Sarcopenia in nonalcoholic fatty liver disease and all-cause and cause-specific mortality in the United States

Association of ultrasound signs of sarcopenia with serum ferritin levels and hepatic indices like NFS and FIB-4 in NAFLD patients

INTRODUCTION

Non-alcoholic fatty liver disease is one of the most common chronic diseases all around the world, which significantly correlates with metabolic disorders and inflammatory cycles. Sarcopenia is a decrease in the mass of skeletal muscles interacting with factors such as inflammatory processes and chronic diseases. It can also lead to the aggravation of chronic diseases.

METHOD

The study population was randomly selected and entered into the research based on exclusion and inclusion criteria. Non-alcoholic fatty liver disease was confirmed in all members of the study population by ultrasound. Patients' serum ferritin level was assessed, and their NFS and Fib 4 scores were calculated. Sarcopenia was diagnosed by measuring the thickness of the rectus femoris by ultrasonography. The correlation between these variables was evaluated and analyzed by statistical software.

RESULTS

According to statistical analysis, there is a significant association between the serum ferritin level and sarcopenia (P-value < 0.001). Besides, there is a significant association between NFS, Fib4, and sarcopenia (P-value = 0.024, 0.000).

CONCLUSION

This research's results reflect the correlation between serum ferritin and sarcopenia; however, it cannot conclude a cause-and-effect relationship between these variables.

Metabolic dysfunction-associated steatotic liver disease (MASLD): Exploring systemic impacts and innovative therapies

Metabolic dysfunction-associated steatotic liver disease (MASLD), which includes the inflammatory subtype metabolic dysfunction-associated steatohepatitis, is a prominent cause of chronic liver disease with systemic effects. Insulin resistance, obesity, and dyslipidaemia produce MASLD in over 30 % of adults. It is a global health issue. From MASLD to MASH, hepatic inflammation and fibrosis grow, leading to cirrhosis, hepatocellular cancer, and extrahepatic complications such CVD, CKD, and sarcopenia. Effects of MASLD to MASH are mediated through mechanisms that include inflammation, oxidative stress, dysbiosis, and predisposition through genetic makeup. Advances in diagnostic nomenclature in the past few years have moved the emphasis away from NAFLD to MASLD, focusing on the metabolic etiology and away from the stigma of an alcoholic-related condition. Epidemiological data show a large geographical variability and increasing prevalence in younger populations, particularly in regions with high carbohydrate-rich diets and central adiposity. Lifestyle modification is considered as the main management of MASLD currently. This may include dietary intervention, exercise, and weight loss management. Pharmaceutical management is primarily aimed at metabolic dysfunction with promising findings for GLP-1 receptor agonists, pioglitazone and SGLT-2 inhibitors, which can correct both hepatic and systemic outcome. However, it still depends on well-integrated multidisciplinary care models by considering complex relationships between MASLD and its effects on extrahepatic organs. Determining complications at an early stage; developing precision medicine strategies; exploring new therapeutic targets will represent crucial factors in improving their outcomes. This review discuss the systemic nature of MASLD and calls for multiple collaborations to reduce its far-reaching health impacts and our quest for understanding its pathological mechanisms. Thus, collective efforts that are required to address MASLD are under the public health, clinical care, and research angles toward effectively containing its rapidly increasing burden.

A cross-sectional study of risk factors associated with sarcopenia in patients with metabolic dysfunction-associated steatotic liver disease

Background

Metabolic dysfunction-associated steatotic liver disease (MASLD) is a chronic liver disease linked to several adverse health consequences that include metabolic disturbances affecting skeletal muscle. Sarcopenia, characterized by skeletal muscle loss, is commonly observed in individuals with MASLD. Our study aimed to identify modifiable lifestyle factors associated with sarcopenia in patients with MASLD.

Methods

This study was a cross-sectional study that was conducted in three clinics in Nablus. A total of 162 adults diagnosed with MASLD were recruited for the study. The patients were interviewed and instructed to provide the necessary information, such as sociodemographic factors, medical and surgical history, lifestyle information, MASLD-related data, and nutritional and functional status. Sarcopenia was defined using the Foundation for the National Institutes of Health (FNIH) criteria, which includes the weight-adjusted skeletal muscle index (wSMI) with the cut-off scores (male subjects: 35.7% and female subjects: 30.7%). Statistical analysis was conducted using SPSS v.21. A chi-squared or independent samples t-test was utilized to identify the factors linked to sarcopenia in the study sample.

Results

Our data found that 44% of MASLD patients had sarcopenia. This condition was significantly associated with female gender (p < 0.0001), older age (p < 0.0001), presence of chronic diseases (p < 0.035), and medication use (p < 0.05). Regarding nutritional factors, sarcopenia had a significant association with obesity, a higher body fat percentage, a high waist-to-hip ratio, a low mid-upper arm circumference, and a reduced calf circumference (p < 0.001). Sarcopenic individuals often exhibit reduced handgrip strength. Lifestyle factors such as a history of smoking and the type of smoking were found to be positively associated with sarcopenia (p < 0.0001).

Conclusion

Sarcopenia was prevalent in the study population and was linked to modifiable risk factors that can be managed to reduce its progression. Future research using different study designs, such as longitudinal design, is recommended to identify the determinants of sarcopenia. Intervention studies are also required to improve the nutritional and functional status of MASLD patients.

Impact of steatotic liver disease subtypes, sarcopenia, and fibrosis on all-cause and cause-specific mortality: a 15.7-year cohort study

BACKGROUND

Steatotic liver disease (SLD) was a newly proposed disease category derived from metabolic dysfunction-associated fatty liver disease (MAFLD). MAFLD and sarcopenia were independent risk factors for mortality. We aimed to evaluate the impacts of SLD subtypes, MAFLD, and sarcopenia on mortality.

METHODS

A total of 6543 subjects were identified from the National Health and Nutrition Examination Survey 1999-2006 with the latest Linked Mortality file. Hepatic steatosis, advanced fibrosis, and sarcopenia were determined by the laboratory- and anthropometry- based fatty liver index and fibrosis-4 index, and dual-energy X-ray absorptiometry-based appendicular skeletal muscle mass index, respectively. Associations of SLD subtypes, MAFLD, and sarcopenia with mortality were estimated using the weighted Cox proportional hazards model.

RESULTS

During a mean follow-up time of 15.7 years, 1567 (16.7%) deaths occurred including 494 (4.9%) deaths from cardiovascular diseases and 372 (4.1%) from cancer. The all-cause mortality rates of MAFLD, metabolic dysfunction-associated steatotic liver disease (MASLD), metabolic dysfunction and alcohol-associated liver disease (MetALD), other aetiology SLD, MASLD without sarcopenia, and MASLD with sarcopenia were 21.0%, 19.8%, 30.2%, 30.9%, 19.2%, and 75.5%, respectively. MAFLD increased the risk of all-cause mortality (hazard ratio [HR] 1.26, 95% confidence interval [CI] 1.00-1.59). MASLD predicted all-cause mortality (HR 1.17, 95% CI 1.03-1.33) but this prediction became insignificant after adjustment for metabolic risks. In contrast, MetALD and other aetiology SLD were significantly associated with all-cause mortality (HR 1.83, 95% CI 1.21-2.76; HR 2.50, 95% CI 1.82-3.44, respectively), predominantly associated with cancer-specific mortality (HR 2.42, 95% CI 1.23-4.74; HR 2.49, 95% CI 1.05-5.90, respectively). MASLD with sarcopenia increased the risk of all-cause mortality by almost twice (HR 2.19, 95% CI 1.37-3.49) and further coexisting advanced fibrosis additively increased mortality (HR 3.41, 95% CI 1.92-6.05).

CONCLUSION

SLD definition identified a more homogeneous group with metabolically hepatic steatosis at higher risks of mortality. MASLD or MASLD-related advanced fibrosis and sarcopenia additively increased mortality.

Muscle Strength and Cardiovascular Health in MASLD: A Prospective Study

Background and Objectives: The pathogenesis of metabolic dysfunction-associated steatotic liver disease (MASLD) remains incompletely understood. However, recent studies highlight the interactions between muscle, liver, and adipose tissue. This study aimed to explore the relationships between clinical indicators of MASLD and sarcopenia, cardiorespiratory fitness, fatigue, and mood. Materials and Methods: The study involved 60 participants, including 28 healthy controls and 32 with MASLD, categorized into two disease subgroups: 15 with MASL and 17 with metabolic dysfunction-associated steatohepatitis (MASH). Participants completed an incremental speed shuttle walk test to evaluate cardiorespiratory fitness, a hand-held dynamometer assessment for appendicular muscle strength, and the timed up and go test for physical performance. Physical activity level, fatigue, quality of life, and emotional state were assessed using questionnaires. The test results were compared between groups and with disease characteristics. Results: MASL and MASH groups showed reduced cardiorespiratory fitness (p < 0.001). The knee extensors were significantly weaker in both MASL and MASH groups (p < 0.001 and p = 0.001, respectively). The MASH group reported higher levels of depression and negative health perception (p = 0.006 and p = 0.03, respectively). Muscle strength in patients with MASLD showed a significant negative association with depression (OR = -0.384, 95% CI: -3.10 to -0.74, p = 0.003), intrahepatic triglyceride content (OR = -0.287, 95% CI: -1.31 to -0.11, p = 0.023), and LDL (OR = -0.286, 95% CI: -0.02 to -0.33, p = 0.03). In contrast, a positive association was observed between VO2 and muscle strength (OR = 0.531, 95% CI 1.27 to 3.47, p < 0.001). Conclusions: This study suggests that muscle strength is linked to key metabolic parameters, such as hepatic fat, LDL levels, and aerobic capacity, that may contribute to the development and progression of MASLD. Interventions aimed at preserving or enhancing muscle strength in MASLD patients may be essential for preventing liver damage and improving metabolic health.

Diagnosis and management of metabolic dysfunction- associated steatotic liver disease in South Asians- A clinical review

Background

Metabolic dysfunction-associated steatotic liver disease (MASLD), previously termed as nonalcoholic fatty liver disease (NAFLD) is a hepatic manifestation of obesity and metabolic syndrome. It is mainly caused by insulin resistance. With the increased risk of visceral obesity in South Asians, the prevalence of MASLD is on the rise. The morbidity associated with MASLD and its complications, including hepatocellular carcinoma is projected to increase in this South Asian population.

Methods

In this narrative review we explore the diagnosis and management of MASLD in the South Asian population. We summarize the findings from the recent literature on the diagnostic methods and management options for MASLD in this population.

Results

Through our search we found no specific guidelines for the diagnosis and management of MASLD in the South Asian population. The existing general guidelines may not be applied to South Asian populations due to the differences in phenotype, genotype, social and cultural aspects. South Asian countries also have limited resources with the non-availability of newer pharmacotherapeutic agents.

Conclusion

The goal of this review is to guide obesity physicians and primary care providers to have a stepwise approach to treat patients at risk for MASLD with a main focus on interdisciplinary management most applicable to South Asian patients. More research is needed to formulate guidelines and algorithm that are specific for the South Asian population.

Clinical Impact of Sarcopenia Screening on Long-Term Mortality in Patients Undergoing Coronary Bypass Grafting

BACKGROUND

Sarcopenia is an aging-related condition characterized by loss of skeletal muscle mass and is an indicator of subclinical atherosclerosis. The relationship between reduced muscle mass and long-term clinical outcomes in patients with advanced coronary artery disease who have undergone coronary artery bypass grafting (CABG) is not fully understood. This study is sought to evaluate the prognostic implications of sarcopenia screening in patients undergoing CABG.

METHODS

A total of 2810 patients who underwent CABG were analysed and classified according to presence of reduced muscle mass. The skeletal muscle index (SMI) was calculated as L3 muscle area (cm2)/height (m)2 on computed tomography. Reduced SMI was defined as SMI ≤ 45 cm2/m2 in male and ≤ 38 cm2/m2 in female. The primary outcome was all-cause mortality, and survival analysis was performed using the Kaplan-Meier method and compared with the log-rank test.

RESULTS

The median follow-up was 8.7 years, and 924 patients (32.9%) had reduced SMI. Patients with reduced SMI were older (67.7 ± 8.8 vs. 62.2 ± 9.8 years; p < 0.001) and less frequently male (69.8% vs. 81.1%; p < 0.001). SMI was significantly associated with risk of death on a restricted cubic spline curve (HR = 1.04 per-1 decrease; 95% CI 1.03-1.05; p < 0.001). Patients with reduced SMI had a higher incidence of long-term mortality than those with preserved SMI (survival rate 41.4% vs. 62.8%; HRadj = 1.18, 95% CI 1.03-1.36, p = 0.020). Subgroup analysis showed that the prognostic implication of reduced SMI on long-term survival was more evident in male (HRadj = 2.01, 95% CI 1.72-2.35) than female (HRadj = 1.28, 95% CI 0.98-1.68) (interaction p = 0.006).

CONCLUSIONS

Reduced muscle mass, defined by SMI on computed tomography, was associated with long-term mortality after CABG. These results provide contemporary data to allow the evaluation of physical frailty in patients with advanced coronary artery disease before surgery.

TRIAL REGISTRATION

Long-Term Outcomes and Prognostic Factors in Patients Undergoing CABG or PCI: NCT03870815.

Development and external validation of a machine-learning based model to predict pre-sarcopenia in MASLD population: Results from NHANES 2017-2018

INTRODUCTION AND OBJECTIVES

With rising prevalence of pre-sarcopenia in metabolic dysfunction-associated steatotic liver disease (MASLD), this study aimed to develop and validate machine learning-based model to identify pre-sarcopenia in MASLD population.

MATERIALS AND METHODS

A total of 571 MASLD subjects were screened from the National Health and Nutrition Examination Survey 2017-2018. This cohort was randomly divided into training set and internal testing set with a ratio of 7:3. Sixty-six MASLD subjects were collected from our institution as external validation set. Four binary classifiers, including Random Forest (RF), support vector machine, and extreme gradient boosting and logistic regression, were fitted to identify pre-sarcopenia. The best-performing model was further validated in external validation set. Model performance was assessed in terms of discrimination and calibration. Shapley Additive explanations were used for model interpretability.

RESULTS

The pre-sarcopenia rate was 17.51 % and 15.16 % in NHANES cohort and external validation set, respectively. RF outperformed other models with area under receiver operating characteristic curve (AUROC) of 0.819 (95 %CI: 0.749, 0.889). When six top-ranking features were retained as per variable importance, including weight-adjusted waist, sex, race, creatinine, education and alkaline phosphatase, a final RF model reached an AUROC being 0.824 (0.737, 0.910) and 0.732 (95 %CI: 0.529, 0.936) in internal and external validation sets, respectively. The model robustness was proved in sensitivity analysis. The calibration curve and decision curve analysis confirmed a good calibration capacity and good clinical usage.

CONCLUSIONS

This study proposed a user-friendly model using explainable machine learning algorithm to predict pre-sarcopenia in MASLD population. A web-based tool was provided to screening pre-sarcopenia in community and hospitalization settings.

MAFLD in adults: non-invasive tests for diagnosis and monitoring of MAFLD

Metabolic dysfunction-associated fatty liver disease (MAFLD) is the liver manifestation of a metabolic syndrome and is highly prevalent in the general population. There has been significant progress in non-invasive tests for MAFLD, from the diagnosis of fatty liver and monitoring of liver fat content in response to intervention, to evaluation of liver fibrosis and its change over time, and from risk stratification of patients within the context of clinical care pathways, to prognostication. Various non-invasive tests have also been developed to assess for fibrotic metabolic dysfunction-associated steatohepatitis, which has emerged as an important diagnostic goal, particularly in the context of clinical trials. Non-invasive tests can be used to diagnose clinically significant portal hypertension so that intervention can be administered to reduce the risk of decompensation. Furthermore, the use of risk stratification algorithms can identify at-risk patients for hepatocellular carcinoma surveillance. Beyond the liver, various tests that evaluate cardiovascular disease risk, assess sarcopenia and measure patient reported outcomes, can be utilized to improve the care of patients with MAFLD. This review provides an up-to-date overview of these non-invasive tests and the limitations of liver biopsy in the management of patients with MAFLD.

Exploring the impact of protein intake on the association between oxidative balance score and lean mass in adults aged 20-59: NHANES 2011-2018

BACKGROUND

Previous studies have established a correlation between the pathogenesis of oxidative stress and sarcopenia. The Oxidative Balance Score (OBS) is an integrated measure that reflects the overall balance of antioxidants and pro-oxidants in dietary components and lifestyle. However, there are limited reports on the association between OBS and lean mass and the impact of protein intake on the association between OBS and lean mass.

METHODS

Using data from the National Health and Nutrition Examination Survey from 2011 to 2018, multivariate linear and logistic regression analyses were conducted to explore the associations between OBS and outcomes. The findings were then illustrated through fitted smoothing curves and threshold effect analyses.

RESULTS

This study included 2,441 participants, demonstrating that higher OBS is significantly associated with an increased ratio of appendicular lean mass to body mass index. Key inflection points at OBS 31 mark pronounced changes in these associations, with age and protein intake notably affecting the association. The effect of OBS on lean mass varies among populations with high and low protein intake.

CONCLUSIONS

Our findings suggest that OBS is significantly and positively associated with lean mass. A high protein intake of more than 84.5 g/day may enhance the role of OBS in influencing muscle health to improve muscle outcomes.

The prevalence and effects of sarcopenia in patients with metabolic dysfunction-associated steatotic liver disease (MASLD): A systematic review and meta-analysis

BACKGROUND AND AIMS

Sarcopenia is a common complication in patients with metabolic dysfunction-associated steatotic liver disease (MASLD). However, the prevalence and its impact on the survival of sarcopenia in patients with MASLD is unknown. In this study, we aimed to assess the prevalence and effects of sarcopenia in patients with MASLD.

METHODS

Systematic review and meta-analysis of full texts of relevant studies were searched from inception until June 12, 2024 in five databases (PubMed, Cochrane Library, Embase, Web of Science, and the China National Knowledge Infrastructure). Next, we assessed the prevalence of sarcopenia in MASLD, and calculated the ORs and HRs between sarcopenia and MASLD based on the adjusted data from individual studies. Statistical analyses were performed using Stata 11.0.

RESULTS

Of the 2984 records considered, 29 studies recruiting 63,330 patients were included. The pooled prevalence of sarcopenia in patients with MASLD was 23.5% overall (95% CI; 19.1%-27.9%, I2 = 99.6%), and was higher in Asian patients, male, cross-sectional studies, when BIA were employed to measure muscle mass, one criterion of diagnosis sarcopenia, MASLD was diagnosed employing MRI, and moderate-quality studies. Sarcopenia was associated with MASLD patients (adjusted odds ratio [aOR] 2.08, 95% CI 1.58-2.74, I2 = 93.6%) with similar findings in subgroups stratified by age, study design, methods for measuring muscle mass, assessment method to detect sarcopenia, and study quality. The association between all-cause mortality further supports the association between sarcopenia and poor prognosis with MASLD (aHR 1.59, 95% CI 1.33-1.91, I2 = 0%).

CONCLUSIONS

Sarcopenia was strongly associated with MASLD progression and was a risk factor not only for MASLD pathogenesis but was also markedly correlated with MASLD-associated mortality.

The association between non‑high‑density lipoprotein cholesterol to high‑density 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.

Sarcopenia and metabolic dysfunction associated steatotic liver disease: Time to address both

Sarcopenia and metabolic dysfunction associated steatotic liver disease (MASLD) are closely intertwined. Sarcopenia, traditionally a disease of the older adult and chronic disease population, has been closely studied as one of the pathophysiologic conditions at play in the development of MASLD. They share similar risk factors of insulin resistance and physical inactivity. Given similar pathophysiology along the liver-muscle axis, sarcopenia has been studied as a risk factor for MASLD, and vice versa. Current research suggests a bidirectional relationship. Given the chronicity of MASLD as a chronic inflammatory liver disease, it can break down muscle mass and lead to sarcopenia, while sarcopenia promotes intramuscular lipid accumulation that releases cytokines that can aggravate inflammation in the liver. However, for the longest time, a lack of consensus definition for MASLD and sarcopenia made it difficult to study their relationship and outcomes. A recent nomenclature update to diagnosing MASLD has made it easier for researchers to identify cohorts for study. However, no gold standard technique to measure muscle mass or consensus sarcopenia definition has been identified yet. Future studies are needed to reach a consensus and reduce diagnostic variation. With similar pathophysiology and shared risk factors between the two diseases, future research may also identify potential therapeutic targets along the liver-muscle axis that would benefit both sarcopenia and MASLD in order to maximize their outcomes.

Natural history of lean and non-lean metabolic dysfunction-associated steatotic liver disease

BACKGROUND

Conflicting evidence regarding the prognosis of lean metabolic dysfunction-associated steatotic liver disease (MASLD) has raised substantial questions.

AIM

This study aimed to elucidate the prognosis of lean MASLD by conducting a comprehensive analysis of a vast Asian cohort.

METHODS

This study used a nationwide, population-based database and analyzed 2.9 million patients. The primary endpoints were liver-related events (LREs) and cardiovascular events (CVEs) in patients with lean MASLD, non-lean MASLD, and normal liver control groups.

RESULTS

The median observation period was 4.2 years. The 5-year incidence values of LREs in the lean MASLD, non-lean MASLD, and normal liver control groups were 0.065%, 0.039%, and 0.006%, respectively. The LRE risk of lean MASLD was significantly higher than that of normal liver control (adjusted hazard ratio [aHR]: 5.94, 95% confidence interval [CI]: 3.95-8.92) but comparable to that of non-lean MASLD (aHR: 1.35, 95% CI: 0.87-2.08). By contrast, for CVEs, the non-lean MASLD group exhibited a higher 5-year cumulative incidence rate (0.779%) than the lean MASLD (0.600%) and normal liver control (0.254%) groups. The lean MASLD group had a reduced risk of CVEs compared with the non-lean MASLD group (aHR, 0.73; 95% CI: 0.64-0.84), and comparable risk of CVEs to the normal liver control group (aHR, 0.99; 95% CI: 0.88-1.12).

CONCLUSION

Lean MASLD exhibits a similar LRE risk and a lower CVE risk to non-lean MASLD. Therefore, follow-up and treatment strategies should be tailored to the specific MASLD condition.

Prevalence and outcome of sarcopenia in non-alcoholic fatty liver disease

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) includes a spectrum of conditions, progressing from mild steatosis to advanced fibrosis. Sarcopenia, characterized by decreased muscle strength and mass, shares common pathophysiological traits with NAFLD. An association exists between sarcopenia and increased NAFLD prevalence. However, data on the prevalence of sarcopenia in NAFLD and its impact on the outcomes of NAFLD remain inconsistent.

AIM

To analyze the prevalence and outcomes of sarcopenia in patients with NAFLD.

METHODS

We conducted a comprehensive search for relevant studies in MEDLINE, Embase, and Scopus from their inception to June 2023. We included studies that focused on patients with NAFLD, reported the prevalence of sarcopenia as the primary outcome, and examined secondary outcomes, such as liver fibrosis and other adverse events. We also used the Newcastle-Ottawa scale for quality assessment.

RESULTS

Of the 29 studies included, the prevalence of sarcopenia in NAFLD varied widely (1.6% to 63.0%), with 20 studies reporting a prevalence of more than 10.0%. Substantial heterogeneity was noted in the measurement modalities for sarcopenia. Sarcopenia was associated with a higher risk of advanced fibrosis (odd ratio: 1.97, 95% confidence interval: 1.44-2.70). Increased odds were consistently observed in fibrosis assessment through biopsy, NAFLD fibrosis score/body mass index, aspartate aminotransferase to alanine aminotransferase ratio, diabetes (BARD) score, and transient elastography, whereas the fibrosis-4 score showed no such association. Sarcopenia in NAFLD was associated with a higher risk of steatohepatitis, insulin resistance, cardiovascular risks, and mortality.

CONCLUSION

This systematic review highlights the critical need for standardized diagnostic criteria and measurement methods for sarcopenia in NAFLD patients. The variability in study designs and assessment methods for sarcopenia and liver fibrosis may account for the inconsistent findings. This review demonstrates the multidimensional impact of sarcopenia on NAFLD, indicating its importance beyond liver-related events to include cardiovascular risks, mortality, and metabolic complications.

Approaching the Sarcopenic Patient with Nonalcoholic Steatohepatitis-related Cirrhosis

Sarcopenia is a well-known complication of chronic liver disease (CLD), and it is almost always observed in patients with cirrhosis, at least in those with decompensated disease. Since nonalcoholic fatty liver disease (NAFLD), recently renamed metabolic dysfunction-associated steatotic liver disease (MASLD), is becoming the leading cause of end-stage liver disease, a new scenario characterized by the frequent coexistence of NAFLD, obesity, and sarcopenia is emerging. Although it is not yet resolved whether the bidirectional relationship between sarcopenia and NAFLD subtends causal determinants, it is clear that the interaction of these two conditions is associated with an increased risk of poor outcomes. Notably, during the course of CLD, deregulation of the liver-muscle-adipose tissue axis has been described. Unfortunately, owing to the lack of properly designed studies, specific therapeutic guidelines for patients with sarcopenia in the context of NAFLD-related CLD have not yet been defined. Strategies aimed to induce the loss of fat mass together with the maintenance of lean body mass seem most appropriate. This can be achieved by properly designed diets integrated with specific nutritional supplementations and accompanied by adequate physical exercise. Future studies aiming to add to the knowledge of the correct assessment and approach to sarcopenia in the context of NAFLD-related CLD are eagerly awaited.

Metabolic-associated fatty liver disease and sarcopenia: A double whammy

The prevalence of metabolic-associated fatty liver disease (MAFLD) has increased substantially in recent years because of the global obesity pandemic. MAFLD, now recognized as the number one cause of chronic liver disease in the world, not only increases liver-related morbidity and mortality among sufferers but also worsens the complications associated with other comorbid conditions such as cardiovascular disease, type 2 diabetes mellitus, obstructive sleep apnoea, lipid disorders and sarcopenia. Understanding the interplay between MAFLD and these comorbidities is important to design optimal therapeutic strategies. Sarcopenia can be either part of the disease process that results in MAFLD (e.g., obesity or adiposity) or a consequence of MAFLD, especially in the advanced stages such as fibrosis and cirrhosis. Sarcopenia can also worsen MAFLD by reducing exercise capacity and by the production of various muscle-related chemical factors. Therefore, it is crucial to thoroughly understand how we deal with these diseases, especially when they coexist. We explore the pathobiological interlinks between MAFLD and sarcopenia in this comprehensive clinical update review article and propose evidence-based therapeutic strategies to enhance patient care.

Association between manganese exposure in heavy metals mixtures and the prevalence of sarcopenia in US adults from NHANES 2011-2018

Environmental pollution is identified as an essential risk factor for sarcopenia. However, the effect of manganese (Mn) exposure on the prevalence of sarcopenia is not assessed. Our study investigated the correlation between blood Mn concentration and sarcopenia risk in the National Health and Nutrition Examination Survey (NHANES) from 2011 to 2018. Three statistical methods were used to assess these correlations. Mediation analysis was performed to explore the role of inflammation in Mn exposure-induced sarcopenia. Of the 4957 individuals enrolled in this study, 398 (8 %) were diagnosed with sarcopenia. We found a positive association between the log10 Mn concentration and the prevalence of sarcopenia in the logistic regression model. Moreover, heavy metals mixtures were positively correlated with the prevalence of sarcopenia, with Mn identified as the main contributor to this association in the weighted quantile sum (WQS) and Bayesian kernel machine regression (BKMR) models. Furthermore, inflammation mediated the relationship between Mn exposure and the prevalence of sarcopenia, explaining 7.29 % of the effect (odds ratio: 0.03, 0.19, P = 0.002). Thus, our study results revealed that excessive Mn exposure is a contributing factor for sarcopenia. More prospective studies are required to examine the association between Mn exposure and the prevalence of sarcopenia.

The association of testosterone with sarcopenia and frailty in chronic liver disease

BACKGROUND

Testosterone is an important anabolic hormone responsible for maintaining body composition and muscle mass and circulates mostly albumin-bound, or sex hormone binding globulin (SHBG)-bound or free in the plasma. Of these fractions, the latter is bioactive and exerts the androgenic effects on male population. Liver cirrhosis, the advanced stage of any chronic liver disease characterized by permanent distortions to the hepatic architecture, disrupts the hypothalamic-pituitary-gonadal axis, leading to diminished levels of free testosterone and hypogonadism.

METHODS

We retrieved the PubMed database to provide a synopsis of testosterone's physiology and action and summarize the effect of sarcopenia in pre-cirrhotic and cirrhotic patients. Moreover, we scoped to provide insight into the relationship of testosterone levels with sarcopenia, frailty and survival in cirrhotic and non-cirrhotic population as well as to discuss the efficacy of exogenous testosterone supplementation on the anthropometric parameters and survival of those patients.

RESULTS

Low testosterone levels have been associated with sarcopenia, reduced body lean mass, decreased bone mineral density and frailty, thus leading to increased morbidity and mortality especially among cirrhotic patients. Furthermore, exogenous testosterone administration significantly ameliorated body composition on patients with chronic hepatic disease, without significant adverse effects. However, the current literature does not suggest any significant effect on survival of those patients. Moreover, the long-term safety of testosterone use remains an open question.

CONCLUSION

Low serum testosterone is strongly correlated with sarcopenia, frailty, higher rate of hepatic decompensation and mortality. Nonetheless, exogenous supplementation of testosterone did not ameliorate the liver-related outcomes and complications.

NAFLD Associates with Sarcopenia Defined by Muscle Mass and Slow Walking Speed: A Cross-Sectional Analysis from the Framingham Heart Study

Sarcopenia is associated with NAFLD. It is unknown if the association is explained by shared risk factors. Our study sought to investigate the association between liver fat and sarcopenia in our cohort. Liver fat was measured on CT between 2008 and 2011. We excluded heavy alcohol use and missing covariates. Muscle mass in a subset (n = 485) was measured by 24 h urinary creatinine. Physical function was defined by h strength and walking speed. Sarcopenia was defined as low muscle mass and/or low physical function. We created multivariable-adjusted regression models to evaluate cross-sectional associations between liver fat and low muscle mass, grip strength, and walking speed. The prevalence of hepatic steatosis was 30% (n = 1073; 58.1% women; mean age 65.8 ± 8.6 years). There was a significant positive association between liver fat and muscle mass in linear regression models. The association was not significant after adjusting for BMI. The odds of sarcopenia increased by 28% for each SD in liver fat (OR 1.28; 95% CI 1.02, 1.60) and persisted after accounting for confounders in multivariable-adjusted models (OR 1.30, 95% CI 1.02, 1.67). Further studies are needed to determine if there is a causal relationship between liver fat and sarcopenia and whether treatment of sarcopenia improves liver fat.

Metabolic associated fatty liver disease and sarcopenia additively increase mortality: a real-world study

BACKGROUND AND AIMS

Sarcopenia is associated with worse prognosis for non-alcoholic fatty liver disease (NAFLD). However, disease progression in the MAFLD-related sarcopenia is largely unknown. We aimed to clarify the relationship between MAFLD and/or sarcopenia with mortality and liver fibrosis in the real world.

METHODS

A total of 13,692 individuals were selected from the third National Health and Nutrition Examination Surveys and linked mortality until December 2019. MAFLD is diagnosed based on a radiologically diagnosed hepatic steatosis and the presence of any one of the following three conditions: overweight/obesity, diabetes mellitus (DM), or metabolic dysregulation. Sarcopenia is defined by weight-adjusted skeletal muscle mass.

RESULTS

The mean age was 43.7 ± 15.97 years, and 47.3% of the individuals were male. MAFLD was diagnosed in 4207/13,692 (30.73%) participants, and the proportion of sarcopenic was 19.42% amongst subjects with MAFLD. The mean follow-up duration was of 23.7 ± 7.62 years. MAFLD (aHR 1.152, 95% CI 1.070-1.241) and sarcopenia (aHR 1.123, 95% CI 1.042-1.210) were related to increased all-cause mortality in MAFLD after adjustment for age, sex, race, marital status, education, and smoking. Stratified analysis revealed that MAFLD and sarcopenia additively increased the risk of mortality (aHR 1.247, 95% CI 1.132-1.373) and liver fibrosis (aOR 2.296, 95% CI 1.718-3.069 assessed by NFS score >0.676; aOR 2.218, 95% CI 1.788-2.752 assessed by FIB-4 score >1.3) in fully adjusted models (P < 0.001 for all).

CONCLUSION

Sarcopenia in individuals with MAFLD portends increased mortality and significant liver fibrosis. Novel therapeutic strategies targeting at increasing skeletal muscle mass should be explored for patients with MAFLD.

Impact of skeletal muscle mass evaluating methods on severity of metabolic associated fatty liver disease in non-elderly adults

The study aimed to explore the relationships of skeletal muscle mass with disease severity in metabolic-associated fatty liver disease (MAFLD) patients with different methods. Consecutive subjects undergoing bioelectrical impedance analysis were included. The steatosis grade and liver fibrosis were evaluated by MRI-derived proton density fat fraction and two-dimensional shear wave elastography. The appendicular skeletal muscle mass (ASM) was adjusted by height2 (ASM/H2), weight (ASM/W) and BMI (ASM/BMI). Overall, 2223 subjects (50·5 %, MAFLD; 46·9 %, male) were included, with the mean age 37·4 ± 10·6 years. In multivariate logistic regression analysis, the subjects with the lowest quartile (Q1) of ASM/W or ASM/BMI had higher risk ratios for MAFLD (OR (95 % CI) in male: 2·57 (1·35, 4·89), 2·11(1·22, 3·64); in female: 4·85 (2·33, 10·01), 4·81 (2·52, 9·16), all P < 0·05, all for Q1 v. Q4). The MAFLD patients with lower quartiles of ASM/W had the higher risk OR for insulin resistance (IR), both in male and female (2·14 (1·16, 3·97), 4·26 (1·29, 14·02) for Q4 v. Q1, both P < 0·05). While the significant OR were not observed when ASM/H2 and ASM/BMI were used. There were significant dose-dependent associations between decreased ASM/W as well as ASM/BMI and moderate-severe steatosis (2·85(1·54, 5·29), 1·90(1·09, 3·31), both P < 0·05) in male MAFLD patients. In conclusion, ASM/W is superior to ASM/H2 and ASM/BMI in predicting the degree of MAFLD. A lower ASM/W is associated with IR and moderate-severe steatosis in non-elderly male MAFLD.

Sarcopenia, sarcopenic obesity and nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD), sarcopenia and sarcopenic obesity (SO) are highly prevalent conditions that may coexist, especially in the aging population, without any approved pharmacologic treatment for all of them. There are multiple pathophysiologic mechanisms suggested to explain an association between NAFLD and sarcopenia or SO, including alterations in the adipokines, cytokines, hepatokines and myokines, which may interplay with other factors, such as aging, diet and physical inactivity. In clinical terms, most observational studies support an association between NAFLD and sarcopenia or SO; importantly, there are few cohort studies indicating higher mortality in patients with NAFLD and sarcopenia. Their association also bears some treatment considerations: for example, pioglitazone or vitamin E, suggested as off label treatment for selected patients with nonalcoholic steatohepatitis, may be recommended in the coexistence of sarcopenia or SO, since limited evidence did not show adverse effects of them on sarcopenia and abdominal obesity. In this review, evidence linking sarcopenia and SO with NAFLD is summarized, with a special focus on clinical data. A synopsis of the major pathophysiological links between NAFLD and sarcopenia/SO is initially presented, followed by selected clinical studies and, finally, treatment considerations in patients with NAFLD and sarcopenia or SO are discussed.

Metabolic Dysfunction-Associated Steatotic Liver Disease (MASLD): A State-of-the-Art Review

Metabolic dysfunction-associated steatotic liver disease (MASLD) is the latest term for steatotic liver disease associated with metabolic syndrome. MASLD is the most common cause of chronic liver disease and is the leading cause of liver-related morbidity and mortality. It is important that all stakeholders be involved in tackling the public health threat of obesity and obesity-related diseases, including MASLD. A simple and clear assessment and referral pathway using non-invasive tests is essential to ensure that patients with severe MASLD are identified and referred to specialist care, while patients with less severe disease remain in primary care, where they are best managed. While lifestyle intervention is the cornerstone of the management of patients with MASLD, cardiovascular disease risk must be properly assessed and managed because cardiovascular disease is the leading cause of mortality. No pharmacological agent has been approved for the treatment of MASLD, but novel anti-hyperglycemic drugs appear to have benefit. Medications used for the treatment of diabetes and other metabolic conditions may need to be adjusted as liver disease progresses to cirrhosis, especially decompensated cirrhosis. Based on non-invasive tests, the concepts of compensated advanced chronic liver disease and clinically significant portal hypertension provide a practical approach to stratifying patients according to the risk of liver-related complications and can help manage such patients. Finally, prevention and management of sarcopenia should be considered in the management of patients with MASLD.

Mortality and Liver-Related Events in Lean Versus Non-Lean Nonalcoholic Fatty Liver Disease: A Systematic Review and Meta-analysis

BACKGROUND & AIMS

Although approximately 40% of patients with nonalcoholic fatty liver disease (NAFLD) are nonobese or lean, little is known about the long-term clinical outcomes of lean NAFLD. We aimed to estimate the risk of mortality and adverse liver-related events in patients with lean NAFLD compared with those with non-lean NAFLD.

METHODS

We searched the PubMed, Embase, and Cochrane Library databases through May 2022 for articles reporting mortality and/or development of cirrhosis among lean and non-lean NAFLD patients. The relative risks (RRs) of all-cause mortality, cardiovascular mortality, liver-related mortality, and occurrence of decompensated cirrhosis or hepatocellular carcinoma were pooled using the random-effects model. We also performed subgroup analysis according to characteristics of the study population, methods of NAFLD diagnosis, study design, study region, and length of follow-up.

RESULTS

We analyzed 10 cohort studies involving 109,151 NAFLD patients. Patients with lean NAFLD had comparable risks for all-cause mortality (RR, 1.09; 95% confidence interval [CI], 0.66-1.90), cardiovascular mortality (RR, 1.12; 95% CI, 0.66-1.90), and adverse liver events including decompensated cirrhosis and hepatocellular carcinoma (RR, 0.81; 95% CI, 0.50-1.30). However, the risk of liver-related mortality was higher in patients with lean than non-lean NAFLD (RR, 1.88; 95% CI, 1.02-3.45).

CONCLUSIONS

This study highlights a higher risk of liver-related mortality in patients with lean NAFLD than those with non-lean NAFLD. This finding indicates that further understanding of the pathophysiology, risk factors of adverse outcomes, and genetic and ethnic variabilities of lean NAFLD phenotype is warranted for individualized treatment strategies in lean NAFLD patients.

Lean nonalcoholic fatty liver disease and sarcopenia

Nonalcoholic fatty liver disease (NAFLD) has become one of the most common chronic liver diseases in the world. The risk factor for NAFLD is often considered to be obesity, but it can also occur in people with lean type, which is defined as lean NAFLD. Lean NAFLD is commonly associated with sarcopenia, a progressive loss of muscle quantity and quality. The pathological features of lean NAFLD such as visceral obesity, insulin resistance, and metabolic inflammation are inducers of sarcopenia, whereas loss of muscle mass and function further exacerbates ectopic fat accumulation and lean NAFLD. Therefore, we discussed the association of sarcopenia and lean NAFLD, summarized the underlying pathological mechanisms, and proposed potential strategies to reduce the risks of lean NAFLD and sarcopenia in this review.

Clinics in Liver Disease: Update on Nonalcoholic Steatohepatitis: Sarcopenia and Nonalcoholic Fatty Liver Disease

Dual diagnoses of sarcopenia and nonalcoholic fatty liver disease (NAFLD) increase the risk of all cause mortality and severe liver disease, regardless of nationality. General agreement about diagnostic criteria for sarcopenia includes loss of skeletal muscle mass, weakness, and reduced physical performance. Histopathology demonstrates loss of type 2 muscle fibers, more than type 1 fibers and myosteatosis, a risk factor for severe liver disease. Low skeletal mass and NAFLD are inversely related; the mechanism is through decreased insulin signaling and insulin resistance, critical for metabolic homeostasis. Weight loss, exercise, and increased protein intake have been effective in reducing NAFLD and sarcopenia.

Vigorous physical activity provides protection against all-cause deaths among adults patients with nonalcoholic fatty liver disease (NAFLD)

BACKGROUND

Mortality benefits of vigorous leisure time physical activity (LTPA) among adults with NAFLD is not known.

AIM

To investigate association between LTPA and reduction in all-cause mortality among adults with NAFLD.

METHODS

We used NHANES (1999-2006) self-reported PA data for adults (≥40 years) with mortality follow-up through December 31, 2015. US-Fatty Liver Index in absence of secondary causes identified NAFLD. Moderate and vigorous LTPA were calculated by the 2018 PA Guidelines for Americans.

RESULTS

NAFLD prevalence among 5211 adults (46.2% male; 75.8% white; mean age 53.2 years) was 32.7%. Adults with NAFLD were less likely to report the recommended minimal PA (≥ 150 min/week, 55.5% vs 64.8%) or highly active PA (≥300 min/week, 39.2% vs 48.5%) compared to adults without NAFLD. Over a median follow-up of 12.3 years, 355 deaths among adults with NAFLD and 510 deaths among adults without NAFLD were registered. In the metabolic comorbidities-adjusted model, adults with NAFLD who reported ≥50% of their total PA as vigorous activity had a 56% reduction in all-cause mortality risk (HR:0.44, 95%CI: 0.25-0.76) and cancer-specific mortality risk (HR: 0.21, 0.06-0.66) but not cardiac-specific mortality (p > 0.05) compared to adults with NAFLD who did not report any LTPA. This association remained significant even among adults with NAFLD who met the recommended minimal PA, among adults with NAFLD who reported any LTPA, and among adults with NAFLD who had metabolic abnormalities and in sensitivity analysis.

CONCLUSIONS

Engaging in vigorous activity is beneficial for adults with NAFLD - especially those with metabolic abnormalities.

Grip Strength and Sarcopenia Predict 2-Year Cognitive Impairment in Community-Dwelling Older Adults

OBJECTIVES

Using the Asian Working Group for Sarcopenia (AWGS2019) and the European Working Group on Sarcopenia in Older People (EWGSOP2) criteria, this study examined associations of sarcopenia and its components with specific domains of cognitive impairment over time.

DESIGN

A prospective cohort study with a 2-year follow-up.

SETTING AND PARTICIPANTS

This study is part of the Taiwan Initiatives for Geriatric Epidemiological Research (TIGER), which recruited participants aged 65 years old who attended the senior health checkup program at National Taiwan University Hospital (NTUH).

METHODS

Grip strength was measured using a handgrip dynamometer. Walking speed (m/s) was measured as the time required to walk 8 feet. Muscle mass was measured by performing a bioelectrical impedance analysis. Global cognition (assessed using the Taiwanese version of the Montreal Cognitive Assessment) and 4 cognitive domains (memory, executive function, verbal fluency, and attention) were assessed over time. Associations of sarcopenia and its components with cognitive impairment were evaluated after stratification by sex using generalized linear mixed models adjusted for essential covariates for cognitive impairment.

RESULTS

Compared with robust women, those with severe sarcopenia were more likely to have a global cognitive impairment over time (β = -0.87, P = .03 based on AWGS2019 criteria and β = -1.07, P = .02 based on the EWGSOP2 criteria). Among men, low grip strength was associated with poor scores on measures of global cognition (β = -0.80, P = .03), executive function (β = -0.35, P = .001), verbal fluency (β = -0.31, P = .02), and attention (β = -0.34, P = .008) over time.

CONCLUSIONS AND IMPLICATIONS

Severe sarcopenia predicted global and specific domains of cognitive impairment in older adults. Poor grip strength predicted cognitive impairment in men but not in women. A screen for sarcopenia severity and low muscle strength may be used to identify the risk of cognitive impairment.

Metabolic-Associated Fatty Liver Disease and Sarcopenia

The current evidence indicates a strong association between sarcopenia, the loss of muscle mass and strength, and metabolic-associated fatty liver disease (MAFLD). The two entities share many common pathophysiologic mechanisms, and their coexistence may result in higher rates of morbidity and mortality. Therefore, given their increasing incidence in the modern world, there is a need for a better understanding of the liver-muscle axis for early identification of sarcopenia in patients with MAFLD and vice versa. This review aims at presenting current data regarding the correlation between sarcopenia and MAFLD, the associated comorbidities, and the need for effective therapies.

Impact of Sarcopenia on Non-Alcoholic Fatty Liver Disease

With the increasing incidence of non-alcoholic fatty liver disease (NAFLD) and the aging of the population, sarcopenia is attracting attention as one of the pathological conditions involved in the development and progression of NAFLD. In NAFLD, sarcopenia is closely associated with insulin resistance and results from the atrophy of skeletal muscle, an insulin target organ. In addition, inflammatory cytokines that promote skeletal muscle protein breakdown, low adiponectin levels leading to decreased insulin sensitivity, and hyperleptinemia are also involved in NAFLD pathogenesis. The presence of sarcopenia is a prognostic factor and increases the risk of mortality in patients with cirrhosis and post-treatment liver cancer. Sarcopenia, the presence of which mainly occurs due to decreased muscle mass, combined with increased visceral fat, can lead to sarcopenia-associated obesity, which increases the risk of NASH, liver fibrosis, and cardiovascular disease. In order to treat sarcopenia, it is necessary to properly evaluate sarcopenia status. Patients with high BMI, as in sarcopenic obesity, may improve with caloric restriction. However, inadequate oral intake may lead to further loss of muscle mass. Aerobic and resistance exercise should also be used appropriately.

Causes and risk profiles of mortality among individuals with nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver disease in the United States and worldwide. Though nonalcoholic fatty liver per se may not be independently associated with an increased risk for all-cause mortality, it is associated with a number of harmful metabolic risk factors, such as type 2 diabetes mellitus, hyperlipidemia, obesity, a sedentary lifestyle, and an unhealthy diet. The fibrosis stage is a predictor of all-cause mortality in NAFLD. Mortality in individuals with NAFLD has been steadily increasing, and the most common cause-specific mortality for NAFLD is cardiovascular disease, followed by extra-hepatic cancer, liver-related mortality, and diabetes. High-risk profiles for mortality in NAFLD include PNPLA3 I148M polymorphism, low thyroid function and hypothyroidism, and sarcopenia. Achieving weight loss through adherence to a high-quality diet and sufficient physical activity is the most important predictor of improvement in NAFLD severity and the benefit of survival. Given the increasing health burden of NAFLD, future studies with more long-term mortality data may demonstrate an independent association between NAFLD and mortality.

Assessing causal relationships between sarcopenia and nonalcoholic fatty liver disease: A bidirectional Mendelian randomization study

BACKGROUND AND AIMS

Sarcopenia has been demonstrated to be closely associated with nonalcoholic fatty liver disease (NAFLD). However, whether there are causal relationships between sarcopenia and NAFLD remains undetermined. Here, we aim to address the question using a two-sample bidirectional Mendelian randomization (MR) analysis approach.

METHODS

We performed a two-sample bidirectional MR study using summary-level data from genome-wide association studies (GWAS) of the whole body lean mass (n = 38,292), appendicular (arms and legs) lean mass (n = 28,330), and NAFLD (1,483 biopsy-proven NAFLD cases and 17,781 controls). We first conducted MR analysis with five single nucleotide polymorphisms (SNPs) as genetic instruments for whole body lean mass and three SNPs as instruments for appendicular lean mass to estimate the causal effect of genetically predicted sarcopenia on the risk of NAFLD using the inverse-variance weighted (IVW) method. Then we performed reverse MR analysis with four SNPs as instruments to examine the causality of genetically predicted NAFLD with whole body lean mass and appendicular lean mass. Further sensitivity analysis was conducted to testify the reliability of the MR results.

RESULTS

Genetic predisposition to decreased whole body lean mass was not associated with NAFLD [IVW-random effects, odds ratio (OR) = 1.054, 95%CI: 0.750-1.482, P = 0.761]. Similar results were observed using genetic instruments of appendicular lean mass (IVW-random effects, OR = 0.888, 95%CI: 0.386-2.042, P = 0.780). Reverse MR analysis revealed that genetically predicted NAFLD using four genetic instruments was not associated with whole body lean mass (IVW, β = -0.068, 95%CI: -0.179 to 0.043, P = 0.229) and appendicular lean mass (IVW, β = -0.020, 95%CI: -0.092 to 0.051, P = 0.574). MR analyses using other methods and sensitivity analysis showed consistent results.

CONCLUSION

These results suggested no causal relationships between sarcopenia and NAFLD, indicating that sarcopenia may not be directly involved in the pathogenesis of NAFLD and vice versa.

Liver Fibrosis Marker and Postoperative Mortality in Patients Without Overt Liver Disease

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) can progress to advanced fibrosis, which, in the nonsurgical population, is associated with poor hepatic and extrahepatic outcomes. Despite its high prevalence, NAFLD and related liver fibrosis may be overlooked during the preoperative evaluation, and the role of liver fibrosis as an independent risk factor for surgical-related mortality has yet to be tested. The aim of this study was to assess whether fibrosis-4 (FIB-4), which consists of age, aspartate aminotransferase (AST), alanine aminotransferase (ALT), and platelets, a validated marker of liver fibrosis, is associated with postoperative mortality in the general surgical population.

METHODS

A historical cohort of patients undergoing general anesthesia at an academic medical center between 2014 and 2018 was analyzed. Exclusion criteria included known liver disease, acute liver disease or hepatic failure, and alcohol use disorder. FIB-4 score was categorized into 3 validated predefined categories: FIB-4 ≤1.3, ruling out advanced fibrosis; >1.3 and <2.67, inconclusive; and ≥2.67, suggesting advanced fibrosis. The primary analytic method was propensity score matching (FIB-4 was dichotomized to indicate advanced fibrosis), and a secondary analysis included a multivariable logistic regression.

RESULTS

Of 19,861 included subjects, 1995 (10%) had advanced fibrosis per FIB-4 criteria. Mortality occurred intraoperatively in 15 patients (0.1%), during hospitalization in 272 patients (1.4%), and within 30 days of surgery in 417 patients (2.1%). FIB-4 ≥2.67 was associated with increased intraoperative mortality (odds ratio [OR], 3.63; 95% confidence interval [CI], 1.25-10.58), mortality during hospitalization (OR, 3.14; 95% CI, 2.37-4.16), and within 30 days from surgery (OR, 2.46; 95% CI, 1.95-3.10), after adjusting for other risk factors. FIB-4 was related to increased mortality in a dose-dependent manner for the 3 FIB-4 categories ≤1.3 (reference), >1.3 and <2.67, and ≥2.67, respectively; during hospitalization (OR, 1.89; 95% CI, 1.34-2.65 and OR, 4.70; 95% CI, 3.27-6.76) and within 30 days from surgery (OR, 1.77; 95% CI, 1.36-2.31 and OR, 3.55; 95% CI, 2.65-4.77). In a 1:1 propensity-matched sample (N = 1994 per group), the differences in mortality remained. Comparing the FIB-4 ≥2.67 versus the FIB-4 <2.67 groups, respectively, mortality during hospitalization was 5.1% vs 2.2% (OR, 2.70; 95% CI, 1.81-4.02), and 30-day mortality was 6.6% vs 3.4% (OR, 2.26; 95% CI, 1.62-3.14).

CONCLUSIONS

A simple liver fibrosis marker is strongly associated with perioperative mortality in a population without apparent liver disease, and may aid in future surgical risk stratification and preoperative optimization.

Extrahepatic morbidities and mortality of NAFLD: an umbrella review of meta-analyses

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) has reached pandemic proportions currently and may contribute to multiple extrahepatic outcomes.

AIM

To comprehensively summarise evidence of associations between NAFLD and risk of extrahepatic outcomes.

METHODS

We conducted an umbrella review. We searched PubMed, Web of Science and Cochrane database from inception to 27 November 2021.

RESULTS

We included 22 meta-analyses with 374 original studies in our analysis. Subjects with NAFLD had an increased risk of mortality, multiple cardiovascular complications, extrahepatic cancers, diabetes and chronic kidney disease (CKD) than those without NAFLD. Excess risks of several other extrahepatic outcomes including hypothyroidism, urolithiasis, gastro-oesophageal reflux disease, gallstones, depression and worse maternal and foetal outcomes were also observed in this population. However, associations were not significant for prostate cancer, female organ genital cancer, haematological cancer, diabetic retinopathy or osteoporotic fracture. The risks of CVD, diabetes and CKD were similar in obese and non-obese patients. Most associations were heterogeneous across regions; significantly, Europeans with NAFLD were more prone to all-cause mortality than North Americans. The certainty of evidence was graded from only very low to moderate as all included studies were observational.

CONCLUSIONS

Patients with NAFLD are at heightened risk of extrahepatic outcomes. However, the certainty of evidence is only from very low to moderate. Further studies at low risk of bias are required to support the evidence and elucidate any causal associations.

Muscle strength, but not body mass index, is associated with mortality in patients with non-alcoholic fatty liver disease

BACKGROUND

Whether adiposity and muscle function are associated with mortality risk in patients with non-alcoholic fatty liver disease (NAFLD) remains unknown. We examine the independent and combined associations of body mass index (BMI) and muscle strength with overall mortality in individuals with NAFLD.

METHODS

We analysed data from 7083 participants with NAFLD in the Thai National Health Examination Survey and their linked mortality. NAFLD was defined using a lipid accumulation product in participants without significant alcohol intake. Poor muscle strength was defined by handgrip strength of <28 kg for men and <18 kg for women, according to the Asian Working Group on Sarcopenia. The Cox proportional-hazards model was constructed to estimate the adjusted hazard ratio (aHR) for overall mortality.

RESULTS

The mean age was 49.3 ± 13.2 years, and 69.4% of subjects were women. According to the Asian-specific criteria, 1276 individuals (18.0%) were classified as lean NAFLD (BMI 18.5-22.9 kg/m2 ), 1465 (20.7%) were overweight NAFLD (BMI 23-24.9 kg/m2 ), and 4342 (61.3%) were obese NAFLD (BMI ≥ 25 kg/m2 ). Over 60 432 person-years, 843 participants died. In Cox models adjusted for physiologic, lifestyle, and comorbid factors, individuals with lean NAFLD [aHR 1.18, 95% confidence interval (CI): 0.95-1.48; P = 0.138] and subjects with overweight NAFLD (aHR 1.28, 95% CI: 0.89-1.84; P = 0.158) had mortality risk estimates similar to their obese counterparts, whereas participants with lower handgrip strength had significantly higher mortality risk than those with higher handgrip strength in men and women. Compared with obese individuals with the highest handgrip strength, elevated mortality risk was observed among men (aHR 3.21, 95% CI: 1.35-7.62, P = 0.011) and women (aHR 2.22, 95% CI, 1.25-3.93, P = 0.009) with poor muscle strength. Among men, poor muscle strength was associated with increased risk of mortality with obese NAFLD (aHR 3.94, 95% CI, 1.38-11.3, P = 0.013), overweight NAFLD (aHR 2.93, 95% CI, 1.19-7.19, P = 0.021), and lean NAFLD (aHR 2.78, 95% CI, 0.93-8.32, P = 0.065). Among women, poor muscle strength was associated with increased mortality risk with obese NAFLD (aHR 2.25, 95% CI, 1.06-4.76, P = 0.036), overweight NAFLD (aHR 1.69, 95% CI, 0.81-3.51, P = 0.153), and lean NAFLD (aHR 2.47, 95% CI, 1.06-5.73, P = 0.037).

CONCLUSIONS

In this nationwide cohort of individuals with NAFLD, muscle strength, but not BMI, was independently associated with long-term overall mortality. Measuring handgrip strength can be a simple, non-invasive risk stratification approach for overall mortality in patients with NAFLD.

Comparison of long‐term prognosis between non‐obese and obese patients with non‐alcoholic fatty liver disease

Background and Aim

Non‐alcoholic fatty liver disease (NAFLD) can progress in non‐obese patients as in obese patients. Reports on long‐term prognosis in non‐obese NAFLD patients are controversial. Therefore, we aimed to examine the long‐term prognosis of non‐obese patients with NAFLD.

Methods

This single‐center, retrospective cohort study enrolled biopsy‐proven non‐obese and obese NAFLD patients between January 2002 and December 2011 and followed them up until 31 March 2021, for death and clinical events (cardiovascular and liver‐related events and extrahepatic cancers).

Results

Of the 223 NAFLD patients, 58 (26.0%) were non‐obese. Compared with obese patients, they had a lower fibrosis stage (0.8 ± 0.80 vs 1.2 ± 0.91; P = 0.004), milder lobular inflammation (0.9 ± 0.7 vs 1.1 ± 0.7; P = 0.02), and significantly lower serum creatinine, total bilirubin, ferritin, and type IV collagen 7S and higher high‐density lipoprotein levels. After a median follow‐up of 8.9 years, no significant difference was noted in mortality between the two groups (2 [3.4%] non‐obese vs 5 [3.0%] obese; log‐rank test, P = 0.63). Twelve patients (20.7%) in the non‐obese group and 32 (19.4%) in the obese group had clinical events. Although the obese group had a higher incidence of clinical events during the first 10 years of follow‐up, the non‐obese group had a higher incidence after that (log‐rank test, P = 0.67). The non‐obese group had a high incidence of malignancy (9 [15.5%] non‐obese vs 14 [8.3%] obese; P = 0.13).

Conclusion

Non‐obese NAFLD does not necessarily have a good prognosis, and some cases have a poor prognosis such as extrahepatic cancers. Further validation is required in the future.

Non-alcoholic fatty liver disease-related fibrosis and sarcopenia: An altered liver-muscle crosstalk leading to increased mortality risk

In the last few decades, the loss of skeletal muscle mass and function, known as sarcopenia, has significantly increased in prevalence, becoming a major global public health concern. On the other hand, the prevalence of non-alcoholic fatty liver disease (NAFLD) has also reached pandemic proportions, constituting the leading cause of hepatic fibrosis worldwide. Remarkably, while sarcopenia and NAFLD-related fibrosis are independently associated with all-cause mortality, the combination of both conditions entails a greater risk for all-cause and cardiac-specific mortality. Interestingly, both sarcopenia and NAFLD-related fibrosis share common pathophysiological pathways, including insulin resistance, chronic inflammation, hyperammonemia, alterations in the regulation of myokines, sex hormones and growth hormone/insulin-like growth factor-1 signaling, which may explain reciprocal connections between these two disorders. Additional contributing factors, such as the gut microbiome, may also play a role in this relationship. In skeletal muscle, phosphatidylinositol 3-kinase/Akt and myostatin signaling are the central anabolic and catabolic pathways, respectively, and the imbalance between them can lead to muscle wasting in patients with NAFLD-related fibrosis. In this review, we summarize the bidirectional influence between NAFLD-related fibrosis and sarcopenia, highlighting the main potential mechanisms involved in this complex crosstalk, and we discuss the synergistic effects of both conditions in overall and cardiovascular mortality.

Impact of non-alcoholic fatty liver disease on the risk of sarcopenia: a nationwide multicenter prospective study

BACKGROUND AND AIMS

Despite the association between sarcopenia and non-alcoholic fatty liver disease (NAFLD), no study has evaluated the predictive role of NAFLD in sarcopenia. We investigated impact of NAFLD on the risk of low muscle mass (LMM) and low muscle strength (LMS) in a nationwide multicenter study.

METHODS

A total of 1595 community-dwelling people aged 70-84 years were followed for 2 years in the Korean Frailty and Aging Cohort Study. Muscle mass was estimated by dividing appendicular skeletal muscle mass (ASM) by body mass index (BMI). Muscle strength was measured as handgrip strength (HGS) divided by BMI. The sex-specific lowest quintiles of ASM/BMI and HGS/BMI of the study population were used as cutoffs for LMM and LMS, respectively. The risk of LMM and LMS were assessed according to hepatic steatosis index (HSI) and fatty liver index (FLI) quartiles.

RESULTS

As HSI quartiles increased, the LMM risk increased gradually, after adjusting for age, sex, lifestyle factors, comorbidities, and several causative factors (insulin resistance, inflammation, and vitamin D) (Q4 vs. Q1 OR [95% CI] 3.46 [2.23-5.35]). The increased risk of LMS was even higher according to HSI quartiles (Q4 vs. Q1 5.81 [3.67-9.21]). Multivariate analyses based on FLI showed similar results. People with NAFLD (HSI > 36) were at higher risk of developing LMM and LMS compared to those without (1.65 [1.19-2.31] and 2.29 [1.61-3.26], respectively).

CONCLUSIONS

The presence of NAFLD may predict future risk of LMM and LMS, with greater impact on LMS than on LMM.

Association Between Skeletal Muscle Mass and Severity of Steatosis and Fibrosis in Non-alcoholic Fatty Liver Disease

Background

Sarcopenia is known to be the risk factor of non-alcoholic fatty liver disease (NAFLD). However, studies evaluating the association of skeletal muscle mass (SMM) with liver fibrosis by transient elastography are limited. Here, we investigated the association of SMM with hepatic steatosis and fibrosis assessed in Chinese adults.

Methods

Patients who underwent liver ultrasonography at the Health Promotion Center of the First Affiliated Hospital of Nanjing Medical University between January 2020 to June 2021 were enrolled. We used transient elastography to evaluate the degree of hepatic fat and liver stiffness. Appendicular skeletal muscle mass was determined by bioelectrical impedance and was adjusted for body weight to derive the skeletal muscle mass index (SMI).

Results

Of 3,602 finally enrolled individuals, 1,830 had NAFLD and 1,772 did not have NAFLD. SMI gradually decreased as the severity of hepatic steatosis increased (40.47 ± 3.94% vs. 39.89 ± 3.57% vs. 39.22 ± 3.46% vs. 37.81 ± 2.84%, P < 0.001). Individuals with F3-F4 and F2 liver fibrosis groups had significantly lower SMI than individuals with F0-F1 stages (37.51 ± 3.19% vs. 38.06 ± 3.51% vs. 39.36 ± 3.38%, P < 0.001). As the SMI increased, the percentages of subjects with mild and severe NAFLD, and the percentages of subjects in F2 and F3-F4 stage were gradually decreased. SMI was independently associated with the severity of hepatic steatosis and fibrosis by logistic regression analysis. Moreover, decreased SMI was an independent risk factor for NAFLD and fibrosis.

Conclusion

SMI is closely associated with liver fat content and liver fibrosis in Chinese adults with NAFLD.

Impact of Sarcopenia on the Severity of the Liver Damage in Patients With Non-alcoholic Fatty Liver Disease

An extensive body of the literature shows a strong interrelationship between the pathogenic pathways of non-alcoholic fatty liver disease (NAFLD) and sarcopenia through the muscle-liver-adipose tissue axis. NAFLD is one of the leading causes of chronic liver diseases (CLD) affecting more than one-quarter of the general population worldwide. The disease severity spectrum ranges from simple steatosis to non-alcoholic steatohepatitis (NASH), cirrhosis, and its complications: end-stage chronic liver disease and hepatocellular carcinoma. Sarcopenia, defined as a progressive loss of the skeletal muscle mass, reduces physical performances, is associated with metabolic dysfunction and, possibly, has a causative role in NAFLD pathogenesis. Muscle mass is a key determinant of the whole-body insulin-mediated glucose metabolism and impacts fatty liver oxidation and energy homeostasis. These mechanisms drive the accumulation of ectopic fat both in the liver (steatosis, fatty liver) and in the muscle (myosteatosis). Myosteatosis rather than the muscle mass per se, seems to be closely associated with the severity of the liver injury. Sarcopenic obesity is a recently described entity which associates both sarcopenia and obesity and may trigger worse clinical outcomes including hepatic fibrosis progression and musculoskeletal disabilities. Furthermore, the muscle-liver-adipose tissue axis has a pivotal role in changes of the body composition, resulting in a distinct clinical phenotype that enables the identification of the "sarcopenic NAFLD phenotype." This review aims to bring some light into the complex relationship between sarcopenia and NAFLD and critically discuss the key mechanisms linking NAFLD to sarcopenia, as well as some of the clinical consequences associated with the coexistence of these two entities: the impact of body composition phenotypes on muscle morphology, the concept of sarcopenic obesity, the relationship between sarcopenia and the severity of the liver damage and finally, the future directions and the existing gaps in the knowledge.

Impact of Sarcopenia and Myosteatosis in Non-Cirrhotic Stages of Liver Diseases: Similarities and Differences across Aetiologies and Possible Therapeutic Strategies

Sarcopenia is defined as a loss of muscle strength, mass and function and it is a predictor of mortality. Sarcopenia is not only a geriatric disease, but it is related to several chronic conditions, including liver diseases in both its early and advanced stages. Despite the increasing number of studies exploring the role of sarcopenia in the early stages of chronic liver disease (CLD), its prevalence and the relationship between these two clinical entities are still controversial. Myosteatosis is characterized by fat accumulation in the muscles and it is related to advanced liver disease, although its role in the early stages is still under researched. Therefore, in this narrative review, we firstly aimed to evaluate the prevalence and the pathogenetic mechanisms underlying sarcopenia and myosteatosis in the early stage of CLD across different aetiologies (mainly non-alcoholic fatty liver disease, alcohol-related liver disease and viral hepatitis). Secondly, due to the increasing prevalence of sarcopenia worldwide, we aimed to revise the current and the future therapeutic approaches for the management of sarcopenia in CLD.

Sarcopenia modifies the associations of nonalcoholic fatty liver disease with all-cause and cardiovascular mortality among older adults

The contribution of nonalcoholic fatty liver disease (NAFLD) to all-cause and cardiovascular mortality remains controversial. Sarcopenia, a measure of muscle mass, strength and function, may identify which persons are most at risk for adverse effects of NAFLD. We aimed to test the hypothesis that sarcopenia modifies the associations between NAFLD and all-cause and cardiovascular mortality. A total of 2446 older adults (≥ 60 years) from the third National Health and Nutrition Examination Survey were enrolled. Their mortality data were linked to death certificates in the National Death Index. Sarcopenia was defined as having low skeletal muscle mass together with slow gait speed, which captures both muscle mass and muscle function. Ultrasound tests were used for the assessment of hepatic steatosis. During follow-up (median 16.8 years), 1530 older subjects died from any cause, of which 379 were cardiovascular-related. All-cause and cardiovascular mortality rates were 4.31 and 1.07 per 100 person-years, respectively. In a multivariate model, using participants without NAFLD and sarcopenia as the reference group, individuals with both NAFLD and sarcopenia had 1.69 times [95% confidence interval (CI) 1.23-2.31] and 2.17 times (95% CI 1.33-3.54) higher risks of all-cause and cardiovascular mortality, respectively. However, NAFLD persons without sarcopenia had hazard ratios for all-cause and cardiovascular mortality similar to those of the reference group. Sarcopenia modified the associations of NAFLD with all-cause and cardiovascular mortality. Sarcopenia may identify older adults who are at the highest risk for adverse outcomes associated with NAFLD.