Role of intensive dietary and lifestyle interventions in the treatment of lean nonalcoholic fatty liver disease patients

The effect of ertugliflozin in patients with nonalcoholic fatty liver disease associated with type 2 diabetes mellitus: A randomized controlled trial

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) is a chronic liver disease associated with liver inflammation, fibrosis, and cirrhosis and is associated with a greater risk of hepatocarcinoma. Nonalcoholic steatohepatitis (NASH) is a persistent and progressive form of NAFLD. Recent evidence suggested that ertugliflozin, a sodium-glucose cotransporter 2 inhibitor (SGLT2), suppresses NAFLD development in patients with type 2 diabetes mellitus (T2DM). The objective of this study was to determine the impact of ertugliflozin on improving NAFLD in patients with T2DM and the function of liver enzymes.

METHODS

This prospective, randomized, double-blind, placebo-controlled, interventional study aimed to determine the effectiveness of 15 mg of ertugliflozin versus 30 mg of the standard therapy pioglitazone versus placebo in NAFLD patients with T2DM. The study was established based on patient randomization in three groups: ertugliflozin, pioglitazone, and a placebo. This study was registered under the Australian New Zealand Clinical Trial Registry (Trial ID: ACTRN12624000032550).

RESULTS

The impact of therapy was determined in the treatment groups by utilizing liver ultrasonography and biochemical parameters. After 24 weeks of clinical study, the results revealed significant improvement in the grades of fatty liver, especially in the ertugliflozin group. The number of patients with hepatic steatosis significantly decreased among the respective groups classified according to fatty liver grade. Among patients in the ertugliflozin and pioglitazone groups, 45% to 23.4% and 41.7% to 26.6%, respectively, decreased in the Grade 2 group. The aspartate aminotransferase and alanine aminotransferase levels were significantly lower in all the study groups, especially in the ertugliflozin group (P ≤ .001).

CONCLUSION

The present study revealed that the concomitant use of ertugliflozin has favorable effects on liver enzymes, as it decreases liver fat intake and reduces complications in patients with NAFLD-associated T2DM. However, more in-depth studies will be required to observe every aspect of ertugliflozin.

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.

Association of variabilities in body mass index and waist circumference with newly achieved remission of metabolic dysfunction-associated fatty liver disease

AIMS

Although body weight reduction is recommended to ameliorate nonalcoholic fatty liver disease, the effects of body mass index (BMI) and waist circumference (WC) variability on newly achieved remission of metabolic dysfunction-associated fatty liver disease (MAFLD) remain unclear. We aimed to investigate the longitudinal association between BMI and WC variabilities and newly achieved MAFLD remission in both sexes.

METHODS

Among 26,952 patients, 1823 with MAFLD diagnosed by ultrasonography and with >2 health checkups over >2 years from April 2014 to March 2021 were included in this observational cohort study. A generalized estimation equation model analyzed the association between BMI and WC and newly achieved MAFLD remission according to repeated measures at baseline and the most recent stage.

RESULTS

Rates of MAFLD remission in male and female patients were 7.4 % and 6.0 %, respectively. Regarding decreased BMI variability, newly achieved MAFLD remission prevalence among the subgroups differed significantly between sexes (p < 0.001). In male patients, a decrease in BMI variability of ≥1.5 kg/m2 and WC variability of ≥4.2 cm had adjusted odds ratios (ORs) of 5.215 and 2.820, respectively, for newly achieved MAFLD remission. Among female patients, regular exercise and breakfast consumption were accelerating factors for newly achieved MAFLD remission. Non-invasive liver fibrosis scores significantly differed between MAFLD and newly achieved MAFLD remission, including in the subgroups (p < 0.01 and p < 0.001, respectively).

CONCLUSIONS

Reducing BMI and WC variabilities in male patients and improving lifestyle habits in female patients may accelerate MAFLD remission.

Metabolic dysfunction-associated steatotic liver disease: A silent pandemic

The worldwide epidemiology of non-alcoholic fatty liver disease (NAFLD) is showing an upward trend, parallel to the rising trend of metabolic syndrome, owing to lifestyle changes. The pathogenesis of NAFLD has not been fully understood yet. Therefore, NAFLD has emerged as a public health concern in the field of hepatology and metabolisms worldwide. Recent changes in the nomenclature from NAFLD to metabolic dysfunction-associated steatotic liver disease have brought a positive outlook changes in the understanding of the disease process and doctor-patient communication. Lifestyle changes are the main treatment modality. Recently, clinical trial using drugs that target 'insulin resistance' which is the driving force behind NAFLD, have shown promising results. Further translational research is needed to better understand the underlying pathophysiological mechanism of NAFLD which may open newer avenues of therapeutic targets. The role of gut dysbiosis in etiopathogenesis and use of fecal microbiota modification in the treatment should be studied extensively. Prevention of this silent epidemic by spreading awareness and early intervention should be our priority.

Nonalcoholic steatohepatitis: A comprehensive updated review of risk factors, symptoms, and treatment

Non-alcoholic steatohepatitis (NASH) is a subtype of nonalcoholic fatty liver disease and a progressive and chronic liver disorder with a significant risk for the development of liver-related morbidity and mortality. The complex and multifaceted pathophysiology of NASH makes its management challenging. Early identification of symptoms and management of patients through lifestyle modification is essential to prevent the development of advanced liver disease. Despite the increasing prevalence of NASH, there is no FDA-approved treatment for this disease. Currently, medications targeting metabolic disease risk factors and some antifibrotic medications are used for NASH patients but are not sufficiently effective. The beneficial effects of different drugs and phytochemicals represent new avenues for the development of safer and more effective treatments for NASH. In this review, different risk factors, clinical symptoms, diagnostic methods of NASH, and current treatment strategies for the management of patients with NASH are reviewed.

Update in lean metabolic dysfunction-associated steatotic liver disease

BACKGROUND

A new nomenclature consensus has emerged for liver diseases that were previously known as non-alcoholic fatty liver disease (NAFLD) and metabolic dysfunction-associated fatty liver disease (MAFLD). They are now defined as metabolic dysfunction-associated steatotic liver disease (MASLD), which includes cardiometabolic criteria in adults. This condition, extensively studied in obese or overweight patients, constitutes around 30% of the population, with a steady increase worldwide. Lean patients account for approximately 10%-15% of the MASLD population. However, the pathogenesis is complex and is not well understood.

AIM

To systematically review the literature on the diagnosis, pathogenesis, characteristics, and prognosis in lean MASLD patients and provide an interpretation of these new criteria.

METHODS

We conducted a comprehensive database search on PubMed and Google Scholar between January 2012 and September 2023, specifically focusing on lean NAFLD, MAFLD, or MASLD patients. We include original articles with patients aged 18 years or older, with a lean body mass index categorized according to the World Health Organization criteria, using a cutoff of 25 kg/m2 for the general population and 23 kg/m2 for the Asian population.

RESULTS

We include 85 studies in our analysis. Our findings revealed that, for lean NAFLD patients, the prevalence rate varied widely, ranging from 3.8% to 34.1%. The precise pathogenesis mechanism remained elusive, with associations found in genetic variants, epigenetic modifications, and adaptative metabolic response. Common risk factors included metabolic syndrome, hypertension, and type 2 diabetes mellitus, but their prevalence varied based on the comparison group involving lean patients. Regarding non-invasive tools, Fibrosis-4 index outperformed the NAFLD fibrosis score in lean patients. Lifestyle modifications aided in reducing hepatic steatosis and improving cardiometabolic profiles, with some medications showing efficacy to a lesser extent. However, lean NAFLD patients exhibited a worse prognosis compared to the obese or overweight counterpart.

CONCLUSION

MASLD is a complex disease comprising epigenetic, genetic, and metabolic factors in its pathogenesis. Results vary across populations, gender, and age. Limited data exists on clinical practice guidelines for lean patients. Future studies employing this new nomenclature can contribute to standardizing and generalizing results among lean patients with steatotic liver disease.

Prevalence and Risk Factors of Non-Alcoholic Fatty Liver Disease (NAFLD) in Non-Obese Patients with Schizophrenia: A Retrospective Study

Background

To assess the prevalence and risk factors of NAFLD in non-obese patients with schizophrenia in a public psychiatric hospital in China.

Methods

A total of 1,305 adult inpatients with schizophrenia in 2019 were included in this retrospective study. Body mass index (BMI) ≥ 25 kg/m2 was considered obese, and BMI < 25 kg/m2 was considered non-obese. We obtained the data from electronic records of the Affiliated Brain Hospital of Guangzhou Medical University.

Results

A total of 1,045 non-obese patients and 260 obese patients were included in this study. The prevalence of NAFLD in non-obese patients was 25.0%, and it was much lower that in the obese patients (25.0% vs 64.6%, p < 0.001). Among the non-obese patients, there were significant differences in age, BMI, alanine aminotransferase (ALT), metabolic indices, and the prevalence of diabetes and hypertension between patients with NAFLD and patients without NAFLD. According to the results of binary logistic regression analysis, age, BMI, ALT, triglyceride (TG) and diabetes were significantly related to NAFLD among non-obese patients with schizophrenia. In contrast, HDL-C was was negatively associated with NAFLD among non-obese patients.

Conclusion

This study suggested that NAFLD was common in patients with schizophrenia, even in non-obese patients with schizophrenia. In non-obese patients with schizophrenia, age, BMI, ALT, TG and diabetes are significantly associated with NAFLD. Moreover, HDL-C level was an independent protective factor against NAFLD. Given the adverse outcomes of NAFLD, it is necessary to increase awareness of NAFLD in patients with schizophrenia, especially in non-obese patients with schizophrenia.

Association between the traditional Chinese medicine constitution and metabolic dysfunction-associated fatty liver disease in older people: A cross-sectional study

Background

Few studies have focused on the relationship between the traditional Chinese medicine constitution (TCMC) and metabolic dysfunction-associated fatty liver disease (MAFLD) in older populations. We sought to investigate the distribution of MAFLD and the TCMC in older people, and provide a theoretical basis for TCMC-based management of MAFLD in this population.

Methods

A cross-sectional study was conducted among older (≥65 years) individuals in Zhongshan, China. Information on common sociodemographic characteristics, medical history, anthropometric measurements, and the TCMC was collected. The chi-square test, multivariable logistic regression analysis, subgroup analysis, and inverse probability weighting of the propensity score were used to explore the relationship between MAFLD and the TCMC.

Results

Of 7085 participants, 1408 (19.9 %) had MAFLD. The three most common TCMC types in MAFLD patients were "phlegm-dampness", "gentleness", and "yin-deficiency". After adjustment for gender, age, tobacco smoking, alcohol consumption, body mass index, abnormal waist-to-hip ratio, hypertension, diabetes mellitus, and dyslipidemia, MAFLD was positively associated with the phlegm-dampness constitution (PDC) (ORadjusted (95 % CI) = 1.776 (1.496-2.108), P < 0.001), and negatively correlated with the qi-depression constitution (0.643 (0.481-0.860), 0.003). A stronger correlation between the PDC and MAFLD was observed in men compared with women (ORadjusted = 2.04 (95%CI = 1.47-2.84) vs. 1.70 (95%CI = 1.39-2.08), Pinteraction = 0.003) as well as between people who smoked tobacco and non-tobacco-smoking individuals (2.11 (1.39-3.21) vs. 1.75 (1.45-2.12), 0.006).

Conclusions

A positive relationship was observed between MAFLD and the PDC in older people living in Zhongshan. Early detection and treatment of the PDC (especially in men and smokers) could prevent the occurrence and development of MAFLD.

The metabolic profiles and body composition of non-obese metabolic associated fatty liver disease

Background/purpose

Metabolic-associated fatty liver disease (MAFLD) is a major cause of chronic liver disease worldwide and is generally thought to be closely related to obesity and diabetes. However, it also affects non-obese individuals, particularly in Asian cultures.

Methods

Healthy physical examination subjects and MAFLD patients were included in the endocrinology department of Jiangsu Provincial Hospital of Traditional Chinese Medicine. MAFLD was defined as fatty liver in imaging without virus infection, drug, alcohol, or other known causes of chronic liver disease. Non-obese MAFLD was defined as MAFLD in non-obese subjects (BMI<25 kg/m2).

Results

The final analysis comprised 1047 participants in total. Of 946 MAFLD patients, 162 (17.12%) were diagnosed with non-obese MAFLD. Non-obese MAFLD patients were older, had lower alanine aminotransferase (ALT), triglyceride, and waist circumference, but had higher high density lipoprotein cholesterol (HDL-c) than obese MAFLD patients. Compared with non-obese healthy controls, non-obese MAFLD patients had higher BMI, ALT, gamma-glutamyl transferase (GGT), uric acid (UA), triglycerides (TG), and low density lipoprotein cholesterol (LDL-c). In terms of body composition, body fat mass (BFM), waist-hip ratio (WHR), percent body fat (PBF), visceral fat area (VFA), and fat mass index (FMI) were lower in non-obese healthy controls than non-obese MAFLD patients. A binary logistic regression analysis revealed that non-obese MAFLD was linked with lower GGT and higher HDL-c.

Conclusion

In this study cohort, non-obese MAFLD was present at a prevalence of 13.90%. In contrast to non-obese healthy controls, non-obese MAFLD patients exhibited different metabolic profiles, but they also had different body compositions.

TNFα is a key trigger of inflammation in diet-induced non-obese MASLD in mice

Tumor necrosis factor alpha (TNFα) is thought to be a critical factor in the development of metabolic dysfunction-associated steatotic liver disease (MASLD). Here, we determined the effects of a treatment with the anti-TNFα antibody infliximab and a genetic deletion of TNFα, respectively, in the development of non-obese diet-induced early metabolic dysfunction-associated steatohepatitis (MASH) in mice. The treatment with infliximab improved markers of liver damage in mice with pre-existing early MASH. In TNFα-/- mice, the development of early signs of MASH and insulin resistance was significantly attenuated compared to wild-type animals. While mRNA expression of proinflammatory cytokines like interleukin 1β (Il1b) and interleukin 6 (Il6) were significantly lower in livers of MASH-diet-fed TNFα-/- mice compared to wild-type mice with early MASH, markers of intestinal barrier function were similarly impaired in both MASH-diet-fed groups compared to controls. Our data suggest that TNFα is a key regulator of hepatic inflammation and insulin resistance associated with the development of early non-obese MASH.

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.

The Role of Choline, Soy Isoflavones, and Probiotics as Adjuvant Treatments in the Prevention and Management of NAFLD in Postmenopausal Women

Nonalcoholic fatty liver disease (NAFLD) is a prevalent condition among postmenopausal women that can lead to severe liver dysfunction and increased mortality. In recent years, research has focused on identifying potential lifestyle dietary interventions that may prevent or treat NAFLD in this population. Due to the complex and multifactorial nature of NAFLD in postmenopausal women, the disease can present as different subtypes, with varying levels of clinical presentation and variable treatment responses. By recognizing the significant heterogeneity of NAFLD in postmenopausal women, it may be possible to identify specific subsets of individuals who may benefit from targeted nutritional interventions. The purpose of this review was to examine the current evidence supporting the role of three specific nutritional factors-choline, soy isoflavones, and probiotics-as potential nutritional adjuvants in the prevention and treatment of NAFLD in postmenopausal women. There is promising evidence supporting the potential benefits of these nutritional factors for NAFLD prevention and treatment, particularly in postmenopausal women, and further research is warranted to confirm their effectiveness in alleviating hepatic steatosis in this population.

Metabolic dysfunction and nonalcoholic fatty liver disease risk in individuals with a normal body mass index

PURPOSE OF REVIEW

Nonalcoholic fatty liver disease (NAFLD) is strongly associated with obesity, but is also common in individuals with a normal body mass index (BMI), who also experience the hepatic inflammation, fibrosis, and decompensated cirrhosis associated with NAFLD progression. The clinical evaluation and treatment of NAFLD in this patient population are challenging for the gastroenterologist. A better understanding of the epidemiology, natural history, and outcomes of NAFLD in individuals with normal BMI is emerging. This review examines the relationship between metabolic dysfunction and clinical characteristics associated with NAFLD in normal-weight individuals.

RECENT FINDINGS

Despite a more favorable metabolic profile, normal-weight NAFLD patients exhibit metabolic dysfunction. Visceral adiposity may be a critical risk factor for NAFLD in normal-weight individuals, and waist circumference may be better than BMI for assessing metabolic risk in these patients. Although screening for NAFLD is not presently recommended, recent guidelines may assist clinicians in the diagnosis, staging, and management of NAFLD in individuals with a normal BMI.

SUMMARY

Individuals with a normal BMI likely develop NAFLD as a result of different etiologies. Subclinical metabolic dysfunction may be a key component of NAFLD in these patients, and efforts to better understand this relationship in this patient population are needed.

Nonalcoholic Fatty Liver Disease in Lean/Nonobese and Obese Individuals: A Comprehensive Review on Prevalence, Pathogenesis, Clinical Outcomes, and Treatment

Nonalcoholic fatty liver disease (NAFLD) is the most common liver disease worldwide, with an estimated prevalence of 25% globally. NAFLD is closely associated with metabolic syndrome, which are both becoming increasingly more common with increasing rates of insulin resistance, dyslipidemia, and hypertension. Although NAFLD is strongly associated with obesity, lean or nonobese NAFLD is a relatively new phenotype and occurs in patients without increased waist circumference and with or without visceral fat. Currently, there is limited literature comparing and illustrating the differences between lean/nonobese and obese NAFLD patients with regard to risk factors, pathophysiology, and clinical outcomes. In this review, we aim to define and further delineate different phenotypes of NAFLD and present a comprehensive review on the prevalence, incidence, risk factors, genetic predisposition, and pathophysiology. Furthermore, we discuss and compare the clinical outcomes, such as insulin resistance, dyslipidemia, hypertension, coronary artery disease, mortality, and progression to nonalcoholic steatohepatitis, among lean/nonobese and obese NAFLD patients. Finally, we summarize the most up to date current management of NAFLD, including lifestyle interventions, pharmacologic therapies, and surgical options.

Comparison between metabolic-associated fatty liver disease and nonalcoholic fatty liver disease: From nomenclature to clinical outcomes

As a result of the obesity epidemic, Nonalcoholic fatty liver disease (NAFLD) and its complications have increased among millions of people. Consequently, a group of experts recommended changing the term NAFLD to an inclusive terminology more reflective of the underlying pathogenesis; metabolic-associated fatty liver disease (MAFLD). This new term of MAFLD has its own disease epidemiology and clinical outcomes prompting efforts in studying its differences from NAFLD. This article discusses the rationale behind the nomenclature change, the main differences, and its clinical implications.

Metabolic (dysfunction)-associated fatty liver disease in individuals of normal weight

Metabolic (dysfunction)-associated fatty liver disease (MAFLD) affects up to a third of the global population; its burden has grown in parallel with rising rates of type 2 diabetes mellitus and obesity. MAFLD increases the risk of end-stage liver disease, hepatocellular carcinoma, death and liver transplantation and has extrahepatic consequences, including cardiometabolic disease and cancers. Although typically associated with obesity, there is accumulating evidence that not all people with overweight or obesity develop fatty liver disease. On the other hand, a considerable proportion of patients with MAFLD are of normal weight, indicating the importance of metabolic health in the pathogenesis of the disease regardless of body mass index. The clinical profile, natural history and pathophysiology of patients with so-called lean MAFLD are not well characterized. In this Review, we provide epidemiological data on this group of patients and consider overall metabolic health and metabolic adaptation as a framework to best explain the pathogenesis of MAFLD and its heterogeneity in individuals of normal weight and in those who are above normal weight. This framework provides a conceptual schema for interrogating the MAFLD phenotype in individuals of normal weight that can translate to novel approaches for diagnosis and patient care.

Nonalcoholic Fatty Liver Disease: Current Global Burden

The map and global disease burden of chronic liver diseases are markedly changing, with nonalcoholic fatty liver disease (NAFLD) becoming the most common cause of liver diseases coinciding with the current epidemics of obesity, type 2 diabetes, and metabolic syndrome. Understanding the incidence and prevalence of NAFLD is critical because of its linkage to a significant economic burden of hospitalization and changing patterns in consequences, such as liver transplantation. Moreover, the long-term average health care expenses of NAFLD patients have exceeded those of other liver diseases. To lessen the imminent burden of NAFLD, immediate actions to raise worldwide awareness and address metabolic risk factors are required. This review summarizes key data about the global disease burden of NAFLD, modifiable and nonmodifiable risk factors, and current preventive approaches.

Comparative Burden of Metabolic Dysfunction in Lean NAFLD vs Non-lean NAFLD - A Systematic Review and Meta-analysis

BACKGROUND & AIMS

Nonalcoholic fatty liver disease (NAFLD) is traditionally associated with obesity. However, there is a subtype of NAFLD, namely NAFLD in lean, that occurs without obesity. However, a recent call to redefine NAFLD to metabolic-associated fatty liver disease focuses on obesity and metabolic dysfunction. Criticism has arisen from the perceived over emphasis on systemic comorbidities, which may disadvantage the lean. The current analysis seeks to quantify the degree of metabolic dysfunction in NAFLD in lean and compare with NAFLD in overweight and obese and non-NAFLD.

METHODS

Medline and Embase databases were searched from inception to March 3, 2022. The inclusion criteria were articles with NAFLD in lean patients presenting with baseline metabolic parameters. Comparisons were conducted with subgroup analysis.

RESULTS

Eighty-five articles were included in the meta-analysis. NAFLD in lean accounted for 13.11% (95% confidence interval [CI], 10.26%-16.62%) of the global population and 14.55% (95% CI, 11.32%-18.51%) in Asia. The degree of metabolic dysfunction was weight dependent with significantly less metabolic dysfunction in NAFLD in lean subjects as compared with NAFLD in overweight counterparts. For NAFLD in lean, only 19.56% (95% CI, 15.28%-24.69%) of the subjects were diabetic, whereas 45.70% (95% CI, 35.01%-56.80%) of obese subjects with NAFLD had diabetes (P < .01). Fasting blood glucose and systolic and diastolic blood pressure values were significantly lower in subjects with NAFLD in lean than in overweight and obese.

CONCLUSION

The current analysis highlights the weight-dependent nature of metabolic dysfunction in NAFLD. Lean subjects with NAFLD were significantly less metabolically unhealthy than were obese and overweight persons with NAFLD. An overreliance on metabolic dysfunction in defining fatty liver will be a flaw in potentially excluding previously characterized NAFLD.

Metabolic-associated Fatty Liver Disease (MAFLD): A Multi-systemic Disease Beyond the Liver

Nonalcoholic fatty liver disease (NAFLD) is a multisystemic clinical condition that presents with a wide spectrum of extrahepatic manifestations, such as obesity, type 2 diabetes mellitus, metabolic syndrome, cardiovascular diseases, chronic kidney disease, extrahepatic malignancies, cognitive disorders, and polycystic ovarian syndrome. Among NAFLD patients, the most common mortality etiology is cardiovascular disorders, followed by extrahepatic malignancies, diabetes mellitus, and liver-related complications. Furthermore, the severity of extrahepatic diseases is parallel to the severity of NAFLD. In clinical practice, awareness of the associations of concomitant diseases is of major importance for initiating prompt and timely screening and multidisciplinary management of the disease spectrum. In 2020, a consensus from 22 countries redefined the disease as metabolic (dysfunction)-associated fatty liver disease (MAFLD), which resulted in the redefinition of the corresponding population. Although the patients diagnosed with MAFLD and NAFLD mostly overlap, the MAFLD and NAFLD populations are not identical. In this review, we compared the associations of key extrahepatic diseases between NAFLD and MAFLD.

MAFLD enhances clinical practice for liver disease in the Asia-Pacific region

Fatty liver is now a major cause of liver disease in the Asia-Pacific region. Liver diseases in this region have distinctive characteristics. First, fatty liver is frequently observed in lean/normal-weight individuals. However, there is no standard definition of this unique phenotype. Second, fatty liver is often observed in patients with concomitant viral hepatitis. The exclusion of viral hepatitis from non-alcoholic fatty liver disease limits its value and detracts from the investigation and holistic management of coexisting fatty liver in patients with viral hepatitis. Third, fatty liver-associated hepatocellular carcinoma (HCC) is generally categorized as non-B non-C HCC. Fourth, the population is aging rapidly, and it is imperative to develop a practicable, low-intensity exercise program for elderly patients. Fifth, most patients and nonspecialized healthcare professionals still lack an awareness of the significance of fatty liver both in terms of intrahepatic and extrahepatic disease and cancer. Recently, an international expert panel proposed a new definition of fatty liver: metabolic dysfunction-associated fatty liver disease (MAFLD). One feature of MAFLD is that metabolic dysfunction is a prerequisite for diagnosis. Pertinent to regional issues, MAFLD also provides its diagnostic criteria in lean/normal-weight individuals. Furthermore, MAFLD is independent of any concomitant liver disease, including viral hepatitis. Therefore, MAFLD may be a more suitable definition for fatty liver in the Asia-Pacific region. In this review, we introduce the regional characteristics of fatty liver and discuss the advantages of MAFLD for improving clinical practice for liver disease in the region.

NAFLD in normal weight individuals

Nonalcoholic fatty liver disease (NAFLD) can develop in lean individuals. Despite a better metabolic profile, the risk of disease progression to hepatic inflammation, fibrosis, and decompensated cirrhosis in the lean is similar to that in obesity-related NAFLD and lean individuals may experience more severe hepatic consequences and higher mortality relative to those with a higher body mass index (BMI). In the absence of early symptoms and abnormal laboratory findings, lean individuals are not likely to be screened for NAFLD or related comorbidities; however, given the progressive nature of the disease and the increased risk of morbidity and mortality, a clearer understanding of the natural history of NAFLD in lean individuals, as well as efforts to raise awareness of the potential health risks of NAFLD in lean individuals, are warranted. In this review, we summarize available data on NAFLD prevalence, clinical characteristics, outcomes, and mortality in lean individuals and discuss factors that may contribute to the development of NAFLD in this population, including links between dietary and genetic factors, menopausal status, and ethnicity. We also highlight the need for greater representation of lean individuals in NAFLD-related clinical trials, as well as more studies to better characterize lean NAFLD, develop improved screening algorithms, and determine specific treatment strategies based on underlying etiology.

Accuracy of Fibrosis-4 index and non-alcoholic fatty liver disease fibrosis scores in metabolic (dysfunction) associated fatty liver disease according to body mass index: failure in the prediction of advanced fibrosis in lean and morbidly obese individuals

BACKGROUND AND AIM

While non-invasive scores are increasingly being used to screen for advanced fibrosis in metabolic (dysfunction) associated fatty liver disease (MAFLD), the effect of BMI on their clinical utility remains uncertain. This study assessed the usefulness of the Fibrosis-4 index (FIB-4) and the non-alcoholic fatty liver disease fibrosis score (NFS) in lean, overweight, obese, severely obese, and morbidly obese patients with biopsy-proven MAFLD.

METHODS

A total of 560 patients (28 lean, 174 overweight, 229 obese, 89 severely obese, 40 morbidly obese) were included. Diagnostic performances and optimal cut-off values for FIB-4 and NFS were calculated using receiver operating characteristic (ROC) curve analysis.

RESULTS

In both lean and morbidly obese patients with MAFLD, both FIB-4 and NFS failed to discriminate advanced fibrosis. Conversely, both scores showed acceptable diagnostic performances in exclusion of advanced fibrosis in overweight, obese, and severely obese patients. FIB-4 was able to exclude advanced fibrosis with the highest diagnostic accuracy in the subgroup of overweight patients (area under the ROC curve: 0.829, 95% confidence interval: 0.738-0.919).

CONCLUSION

FIB-4 and NFS can confidently be used to exclude advanced fibrosis in overweight, obese, and severely obese patients. However, they do not appear clinically useful in lean and morbidly obese patients.

Understanding the Role of the Gut Microbiome and Microbial Metabolites in Non-Alcoholic Fatty Liver Disease: Current Evidence and Perspectives

Non-alcoholic fatty liver disease (NAFLD) is the most common chronic liver disease worldwide. NAFLD begins as a relatively benign hepatic steatosis which can evolve to non-alcoholic steatohepatitis (NASH); the risk of cirrhosis and hepatocellular carcinoma (HCC) increases when fibrosis is present. NAFLD represents a complex process implicating numerous factors—genetic, metabolic, and dietary—intertwined in a multi-hit etiopathogenetic model. Recent data have highlighted the role of gut dysbiosis, which may render the bowel more permeable, leading to increased free fatty acid absorption, bacterial migration, and a parallel release of toxic bacterial products, lipopolysaccharide (LPS), and proinflammatory cytokines that initiate and sustain inflammation. Although gut dysbiosis is present in each disease stage, there is currently no single microbial signature to distinguish or predict which patients will evolve from NAFLD to NASH and HCC. Using 16S rRNA sequencing, the majority of patients with NAFLD/NASH exhibit increased numbers of Bacteroidetes and differences in the presence of Firmicutes, resulting in a decreased F/B ratio in most studies. They also present an increased proportion of species belonging to Clostridium, Anaerobacter, Streptococcus, Escherichia, and Lactobacillus, whereas Oscillibacter, Flavonifaractor, Odoribacter, and Alistipes spp. are less prominent. In comparison to healthy controls, patients with NASH show a higher abundance of Proteobacteria, Enterobacteriaceae, and Escherichia spp., while Faecalibacterium prausnitzii and Akkermansia muciniphila are diminished. Children with NAFLD/NASH have a decreased proportion of Oscillospira spp. accompanied by an elevated proportion of Dorea, Blautia, Prevotella copri, and Ruminococcus spp. Gut microbiota composition may vary between population groups and different stages of NAFLD, making any conclusive or causative claims about gut microbiota profiles in NAFLD patients challenging. Moreover, various metabolites may be involved in the pathogenesis of NAFLD, such as short-chain fatty acids, lipopolysaccharide, bile acids, choline and trimethylamine-N-oxide, and ammonia. In this review, we summarize the role of the gut microbiome and metabolites in NAFLD pathogenesis, and we discuss potential preventive and therapeutic interventions related to the gut microbiome, such as the administration of probiotics, prebiotics, synbiotics, antibiotics, and bacteriophages, as well as the contribution of bariatric surgery and fecal microbiota transplantation in the therapeutic armamentarium against NAFLD. Larger and longer-term prospective studies, including well-defined cohorts as well as a multi-omics approach, are required to better identify the associations between the gut microbiome, microbial metabolites, and NAFLD occurrence and progression.

Macro- and micronutrients in metabolic (dysfunction) associated fatty liver disease: association between advanced fibrosis and high dietary intake of cholesterol/saturated fatty acids

BACKGROUND AND AIM

There is still no approved pharmacotherapy for metabolic (dysfunction) associated fatty liver disease (MAFLD). Although dietary and lifestyle modifications for weight loss remain the mainstay for disease management, the association between macro- and micronutrients and fibrosis stage in patients with MAFLD remains unclear. This study was undertaken to address this issue.

METHODS

This is a retrospective analysis of prospectively collected data from patients in whom MAFLD was diagnosed with vibration controlled transient elastography. Steatosis was defined by a controlled attenuation parameter ≥238 dB/m, whereas a liver stiffness measurement ≥11 kPa was considered to indicate advanced fibrosis.

RESULTS

The study sample consisted of 106 patients with MAFLD (mean age 49 ± 10 years, 52 men and 54 women). Among the different micro- and macronutrients tested, only the dietary intake of cholesterol and saturated fatty acid (SFA) was independently associated with the presence of advanced fibrosis.

CONCLUSION

Our findings suggest that cholesterol/SFA-restricted dietary regimens - as exemplified by the traditional Mediterranean diet - may reduce the risk of advanced fibrosis in patients with MAFLD.

The effect of anthocyanins supplementation on liver enzymes among patients with metabolic disorders: A systematic review and meta-analysis of randomized clinical trials

The present study aims to summarize and quantitatively examine the available evidence on the effectiveness of anthocyanin supplementation on liver enzymes among patients with metabolic disorders, by employing a systematic review and meta-analytic approach. Online databases including PubMed/Medline, Scopus, ISI Web of Science, and Cochrane Library were searched up to June 2020 for randomized controlled trials (RCTs) that examined the effect of anthocyanin supplementation on serum levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) among patients with metabolic disorders. To estimate the overall effect of anthocyanin supplementation, we employed the random-effects model. In total, 12 RCTs were included in the systematic review. Pooled analysis did not show any significant changes in ALT (WMD: -0.92 U/L, 95% CI: -4.19 to 2.35, p = .58; I²  = 91.3%) and AST (WMD: -1.22 U/L, 95% CI: -3.43 to 0.99, p = .28; I²  = 87.0) concentrations after supplementation with anthocyanin. The dose and duration of supplementation were the potential sources of heterogeneity among most of the trials. However, subgroup analysis showed that the effect is not statistically significant in all subgroups. Overall, in our study, anthocyanin does not have any effect on liver enzyme levels significantly. However, future high-quality studies are still needed to confirm the results.

Lean NAFLD: an underrecognized and challenging disorder in medicine

Classically, Non-Alcoholic Fatty Liver Disease (NAFLD) has been thought to be driven by excessive weight gain and obesity. The overall greater awareness of this disorder has led to its recognition in patients with normal body mass index (BMI). Ongoing research has helped to better understand potential causes of Lean NAFLD, the risks for more advanced disease, and potential therapies. Here we review the recent literature on prevalence, risk factors, severity of disease, and potential therapeutic interventions.

Body weight variability and the risk of cardiovascular outcomes in patients with nonalcoholic fatty liver disease

We investigated the association between body weight variability and the risks of cardiovascular disease and mortality in patients with nonalcoholic fatty liver disease (NAFLD) using large-scale, nationwide cohort data. We included 726,736 individuals with NAFLD who underwent a health examination between 2009 and 2010. NAFLD was defined as a fatty liver index ≥ 60, after excluding significant alcohol intake, viral hepatitis, and liver cirrhosis. Body weight variability was assessed using four indices, including variability independent of the mean (VIM). During a median 8.1-year follow-up, we documented 11,358, 14,714, and 22,164 cases of myocardial infarction (MI), stroke, and all-cause mortality, respectively. Body weight variability was associated with an increased risk of MI, stroke, and mortality after adjusting for confounding variables. The hazard ratios (HRs) (95% confidence intervals) for the highest quartile, compared with the lowest quartile, of VIM for body weight were 1.15 (1.10-1.20), 1.22 (1.18-1.26), and 1.56 (1.53-1.62) for MI, stroke, and all-cause mortality, respectively. Body weight variability was associated with increased risks of MI, stroke, and all-cause mortality in NAFLD patients. Appropriate interventions to maintain a stable weight could positively affect health outcomes in NAFLD patients.

Dietary Interventions in Liver Diseases: Focus on MAFLD and Cirrhosis

Purpose of Review

Dietary interventions (DI) aimed at improving overweight and metabolic abnormalities in metabolic dysfunction-associated fatty liver disease (MAFLD) and at reducing malnutrition and sarcopenia in cirrhosis should become part of routine care in hepatology. This review focuses on recent advances in this field.

Recent Findings

In patients with MAFLD, a gradual reduction, respectively, of 7–10% of body weight if overweight or of 3–5% if lean, obtained by moderately reducing caloric intake, is effective to improve liver disease. Intermittent energy restriction might be an alternative to continuous energy restriction with higher adherence. Qualitative dietary adjustments should include increased intake of unprocessed foods including fruits and vegetables, whole grains, fiber, and unsaturated fatty acids (FAs), for example, through a Mediterranean diet. Refined carbohydrates (CHOs), saturated FA (SFAs), red meat, and processed meat should be limited. DI studies in HIV-infected subjects with MAFLD are very limited, and this is a field for future research. In patients with cirrhosis, DI should aim at correcting malnutrition and improving skeletal muscle mass. Daily diet contents should aim at achieving 30–35 kcal/kg of body weight, including 1.2–1.5 g/kg proteins, and oral or enteral supplementation might be used in patients unable to achieve these targets. In some studies, branched-chain amino acids (BCAAs) proved to be effective in improving muscle mass and were associated with a lower risk of hepatic encephalopathy. Obesity requires adjustment of the above-mentioned targets, and its management is challenging. Studies looking at the efficacy of DI recommended by the existing guidelines on clinical endpoints are a field for future research.

Summary

Dietary interventions are able to improve MAFLD and show potential to reduce complications in liver disease. Despite its key importance, there are many barriers limiting the implementation of DI in patients with chronic liver disease. Patients’ empowerment is crucial and should be the focus of specific educational programs. In addition, liver clinics would benefit from multidisciplinary teams involving experts in nutrition, physical exercise, primary care physicians, and psychologists when needed.

Calcium to magnesium intake ratio and non-alcoholic fatty liver disease development: a case-control study

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is the most common chronic liver disease worldwide. Adoption of sedentary life style and westernized diet are shown to be associated with development of NAFLD. Since previous studies suggested that calcium (Ca) to magnesium (Mg) ratio intake is associated with some chronic diseases including dyslipidemia and insulin resistance, we designed this study to find any possible association between this ratio and NAFLD development.

METHODS

The NAFLD was diagnosed using Fibroscan according to a CAP cut-off value of 263 dB/m. Dietary intakes of one hundred and ninety-six patients with incident NAFLD diagnosis, and eight hundred and three controls without NAFLD were assessed using a valid food frequency questionnaire (FFQ). Dietary nutrients were calculated using Nutritionist IV software.

RESULTS

Age of the study population (57 % female) was 43.2 ± 14.1 years. In addition, energy-adjusted daily calcium to magnesium intake ratio was 2.34 ± 0.57 and 2.73 ± 0.69 for control and case groups, respectively. In the multivariable-adjusted model, after adjustment for potential confounding variables; including, age, gender, BMI, alcohol consumption, smoking, diabetes, physical activity, energy, dietary fiber, carbohydrate, fat, and protein intakes, participants in the third (Q3) and fourth (Q4) quartile of Ca/Mg ratio intake had a greater development of incidental NAFLD compared to the lowest quartile (Q1) [(OR = 2.86; 95 % CI: 1.20-6.81), (P-value = 0.017) and (OR = 5.97; 95 % CI: 2.54-14.01), (P-value < 0.001) for Q3 and Q4 compared to the Q1, respectively]. Moreover, energy-adjusted Ca to Mg intake ratio was positively correlated with plasma level of ALT (r = 0.18; P = 0.01); contrarily, it had no correlation with plasma levels of AST.

CONCLUSIONS

The current study revealed that higher dietary Ca to Mg intake ratio is associated with a greater development of NAFLD. Further interventional studies are needed to confirm the causal relationship of the Ca/Mg ratio intake and development of NAFLD.

Nutritional Approach Targeting Gut Microbiota in NAFLD-To Date

Non-alcoholic fatty liver disease (NAFLD) is a significant clinical and epidemiological problem that affects around 25% of the adult global population. A large body of clinical evidence highlights that NAFLD is associated with increased liver-related morbidity and mortality and an increased risk of cardiovascular disease, extrahepatic cancers, type 2 diabetes, and chronic kidney disease. Recently, a series of studies revealed the pivotal role of gut microbiota (GM) dysbiosis in NAFLD's pathogenesis. The GM plays an essential role in different metabolic pathways, including the fermentation of diet polysaccharides, energy harvest, choline regulation, and bile acid metabolism. One of the most critical factors in GM stabilization is the diet; therefore, nutritional therapyappearsto be a promising tool in NAFLD therapy. This paper aims to review the current knowledge regardingthe nutritional approach and its implications with GM and NAFLD treatment. We discuss the positive impact of probiotics, prebiotics, and symbiotics in a reverse dysbiosis state in NAFLD and show the potential beneficial effects of bioactive substances from the diet. The full description of the mechanism of action and comprehensive examination of the impact of nutritional interventions on GM modulation may, in the future, be a simple but essential tool supporting NAFLD therapy.

Epidemiology, Pathogenesis, Diagnosis and Emerging Treatment of Nonalcoholic Fatty Liver Disease

Nonalcoholic fatty liver disease (NAFLD) is the most common chronic liver disease, with an estimated rising prevalence, in concert with the epidemics of obesity and type 2 diabetes. The pathogenesis of NAFLD is not fully elucidated. Besides weight gain and insulin resistance, many other factors seem to contribute, including adipokines, gut microbiota and genetic predisposition. The disease starts as hepatic steatosis, which may proceed to nonalcoholic steatohepatitis (NASH); if fibrosis is added, the risk of cirrhosis and/or hepatocellular carcinoma is augmented. Liver biopsy is considered the gold standard for the diagnosis and staging of NAFLD; the early use of reliable and easily applied diagnostic tools, such as noninvasive biomarkers, is needed to identify patients at different-preferably early-stages of disease however. Whilst lifestyle modification is the first step to manage NAFLD, there is poor compliance, leading to the need of drug therapy. Accordingly, a variety of medications is under investigation. Given the multifaceted pathophysiology of NAFLD, probably, a combination of approaches in an individualized basis may be a more appropriate management. This review summarizes evidence on the epidemiology, pathogenesis, diagnosis and treatment of NAFLD.

The Asian Pacific Association for the Study of the Liver clinical practice guidelines for the diagnosis and management of metabolic associated fatty liver disease

Metabolic associated fatty liver disease (MAFLD) is the principal worldwide cause of liver disease and affects nearly a quarter of the global population. The objective of this work was to present the clinical practice guidelines of the Asian Pacific Association for the Study of the Liver (APASL) on MAFLD. The guidelines cover various aspects of MAFLD including its epidemiology, diagnosis, screening, assessment, and treatment. The document is intended for practical use and for setting the stage for advancing clinical practice, knowledge, and research of MAFLD in adults, with specific reference to special groups as necessary. The guidelines also seek to improve patient care and awareness of the disease and assist stakeholders in the decision-making process by providing evidence-based data. The guidelines take into consideration the burden of clinical management for the healthcare sector.

Direct access lifestyle training improves liver biochemistry and causes weight loss but uptake is suboptimal in patients with non-alcoholic fatty liver disease

OBJECTIVE

To evaluate the uptake and effectiveness of an existing open access lifestyle intervention forged in collaboration between a third sector organisation, funded by local government and a secondary care non-alcoholic fatty liver disease (NAFLD) service in the North West of England.

METHOD

A service outcome evaluation using precomparison design and postcomparison design was conducted to analyse changes between baseline clinical health records and 12-week follow-up for patients with NAFLD who completed the lifestyle intervention. Lifestyle factors, weight loss, changes in alanine aminotransferase (ALT) enzymes and lipid profiles were compared between patients who completed the programme vs 1:1 matched patients who did not.

RESULTS

Only 16 of 167 patients with NAFLD offered the intervention completed the programme. Intervention patients achieved significant weight loss (-2.3% p≤0.05) over 12 weeks, where the non-intervention group had non-significant weight gain (+0.95%). ALT improved by 20.6 IU/L in the interventional group and 15.75 IU/L in the non-intervention group; however, this was not statistically different.

CONCLUSION

This study presents first of its kind evaluation of a service collaboration in the UK. Only 1 in 10 patients offered the opportunity completed the programme, a limitation that could affect future strategies. Patient and public involvement research is needed to identify barriers to participation, address adherence issues and identify support mechanisms for lifestyle interventions in patients with NAFLD.

Nonalcoholic fatty liver disease in lean subjects: Prognosis, outcomes and management

Nonalcoholic fatty liver disease (NAFLD) accounts for most cases of chronic liver disease worldwide, with an estimated global prevalence of approximately 25% and ranges from simple steatosis to nonalcoholic steatohepatitis and cirrhosis. NAFLD is strongly connected to metabolic syndrome, and for many years, fatty liver was considered to be an exclusive feature of obese patients. However, recent studies have highlighted the presence of NAFLD in non-obese subjects, with or without increased visceral fat or even in lean subjects without increased waist circumference. "Lean NAFLD" is a relatively new concept and there is significant scientific interest in understanding the differences in pathophysiology, prognosis and management compared with NAFLD in overweight/obese patients. In the present editorial, we discuss the clinical and metabolic profiles and outcomes of lean NAFLD compared with both obese NAFLD and lean healthy individuals from Asian and Western countries. Moreover, we shed light to the challenging topic of management of NAFLD in lean subjects since there are no specific guidelines for this population. Finally, we discuss open questions and issues to be addressed in the future in order to categorize NAFLD patients into lean and non-lean cohorts.