Study of the significance of the combination of the fibrinogen-albumin ratio and sarcopenia in predicting the prognosis of laryngeal cancer patients undergoing radical surgery.

OBJECTIVE: This study aims to investigate how the impact of preoperative sarcopenia and inflammatory markers for laryngeal cancer patients and develop a new scoring system to predict their prognosis. MATERIALS AND METHODS: Patients who underwent laryngectomy for laryngeal cancer (LC) from December 2015 to December 2020 at the Second Affiliated Hospital of Fujian Medical University were included. Independent prognostic factors were determined using univariate and multivariate analyses. A new scoring system (SFAR) was established based on FAR and preoperative sarcopenia, and statistically analyzed. RESULTS: 198 cases included in this study that met the admission criteria. Multivariate analysis shown that preoperative sarcopenia, pTNM stage, and FAR were independent prognostic factors for laryngeal cancer. Based on these three indicators, we developed the SFAR scoring system. Multivariate analysis showed that SFAR was an independent predictor of laryngeal cancer (p < 0.001). SFAR was then incorporated into a prognostic model that included T-stage and N-stage, and a column-line graph was generated to accurately predict its survival. CONCLUSION: Systemic inflammation and sarcopenia are significantly associated with postoperative prognosis in laryngeal cancer. A new scoring system (SFAR) had implications for improving the prognosis of patients undergoing surgery for laryngeal cancer.

Association between sarcopenic obesity and osteoarthritis: The potential mediating role of insulin resistance.

BACKGROUND: Sarcopenic obesity (SO) and osteoarthritis (OA) are highly prevalent musculoskeletal conditions that significantly impair health-related quality of life. AIM: This study investigated the association between SO and OA, and explored the potential mediating role of insulin resistance in this relationship. We utilized data from the National Health and Nutrition Examination Survey (NHANES) 1999-2018. METHODS: This cross-sectional analysis employs NHANES data collected from 1999 to 2018, including participants aged 18 years and older. SO was assessed using dual-energy X-ray absorptiometry (DXA) measurements. Insulin resistance was estimated using the triglyceride-glucose (TyG) index. OA status was based on self-reported physician diagnosis. Statistical analyses included weighted logistic regression, restricted cubic spline (RCS) interaction analysis, mediation analysis using structural equation modeling (SEM), and receiver operating characteristic (ROC) curve analysis. Subgroup analyses were conducted based on age, sex, and diabetes status. RESULTS: The sarcopenic obese group demonstrated the highest prevalence of OA (23.4 %), hypertension (47.8 %), and diabetes (12.0 %). Additionally, they exhibited elevated levels of triglycerides, cholesterol, glucose, blood urea nitrogen (BUN), creatinine, and uric acid. Logistic regression revealed significant positive associations between sarcopenic obesity, the TyG index, and OA risk. RCS analysis identified significant non-linear relationships and interactions of the TyG index with age, sex, and diabetes status on OA risk. Mediation analysis indicated that the TyG index mediated approximately 4.9 % of the effect of sarcopenic obesity on OA risk. ROC curve analysis demonstrated moderate diagnostic accuracy for the TyG index (AUC = 0.65), which improved when incorporated into the multivariate model (AUC = 0.78). Subgroup analyses confirmed significant associations between the TyG index and sarcopenic obesity with OA risk across different age, sex, and diabetes status categories. CONCLUSION: Our findings suggest a significant correlation between insulin resistance, as measured by the TyG index, and elevated OA risk in individuals with sarcopenic obesity. Targeting insulin resistance through future research may be a promising avenue to lower OA risk in this population.

Associations between serum cystatin C and fall reports in an Elderly population.

Fall is common in the elderly, and chronic kidney disease is considered a major risk factor. Serum creatinine (Cre) and cystatin C (Cys C) are commonly used biomarkers for renal function, while the ratio of Cre to Cys C, known as the sarcopenia index (SI), provides insights into muscle health. This study investigates the relationships between Cre, Cys C, estimated glomerular filtration rates (eGFR), SI, and self-reported falls using National Health and Nutrition Examination Survey (NHANES) data. We included 4,272 older adults with eGFR > 30mL/min/1.73m2 from NHANES (1999 to 2004) and divided them into the fall and non-fall groups based on the questionnaires. Correlations were assessed using restricted cubic spline, weighted generalized linear regression models. Multi-factor logistic regression analysis identified serum Cys C as significantly associated with falls (all participants: OR 1.16, 95% CI: 1.09 to 1.23, p < 0.001; participants with eGFR > 75 mL/min/1.73m2: OR 1.17, 95% CI: 1.05 to 1.30, p < 0.001,). In contrast, Cre and eGFR were not significant after adjustments; SI showed marginal significance (p = 0.045). Cys C is significantly associated with fall risk in older adults, demonstrating a positive linear relationship with self-reported falls.

Vitamin D combined with whole-body vibration training for the treatment of osteo-sarcopenia: study protocol for a randomized controlled trial.

BACKGROUND: Osteo-sarcopenia (OS) has become a global public health problem and a frontier research problem, as a combination of sarcopenia (SP) and osteoporosis (OP) diseases. The clinical performances include muscle weakness, systemic bone pain, standing difficulty, even falls and fractures, etc., which seriously affect the patient's life and work. The pathological mechanism of the OS may be the abnormal metabolism which disrupts the equilibrium stability of the musculoskeletal system. Therefore, this study combined vitamin D (Vit. D) and whole-body vibration training (WBVT) to intervene in subjects of OS, aiming to evaluate the effectiveness and safety of the diagnosis and treatment protocol and to explore the efficacy mechanism. METHODS: We propose a multicenter, parallel-group clinical trial to evaluate the efficacy and safety of Vit. D combined with WBVT intervention in OS. Subjects who met the inclusion or exclusion criteria and signed the informed consent form would be randomly assigned to the WBVT group, Vit. D group, or WBVT+ Vit. D group. All subjects will be treated for 1 month and followed up after 3 and 6 months. The primary outcomes are lumbar bone mineral density (BMD) and appendicular skeletal muscle mass (ASM) measured by dual-energy X-ray absorptiometry (DXA) and handgrip strength measured by grip strength meter. Secondary outcomes include serum markers of myostatin (MSTN), irisin and bone turnover markers (BTM), SARC-CalF questionnaire, 1-min test question of osteoporosis risk, patient health status (evaluated by the SF-36 health survey), physical performance measurement that includes 5-time chair stand test, 6-m walk, and the short physical performance battery (SPPB). DISCUSSION: If Vit. D combined with WBVT can well relieve OS symptoms without adverse effects, this protocol may be a new treatment strategy for OS. After therapeutic intervention, if the serum marker MSTN/irisin is significant, both have the potential to become sensitive indicators for screening OS effective drugs and treatments, which also indicates that WBVT combined with Vit. D plays a role in improving OS by regulating MSTN/irisin. TRIAL REGISTRATION: Chinese Clinical Trial Registry ChiCTR2400082269 . Registered on March 26, 2024.

The triglyceride glucose related index is an indicator of Sarcopenia.

The triglyceride glucose (TyG) related index, a metric used to evaluate assessing insulin resistance (IR), has received limited attention in its association with sarcopenia. Our study aims to explore the predictive potential of the TyG index for sarcopenia. This study utilized data from the China Health and Retirement Longitudinal Study, a nationally representative, community-based cohort study, including a sample size of 10,537 participants aged 45 years and older. Associations between TyG related index and sacopenia was explored using multivariate logistic regression. Analysis of the predictive value of TyG related index for sarcopenia using receiver-operating characteristic curve (ROC). We evaluated the correlation between the TyG related index and the risk of sarcopenia using Cox proportional hazards models. Additionally, we utilized restricted cubic spline (RCS) regression analyses to explore the connections between the TyG-related index and sarcopenia. Logistic regression analysis showed an association between TyG (OR 0.961[0.955,0.968], P < 0.001), TyG-body mass index (TyG-BMI) (OR 0.872[0.867,0.878], P < 0.001), TyG- waist circumference (TyG-WC) (OR 0.896[0.890,0.902], P < 0.001) and sarcopenia. The results of the ROC analysis indicated that the area under the curve values for TyG, TyG-BMI, and TyG-WC were 0.659, 0.903, and 0.819, respectively. Compared to those without sarcopenia, patients with sarcopenia had a 37.7% (HR 0.623[0.502,0.774], P < 0.001), 4.8% (HR 0.952[0.947,0.958], P < 0.001), and 0.4% (HR 0.996[0.995,0.996], P < 0.001) lower risk with increasing TyG, TyG-BMI, and TyG-WC, respectively. RCS results show nonlinear relationship between TyG-BMI (P < 0.001) and TyG-WC (P < 0.001) and risk of sarcopenia. We observed a correlation between the TyG-related index and sarcopenia, with the TyG-BMI index demonstrating strong predictive capability for sarcopenia.

Association of triglyceride-glucose index with sarcopenia: NHANES 2011-2014.

Background: A newly developed technique, the Triglyceride-glucose (TyG) index, supplies a more straightforward method to identify IR than the HOMA-IR (Homeostasis Model Assessment of Insulin Resistance). Yet no methodical analysis has looked into the link involving the TyG index and low muscle mass (LMM), low muscle strength (LMS), and sarcopenia within the US. Thus, this study intended to find any connection concerning the TyG index and LMM, LMS, and sarcopenia. Methods: Between 2011 to 2014, data from the NHANES were used to conduct a nationally representative study involving 2,504 participants. LMM, LMS, and sarcopenia were the outcome variables. Moreover, this positive correlation persists irrespective of age and gender. Results: The TyG index revealed a significant correlation with the prevalence of developing LMM (OR = 1.63(1.26-2.11), p=0.001), LMS (OR = 1.61(1.36-1.91), p<0.001) and sarcopenia (OR = 1.59 (1.23-2.07), p<0.001), after correcting for all variables. Utilizing smooth curve fitting alongside two-piecewise linear regression models, an inverted U-shaped correlation between the TyG index and the prevalence of LMM, LMS, and sarcopenia. Finally, subgroup analysis revealed that the association between the TyG index and LMM, LMS, and sarcopenia was particularly evident in all gender, age subgroups, and individuals with a normal BMI of 25. Conclusion: Sarcopenia and the TyG index reveal an essential positive link. It highlights the potential utility of the TyG index as a screening tool for identifying individuals at risk of sarcopenia earlier.

Impact of C-Reactive Protein and Liver Frailty Index on Sarcopenia and Poor Outcome in Liver Transplant Patients.

BACKGROUND: Sarcopenia is a complication that occurs after liver transplantation (LT), and it is a poor prognostic factor. METHODS: A total of 23 healthy controls and 131 LT patients (18 - 76 weeks of age) were enrolled in the study. Pa-tients were grouped according to the North American Working Group on Sarcopenia in Liver Transplantation by performing pre- and post-transplant CT scans of the third lumbar (L3). The serum C-reactive protein (CRP) was analyzed and the liver frailty index (LFI) was assessed. Their associations with postoperative sarcopenia, skeletal muscle index (SMI), and poor outcomes were examined. RESULTS: Before LT, the serum CRP was increased in patients with LT, compared with the healthy subjects, and had the highest levels in patients with sarcopenia. There were seventy-nine patients with sarcopenia after LT, including 48 who had been diagnosed with sarcopenia preoperatively and 31 who had a new onset of sarcopenia after LT. There was a moderate-strength negative correlation between the preoperative and postoperative rates of change in CRP and L3 SMI. Patients assessed as frail preoperatively (LFI ≥ 4.5) were associated with postoperative sarcopenia, and 19 of the new postoperative sarcopenia cases occurred in patients assessed as frail preoperatively. The serum CRP levels and LFI were significantly higher in patients who experienced a prolonged hospitalization and early infections postoperatively than in patients without significant adverse events. CRP (post-LT) > 2.575 pg/mL (OR = 1.16, 95% CI: 1.06 - 2.39, p = 0.026) as well as frailty (OR = 1.36, 95% CI: 1.20 - 2.60, p = 0.001) were independent predictors of sarcopenia after LT in patients. CONCLUSIONS: Serum CRP levels and LFI may be effective for an early detection of sarcopenia in patients with LT.

The relationship between sarcopenia and related bioindicators and changes after intensive lifestyle intervention in elderly East-China populations.

BACKGROUND: As populations live longer, there is a progressive increase in chronic degenerative diseases, particularly those related to the musculoskeletal system. Sarcopenia is characterized by loss of skeletal muscle mass, muscle strength, and loss of physical function. It is a common disease in older adults associated with various adverse health outcomes. There is a lack of bioindicators to screen for sarcopenia. Albumin and lymphocyte counts are commonly used to assess the degree of malnutrition, and blood routine, lipids, and thyroid function are relatively easy to obtain as part of a routine physical examination. Therefore, finding blood markers that can screen for sarcopenia is essential. Our primary aim was to explore whether the bioindicators of body composition, lymphocytes, albumin, lipids, and thyroid hormones are associated with sarcopenia, and a secondary aim was to investigate changes in these indicators after an intensive lifestyle intervention preliminarily. METHODS: 60 subjects were selected from Runda and Bailian community health centers in Suzhou, China. They underwent body composition analysis and tested lymphocyte, albumin, lipid, and thyroid hormone levels. The 30 sarcopenia subjects underwent a 3-month intensive lifestyle intervention program. At the end of the intervention, we rechecked the bioindicators. Statistical analyses were performed in IBM SPSS v26.0. RESULTS: The blood indices of sarcopenia subjects were generally lower in albumin, non-high-density lipoprotein cholesterol (non-HDL-C), and free triiodothyronine (FT3). Body mass index (BMI)(r = 0.6266, p < 0.0001), fat-free mass (r = 0.8110, p < 0.0001), basal metabolism (r = 0.7782, p < 0.0001), and fat mass (r = 0.3916, p = 0.0020) were positively correlated with appendicular skeletal muscle index (ASMI). Higher BMI and FT3 were associated with lower odds of sarcopenia, while higher fat mass was associated with higher odds of sarcopenia. After a 3-month intensive intervention, sarcopenia subjects had a significant increase in BMI, ASMI, lymphocyte, and albumin levels, and an increase in FT3, but with a non-significant difference (p = 0.342). CONCLUSIONS: Low BMI, FT3, and high fat mass were associated with sarcopenia. Intensive lifestyle intervention can significantly improve ASMI, BMI, lymphocytes, albumin, and FT3 in sarcopenia subjects, which is favorable for delaying the progression of sarcopenia. TRIAL REGISTRATION: This study was retrospectively registered on ClinicalTrials.gov, registration number NCT06128577, date of registration: 07/11/2023.

Association of atherogenic index of plasma and triglyceride glucose-body mass index and sarcopenia in adults from 20 to 59: a cross-sectional study.

Background: The relationship between atherogenic index of plasma (AIP) and triglyceride glucose-body mass index (TyG-BMI) and sarcopenia has not been studied in the United States (US) population. Methods: This research included 4,835 people from the National Health and Nutrition Examination Survey (NHANES) conducted between 2011 and 2018. The relationship between sarcopenia and TyG-BMI, as well as the AIP index, was examined through the utilization of restricted cubic spline (RCS) analysis, subgroup analysis, and multivariate logistic regression analysis. Diagnostic value of AIP and TyG-BMI for sarcopenia was compared by receiver operating characteristic (ROC) curves. Results: In this research, 428 people with sarcopenia were identified among the 4,835 subjects that were included in the experiment. AIP and sarcopenia were positively associated with an odds ratio (OR) of 1.58 and a 95% confidence interval (CI) of (1.07, 2.34) on fully adjusted multivariate logistic regression analysis. Similarly, TyG-BMI and sarcopenia were positively associated with an OR of 8.83 and a 95% CI of (5.46, 14.26). AIP and sarcopenia had a non-linear positive connection (P-value<0.001, P-Nonlinear=0.010), while TyG-BMI and sarcopenia had a linear positive correlation (P-value<0.001, P-Nonlinear=0.064), according to RCS analysis. Subgroup analyses showed a significant interaction between TyG-BMI and sarcopenia due to gender (P = 0.023). ROC curves showed that TyG-BMI (AUC:0.738, 95% CI: 0.714 - 0.761) was more useful than AIP (AUC:0.648, 95% CI: 0.622 - 0.673) in diagnosing sarcopenia. Conclusion: In US adults aged 20-59 years, our study revealed a correlation between elevated AIP and TyG-BMI levels and heightened sarcopenia risk. Moreover, TyG-BMI has better diagnostic validity than AIP.

High-density lipoprotein cholesterol level and risk of muscle strength decline and sarcopenia in older adults.

BACKGROUND: Recent studies have demonstrated that very high high-density lipoprotein cholesterol (HDL-C) level was paradoxically linked with higher risk of cardiovascular mortality, all-cause mortality, and several age-related diseases. However, whether very high HDL-C level is associated with a higher risk of sarcopenia in older adults remains unclear. We aimed to investigate the association between HDL-C level and the risk of developing sarcopenia and low grip strength over time in older adults. METHODS: Participants were from the ongoing China Health and Retirement Longitudinal Study (CHARLS), which includes a nationally representative sample of adults aged ≥45 years and was performed from 2011 to 2020 with follow-ups every two to three years. The current study included 4031 participants aged ≥60 years. Muscle health-related data were collected in waves 2011, 2013, and 2015. Based on HDL-C level at baseline, participants were categorized into five groups: <35 mg/dl, 35-40 mg/dl, 40-60 mg/dl, 60-70 mg/dl and >70 mg/dl. The main outcomes were incident sarcopenia and incident low grip strength over follow-up. Low grip strength and sarcopenia were defined according to the 2019 Consensus by the Asian Working Group for Sarcopenia. Cox proportional-hazard regression was performed to investigate the association between HDL-C level and the risk of developing sarcopenia and low grip strength in older adults. RESULTS: The mean age of study sample was 67.3 (SD 6.1) years, and 49.6% were male. During an average 3.7-year follow-up, 409 (10.1%) participants developed sarcopenia and 771 (21.1%) developed low grip strength. Non-linear association was observed between HDL-C level and the hazard of developing sarcopenia and low grip strength. The multivariable model showed that compared to the reference group (40-60 mg/dl), older adults with very high HDL-C level (>70 mg/dl) had a significantly higher risk of developing sarcopenia (HR 1.69, 95% CI 1.28-2.23) and low grip strength (HR 1.23 95% CI 1.00-1.51). Stratified analyses by sex revealed similar association. CONCLUSIONS: We present the first longitudinal evidence that very high HDL-C level was associated with a significantly higher risk of muscle strength decline and developing sarcopenia in older adults. It is essential to monitor the muscle health of older adults with very high HDL-C level in clinical practice.

Circulating small non-coding RNA profiling for identification of older adults with low muscle strength and physical performance: A preliminary study.

BACKGROUND: Small non-coding RNAs (ncRNAs) have recently emerged as potential biomarkers of sarcopenia. However, previous studies have rarely explored the association of small ncRNAs with sarcopenic components, especially muscle strength and physical performance. We aimed to examine circulating small ncRNA profiles to detect low muscle strength and physical performance in older adults. METHODS: Ninety-eight older adults were randomly selected from Korean Frailty and Aging Cohort Study and classified into the "Normal," "Low muscle strength (MS) only," "Low physical performance (PP) only," and "Low MS and PP" groups by Asian Working Group for Sarcopenia 2019 criteria. We used high-throughput sequencing to delineate small ncRNA profiles in plasma. Differentially expressed small ncRNAs were analyzed to reveal distinct patterns based on muscle strength and physical performance status. RESULTS: In "Low MS and PP" group, 119 miRNAs, 86 piRNAs, 92 snoRNAs, 106 snRNAs, and 15 tRNAs were differentially expressed compared to "Normal" group (p < 0.05). After Benjamini-Hochberg adjustment, 39 miRNAs, 2 piRNAs, 75 snoRNAs, 48 snRNAs, and 15 tRNAs showed differential expression in "Low MS and PP" group compared to than "Normal" group (adjusted p < 0.05). No significant differences were observed in comparisons between the other groups (adjusted p > 0.05). CONCLUSION: The expression of circulating small ncRNAs were comprehensively characterized, revealing distinct signatures in older adults with both low muscle strength and physical performance compared to normal individuals. Although preliminary, this characterization can advance small ncRNA research on age-related declines in muscle strength and physical performance by providing foundational data for further investigation.

Causal roles of circulating cytokines in sarcopenia-related traits: a Mendelian randomization study.

Background: Epidemiological and experimental evidence suggests that chronic inflammation plays an important role in the onset and progression of sarcopenia. However, there is inconsistent data on the inflammatory cytokines involved in the pathogenesis of sarcopenia. Therefore, we performed a two-sample Mendelian randomization (MR) analysis to explore the causal relationship between circulating cytokines and sarcopenia-related traits. Methods: The MR analysis utilized genetic data from genome-wide association study that included genetic variations in 41 circulating cytokines and genetic variant data for appendicular lean mass (ALM), hand grip strength, and usual walking pace. Causal associations were primarily explored using the inverse variance-weighted (IVW) method, supplemented by MR-Egger, simple mode, weighted median, and weighted mode analyses. Additionally, sensitivity analyses were also performed to ensure the reliability and stability of the results. Results: Three cytokines [hepatocyte growth factor (HGF), interferon gamma-induced protein 10 (IP-10), and macrophage colony-stimulating factor (M-CSF)] were positively associated with ALM (ß: 0.0221, 95% confidence interval (CI): 0.0071, 0.0372, P= 0.0039 for HGF; ß: 0.0096, 95%CI: 4e-04, 0.0189, P= 0.0419 for IP-10; and ß: 0.0100, 95%CI: 0.0035, 0.0165, P= 0.0025 for M-CSF). Conversely, higher levels of interleukin-7 (IL-7), monocyte chemotactic protein 3 (MCP-3), and regulated on activation, normal T cell expressed and secreted (RANTES) were associated with decreased hand grip strength (ß: -0.0071, 95%CI: -0.0127, -0.0014, P= 0.0140 for IL-7; ß: -0.0064, 95%CI: -0.0123, -6e-04, P= 0.0313 for MCP-3; and ß: -0.0082, 95%CI: -0.0164, -1e-04, P= 0.0480 for RANTES). Similarly, interleukin 1 receptor antagonist (IL-1RA) was negatively correlated with usual walking pace (ß: -0.0104, 95%CI: -0.0195, -0.0013, P= 0.0254). Sensitivity analysis confirmed the robustness of these findings. Conclusions: Our study provides additional insights into the pivotal role of specific inflammatory cytokines in the pathogenesis of sarcopenia. Further research is required to determine whether these cytokines can be used as targets for the prevention and treatment of sarcopenia.

The association between non­high­density lipoprotein cholesterol to high­density lipoprotein cholesterol ratio (NHHR) and low muscle mass in adults aged 20-59: a population-based study in the United States.

BACKGROUND: The ratio between non-high-density lipoprotein cholesterol and high-density lipoprotein cholesterol (NHHR) is a reliable marker for assessing the risk linked to lipid metabolism disorders. Sarcopenia, characterized by age-related loss of muscle mass and strength/function, includes the assessment of muscle mass, muscle strength, and muscle-specific strength. However, research into NHHR's relationship with low muscle mass risk remains unexplored. METHODS: Our study utilized a cross-sectional approach, examining data derived from the National Health and Nutrition Examination Survey (NHANES) from 2011 to 2018. Through multivariable linear and logistic regression, we investigated the relationships of the NHHR with muscle mass and low muscle mass. We visualized the results using smoothing curves and assessed threshold effects. We also performed various subgroup and sensitivity analyses. RESULTS: This research encompassed 9,012 participants and demonstrated significant nonlinear associations between NHHR and ALMBMI or low muscle mass risk in a generalized additive model (GAM), pinpointing critical NHHR values (3.328 and 3.367) where changes in NHHR significantly impacted ALMBMI and low muscle mass risk. CONCLUSIONS: The NHHR demonstrates a significant association with an increased risk of low muscle mass among middle-aged Americans. This ratio has potential as a predictive marker for low muscle mass. Further exploration of NHHR is expected to aid in advancing preventive and therapeutic measures for this condition.

The relationship between serum lipid with sarcopenia: Results from the NHANES 2011-2018 and bidirectional Mendelian randomization study.

BACKGROUND: The relationship between serum lipids and sarcopenia remains unclear due to conflicting results in previous studies. OBJECTIVE: To explore the associations and potential causality between serum lipids, including high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), triglycerides (TG), and total cholesterol (TC), and sarcopenia. METHODS: Data from the National Health and Nutrition Examination Survey (NHANES) were analysed using multivariable regression and restricted cubic splines (RCSs) to assess the associations between serum lipids and sarcopenia. Bidirectional Mendelian randomization (MR) was employed to investigate the causal relationships with sarcopenia-related traits such as appendicular lean mass (ALM), hand grip strength, and usual walking pace. RESULTS: Serum HDL-C and TG levels were inversely associated with ALMBMI, with each 1-unit increase linked to a 0.13 % and 1.32 % decrease, respectively. Elevated TG, but not HDL-C, LDL-C, or TC levels, was significantly associated with an increased risk of sarcopenia (P for trend = 0.001). RCS analysis revealed a log-shaped dose-response relationship between TG and sarcopenia risk (P overall <0.001, P non-linear <0.001), with a cutoff value of 92.75 mg/dL. Genetically predicted HDL-C, LDL-C, and TG were associated with ALM. Conversely, ALM showed an inverse causal relationship with all four serum lipids. Additionally, genetically predicted usual walking pace influenced HDL-C and TG levels (P < 0.001). CONCLUSION: The study reveals a nonlinear association between TG levels and sarcopenia risk, and a bidirectional association between lipid profiles and muscle mass, underscoring the need for further research to elucidate these mechanisms.

Serum creatinine and serum cystatin C as an index of muscle mass in adults.

PURPOSE OF REVIEW: Serum creatinine reflects both muscle mass and kidney function. Serum cystatin C has recently been recommended as an additional marker for estimating kidney function, and use of both markers together may provide an index of muscle mass. This review aims to describe the biological basis for and recent research examining the relationship of these markers to muscle mass in a range of adult populations and settings. RECENT FINDINGS: This review identified 67 studies, 50 of which had direct measures of muscle mass, and almost all found relationships between serum creatinine and cystatin C and muscle mass and related outcomes. Most studies have been performed in older adults, but similar associations were found in general populations as well as in subgroups with cancer, chronic kidney disease (CKD), and other morbid conditions. Creatinine to cystatin C ratio was the measure examined the most often, but other measures showed similar associations across studies. SUMMARY: Measures of serum creatinine and cystatin C together can be an index of muscle mass. They are simple and reliable measures that can be used in clinical practice and research. Further study is needed to determine actionable threshold values for each measure and clinical utility of testing and intervention.

Association of serum iron metabolism with muscle mass and frailty in older adults: A cross-sectional study of community-dwelling older adults.

This study aimed to explore the correlation between serum ferritin and additional biomarkers associated with iron metabolism, as well as their connection to muscle atrophy and frailty in the community-dwelling middle-aged and elderly population. The study included 110 middle-aged and elderly participants. Participants were categorized into an iron accumulation group (31 cases) and a normal iron group (79 cases) based on the standard ferritin values for men and women. Based on the criteria of the Asian Working Group on Muscular Dystrophy, participants were classified into a sarcopenia group (31 cases) and a non-sarcopenia group (79 cases). Using the Fried frailty syndrome criteria, participants were categorized into non-frailty (7 cases), pre-frailty (50 cases), and frailty (53 cases) groups. We employed multiple linear regression, binary logistic regression, partial correlation analysis, and ordinal logistic regression to assess the associations between iron metabolism indices and the presence of muscle atrophy and frailty. Compared with the normal iron group, the iron overload group had significantly higher ferritin, weight loss, fatigue, slow gait, and frailty scores (P < .05). Among the 3 models we set, ferritin was not significantly correlated with muscle mass in models 1 and 3 (P > .05), ferritin was positively correlated with muscle mass in model 2 (Pmodel2 = .048), but Transferrin saturation was positively correlated with muscle mass in all 3 models (Pmodel1 = .047, Pmodel2 = .026, Pmodel3 = .024). Ferritin, body mass index and iron overload were the influencing factors of sarcopenia (Pferritin = .027, PBMI < .001, Piron overload = .028). Ferritin was positively correlated with weight loss, fatigue, slow gait, frailty score, and frailty grade (P < .05). Age, gender and ferritin were the influencing factors of frailty classification (P < .05). Disrupted iron metabolism can lead to decreased muscle mass and function among the middle-aged and elderly, increasing frailty risk. It's crucial to prioritize community-based frailty screening and prevention, focusing on iron utilization as well as storage, since accelerating the body's iron metabolism cycle might influence muscle health more significantly than iron reserves.

Novel metabolic and lipidomic biomarkers of sarcopenia.

BACKGROUND: The pathophysiology of sarcopenia is complex and multifactorial and has not been fully elucidated. The impact of resistance training and nutritional support (RTNS) on metabolomics and lipodomics in older adults with sarcopenia remains uncertain. This study aimed to explore potential biomarkers of sarcopenia and clinical indicators of RTNS in older sarcopenic adults. METHODS: Older individuals diagnosed with sarcopenia through routine health checkups at a community hospital were recruited for a 12-week randomized controlled trial focusing on RTNS. Plasma metabolomic and lipidomic profiles of 45 patients with sarcopenia and 47 matched controls were analysed using 1H-nuclear magnetic resonance (1H-NMR) and liquid chromatography-mass spectrometer (LC-MS). RESULTS: At baseline, the patient and control groups had similar age, sex, and height distribution. The patient group had significantly lower weight, BMI, grip strength, gait speed, skeletal muscle index, lean mass of both the upper and lower limbs, and lower limb bone mass. There was a significant difference in 12 metabolites between the control and patient groups. They are isoleucine (patient/control fold change [FC] = 0.86 ± 0.04, P = 0.0005), carnitine (FC = 1.05 ± 0.01, P = 0.0110), 1-methylhistamine/3-methylhistamine (FC = 1.24 ± 0.14, P = 0.0039), creatinine (FC = 0.71 ± 0.04, P < 0.0001), carnosine (FC = 0.71 ± 0.04, P = 0.0007), ureidopropionic acid (FC = 0.61 ± 0.10, P = 0.0107), uric acid (FC = 0.88 ± 0.03, P = 0.0083), PC (18:2/20:0) (FC = 0.69 ± 0.03, P = 0.0010), PC (20:2/18:0) (FC = 0.70 ± 0.06, P = 0.0014), PC (18:1/20:1) (FC = 0.74 ± 0.05, P = 0.0015), PI 32:1 (FC = 4.72 ± 0.17, P = 0.0006), and PI 34:3 (FC = 1.88 ± 0.13, P = 0.0003). Among them, carnitine, 1-methylhistamine/3-methylhistamine, creatinine, ureidopropionic acid, uric acid, PI 32:1, and PI 34:3 were first identified. Notably, PI 32:1 had highest diagnostic accuracy (0.938) for sarcopenia. 1-Methylhistamine/3-methylhistamine, carnosine, PC (18:2/20:0), PI 32:1, and PI 34:3 levels were not different from the control group after RTNS. These metabolites are involved in amino acid metabolism, lipid metabolism, and the PI3K-AKT/mTOR signalling pathway through the ingenuity pathway analysis. CONCLUSIONS: These findings provide information on metabolic changes, lipid perturbations, and the role of RTNS in patients with sarcopenia. They reveal new insights into its pathological mechanisms and potential therapies.

Severe trauma leads to sustained muscle loss, induced frailty, and distinct temporal changes in myokine and chemokine profiles of older patients.

INTRODUCTION: Sarcopenia is a known risk factor for adverse outcomes across multiple disease states, including severe trauma. Factors such as age, hyperinflammation, prolonged immobilization, and critical illness may not only exacerbate progression of this disease but may also contribute to the development of induced sarcopenia, or sarcopenia secondary to hospitalization. This study seeks to (1) determine the effects of severe traumatic injury on changes in skeletal muscle mass in older adults; (2) test whether changes in skeletal muscle mass are associated with clinical frailty, physical performance, and health-related quality of life; and (3) examine trauma-induced frailty and temporal changes in myokine and chemokine profiles. METHODS: A prospective, longitudinal cohort study of 47 critically ill, older (≥45 years) adults presenting after severe blunt trauma was conducted. Repeated measures of computed tomography-based skeletal muscle index, frailty, and quality of life were obtained in addition to selected plasma biomarkers over 6 months. RESULTS: Severe trauma was associated with significant losses in skeletal muscle mass and increased incidence of sarcopenia from 36% at baseline to 60% at 6 months. Severe trauma also was associated with a transient worsening of induced frailty and reduced quality of life irrespective of sarcopenia status, which returned to baseline by 6 months after injury. Admission biomarker levels were not associated with skeletal muscle index at the time points studied but demonstrated distinct temporal changes across our entire cohort. CONCLUSIONS: Severe blunt trauma in older adults is associated with increased incidence of induced sarcopenia and reversible induced frailty. Despite muscle wasting, functional decline is transient, with a return to baseline by 6 months, suggesting a need for holistic definitions of sarcopenia and further investigation into long-term functional outcomes in this population.

Impact of Serum Creatinine- and Cystatin C-Based Sarcopenia Index on Renal Outcomes in Non-Dialysis-Dependent Chronic Kidney Disease Patients: Results From the KNOW-CKD Study.

OBJECTIVE: To evaluate the impact of the serum creatinine- and cystatin C-based new sarcopenia index (SI) on renal outcomes in non-dialysis-dependent patients with chronic kidney disease (CKD). METHODS: In this observational Korean Cohort Study for Outcome in Patients With CKD (KNOW-CKD), 1957 patients with CKD stage 1 to stage 4 were analyzed from 2011 to 2019. Men and women were separately assigned to quartile groups according to their SI. The primary outcome was a composite renal outcome consisting of 50% reduction in estimated glomerular filtration rate or end-stage kidney disease. With use of Fine and Gray subdistribution hazard models, the association between the SI and the primary outcome was analyzed. RESULTS: During a median follow-up of 6.0 (4.2 to 7.7) years, the primary composite renal outcome occurred in 528 (28.6%) patients within a median of 3.0 (1.8 to 5.0) years. In unadjusted and adjusted models, lower SI groups had a poor primary outcome compared with the highest group (quartile 4). The hazard ratios for quartiles 1, 2, and 3 compared with quartile 4 in the fully adjusted model were 4.47 (95% CI, 3.05 to 6.56; P<.001), 3.08 (95% CI, 2.13 to 4.48; P<.001), and 2.09 (95% CI, 1.45 to 3.01; P<.001), respectively. Restricted cubic spline regression analyses found a relatively inverse linear relationship between the SI and the composite renal outcome. CONCLUSION: The new SI is an independent predictor of renal outcomes. A low SI is associated with poor renal outcome.

Association of interleukin-6 with sarcopenia and its components in older adults: a systematic review and meta-analysis of cross-sectional studies.

BACKGROUND: Observational studies have documented increased serum IL-6 levels in elderly individuals afflicted with sarcopenia. Nevertheless, the relationship between serum IL-6 concentrations and sarcopenia prevalence in the aging population is yet to be defined. METHODS: We executed a systematic review and meta-analysis of cross-sectional studies that scrutinized serum IL-6 levels in older adults with and without sarcopenia. Relevant studies were sourced from PubMed, Scopus, Embase, Cochrane Library, and Web of Science from inception until 10 September 2023. The standard mean differences (SMDs) in serum IL-6 levels between studies were synthesized using a random-effects model. To examine the influence of demographic and clinical factors on these outcomes, we performed subgroup analyses and meta-regression, focusing on variables such as sex, age, and body mass index (BMI). We also assessed the relationship between serum IL-6 levels and the defining components of sarcopenia: muscle mass, muscle strength, and physical performance. We used Fisher's Z transformation to standardize the interpretation of effect sizes from these relationships. The transformed values were then converted to summary correlation coefficients (r) for a clear and unified summary of the results. RESULTS: We included twenty-one cross-sectional studies involving 3,902 participants. Meta-analysis revealed significantly elevated serum IL-6 levels in older adults with sarcopenia compared with those without sarcopenia (SMD = 0.31; 95% CI 0.18, 0.44). The difference was highly pronounced in the subgroups of male and those with female percentage below 50% or a mean BMI below 24 kg/m2. Serum IL-6 levels were inversely correlated with muscle mass (summary r = -0.18; 95% CI -0.30, -0.06), but not with handgrip strength (summary r = -0.10; 95%CI: -0.25, 0.05) or gait speed (summary r = -0.09; 95%CI: -0.24, 0.07). CONCLUSIONS: This meta-analysis establishes a link between increased serum IL-6 levels and sarcopenia in the elderly, particularly in relation to decreased muscle mass.

Several studies have demonstrated elevated serum IL-6 levels in elderly individuals with sarcopenia, while the relationship between serum IL-6 levels and sarcopenia remains unclear.This is a systematic review and meta-analysis of 21 cross-sectional studies for the relationship between serum IL-6 levels and sarcopenia.Elevated serum IL-6 levels appear to be associated with sarcopenia in older adults, especially in relation to reduced muscle mass.