Impact of Different Operational Definitions of Sarcopenia on Prevalence in a Population-Based Sample: The Salus in Apulia Study

Are inflammatory markers associated with sarcopenia-related traits in older adults with sarcopenia? - A cross-sectional analysis of the ENHANce study

AIMS

To explore the relationship between inflammatory markers and sarcopenia-related traits in sarcopenic older adults.

METHODS

Baseline data of the ongoing Exercise and Nutrition for Healthy AgeiNg (ENHANce) study were used for a secondary, exploratory, cross-sectional analysis. ENHANce is a 5-armed triple blinded randomized controlled trial, in older adults (>65y) with sarcopenia defined according to the revised criteria of the European Working Group of Sarcopenia in Older People (EWGSOP2) aiming to assess the effect of combined anabolic interventions (protein supplement, omega-3 supplement and physical exercise) on physical performance, compared to single/placebo interventions. Inflammatory markers C-reactive protein (hs-CRP), albumin, interleukin-1β (IL-1β), IL-6, IL-8, and tumour necrosis factor-α (TNF-α) were assessed at baseline. Spearman's rho (ρ) correlation coefficients were calculated to associate these inflammatory markers with baseline sarcopenia-defining parameters (handgrip strength, chair stand test, appendicular lean mass [aLM], gait speed, Short Physical Performance Battery), physical activity (step count) and quality of life (SF-36, SarQoL).

RESULTS

We included 40 sarcopenic subjects (15 men/25 women, age 77.1 ± 6.8 years). Contrary to expectations, the pro-inflammatory IL-1β correlated positively with handgrip strength (ρ: 0.376; p = 0.024) and IL-6 with aLM (ρ: 0.334; p = 0.0433). IL-6 inversely correlated with step count (ρ:-0.358; p = 0.048). Subgroup analysis revealed important gender differences. IL-8 inversely correlated with handgrip strength in women (ρ: -0.425; p = 0.034) but not in men. In contrast, pro-inflammatory cytokines CRP (ρ: -0.615; p = 0.019), IL-6 (ρ: -0.604; p = 0.029) and TNF-α (ρ: -0.615; p = 0.025) inversely correlated with the SF-36 physical component score in men but not in women.

CONCLUSION

Although Inflammageing might play a role in sarcopenia-related traits, this exploratory study highlights an important role of gender. Future research should take this into account when elucidating the Inflammageing-sarcopenia interplay.

A Machine-Learning Approach to Target Clinical and Biological Features Associated with Sarcopenia: Findings from Northern and Southern Italian Aging Populations

Epidemiological and public health resonance of sarcopenia in late life requires further research to identify better clinical markers useful for seeking proper care strategies in preventive medicine settings. Using a machine-learning approach, a search for clinical and fluid markers most associated with sarcopenia was carried out across older populations from northern and southern Italy. A dataset of adults >65 years of age (n = 1971) made up of clinical records and fluid markers from either a clinical-based subset from northern Italy (Pavia) and a population-based subset from southern Italy (Apulia) was employed (n = 1312 and n = 659, respectively). Body composition data obtained by dual-energy X-ray absorptiometry (DXA) were used for the diagnosis of sarcopenia, given by the presence of either low muscle mass (i.e., an SMI < 7.0 kg/m² for males or <5.5 kg/m² for females) and of low muscle strength (i.e., an HGS < 27 kg for males or <16 kg for females) or low physical performance (i.e., an SPPB ≤ 8), according to the EWGSOP2 panel guidelines. A machine-learning feature-selection approach, the random forest (RF), was used to identify the most predictive features of sarcopenia in the whole dataset, considering every possible interaction among variables and taking into account nonlinear relationships that classical models could not evaluate. Then, a logistic regression was performed for comparative purposes. Leading variables of association to sarcopenia overlapped in the two population subsets and included SMI, HGS, FFM of legs and arms, and sex. Using parametric and nonparametric whole-sample analysis to investigate the clinical variables and biological markers most associated with sarcopenia, we found that albumin, CRP, folate, and age ranked high according to RF selection, while sex, folate, and vitamin D were the most relevant according to logistics. Albumin, CRP, vitamin D, and serum folate should not be neglected in screening for sarcopenia in the aging population. Better preventive medicine settings in geriatrics are urgently needed to lessen the impact of sarcopenia on the general health, quality of life, and medical care delivery of the aging population.

Prevalence of sarcopenia in older women and level of agreement between the diagnostic instruments proposed by the European Working Group on Sarcopenia in Older People 2 (EWGSOP2)

BACKGROUND

The European Working Group on Sarcopenia in Older People 2 (EWGSOP2) proposed the use of different diagnostic tools to assess sarcopenia. This study aimed to determine prevalence rates of sarcopenia according to the diagnostic instruments proposed by EWGSOP2 and to assess their level of agreement in older Brazilian women.

METHODS

A cross-sectional study with 161 community-dwelling older Brazilian women. Probable sarcopenia was assessed through Handgrip Strength (HGS) and the 5-times sit-to-stand test (5XSST). In addition to reduced strength, Appendicular Skeletal Muscle Mass (ASM) (obtained by Dual-energy X-ray absorptiometry) and ASM/height² were considered for diagnosis confirmation. Sarcopenia severity was determined by reduced muscle strength and mass and poor functional performance assessed by Gait Speed (GS), Short Physical Performance Battery (SPPB), and Timed Up and Go test (TUG). McNemar's test and Cochran's Q-test were used to compare sarcopenia prevalence. Cohen's Kappa and Fleiss's Kappa tests were used to assess the level of agreement.

RESULTS

The prevalence of probable sarcopenia was significantly different (p < 0.05) when using HGS (12.8%) and 5XSST (40.6%). Regarding confirmed sarcopenia, the prevalence was lower when using ASM/height² than with ASM. Regarding severity, the use of SPPB resulted in a higher prevalence in relation to GS and TUG.

CONCLUSION

There were differences in the prevalence rates of sarcopenia and low agreement between the diagnostic instruments proposed by the EWGSOP2. The findings suggest that these issues must be considered in the discussion on the concept and assessment of sarcopenia, which could ultimately help to better identify patients with this disease in different populations.

Changes of sarcopenia case finding by different Asian Working Group for Sarcopenia in community indwelling middle-aged and old people

Sarcopenia is an emerging issue, but there is no universal consensus regarding its screening and diagnosis, especially regarding the influence of the Asian Working Group for Sarcopenia (AWGS) 2019 new definition on the prevalence of community-dwelling adults. To compare the prevalence of sarcopenia between the 2019 and 2014 definitions, a cross-sectional study including 606 normal nutritional status subjects (203 men/403 women; mean age 63.3 ± 10.0 years) was performed. Sarcopenic parameters, including calf circumference, grip strength, 6-m gait speed, and bioelectrical-impedance-analysis-derived skeletal mass index (SMI), were evaluated. According to the 2019 AWGS definition, the prevalence of possible sarcopenia and sarcopenia among community-dwelling adults was 7.4 and 2.8%, respectively. There were highly consistent findings regarding sarcopenia between the 2019 and 2014 AWGS definitions according to Cohen's kappa coefficient (0.668). However, the prevalence of possible sarcopenia according to 2014 and 2019 AWGS in males increased 7.9%; in contrast, sarcopenia decreased from 7.4 to 3.7% in females (p < 0.001). In conclusion, the AWGS 2019 definition is more convenient for sarcopenia case screening and remains considerably consistent in sarcopenia identification in community-dwelling adults in Taiwan. The discordance of possible sarcopenia and sarcopenia by sex is a concern.

Sarcopenia Is a Cause and Consequence of Metabolic Dysregulation in Aging Humans: Effects of Gut Dysbiosis, Glucose Dysregulation, Diet and Lifestyle

Skeletal muscle mass plays a critical role in a healthy lifespan by helping to regulate glucose homeostasis. As seen in sarcopenia, decreased skeletal muscle mass impairs glucose homeostasis, but it may also be caused by glucose dysregulation. Gut microbiota modulates lipopolysaccharide (LPS) production, short-chain fatty acids (SCFA), and various metabolites that affect the host metabolism, including skeletal muscle tissues, and may have a role in the sarcopenia etiology. Here, we aimed to review the relationship between skeletal muscle mass, glucose homeostasis, and gut microbiota, and the effect of consuming probiotics and prebiotics on the development and pathological consequences of sarcopenia in the aging human population. This review includes discussions about the effects of glucose metabolism and gut microbiota on skeletal muscle mass and sarcopenia and the interaction of dietary intake, physical activity, and gut microbiome to influence sarcopenia through modulating the gut–muscle axis. Emerging evidence suggests that the microbiome can regulate both skeletal muscle mass and function, in part through modulating the metabolisms of short-chain fatty acids and branch-chain amino acids that might act directly on muscle in humans or indirectly through the brain and liver. Dietary factors such as fats, proteins, and indigestible carbohydrates and lifestyle interventions such as exercise, smoking, and alcohol intake can both help and hinder the putative gut–muscle axis. The evidence presented in this review suggests that loss of muscle mass and function are not an inevitable consequence of the aging process, and that dietary and lifestyle interventions may prevent or delay sarcopenia.