More Evidence for the Genetic Susceptibility of Mexican Population to Nonalcoholic Fatty Liver Disease through PNPLA3

Sex and Race-Ethnic Disparities in Metabolic Dysfunction-Associated Steatotic Liver Disease: An Analysis of 40,166 Individuals

BACKGROUND

To overcome the limitations of the term "non-alcoholic fatty liver disease" (NAFLD), the term metabolic-associated steatotic liver disease (MASLD) was introduced. While epidemiologic studies have been conducted on MASLD, there is limited evidence on its associated sex and ethnic variations.

AIMS

This study assesses the differences across sex and race-ethnicity on the prevalence, associated risk factors and adverse outcomes in individuals with MASLD.

METHODS

Data retrieved from the National Health and Nutrition Examination Survey between 1999 to 2018 was analyzed. Prevalence, clinical characteristics, and outcomes were evaluated according to sex and race-ethnicity. Adverse outcomes and mortality events were analyzed using multivariate analyses.

RESULTS

Of 40,166 individuals included, 37.63% had MASLD. There was a significant increase in MASLD prevalence from 1999 to 2018 among Mexican Americans (Annual Percentage Change [APC] + 1.889%, p < 0.001), other Hispanics (APC + 1.661%, p = 0.013), NH Whites (APC + 1.084%, p = 0.018), NH Blacks (APC + 1.108%, p = 0.007), and females (APC + 0.879%, p = 0.030), but not males. Females with MASLD were at lower risk of all-cause (HR: 0.766, 95%CI 0.711 to 0.825, p < 0.001), cardiovascular disease-related (CVD) (SHR: 0.802, 95% CI 0.698 to 0.922, p = 0.002) and cancer-related mortality (SHR: 0.760, 95% CI 0.662 to 0.873, p < 0.001). Significantly, NH Blacks have the highest risk of all-cause and CVD-related mortality followed by NH Whites then Mexican Americans.

CONCLUSION

There has been an increase in prevalence in most race-ethnicities over time. While the change in definition shows no significant differences in previous associations found in NAFLD, the increased mortality in NH Whites relative to Mexican Americans remains to be explored.

Associations of five dietary indices with metabolic dysfunction-associated steatotic liver disease and liver fibrosis among the United States population

Background and aims

The role of dietary factors in metabolic dysfunction-associated steatotic liver disease (MASLD)-which represents a new definition of liver steatosis and metabolic dysfunction- remains unclear. This study aimed to explore the relationships between dietary indices and MASLD.

Methods

We analyzed data from the United States National Health and Nutrition Examination Survey (NHANES) 2017-2020 cycle, including 4,690 participants with complete vibration-controlled transient elastography (VCTE) data. Multivariate logistic regression models adjusted for covariates were used to assess the association between dietary indices, MASLD, and MASLD-associated liver fibrosis (MASLD-LF). Restricted cubic spline (RCS) models and subgroup analyses were also performed.

Results

The Alternative Healthy Eating Index (AHEI), Healthy Eating Index-2020 (HEI-2020), Dietary Approaches to Stop Hypertension Index (DASHI), and Mediterranean Diet Index (MEDI) were found to be negatively associated with MASLD risk, while the Dietary Inflammatory Index (DII) had a positive association. The highest quartile of MEDI was linked to a 44% reduction in MASLD risk [Q1 vs. Q4 odds ratio (OR): 0.56; 95% confidence interval (CI): 0.34-0.94, P for trend: 0.012]. DASHI was uniquely associated with a reduced risk of MASLD-LF (continuous OR: 0.79; 95% CI: 0.64-0.97; p for trend: 0.003). Our RCS curves indicated a nonlinear association with DASHI-MASLD (p-overall: 0.0001, p-nonlinear: 0.0066). Subgroup analyses showed robust associations among the non-Hispanic White and highly educated populations.

Conclusion

Specific dietary patterns were associated with reduced risks of MASLD and MASLD-LF. The DASHI, in particular, showed a significant protective effect against MASLD-LF. These findings suggest potential dietary interventions for managing MASLD and MASLD-LF, although large-scale randomized controlled trials are warranted to validate these findings.

Overall and subgroup prevalence of non-alcoholic fatty liver disease and prevalence of advanced fibrosis in the United States: An updated national estimate in National Health and Nutrition Examination Survey (NHANES) 2011-2018

INTRODUCTION AND OBJECTIVES

Data on the prevalence of non-alcoholic fatty liver disease (NAFLD) in subgroups of the United States (US) population are limited. This study was conducted to estimate NAFLD prevalence overall and by subgroups, and prevalence of NAFLD with advanced fibrosis.

MATERIALS AND METHODS

Using the National Health and Nutrition Examination Survey (NHANES) 2011-2018 data, a cross-sectional study was conducted. NAFLD was defined as having a US Fatty Liver Index (USFLI) ≥ 30 in the absence of other causes of liver disease, including excessive alcohol intake, chronic hepatitis B, and chronic hepatitis C. Likelihood for having advanced fibrosis was determined by the calculated NAFLD fibrosis score (NFS; high ≥ 0.676; low < -1.445) and fibrosis-4 index (FIB-4; high ≥ 2.67; low < 1.30).

RESULTS

The weighted national prevalence of NAFLD in US adults was 26.7% (95% confidence interval: 25.3%-28.1%). Prevalence was higher among those aged ≥ 65 years, males, Mexican Americans, with BMI ≥ 35 kg/m2 (class 2 and 3 obesity) and with type 2 diabetes (T2D). Of those meeting the USFLI criterion for NAFLD, 18.1% and 3.7% were determined as having a high probability of advanced fibrosis based on NFS ≥ 0.676 and FIB-4 ≥ 2.67 cut-off values, respectively.

CONCLUSIONS

This study supports an increased prevalence of NAFLD in specific subpopulations (aged ≥ 65 years, males, Mexican Americans, obese population, and patients with T2D). The observed difference in the prevalence of advanced fibrosis as estimated by NFS and FIB-4 highlights the challenge of choosing optimal cut-off values.

Personalized Risk Assessment of Hepatic Fibrosis after Cholecystectomy in Metabolic-Associated Steatotic Liver Disease: A Machine Learning Approach

Metabolic Associated Fatty Liver Disease (MASLD) is a condition that is often present in patients with a history of cholecystectomy. This is because both situations share interconnected metabolic pathways. This study aimed to establish a predictive model that allows for the identification of patients at risk of developing hepatic fibrosis following this surgery, with potential implications for surgical decision-making. A retrospective cross-sectional analysis was conducted in four hospitals using a database of 211 patients with MASLD who underwent cholecystectomy. MASLD diagnosis was established through liver biopsy or FibroScan, and non-invasive test scores were included for analysis. Various Machine Learning (ML) methods were employed, with the Adaptive Boosting (Adaboost) system selected to build the predictive model. Platelet level emerged as the most crucial variable in the predictive model, followed by dyslipidemia and type-2 diabetes mellitus. FIB-4 score proved to be the most reliable non-invasive test. The Adaboost algorithm improved the results compared to the other methods, excelling in both accuracy and area under the curve (AUC). Moreover, this system holds promise for implementation in hospitals as a valuable diagnostic support tool. In conclusion, platelet level (<150,000/dL), dyslipidemia, and type-2 diabetes mellitus were identified as primary risk factors for liver fibrosis in MASLD patients following cholecystectomy. FIB-4 score is recommended for decision-making, particularly when the indication for surgery is uncertain. This predictive model offers valuable insights into risk stratification and personalized patient management in post-cholecystectomy MASLD cases.

A Machine Learning-Based Method for Detecting Liver Fibrosis

Cholecystectomy and Metabolic-associated steatotic liver disease (MASLD) are prevalent conditions in gastroenterology, frequently co-occurring in clinical practice. Cholecystectomy has been shown to have metabolic consequences, sharing similar pathological mechanisms with MASLD. A database of MASLD patients who underwent cholecystectomy was analysed. This study aimed to develop a tool to identify the risk of liver fibrosis after cholecystectomy. For this purpose, the extreme gradient boosting (XGB) algorithm was used to construct an effective predictive model. The factors associated with a better predictive method were platelet level, followed by dyslipidaemia and type-2 diabetes (T2DM). Compared to other ML methods, our proposed method, XGB, achieved higher accuracy values. The XGB method had the highest balanced accuracy (93.16%). XGB outperformed KNN in accuracy (93.16% vs. 84.45%) and AUC (0.92 vs. 0.84). These results demonstrate that the proposed XGB method can be used as an automatic diagnostic aid for MASLD patients based on machine-learning techniques.

Trends in prevalence and all-cause mortality of metabolic dysfunction-associated fatty liver disease among adults in the past three decades: Results from the NHANES study

BACKGROUND

Given the escalating epidemic of obesity and diabetes coupled with redefined diagnostic criteria, it is critical to identify the prevalence of metabolic dysfunction-associated fatty liver disease (MAFLD). We sought to determine the prevalence and mortality outcomes of MAFLD subtypes based on diagnostic criteria in the USA over the past three decades.

METHODS

Eleven cycles of the National Health and Nutrition Examination Surveys (NHANES; 1988-1994 and 1999-2020) were used, and 72,224 participants were included. MAFLD was defined according to the 2020 International Expert Consensus. Based on diagnostic criteria and risk factors, MAFLD was categorized into seven subtypes: type 1 (obesity subtype), 2 (metabolic unhealthy subtype), 3 (diabetes subtype), 4 (metabolic unhealthy non-diabetes subtype), 5 (obesity and diabetes subtype), 6 (metabolic unhealthy non-obesity subtype), and 7 (mixed subtype).

RESULTS

Over the study period, the estimated prevalence of MAFLD increased significantly from 22% in 1988-1994 to 36% in 2017-2020. The prevalence of Type 4 was the highest, followed by that of Type 7, whereas other types were low and almost unchanged over time. Individuals with MAFLD had 19% and 38% increased mortality risks from all causes and cardiovascular disease, respectively. Among them, the metabolically unhealthy participants with normal weight demonstrated a 116% higher risk for all-cause mortality [hazard ratio (HR): 2.16, 95% CI: 1.52-3.08] and a 222% higher risk for cardiovascular mortality (HR: 3.22, 95% CI: 1.72-6.04). Interestingly, stratification and interaction analyses demonstrated a significant impact of metabolic parameters on the relationship between MAFLD and all-cause mortality.

CONCLUSIONS

In conclusion, our study identified an increase in MAFLD prevalence and a significant association between metabolic derangements in MAFLD and all-cause or cardiovascular mortality.

Global incidence and prevalence of nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) is a leading cause of liver disease worldwide. The estimated global incidence of NAFLD is 47 cases per 1,000 population and is higher among males than females. The estimated global prevalence of NAFLD among adults is 32% and is higher among males (40%) compared to females (26%). The global prevalence of NAFLD has increased over time, from 26% in studies from 2005 or earlier to 38% in studies from 2016 or beyond. The prevalence of NAFLD varies substantially by world region, contributed by differing rates of obesity, and genetic and socioeconomic factors. The prevalence of NAFLD exceeds 40% in the Americas and South-East Asia. The prevalence of NAFLD is projected to increase significantly in multiple world regions by 2030 if current trends are left unchecked. In this review, we discuss trends in the global incidence and prevalence of NAFLD and discuss future projections.

Screening for MAFLD: who, when and how?

Metabolic-associated fatty liver disease (MAFLD) is a highly prevalent disease with increasing prevalence worldwide. Currently, no universal screening methods have been standardized, even when this disease poses a major health burden. MAFLD as a spectrum of diseases can range from simple steatosis, and steatohepatitis to fibrosis and hepatocellular carcinoma. Its extra-hepatic manifestations are vast and include cardiovascular diseases, extra-hepatic malignancies, cognitive and respiratory alterations. Given its extensive damage targets as well as its high prevalence, timely identification of the high-risk population presenting metabolic dysfunction should undergo universal non-invasive screening methods, which can be carried out through blood tests, easy and effective imaging techniques, such as ultrasound, score calculation and general clinical information brought together from primary patient-physician contact.

Comprehensive Review of Cardiovascular Disease Risk in Nonalcoholic Fatty Liver Disease

Nonalcoholic Fatty Liver Disease (NAFLD) is a growing global phenomenon, and its damaging effects in terms of cardiovascular disease (CVD) risk are becoming more apparent. NAFLD is estimated to affect around one quarter of the world population and is often comorbid with other metabolic disorders including diabetes mellitus, hypertension, coronary artery disease, and metabolic syndrome. In this review, we examine the current evidence describing the many ways that NAFLD itself increases CVD risk. We also discuss the emerging and complex biochemical relationship between NAFLD and its common comorbid conditions, and how they coalesce to increase CVD risk. With NAFLD's rising prevalence and deleterious effects on the cardiovascular system, a complete understanding of the disease must be undertaken, as well as effective strategies to prevent and treat its common comorbid conditions.

Impact on Prevalence of the Application of NAFLD/MAFLD Criteria in Overweight and Normal Weight Patients

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is considered the hepatic manifestation of metabolic syndrome. Recently, the term metabolic dysfunction-associated fatty liver disease (MAFLD) has been proposed and adapted to body mass index (BMI). This study describes the impact on prevalence of the application of both criteria in overweight and lean patients.

METHODS

Patients who were evaluated for liver steatosis by transient elastography were included and divided according to BMI (≥25 kg/m² and <25 kg/m²) and classified as NAFLD or MAFLD, according to metabolic abnormalities. Differences in prevalence were evaluated applying both criteria. A multivariate analysis was performed to evaluate independent associations of metabolic abnormalities and liver steatosis in lean patients.

RESULTS

3847 patients were included. In overweight patients (61%), the prevalence NAFLD was 63.6% and 65.3% for MAFLD (p = 0.22). In contrast, the prevalence of MAFLD was lower (7.9% vs. 18.3%, p ≤ 0.001) in lean patients. In this group, higher age, fasting glucose, triglycerides, and waist circumference showed independent association with liver steatosis.

CONCLUSION

The application of NAFLD/MAFLD criteria did not show prevalence differences in overweight patients. With MAFLD criteria, the prevalence is lower in lean patients, but patients with high risk of progression of liver disease for steatosis were identified, according to their metabolic abnormalities.

Update on Non-Alcoholic Fatty Liver Disease-Associated Single Nucleotide Polymorphisms and Their Involvement in Liver Steatosis, Inflammation, and Fibrosis: A Narrative Review

Genetic factors are involved in the development, progression, and severity of NAFLD. Polymorphisms in genes regulating liver functions may increase liver susceptibility to NAFLD. Therefore, we conducted this literature study to present recent findings on NAFLD-associated polymorphisms from published articles in PubMed from 2016 to 2021. From 69 selected research articles, 20 genes and 34 SNPs were reported to be associated with NAFLD. These mutated genes affect NAFLD by promoting liver steatosis (PNPLA3, MBOAT7, TM2SF6, PTPRD, FNDC5, IL-1B, PPARGC1A, UCP2, TCF7L2, SAMM50, IL-6, AGTR1, and NNMT), inflammation (PNPLA3, TNF-α, AGTR1, IL-17A, IL-1B, PTPRD, and GATAD2A), and fibrosis (IL-1B, PNPLA3, MBOAT7, TCF7L2, GATAD2A, IL-6, NNMT, UCP, AGTR1, and TM2SF6). The identification of these genetic factors helps to better understand the pathogenesis pathways of NAFLD

Epidemiological and Genetic Aspects of NAFLD and NASH in Mexico

Content available: Author Interview and Audio Recording.

Reassessment of the Hispanic Disparity: Hepatic Steatosis Is More Prevalent in Mexican Americans Than Other Hispanics

Hepatic steatosis (HS) is a growing problem in adults worldwide, with racial/ethnic disparity in the prevalence of the disease. The purpose of this study was to characterize the racial/ethnic prevalence of the stages (normal/mild [S0/S1], moderate [S2], and severe [S3]) of HS in Mexican Americans and other Hispanics compared to other racial/ethnic groups. We analyzed data for 5,492 individuals 12 years and older from the newly released National Health and Nutrition Examination Survey 2017-2018, which is a representative sample of the US adult population. HS was diagnosed by FibroScan using controlled attenuation parameter values: S0, <238; S1, 238-259; S2, 260-290; S3, >290. We analyzed the data using the bivariate chi-squared test and multinomial regression. The prevalence of HS overall was 46.9% (S2,16.6%; S3, 30.3%). The prevalence of S3 was highest among Mexican Americans (42.8%), lowest among Blacks (21.6%), 27.6% in other Hispanics, and 30.6% in Whites (P < 0.05). Mexican Americans were about 2 times more likely than Whites to have S2 and S3, while other Hispanics showed no difference from Whites. In an adjusted model, the common risk factors of S2 and S3 were male sex, older ages, high waist-to-hip ratio, body mass index ≥25, and high triglycerides (P < 0.05). Other risk factors for S3 were hemoglobin A1c ≥5.7 and highly sensitive C-reactive protein ≥10 mg/dL (P < 0.05). Conclusion: Our study challenges the paradigm that HS is higher in Hispanics overall; rather, our data show that HS is higher in Mexican Americans and not non-Mexican American Hispanics.

Long-standing effect of cholecystectomy in patients with metabolic-associated fatty liver disease

OBJECTIVE

The role of cholecystectomy as a risk factor in patients with metabolic-associated fatty liver disease (MAFLD) remains unclear. This study aimed to investigate if long-standing cholecystectomy is associated with advanced liver fibrosis and cirrhosis in patients with recently diagnosed MAFLD.

METHODS

A retrospective observational study was performed in four hospitals in Mexico including patients with recently diagnosed MAFLD and a history of cholecystectomy. Subjects were divided into those with cholecystectomy ≥6 months before MAFLD diagnosis (ChBM), and those with cholecystectomy at the time of MAFLD diagnosis (ChAM). Odds ratios (OR) for the association of advanced liver fibrosis and cirrhosis with the timing of cholecystectomy were calculated.

RESULTS

Mean age of 211 participants was 49.06 ± 15.12 years and the majority were female (72.5%). Patients from the ChBM (n = 70) group were significantly older (53.14 vs. 47.03 years; P = 0.003), had higher BMI (30.54 vs. 28.52 kg/m2; P = 0.011) and lower platelet count (236.23 vs. 266.72 × 103/µL; P = 0.046) compared with patients from ChAM group (n = 141). In multivariable-adjusted analysis, age (OR = 2.37; P = 0.024), dyslipidemia (OR = 4.28; P = 0.005) and severe liver fibrosis (OR = 4.68; P = 0.0) were independent risk factors associated with long-standing cholecystectomy.

CONCLUSION

Patients with long-standing cholecystectomy (≥6 months) are at increased risk of severe liver fibrosis and cirrhosis at the time of MAFLD diagnosis compared to those with recently done cholecystectomy. Advanced age (>50 years) and dyslipidemia are also commonly found in these subjects.

Association of PNPLA3 I148M with Liver Disease Biomarkers in Latinos

INTRODUCTION

Liver disease accounts for approximately 2 million deaths per year worldwide. The majority of liver diseases are due to complications of cirrhosis, viral hepatitis, and hepatocellular carcinoma. Increased levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) may indicate liver disease. Moreover, there are additional noninvasive liver fibrosis indices that help to estimate liver damage, including AST-to-ALT ratio, AST-to-platelet ratio index (APRI), fibrosis-4 (FIB-4) score, and nonalcoholic fatty liver disease (NAFLD) fibrosis score. The aims of the present study were to (1) perform an association analysis of the patatin-like phospholipase domain containing 3 (PNPLA3) I148M (rs738409) variant with ALT, AST, and various liver fibrosis indices, and (2) determine whether there are gender-related differences in these associations.

METHODS

We obtained demographic, anthropometric, and metabolic phenotypes from Latino adult participants (n = 503, 64% female, 36.4 ± 0.5 years) from the Arizona Insulin Resistance (AIR) registry. SNP genotyping of I148M was performed using the TaqMan allelic discrimination assay. We used linear regression for the association analyses of the genotypes with ALT, AST, and the various liver fibrosis indices. We included genotype, age, body mass index, and alcohol status in the linear regression model.

RESULTS

The variant I148M was in Hardy-Weinberg equilibrium, with genotype distribution: non-risk CC 118, heterozygous CG 246, and risk GG 139. The G allele was significantly associated with increased ALT and AST levels (p = 7.8 × 10-7 and p = 9.7 × 10-6, respectively). Moreover, we showed that the G allele was significantly associated with higher APRI (p = 3.7 × 10-7) and FIB-4 score (p = 4.1 × 10-3). When we analyzed the data by gender, we observed similar significant trends for ALT, AST, and APRI (all, p < 0.01). In females, the G allele was significantly associated with increased FIB-4 score (p = 6.9 × 10-3), which was not observed in the males (p > 0.05). There was no association of the I148M variant with AST/ALT ratio nor NAFLD risk score, whether analyzed in all adults or by gender.

DISCUSSION/CONCLUSION

Our findings provide additional evidence of an association of PNPLA3 I148M with several liver disease biomarkers in male and female Latinos residing in the Southwest of the United States.

The PNPLA3 rs738409 Variant but not MBOAT7 rs641738 is a Risk Factor for Nonalcoholic Fatty Liver Disease in Obese U.S. Children of Hispanic Ethnicity

PURPOSE

The rs641738 C>T in membrane-bound O-acyltransferase domain-containing protein 7 (MBOAT7) is implicated, along with the rs738409 C>G polymorphism in patatin-like phospholipase domain-containing protein 3 (PNPLA3), in nonalcoholic fatty liver disease (NAFLD). The association of these polymorphisms and NAFLD are investigated in Hispanic children with obesity.

METHODS

Obese children with and without NAFLD were enrolled at a pediatric tertiary care health system and genotyped for MBOAT7 rs641738 C>T and PNPLA3 rs738409 C>G. NAFLD was characterized by the ultrasonographic presence of hepatic steatosis along with persistently elevated liver enzymes. Genetic variants and demographic and biochemical data were analyzed for the effects on NAFLD.

RESULTS

Among 126 enrolled subjects, 84 in the case group had NAFLD and 42 in the control group did not. The two groups had similar demographic distribution. NAFLD was associated with abnormal liver enzymes and elevated triglycerides and cholesterol (p<0.05). Children with NAFLD had higher percentage of PNPLA3 GG genotype at 70.2% versus 31.0% in non-NAFLD, and lower MBOAT7 TT genotype at 4.8% versus 16.7% in non-NAFLD (p<0.05). PNPLA3 rs738409 C>G had an additive effect in NAFLD; however, MBOAT7 rs641738 C>T had no effects alone or synergistically with PNPLA3 polymorphism. NAFLD risk increased 3.7-fold in subjects carrying PNPLA3 GG genotype and decreased in MBOAT7 TT genotype.

CONCLUSION

In Hispanic children with obesity, PNPLA3 rs738409 C>G polymorphism increased the risk for NAFLD. The role of MBOAT7 rs641738 variant in NAFLD is less evident.

Dietary consumption and serum pattern of bioactive fatty acids in NAFLD patients

INTRODUCTION AND OBJECTIVES

Nonalcoholic fatty liver disease (NAFLD) is the hepatic manifestation of metabolic syndrome. Some dietary fatty acids have showed different bioactive functions in metabolic syndrome. The aim of this study is to determine the dietary consumption patterns and serum percentage of bioactive fatty acids in NAFLD patients.

PATIENTS AND METHODS

Cross-sectional study with NAFLD patients and non-NAFLD patients. Dietary consumption of bioactive fatty acids was assessed by a food frequency questionnaire. NAFLD and liver fibrosis were diagnosed by transient elastography. The identification of serum bioactive fatty acids was achieved by gas chromatography-mass spectrometry (%). Bioactive fatty acids consumption was correlated with NAFLD clinical characteristics with the Spearman correlation analysis.

RESULTS

A total of 299 patients were included, whose mean of age and body mass index were 44.2±9.9 years and 25.9±3.8kg/m², respectively. The consumption of bioactive fatty acids was no different regarding the presence of NAFLD; however, the consumption of stearic and linoleic fatty acids was higher in relation with NAFLD severity (p≤0.05). The consumption of myristic acid was higher in patients with fibrosis (p=0.02). Serum percentage and dietary consumption did not show correlations.

CONCLUSION

Dietary consumption of bioactive fatty acids is different according to NAFLD severity. Individualized diets according to NAFLD severity could be successful in order to prevent liver injury-related outcomes.

Gut Microbiota in Metabolic-associated Fatty Liver Disease and in Other Chronic Metabolic Diseases

The gut microbiome plays a key role in the health-disease balance in the human body. Although its composition is unique for each person and tends to remain stable throughout lifetime, it has been shown that certain bacterial patterns may be determining factors in the onset of certain chronic metabolic diseases, such as type 2 diabetes mellitus (T2DM), obesity, metabolic-associated fatty liver disease (MAFLD), and metabolic syndrome. The gut-liver axis embodies the close relationship between the gut and the liver; disturbance of the normal gut microbiota, also known as dysbiosis, may lead to a cascade of mechanisms that modify the epithelial properties and facilitate bacterial translocation. Regulation of gut microbiota is fundamental to maintaining gut integrity, as well as the bile acids composition. In the present review, we summarize the current knowledge regarding the microbiota, bile acids composition and their association with MAFLD, obesity, T2DM and metabolic syndrome.

Non-Alcoholic Steatohepatitis: A Review of Its Mechanism, Models and Medical Treatments

Non-alcoholic steatohepatitis (NASH) develops from non-alcoholic fatty liver disease (NAFLD). Currently, around 25% of the population is estimated to have NAFLD, and 25% of NAFLD patients are estimated to have NASH. NASH is typically characterized by liver steatosis inflammation, and fibrosis driven by metabolic disruptions such as obesity, diabetes, and dyslipidemia. NASH patients with significant fibrosis have increased risk of developing cirrhosis and liver failure. Currently, NASH is the second leading cause for liver transplant in the United States. More importantly, the risk of developing hepatocellular carcinoma from NASH has also been highlighted in recent studies. Patients may have NAFLD for years before progressing into NASH. Although the pathogenesis of NASH is not completely understood, the current “multiple-hits” hypothesis suggests that in addition to fat accumulation, elevated oxidative and ER stress may also drive liver inflammation and fibrosis. The development of clinically relevant animal models and pharmacological treatments for NASH have been hampered by the limited understanding of the disease mechanism and a lack of sensitive, non-invasive diagnostic tools. Currently, most pre-clinical animal models are divided into three main groups which includes: genetic models, diet-induced, and toxin + diet-induced animal models. Although dietary models mimic the natural course of NASH in humans, the models often only induce mild liver injury. Many genetic and toxin + diet-induced models rapidly induce the development of metabolic disruption and serious liver injury, but not without their own shortcomings. This review provides an overview of the “multiple-hits” hypothesis and an evaluation of the currently existing animal models of NASH. This review also provides an update on the available interventions for managing NASH as well as pharmacological agents that are currently undergoing clinical trials for the treatment of NASH.

Ethnic influence on nonalcoholic fatty liver disease prevalence and lack of disease awareness in the United States, 2011-2016

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) is a rising global disease associated with clinical and economic burdens.

OBJECTIVES

We aimed to quantify NAFLD prevalence and awareness to provide stakeholders necessary information to combat NAFLD burden.

METHODS

This study utilizes data from the National Health and Nutrition Examination Survey 2011-2016 and included 4538 adult participants who did not have heavy drinking or viral hepatitis history. The US fatty liver index defined NAFLD and NAFLD fibrosis score defined fibrosis. NAFLD awareness was captured by questionnaire.

RESULTS

Amongst the study population of 4538 persons, NAFLD prevalence was 32.5%, lowest in non-Hispanic Blacks (18.0%) and Asians (18.1%), highest amongst Mexican Americans (48.4%). Within the NAFLD group, advanced fibrosis was highest in non-Hispanic Blacks (28.5%) and lowest amongst non-Hispanic Asians (2.7%). Of the 1473 (97.5%) NAFLD participants who answered NAFLD awareness question, 90% visited a healthcare centre at least once in the past year, but only 5.1% were aware of having NAFLD. On weighted population estimates, 77.33 million persons had NAFLD, 17.63 million had advanced fibrosis, and 73.39 million NAFLD participants were not aware of having NAFLD.

CONCLUSIONS

Of 77.33 million people in the United States have NAFLD with 17.63 million having advanced fibrosis, with lowest prevalence in non-Hispanic Asians and highest in Mexican Americans. A conundrum exists amongst non-Hispanic Blacks who have low NAFLD prevalence but highest prevalence of advanced fibrosis. Awareness of NAFLD was low across all ethnicities. Effort is needed to improve disease awareness whilst addressing NAFLD clinical burden across ethnicities.

Prevalence of liver fibrosis in an unselected general population with high prevalence of obesity and diabetes mellitus. Time for screening?

INTRODUCTION

Cirrhosis and liver cancer are currently common causes of death worldwide. The global epidemic of obesity has increased the incidence of nonalcoholic fatty liver disease (NAFLD) and cirrhosis in recent years. Advanced fibrosis increases the morbimortality rate in NAFLD. The Mexican population has one of the highest prevalence of obesity and diabetes mellitus (DM) worldwide.

AIM

To determine the prevalence of advanced liver fibrosis in Mexican general population.

METHODS

Adult individuals, without a history of liver disease nor heavy alcohol consumption were randomly sampled from 20,919 participants of a health and nutrition survey applied to the general population. Clinical and laboratory evaluations were performed to calculate the NAFLD fibrosis score (NFS) (an extensively validated non-invasive method). Two cut-off points were used. Advanced fibrosis was defined as a result >0.676.

RESULTS

In total 695 individuals were included. The mean age was 47.8±16.4. The majority were between 20 and 50 years (59%), 70.2% were female, 35.5% showed obesity and 15.8% DM. The 93% had normal serum ALT. Based on the NFS results, 56 individuals (8.1%) had a high probability of fibrosis. Most patients from this subgroup showed normal serum ALT (92.9%), 89.3% were >45yr. old, 52% were obese and 27% suffered from DM.

CONCLUSIONS

Based on these results, 8.1% of Mexican general population without a history of liver disease is at high risk of having advanced liver fibrosis and complications and death derived from cardiovascular disease and cirrhosis. Most of them showed normal ALT serum levels.

Epidemiology of chronic liver diseases in the USA in the past three decades

OBJECTIVE

Given significant advances in treatment of viral hepatitis and the growing epidemic of obesity, the burden of the different types of liver diseases in the USA may be changing. Our aim was to assess the shift in the prevalence of different liver disease aetiologies in the USA over the past three decades.

DESIGN

National Health and Nutrition Examination Surveys (NHANES; cross-sectional 1988-1994 and 1999-2016) were used.

RESULTS

A total of 58 731 adults from NHANES (1988-2016) were included. Over the study period, the prevalence of chronic hepatitis B and alcoholic liver disease remained stable: 0.3%-0.4% and 0.8%-1.0%, respectively (p>0.05). The prevalence of chronic hepatitis C decreased nearly twofold: 1.6% in 1988-1994 to 0.9% in 2013-2016 (p=0.03). In contrast, the prevalence of non-alcoholic fatty liver disease (NAFLD; by US-Fatty Liver Index) increased from 20.0% (1988-1994) to 28.3% (1999-2004) to 33.2% (2009-2012) and 31.9% (2013-2016) (p<0.0001). Furthermore, steady increases were observed in the rates of obesity (22.2% in 1988-1994 to 31.0% in 1999-2004 to 38.9% in 2013-2016), type 2 diabetes mellitus (T2DM) (from 7.2% to 8.2% to 13.5% same years), insulin resistance and hypertension (all p<0.0001). Yearly trend analyses showed that the only LD with consistently increasing prevalence was NAFLD (trend p=0.01). Multivariable regression analysis showed that obesity (OR 10.4; 95% CI 9.5 to 11.3) and T2DM (OR 3.7; 95% CI 3.2 to 4.2) were the major independent predictors of NAFLD.

CONCLUSIONS

Over the past 30 years in the USA, NAFLD is the only liver disease with growing prevalence, synchronous with the increasing rates of obesity and T2DM.

Dyslipidemia as a risk factor for liver fibrosis progression in a multicentric population with non-alcoholic steatohepatitis

Background: Nonalcoholic fatty liver disease (NAFLD) is a serious worldwide health problem, with an estimated global prevalence of 24%; it has a notable relationship with other metabolic disorders, like obesity and type 2 diabetes mellitus (T2DM). Nonalcoholic steatohepatitis (NASH) is one of the most important clinical entities of NAFLD, which is associated with an increased risk of progression to liver cirrhosis and hepatocellular carcinoma (HCC). Mexico is one of the countries with the highest prevalence of metabolic diseases; therefore, we sought to investigate the impact that these clinical entities have in the progression to advanced fibrosis in Mexican patients with NASH. Methods: We performed a multicenter retrospective cross-sectional study, from January 2012 to December 2017. A total of 215 patients with biopsy-proven NASH and fibrosis were enrolled. NASH was diagnosed according NAS score and liver fibrosis was staged by the Kleiner scoring system. For comparing the risk of liver fibrosis progression, we divided our sample into two groups. Those patients with stage F0-F2 liver fibrosis were included in the group with non-significant liver fibrosis (n=178) and those individuals with F3-F4 fibrosis were included in the significant fibrosis group (n=37). We carried out a multivariate analysis to find risk factors associated with liver fibrosis progression. Results: From the 215 patients included, 37 had significant liver fibrosis (F3-4). After logistic regression analysis T2DM (p=0.044), systemic arterial hypertension (p=0.014), cholesterol (p=0.041) and triglycerides (p=0.015) were the main predictor of advanced liver fibrosis. Conclusions: In a Mexican population, dyslipidemia was the most important risk factor associated with advanced liver fibrosis and cirrhosis.

The Mexican consensus on nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) affects nearly one third of the population worldwide. Mexico is one of the countries whose population has several risk factors for the disease and its prevalence could surpass 50%. If immediate action is not taken to counteract what is now considered a national health problem, the medium-term panorama will be very bleak. This serious situation prompted the Asociación Mexicana de Gastroenterología and the Asociación Mexicana de Hepatología to produce the Mexican Consensus on Fatty Liver Disease. It is an up-to-date and detailed review of the epidemiology, pathophysiology, clinical forms, diagnosis, and treatment of the disease, whose aim is to provide the Mexican physician with a useful tool for the prevention and management of nonalcoholic fatty liver disease.

Prevalence of Nonalcoholic Fatty Liver Disease in the Female Population

There is a paucity of recent data about the epidemiology and long‐term outcomes of nonalcoholic fatty liver disease (NAFLD) in the female population. Our aim was to assess the prevalence, risk factors, and mortality of NAFLD in female adults of the United States. Data from the National Health and Nutrition Examination Survey (NHANES) III and NHANES 1999‐2014 were used. NAFLD status was determined by the U.S. Fatty Liver Index (US‐FLI) in the absence of other liver diseases and excessive alcohol consumption. The prevalence rates, risk factors, and 5‐year all‐cause and cardiovascular mortality were determined in women with NAFLD. The most recent prevalence of NAFLD among female adults (2007‐2014) in the United States was 24.4% (95% confidence interval [CI], 22.48‐26.33). Prevalence was higher among women >44 years of age and those with body mass index ≥30 kg/m². In addition, the average age of the female population with NAFLD has decreased over time. The fully adjusted odds ratios in women with NAFLD compared to those without NAFLD were 1.48 (95% CI, 1.20‐1.82) for cardiovascular disease (CVD), 1.89 (95% CI, 1.42‐2.52) for atherosclerotic cardiovascular disease (ASCVD) score ≥7.5%, and 1.76 (95% CI, 1.37‐2.25) for either CVD or ASCVD ≥7.5%. The 5‐year mortality for female adults with NAFLD was significantly higher than for those without NAFLD (adjusted hazard ratio, 1.48; 95% CI, 1.07‐2.05). Among women with NAFLD, those with ASCVD ≥7.5% had significantly higher 5‐year all‐cause mortality and CVD mortality. Conclusion: The prevalence of NAFLD in female NHANES participants from the United States has continued over recent years. In the female population with NAFLD, ASCVD ≥7.5% is an independent predictor of overall and cardiac‐specific mortality.

NAFLD is growing in the female population in the U.S. NAFLD is associated with metabolic risk factors and increases the risk of CVD and mortality. Detection of NAFLD in females consider a serious risk threat that needs to be addressed to potentially improve their long‐term outcomes.

Global Epidemiology, Prevention, and Management of Hepatocellular Carcinoma

The incidence rate of hepatocellular carcinoma (HCC) is rising. It is one of the most common cancers worldwide and accounts for substantial morbidity and mortality. Chronic hepatitis B virus (HBV) infection, chronic hepatitis C virus (HCV) infection, and nonalcoholic fatty liver disease (NAFLD) are the most important etiologies of HCC, and effective screening and management strategies are crucial to reduce the HCC risk. For HBV, which accounts for the majority of HCC cases, most infections were acquired via perinatal and early horizontal transmission. Universal vaccination of newborns has led to a decline in HCC incidence compared with the pre-vaccination era. Effective antiviral therapies with nucleos(t)ide analogues or pegylated interferon reduced the incidence of HCC. For HCV, the emergence of effective direct-acting antiviral (DAA) agents has substantially improved cure rates; therefore all patients with HCV should be considered for DAA treatment. The most important obstacle in eliminating HCV is access to therapy. For NAFLD, the global incidence is increasing rapidly, thus its impact on HCC incidence may be explosive. Progression to HCC in NAFLD happens particularly in those with nonalcoholic steatohepatitis (NASH) and exacerbated by metabolic syndrome, or PNPLA3 gene polymorphism. Lifestyle changes are imperative while drug therapy has yet to demonstrate substantive protective effects on HCC prevention. For management of HCC, early diagnosis via imaging surveillance among persons with HCC risk factors remains the most important strategy to identify early-stage disease appropriate for resection or transplantation.