Non-alcoholic fatty liver disease and increased risk of incident extrahepatic cancers: a meta-analysis of observational cohort studies

Nonalcoholic fatty liver disease from a primary care perspective

Nonalcoholic fatty liver disease (NAFLD) affects up to one-third of the US population. Approximately one-fifth of patients with NAFLD have nonalcoholic steatohepatitis (NASH), characterized by hepatocyte damage and inflammation with or without fibrosis. NASH leads to greater risk of liver-related complications and liver-related mortality, with the poorest outcomes seen in patients with advanced fibrosis. NASH is also associated with other metabolic comorbidities and conveys an increased risk of adverse cardiovascular outcomes and extrahepatic cancers. Despite its high prevalence, NAFLD is frequently underdiagnosed. This is a significant concern, given that early diagnosis of NAFLD is a key step in preventing progression to NASH. In this review, we describe the clinical impact of NASH from the perspective of both the clinician and the patient. In addition, we provide practical guidance on the diagnosis and management of NASH for primary care providers, who play a pivotal role in the frontline care of patients with NASH, and we use case studies to illustrate real-world scenarios encountered in the primary care setting.

The role of hepatokines in NAFLD

Non-alcoholic fatty liver disease (NAFLD) is not only a consequence of insulin resistance, but it is also an important cause of insulin resistance and major non-communicable diseases (NCDs). The close relationship of NAFLD with visceral obesity obscures the role of fatty liver from visceral adiposity as the main pathomechanism of insulin resistance and NCDs. To overcome this limitation, in analogy to the concept of adipokines, in 2008 we introduced the term hepatokines to describe the role of fetuin-A in metabolism. Since then, several other hepatokines were tested for their effects on metabolism. Here we address the dysregulation of hepatokines in people with NAFLD. Then, we discuss pathophysiological mechanisms of cardiometabolic diseases specifically related to NAFLD by focusing on hepatokine-related organ crosstalk. Finally, we propose how the determination of major hepatokines and adipokines can be used for pathomechanism-based clustering of insulin resistance in NAFLD and visceral obesity to better implement precision medicine in clinical practice.

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

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

Nonalcoholic Fatty Liver Disease

Nonalcoholic fatty liver disease (NAFLD) is a global public health problem. NAFLD is bidirectionally correlated with metabolic syndrome, which includes obesity, type 2 diabetes, hypertension, and dyslipidemia as major components. The presence of metabolic syndrome is associated with a higher prevalence of NAFLD, and vice versa. Also, the presence of metabolic syndrome in patients with NAFLD has been linked to a higher risk of cardiovascular diseases, liver-related complications, extrahepatic malignancies, and mortality, and possibly vice versa. Multidisciplinary care pathways including lifestyle modifications, control of metabolic risk, and potentially beneficial treatments are important to improve the clinical outcomes of patients with NAFLD.

Non-obese or lean non-alcoholic fatty liver disease was associated with increased risk of cancer in patients with type 2 diabetes mellitus

INTRODUCTION

Risk of non-obese or lean non-alcoholic fatty liver disease (NAFLD) for cancer in patients with type 2 diabetes mellitus (T2DM) is less known. We aimed to evaluate independent associations of NAFLD, especially non-obese or lean NAFLD, and body mass index (BMI) on risks of cancer in patients with T2DM.

RESEARCH DESIGN AND METHODS

Cross-sectional analyses of baseline information on a cohort of 233 patients with T2DM were conducted in Xiamen, China. NAFLD was identified by hepatic ultrasonography diagnosis of hepatic steatosis without excessive alcohol consumption, viral or autoimmune liver disease. Fibrosis-4 (FIB-4) score was calculated to quantify severity of hepatic fibrosis.

RESULTS

All types of cancers were diagnosed on 19 (8.2%) patients. Prevalence of cancer was significantly higher in those with NAFLD than those without (15.5% vs 4.0%, p=0.002), but were not significantly different among BMI categories (6.8%, 13.7% and 6.5% for those with underweight or normal weight (n=74), overweight (n=51) and obesity (n=108), respectively, p=0.258). With adjustment for potential confounding factors in the multivariable logistic regression models, NAFLD was significantly associated with increased risk of cancer with the adjusted OR (95% CI) of 5.969 (1.349 to 26.413, p=0.019). Stratified analyses across BMI categories found similar association of NAFLD with risk of cancer for those non-obese or lean (the adjusted OR (95% CI) 17.446 (1.690 to 180.095, p=0.016)) but not for those with either overweight (OR (95% CI) 11.642 (0.832 to 162.963, p=0.068) or obesity (OR (95% CI) 0.917 (0.170 to 4.954, p=0.920). FIB-4 score was not significantly associated with risk of cancer for all subjects or stratified across BMI categories. BMI was not significantly associated with risk of cancer for all patients or stratified by NAFLD.

CONCLUSIONS

NAFLD, even non-obese or lean NAFLD, was independently associated with increased risk of cancer in patients with T2DM. Screening and management of NAFLD, especially for those with underweight or normal weight, should be strengthened from the perspective of improving prevention and management of cancer in patients with T2DM.

Risk factors in nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) is the most common liver disease, with a global prevalence estimated at approximately 25%. NAFLD is also the leading cause of liver cirrhosis, hepatocellular carcinoma, and death. Additionally, the risk of cardiovascular disease increases with greater NAFLD severity. The liver- and cardiovascular disease-related mortality incident rate ratios among the NAFLD population were 0.77 and 4.79 per 1,000 person-years, respectively. We intend to discuss the risk factors associated with NAFLD in terms of development and progression. Obesity or higher body mass index is closely associated with NAFLD in a dose-dependent manner, but growing evidence suggests that central obesity plays a more important role in the development of NAFLD. Saturated fat and fructose have been reported to be closely related to NAFLD. Fructose intake promotes lipogenesis and impairs mitochondria fat oxidation. The presence of type 2 diabetes is the most powerful predictive risk factor for hepatic fibrosis in patients with NAFLD. Single nucleotide polymorphism is not only associated with the prevalence of NAFLD but also associated with increased liver disease mortality. Obstructive sleep apnea, intestinal dysbiosis, and sarcopenia are associated with the development of NAFLD.

Nonalcoholic fatty liver disease and non-liver comorbidities

Non-alcoholic fatty liver disease (NAFLD) is a chronic liver disease characterized by excess fat accumulation in the liver. It is closely associated with metabolic syndrome, and patients with NAFLD often have comorbidities such as obesity, type 2 diabetes mellitus, and dyslipidemia. In addition to liver-related complications, NAFLD has been associated with a range of non-liver comorbidities, including cardiovascular disease, chronic kidney disease, and sleep apnea. Cardiovascular disease is the most common cause of mortality in patients with NAFLD, and patients with NAFLD have a higher risk of developing cardiovascular disease than the general population. Chronic kidney disease is also more common in patients with NAFLD, and the severity of NAFLD is associated with a higher risk of developing chronic kidney disease. Sleep apnea, a disorder characterized by breathing interruptions during sleep, is also more common in patients with NAFLD and is associated with the severity of NAFLD. The presence of non-liver comorbidities in patients with NAFLD has important implications for the management of this disease. Treatment of comorbidities such as obesity, type 2 diabetes mellitus, and dyslipidemia may improve liver-related outcomes in patients with NAFLD. Moreover, treatment of non-liver comorbidities may also improve overall health outcomes in patients with NAFLD. Therefore, clinicians should be aware of the potential for non-liver comorbidities in patients with NAFLD and should consider the management of these comorbidities as part of the overall management of this disease.

A Meta-analysis on Associated Risk of Mortality in Nonalcoholic Fatty Liver Disease

OBJECTIVE

Nonalcoholic fatty liver disease (NAFLD) affects much of the worldwide population and poses a significant burden to the global healthcare. The rising numbers of individuals with NAFLD and instances of mortality point toward the importance of understanding the association causes of mortality in NAFLD. This meta-analysis aimed to seek the associations of NAFLD with all-cause, cardiovascular disease (CVD)-related, liver-related, and cancer-related mortality.

METHODS

MEDLINE and Embase were searched for articles relating to causes of mortality between NAFLD and non-NAFLD. The DerSimonian and Laird random-effects model was used to analyze adjusted hazard ratios (HR), and a sensitivity analysis was conducted to reduce heterogeneity through a graphical display of study heterogeneity.

RESULTS

Fifteen studies involving 10 286 490 patients were included. Individuals with NAFLD exhibited an increased risk of all-cause mortality (HR, 1.32; 95% CI, 1.09-1.59; P < .01; I² = 96.00%), CVD-related mortality (HR, 1.22; 95% CI, 1.06-1.41; P < .01; I² = 81.00%), and cancer-related mortality (HR, 1.67; 95% CI, 1.15-2.41; P < .01; I² = 95.00%). However, no significant association was found between liver-related mortality and NAFLD (HR, 3.58; 95% CI, 0.69-18.46; P =.13; I² = 96.00%). The sensitivity analysis conducted with graphic display of heterogeneity and only population-based studies found similar results.

CONCLUSION

NAFLD was associated with an increased risk of all-cause, CVD-related, and cancer-related mortality but not liver-related mortality. The finding is likely because of low fibrosis prevalence in the community. However, the significant burden in other causes of mortality beyond the liver points to a need for multidisciplinary efforts to reduce the mortality risks.

The relationship between metabolic dysfunction-associated fatty liver disease and the incidence rate of extrahepatic cancer

BACKGROUND

The associations between metabolic dysfunction-associated fatty liver disease (MAFLD) and cancer development, especially extrahepatic cancers, are unknown. The aims of the current study were to investigate the cancer incidence rates of MAFLD and analyze the associations between MAFLD and the development of cancers.

METHODS

This historical cohort study included participants who underwent ultrasonographic detection of hepatic steatosis at a tertiary hospital in China from January 2013 to October 2021. MAFLD was diagnosed in accordance with The International Expert Consensus Statement. Cox proportional hazards regression modeling was used to assess the associations between MAFLD and the development of cancers.

RESULTS

Of the 47,801 participants, 16,093 (33.7%) had MAFLD. During the total follow-up of 175,137 person-years (median 3.3 years), the cancer incidence rate in the MAFLD group was higher than that in the non-MAFLD group [473.5 vs. 255.1 per 100,000 person-years; incidence rate ratio 1.86; 95% confidence interval (CI) 1.57-2.19]. After adjustment for age, gender, smoking status, and alcohol status, MAFLD was moderately associated with cancers of the female reproductive system/organs (labium, uterus, cervix, and ovary) [hazard ratio (HR) 2.24; 95% CI 1.09-4.60], thyroid (HR 3.64; 95% CI 1.82-7.30), and bladder (HR 4.19; 95% CI 1.15-15.27) in the total study cohort.

CONCLUSION

MAFLD was associated with the development of cancers of the female reproductive system/organs (labium, uterus, cervix, and ovary), thyroid, and bladder in the total study cohort.

MAFLD: a multisystem disease

Nonalcoholic fatty liver disease (NAFLD), affecting about 25% of general population and more than 50% of dysmetabolic patients, is an emerging cause of chronic liver disease and its complications. Recently, an international consensus of experts proposed to rename this disease as 'Metabolic dysfunction-Associated Fatty Liver Disease' (MAFLD) to focus on the bidirectional interplay between fatty liver and metabolic alterations and to stress the need of assessing fatty liver independently from alcohol consumption and other coexisting causes of liver disease. The peculiarity of NAFLD/MAFLD lies in the presence of a higher risk of not only - as expected - liver-related events but also of extrahepatic events, mostly cardiovascular and cancers. Available evidence suggests that these associations are not only the expression of sharing the same risk factors but shed light about the ability of NAFLD/MAFLD and particularly of its progressive form - nonalcoholic/metabolic dysfunction-associated steatohepatitis - to act as an independent risk factor via promotion of atherogenic dyslipidemia and a proinflammatory, profibrogenic, and procoagulant systemic environment. The present review summarizes available epidemiological and clinical evidence supporting the concept of NAFLD/MAFLD as a multisystemic disease, and highlights potential explanatory mechanisms underlying the association between NAFLD/MAFLD and extrahepatic disorders.

Lower serum PRL is associated with the development of non-alcoholic fatty liver disease: a retrospective cohort study

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) has become an epidemic worldwide and has been linked to a series of metabolic co-morbidities. Prolactin (PRL) has recently been found to have a negative effect on NAFLD, but a causal relationship is not well-understood. Here we investigated the causative relationship between PRL and NAFLD occurrence.

METHODS

In this retrospective cohort study, we enrolled patients without NAFLD who were diagnosed by abdominal ultrasonography undergone serum PRL testing at 8.00 a.m. at baseline, and followed up for a median of 32 (19, 46) months.

RESULTS

This study enrolled 355 persons [215 men and 140 women; media age 56 (49, 64) years], in which 72 (20.28%) patients who eventually developed NAFLD. Compared with those in the non-NAFLD group, basal serum PRL levels of patients were lower in the NAFLD group [male: 7.35 (5.48, 10.60) vs. 9.13 (6.92, 12.50) ug/L, P = 0.002; female: 5.66 (4.67, 9.03) vs. 9.01 (6.31, 11.60) ug/L, P = 0.009]. The prevalence of NAFLD was significantly decreased along with the increased quartile of basal serum PRL levels in both genders (P < 0.05). Serum PRL concentration was independently associated with NAFLD development [male: OR, 0.881 (0.777, 0.998), P = 0.047; female: OR, 0.725 (0.554, 0.949), P = 0.019].

CONCLUSION

Our study is the first to find that basal serum PRL level can predict the occurrence of NAFLD and it may be a potential biomarker to prevent and treat NAFLD.

The role of noninvasive scoring systems for predicting cardiovascular disease risk in patients with nonalcoholic fatty liver disease: a systematic review and meta-analysis

BACKGROUNDS

Cardiovascular disease (CVD) is suggested as a leading cause of death among patients with nonalcoholic fatty liver disease (NAFLD). The aim of this work was to clarify the role of noninvasive scoring systems (NSSs) in predicting CVD risk among this population.

METHODS

The PubMed, Web of Science, and Cochrane databases were searched until 23 March 2022. Meta-analysis was performed for three most commonly used NSS separately, that is, fibrosis-4 index (FIB-4), NAFLD fibrosis score (NFS), and AST/platelet ratio index (APRI).

RESULTS

Totally, nine studies including 155 382 patients with NAFLD were enrolled. Patients with NAFLD had a higher risk of CVD with increasing FIB-4 score (1.94, 1.52-2.46), the association remained significant after adjustment for age, sex, body mass index, hypertension, and diabetes (2.44, 1.85-3.22). Similarly, a higher risk of CVD was also observed in patients with increasing NFS (2.17, 1.58-2.98) and APRI scores (1.36, 1.04-1.79) in the unadjusted model. However, in the adjusted model, the association was significant only for NFS (3.83, 1.40-10.43), but not for APRI (1.41, 0.79-2.51). Additionally, the increment in CVD risk was most noticeable in subgroup of FIB &gt; 2.67 vs. FIB ≤ 1.3 (6.52, 3.07-13.86) and subgroup of NFS &gt; 0.676 vs. NFS ≤ -1.455 (16.88, 5.68-50.23). All subgroup analyses showed significant associations between FIB-4, NFS, and risk of CVD. Sensitivity analyses did not modify these results.

CONCLUSIONS

FIB-4 and NFS might be useful in identifying those who are at higher risk of CVD among patients with NAFLD. However, APRI was not recommended for this use.

Metabolic mechanisms for and treatment of NAFLD or NASH occurring after liver transplantation

The rising tide of non-alcoholic fatty liver disease (NAFLD) associated with the obesity epidemic is a major health concern worldwide. NAFLD - specifically its more advanced form, non-alcoholic steatohepatitis (NASH)-related cirrhosis - is now the fastest growing indication for liver transplantation in the USA and Europe. Although the short-term and mid-term overall survival rates of patients who receive a liver transplant for NASH-related cirrhosis are essentially similar to those of patients who receive a transplant for other liver indications, recipients with NASH-related cirrhosis have an increased risk of waiting-list mortality and of developing recurrent liver disease and cardiometabolic complications in the longer term after liver transplantation. This Review provides a brief overview of the epidemiology of NAFLD and NASH and the occurrence of NAFLD or NASH in patients after liver transplantation for NASH and other liver indications. It also discusses the putative metabolic mechanisms underlying the emergence of NAFLD or NASH after liver transplantation as well as optimal therapeutic approaches for recipients of liver transplants, including the management of cardiometabolic comorbidities, tailored immunosuppression, lifestyle changes and pharmacotherapy for NAFLD.

Dissecting causal relationships between nonalcoholic fatty liver disease proxied by chronically elevated alanine transaminase levels and 34 extrahepatic diseases

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) is prevalent worldwide and is associated with the risk of many extrahepatic diseases. However, whether NAFLD is a risk marker or a common cause of extrahepatic diseases is unclear.

METHODS

We searched PubMed to identify NAFLD-related extrahepatic diseases. Genetic instrumental variables (IVs) for NAFLD surrogated by chronically elevated alanine transaminase levels and eligible extrahepatic diseases were retrieved from the corresponding genome-wide association analysis. We proposed a procedure for Mendelian randomization (MR) analysis and performed validation analyses to dissect the association between NAFLD and extrahepatic diseases. The Bonferroni method was used to correct the bias of multiple testing.

RESULTS

In total, 34 extrahepatic diseases were included and 54 SNPs were used as IVs for NAFLD. The MR analysis gave a robust and significant (or suggestive) estimate for the association between NAFLD and 9 extrahepatic diseases: type 2 diabetes (odds ratio [OR] = 1.182, 95 % confidence interval [CI] 1.125-1.243, P = 5.40 × 10^-11), cholelithiasis (OR = 1.171, 95%CI 1.083-1.266, P = 7.47 × 10^-5), diabetic hypoglycemia (OR = 1.170, 95%CI 1.071-1.279, P = 5.14 × 10^-4), myocardial infarction (OR = 1.122, 95%CI 1.057-1.190, P = 1.46 × 10^-4), hypertension (OR = 1.060, 95%CI 1.029-1.093, P = 1.18 × 10^-4), coronary artery disease (OR = 1.052, 95%CI 1.010-1.097, P = 1.58 × 10^-2), heart failure (OR = 1.047, 95%CI 1.006-1.090, P = 2.44 × 10^-2), dementia (OR = 0.881, 95%CI 0.806-0.962, P = 5.01 × 10^-3), and pancreatic cancer (OR = 0.802, 95%CI 0.654-0.983, P = 3.32 × 10^-2). Validation analyses using IVs from biopsy-confirmed and imaging-determined NAFLD reported similar results to the main analysis. For the remaining 25 outcomes, no significant or definitive association was yielded in MR analysis.

CONCLUSIONS

Genetic evidence suggests putative causal relationships between NAFLD and a set of extrahepatic diseases, indicating that NAFLD deserves high priority in clinical practice.

Non-alcoholic fatty liver disease and risk of new-onset heart failure: an updated meta-analysis of about 11 million individuals

OBJECTIVE

Recent studies reported an association between non-alcoholic fatty liver disease (NAFLD) and increased risk of new-onset heart failure (HF). However, the magnitude of the risk and whether this risk changes with severity of liver disease remains uncertain. We performed a meta-analysis of observational studies to quantify the magnitude of the association between NAFLD and risk of new-onset HF.

DESIGN

We systematically searched Scopus, Web of Science and PubMed from database inception to March 2022 to identify eligible observational studies, in which NAFLD was diagnosed by serum biomarkers/scores, International Classification of Diseases (ICD) codes, imaging techniques or liver histology. The primary outcome was new-onset HF, as assessed mainly by ICD codes. Data from selected studies were extracted, and meta-analysis was performed using random-effects models to obtain summary hazard ratios (HRs) with 95% CIs.

RESULTS

We identified 11 longitudinal cohort studies with aggregate data on 11 242 231 middle-aged individuals from different countries and 97 716 cases of incident HF over a median of 10 years. NAFLD was associated with a moderately higher risk of new-onset HF (pooled random-effects hazard ratio 1.50, 95% CI 1.34 to 1.67, p<0.0001; I 2=94.8%). This risk was independent of age, sex, ethnicity, adiposity measures, diabetes, hypertension and other common cardiovascular risk factors. Sensitivity analyses did not change these results. The funnel plot did not show any significant publication bias.

CONCLUSION

NAFLD is associated with a 1.5-fold higher long-term risk of new-onset HF, regardless of the presence of diabetes, hypertension and other common cardiovascular risk factors. However, the observational design of the studies does not allow for proving causality.

AGILE 3+ Score for the Diagnosis of Advanced Fibrosis and for Predicting Liver-related Events in NAFLD

BACKGROUND & AIMS

We aimed to assess the diagnostic accuracy of AGILE 3+, a recently developed score based on the combination of aspartate aminotransferase/alanine aminotransferase ratio, platelet count, diabetes status, sex, age, and liver stiffness measurement (LSM) by transient elastography, when compared with Fibrosis-4 (FIB-4) and LSM, for the diagnosis of advanced fibrosis and for the prediction of liver-related events (LREs) occurrence in patients with NAFLD.

METHODS

A total of 614 consecutive patients with biopsy-proven NAFLD or clinical diagnosis of NAFLD-related compensated cirrhosis were enrolled. LREs were recorded during follow-up. FIB-4, LSM by transient elastography (FibroScan device), and AGILE 3+ were measured. The diagnostic performance of noninvasive criteria for advanced fibrosis and for the prediction of LREs was assessed using the area under the receiver operating characteristic curve (AUROC) and decision curve analysis.

RESULTS

In patients with biopsy-proven NAFLD (n = 520), LSM and AGILE 3+ had higher AUROC than FIB-4 (0.88 for LSM and AGILE 3+ vs 0.78 for FIB-4; P < .001) for advanced fibrosis, and AGILE 3+ exhibited a smaller indeterminate area in the test (25.2% for FIB-4 vs 13.1% for LSM vs 8.3% for AGILE 3+). Within the entire cohort of patients, AGILE 3+ had significantly higher AUROC for predicting LREs with respect to LSM (AUROC 36 months 0.95 vs 0.93; P =.008; 60 months 0.95 vs 0.92; P = .006; 96 months 0.97 vs 0.95; P = .001). Decision curve analysis showed that all scores had modest net benefit for ruling-out advanced fibrosis at the risk threshold of 5% to 10% where advanced fibrosis was absent. At the risk threshold of 5% of false negatives or false positives in LRE at 36, 60, 96, and 120 months, AGILE 3+ outperformed both FIB-4 and LSM for ruling out LRE.

CONCLUSIONS

Depending on resource availability, clinical setting, and the risk scenarios, AGILE 3+ is an accurate and valid alternative to FIB-4 and LSM for the noninvasive assessment of disease severity and prognosis in patients with NAFLD.

Nonalcoholic Fatty Liver Disease and Cardiovascular Disease: a Review of Shared Cardiometabolic Risk Factors

The prevalence of nonalcoholic fatty liver disease (NAFLD) is rising. NAFLD/nonalcoholic steatohepatitis (NASH) is associated not only with hepatic morbidity and mortality but also with an increased cardiovascular risk. NAFLD and cardiovascular disease (CVD) share several risk factors, such as obesity, metabolic syndrome, hypertension, dyslipidemia, type 2 diabetes, and chronic kidney disease. This review summarizes the evidence linking cardiometabolic risk factors and NAFLD in the context of risk for CVD. The cause of NAFLD/NASH is complex, involving a range of factors from genetics to lifestyle and energy balance. Genetically driven high liver fat content does not appear to be causally associated with increased CVD risk. In contrast, metabolic dysfunction not only predisposes to liver pathology but also leads to a significantly higher CVD risk. Given that NAFLD pathophysiology is influenced by multiple factors, each patient is unique as to their risk of developing CVD and liver pathology. At the same time, the rising burden of NAFLD/NASH is closely linked with the global increase in metabolic disorders, including obesity and type 2 diabetes. Therefore, both personalized therapeutic approaches that recognize individual pathophysiology, as well as public health policies that address the root causes of cardiometabolic risk factors for NAFLD may be needed to effectively address the NAFLD/NASH epidemic.

Risk of non-alcoholic fatty liver disease in patients with chronic plaque psoriasis: an updated systematic review and meta-analysis of observational studies

PURPOSE

Chronic plaque psoriasis is associated with the presence of non-alcoholic fatty liver disease (NAFLD), but the magnitude of this association remains currently uncertain. We aimed to investigate the magnitude of the association between psoriasis and the risk of prevalent and incident NAFLD, and to assess whether psoriasis severity and/or psoriatic arthritis are associated with a greater risk of NAFLD.

METHODS

A systematic review and meta-analysis of observational studies evaluating the association between psoriasis and NAFLD, as diagnosed by imaging or International Classification of Diseases codes was performed. Literature search on PubMed, Scopus and Web of Science on May 3, 2021 was undertaken. Studies using liver biopsy were not available. For the meta-analysis, the random-effects modelling was adopted.

RESULTS

We identified 15 observational (case-control and cross-sectional) studies for a total of 249,933 patients with psoriasis (49% with NAFLD) and 1,491,402 controls (36% with NAFLD). Psoriasis was associated with prevalent NAFLD (n = 11 studies; pooled random-effects odds ratio [OR] 1.96, 95% CI 1.70-2.26; I² = 97%, p < 0.01). Psoriatic patients with NAFLD had a higher mean psoriasis area and severity index (PASI) than their counterparts without NAFLD (n = 8 studies, pooled weighted mean difference: 3.93, 95% CI 2.01-5.84; I² = 88%, p < 0.01). The risk of NAFLD was marginally higher in patients with psoriatic arthritis than in those with psoriasis alone (n = 5 studies, pooled random-effects OR 1.83, 95% CI 0.98-3.43; I² = 64%, p = 0.03). Sensitivity analyses did not alter these findings. Funnel plot did not show any significant publication bias. A major limitation of the study was the high degree of heterogeneity across studies.

CONCLUSION

Psoriasis is associated with prevalent NAFLD and this risk parallels the severity of psoriasis.

The role of microbiota in nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) is the most frequent liver disease worldwide. Gut microbiota can play a role in the pathogenesis of NAFLD since dysbiosis is associated with reduced bacterial diversity, altered Firmicutes/Bacteroidetes ratio, a relative abundance of alcohol-producing bacteria, or other specific genera. Changes can promote disrupted intestinal barrier and hyperpermeability, filtration of bacterial products, activation of the immune system, and pro-inflammatory changes in the intestine, in the liver, and at a systemic level. Microbiota-derived molecules can contribute to the steatogenic effects. The link between gut dysbiosis and NAFLD, however, is confused by several factors which include age, BMI, comorbidities, dietary components, and lifestyle. The role of toxic chemicals in food and water requires further studies in both gut dysbiosis and NAFLD. We can anticipate that gut microbiota manipulation will represent a potential therapeutic tool to delay or reverse the progression of NAFLD, paving the way to primary prevention measures.

Current therapies and new developments in NASH

Non-alcoholic steatohepatitis is becoming the most important aetiology for advanced liver disease. There has been important progress in the field in recent years and the complexity of the pathophysiology of NASH is better understood. Multiple non-invasive circulating and imaging biomarkers have been tested. The importance of lifestyle has been recognised and several drugs are being tested in clinical trials. This review addresses the challenges that healthcare professionals face in the management of NASH patients.

Bile acids and sphingolipids in non-alcoholic fatty liver disease

ABSTRACT

Non-alcoholic fatty liver disease (NAFLD) is one of the fastest-growing diseases, and its global prevalence is estimated to increase >50% by 2030. NAFLD is comorbid with metabolic syndrome, obesity, type 2 diabetes, and insulin resistance. Despite extensive research efforts, there are no pharmacologic or biological therapeutics for the treatment of NAFLD. Bile acids and sphingolipids are well-characterized signaling molecules. Over the last few decades, researchers have uncovered potential mechanisms by which bile acids and sphingolipids regulate hepatic lipid metabolism. Dysregulation of bile acid and sphingolipid metabolism has been linked to steatosis, inflammation, and fibrosis in patients with NAFLD. This clinical observation has been recapitulated in animal models, which are well-accepted by experts in the hepatology field. Recent transcriptomic and lipidomic studies also show that sphingolipids are important players in the pathogenesis of NAFLD. Moreover, the identification of bile acids as activators of sphingolipid-mediated signaling pathways established a novel theory for bile acid and sphingolipid biology. In this review, we summarize the recent advances in the understanding of bile acid and sphingolipid-mediated signaling pathways as potential contributors to NAFLD. A better understanding of the pathologic effects mediated by bile acids and sphingolipids will facilitate the development of new diagnostic and therapeutic strategies for NAFLD.

Nonalcoholic fatty liver disease and health outcomes: An umbrella review of systematic reviews and meta-analyses

Purpose:

A large number of systemic reviews and meta-analyses have explored the relationship between nonalcoholic fatty liver disease (NAFLD) and multiple health outcomes. The aim of this study is to conduct an umbrella review to assess the strength and evidence for the association between NAFLD and health outcomes.

Methods:

We systematically identified the present meta-analyses of observational studies reporting an association between NAFLD and health outcomes. For each meta-analysis, we assessed the quality with AMSTAR2 and graded the epidemiologic evidence.

Results:

Fifty-four articles comprising 111 unique meta-analyses were included in this study. Eighty-five unique outcomes showed significant associations ( P ← 0.05), whereas 26 unique outcomes showed insignificant associations, and we cannot assess the epidemiologic evidence. For 85 significant health outcomes, four outcomes (carotid intima-media thickness (C-IMT), peak A velocity, left ventricle end-diastolic diameter, incident chronic kidney disease (CKD) in adult patients) was graded as high quality of evidence, 23 outcomes were graded as the moderate quality of evidence, and the remaining 58 outcomes were graded as weak quality of evidence. Fourty-seven (87.03%) studies showed critically low methodological quality.

Conclusion:

In this umbrella review, only four statistically significant health outcomes showed high epidemiologic evidence. NAFLD seems to relate to an increased risk of C-IMT, peak A velocity, left ventricle end-diastolic diameter, and incident CKD in adult patients.

Histological assessment based on liver biopsy: the value and challenges in NASH drug development

Nonalcoholic steatohepatitis (NASH) is increasingly recognized as a serious disease that can lead to cirrhosis, hepatocellular carcinoma (HCC), and death. However, there is no effective drug to thwart the progression of the disease. Development of new drugs for NASH is an urgent clinical need. Liver biopsy plays a key role in the development of new NASH drugs. Histological findings based on liver biopsy are currently used as the main inclusion criteria and the primary therapeutic endpoint in NASH clinical trials. However, there are inherent challenges in the use of liver biopsy in clinical trials, such as evaluation reliability, sampling error, and invasive nature of the procedure. In this article, we review the advantages and value of liver histopathology based on liver biopsy in clinical trials of new NASH drugs. We also discuss the challenges and limitations of liver biopsy and identify future drug development directions.

Interaction of SAMM50-rs738491, PARVB-rs5764455 and PNPLA3-rs738409 Increases Susceptibility to Nonalcoholic Steatohepatitis

BACKGROUND AND AIMS

Previous studies have reported that the single nucleotide polymorphisms (SNPs) of SAMM50-rs738491, PARVB-rs5764455 and PNPLA3-rs738409 are associated with nonalcoholic fatty liver disease (NAFLD). However, no studies have examined the effect of interactions between these three genotypes to affect liver disease severity. We assessed the effect of these three SNPs on nonalcoholic steatohepatitis (NASH) and also examined the gene-gene interactions in a Chinese population with biopsy-confirmed NAFLD.

METHODS

We enrolled 415 consecutive adult individuals with biopsy-proven NAFLD. Multivariable logistic regression analysis was undertaken to test associations between NASH and SNPs in SAMM50-rs738491, PARVB-rs5764455 and PNPLA3-rs738409. Gene-gene interactions were analyzed by performing a generalized multifactor dimensionality reduction (GMDR) analysis.

RESULTS

The mean ± standard deviation age of these 415 patients was 41.3±12.5 years, and 75.9% were men. Patients with SAMM50-rs738491 TT, PARVB-rs5764455 AA or PNPLA3-rs738409 GG genotypes had a higher risk of NASH, even after adjustment for age, sex and body mass index. GMDR analysis showed that the combination of all three SNPs was the best model for predicting NASH. Additionally, the odds ratio of the haplotype T-A-G for predicting the risk of NASH was nearly three times higher than that of the haplotype G-C-C.

CONCLUSIONS

NAFLD patients carrying the SAMM50-rs738491 TT, PARVB-rs5764455 AA or PNPLA3-rs738409 GG genotypes are at greater risk of NASH. These three SNPs may synergistically interact to increase susceptibility to NASH.

MAFLD: what 2 years of the redefinition of fatty liver disease has taught us

Metabolic dysfunction-associated fatty liver disease (MAFLD) has appeared as the leading liver disease worldwide. Whereas the terminology nonalcoholic fatty liver disease (NAFLD) mainly reflected a negative selection and exclusion of alcohol-related liver disease (ALD), the new definition made its focus on the association of MAFLD with overweight/obesity, type 2 diabetes and metabolic risk factors especially also in normal weight/lean subjects. Several studies from the past 2 years have now used the new definition and have provided substantial information that this new definition might be accurate. Studies from the past 2 years have provided evidence that the new definition might be especially advantageous in the characterization and identification of patients with significant fibrosis. This has also been demonstrated in the well-known Rotterdam study in which the MAFLD-only group showed a higher rate of fibrosis and liver stiffness. MAFLD might also be able to predict all-cause mortality as demonstrated in the Third National Health and Nutrition Examination Survey. Furthermore, MAFLD might improve characterization of the cardiovascular risk of this patient population. As the term MAFLD has not yet been accepted universally, it remains important to coordinate efforts globally to adapt to this new definition and especially involve all specialities dealing with metabolic disorders such as diabetologists to further improve its definition and to prepare the medical community for its future use. The aim of this review is to summarize and critically address evidence emerging over the past 2 years that usage of the term MAFLD could be helpful in daily clinical practice.

Epidemiology and Clinical Outcomes of Metabolic (Dysfunction)-associated Fatty Liver Disease

Metabolic (dysfunction)-associated fatty liver disease (MAFLD) is currently the most common chronic liver disease and affects at least a quarter of the global adult population. It has rapidly become one of the leading causes of hepatocellular carcinoma and cirrhosis in Western countries. In this review, we discuss the nomenclature and definition of MAFLD as well as its prevalence and incidence in different geographical regions. Although cardiovascular disease remains the leading cause of death in MAFLD patients, the proportion of patients dying from hepatic complications increases sharply as the disease progresses to advanced liver fibrosis and cirrhosis. In addition, patients with MAFLD are at increased risk of various extrahepatic cancers. Although a causal relationship between MAFLD and extrahepatic cancers has not been established, clinicians should recognize the association and consider cancer screening (e.g., for colorectal cancer) as appropriate.

Non-alcoholic fatty liver disease: A patient guideline

This patient guideline is intended for all patients at risk of or living with non-alcoholic fatty liver disease (NAFLD). NAFLD is the most frequent chronic liver disease worldwide and comes with a high disease burden. Yet, there is a lot of unawareness. Furthermore, many aspects of the disease are still to be unravelled, which has an important impact on the information that is given (or not) to patients. Its management requires a close interaction between patients and their many healthcare providers. It is important for patients to develop a full understanding of NAFLD in order to enable them to take an active role in their disease management. This guide summarises the current knowledge relevant to NAFLD and its management. It has been developed by patients, patient representatives, clinicians and scientists and is based on current scientific recommendations, intended to support patients in making informed decisions.

Fatty liver disease and changes in dense breasts in pre- and postmenopausal women: the Kangbuk Samsung Health Study

PURPOSE

While increased breast density is a risk factor for breast cancer, the effect of fatty liver disease on breast density is unknown. We investigated whether fatty liver is a risk factor for changes in breast density over ~ 4 years of follow-up in pre- and postmenopausal women.

METHODS

This study included 74,781 middle-aged Korean women with mammographically determined dense breasts at baseline. Changes in dense breasts were identified by more screening mammograms during follow-up. Hepatic steatosis (HS) was measured using ultrasonography. Flexible parametric proportional hazards models were used to determine the adjusted hazard ratios (aHRs) and 95% confidence intervals (CIs), and a Weibull accelerated failure time model (AFT) was used to determine the time ratios (TRs) and 95% CIs.

RESULTS

During a median follow-up of 4.1 years, 4022 women experienced resolution of the dense breasts. The association between HS and dense breast resolution differed by the menopause status (P for interaction < 0.001). After adjusting for body mass index and other covariates, the aHRs (95% CI) for dense breast resolution comparing HS to non-HS were 0.81 (0.70-0.93) in postmenopausal women, while the association was converse in premenopausal women with the corresponding HRs of 1.30 (1.18-1.43). As an alternative approach, the multivariable-adjusted TR (95% CI) for dense breast survival comparing HS to non-HS were 0.81 (0.75-0.87) and 1.19 (1.06-1.33) in premenopausal and postmenopausal women, respectively.

CONCLUSION

The association between HS and changes in dense breasts differed with the menopause status. HS increased persistent dense breast survival in postmenopausal women but decreased it in premenopausal women.

Intestinal dysbiosis in nonalcoholic fatty liver disease (NAFLD): focusing on the gut-liver axis

Nonalcoholic fatty liver disease (NAFLD) is one of the most common chronic liver disorders in humans, partly because it is closely related to metabolic disorders of the liver with increasing prevalence. NAFLD begins with hepatic lipid accumulation, which may cause inflammation and eventually lead to fibrosis in the liver. Numerous studies have demonstrated the close relationship between gut dysfunction (especially the gut microbiota and its metabolites) and the occurrence and progression of NAFLD. The bidirectional communication between the gut and liver, named the gut-liver axis, is mainly mediated by the metabolites derived from both the liver and gut through the biliary tract, portal vein, and systemic circulation. Herein, we review the effects of the gut-liver axis on the pathogenesis of NAFLD. We also comprehensively describe the potential molecular mechanisms from the perspective of the role of liver-derived metabolites and gut-related components in hepatic metabolism and inflammation and gut health, respectively. The study provides insights into the mechanisms underlying current summarizations that support the intricate interactions between a disordered gut and NAFLD and can provide novel strategies to lessen the prevalence and consequence of NAFLD.

The Troubling Link Between Non-alcoholic Fatty Liver Disease (NAFLD) and Extrahepatic Cancers (EHC)

Non-alcoholic fatty liver disease (NAFLD) is a fast-spreading epidemic across the globe and has serious implications far beyond that of a "benign" liver condition. It is usually an outcome of ectopic fat storage due to chronic positive energy balance leading to obesity and is associated with multiple health problems. While association with cardiovascular disease and hepatocellular cancer is well recognized, it is becoming clear the NAFLD carries with it an increased risk of cancers of extrahepatic tissues. Studies have reported a higher risk for cancers of the colon, breast, prostate, lung, and pancreas. Fatty liver is associated with increased mortality; there is an urgent need to understand that fatty liver is not always benign, and not always associated with obesity. It is, however, a reversible condition and early recognition and intervention can alter its natural history and associated complications.

Non-alcoholic fatty liver disease is associated with increased risk of chronic kidney disease

Background and Aims

Whether non-alcoholic fatty liver disease (NAFLD) is associated with an increased risk of incident chronic kidney disease (CKD) independent of established cardio-renal risk factors remains controversial. We aimed to provide a quantitative estimate of the association and strength between NAFLD and risk of CKD after adjustment for multiple cardio-renal risk factors.

Methods

We searched electronic databases (PubMed, Embase, and Google Scholar) for studies published from database inception until 30 November 2020. Analysis included cohort studies that reported multivariable-adjusted risk ratios [including odds ratios, relative risks (RRs), or hazard ratios] and 95% confidence intervals (CIs) for CKD of NAFLD compared with individuals without NAFLD.

Results

A total of 11 cohort studies were included comprising 1,198,242 participants (46.3% women) for analysis. The median follow-up duration was 3.7 years, with 31,922 cases of incident CKD. Compared with individuals without NAFLD, unadjusted models showed that NAFLD was associated with a higher risk of CKD (RR 1.54, 95% CI 1.38-1.71). After adjusting for multiple cardio-renal risk factors, the CKD risk was still significantly increased in patients with NAFLD (RR 1.39, 95% CI 1.27-1.52). Compared with individuals without NAFLD, the adjusted absolute risk increase in NAFLD for CKD was 5.1 (95% CI 3.5-6.8) per 1000 person-years.

Conclusion

NAFLD is associated with an increased risk of incident CKD independent of established cardio-renal risk factors.