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

Associations between non-insulin-based insulin resistance surrogate markers and liver-related outcomes in metabolic dysfunction-associated steatotic liver disease: a nationwide cohort study in South Korea

BACKGROUND

Insulin resistance (IR) is a crucial mechanism in the pathogenesis and clinical progression of metabolic dysfunction-associated steatotic liver disease (MASLD). This study aimed to examine the relationship between non-insulin-based IR surrogate markers and the incidence of liver-related outcomes in individuals with MASLD in a nationwide Korean cohort.

METHODS

A total of 66,334 individuals with MASLD who underwent a health examination between 1 January 2009 and 31 December 2010 were included in the study and followed until 31 December 2019, with a median follow-up period of 9.4 years. Hepatic steatosis was defined as a fatty liver index ≥ 30. The triglyceride-glucose (TyG) index, triglyceride-to-high-density lipoprotein cholesterol (TG/HDL) ratio, and metabolic score of IR (METS-IR) were employed as non-insulin-based IR surrogate markers. The MASLD groups were divided into four groups based on the non-insulin-based IR surrogate markers quartiles. The primary outcome was liver-related outcomes, as a composite of hepatocellular carcinoma and decompensated liver cirrhosis.

RESULTS

The MASLD group was 64.4% male (average age, 59.0 years). Using the lowest quartile (Q1) of the three non-insulin-based IR surrogate markers as a reference, a decrease in the adjusted hazard ratio for liver-related outcomes was observed from Q2 to Q4: (TyG: Q2 0.90 [95% confidence interval [CI]: 0.79-1.02], Q3 0.80 [95% CI: 0.70-0.91], Q4 0.80 [95% CI: 0.69-0.92]; TG/HDL: Q2 0.85 [95% CI: 0.75-0.97], Q3 0.81 [95% CI: 0.71-0.92], Q4 0.81 [95% CI: 0.71-0.93]; METS-IR: Q2 0.83 [95% CI: 0.73-0.95], Q3 0.80 [95% CI: 0.70-0.91], Q4 0.80 [95% CI: 0.70-0.92]).

CONCLUSIONS

A lower non-insulin-based IR surrogate marker in the MASLD group may be associated with an increased risk of liver-related outcomes. In the course of monitoring MASLD, metabolic alterations must be meticulously observed.

Impact of PNPLA3 in Lean Individuals and in Cryptogenic Steatotic Liver Disease

BACKGROUND

Although metabolic dysfunction-associated steatotic liver disease (MASLD) is strongly associated with obesity, around 20% of individuals with hepatic steatosis may nonetheless have normal body mass index, a condition often referred to as lean nonalcoholic fatty liver disease (NAFLD). Under the new nomenclature and definition of MASLD, lean NAFLD can be further divided into lean MASLD (when there is one or more cardiometabolic risk factors) and cryptogenic steatotic liver disease (when there is no cardiometabolic risk factor).

RESULTS

Current studies suggest that the at-risk PNPLA3 rs738409 variant is more common among individuals with lean NAFLD than their overweight and obese counterparts. However, even in this group, cardiometabolic risk factors are often required for the development of hepatic steatosis and liver injury. In the general population, PNPLA3 gene polymorphism is associated with an increased risk of MASLD, more severe liver histology (i.e., the presence of steatohepatitis and fibrosis) and future development of hepatocellular carcinoma and cirrhotic complications. Emerging data also suggest that individuals carrying the PNPLA3 GG genotype might have a greater reduction in hepatic steatosis and liver enzymes with lifestyle intervention and metabolic treatments, such as glucagon-like peptide-1 receptor agonists.

CONCLUSION

Studies have not specifically examined the impact of PNPLA3 in lean individuals.

Global prevalence, metabolic characteristics, and outcomes of lean-MAFLD: a systematic review and meta-analysis

BACKGROUND

Metabolic Dysfunction-Associated Fatty Liver disease (MAFLD) among lean individuals is increasingly recognized. We aimed to compare the prevalence, metabolic characteristics, and outcomes of lean vs overweight/obese-MAFLD patients.

METHODS

Databases of Embase, Medline, and Web of Science were searched from inception till October 2023. Only cohorts adhering to the lean-MAFLD criteria as defined by the international consensus statement were included.

RESULTS

In the pooled analysis of 10,013,382 individuals, the prevalence of lean-MAFLD in the general population was 1.94% (95% CI 1.10-3.39%, I2 = 98.7%). Lean and overweight/obese-MAFLD patients had similar metabolic characteristics for blood pressure, LDL, TG, blood glucose, and HbA1c. There was an increased incidence rate and likelihood for liver-related mortality for lean-MAFLD vs overweight/obese-MAFLD [1.33 per 1000 patient-years (95% CI 1.28-1.39) vs 0.76 (95% CI 0.25-2.28), (OR 3.56 (95% CI 3.45-3.67), p < 0.01). There were similar incidence rates and odds ratios between lean vs overweight/obese-MAFLD for: (1) all-cause mortality [10.08 per 1000 patient-years (95% CI 9.93-10.23) vs 8.94 per 1000 patient-years (95% CI 4.08-19.57), (OR 1.92 (95% CI 0.01-220.57), p = 0.33)]; (2) cardiovascular-related mortality [2.53 per 1000 patient-years (95% CI 0.65-9.96) vs 2.07 per 1000 patient-years (95% CI 0.80-5.39), (OR 1.91 (95% CI 0.02-142.76), p = 0.58)]; and (3) cancer-related mortality [3.42 per 1000 patient-years (95% CI 3.33-3.51) vs 3.15 per 1000 patient-years (95% CI 1.21-8.19), (OR 1.99 (95% CI 0.29-13.52), p = 0.13).

CONCLUSION

Lean-MAFLD patients have an equivalent metabolic burden compared to overweight/obese-MAFLD patients and thus a similar incidence rate of major extrahepatic complications. However, they have an increased risk of liver-related mortality.

Cardiovascular disease and metabolic dysfunction-associated steatotic liver disease: pathophysiology and diagnostic aspects

Metabolic dysfunction-associated steatotic liver disease (MASLD) can be interpreted as the hepatic expression of metabolic syndrome, which is estimated to affect 30% of the adult population. Obesity, dyslipidaemia, arterial hypertension, and T2DM are considered significant risk factors of MASLD. The relationship is two-way with MASLD found in up to 75% of patients with T2DM. Importantly, MASLD is associated with increased risk of cardiovascular diseases (CVD) such as arrhythmia, atherosclerotic heart disease, heart failure, and CVD-associated mortality. In addition, MASLD patients present with a high prevalence of major adverse cardiac events, which calls for systematic surveillance of CVD in MASLD. This review focuses on the pathophysiology behind development of CVD in MASLD, the types of cardiovascular complications, morbidity and survival, and suggestions for evaluation of patients with MASLD.

Impact of PNPLA3 I148M on Clinical Outcomes in Patients With MASLD

BACKGROUND AND AIMS

Metabolic dysfunction-associated steatotic liver disease (MASLD) is a heterogenous clinical and histopathological entity, where multiple metabolic co-factors are intertwined with high interindividual variability. The impact and severity of each factor (including obesity and type 2 diabetes) define a systemic dysmetabolism that can lead to either advanced liver disease and its complication (including hepatocellular carcinoma and clinical events related to portal hypertension) or extrahepatic events: incident cardiovascular disease, chronic kidney disease and extrahepatic cancers. The balance between environmental factors and genetic susceptibility has unique implications in MASLD: the intermittent injury of metabolic co-factors, their fluctuation over time and their specific management, are counterbalanced by the presence of gene variants that can significantly impact the disease at multiple levels. The I148M variant in the PNPLA3 gene is the most investigated genetic susceptibility that induces a more severe steatohepatitis, enhanced fibrogenesis and can shape the incidence of long-term clinical events regardless of, or worsened by, other metabolic risk factors.

METHODS AND RESULTS

In this review, we will summarise the updated evidence on the natural history of MASLD accounting for classical metabolic risk factors, the role of PNPLA3 in clinical sub-phenotyping (e.g., 'lean MASLD'), impact on disease severity and fibrosis progression, as well as its role for prognostication, alone or in combination with non-invasive tools into polygenic risk scores.

Mortality risk associated with MASLD, MASLD type and different cardiometabolic risk factors in IBD patients: A long-term prospective cohort study

PURPOSE

To examine the mortality risk associated with metabolic dysfunction-associated steatotic liver disease (MASLD), MASLD type, lean/non-lean MASLD and different cardiometabolic risk factors (CMRFs) in patients with inflammatory bowel disease (IBD) based on a long-term prospective cohort.

METHODS

Prevalent IBD patients at baseline who were free of alcoholic liver disease, cancer and hepatitis B/C virus seropositive were included (N=4622). MASLD, MASLD type [pure MASLD, MASLD with increased alcohol intake (MetALD)], lean/non-lean MASLD and CMRFs at baseline were defined according to the latest criteria proposed by AASLD and EASL. Primary outcome was all-cause mortality. Cox proportional hazard model was used to examine the association.

RESULTS

Overall, 1,763 (38.1%) were diagnosed with MASLD. During a median of 13.3-year follow-up, 451 all-cause deaths were identified. Compared with IBD-only patients, those with MASLD had a 58% excess risk of mortality (HR=1.58, 95%CI:1.07-2.32). Furthermore, as number of CMRFs increased in MASLD patients, mortality risk was significantly increased (Ptrend=0.005), with a 85% and 83% higher risk in MASLD with 3 CMRFs (HR=1.85, 95%CI:1.20-2.85) and ≥4 CMRFs (HR=1.83, 95%CI:1.16-2.89) versus IBD-only patients. Specifically, similar elevated mortality risk was observed in either pure MASLD (HR= 1.62, 95%CI:1.09-2.43) or MetALD (HR=2.03, 95%CI:1.24-3.32). Moreover, the excess mortality risk was both indicated in lean (HR=3.14, 95%CI:1.57-6.29) and non-lean MASLD (HR=1.67, 95%CI:1.12-2.48).

CONCLUSIONS

MASLD, either pure MASLD or MetALD, as well as lean/non-lean MASLD, is associated with increased mortality risk in IBD patients, with greater risk as number of cardiometabolic risk factors increased and evidently higher risk in lean MASLD patients.

Lean Metabolic Dysfunction-Associated Steatotic Liver Disease: A Comparative Analysis of Hepatic and Oncological Outcomes

GOALS

To compare outcomes of MASLD in obese and nonobese populations.

BACKGROUND

MASLD is emerging as one of the leading causes of liver failure and liver-related morbidity and mortality, with an increasing prevalence in the nonobese or lean population. The purpose of this study is to compare hepatic and oncological outcomes between MASLD patients with lean BMI and nonlean BMI.

STUDY

The National Inpatient Sample (NIS) was queried from 2016 to 2020 for adult hospitalizations with MASLD. Exclusion criteria included concurrent diagnoses of viral hepatitis, alcoholic hepatitis, primary biliary cholangitis, hereditary hemochromatosis, autoimmune hepatitis, or Wilson disease. Outcomes of MASLD and its complications were compared between the lean and nonlean subgroups.

RESULTS

Patients with lean BMI had higher mortality rates (odds ratio: 2.10, P<0.001). The lean cohort also had higher odds of cirrhosis, portal hypertension, SBP, and ascites. The lean subgroup had higher odds of gastrointestinal malignancies including esophageal cancer, gastric cancer, pancreatic cancer, and colorectal cancer.

CONCLUSIONS

Hospitalized lean MASLD patients had higher odds of mortality, ​​hepatic morbidities, and gastrointestinal malignancies. These results challenge the use of BMI as a predictor of morbidity and mortality for MASLD patients. Future studies should focus on therapeutic options for MASLD and compare their efficacies between lean and nonlean populations.

Clinical Variables that Predict Liver-related Events in Steatotic Liver Disease Diagnosed by a Liver Biopsy

Objective Identifying patients at high risk of steatotic liver disease (SLD) is crucial. The liver fibrosis stage is the most reliable marker of liver-related mortality. However, noninvasive risk stratification methods remain controversial. Therefore, we analyzed the risk of liver-related events in patients who underwent a liver biopsy for metabolic dysfunction-associated steatotic liver disease (MASLD) or cryptogenic SLD at our hospital. Methods We retrospectively reviewed the clinical course of the patients to identify the occurrence of liver-related events. Patients This study included 146 patients diagnosed with SLD through a liver biopsy. Results Liver-related events occurred in 20 patients and were more frequent in those with advanced fibrosis than in those without advanced fibrosis. However, patients with advanced steatosis exhibit reduced disease progression. Patients with obesity and/or diabetes complications had a lower stage of fibrosis and better prognosis than the others. The non-invasive fibrosis-4 (FIB-4) index and non-alcoholic fatty liver disease (NAFLD) prognosis-related "NAFLD outcomes score (NOS)" effectively differentiated patients with disease progression. Standard laboratory data analyses revealed that high total bilirubin and low albumin levels were risk factors. A multivariate analysis with significant factors other than NOS score revealed that the absence of obesity and/or diabetes complications, a high FIB-4 index, and a high total bilirubin level were independent factors for liver-related events. Conclusion A high NOS score, absence of obesity and/or diabetes complications, a high FIB-4 index, and high total bilirubin levels are risk factors for disease progression. Patients with lean phenotypes or non-diabetic SLD should also be assessed using noninvasive markers to determine their risks and potential outcomes.

The dynamic patterns of metabolic-associated fatty liver disease and its severity and risk of cardiovascular disease

BACKGROUND

While metabolic-associated fatty liver disease (MAFLD) is widely recognized as a risk factor for cardiovascular disease (CVD), the connection between the dynamic patterns of severity of hepatic steatosis and the associated CVD risk remains uncertain.

METHOD

This study included 71,098 participants from the Kailuan Study without CVD or cancer who underwent two consecutive biennial health screenings between 2006 and 2008 and were followed up until 2022. MAFLD and its severity were assessed using ultrasound. Participants were categorized into four groups based on dynamic MAFLD patterns: MAFLD-free, MAFLD-progression, MAFLD-regression, and MAFLD-persistence. MAFLD-regression was further divided into regression from mild MAFLD and regression from moderate/severe MAFLD. Cox proportional hazard regression models analyzed the association between the progression and regression of MAFLD and CVD risk.

RESULT

After a mean follow-up of 12.63 ± 3.16 years, 7838 individuals experienced incident CVD, 5374 had strokes, 1321 had myocardial infarctions, and 1819 developed heart failure. After adjusting for potential confounders, MAFLD-progression was associated with a higher CVD risk compared to MAFLD-free (HR 1.25, 95% CI 1.17-1.33), but this risk decreased with increasing age. Individuals with MAFLD-persistence had the highest CVD risk (HR 1.54, 95% CI 1.46-1.62). Compared to persistent MAFLD, regression from mild MAFLD was associated with a lower CVD risk (HR 0.83, 95% CI 0.76-0.91).

CONCLUSION

The progression of MAFLD can increase the risk of CVD, while regression of MAFLD can decrease the risk of CVD. These findings suggest that the dynamic patterns of MAFLD significantly influence CVD risk.

Incidence of metabolic dysfunction-associated steatotic liver disease and advanced fibrosis and impact of overweight/obesity in elderly population: a nationwide cohort study

BACKGROUND AND AIM

The prevalence of metabolic dysfunction-associated steatotic liver disease (MASLD) is increasing worldwide, coinciding with aging population. However, limited studies have evaluated its incidence and progression to advanced fibrosis in the elderly population. Therefore, our study aimed to investigate the incidence of MASLD and advanced fibrosis in this age group.

METHODS

We included 878 686 individuals aged ≥60 years from the Korea National Health Insurance Service-Senior cohort. After excluding participants with preexisting MASLD, 329 388 individuals were finally analyzed. Participants were categorized into four groups based on the presence of overweight/obesity and additional risk factors (aRF) included in the cardiometabolic diagnostic criteria of MASLD.

RESULTS

The overall incidence of MASLD was 1.94 per 100 person-years, and the incidence of advanced fibrosis in MASLD patients was 1.78 per 100 person-years. MASLD development was significantly higher in overweight/obese patients (2.65 per 100 person-years) compared to lean patients (1.09 per 100 person-years), and this trend persisted after stratification by the presence of aRF. Similarly, the incidence of advanced fibrosis among MASLD patients was higher in overweight/obese individuals (2.06 per 100 person-years) compared to lean counterparts (0.87 per 100 person-years), irrespective of aRF.

CONCLUSIONS

The lower incidence of MASLD in the elderly population compared to the general population underscores the importance of identifying age-specific risk factors. Overweight/obesity emerged as a robust predictor of MASLD development and advanced fibrosis. Additionally, the presence of additional cardiometabolic risk factors further increased the risk of incident MASLD and advanced fibrosis among the elderly.

Propylthiouracil Induced Rat Model Reflects Heterogeneity Observed in Clinically Non-Obese Subjects with Nonalcoholic Fatty Liver Disease

The prevalence of nonalcoholic fatty liver disease (NAFLD) is increasing, affecting up to 30% of the population, with approximately 20% of cases occurring in non-obese individuals. The recent shift to the term metabolic dysfunction-associated steatosis liver disease (MASLD) highlights the disease's heterogeneity. However, there are no well-established animal models replicating non-obese NAFLD (NO-NAFLD). This study aimed to evaluate the relevance of the high-fat diet (HFD) combined with the propylthiouracil (PTU)-induced rat model in mimicking the histopathology and pathophysiology of NO-NAFLD. We first analyzed metabolic and clinical parameters between NO-NAFLD patients (Average BMI = 21.96 kg/m2) and obese NAFLD patients (Average BMI = 29.7 kg/m2). NO-NAFLD patients exhibited significantly higher levels of carnitines, phospholipids, and triglycerides. In the animal model, we examined serum lipid profiles, liver inflammation, histology, and transcriptomics. Hepatic steatosis in the HFD+PTU model at week 4 was comparable to that of the HFD model at week 8. The HFD+PTU model showed higher levels of carnitines, phospholipids, and triglycerides, supporting its relevance for NO-NAFLD. Additionally, the downregulation of lipid synthesis-related genes indicated differences in lipid accumulation between the two models. Overall, the HFD+PTU-induced rat model is a promising tool for studying the molecular mechanisms of NO-NAFLD.

An insight into the updated pharmacotherapy of metabolic-associated fatty liver disease (MAFLD) or metabolic dysfunction-associated steatohepatitis (MASH) in lean individuals: a review

Metabolic-associated fatty liver disease (MAFLD) or metabolic dysfunction-associated steatohepatitis (MASH) in lean individuals represents a distinctive subset of MASH. Current pharmacotherapies, for MASH as demonstrated in clinical trials, predominantly target obese patients with limited consideration for lean MASH. We aimed to systematically review the literature on the pharmacotherapy of lean MASH. We searched standard medical databases, such as PubMed, Embase, Scopus, Cochrane CENTRAL, and ClinicalTrials.gov to identify eligible studies published in English up to 31 December 2023 regarding the effect of pharmacological interventions in individuals with lean MASH. We have summarized the role of various drug classes including peroxisome proliferator-activated receptor agonists, glucagon-like peptide-1 receptor agonists, sodium-glucose cotransporter 2 inhibitors, vitamin E, farnesoid X receptor agonists, selective thyroid hormone receptor-β agonists, and selective cholesterol absorption inhibitors. Consequently, lifestyle interventions, encompassing dietary modifications, exercise, and weight loss particularly directed at visceral obesity or achieving a reduction in body weight are recommended for all non-obese individuals with MASH. A highlight on the only available treatment recommendation for lean MASH is also presented. The available evidence regarding the efficacy of various drugs for the treatment of lean MASH is limited. Conclusive evidence is warranted from clinical trials exclusively involving lean individuals with MASH.

Liver and cardiovascular outcomes in lean non-alcoholic fatty liver disease: an updated systematic review and meta-analysis of about 1 million individuals

BACKGROUND AND AIMS

Non-alcoholic fatty liver disease (NAFLD) is present in lean people. However, the magnitude of the prognostic hepatic and cardiovascular risk in these patients compared to non-lean counterparts remains unclear. We aimed to investigate this topic, and to explore whether these risks change based on factors related to NAFLD severity.

METHODS

PubMed and Embase databases were searched for cohort studies (published through April 2024) that evaluated liver and cardiovascular (CV) outcomes in lean and non-lean individuals with NAFLD and reported unadjusted or adjusted data. We pooled risk ratios (RRs) or hazard ratios (HRs) using a random-effects modeling and performed subgroup and meta-regressions analyses.

RESULTS

We identified 22 studies with over 1 million NAFLD patients (13.0% were lean). Lean NAFLD showed a similar risk of liver-related events in unadjusted analysis (RR 1.08, 95% CI 0.79-1.49, I2 = 31%), but a higher risk in adjusted analysis (HR 1.66, 95% CI 1.17-2.36, I2 = 83%) compared to non-lean NAFLD. Lean NAFLD had a higher risk of liver-related mortality (RR 2.22, 95% CI 1.57-3.15, I2 = 0%; HR 2.26, 95% CI 1.14-4.51, I2 = 0%). For CV outcomes, lean NAFLD had a lower risk of any cardiovascular disease in unadjusted analysis (RR = 0.82, 95% CI 0.70-0.95, I2 = 88%), but similar risk in adjusted analysis (HR 0.89, 95% CI 0.77-1.02, I2 = 78%), and similar risk of cardiovascular mortality (RR 1.09, 95% CI 0.71-1.66, I2 = 85%; HR 1.26, 95% CI 0.89-1.78, I2 = 46%) compared to non-lean NAFLD.

CONCLUSIONS

Lean NAFLD patients have worse liver outcomes, but similar CV outcomes compared to non-lean NAFLD patients, highlighting the importance of monitoring both groups closely.

Metabolic dysfunction associated fatty liver disease in healthy weight individuals

Metabolic dysfunction associated fatty liver disease (MAFLD) is an increasing public health problem, affecting one third of the global population. Contrary to conventional wisdom, MAFLD is not exclusive to obese or overweight individuals. Epidemiological studies have revealed a remarkable prevalence among healthy weight individuals, leading investigations into the genetic, lifestyle, and dietary factors that contribute to the development of MAFLD in this population. This shift in perspective requires reconsideration of preventive strategies, diagnostic criteria and therapeutic approaches tailored to address the unique characteristics of MAFLD healthy weight individuals. It also underscores the importance of widespread awareness and education, within the medical community and among the general population, to promote a more inclusive understanding of liver metabolic disorders. With this review, we aim to provide a comprehensive exploration of MAFLD in healthy weight individuals, encompassing epidemiological, pathophysiological, and clinical aspects.

Diagnosis and Management of Lean Metabolic Dysfunction-Associated Steatotic Liver Disease (MASLD): A Systematic Review

Lean metabolic dysfunction-associated steatotic liver disease (MASLD) defies traditional views of fatty liver diseases by manifesting in nonobese individuals. The renaming from nonalcoholic fatty liver disease to MASLD underscores a broader understanding of its pathophysiology, highlighting the complex interplay of metabolic factors beyond obesity. Despite its clinical importance, diagnosing and managing lean MASLD remains challenging due to its historical ties to obesity and a general lack of awareness about its unique characteristics. On December 4, 2023, a systematic literature search was conducted across six databases, focusing on peer-reviewed studies in English related to the diagnosis and management of lean MASLD. This study was registered with the International Prospective Register of Systematic Reviews (CRD42023489308). Out of 95 studies following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, 43 addressed diagnosis and surveillance, whereas 52 explored management strategies. The results revealed the difficulties in diagnosing lean MASLD, pointing out the limitations of traditional markers and the potential of advanced imaging techniques. Management strategies discussed included lifestyle changes and possible pharmacological treatments tailored to the specific metabolic features of this patient group. The study highlights the necessity for increased clinical awareness, regular monitoring, and personalized therapeutic approaches for lean MASLD. It calls for further research to refine diagnostic criteria and develop targeted treatments, aiming to enhance care for individuals with lean MASLD.

Weight-adjusted waist index is positively and linearly associated with all-cause and cardiovascular mortality in metabolic dysfunction-associated steatotic liver disease: findings from NHANES 1999-2018

BACKGROUND

Metabolic dysfunction-associated steatotic liver disease (MASLD) is the most common chronic liver disease. Body mass index (BMI) is the most used obesity index but has important limitations. The weight-adjusted waist index (WWI) is a novel obesity metric and accurately reflects body composition. We explored the association of WWI with all-cause and cardiovascular disease (CVD) mortality in MASLD.

METHODS

Adult participants with MASLD were included from NHANES 1999-2018. WWI was calculated by dividing the waist circumference (WC) by the square root of body weight. MASLD was diagnosed by the presence of hepatic steatosis and at least one cardiometabolic risk factor in the absence of other causes of steatosis. A fatty liver index ≥60 suggested the presence of hepatic steatosis. Mortality data was obtained by prospectively linking to the National Death Index. Multivariate Cox proportional hazards regression analyses were used to explore these associations and multiple adjustment models were constructed including crude, partial, and fully adjusted models.

RESULTS

After adjusting for all covariates including BMI, WWI remained positively and linearly associated with all-cause and CVD mortality in MASLD (hazard ratios [HR] 1.247 and 1.218, respectively). Higher WWI was associated with a significantly increased risk of mortality (both p for trend <0.05). There was an "obesity paradox" between BMI and all-cause mortality in MASLD, with significantly lower all-cause mortality in those with overweight/obesity compared to normal BMI (HR 0.625 and 0.596, respectively, p for trend = 0.024), and no association between BMI and CVD mortality. Interaction analyses indicated that these associations were influenced by several demographic variables and disease status. Time-dependent receiver operating characteristic curves indicated that the predictive value of WWI for mortality in MASLD was higher than that of BMI, WC, and waist-to-height ratio across all follow-up durations.

CONCLUSIONS

WWI was positively and linearly associated with all-cause and CVD mortality in MASLD, whereas BMI did not accurately reflect mortality risk. WWI provided the optimal predictive value for mortality compared to traditional obesity indicators. These findings emphasize the potential use of WWI as a novel obesity indicator for mortality risk assessment, stratification, and prevention in MASLD.

Long-term outcomes following hepatectomy in patients with lean non-alcoholic fatty liver disease-associated hepatocellular carcinoma versus overweight and obese counterparts: A multicenter analysis

BACKGROUND & AIMS

With the rising prevalence of non-alcoholic fatty liver disease (NAFLD) as a significant etiology for hepatocellular carcinoma (HCC), lean NAFLD-HCC has emerged as a specific distinct subtype. This study sought to investigate long-term outcomes following curative-intent hepatectomy for early-stage NAFLD-HCC among lean patients compared with overweight and obese individuals.

METHODS

A multicenter retrospective analysis was used to assess early-stage NAFLD-HCC patients undergoing curative-intent hepatectomy between 2009 and 2022. Patients were stratified by preoperative body mass index (BMI) into the lean (<23.0 kg/m2), overweight (23.0-27.4 kg/m2) and obese (≥27.5 kg/m2) groups. Study endpoints were overall survival (OS) and recurrence-free survival (RFS), which were compared among groups.

RESULTS

Among 309 patients with NAFLD-HCC, 66 (21.3 %), 176 (57.0 %), and 67 (21.7 %) were lean, overweight, and obese, respectively. The three groups were similar relative to most liver, tumor, and surgery-related variables. Compared with overweight patients (71.3 % and 55.6 %), the lean individuals had a worse 5-year OS and RFS (55.4 % and 35.1 %, P = 0.017 and 0.002, respectively), which were comparable to obese patients (48.5 % and 38.2 %, P = 0.939 and 0.442, respectively). After adjustment for confounding factors, multivariable Cox-regression analysis identified that lean bodyweight was independently associated with decreased OS (hazard ratio: 1.69; 95 % confidence interval: 1.06-2.71; P = 0.029) and RFS (hazard ratio: 1.72; 95 % confidence interval: 1.17-2.52; P = 0.006) following curative-intent hepatectomy for early-stage NAFLD-HCC.

CONCLUSIONS

Compared with overweight patients, individuals with lean NAFLD-HCC had inferior long-term oncological survival after hepatectomy for early-stage NAFLD-HCC. These data highlight the need for examination of the distinct carcinogenic pathways of lean NAFLD-HCC and its potential consequences in HCC recurrence.

Cardiovascular morbidity and mortality in lean vs. non-lean MASLD: A comprehensive meta-analysis

BACKGROUND

Lean metabolic dysfunction-associated steatotic liver disease (MASLD), characterized by a BMI < 25 kg/m² (or < 23 kg/m² in Asians), presents a challenging prognosis compared to non-lean MASLD. This study examines cardiovascular outcomes in both lean and non-lean MASLD cohorts.

METHODS

In this meta-analysis, pooled odds ratios (ORs) within 95 % confidence intervals (CIs) were calculated for primary outcomes (cardiovascular mortality and major adverse cardiovascular events [MACE]) and secondary outcomes (cardiovascular disease [CVD], all-cause mortality, hypertension, and dyslipidemia). Studies comparing lean and non-lean MASLD within the same cohorts were analyzed, prioritizing those with larger sample sizes or recent publication dates.

RESULTS

Twenty-one studies were identified, encompassing lean MASLD patients (n = 7153; mean age 52.9 ± 7.4; 56 % male) and non-lean MASLD patients (n = 23,514; mean age 53.2 ± 6.8; 63 % male). Lean MASLD exhibited a 50 % increase in cardiovascular mortality odds compared to non-lean MASLD (OR: 1.5, 95 % CI 1.2-1.8; p < 0.0001). MACE odds were 10 % lower in lean MASLD (OR: 0.9, 95 % CI 0.7-1.2; p = 0.7), while CVD odds were 40 % lower (p = 0.01). All-cause mortality showed a 40 % higher odds in lean MASLD versus non-lean MASLD (p = 0.06). Lean MASLD had 30 % lower odds for both hypertension (p = 0.01) and dyslipidemia (p = 0.02) compared to non-lean MASLD.

CONCLUSION

Despite a favorable cardiometabolic profile and comparable MACE rates, lean individuals with MASLD face elevated cardiovascular mortality risk.

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.

Disparities among ethnic groups in mortality and outcomes among adults with MASLD: A multicenter study

BACKGROUND

Metabolic dysfunction-associated steatotic liver disease (MASLD) is the leading cause of chronic liver disease and 10%-20% occurs in lean individuals. There is little data in the literature regarding outcomes in an ethnically-diverse patient populations with MASLD. Thus, we aim to investigate the natural history and ethnic disparities of MASLD patients in a diverse population, and stratified by body mass index categories.

METHODS

We conducted a retrospective multicenter study on patients with MASLD at the Banner Health System from 2012 to 2022. Main outcomes included mortality and incidence of cirrhosis, cardiovascular disease, diabetes mellitus (DM), liver-related events (LREs), and cancer. We used competing risk and Cox proportional hazard regression analysis for outcome modelling.

RESULTS

A total of 51 452 (cross-sectional cohort) and 37 027 (longitudinal cohort) patients were identified with 9.6% lean. The cohort was 63.33% European ancestry, 27.96% Hispanic ancestry, 3.45% African ancestry, and 2.31% Native American/Alaskan ancestry. Median follow-up was 45.8 months. After adjusting for confounders, compared to European individuals, Hispanic and Native American/Alaskan patients had higher prevalence of cirrhosis and DM, and individuals of Hispanic, African, and Native American/Alaskan ancestry had higher mortality and incidence of LREs and DM. Lean patients had higher mortality and incidence of LREs compared with non-lean patients.

CONCLUSION

Native American/Alaskan, Hispanic, and African patients had higher mortality and incidence of LREs and DM compared with European patients. Further studies to explore the underlying disparities and intervention to prevent LREs in lean patients, particularly several ethnic groups, may improve clinical outcomes.

MAFLD: an ideal framework for understanding disease phenotype in individuals of normal weight

The prevalence of metabolic dysfunction-associated fatty liver disease (MAFLD) is significant, impacting almost one-third of the global population. MAFLD constitutes a primary cause of end-stage liver disease, liver cancer and the need for liver transplantation. Moreover, it has a strong association with increased mortality rates due to various extrahepatic complications, notably cardiometabolic diseases. While MAFLD is typically correlated with obesity, not all individuals with obesity develop the disease and a significant percentage of MAFLD occurs in patients without obesity, termed lean MAFLD. The clinical features, progression and underlying physiological mechanisms of patients with lean MAFLD remain inadequately characterized. The present review aims to provide a comprehensive summary of current knowledge on lean MAFLD and offer a perspective on defining MAFLD in individuals with normal weight. Key to this process is the concept of metabolic health and flexibility, which links states of dysmetabolism to the development of lean MAFLD. This perspective offers a more nuanced understanding of MAFLD and its underlying mechanisms and highlights the importance of considering the broader metabolic context in which the disease occurs. It also bridges the knowledge gap and offers insights that can inform clinical practice.

Mortality, Hepatic Decompensation, and Cardiovascular- and Renal-Related Outcomes in Lean Versus Non-lean Patients Hospitalized With Metabolic Dysfunction-Associated Steatohepatitis (MASH)

INTRODUCTION

Metabolic dysfunction-associated steatohepatitis (MASH) is an important cause of cirrhosis and end-stage liver disease. In addition, there have been reports of worse extrahepatic outcomes, especially cardiovascular events, in patients with lean patients' fatty liver disease compared to the non-lean group. There is limited data on hepatic, cardiac, and renal outcomes in lean compared to non-lean patients with MASH. This study aims to evaluate the cardiovascular, renal, and hepatic outcomes in hospitalized US adults with MASH, focusing on a comprehensive comparison between lean and non-lean patients.

METHODS

The National Inpatient Sample (NIS) database was queried from 2016 to 2020 to identify hospitalizations with MASH. Hospitalizations with a history of overweight and obesity (lean body mass index (BMI) <25 vs. lean BMI >25) were also identified. The primary outcome was in-hospital mortality. Secondary outcomes were major adverse cardiovascular outcomes (MACE: a composite of acute myocardial infarction, cardiac arrest, stroke, heart failure, and atrial fibrillation); major adverse kidney outcome (MAKE: a composite outcome of acute kidney injury (AKI), renal replacement therapy, and renal cancer), and hepatic decompensation (esophageal varices with bleeding, ascites, spontaneous bacterial peritonitis (SBP), hepatic encephalopathy, and hepatorenal syndrome) Multivariate logistic regression analysis was used to derive risk ratios for clinical outcomes.

RESULTS

We included 539,275 MASH patients in our sample; 324,330 (60%) were lean. The included patients were mostly female (61%), the mean age was 64 years, and 76% were White. At baseline, non-lean patients had a higher prevalence of heart failure, hypertension, and hyperlipidemia. There was no difference in the prevalence of smoking among both groups. In a multivariate analysis, with adjustment for age, sex, race, sarcopenia, cardiometabolic risk factors, hospital characteristics, admission type, socioeconomic factors, and all comorbidities (including 31 Elixhauser comorbidities), lean status was associated with a 40% increased risk of mortality (adjusted odds ratio (aOR) 1.40, confidence interval (CI) 1.29-1.53), 19% increased risk of MACE (aOR 1.19; 95% CI 1.14-1.24), 20% increased risk of renal decompensation (aOR 1.25; 95% CI 1.20-1.30), and 33% increased risk of hepatic decompensation (aOR 1.33 CI 1.28-1.38).

CONCLUSION

Lean patients with MASH are at higher risk of cardiovascular and renal outcomes and may benefit from enhanced screening for early identification and treatment to improve outcomes.

Hepatic Fibrosis and Cancer: The Silent Threats of Metabolic Syndrome

Metabolic dysfunction-associated steatotic (fatty) liver disease (MASLD), previously termed non-alcoholic fatty liver disease, is a worldwide epidemic that can lead to hepatic inflammation, fibrosis, cirrhosis, and hepatocellular carcinoma (HCC). The disease is typically a component of the metabolic syndrome that accompanies obesity, and is often overlooked because the liver manifestations are clinically silent until late-stage disease is present (i.e., cirrhosis). Moreover, Asian populations, including Koreans, have a higher fraction of patients who are lean, yet their illness has the same prognosis or worse than those who are obese. Nonetheless, ongoing injury can lead to hepatic inflammation and ballooning of hepatocytes as classic features. Over time, fibrosis develops following activation of hepatic stellate cells, the liver's main fibrogenic cell type. The disease is usually more advanced in patients with type 2 diabetes mellitus, indicating that all diabetic patients should be screened for liver disease. Although there has been substantial progress in clarifying pathways of injury and fibrosis, there no approved therapies yet, but current research seeks to uncover the pathways driving hepatic inflammation and fibrosis, in hopes of identifying new therapeutic targets. Emerging molecular methods, especially single cell sequencing technologies, are revolutionizing our ability to clarify mechanisms underlying MASLD-associated fibrosis and HCC.

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.

Gut Microbiota in Patients with Non-Alcoholic Fatty Liver Disease without Type 2 Diabetes: Stratified by Body Mass Index

The relationship between gut dysbiosis and body mass index (BMI) in non-diabetic patients with non-alcoholic fatty liver disease (NAFLD) is not adequately characterized. This study aimed to assess gut microbiota's signature in non-diabetic individuals with NAFLD stratified by BMI. The 16S ribosomal RNA sequencing was performed for gut microbiota composition in 100 patients with NAFLD and 16 healthy individuals. The differential abundance of bacterial composition between groups was analyzed using the DESeq2 method. The alpha diversity (Chao1, Shannon, and observed feature) and beta diversity of gut microbiota significantly differed between patients with NAFLD and healthy controls. However, significant differences in their diversities were not observed among subgroups of NAFLD. At the phylum level, there was no trend of an elevated Firmicutes/Bacteroidetes ratio according to BMI. At the genus level, patients with lean NAFLD displayed a significant enrichment of Escherichia-Shigella and the depletion of Lachnospira and Subdoligranulum compared to the non-lean subgroups. Combining these bacterial genera could discriminate lean from non-lean NAFLD with high diagnostic accuracy (AUC of 0.82). Non-diabetic patients with lean NAFLD had a significant difference in bacterial composition compared to non-lean individuals. Our results might provide evidence of gut microbiota signatures associated with the pathophysiology and potential targeting therapy in patients with lean NAFLD.

Prevalence Study of MASLD in Adolescent and Young Adult Pacific Islanders and Asians Living in Hawai'i

Context

Nonalcoholic fatty liver disease, renamed metabolic dysfunction-associated steatotic liver disease (MASLD), is the most common cause of chronic liver disease with an estimated worldwide prevalence of 30.1% while clinical practice observations reflect a disproportionately lower prevalence of 1.9%, indicating a condition that is underrecognized in clinical care settings. Screening for MASLD is rarely performed, and little is known about the prevalence in Hawai'i.

Objective

This pilot aims to develop an understanding of the prevalence and factors associated with MASLD in Hawai'i's adolescent and young adult (AYA) population.

Design/Methods

Cross-sectional observational pilot study: We used Fibroscan®-liver ultrasonographic vibration-controlled transient elastography (VCTE) to identify MASLD based on controlled attenuation parameter (CAP) scores ≥238 (dB/m) and collected biometric, anthropometric, and Beverage Intake Questionnaire (sugar-sweetened beverage) survey data.

Setting

The study took place at community clinics in Hawai'i on the island of O'ahu.

Participants

One hundred individuals were evaluated, age 14 to 34 years.

Main Outcome Measures

We used VCTE Fibroscan® with CAP scoring to identify the presence of hepatocyte steatosis (fatty liver).

Results

Overall MASLD prevalence in the sample was 44% (95% confidence interval: 34.1%-54.3%). In participants with MASLD, obese Native Hawaiian and other Pacific Islanders (62%) and nonobese Asians (43%) had the highest rates of MASLD.

Conclusion

This pilot evaluation of the AYA NHOPI and Asian MASLD population in Hawai'i shows a higher rate of MASLD than those reported in other parts of the United States. Larger population health studies are indicated to expand our knowledge of MASLD in the Hawaiian Islands.

Gastrointestinal cancers in lean individuals with non-alcoholic fatty liver disease: A systematic review and meta-analysis

BACKGROUND & AIMS

Obesity and non-alcoholic fatty liver disease (NAFLD) are known risk factors for gastrointestinal (GI) cancers. However, GI carcinogenesis in lean NAFLD patients remains unclear. This systematic review and meta-analysis aims to investigate the association between lean NAFLD and GI cancer risk.

METHODS

PubMed, Embase and Cochrane Library databases were systematically searched (from inception date to April 2023) for cohort studies assessing GI cancers in lean (body mass index [BMI] < 25 kg/m2 or < 23 kg/m2 in Asians) and non-lean (BMI ≥25 kg/m2 or ≥ 23 kg/m2 in Asians) NAFLD individuals. Data from eligible studies were extracted, and meta-analysis was carried out using a random effects model to obtain risk ratios (RRs) with 95% confidence intervals (CIs). Subgroup analyses, meta-regressions and sensitivity analyses were also performed. This study was registered in PROSPERO (CRD42023420902).

RESULTS

Eight studies with 56,745 NAFLD individuals (11% were lean) and 704 cases of incident GI cancers were included. Lean NAFLD was associated with higher risk of hepatic (RR 1.77, 95% CI 1.15-2.73), pancreatic (RR 1.97, 95% CI 1.01-3.86) and colorectal cancers (RR 1.53, 95% CI 1.12-2.09), compared to non-lean NAFLD. No significant differences were observed for oesophagus, gastric, biliary and small intestine cancers.

CONCLUSIONS

This study shows that lean NAFLD patients have an increased risk of liver, pancreatic and colorectal cancers compared to non-lean NAFLD patients, emphasizing the need to explore tailored cancer prevention strategies for this specific patient group. Further research is required to explore the mechanisms underlying the association between lean NAFLD and specific GI cancers.

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.

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.

Higher mortality among lean patients with non-alcoholic fatty liver disease despite fewer metabolic comorbidities

BACKGROUND & AIMS

Non-alcoholic fatty liver disease (NAFLD) can develop in individuals who are not overweight. Whether lean persons with NAFLD have lower mortality and lower incidence of cirrhosis, cardiovascular diseases (CVD), diabetes mellitus (DM) and cancer than overweight/obese persons with NAFLD remains inconclusive. We compared mortality and incidence of cirrhosis, CVD, DM and cancer between lean versus non-lean persons with NAFLD.

METHODS

This is a retrospective study of adults with NAFLD in a single centre from 2012 to 2021. Primary outcomes were mortality and new diagnosis of cirrhosis, CVD, DM and cancer. Outcomes were modelled using competing risk analysis and Cox proportional hazards regression analysis.

RESULTS

A total of 18,594 and 13,420 patients were identified for cross-sectional and longitudinal analysis respectively: approximately 11% lean, 25% overweight, 28% class 1 obesity and 35% class 2-3 obesity. The median age was 51.0 years, 54.6% were women. The median follow-up was 49.3 months. Lean patients had lower prevalence of metabolic diseases at baseline and lower incidence of cirrhosis and DM than non-lean patients and no difference in CVD, any cancer or obesity-related cancer during follow-up. However, lean patients had significantly higher mortality with incidence per 1000 person-years of 16.67, 10.11, 7.37 and 8.99, respectively, in lean, overweight, obesity class 1 and obesity class 2-3 groups respectively.

CONCLUSIONS

Lean patients with NAFLD had higher mortality despite lower incidence of cirrhosis and DM, and similar incidence of CVD and cancer and merit similar if not more attention as non-lean patients with NAFLD.

Editorial: clinical outcomes in lean NAFLD - the devil is in the details. Authors' reply

This article is linked to Wijarnpreecha et al papers. To view these articles, visit https://doi.org/10.1111/apt.17424 and https://doi.org/10.1111/apt.17449

Immunometabolic factors contributing to obesity-linked hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a major public health concern that is promoted by obesity and associated liver complications. Onset and progression of HCC in obesity is a multifactorial process involving complex interactions between the metabolic and immune system, in which chronic liver damage resulting from metabolic and inflammatory insults trigger carcinogenesis-promoting gene mutations and tumor metabolism. Moreover, cell growth and proliferation of the cancerous cell, after initiation, requires interactions between various immunological and metabolic pathways that provide stress defense of the cancer cell as well as strategic cell death escape mechanisms. The heterogenic nature of HCC in addition to the various metabolic risk factors underlying HCC development have led researchers to focus on examining metabolic pathways that may contribute to HCC development. In obesity-linked HCC, oncogene-induced modifications and metabolic pathways have been identified to support anabolic demands of the growing HCC cells and combat the concomitant cell stress, coinciding with altered utilization of signaling pathways and metabolic fuels involved in glucose metabolism, macromolecule synthesis, stress defense, and redox homeostasis. In this review, we discuss metabolic insults that can underlie the transition from steatosis to steatohepatitis and from steatohepatitis to HCC as well as aberrantly regulated immunometabolic pathways that enable cancer cells to survive and proliferate in the tumor microenvironment. We also discuss therapeutic modalities targeted at HCC prevention and regression. A full understanding of HCC-associated immunometabolic changes in obesity may contribute to clinical treatments that effectively target cancer metabolism.

Effects of lifestyle intervention on adults with metabolic associated fatty liver disease: A systematic review and meta-analysis

INTRODUCTION

This systematic review and meta-analysis evaluates the overall effects of lifestyle interventions upon hepatic fat content and metabolism-related indicators among adults with metabolic associated fatty liver disease.

METHODS

It was registered under PROSPERO (CRD42021251527). We searched PubMed, EMBASE, MEDLINE, Cochrane, CINAHL, Scopus, CNKI, Wan-fang, VIP, and CBM from the inception of each database to May 2021 for RCT studies of lifestyle interventions on hepatic fat content and metabolism-related indicators. We used Review Manager 5.3 for meta-analysis and used text and detailed tabular summaries when heterogeneity existed.

RESULTS

Thirty-four RCT studies with 2652 participants were included. All participants were obesity, 8% of whom also had diabetes, and none was lean or normal weight. Through subgroup analysis, we found low carbohydrate diet, aerobic training and resistance training significantly improved the level of HFC, TG, HDL, HbA1c, and HOMA-IR. Moreover, low carbohydrate diet is more effective in improving HFC than low fat diet and resistance training is better than aerobic training in reduction in HFC and TG (SMD, -0.25, 95% CI, -0.45 to -0.06; SMD, 0.24, 95% CI, 0.03 to 0.44, respectively).

DISCUSSION

Overall, this is the first review that systematically synthesizes studies focused on the effects of various lifestyle on adults with MAFLD. The data generated in this systematic review were more applicable to obesity MAFLD rather than lean or normal weight MAFLD.

SYSTEMATIC REVIEW REGISTRATION

https://www.crd.york.ac.uk/prospero/, identifier (CRD42021251527).