NAFLD: Challenges and opportunities to address the public health problem in Latin America

The burden of liver disease in Latin America

Liver disease poses a substantial burden in Latin America. This burden is primarily attributed to a high level of alcohol consumption and the increasing prevalence of risk factors associated with metabolic dysfunction-associated steatotic liver disease (MASLD), such as sedentary lifestyles, easy access to ultra-processed foods, obesity, and type 2 diabetes mellitus. These epidemiological trends are cause for concern, especially considering that there are significant challenges in addressing them due to disparities in access to liver disease screening and care. In this article, we aim to provide an overview of the current situation regarding liver disease in Latin America. We also discuss recent multinational proposals designed to address the growing MASLD burden via its integration into existing non-communicable diseases policies, at both local and global levels. Additionally, we emphasize the urgent need to establish effective public health policies that target both MASLD risk factors and excessive alcohol consumption. Furthermore, we discuss the development of liver transplantation programs, areas for improvement in medical education and research capabilities, and how the fostering of extensive collaboration among all stakeholders is crucial for addressing liver disease in the region.

The intersection between alcohol-related liver disease and nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) and alcohol-related liver disease (ALD) are the leading causes of chronic liver disease worldwide. NAFLD and ALD share pathophysiological, histological and genetic features and both alcohol and metabolic dysfunction coexist as aetiological factors in many patients with hepatic steatosis. A diagnosis of NAFLD requires the exclusion of significant alcohol consumption and other causes of liver disease. However, data suggest that significant alcohol consumption is often under-reported in patients classified as having NAFLD and that alcohol and metabolic factors interact to exacerbate the progression of liver disease. In this Review, we analyse existing data on the interaction between alcohol consumption and metabolic syndrome as well as the overlapping features and differences in the pathogenesis of ALD and NAFLD. We also discuss the clinical implications of the coexistence of alcohol consumption, of any degree, in patients with evidence of metabolic derangement as well as the use of alcohol biomarkers to detect alcohol intake. Finally, we summarize the evolving nomenclature of fatty liver disease and describe a recent proposal to classify patients at the intersection of NAFLD and ALD. We propose that, regardless of the presumed aetiology, patients with fatty liver disease should be evaluated for both metabolic syndrome and alcohol consumption to enable better prognostication and a personalized medicine approach.

Epidemiology and risk factors for histopathologic characteristics of non-alcoholic fatty liver disease in South America

BACKGROUND

The burden of non-alcoholic fatty liver disease (NAFLD) in South America is among the highest in the world. However, the epidemiology and risk factors for NAFLD are insufficiently described in the region.

AIM

To explore the associations between clinical characteristics and histopathological features of NAFLD METHODS: This was a descriptive study of 2722 patients with NAFLD from 8 medical centres across 5 South American countries. We collected clinical, biochemical and histopathological data using a templated chart. Fibrosis was assessed by elastography or fibrosis scores and confirmed with biopsy when available. We examined associations between histopathological features and clinical characteristics with logistic regression models. Models were adjusted for country, age and sex.

RESULTS

The median age was 53 years (IQR: 41-62), and 63% were women. Subjects from Brazil had the highest body mass index at 42 kg/m2 . Sixty-seven percent had dyslipidemia, 46% had obesity, 30% had hypertension, 17% had type 2 diabetes mellitus (T2DM) and 34% had metabolic syndrome. Biopsy reports were available for 948 (35%), of which 58% showed fibrosis, 91% steatosis and 65% inflammation; 25% showed significant fibrosis and 27% severe steatosis. Metabolic syndrome, T2DM and hypertension were significantly associated with significant fibrosis (OR = 1.94, p < 0.001; OR = 2.93, p < 0.001 and OR = 1.60, p = 0.003, respectively), severe steatosis (OR = 2.05, p < 0.001; OR = 1.91, p = 0.001 and OR = 2.17, p < 0.001, respectively) and liver inflammation (OR = 1.66, p = 0.007; OR = 2.00, p = 0.002; OR = 1.62, p = 0.001, respectively).

CONCLUSIONS

In the largest NAFLD cohort study to date from South America, metabolic syndrome, hypertension and T2DM were independently associated with significant fibrosis, severe steatosis, and inflammation. The prevalence of T2DM was lower than the reported global prevalence.

Research Priorities for Precision Medicine in NAFLD

NAFLD is a multisystem condition and the leading cause of chronic liver disease globally. There are no approved NAFLD-specific dugs. To advance in the prevention and treatment of NAFLD, there is a clear need to better understand the pathophysiology and genetic and environmental risk factors, identify subphenotypes, and develop personalized and precision medicine. In this review, we discuss the main NAFLD research priorities, with a particular focus on socioeconomic factors, interindividual variations, limitations of current NAFLD clinical trials, multidisciplinary models of care, and novel approaches in the management of patients with NAFLD.

Nonalcoholic Fatty Liver Disease in Latin America and Australia

The epidemiologic and demographical features of nonalcoholic fatty liver disease (NAFLD) vary significantly across countries and continents. In this review, we analyze current data regarding prevalence of NAFLD in Latin America and Caribbean and Australia and review some peculiarities found in these regions. We stress the need of greater awareness of NAFLD and the development of cost-effective risk stratification strategies and clinical care pathways of the disease. Finally, we highlight the need of effective public health policies to control the main risk factors for NAFLD.

Geographical similarity and differences in the burden and genetic predisposition of NAFLD

NAFLD has become a major public health problem for more than 2 decades with a growing prevalence in parallel with the epidemic of obesity and type 2 diabetes (T2D). The disease burden of NAFLD differs across geographical regions and ethnicities. Variations in prevalence of metabolic diseases, extent of urban-rural divide, dietary habits, lifestyles, and the prevalence of NAFLD risk and protective alleles can contribute to such differences. The rise in NAFLD has led to a remarkable increase in the number of cases of cirrhosis, hepatocellular carcinoma, hepatic decompensation, and liver-related mortality related to NAFLD. Moreover, NAFLD is associated with multiple extrahepatic manifestations. Most of them are risk factors for the progression of liver fibrosis and thus worsen the prognosis of NAFLD. All these comorbidities and complications affect the quality of life in subjects with NAFLD. Given the huge and growing size of the population with NAFLD, it is expected that patients, healthcare systems, and the economy will suffer from the ongoing burden related to NAFLD. In this review, we examine the disease burden of NAFLD across geographical areas and ethnicities, together with the distribution of some well-known genetic variants for NAFLD. We also describe some special populations including patients with T2D, lean patients, the pediatric population, and patients with concomitant liver diseases. We discuss extrahepatic outcomes, patient-reported outcomes, and economic burden related to NAFLD.

Liraglutide on type 2 diabetes mellitus with nonalcoholic fatty liver disease: A systematic review and meta-analysis of 16 RCTs

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) is a common comorbidity of type 2 diabetes mellitus (T2DM). Our aim is to investigate the effects of liraglutide on T2DM with NAFLD.

METHODS

Relevant articles published from the earliest publication to March 2022 were selected from several databases. The Cochrane Collaboration's RevMan software was used for the analysis.

RESULTS

Sixteen studies are selected for this meta-analysis, which includes totally 634 patients in the treatment group and 630 patients in the control group. As a result, 14 studies show that fasting plasma glucose levels of the experimental group are lower than that of the control group; 15 studies show that glycosylated hemoglobin A1c levels of the experimental group are lower than that of the control group; 13 studies show that triglyceride levels of the experimental group are lower than that of the control group; twelve studies show that total cholesterol levels of the experimental group are lower than that of the control group; 10 studies show that alanine aminotransferase levels of the experimental group is lower than that of the control group; 10 studies show that no significant difference in changes in aspartate transaminase between 2 groups; 13 studies show that low density lipoprotein cholesterol levels of the experimental group is lower than that of the control group; 9 studies show that no significant difference in changes in high density lipoprotein cholesterol between 2 groups; 7 studies mentioned adverse effects and the difference is significant.

CONCLUSION

Liraglutide is potentially curative for T2DM with NAFLD.

Non-alcoholic fatty liver disease prevalence in Latin America: A systematic review and meta-analysis

Non-alcoholic fatty liver disease (NAFLD) produces high morbidity and mortality rates. Its worldwide prevalence is 25%, but evidence from Latin America (LA) is lacking. We aimed to estimate the prevalence of NAFLD in the adult population of LA. We conducted a systematic review and meta-analysis. Data were collected from OVID, Cochrane Library and LILACS search engines. We used terms related to NAFLD and LA countries. Observational studies in adults who were born and live in LA were included. Two reviewers evaluated the articles, extracted data and assessed the risk of bias. Discrepancies were resolved by consensus or by a third reviewer. A validated tool was used to assess risk of bias. We found and analyzed 19 articles (n=5625). The prevalence in the general and captive population found was 24%. Populations with type 2 diabetes mellitus or obesity had a higher mean prevalence that reached 68%. We concluded that the average prevalence of NAFLD in LA is around 24%. Among high-risk groups, this value increases to 68%. Further studies in the general population using appropriate designs are required for an accurate estimate of the prevalence of NAFLD in LA.

Worldwide long-term trends in the incidence of nonalcoholic fatty liver disease during 1990–2019: A joinpoint and age-period-cohort analysis

Background

Non-alcoholic fatty liver disease (NAFLD) was previously a neglected disease that is now becoming a worldwide pandemic. A better understanding of its incidence and long-term trends will help to increase public awareness of the disease and the development of future prevention strategies.

Methods

The incidence rates of NAFLD during 1990–2019 were collected from the Global Burden of Disease Study 2019 database according to the following parameters: sex, age, socio-demographic index, and geographical region. Estimated annual percentage changes and joinpoint models were used to assess the long-term trend of NAFLD, and an age-period-cohort model was used to assess the extents of the age, period, and cohort effects.

Results

Adult males, postmenopausal females, Latin American populations, and people in developing countries had a high risk of developing NAFLD. The joinpoint model indicated a new trend of increasing NAFLD incidence in 2005. Age was a risk factor affecting NAFLD incidence, with this effect increasing in more-recent periods. Younger birth cohorts had lower risks of NAFLD.

Conclusions

Recent prevention measures for NAFLD have achieved good initial results. However, it remains a high priority to increase the public awareness of this condition, develop its diagnostic criteria, identify cost-effective screening methods, and seek policy support to act against NAFLD, which will be a major public health problem in the future.

Circulating bile acid concentrations and non-alcoholic fatty liver disease in Guatemala

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is a major liver disease worldwide. Bile acid dysregulation may be a key feature in its pathogenesis and progression.

AIMS

To characterise the relationship between bile acid levels and NAFLD at the population level METHODS: We conducted a cross-sectional study in Guatemala in 2016 to examine the prevalence of NAFLD. Participants (n = 415) completed questionnaires, donated blood samples and had a brief medical exam. NAFLD was determined by calculation of the fatty liver index. The levels of 15 circulating bile acids were determined by LC-MS/MS. Adjusted prevalence odds ratios (POR_adj ) and 95% CI were calculated to examine the relationships between bile acid levels (in tertiles) and NAFLD.

RESULTS

Persons with NAFLD had significantly higher levels of the conjugated primary bile acids glycocholic acid (GCA) (POR_{adj T3 vs T1}  = 1.85), taurocholic acid (TCA) (POR_{adj T3 vs T1}  = 2.45) and taurochenodeoxycholic acid (TCDCA) (POR_{adj T3 vs T1}  = 2.10), as well as significantly higher levels the unconjugated secondary bile acid, deoxycholic acid (DCA) (POR_{adj T3 vs T1}  = 1.78) and its conjugated form, taurodeoxycholic acid (TDCA) (POR_{adj T3 vs T1}  = 1.81).

CONCLUSIONS

The bile acid levels of persons with and without NAFLD differed significantly. Among persons with NAFLD, higher levels of the conjugated forms of CA (i.e. GCA, TCA) and the secondary bile acids that derive from CA (i.e. DCA, TDCA) may indicate there is hepatic overproduction of CA, which may affect the liver via aberrant signalling mediated by the bile acids.

Liver Diseases in Latin America: Current Status, Unmet Needs, and Opportunities for Improvement

Purpose of review

To assess the current challenges regarding liver diseases, including the burden of disease, access to care, screening, and treatment needs in Latin America.

Recent findings

Latin America is a region with a rich multicultural heritage and important socioeconomic differences. The burden of liver diseases is high and mainly determined by a high level of alcohol intake and the surge of risk factors associated with NAFLD (i.e., sedentary lifestyles, broader access to highly processed foods, obesity, and type 2 diabetes mellitus). Hepatotropic viruses also play a role in the development of chronic liver diseases, although their comparative frequency has been decreasing over the last decades. There are important disparities in access to screening and treatment for liver diseases in Latin America, which are reflected in low access to critical treatments such as direct-acting antiviral agents and drugs to treat hepatocellular carcinoma. Also, important barriers to liver transplantation are present in multiple countries, including a low deceased donors’ rate and a lack of availability in several countries (especially in Central America). Our region also has disadvantages in research and education in liver diseases, which limits regional academic development and improvement in quality of care of liver diseases.

Summary

In order to tackle an increasing health burden due to liver diseases, Latin America urgently needs tailored interventions aiming to control the main risk factors for these disorders through the establishment of effective public health policies. Also, development of liver transplantation programs and improvement of medical education and research capabilities as well as extensive collaboration between all stakeholders are keys to address the liver disease agenda in the region.

Editorial: International Consensus Recommendations to Replace the Terminology of Non-Alcoholic Fatty Liver Disease (NAFLD) with Metabolic-Associated Fatty Liver Disease (MAFLD)

In 2020, international consensus guidelines recommended the renaming of non-alcoholic fatty liver disease (NAFLD) to metabolic-associated fatty liver disease (MAFLD), supported by diagnostic criteria. MAFLD affects up to 25% of the global population. However, the rates of MAFLD are likely to be underestimated due to the increasing prevalence of type 2 diabetes mellitus (T2DM) and obesity. Within the next decade, MAFLD has been projected to become a major cause of cirrhosis and hepatocellular carcinoma (HCC) worldwide, as well as the most common indication for liver transplantation in the US. This transition in terminology and clinical criteria may increase momentum and clinical evidence at multiple levels, including patient diagnosis, management, and care, and provide the basis for new research areas and clinical development for therapeutics. The diagnostic criteria for MAFLD are practical, simple, and superior to the existing NAFLD criteria for identifying patients at increased risk of developing progressive liver disease. This Editorial aims to present the historical evolution of the terminology for fatty liver disease and the advantages of diagnosis, patient management, and future research on MAFLD.