigate potential long-term benefits of lifestyle interventions, nutritional supplements, or pharmacotherapy for sarcopenia in Asians.

Obesity, Weight Loss, and Progression of Disability in Rheumatoid Arthritis

OBJECTIVE

Cross-sectional studies have demonstrated that obese patients with rheumatoid arthritis (RA) often report greater disability. The longitudinal effects of obesity, however, are not well-characterized. We evaluated associations between obesity, weight loss, and worsening of disability in patients of 2 large registry studies, which included patients who were followed for longer periods of time.

METHODS

This study included patients with RA from the National Data Bank for Rheumatic Diseases (FORWARD) (n = 23,323) and the Veterans Affairs RA (VARA) registry study (n = 1,697). Results of the Health Assessment Questionnaire (HAQ) or Multidimensional HAQ (MD-HAQ) were recorded through follow-up. Significant worsening of disability was defined as an increase of >0.2 in HAQ or MD-HAQ scores. The Cox proportional hazards model was used to evaluate the risk of worsening of disability from baseline and to adjust for demographics, baseline disability, comorbidity, disease duration, and other disease features.

RESULTS

At enrollment, disability scores were higher among severely obese patients compared to those who were overweight both in FORWARD (β = 0.17 [95% confidence interval (95% CI) 0.14, 0.20]; P < 0.001) and in the VARA registry (β = 0.17 [95% CI 0.074, 0.27]; P = 0.001). In multivariable models, patients who were severely obese at enrollment had a greater risk of progressive disability compared to overweight patients in FORWARD (HR 1.25 [95% CI 1.18, 1.33] P < 0.001) and in the VARA registry (HR 1.33 [95% CI 1.07, 1.66]; P = 0.01). Weight loss following enrollment was also associated with a greater risk in both cohorts. In the VARA registry, associations were independent of other clinical factors, including time-varying C-reactive protein and swollen joint count.

CONCLUSION

Severe obesity is associated with a more rapid progression of disability in RA. Weight loss is also associated with worsening disability, possibly due to it being an indication of chronic illness and the development of age-related or disease-related frailty.

Relative sarcopenia and mortality and the modifying effects of chronic kidney disease and adiposity

BACKGROUND

Conventional definitions of sarcopenia based on lean mass may fail to capture low lean mass relative to higher fat mass, that is, relative sarcopenia. The objective of this study is to determine the associations of sarcopenia and relative sarcopenia with mortality independent of co-morbidities, and whether chronic kidney disease (CKD) and adiposity alter these associations.

METHODS

Dual energy X-ray absorptiometry-derived appendicular lean mass index (ALMI, kg/m2 ) and fat mass index (FMI, kg/m2 ) were assessed in 14 850 National Health and Nutrition Examination Survey participants from 1999 to 2006 and were linked to death certificate data in the National Death Index with follow-up through 2011. Sarcopenia was defined using sex-specific and race/ethnicity-specific standard deviation scores compared with young adults (T-scores) as an ALMI T-score < -2 and relative sarcopenia as fat-adjusted ALMI (ALMIFMI ) T-score < -2. Glomerular filtration rate (GFR) was estimated using creatinine-based (eGFRCr ) and cystatin C-based (eGFRCys ) regression equations.

RESULTS

Three (3.0) per cent of National Health and Nutrition Examination Survey participants met criteria for sarcopenia and 8.7% met criteria for relative sarcopenia. Sarcopenia and relative sarcopenia were independently associated with mortality (HR sarcopenia 2.20, 95% CI 1.69 to 2.86; HR relative sarcopenia 1.60, 95% CI 1.31 to 1.96). The corresponding population attributable risks were 5.2% (95% CI 3.4% to 6.4%) and 8.4% (95% CI 4.8% to 11.2%), respectively. Relative sarcopenia remained significantly associated with mortality (HR 1.32, 95% CI 1.08 to 1.61) when limited to the subset who did not meet the criteria for sarcopenia. The risk of mortality associated with relative sarcopenia was attenuated among persons with higher FMI (P for interaction <0.01) and was not affected by CKD status for either sarcopenia or relative sarcopenia.

CONCLUSIONS

Sarcopenia and relative sarcopenia are significantly associated with mortality regardless of CKD status. Relative sarcopenia is nearly three-fold more prevalent amplifying its associated mortality risk at the population level. The association between relative sarcopenia and mortality is attenuated in persons with higher FMI.

Bone Mineral Density, TBS, and Body Composition Indexes in Ukrainian Men with Parkinson's Disease

INTRODUCTION

Current research studies demonstrate the changes of bone mineral density (BMD) in subjects with Parkinson's disease (PD); however, data about bone quality and body composition (BC) indexes are insufficient. The aim of the study was to assess the parameters of BMD, ВС, and trabecular bone score (TBS) in PD males.

MATERIALS AND METHODS

We performed a cross-sectional case-control research design and examined 76 males aged 50-77 years old, who were divided into two groups: first group including men without PD (n=38) and the second group including subjects with PD (n=38). Disease duration was at least 5 years; all PD participants were at levodopa therapy. BMD of lumbar spine, femoral neck, total femur, radius, and total body and TBS L l-L 4 were measured using the DXA method. Whole-body DXA measures were also used for the study of total, lean, and fat masses, skeletal muscle index (SMI), appendicular lean mass index (ALMI), and fat mass index (FMI).

RESULTS

Our study showed an increased incidence of osteoporosis and significantly lower total body BMD (respectively, 1.20 ± 0.13 and 1.26 ± 0.10 g/cm2, p=0.05), but not lumbar spine and femoral neck BMDs, and higher TBS value in PD men comparing to the control group (respectively, 1.33 ± 0.12 and 1.22 ± 0.18 un., p=0.005). Also, we established significantly decreased lower extremities BMD indexes, but not upper extremities, spine, and trunk BMDs in PD males. The femoral neck, proximal femur, and lower extremities BMD indexes in PD men were reliably lower at the side of predominance of clinical symptoms. Parameters of appendicular lean mass and ALMI in PD males were reliably higher, but fat mass values and FMI were lower compared to the control group in the absence of significant differences in lean mass values and SMI in weight-matched control.

CONCLUSION

Due to low BMD values, changes in BC are present in PD males, and appropriate screening and preventive strategies should be instigated to maintain bone health in PD subjects.

Intramuscular Fat Accumulation and Associations With Body Composition, Strength, and Physical Functioning in Patients With Rheumatoid Arthritis

OBJECTIVE

Rheumatoid arthritis (RA) is associated with adverse body composition profiles and low muscle density due to the accumulation of intramuscular fat. Linear regression was used to assess differences between RA patients and controls and to determine associations between muscle density, strength, and physical functioning.

METHODS

Patients with RA, ages 18-70 years, and healthy control subjects underwent whole-body dual x-ray absorptiometry and peripheral quantitative computed tomography, in order to quantify the appendicular lean mass index (ALMI) and the fat mass index (FMI), visceral fat area, and muscle density. Dynamometry was used to measure hand grip strength and muscle strength at the knee and lower leg. Disability and physical functioning were measured using the Health Assessment Questionnaire (HAQ) and the Short Physical Performance Battery (SPPB). Linear regression analyses were performed to assess differences related to RA and associations between muscle density, strength, and function.

RESULTS

The study group included 103 patients with RA (51 men) and 428 healthy control subjects. Among patients with RA, low muscle density was associated with higher disease activity, C-reactive protein and interleukin-6 levels, greater total and visceral fat area, lower ALMI Z scores, physical inactivity, and long-term use of glucocorticoids (>1 year). Patients with low ALMI Z scores had lower muscle density Z scores compared with reference participants with similarly low ALMI scores. Low muscle density was independently associated with lower muscle strength, higher HAQ scores, and lower SPPB scores, after adjustment for ALMI and FMI Z scores.

CONCLUSION

The low muscle density observed in patients with RA was associated with low muscle mass, excess adiposity, poor strength, and greater disability. Interventions to address poor muscle quality could potentially affect important functional outcomes.

The impact of DXA-derived fat-free adipose tissue on the prevalence of low muscle mass in older adults

BACKGROUND/OBJECTIVES

To investigate the impact of eliminating fat-free adipose tissue (aFFAT) on the prevalence of low muscle mass in older adults.

SUBJECTS/METHODS

Three hundred and forty-three (153 men and 190 women) well-functioning Japanese older adults (aged 65-79) had their appendicular lean mass (aLM) and appendicular fat mass (aFM) measured using dual-energy X-ray absorptiometry (DXA). aFFAT was then estimated from DXA-derived aFM (aFM = (FM/0.15)*0.85). Both traditional cutoffs and those corrected for aFFAT were used for diagnosing low muscle mass.

RESULTS

With traditional cutoff values, the prevalence of low muscle mass using the unadjusted aLM index was 20.1%. After adjusting the aLM index for aFFAT, the prevalence increased to 49.0% (p < 0.001). However, when the cutoff values were also adjusted for aFFAT, the prevalence of low muscle mass only increased to 23.0% (p < 0.001). Further, ~5% of the participants (7 men and 8 women) were newly classified as having low muscle mass after correction for aFFAT. However, several women (n = 5) were not classified as having low muscle mass using the corrected cutoff value, although they would have been when using the non-corrected cutoff.

CONCLUSIONS

Adjusting for the effect of aFFAT on DXA-derived aLM significantly increases the prevalence of low muscle mass in older adults. For clinical research and practice, the influence of aFFAT on DXA-derived aLM may need to be taken into consideration when diagnosing low muscle mass.