Alcohol consumption and risk of fatty liver disease: a meta-analysis

Multi-system diseases and death trajectory of metabolic dysfunction-associated fatty liver disease: findings from the UK Biobank

BACKGROUND

Metabolic dysfunction-associated fatty liver disease (MAFLD) is a newly defined condition encompassing hepatic steatosis and metabolic dysfunction. However, the relationship between MAFLD and multi-system diseases remains unclear, and the time-dependent sequence of these diseases requires further clarification.

METHODS

After propensity score matching, 163,303 MAFLD subjects and 163,303 matched subjects were included in the community-based UK Biobank study. The International Classification of Diseases, Tenth Revision (ICD-10), was used to reclassify medical conditions into 490 and 16 specific causes of death. We conducted a disease trajectory analysis to map the key pathways linking MAFLD to various health conditions, providing an overview of their interconnections.

RESULTS

Participants aged 59 (51-64) years, predominantly males (62.5%), were included in the study. During the 12.9-year follow-up period, MAFLD participants were found to have a higher risk of 113 medical conditions and eight causes of death, determined through phenome-wide association analysis using Cox regression models. Temporal disease trajectories of MAFLD were established using disease pairing, revealing intermediary diseases such as asthma, diabetes, hypertension, hypothyroid conditions, tobacco abuse, diverticulosis, chronic ischemic heart disease, obesity, benign tumors, and inflammatory arthritis. These trajectories primarily resulted in acute myocardial infarction, disorders of fluid, electrolyte, and acid-base balance, infectious gastroenteritis and colitis, and functional intestinal disorders. Regarding death trajectories of MAFLD, malignant neoplasms, cardiovascular diseases, and respiratory system deaths were the main causes, and organ failure, infective disease, and internal environment disorder were the primary end-stage conditions. Disease trajectory analysis based on the level of genetic susceptibility to MAFLD yielded consistent results.

CONCLUSIONS

Individuals with MAFLD have a risk of a number of different medical conditions and causes of death. Notably, these diseases and potential causes of death constitute many pathways that may be promising targets for preventing general health decline in patients with MAFLD.

The effects of moderate alcohol consumption on non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is accepted as a counterpart to alcohol-related liver disease because it is defined as hepatic steatosis without excessive use of alcohol. However, the definition of moderate alcohol consumption, as well as whether moderate alcohol consumption is beneficial or detrimental, remains controversial. In this review, the findings of clinical studies to date with high-quality evidence regarding the effects of moderate alcohol consumption in NAFLD patients were compared and summarized.

Risk for hepatic and extra-hepatic outcomes in nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) is defined by presence of steatosis in more than 5% of liver cells. The gold standard for diagnosis is liver biopsy, but this is seldom achieved due to costs and risk for side effects, and that is why the diagnosis is mostly made based on a combination of radiology and exclusion of other liver diseases. Disease severity staging can be noninvasively achieved with radiological exams such as elastography or blood-based markers that usually have lower sensitivity and specificity. NAFLD is today the most common chronic liver disease globally with a prevalence estimated to be 25%. Fortunately, for many persons NAFLD is an incidental finding with a good prognosis. Whilst a major focus has been on liver-related outcomes in NAFLD, there has recently been an increased interest in extrahepatic consequences of NAFLD. The most commonly studied outcomes include cardiovascular disease and cancer. The risk of adverse outcomes generally differs according to the baseline fibrosis stage. There is a five-time higher risk of liver-related events in NAFLD patients with fibrosis stage 3 as compared to those with no or little fibrosis. Meanwhile, the presence of nonalcoholic steatohepatitis (NASH) does not seem to influence prognosis in addition to fibrosis stage. Patients with NAFLD clearly have a higher risk for cardiovascular outcomes compared to the general population, with a recent meta-analysis indicating a 37% increased hazard for cardiovascular events as opposed to individuals without NAFLD. The risk of liver cancer is increased, which is mostly driven by presence of cirrhosis, but the increased risk is present also in patients without cirrhosis, and to a greater extent than for other chronic liver disease. Around one-third of patients with NAFLD and liver cancer do not have cirrhosis. Additionally, the risk of extrahepatic malignancies is thought to be moderately increased, with most evidence for a link between NAFLD and colorectal cancer where the risk is approximately 50% higher compared to patients without NAFLD. A particularly salient point is if NAFLD can be considered an independent risk factor for outcomes. Many studies have not been able to adjust for key confounders, or suffer from different forms of bias. The clinical problem is nevertheless to identify persons with an increased risk for adverse hepatic and extrahepatic outcomes. We here discuss the evidence linking NAFLD to severe hepatic and extrahepatic outcomes.

Alcohol and Metabolic-associated Fatty Liver Disease

The diagnosis of metabolic-associated fatty liver disease is based on the detection of liver steatosis together with the presence of metabolic dysfunction. According to this new definition, the diagnosis of metabolic-associated fatty liver disease is independent of the amount of alcohol consumed. Actually, alcohol and its metabolites have various effects on metabolic-associated abnormalities during the process of alcohol metabolism. Studies have shown improved metabolic function in light to moderate alcohol drinkers. There are several studies focusing on the role of light to moderate alcohol intake on metabolic dysfunction. However, the results from studies are diverse, and the conclusions are often controversial. This review systematically discusses the effects of alcohol consumption, focusing on light to moderate alcohol consumption, obesity, lipid and glucose metabolism, and blood pressure.

Alcohol drinking and risks of liver cancer and non-neoplastic chronic liver diseases in China: a 10-year prospective study of 0.5 million adults

BACKGROUND

Alcohol consumption is an important risk factor for hepatic neoplastic and non-neoplastic diseases. Questions remain, however, about the relevance to disease risk of drinking patterns and alcohol tolerability, which differ appreciably between Chinese and Western populations.

METHODS

The prospective China Kadoorie Biobank included 512,715 adults (41% men) aged 30-79 years recruited from ten areas during 2004-2008, recording alcohol intake, drinking patterns, and other characteristics. After median 10 years' follow-up, 2531 incident liver cancer, 2040 liver cirrhosis, 260 alcoholic liver disease (ALD), and 1262 non-alcoholic fatty liver disease (NAFLD) cases were recorded among 492,643 participants without prior cancer or chronic liver disease at baseline. Cox regression was used to estimate adjusted hazard ratios (HR) relating alcohol intake and drinking patterns to each disease.

RESULTS

Overall, 33% of men and 2% of women drank alcohol regularly (i.e. at least weekly) at baseline. Among male current regular drinkers, alcohol consumption showed positive dose-response associations with risks of several major chronic liver diseases, with HRs per 280 g/week (i.e. around four drinks/day) higher usual alcohol intake of 1.44 (95% CI 1.23-1.69) for liver cancer (n = 547), 1.83 (1.60-2.09) for liver cirrhosis (n = 388), 2.01 (1.77-2.28) for ALD (n = 200), 1.71 (1.35-2.16) for NAFLD (n = 198), and 1.52 (1.40-1.64) for total liver disease (n = 1775). The association with ALD appeared stronger among men reporting flushing (i.e., with low alcohol tolerance). After adjustment for the total amount of weekly alcohol consumption, daily drinkers had significantly increased risk of ALD (2.15, 1.40-3.31) compared with non-daily drinkers, and drinking without meals was associated with significantly greater risks of liver cancer (1.32, 1.01-1.72), liver cirrhosis (1.37, 1.02-1.85), and ALD (1.60, 1.09-2.33) compared with drinking with meals. Female current regular drinkers had significantly higher risk of ALD, but not other liver diseases, than female abstainers.

CONCLUSIONS

In Chinese men, alcohol intake was associated with significantly increased risks of several major chronic liver diseases, and certain drinking patterns (e.g. drinking daily, drinking without meals) may further exacerbate the disease risks.

Causes of Death and Survival in Alcoholic Cirrhosis Patients Undergoing Liver Transplantation: Influence of the Patient's Clinical Variables and Transplant Outcome Complications

Background. Clinical and molecular mechanisms involved in the cause and time of death of alcoholic cirrhosis (AC) patients undergoing liver transplantation (LT) are not entirely understood. In sudden death cases, judicial autopsy practice is mandatory for determining the cause and circumstances of death. The medico-legal autopsy data are essential for helping health authorities to guide future public health activities, assess the effectiveness of health systems, and adopt the necessary preventive measures to improve and adapt the treatments in order to increase these patients’ survival. Objective. Our study aimed to determine the different clinical and sociodemographic causes that influence the different causes of death and the short- and long-term survival of AC patients undergoing liver transplantation. Methods. A total of 122 deceased AC patients undergoing LT were analyzed at different times post-transplantation. The main pre- and post-transplant complications were analyzed in relation to the cause of death and the patient’s survival, as well as the causes and time at which the patient’s death occurred. Results. A total of 53.3% of non-sudden death was observed. A large number of the deaths of AC patients undergoing transplantation were due to non-sudden death, sepsis, and graft failure (GF), the main causes of death in the sample being similar in both sexes. In non-sudden deaths, there were no significant differences between the death rates either related or not related to the liver transplant. Sepsis was the main cause, with the highest percentage (21.3%) of mortality, followed by GF (18.9%) and multiorgan failure (15.6%) at ten years. Furthermore, our results showed how pre-transplant clinical complications, such as viral infections and encephalopathy, influence the age at which multiorgan failure occurs in the transplanted patient. Conclusion. Multiorgan failure is the leading cause of sudden death, with higher mortality during the first year after transplantation, followed by sepsis and GF. Our results show the vulnerability of AC patients, both in the hospital period after the transplant and outside.

A single-letter change in an acronym: signals, reasons, promises, challenges, and steps ahead for moving from NAFLD to MAFLD

Introduction: We are currently at the dawn of a revolution in the field of fatty liver diseases. Recently, a consensus recommended 'metabolic (dysfunction) associated fatty liver disease' (MAFLD) as a more appropriate name to describe fatty liver disease associated with metabolic dysfunction, ultimately suggesting that the old acronym nonalcoholic fatty liver disease (NAFLD) should be abandoned.Areas covered: In this viewpoint, we discuss the reasons and relevance of this semantic modification through five different conceptual domains, i.e., 1) signals, 2) reasons, 2) promises, 4) challenges and 5) steps ahead.Expert opinion: The road ahead will not be traveled without major challenges. Further research to evaluate the positive and negative impacts of the nomenclature change is warranted. However, this modification should encourage increased disease awareness among policymakers and stimulate public and private investments leading to more effective therapy development.

Moderate alcohol consumption is associated with advanced fibrosis in non-alcoholic fatty liver disease and shows a synergistic effect with type 2 diabetes mellitus

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is the most common chronic liver disease worldwide. Whether moderate alcohol consumption plays a role for progression of NAFLD is disputed. Moreover, it is not known which tool is ideal for assessment of alcohol consumption in NAFLD. This study aimed to evaluate if moderate alcohol consumption assessed with different methods, including the biological marker phosphatidylethanol (PEth), is associated with advanced fibrosis in NAFLD.

METHODS

We conducted a cross-sectional study of patients with biopsy-proven NAFLD. All participants were clinically evaluated with medical history, blood tests, and anthropometric measurements. Alcohol consumption was assessed using PEth in blood, the questionnaire AUDIT-C, and clinical interview.

FINDINGS

86 patients were included of which 17% had advanced fibrosis. All participants reported alcohol consumption < 140 g/week. Average weekly alcohol consumption was higher in the group with advanced fibrosis. Moderate alcohol consumption, independently of the method of assessment, was associated with increased probability of advanced fibrosis (adjusted OR 5.5-9.7, 95% CI 1.05-69.6). Patients with type 2 diabetes mellitus (T2DM) consuming moderate amounts of alcohol had a significantly higher rate of advanced fibrosis compared with those consuming low amounts (50.0-60.0% vs. 3.3-21.6%, p < 0.05).

CONCLUSIONS

Moderate alcohol consumption, irrespective of assessment method (clinical interview, AUDIT-C, and PEth), was associated with advanced fibrosis. PEth in blood ≥ 50 ng/mL may be a biological marker indicating increased risk for advanced fibrosis in NAFLD. Patients with T2DM consuming moderate amounts of alcohol had the highest risk of advanced fibrosis, indicating a synergistic effect of insulin resistance and alcohol on the histopathological progression of NAFLD.

Paraphenylenediamine and related chemicals as allergens responsible for allergic contact dermatitis

INTRODUCTION

Paraphenylenediamine (PPDA) is a chemical with strong sensitizing properties used for dyeing of hair and textiles. Paraphenylenediamine can cross-react, resulting in allergy to other related compounds. The prevalence of PPDA sensitization varies widely. The objectives were to assess the frequency of positive patch test reactions to PPDA and related chemicals among patients with allergic contact dermatitis (ACD) and to analyze them regarding their clinical pattern, occupation and cross-reactions.

MATERIAL AND METHODS

The sociodemographic and clinical data of patients with positive patch tests to PPDA, N-isopropyl-N-phenyl-4-phenylenediamine (IPPD), ethylenediamine (EDA), triethylenetetramine (TETA) and toluene-2,5-diamine (TDA) were analyzed. The frequency, strength and cross-reactions with other chemicals were assessed.

RESULTS

Of 4087 ACD patients patch-tested between 2006 and 2015, positive reactions to PPDA and other amines were found in 166 (4.1%). The occupational character of PPDA allergy was established in 34.3% of patients. Personal history of atopy was reported by 36.7% of patients. In 98% of those examined, allergy presented as ACD, most frequently affecting hands. Hypersensitivity to PPDA was diagnosed in 77.1%, to IPPD in 20.5%, to TDA in 6%, to TETA in 1.2%, and to EDA in 0.6% of cases. The patients with an extremely strong PPDA reaction significantly more frequently showed reactions to other para group chemicals, especially to benzocaine.

CONCLUSIONS

Paraphenylenediamine was a major cause of contact allergy of diverse clinical picture more often affecting women, especially with atopy. Every fifth PPDA-allergic person exhibited hypersensitivity to other related compounds. Strong reactions to PPDA increased the risk of cross-reactions.

Pretransplant ascites and encephalopathy and their influence on survival and liver graft rejection in alcoholic cirrhosis disease

INTRODUCTION

The Child-Pugh and model for end-stage liver disease (MELD) scores are widely used to predict the outcomes of liver transplant (LT). Both have similar prognostic values in most cases, although their benefits might differ in some specific conditions. The aim of our study was to analyze the influence of pre-transplant ascites and encephalopathy in post-transplant liver rejection development and survival in alcohol cirrhosis (AC) patients undergoing LT to determine the usefulness of the Child-Pugh score for the assessment of prognosis in such patients.

MATERIAL AND METHODS

Two hundred and eighty-one AC patients, classified according to viral infections and pre-transplant complications, were analyzed. Acute (AR) and chronic (CR) liver rejections and Child-Pugh, MELD and albumin-bilirubin (ALBI) scores were studied in all cases.

RESULTS

Similar AC rejection percentages were observed in ascites or encephalopathy groups (18.5% and 16.5%, p = 0.735), although a higher but not statistically significant AC rate was observed in patients with grade III ascites (p = 0.777) and with grade II encephalopathy (p = 0.089). Chronic rejection was only developed by 9.1% of AC patients, regardless of the presence of ascites (6.2%) or encephalopathy (5.5%). The presence of ascites and encephalopathy complications did not seem to influence post-transplant survival. Neither the Child-Pugh nor the ALBI score can be considered the best for predicting patient survival in the short or long term.

CONCLUSIONS

Ascites and encephalopathy do not seem to influence AC or CR in patient survival, regardless of the presence of viral infections, so in our study neither the Child-Pugh nor ALBI score seems to be the best score to predict the outcomes of these patients.

[Mixed steatohepatitis: more questions than answers (Part 1)]

The term steatohepatitis is used for a heterogeneous group of diseases of various etiologies, characterized by a similar morphological picture. Earlier the diagnosis of non-alcoholic fatty liver disease implied the exclusion of other causes of steatohepatitis, in recent years it has been suggested that a combination of various etiological variants of steatohepatitis is possible. The review considers the terminological, epidemiological and pathogenetic aspects of the most common combination: metabolic and alcoholic genesis, the issues of the mutual influence of etiopathogenetic factors and the identification of the predominant process. Issues of existing and prospective pathogenetic and symptomatic therapy are discussed in detail. Treatment of steatohepatitis is based on the elimination of known causal factors and lifestyle modification; therapy includes medications, that have been proven to be effective in certain types of steatohepatitis and symptomatic therapy as well.

Established and emerging factors affecting the progression of nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) has become the most common chronic liver disease affecting approximately 25% of the global population. Although a majority of NAFLD patients will never experience liver-related symptoms it is estimated that 5-10% will develop cirrhosis-related complications with risk of death or need for liver transplantation. NAFLD is closely associated with cardiovascular disease and components of the metabolic syndrome. However, NAFLD is not uncommon in lean individuals and may in these subjects represent a different entity with separate pathophysiological mechanisms involved implying a higher risk for development of end-stage liver disease. There is considerable fluctuation in the histopathological course of NAFLD that may partly be attributed to lifestyle factors and dietary composition. Nutrients such as fructose, monounsaturated fatty acids, and trans-fatty acids may aggravate NAFLD. Presence of type 2 diabetes mellitus seems to be the most important clinical predictor of liver-related morbidity and mortality in NAFLD. Apart from severity of the metabolic syndrome, genetic polymorphisms and environmental factors, such as moderate alcohol consumption, may explain the variation in histopathological and clinical outcome among NAFLD patients.

Effect of alcohol consumption and the presence of fatty liver on the risk for incident type 2 diabetes: a population-based longitudinal study

INTRODUCTION

Both fatty liver disease (FLD) and alcohol consumption have been reported to affect incident type 2 diabetes mellitus. The aim of this study was to evaluate the combined effect of FLD and alcohol consumption on incident type 2 diabetes.

RESEARCH DESIGN AND METHODS

In this historical cohort study involving 9948 men, we investigated the influence of the presence of FLD and the grades of alcohol consumption on incident type 2 diabetes using Cox proportional hazards models. We categorized the participants into the following four groups: none or minimal alcohol consumption, <40 g/week; light, 40-140 g/week; moderate, 140-280 g/week; or heavy alcohol consumption, >280 g/week. FLD was diagnosed by abdominal ultrasonography.

RESULTS

During the median 6.0-year follow-up, 568 participants developed type 2 diabetes. Heavy alcohol consumers with FLD showed a higher risk for developing type 2 diabetes compared with the other groups. Moderate alcohol consumers without FLD had a significantly higher risk for developing incident type 2 diabetes, compared with none or minimal and light alcohol consumers without FLD. In contrast, there was no apparent difference in the risk for incident type 2 diabetes between none or minimal, light, and moderate alcohol consumers with FLD. Furthermore, there was no statistically significant difference in the risk for incident type 2 diabetes between a moderate and heavy alcohol consumer without FLD and a none or minimal, light, and moderate alcohol consumer with FLD.

CONCLUSIONS

To prevent incident type 2 diabetes, we should acknowledge that the impact of alcohol consumption may vary in the presence of FLD.

Implications of Tobacco Smoking and Alcohol Consumption on Ectopic Fat Deposition in Individuals After Pancreatitis

OBJECTIVES

Tobacco smoking and alcohol consumption are established risk factors for pancreatitis. This study investigated the associations between tobacco smoking/alcohol consumption in people after an attack of pancreatitis and intrapancreatic fat deposition (IPFD), intrahepatic fat deposition (IHFD), and skeletal muscle (SMFD) fat deposition.

METHODS

In this cross-sectional study, magnetic resonance imaging was used to quantify IPFD, IHFD, and SMFD by 2 independent raters. A validated questionnaire was used to determine tobacco smoking and alcohol consumption.

RESULTS

A total of 119 individuals after an attack of pancreatitis were included. Average tobacco smoking contributed most to variance in IPFD (R = 6.5%) and least to variance in SMFD (R = 0.4%). Average alcohol consumption contributed most to variance in variance in IPFD (R = 2.8%) and least to IHFD (R = 1.1%). Packs/day contributed more than years of smoking to variance in IPFD (R = 4.9 and 0.2%, correspondingly), whereas years of drinking contributed more than average daily alcohol consumption (R = 3.9 and 3.2%, correspondingly).

CONCLUSIONS

Tobacco smoking and alcohol consumption contributed more to variance in IPFD than IHFD and SMFD. Smoking contributed more than drinking to variance in IPFD. The daily amount of tobacco smoked appeared to be more important than years of smoking for IPFD.

Prevalence of liver disease in Colombia between 2009 and 2016

BACKGROUND AND AIM

Liver disease refers to a set of pathologies resulting from the interruption of liver function or the poor functioning of the liver. The estimation of morbidity and mortality due to liver disease and the context in which the disease develops are determining factors for public policies related to liver disease and its causes. The primary etiologies are cirrhosis and hepatocellular carcinoma, which are directly related to hepatitis B and C virus and alcohol consumption. Followed by hepatotoxic drug use, autoimmune hepatitis, cholestatic diseases, genetic abnormalities, and nonalcoholic steatohepatitis.

METHODS

A descriptive cross-sectional study was conducted to estimate the prevalence of liver disease in Colombia between 2009 and 2016. Using the Data Warehouse-Cube of SISPRO as the primary source of the data, prevalence proportions were calculated and adjusted according to the Bennett Horiuchi method. The relationship with alcohol consumption and the index of unsatisfied basic needs based on estimates from 2005 were considered as sociodemographic variables.

RESULTS

The prevalence of liver disease differs with regard to the type of illness, sex and age of the patient, access to medical attention, and geographical location.

CONCLUSIONS

As liver disease is a public health problem, it requires early intervention such as raising awareness and prevention strategies, along with postdiagnosis care channels for treatment, rehabilitation, and palliation. By implementing these strategies, public health will be positively impacted, health care resources will be optimized, and more productive years of life are available for the citizens of the country.

Alcohol-related liver disease: Clinical practice guidelines by the Latin American Association for the Study of the Liver (ALEH)

Alcohol-related liver disease (ALD) is a major cause of advanced chronic liver disease in Latin-America, although data on prevalence is limited. Public health policies aimed at reducing the alarming prevalence of alcohol use disorder in Latin-America should be implemented. ALD comprises a clinical-pathological spectrum that ranges from steatosis, steatohepatitis to advanced forms such as alcoholic hepatitis (AH), cirrhosis and hepatocellular carcinoma. Besides genetic factors, the amount of alcohol consumption is the most important risk factor for the development of ALD. Continuous consumption of more than 3 standard drinks per day in men and more than 2 drinks per day in women increases the risk of developing liver disease. The pathogenesis of ALD is only partially understood and recent translational studies have identified novel therapeutic targets. Early forms of ALD are often missed and most clinical attention is focused on AH, which is defined as an abrupt onset of jaundice and liver-related complications. In patients with potential confounding factors, a transjugular biopsy is recommended. The standard therapy for AH (i.e. prednisolone) has not evolved in the last decades yet promising new therapies (i.e. G-CSF, N-acetylcysteine) have been recently proposed. In both patients with early and severe ALD, prolonged abstinence is the most efficient therapeutic measure to decrease long-term morbidity and mortality. A multidisciplinary team including alcohol addiction specialists is recommended to manage patients with ALD. Liver transplantation should be considered in the management of patients with end-stage ALD that do not recover despite abstinence. In selected cases, increasing number of centers are proposing early transplantation for patients with severe AH not responding to medical therapy.

Chronic Alcohol Consumption is Inversely Associated with Insulin Resistance and Fatty Liver in Japanese Males

We aimed to elucidate the effect of chronic alcohol consumption on fatty liver. We assessed the consumption of alcohol in 2429 Japanese males (mean age: 54.2 ± 9 years); they were classified according to average consumption into non-drinkers (ND), light drinkers (LD), moderate drinkers (MD), and heavy drinkers (HD). The prevalence of fatty liver was the lowest in the MD and highest in the ND group (p < 0.001), while obesity was not significantly different among the groups (p = 0.133). Elevated levels of alanine aminotransferase (ALT) were the lowest in the MD group (p = 0.011) along with resistance to insulin (homeostasis model assessment-insulin resistance (HOMA-IR)), which was highest in the ND group (p = 0.001). Chronic consumption of alcohol was independently and inversely associated with fatty liver and insulin resistance after adjusting for obesity, hypertension, fasting hyperglycemia, habit of drinking sweet beverages, physical activity, and age (odds ratios are as follows: ND, 1; LD, 0.682; MD, 0.771; HD, 0.840 and ND, 1; LD, 0.724; MD, 0.701; HD, 0.800, respectively). We found that regardless of the type of alcoholic beverage, chronic consumption of alcohol is inversely associated with insulin resistance and fatty liver in Japanese males. This study had limitations, most notably the lack of investigation into diet and nutrition.

Carotenoids and fatty liver disease: Current knowledge and research gaps

Carotenoids form an important part of the human diet, consumption of which has been associated with many health benefits. With the growing global burden of liver disease, increasing attention has been paid on the possible beneficial role that carotenoids may play in the liver. This review focuses on carotenoid actions in non-alcoholic fatty liver disease (NAFLD), and alcoholic liver disease (ALD). Indeed, many human studies have suggested an association between decreased circulating levels of carotenoids and increased incidence of NAFLD and ALD. The literature describing supplementation of individual carotenoids in rodent models of NAFLD and ALD is reviewed, with particular attention paid to β-carotene and lycopene, but also including β-cryptoxanthin, lutein, zeaxanthin, and astaxanthin. The effect of beta-carotene oxygenase 1 and 2 knock-out mice on hepatic lipid metabolism is also discussed. In general, there is evidence to suggest that carotenoids have beneficial effects in animal models of both NAFLD and ALD. Mechanistically, these benefits may occur via three possible modes of action: 1) improved hepatic antioxidative status broadly attributed to carotenoids in general, 2) the generation of vitamin A from β-carotene and β-cryptoxanthin, leading to improved hepatic retinoid signaling, and 3) the generation of apocarotenoid metabolites from β-carotene and lycopene, that may regulate hepatic signaling pathways. Gaps in our knowledge regarding carotenoid mechanisms of action in the liver are highlighted throughout, and the review ends by emphasizing the importance of dose effects, mode of delivery, and mechanism of action as important areas for further study. This article is part of a Special Issue entitled Carotenoids recent advances in cell and molecular biology edited by Johannes von Lintig and Loredana Quadro.

Prevalence and risk factors of non-alcoholic fatty liver disease in southwest Iran: a population-based case-control study

Aim of the study

Few population-based studies have been conducted to report the prevalence of non-alcoholic fatty liver disease (NAFLD) and determine its risk factors in Iran, particularly in Shahrekord, southwest Iran. The main aim of this population-based, case-control study was to determine the prevalence of NAFLD and its potential risk factors in an Iranian population-based cohort study in Shahrekord, Iran.

Material and methods

We compared 1153 cases with NAFLD at 35 to 70 years to 1153 frequency-matched NAFLD-free controls from a population-based Shahrekord cohort study. Data collection and assessed risk factors (demographics, anthropometrics, clinical and biochemical factors, and laboratory tests) were performed based on the Shahrekord cohort study protocol. Chi-square test, stepwise selection with backward likelihood ratio, logistic regression and log-binomial regression model with 95% confidence interval were performed to determine risk factors with significant effects on NAFLD.

Results

In this study, the mean (± standard deviation) age of the participants was 50.23 (±8.70) years. The prevalence of NAFLD and metabolic syndrome with 95% confidence interval were 16.47% (15.61-17.36%) and 32.74% (30.83-34.70%), respectively. There was a significant difference in the frequency of waist circumstance, triglycerides, body mass index, blood pressure, and alanine aminotransferase between cases and controls (p < 0.001). According to log-binomial model results, socioeconomic status, hypertension, diabetes, and physical activity were significantly associated with NAFLD.

Conclusions

Our findings have important clinical and public health implications in southwest Iran for monitoring the prevalence of NAFLD and important risk factors to manage, screen, prevent, and reduce NAFLD and related factors.

Effect of Alcohol Consumption on Survival in Nonalcoholic Fatty Liver Disease: A National Prospective Cohort Study

Nonalcoholic fatty liver disease (NAFLD) comprises more than two thirds of patients with chronic liver disease in the United States. The effect of alcohol consumption on survival in patients with NAFLD is not clear. We gathered data on National Health and Nutrition Examination Survey participants from 1988 to 2010, and linked them to the National Death Index for follow-up of their survival. We diagnosed NAFLD based on a previously validated biochemical model (Hepatic Steatosis Index). We built multivariate Cox proportional hazards models to evaluate the effect of alcohol consumption on survival of patients with NAFLD. After excluding participants with significant alcohol use, viral hepatitis, or increased transferrin saturation, 4,568 participants with NAFLD were included in the analysis. In a Cox model adjusted for age, sex, and smoking history, drinking 0.5-1.5 drinks per day decreased the risk of overall mortality by 41% (hazard ratio [HR] = 0.59, 95% confidence interval [CI] 0.40-0.85, P = 0.005) compared with not drinking. Drinking ≥1.5 drinks per day showed a trend toward harm (HR = 1.16, 95% CI 0.99-1.36, P = 0.119). After further adjustment for race, physical activity, education level, diabetes, and fiber and polyunsaturated fatty acid intake, drinking 0.5-1.5 drinks per day continued to show a significant protective effect (HR = 0.64, 95% CI 0.42-0.97, P = 0.035), and drinking ≥1.5 drinks per day showed a significant harmful effect on mortality (HR = 1.45, 95% CI 1.01-2.10, P = 0.047). Among patients with NAFLD, modest alcohol consumption is associated with a significant decrease in all-cause mortality, whereas drinking ≥1.5 drinks per day is associated with an increase in mortality. These results help to inform the discussion of potential risks and benefits of alcohol use in patients with NAFLD.

Targeting Myeloid-Derived Cells: New Frontiers in the Treatment of Non-alcoholic and Alcoholic Liver Disease

Non-alcoholic fatty liver disease (NAFLD) and Alcoholic Liver Disease (ALD) are major causes of liver-related morbidity and mortality and constitute important causes of liver transplantation. The spectrum of the liver disease is wide and includes isolated steatosis, steatohepatitis, and cirrhosis. The treatment of NAFLD and ALD remains, however, an unmet need, and therefore it is a public health priority to develop effective treatments for these diseases. Alcoholic and non-alcoholic liver disease share common complex pathogenetic pathways that involve different organs and systems beyond the liver, including the gut, the adipose tissue, and the immune system, which cross-talk to generate damage. Myeloid-derived cells have been widely studied in the setting of NAFLD and ALD and are implicated at different levels in the onset and progression of this disease. Among these cells, monocytes and macrophages have been found to be involved in the induction of inflammation and in the progression to fibrosis, both in animal models and clinical studies and they have become interesting potential targets for the treatment of both NAFLD and ALD. The different mechanisms by which these cells can be targeted include modulation of Kupffer cell activation, monocyte recruitment in the liver and macrophage polarization and differentiation. Evidence from preclinical studies and clinical trials (some of them already in phase II and III) have shown encouraging results in ameliorating steatohepatitis, fibrosis, and the metabolic profile, individuating promising candidates for the pharmacological treatment of these diseases. The currently available results of myeloid-derived cells targeted treatments in NAFLD and ALD are covered in this review.

Association of thirty-year alcohol consumption typologies and fatty liver: Findings from a large population cohort study

OBJECTIVE

To evaluate the longitudinal relationship between repeated measures of alcohol consumption and risk of developing fatty liver.

PATIENTS AND METHODS

This study includes 5407 men and women from a British population-based cohort, the Whitehall II study of civil servants, who self-reported alcohol consumption by questionnaire over approximately 30 years (1985-1989 through to 2012-2013). Drinking typologies during midlife were linked to measures of fatty liver (the fatty liver index, FLI) when participants were in older age (age range 60-84 years) and adjusted for age, socio-economic position, ethnicity, and smoking.

RESULTS

Those who consistently drank heavily had two-fold higher odds of increased FLI compared to stable low-risk moderate drinkers after adjustment for covariates (men: OR = 2.04, 95%CI = 1.53-2.74; women: OR = 2.24, 95%CI = 1.08-4.55). Former drinkers also had an increased FLI compared to low-risk drinkers (men: OR = 2.09, 95%CI = 1.55-2.85; women: OR = 1.68, 95%CI = 1.08-2.67). There were non-significant differences in FLI between non-drinkers and stable low-risk drinkers. Among women, there was no increased risk for current heavy drinkers in cross sectional analyses.

CONCLUSION

Drinking habits among adults during midlife affect the development of fatty liver, and sustained heavy drinking is associated with an increased FLI compared to stable low-risk drinkers. After the exclusion of former drinkers, there was no difference between non-drinkers and low-risk drinkers, which does not support a protective effect on fatty liver from low-risk drinking. Cross-sectional analyses among women did not find an increased risk of heavy drinking compared to low-risk drinkers, thus highlighting the need to take a longitudinal approach.

In vivo antioxidant activity of mackerel (Scomber japonicus) muscle protein hydrolysate

Pacific chub mackerel (Scomber japonicus) is an important fish throughout the world, especially in East Asian countries, including Korea, China, and Japan. Protein hydrolysates from marine sources are commonly used as nutritional supplements, functional ingredients, and flavor enhancers in the food, beverage, and pharmaceutical industries. Antioxidants isolated from fish are relatively easy to prepare, are cost effective, and have no reported side effects. Hence, the present study aimed to investigate the in vivo antioxidant activities of mackerel muscle protein hydrolysate (MMPH) prepared using Protamex. The in vivo bioactivities of MMPH were investigated in alcoholic fatty liver mice (C57BL/6). Serum alanine aminotransferase and aspartate aminotransferase levels were comparable in test and control mice, whereas serum triglyceride and lipid peroxidation levels significantly (p < 0.05; p < 0.001) decreased after administration of MMPH (100-500 mg kg^-1), especially at a concentration of 100 mg kg^-1. A significant (p < 0.05) reduction in xanthine oxidase activity was observed in all groups treated with MMPH (100-500 mg kg^-1), as compared with the control group. Significantly (p < 0.05) higher superoxide dismutase (SOD) activity/protein expression and regulated catalase (CAT) activity/protein expression levels were observed in groups administered MMPH (100-500 mg kg^-1), especially at a concentration of 100 mg kg^-1. These results show that the abundant amino acids of S. japonicus play an important role in the cytosol of the liver cells by directly participating in the expression of xanthine oxidase and the detoxifying SOD and CAT proteins, thereby enhancing antioxidant ability and ultimately, inhibiting lipid peroxidation. This study demonstrated that muscle protein hydrolysate from S. japonicus has strong antioxidant activities.