Role of leisure-time physical activity in nonalcoholic fatty liver disease: a population-based study

Leisure-Time Physical Activity, Time Spent Sitting and Risk of Non-alcoholic Fatty Liver Disease: A Cross-Sectional Study in Puglia

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is the most common chronic liver disease in the world. The increasingly sedentary lifestyle in recent years may have accelerated the development of NAFLD, independent of the level of physical activity.

OBJECTIVE

The purpose of this cross-sectional study was to determine the association between leisure-time physical activity (LTPA) and time spent sitting (TSS) and the likelihood of developing NAFLD in a sample of men and women aged 18-64 years, from southern Italy.

DESIGN

The study is based on two cohort studies, a randomized clinical trial and an observational cost-benefit study.

PARTICIPANTS

A total of 1269 participants (51.5% women) drawn from 3992 eligible subjects were enrolled in this study.

EXPOSURES

Leisure-time physical activity (LTPA) and time spent sitting (TSS) were assessed using the Italian long form of the International Physical Activity Questionnaire (IPAQ-LF), designed for administration to adults aged 18 to 65 years.

MAIN MEASURES

The association of exposures with the probability of belonging to a certain NAFLD degree of severity.

KEY RESULTS

The probability of having mild, moderate, and severe NAFLD tends to decrease with increasing LTPA and decreasing TSS levels. We selected a combination of participants aged 50 years and older stratified by gender. Men had a statistically significant difference in the probability of developing moderate NAFLD if they spent 70 h per week sitting and had low LTPA, while among women there was a statistically significant difference in the probability of developing mild or moderate NAFLD if they had moderate LPTA and spent 35-70 h/week sitting.

CONCLUSIONS

The study thus showed that the amount of LTPA and the amount of TSS are associated with development and progression of NAFLD, but this relationship is not a linear one-especially in women aged ≥ 50 years old.

Non-Alcoholic Fatty Liver Disease and Coronary Artery Disease: A Bidirectional Association Based on Endothelial Dysfunction

Non-alcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver disease and is regarded as a liver manifestation of metabolic syndrome. It is linked to insulin resistance, obesity, and diabetes mellitus, all of which increase the risk of cardiovascular complications. Endothelial dysfunction (EnD) constitutes the main driver in the progression of atherosclerosis and coronary artery disease (CAD). Several pathophysiological alterations and molecular mechanisms are involved in the development of EnD in patients with NAFLD. Our aim is to examine the association of NAFLD and CAD with the parallel assessment of EnD, discussing the pathophysiological mechanisms and the genetic background that underpin this relationship. This review delves into the management of the condition, exploring potential clinical implications and available medical treatment options to facilitate the deployment of optimal treatment strategies for these patients.

Association of physical activity, including amount and maintenance, with the risk of HCC among patients with type 2 diabetes

Background & Aims

We investigated the association of physical activity (PA) levels and changes with the risk of hepatocellular carcinoma (HCC) in patients with type 2 diabetes.

Methods

Patients with type 2 diabetes who had undergone health examinations in 2009 and 2011 were enrolled. In total, 1,439,152 patients were included in the analysis. The level of PA was classified as inactive (<500 metabolic equivalent task [MET]-min/week), moderately active (500-1,500 MET-min/week), and active (≥1,500 MET-min/week). Change in PA was categorized as persistently inactive PA, newly active PA, active PA quitter, and persistently active PA according to change of PA between 2009 and 2011.

Results

During a median of 5.2 years of follow-up, 22,686 patients developed HCC. Compared to the inactive group, the risk of HCC was significantly lower in the moderately active (adjusted hazard ratio [aHR] 0.96, 95% CI 0.93-0.99), and active (aHR 0.95, 95% CI 0.91-0.99) groups. The patients in the persistently active PA group had a significantly lower risk of HCC than those in the persistently inactive PA group (aHR 0.91, 95% CI 0.84-0.98).

Conclusions

Physical activity exhibited a dose-responsive preventive effect against HCC in patients with diabetes.

Impact and implications

Our study investigated the impact of physical activity (PA) levels and changes on the risk of hepatocellular carcinoma (HCC) in patients with type 2 diabetes. PA was associated with a dose-responsive preventive effect against HCC. Patients in the persistently active PA group had a significantly lower risk of HCC than those in the persistently inactive PA group, while newly active patients and PA quitters had similar risks to the persistently inactive group. Our study highlighted the importance of maintaining regular PA as a preventive strategy against HCC.

Rapid improvement of hepatic steatosis and liver stiffness after metabolic/bariatric surgery: a prospective study

Metabolic dysfunction-associated steatotic liver disease (MASLD) and related steatohepatitis (MASH) are common among obese patients and may improve after metabolic/bariatric surgery (MBS). 93 Patients undergoing MBS in 2021-2022 were prospectively enrolled. Liver stiffness measurement (LSM; via vibration-controlled transient elastography [VCTE], point [pSWE] and 2D [2DSWE] shear wave elastography) and non-invasive steatosis assessment (via controlled attenuation parameter [CAP]) were performed before (baseline [BL]) and three months (M3) after surgery. 93 patients (median age 40.9 years, 68.8% female, median BL-BMI: 46.0 kg/m2) were included. BL-liver biopsy showed MASLD in 82.8% and MASH in 34.4% of patients. At M3 the median relative total weight loss (%TWL) was 20.1% and the median BMI was 36.1 kg/m2. LSM assessed by VCTE and 2DSWE, as well as median CAP all decreased significantly from BL to M3 both in the overall cohort and among patients with MASH. There was a decrease from BL to M3 in median levels of ALT (34.0 U/L to 31 U/L; p = 0.025), gamma glutamyl transferase (BL: 30.0 to 21.0 U/L; p < 0.001) and MASLD fibrosis score (BL: - 0.97 to - 1.74; p < 0.001). Decreasing LSM and CAP, as well as liver injury markers suggest an improvement of MASLD/MASH as early as 3 months after MBS.

Effect of different exercise modalities on nonalcoholic fatty liver disease: a systematic review and network meta-analysis

Physical exercise intervention can significantly improve the liver of patients with Non-alcoholic fatty liver disease (NAFLD), but it is unknown which exercise mode has the best effect on liver improvement in NAFLD patients. Therefore, we systematically evaluated the effect of exercise therapy on liver and blood index function of NAFLD patients through network meta-analysis (NMA). Through systematic retrieval of PubMed, Cochrane Library, Web of Science, EBSCO, and CNKI (National Knowledge Infrastructure), two reviewers independently screened the literature, extracted data, and assessed the risk of bias of the included studies by means of databases from inception to January 2023. The NMA was performed using the inconsistency model. A total of 43 studies, 2070 NAFLD patients were included: aerobic training (n = 779), resistance training (n = 159), high-intensity interval training (n = 160), aerobic training + resistance training (n = 96). The results indicate that aerobic training + resistance training could significantly improve serum total cholesterol (TC) (Surface under the cumulative ranking curve (SUCRA) = 71.7), triglyceride (TG) (SUCRA = 96.8), low-density lipoprotein cholesterol (LDL-C) (SUCRA = 86.1) in patients with NAFLD including triglycerides. Aerobic training is the best mode to improve ALT (SUCRA = 83.9) and high-density lipoprotein cholesterol (HDL-C) (SUCRA = 72.3). Resistance training is the best mode to improve aspartate transaminase (AST) (SUCRA = 81.7). Taking various benefits into account, we believe that the best modality of exercise for NAFLD patients is aerobic training + resistance training. In our current network meta-analysis, these exercise methods have different effects on the six indicators of NAFLD, which provides some reference for further formulating exercise prescription for NAFLD patients.

Trends in Oxidative Balance Score and Prevalence of Metabolic Dysfunction-Associated Steatotic Liver Disease in the United States: National Health and Nutrition Examination Survey 2001 to 2018

BACKGROUND

Most studies have primarily focused on assessing the association between diet or exercise patterns and metabolic dysfunction-associated steatotic liver disease (MASLD). This study adopted a more comprehensive approach by introducing the oxidative balance score (OBS) to evaluate the combined effects of diet and lifestyle on the body's antioxidant ability. Our main objective was to investigate the association between OBS and the burden of MASLD in the United States.

METHODS

Participants with complete information from 2001 to 2018 were included. In the absence of other definite liver injury factors, the United States fatty liver index (us-FLI) ≥ 30 was used as the diagnostic criterion for MASLD. We first calculated the weighted prevalence for each cycle and stratified it according to demographic and metabolic-related disease characteristics. Subsequently, weighted multiple logistic regression was used to evaluate the relationship between OBS and MASLD. In addition, we explored the body's inflammatory state and the level of insulin resistance (IR) in mediating OBS and MASLD.

RESULTS

From 2001 to 2018, the prevalence of MASLD in the U.S. population as a whole increased from 29.76% to 36.04%, and the rate was higher in people with metabolic-related diseases. Notably, OBS exhibited a negative correlation with MASLD. Participants in the highest tertile of OBS had a significantly lower prevalence of MASLD compared to those in the lowest tertile [OR: 0.72, 95%CI: (0.57, 0.92), p < 0.001]. Moreover, a high OBS is associated with a lower inflammatory state and level of IR. The body's inflammatory state and IR level mediated the association between OBS and MASLD by 5.2% and 39.7%, respectively (both p < 0.001).

CONCLUSIONS

In this study, we observed an increasing prevalence of MASLD over the years. A higher OBS was associated with a lower risk of MASLD, especially when OBS ≥ 25. The body's inflammatory state and IR level mediate the association between OBS and MASLD, but the mechanism needs to be further investigated.

Physical Activity and Nonalcoholic Fatty Liver Disease: A Roundtable Statement from the American College of Sports Medicine

ABSTRACT

Although physical activity (PA) is crucial in the prevention and clinical management of nonalcoholic fatty liver disease, most individuals with this chronic disease are inactive and do not achieve recommended amounts of PA. There is a robust and consistent body of evidence highlighting the benefit of participating in regular PA, including a reduction in liver fat and improvement in body composition, cardiorespiratory fitness, vascular biology, and health-related quality of life. Importantly, the benefits of regular PA can be seen without clinically significant weight loss. At least 150 min of moderate or 75 min of vigorous intensity PA are recommended weekly for all patients with nonalcoholic fatty liver disease, including those with compensated cirrhosis. If a formal exercise training program is prescribed, aerobic exercise with the addition of resistance training is preferred. In this roundtable document, the benefits of PA are discussed, along with recommendations for 1) PA assessment and screening; 2) how best to advise, counsel, and prescribe regular PA; and 3) when to refer to an exercise specialist.

Aerobic and Muscle-Strengthening Physical Activity, Television Viewing, and Nonalcoholic Fatty Liver Disease: The CARDIA Study

BACKGROUND

The prevalence of non-alcoholic fatty liver disease (NAFLD) in U.S. adults is over 30%, yet the role of lifestyle factors in the etiology of NAFLD remains understudied. We examined the associations of physical activity, by intensity and type, and television viewing with prevalent NAFLD.

METHODS

Cross-sectional analysis of a population-based sample of 2726 Black (49%) and White (51%) adults (Mean (SD) age, 50 (3.6) years; 57.3% female) from the CARDIA study. Exposures were aerobic activity by intensity (moderate, vigorous; hours/week); activity type (aerobic, muscle-strengthening; hours/week); and television viewing (hours/week), examined concurrently in all models and assessed by validated questionnaires. Our outcome was NAFLD (liver attenuation < 51 Hounsfield Units), measured by non-contrast computed tomography, after exclusions for other causes of liver fat. Covariates were sex, age, race, study center, education, diet quality, smoking status, alcohol consumption, and body mass index or waist circumference.

RESULTS

648 participants had NAFLD. In the fully adjusted modified Poisson regression model, the risk ratios per interquartile range of each exposure were moderate-intensity aerobic activity, 1.10 (95% CI, 0.97-1.26); vigorous-intensity aerobic activity, 0.72 (0.63-0.82); muscle-strengthening activity, 0.89 (0.80-1.01); and television viewing, 1.20 (1.10-1.32). Relative to less active participants with higher levels of television viewing, those who participated in ≥2 h/week of both vigorous-intensity aerobic and muscle-strengthening activity and <7 h/week of television viewing had 65% lower risk of NAFLD (risk ratio = 0.35, 95% CI = 0.23-0.51).

CONCLUSION

Adults who follow public health recommendations for vigorous-aerobic and muscle-strengthening activity, as well as minimize television viewing, are considerably less likely to have NAFLD than those who do not follow the recommendations and who have relatively high levels of television viewing.

Associations of physical activity domains and muscle strength exercise with non-alcoholic fatty liver disease: a nation-wide cohort study

It is unclear if various types and domains of exercise have an identical effect on non-alcoholic fatty liver disease (NAFLD). Thus, this study aimed to investigate associations of different physical activity domains and muscle strength exercise with NAFLD using a nation-wide cohort database. Adults aged 20-79 years who participated in the Korean National Health and Nutrition Examination Survey between 2014 and 2018 were analyzed. Hepatic steatosis index was used to identify NAFLD. Physical activity was assessed with the Global Physical Activity Questionnaire. Of 21,015 participants, 4942 (23.5%) had NAFLD. Participants with ≥ 150 min/week of total physical activity had a lower risk of NAFLD than those with < 150 min/week (the fully adjusted OR: 0.86, 95% CI 0.78-0.95). When the individual domain of physical activity was assessed, ≥ 150 min/week of recreation activity was associated with a reduced risk of NAFLD (OR: 0.77, 95% CI 0.67-0.88), whereas ≥ 150 min/week of travel or work activity was not. The fully adjusted OR for NAFLD comparing participants with ≥ 2/week to those with < 2/week of muscle strength exercise was 0.83 (95% CI 0.73-0.94). Muscle strength exercise ≥ 2/week showed a lower risk of NAFLD for all levels of total and each specific domains of physical activity except for ≥ 150 min/week of work activity. An increased level of physical activity and muscle strength exercise was associated with a reduced risk of NAFLD, albeit the effect varied depending on domains of physical activity. Thus, physical activity should be differentiated by domains for the management of NAFLD. Muscle strength exercise could also be a good option for individuals who could not perform moderate-to-vigorous physical activity.

Types of Physical Activity in Nonalcoholic Fatty Liver Disease and All-Cause and Cardiovascular Mortality

The impact of different types of physical activity (PA) on mortality in the context of nonalcoholic fatty liver disease (NAFLD) is not clearly defined and was investigated. This prospective study was performed using the 2007-2014 US National Health and Nutrition Examination Survey with mortality follow-up through 2019. Over a median follow-up of 8.6 years, leisure-time and transportation-related PA that fulfilled the criteria outlined in the PA guidelines (≥150 min/week) in NAFLD were associated with a risk reduction in all-cause mortality (hazard ratio [HR]: 0.76, 95% confidence interval [CI]: 0.59-0.98 for leisure-time PA; HR: 0.62, 95% CI: 0.45-0.86 for transportation-related PA). Leisure-time and transportation-related PA in NAFLD were inversely associated with all-cause mortality in a dose-dependent manner (p for trends <0.01). Furthermore, the risk for cardiovascular mortality was lower in those meeting the PA guidelines for leisure-time PA (HR: 0.63, 95% CI: 0.44-0.91) and transportation-related PA (HR: 0.38, 95% CI: 0.23-0.65). Increasing sedentary behavior was linked to an increased risk of all-cause and cardiovascular mortality (p for trend <0.01). Meeting PA guidelines (≥150 min/week) for leisure-time and transportation-related PA has beneficial health effects on all-cause and cardiovascular mortality among individuals with NAFLD. Sedentary behavior in NAFLD showed harmful effects on all-cause and cardiovascular mortality.

Understanding NAFLD: From Case Identification to Interventions, Outcomes, and Future Perspectives

While non-alcoholic fatty liver disease (NAFLD) is a prevalent and frequent cause of liver-related morbidity and mortality, it is also strongly associated with cardiovascular disease-related morbidity and mortality, likely driven by its associations with insulin resistance and other manifestations of metabolic dysregulation. However, few satisfactory pharmacological treatments are available for NAFLD due in part to its complex pathophysiology, and challenges remain in stratifying individual patient's risk for liver and cardiovascular disease related outcomes. In this review, we describe the development and progression of NAFLD, including its pathophysiology and outcomes. We also describe different tools for identifying patients with NAFLD who are most at risk of liver-related and cardiovascular-related complications, as well as current and emerging treatment options, and future directions for research.

Loss of hepatic phosphoenolpyruvate carboxykinase 1 dysregulates metabolic responses to acute exercise but enhances adaptations to exercise training in mice

Acute exercise increases liver gluconeogenesis to supply glucose to working muscles. Concurrently, elevated liver lipid breakdown fuels the high energetic cost of gluconeogenesis. This functional coupling between liver gluconeogenesis and lipid oxidation has been proposed to underlie the ability of regular exercise to enhance liver mitochondrial oxidative metabolism and decrease liver steatosis in individuals with nonalcoholic fatty liver disease. Herein we tested whether repeated bouts of increased hepatic gluconeogenesis are necessary for exercise training to lower liver lipids. Experiments used diet-induced obese mice lacking hepatic phosphoenolpyruvate carboxykinase 1 (KO) to inhibit gluconeogenesis and wild-type (WT) littermates. 2H/13C metabolic flux analysis quantified glucose and mitochondrial oxidative fluxes in untrained mice at rest and during acute exercise. Circulating and tissue metabolite levels were determined during sedentary conditions, acute exercise, and refeeding postexercise. Mice also underwent 6 wk of treadmill running protocols to define hepatic and extrahepatic adaptations to exercise training. Untrained KO mice were unable to maintain euglycemia during acute exercise resulting from an inability to increase gluconeogenesis. Liver triacylglycerides were elevated after acute exercise and circulating β-hydroxybutyrate was higher during postexercise refeeding in untrained KO mice. In contrast, exercise training prevented liver triacylglyceride accumulation in KO mice. This was accompanied by pronounced increases in indices of skeletal muscle mitochondrial oxidative metabolism in KO mice. Together, these results show that hepatic gluconeogenesis is dispensable for exercise training to reduce liver lipids. This may be due to responses in ketone body metabolism and/or metabolic adaptations in skeletal muscle to exercise.NEW & NOTEWORTHY Exercise training reduces hepatic steatosis partly through enhanced hepatic terminal oxidation. During acute exercise, hepatic gluconeogenesis is elevated to match the heightened rate of muscle glucose uptake and maintain glucose homeostasis. It has been postulated that the hepatic energetic stress induced by elevating gluconeogenesis during acute exercise is a key stimulus underlying the beneficial metabolic responses to exercise training. This study shows that hepatic gluconeogenesis is not necessary for exercise training to lower liver lipids.

Relationship between liver fat content and lifestyle factors in adults with metabolic syndrome

The aim of this study was to investigate the associations between liver fat content (LFC), sedentary behaviour (SB), physical activity (PA), fitness, diet, body composition, and cardiometabolic risk factors in adults with metabolic syndrome. A total of 44 sedentary adults (mean age 58 [SD 7] years; 25 women) with overweight or obesity participated. LFC was assessed with magnetic resonance spectroscopy and imaging, SB and PA with hip-worn accelerometers (26 [SD 3] days), fitness by maximal bicycle ergometry, body composition by air displacement plethysmography and nutrient intake by 4-day food diaries. LFC was not independently associated with SB, PA or fitness. Adjusted for sex and age, LFC was associated with body fat%, body mass index, waist circumference, triglycerides, alanine aminotransferase, and with insulin resistance markers. There was and inverse association between LFC and daily protein intake, which persisted after further adjusment with body fat%. LFC is positively associated with body adiposity and cardiometabolic risk factors, and inversely with daily protein intake. SB, habitual PA or fitness are not independent modulators of LFC. However, as PA is an essential component of healthy lifestyle, it may contribute to liver health indirectly through its effects on body composition in adults with metabolic syndrome.

Quality standards for the management of non-alcoholic fatty liver disease (NAFLD): consensus recommendations from the British Association for the Study of the Liver and British Society of Gastroenterology NAFLD Special Interest Group

Non-alcoholic fatty liver disease (NAFLD) is common, affecting approximately 25% of the general population. The evidence base for the investigation and management of NAFLD is large and growing, but there is currently little practical guidance to support development of services and delivery of care. To address this, we produced a series of evidence-based quality standard recommendations for the management of NAFLD, with the aim of improving patient care. A multidisciplinary group of experts from the British Association for the Study of the Liver and British Society of Gastroenterology NAFLD Special Interest Group produced the recommendations, which cover: management of people with, or at risk of, NAFLD before the gastroenterology or liver clinic; assessment and investigations in secondary care; and management in secondary care. The quality of evidence for each recommendation was evaluated by the Grading of Recommendation Assessment, Development and Evaluation tool. An anonymous modified Delphi voting process was conducted individually by each member of the group to assess the level of agreement with each statement. Statements were included when agreement was 80% or greater. From the final list of statements, a smaller number of auditable key performance indicators were selected to allow services to benchmark their practice. It is hoped that services will review their practice against our recommendations and key performance indicators and institute service development where needed to improve the care of patients with NAFLD.

Effect of Exercise Training on Serum Transaminases in Patients With Nonalcoholic Fatty Liver Disease: A Systematic Review and Meta-Analysis

Background/Purpose: Nonalcoholic fatty liver disease (NAFLD) constitutes a spectrum of liver diseases associated with various metabolic disorders. Exercise interventions reportedly manage the clinical outcomes of NAFLD, but their efficacy depends on exercise as well as characteristics of patient. We hypothesized that exercise could alleviate the elevated transaminases level, which may be associated with the characteristics of patients (age/bodyweight/sex) or exercise variables (frequency/intensity/duration). Therefore, we examined the effect of exercise on serum transaminases, and identified the variables influencing transaminases in NAFLD patients.

Methods: Article search was conducted using electronic databases (PubMed, Web of Science, EMBASE, ScienceDirect, Google Scholar) until December 2021. Studies that involved examination and comparison of the effect of an exercise intervention on alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels in NAFLD/nonalcoholic steatohepatitis patients were included. We calculated pooled effect upon a meta-analysis, determined correlations (between transaminases and characteristics of patients/exercise) by meta-regression, and assessed the influencing variable through subgroup analysis.

Results: A total of 18 studies (22 trials) with 1098 NAFLD patients (exercise = 568; control = 530) were included. The pooled outcomes revealed that exercise intervention significantly decreased both ALT (p = 0.004) and AST (p = 0.001) levels in NAFLD patients. Meta-regression analysis showed decreased ALT (coef. = 1.138, p &lt; 0.01) and AST (coef. = 0.459, p = 0.041) after intervention was correlated with the age of patients. Particularly, patients aged 30–39 years (MD: −25.89 U/L, 95% CI: −36.40 to −15.37, p &lt; 0.00001) and 40–49 years (MD: −12.17 U/L, 95% CI: −20.38 to −3.96, p = 0.004) represented a substantial decrease in ALT levels. Additionally, the 50–59 years age group tended to have decreased ALT levels (MD: −3.94 U/L, 95% CI: −8.19 to 0.31, p = 0.07); however, patients above 60 years did not respond (p = 0.92) to exercise intervention. In contrast, exercise-induced AST reduction was found in only the 30–39 years age group (MD: −11.92 U/L, 95% CI: −16.78 to −7.06, p &lt; 0.00001) and not in patients under the 40–49 (p = 0.19), and 50–59 groups (p = 0.12) and above 60 years (p = 0.15).

Conclusion: Our findings suggest that the age of NAFLD patients may be an important variable in improving the levels of serum transaminases, and clinically young patients may have greater benefits from exercise than older patients.

Physical Activity Is Associated With Nonalcoholic Fatty Liver Disease and Significant Fibrosis Measured by FibroScan

BACKGROUND AND AIMS

Studies evaluating the association of 2018 Physical Activity Guidelines for Americans (PA Guidelines) with nonalcoholic fatty liver disease (NAFLD) and significant fibrosis or cirrhosis are needed. We evaluated the association of meeting PA Guidelines with NAFLD and significant fibrosis or cirrhosis by transient elastography in the United States.

METHODS

A cross-sectional analysis was performed using the 2017-2018 U.S. National Health and Nutrition Examination Survey data. NAFLD and significant fibrosis or cirrhosis were defined by transient elastography in the absence of other causes of chronic liver disease. The detailed PA questionnaire assessed the leisure-time, occupation-related, and transportation-related PA. PA was categorized based on the PA Guidelines.

RESULTS

Of the 4304 subjects, leisure-time PA, which met the PA Guidelines (≥150 min/wk), was associated with 44% lower risk of NAFLD (odds ratio [OR]: 0.56; 95% confidence interval [CI]: 0.46-0.67). Subjects who reported 1-2 times (150-299 min/wk) or over 2 times (≥300 min/wk) the recommended amount of PA Guidelines had 40% (OR, 0.60; 95% CI, 0.41-0.90) and 49% (OR, 0.51; 95% CI, 0.40-0.65) lower odds of NAFLD, respectively. Over 8 hours of sitting time had a 44% higher risk of NAFLD (OR, 1.44; 95% CI, 1.01-2.05) when we considered leisure-time PA and sitting time simultaneously. Over 2 times (≥300 min/wk) the recommended amount of PA Guidelines for leisure-time PA had 59% (OR, 0.41; 95% CI, 0.22-0.74) lower risk for significant fibrosis and 63% (OR, 0.37; 95% CI, 0.21-0.64) lower odds of cirrhosis.

CONCLUSIONS

Meeting PA Guidelines for leisure-time PA has beneficial effects on NAFLD, and over 2 times the recommended amount of PA Guidelines had lower risk for significant fibrosis or cirrhosis.

Non-alcoholic fatty liver disease in adults 2021: A clinical practice guideline of the Italian Association for the Study of the Liver (AISF), the Italian Society of Diabetology (SID) and the Italian Society of Obesity (SIO)

Nonalcoholic fatty liver disease (NAFLD) is a common and emerging liver disease in adults, paralleling the epidemic of obesity and diabetes and leading to worrisome events (hepatocellular carcinoma and end-stage liver disease). In the past years, mounting evidence added insights about epidemiology, natural history, diagnosis and lifestyle-based or drug treatment of NAFLD. In this rapidly evolving scenario, members of the Associazione Italiana per lo Studio del Fegato, the Società Italiana di Diabetologia and the Società Italiana dell'Obesità reviewed current knowledge on NAFLD. The quality of the published evidence is graded, and practical recommendations are made following the rules and the methodology suggested in Italy by the Centro Nazionale per l'Eccellenza delle cure and Istituto Superiore di Sanità. Whenever possible, recommendations are placed within the context the Italian Healthcare system, with reference to specific experience and local diagnostic and management resources.Level of evidence Level of evidence of recommendations for each PICO question were reported according to available evidence.

Glucocorticosteroids and the Risk of NAFLD in Inflammatory Bowel Disease

Each year, the incidence of nonalcoholic fatty liver (NAFLD) disease increases. NAFLD is a chronic disease. One of the most common causes of NAFLD is an inadequate lifestyle, which is characterized by a lack or low physical activity and eating highly processed foods rich in saturated fat and salt and containing low amount of fiber. Moreover, disturbances in intestinal microbiome and the use of certain drugs may predispose to NAFLD. NAFLD is an increasingly described disease in patients with inflammatory bowel disease (IBD). Recent data also indicate a frequent coexistence of metabolic syndrome in this group of patients. Certain groups of drugs also increase the risk of developing inflammation, liver fibrosis, and cirrhosis. Particularly important in the development of NAFLD are steroids, which are used in the treatment of many diseases, for example, IBD. NAFLD is one of the most frequent parenteral manifestations of the disease in IBD patients. However, there is still insufficient information on what dose and exposure time of selected types of steroids may lead to the development of NAFLD. It is necessary to conduct further research in this direction. Therefore, patients with IBD should be constantly monitored for risk factors for the development of NAFLD.

Protective Effect of Leisure-Time Physical Activity and Resistance Training on Nonalcoholic Fatty Liver Disease: A Nationwide Cross-Sectional Study

Background: Nonalcoholic fatty liver disease (NAFLD) is the most common form of chronic liver disease. The present study aimed to investigate the association of NAFLD with leisure-time physical activity (PA) levels and resistance training (RT). Methods: We used data from large nationwide cohorts in Korea. NAFLD was defined based on the Framingham steatosis index. Participants were categorized into four groups based on RT frequency and adherence to PA guidelines (≥150 min/week of moderate-intensity PA): Low-PA, Low-PA+RT, High-PA, and High-PA+RT. Multiple logistic regression models were used to assess the risk of NAFLD according to leisure-time PA levels and regularity of RT. Results: When compared with Low-PA, High-PA decreased the risk of NAFLD by 17%, and High-PA+RT further decreased the risk by 30%. However, the additional reduction in risk associated with the addition of RT was observed in men (19%), but not in women. In the High-PA group, men had a significantly higher training frequency and period for RT than women. Conclusions: Following the PA guideline may confer protective effects against NAFLD, while adding RT to High-PA can further decrease the risk of NAFLD. Sex-based differences in NAFLD risk in the High-PA+RT group may be due to the differences in the frequency and period of RT.

Objectively Measured Physical Activity Is Inversely Associated With Nonalcoholic Fatty Liver Disease: The Rotterdam Study

INTRODUCTION

The disease burden of nonalcoholic fatty liver disease (NAFLD) increases rapidly, in line with the obesity pandemic. Physical activity has been linked to a lower risk of NAFLD. However, the impact of different intensities of activity and sedentary behavior and whether their effects on NAFLD are explained by metabolic health remain unclear.

METHODS

We performed cross-sectional analyses within the population-based Rotterdam Study cohort. Abdominal ultrasound and accelerometry data were collected between 2009 and 2014. NAFLD was defined as hepatic steatosis diagnosed by ultrasound, in the absence of secondary causes for steatosis: viral hepatitis, steatogenic drugs, and excessive alcohol. We categorized accelerometry data into sedentary time and light, moderate, and vigorous physical activities.

RESULTS

We included 667 participants (aged 63.3 ± 6.3 years, 53% female individuals), and 34.3% had NAFLD. Total physical activity was associated with lower NAFLD prevalence adjusted for demographic, lifestyle, and socioeconomic factors (odds ratio: 0.958 per 10 min/d, 95% confidence interval [CI]: 0.929-0.986). More intensive physical activity was more strongly associated with lower NAFLD prevalence: odds ratios for light, moderate, and vigorous physical activities were 0.931 (95% CI: 0.882-0.982), 0.891 (95% CI: 0.820-0.967), and 0.740 (95% CI: 0.600-0.906) per 10 min/d, respectively. These associations were explained by metabolic health, particularly homeostatic model assessment of insulin resistance (proportion mediated: 0.59, P < 0.001) and waist circumference (proportion mediated: 1.08, P < 0.001). Beyond this indirect effect, no direct effect could be demonstrated (P = 0.282-0.827).

DISCUSSION

Physical activity at each intensity is inversely associated with NAFLD prevalence, with larger effects for higher intensities of physical activity. This association is mediated by better metabolic health, mainly lower insulin resistance and waist circumference. Physical activity should therefore be incorporated into NAFLD disease management and prevention programs.

Non-alcoholic fatty liver disease in adults 2021: A clinical practice guideline of the Italian Association for the Study of the Liver (AISF), the Italian Society of Diabetology (SID) and the Italian Society of Obesity (SIO)

Nonalcoholic fatty liver disease (NAFLD) is a common and emerging liver disease in adults, paralleling the epidemic of obesity and diabetes, and leading to worrisome events (hepatocellular carcinoma and end-stage liver disease). In the last years, mounting evidence added insights about epidemiology, natural history, diagnosis and lifestyle-based or drug treatment of NAFLD. In this rapidly evolving scenario, members of the Associazione Italiana per lo Studio del Fegato (AISF), the Società Italiana di Diabetologia (SID) and the Società Italiana dell'Obesità (SIO) reviewed current knowledge on NAFLD. The quality of the published evidence is graded, and practical recommendations are made following the rules and the methodology suggested in Italy by the Centro Nazionale per l'Eccellenza delle cure (CNEC) and Istituto Superiore di Sanità (ISS). Whenever possible, recommendations are placed within the context the Italian Healthcare system, with reference to specific experience and local diagnostic and management resources. Level of evidence: Level of evidence of recommendations for each PICO question were reported according to available evidence.

Adherence to lifestyle modification in patients with nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) makes a major impact on morbidity and mortality among the workingage population in developed countries. In the lack of effective pharmacological methods, the leading role in treatment of NAFLD belongs to lifestyle modification, consistent and gradual weight loss, and its maintenance. The qualitative and quantitative structure of the diet, intensity of physical activity, and most importantly, regularity and consistency of implementation of lifestyle modification activities are the key to successful management of patients with NAFLD.

To date, there are very few studies on adherence to lifestyle modification activities in this group of patients, which is mainly due to a deficiency of methodological tools. The questionnaire “QAA-25” recommended by the Russian Scientific Medical Society of Therapists for quantitative assessment of adherence to treatment allows to assess both adherence to therapy in general and adherence to its individual components (adherence to drug therapy, adherence to medical counseling, and adherence to lifestyle modification), which requires further study taking into account features of therapeutic strategies in treating NAFLD. 

Metabolic benefits of changing sedentary lifestyles in nonalcoholic fatty liver disease: a meta-analysis of randomized controlled trials

This study seeks to evaluate the effects of a reversal of sedentary lifestyles on the improvement of metabolic profiles in patients with NAFLD. The PubMed, Cochrane Library, Web of Science, and CNKI databases were searched up to May 15, 2021. Ten randomized controlled trials on changes in the sedentary lifestyle of patients with NAFLD were included in the analysis. Data from self-controlled case arms of randomized controlled trials investigating sedentary lifestyle alterations were extracted, and the effect size was reported as the MD and 95% CI. A total of 455 participants in 10 studies met the selection criteria. The results showed that changing a sedentary lifestyle can significantly improve ALT [MD = 4.35 (U/L), 95% CI: 0.53, 8.17], CHOL [MD = 0.31 (mmol/L), 95% CI: 0.19, 0.43], TG [MD = 0.22 (mmol/L), 95% CI: 0.10~0.34], LDL-C [MD = 0.30 (mmol/L), 95% CI: 0.02, 0.57], fasting blood glucose [MD = 0.17 (mmol/L), 95% CI: 0.03, 0.31], insulin [MD = 3.23 (pmol/L), 95% CI: 1.37~5.08], and HOMA-IR levels (MD = 0.39, 95% CI: 0.15, 0.63). Changing sedentary lifestyle can also significantly improve body mass index (BMI) [MD = 1.12 (kg/m²), 95% CI: 0.66, 0.58], body fat (%) [MD = 0.34 (%), 95% CI: 0.13, 0.55] and VO_2peak levels [MD = -4.00 (mL/kg/min), 95% CI: -5.93, -2.06]. No differences in AST or GGT were noted before or after lifestyle changes. Altering a sedentary lifestyle to a lifestyle with regular exercise can slightly improve the levels of liver enzymes, blood lipids, blood glucose, insulin resistance, and body mass index in NAFLD patients.

Non-alcoholic fatty liver disease in adults 2021: A clinical practice guideline of the Italian Association for the Study of the Liver (AISF), the Italian Society of Diabetology (SID) and the Italian Society of Obesity (SIO)

Nonalcoholic fatty liver disease (NAFLD) is a common and emerging liver disease in adults, paralleling the epidemic of obesity and diabetes, and leading to worrisome events (hepatocellular carcinoma and end-stage liver disease). In the last years, mounting evidence added insights about epidemiology, natural history, diagnosis and lifestyle-based or drug treatment of NAFLD. In this rapidly evolving scenario, members of the Associazione Italiana per lo Studio del Fegato (AISF), the Società Italiana di Diabetologia (SID) and the Società Italiana dell'Obesità (SIO) reviewed current knowledge on NAFLD. The quality of the published evidence is graded, and practical recommendations are made following the rules and the methodology suggested in Italy by the Centro Nazionale per l'Eccellenza delle cure (CNEC) and Istituto Superiore di Sanità (ISS). Whenever possible, recommendations are placed within the context the Italian Healthcare system, with reference to specific experience and local diagnostic and management resources. Level of evidence: Level of evidence of recommendations for each PICO question were reported according to available evidence.

Synergistic Interaction of Dietary Pattern and Concordance Lifestyle with Abnormal Liver Function among Young Adults in Taiwan: A Population-Based Longitudinal Study

While diet and lifestyle are independently implicated in the etiology of liver disease, the interaction of diet and lifestyle may be more helpful for determining the risk of liver abnormality. Thus, our study aimed to evaluate the interaction between the dietary pattern associated with liver biomarkers and lifestyle factors among Taiwanese adults with abnormal liver enzymes. A liver-associated dietary pattern, generated using reduced rank regression, was characterized by high intake of soy sauce or other dips, sugar sweetened beverages, and preserved and processed foods, but low intake of seafood, fruits, eggs, and dark-colored vegetables. In the fully adjusted model, liver-associated dietary patterns or unhealthy concordance lifestyle factors were associated with an increased risk of having liver function abnormality (OR = 1.08, 95% CI: 1.04, 1.12 and OR = 1.42, 95% CI: 1.31, 1.53, respectively). Moreover, the interaction between liver-associated dietary pattern and unhealthy concordance lifestyle factors showed more significant correlation, with an elevated risk of abnormal liver function (OR = 2.14, 95% CI: 2.02, 2.26). Therefore, our study suggests that participants who have a strong liver-associated dietary pattern along with unhealthy concordance lifestyles are likely to have increased odds of abnormal liver function.

Higher Healthy Lifestyle Score is associated with lower presence of non-alcoholic fatty liver disease in middle-aged and older Chinese adults: a community-based cross-sectional study

OBJECTIVE

Previous studies have reported inverse associations between certain healthy lifestyle factors and non-alcoholic fatty liver disease (NAFLD), but limited evidence showed the synergistic effect of those lifestyles. This study examined the relationship of a combination of lifestyles, expressed as Healthy Lifestyle Score (HLS), with NAFLD.

DESIGN

A community-based cross-sectional study. Questionnaires and body assessments were used to collect data on the six-item HLS (ranging from 0 to 6, where higher scores indicate better health). The HLS consists of non-smoking (no active or passive smoking), normal BMI (18·5-23·9 kg/m2), physical activity (moderate or vigorous physical activity ≥ 150 min/week), healthy diet pattern, good sleep (no insomnia or <6 months) and no anxiety (Self-rating Anxiety Scale < 50), one point each. NAFLD was diagnosed by ultrasonography.

SETTING

Guangzhou, China.

PARTICIPANTS

Two thousand nine hundred and eighty-one participants aged 40-75 years.

RESULTS

The overall prevalence of NAFLD was 50·8 %. After adjusting for potential covariates, HLS was associated with lower presence of NAFLD. The OR of NAFLD for subjects with higher HLS (3, 4, 5-6 v. 0-1 points) were 0·68 (95 % CI 0·51, 0·91), 0·58 (95 % CI 0·43, 0·78) and 0·35 (95 % CI 0·25, 0·51), respectively (P-values < 0·05). Among the six items, BMI and physical activity were the strongest contributors. Sensitivity analyses showed that the association was more significant after weighting the HLS. The beneficial association remained after excluding any one of the six components or replacing BMI with waist circumference.

CONCLUSIONS

Higher HLS was associated with lower presence of NAFLD, suggesting that a healthy lifestyle pattern might be beneficial to liver health.

Physical activity is associated with reduced risk of liver disease in the prospective UK Biobank cohort

BACKGROUND & AIMS

Previous studies have identified physical activity as an important lifestyle factor in the pathogenesis of chronic liver diseases (CLD). However, most studies were short in follow-up, and based on self-reported activity. Moreover, it is unknown whether physical activity affects the risk of liver disease development in the general population. Herein, we aimed to clarify the association between physical activity and CLD by examining the risk of liver disease and progression in relation to accelerometer-based physical activity in a large subset of prospectively recruited participants in the UK Biobank.

METHODS

We analysed data from 96,688 participants that recorded their physical activity through the use of a wrist accelerometer. Relative risks for development of liver diseases were calculated using multivariable-adjusted Cox regression models. In a subgroup of participants without any previously diagnosed liver disease (n = 95,974), a total of 374 liver disease cases were diagnosed during follow-up (mean = 5.5 years).

RESULTS

Participants in the top compared with the bottom quartile of physical activity had a reduced risk of both overall CLD (hazard ratio [HR]: 0.41 [0.29-0.59]) and NAFLD (HR: 0.39 [0.21-0.70]). An activity increase of an additional 2,500 steps per day, was associated with a 38% reduction in CLD and a 47% reduction in NAFLD development, independent of adiposity. In the subgroup of participants with previously diagnosed liver disease (n = 714), participants in the top compared with the bottom quartile of physical activity had a striking 89% risk reduction in liver-related death (HR: 0.11 [0.02-0.86]), and 85% risk reduction in all-cause mortality (adjusted HR: 0.15 [0.05-0.44]). Walking an additional 2,500 steps per day was associated with 44% reduction in liver disease progression.

CONCLUSIONS

Greater physical activity is associated with a dose-dependent reduction in liver disease, which appears to be independent of adiposity.

LAY SUMMARY

In this study, we aimed to clarify the association between accelerometer-measured physical activity and chronic liver disease by examining risk of overall and specific liver diseases and their progression in relation to accelerometer-based physical activity in 96,688 participants in the UK Biobank. Our results show a clear, dose-dependent protective association between accelerometer-measured physical activity and liver disease development and progression. The linkage of device-measured activity could therefore create a framework for using wearables for personalised prevention of liver diseases.

Physical Activity, Measured Objectively, Is Associated With Lower Mortality in Patients With Nonalcoholic Fatty Liver Disease

BACKGROUND & AIMS

The association between physical activity (PA) and all-cause and cause-specific mortality from nonalcoholic fatty liver disease (NAFLD) requires investigation. We studied whether PA, measured by accelerometer, is associated with all-cause and cause-specific mortality among individuals with NAFLD.

METHODS

We performed a longitudinal analysis using the 2003 to 2006 US National Health and Nutrition Examination Survey data of adults (age, ≥20 y) and collecting mortality data through December 2015. NAFLD was defined based on the hepatic steatosis index or US fatty liver index scores, in the absence of other causes of chronic liver disease. PA was measured from participants who wore accelerometers 10 h/d for a minimum of 4 days over a 7-day period and were classified as total PA, moderate to vigorous PA (MVPA), and sedentary behavior.

RESULTS

Over an average follow-up period of 10.6 years, increasing the duration of total PA was associated with a reduced risk of death, from any cause, in an age- and sex-adjusted model (hazard ratio [HR], 0.52; 95% CI, 0.32-0.86 for highest quartile vs lowest quartile; P for trend = .001) and multivariable model (HR, 0.46; 95% CI, 0.28-0.75; P for trend < .001) among individuals with NAFLD. Increasing the duration of MVPA was associated with a lower risk of death from any cause in individuals with NAFLD. Furthermore, longer total PA was associated with a lower risk for cardiovascular disease-related death in individuals with NAFLD (HR, 0.28; 95% CI, 0.08-0.98 for highest quartile vs lowest quartile; P for trend = .007). We did not find this association for cancer-related mortality in individuals with NAFLD. Increasing the duration of sedentary behavior did not affect all-cause or cause-specific mortality in individuals with NAFLD.

CONCLUSIONS

Longer total PA and MVPA, measured by accelerometers over a 7-day period, are associated with lower all-cause and cardiovascular mortality in individuals with NAFLD.

Evidence-Based Aerobic Exercise Training in Metabolic-Associated Fatty Liver Disease: Systematic Review with Meta-Analysis

Background: This meta-analysis evaluates the overall effect of the non-pharmacological intervention, aerobic exercise, upon serum liver enzymes levels, glucose metabolism and anthropometric measures amongst patients with metabolic associated fatty liver disease (MAFLD). It also examines whether the effects on these outcomes are moderated by the aerobic training protocol when considered according to the American College of Sports Medicine (ACSM) recommended FITT (frequency, intensity, time, type) principles. Approach and Results: Fifteen randomized control trials were included in the meta-analysis. Compared with usual care, continuous and interval training showed significant efficacy in alanine aminotransferase (ALT) level improvement (MD = −2.4, 95% CI: −4.34 to −0.46 p = 0.015, I² = 9.1%). Interventions based on all types of aerobic exercise protocols showed significant improvement of intrahepatic triglycerides (MD = −4.0557, 95% CI: −5.3711 to −2.7403, p < 0.0001, I² = 0%) and BMI (MD = −0.9774, 95% CI: −1.4086 to −0.5462, p < 0.0001, I² = 0). Meta-regression analysis demonstrated a significant correlation between total intervention time and ALT level (for all aerobic protocols: 6.0056, se = 2.6896, z = 2.2329, p = 0.02; as well as for continuous and interval aerobic protocols: 5.5069, se = 2.7315, z = 2.016, p = 0.04). Conclusions: All types of aerobic exercise protocols are effective at improving intrahepatic triglycerides and lead to a reduction in body mass index. In addition, continuous and interval aerobic exercise may be more effective at improving ALT ≤12 weeks intervention time benefits the management of MAFLD.

Nonalcoholic Fatty Liver Disease: Focus on New Biomarkers and Lifestyle Interventions

Nonalcoholic fatty liver disease (NAFLD) is considered a hepatic manifestation of metabolic syndrome, characterized from pathological changes in lipid and carbohydrate metabolism. Its main characteristics are excessive lipid accumulation and oxidative stress, which create a lipotoxic environment in hepatocytes leading to liver injury. Recently, many studies have focused on the identification of the genetic and epigenetic modifications that also contribute to NAFLD pathogenesis and their prognostic implications. The present review is aimed to discuss on cellular and metabolic alterations associated with NAFLD, which can be helpful to identify new noninvasive biomarkers. The identification of accumulated lipids in the cell membranes, as well as circulating cytokeratins and exosomes, provides new insights in understanding of NAFLD. This review also suggests that lifestyle modifications remain the main prevention and/or treatment for NAFLD.

Determinants of Physical Activity Engagement in Patients With Nonalcoholic Fatty Liver Disease: The Need for an Individualized Approach to Lifestyle Interventions

OBJECTIVES

Physical activity (PA) is an important non-pharmacological treatment for non-alcoholic fatty liver disease (NAFLD). This study investigated the determinants of PA engagement and awareness of the World Health Organization (WHO) PA guidelines in patients with NAFLD.

METHODS

Study participants were 101 patients with NAFLD (median age: 54 [IQR = 15] y; 53 men and 48 women) who completed 4 questionnaires: (1) a PA guideline awareness questionnaire; (2) a PA questionnaire assessing PA levels; and (3) 2 questionnaires assessing perceived barriers and motivators for engaging in PA. Binary logistic regression was performed to assess predictors of PA levels.

RESULTS

Twenty-four percent of participants correctly identified the recommended WHO weekly PA guidelines, and 39% adhered to the guidelines. Lack of willpower, time, and energy were the most frequently cited barrier domains. Scores for lack of willpower (odds ratio [OR] = 1.445, 95% CI = 1.088-1.919) and lack of resources (OR = 1.378, 95% CI = 1.003-1.893), and reporting 3 or more "significant" barrier domains (OR = 5.348, 95% CI = 1.792-15.873) were significant predictors of PA levels. Maintaining health and fitness was the most cited motivator domain and was a significant predictor (OR = 2.551, 95% CI = 1.253-5.208) of PA levels.

CONCLUSIONS

This study highlights the lack of awareness of the WHO PA guidelines and the key determinants of PA participation in patients with NAFLD. Determinants of PA should be identified at the individual level to create a personalized approach for PA maintenance for people with NAFLD to promote lifelong participation in PA.

IMPACT

This study closes a gap in the published data on the determinants of PA engagement in patients with NAFLD.

LAY SUMMARY

Physical inactivity is the fourth leading cause of global mortality and contributes to many chronic inflammatory diseases, including obesity, type 2 diabetes, cardiovascular disease, and nonalcoholic fatty liver disease (NAFLD). People with NAFLD engage in less physical activity compared with people who are healthy, and this study provides new information that clinicians can use to help these patients increase their physical activity participation.

Extrahepatic Manifestations of Nonalcoholic Fatty Liver Disease

Nonalcoholic fatty liver disease (NAFLD) is the most common chronic liver disease and encompasses a spectrum of pathology from simple steatosis to inflammation and significant fibrosis that leads to cirrhosis. NAFLD and its comorbid conditions extend well beyond the liver. It is a multisystemic clinical disease entity with extrahepatic manifestations such as cardiovascular disease, type 2 diabetes, chronic kidney disease, hypothyroidism, polycystic ovarian syndrome, and psoriasis. Indeed, the most common causes of mortality in subjects with NAFLD are cardiovascular disease, followed by malignancies and then liver-related complications as a distant third. This review focuses on several of the key extrahepatic manifestations of NAFLD and areas for future investigation. Clinicians should learn to screen and initiate treatment for these extrahepatic manifestations in a prompt and timely fashion before they progress to end-organ damage.

Aerobic Exercise in the Management of Metabolic Dysfunction Associated Fatty Liver Disease

Sedentarism is the pandemic of modern times. It is associated with several medical conditions including obesity, type 2 diabetes mellitus, cardiovascular diseases and also liver disease, particularly metabolic dysfunction associated fatty liver disease (MAFLD). In an era when MAFLD is the most prevalent chronic liver disease worldwide, whilst no pharmacological therapy has been approved for it, exercise has proved to be effective in improving liver steatosis. Interestingly, exercise decreases liver fat even in the absence of weight loss. The challenge for the clinician is to motivate the obese patient with MAFLD, and associated co-morbidities, who has crystallized a sedentary behavior, at times when every need is at the distance of a click on the Internet, and the entire world can be visited behind a screen. In this review, the aggregate evidence on the mechanisms and effects of exercise in the management of MAFLD is summarized, with simple recommendations for everyday clinical practice.

Current treatment paradigms and emerging therapies for NAFLD/NASH

Non-alcoholic fatty liver disease (NAFLD) is one the fastest emerging manifestations of the metabolic syndrome worldwide. Non-alcoholic steatohepatitis (NASH), the progressive form of NAFLD, may culminate into cirrhosis and hepatocellular cancer (HCC) and is presently a leading cause of liver transplant. Although a steady progress is seen in understanding of the disease epidemiology, pathogenesis and identifying therapeutic targets, the slowest advancement is seen in the therapeutic field. Currently, there is no FDA approved therapy for this disease and appropriate therapeutic targets are urgently warranted. In this review we discuss the role of lifestyle intervention, pharmacological agents, surgical approaches, and gut microbiome, with regard to therapy for NASH. In particular, we focus the role of insulin sensitizers, thyroid hormone mimetics, antioxidants, cholesterol lowering drugs, incretins and cytokines as therapeutic targets for NASH. We highlight these targets aiming to optimize the future for NASH therapy.

Physical Activity and Low Glycemic Index Mediterranean Diet: Main and Modification Effects on NAFLD Score. Results from a Randomized Clinical Trial

Background: Non-Alcoholic Fatty Liver Disease (NAFLD) is the most common chronic liver disease worldwide, and lifestyle modification is the current standard treatment. The aim of the study was to estimate the effect of two different physical activity (PA) programs, a Low Glycemic Index Mediterranean Diet (LGIMD), and their combined effect on the NAFLD score as measured by FibroScan^®. Methods: Moderate or severe NAFLD subjects (n = 144) were randomly assigned to six intervention arms during three months. Interventions arms were a control diet, LGIMD, aerobic activity program (PA1), combined activity program (PA2), and LGIMD plus PA1 or LGIMD plus PA2. The data were compared at baseline, at 45 days, and at 90 days. Analysis of variance was performed under the intention-to-treat principle. Results: There was a statistically significant reduction in the NAFLD score after 45 days of treatment in every working arm except for Arm 1 (control diet). After 90 days, the best results were shown by the intervention arms in which LGIMD was associated with PA: LGIMD plus PA1 (−61.56 95% CI −89.61, −33.50) and LGIMD plus PA2 (−38.15 95% CI −64.53, −11.77). Conclusion: All treatments were effective to reduce NAFLD scores, but LGIMD plus PA1 was the most efficient.

Inadequate Physical Activity and Sedentary Behavior Are Independent Predictors of Nonalcoholic Fatty Liver Disease

BACKGROUND AND AIMS

In general, physical activity (PA) and nonalcoholic fatty liver disease (NAFLD) have an inverse association. However, studies assessing the impact of the widely accepted Physical Activity Guidelines for Americans (PA Guidelines) on NAFLD are lacking.

APPROACH AND RESULTS

We performed a serial, cross-sectional analysis among adults by using the 2007-2016 US National Health and Nutrition Examination Survey. NAFLD and advanced fibrosis were defined by using various noninvasive panels. A PA questionnaire assessed the leisure-time PA, occupation-related PA, transportation-related PA, and total sitting time as sedentary behavior. PA was categorized according to the PA Guidelines. Of the 24,588 individuals (mean age, 47.4 years; 47.9% males), leisure-time PA (≥150 minutes per week) demonstrated 40% lower odds of NAFLD, whereas transportation-related PA was associated with a 33% risk reduction in NAFLD. Analysis of total PA and sitting times simultaneously showed a dose-response association between sitting time and NAFLD (P for trend < 0.001). Compliance with the PA Guidelines was lower in individuals with NAFLD versus those without NAFLD. The trends in compliance with the PA Guidelines for any type of PA remained stable in individuals with NAFLD except for a downtrend in transportation-related PA. In contrast, an improvement in compliance with the PA Guidelines for leisure time was noted in the cohort without NAFLD. Although PA demonstrated a 10% stronger association with risk reduction of NAFLD in women, women showed a lower tendency of meeting the PA Guidelines. Trends in total sitting time increased significantly regardless of NAFLD status.

CONCLUSIONS

Sedentary behavior emerged as an independent predictor of NAFLD. Overall compliance with the PA Guidelines was lower in the cohort with NAFLD, with sex- and ethnicity-based differences. Implementation of these observations in clinical practice may improve our understanding as well as clinical outcomes.

Non-alcoholic fatty liver disease in patients with psoriasis: therapeutic implications

Non-alcoholic fatty liver disease (NAFLD) is the most common liver pathology in the western countries. Psoriatic patients are at higher risk of having NAFLD, and at higher risk of experiencing a more severe form of the disease with poorer outcomes. The components of the metabolic syndrome - obesity, lipid abnormalities, hypertension, and type 2 diabetes - significantly correlate with NAFLD progression. The inflammatory state present in psoriasis plays a significant role in development of NAFLD and the metabolic syndrome. All patients with psoriasis and insulin resistance and risk factors for metabolic syndrome should also been screened for NAFLD, and planning of the treatment options should always take into consideration the possible risks related to the liver, especially in patients with NAFLD.

Exercise Combats Hepatic Steatosis: Potential Mechanisms and Clinical Implications

Hepatic steatosis, the excess storage of intrahepatic lipids, is a rampant clinical problem associated with the obesity epidemic. Hepatic steatosis is linked to increased risk for insulin resistance, type 2 diabetes, and cardiovascular and advanced liver disease. Accumulating evidence shows that physical activity, exercise, and aerobic capacity have profound effects on regulating intrahepatic lipids and mediating susceptibility for hepatic steatosis. Moreover, exercise can effectively reduce hepatic steatosis independent of changes in body mass. In this perspective, we highlight 1) the relationship between obesity and metabolic pathways putatively driving hepatic steatosis compared with changes induced by exercise; 2) the impact of physical activity, exercise, and aerobic capacity compared with caloric restriction on regulating intrahepatic lipids and steatosis risk; 3) the effects of exercise training (modalities, volume, intensity) for treatment of hepatic steatosis, and 4) evidence for a sustained protection against steatosis induced by exercise. Overall, evidence clearly indicates that exercise powerfully regulates intrahepatic storage of fat and risk for steatosis.

Cholecystectomy does not worsen progression or outcomes in non-alcoholic fatty liver disease

Background

Cholecystectomy is a frequently performed surgical procedure for symptomatic cholelithiasis, which is reported to be more common in patients with non-alcoholic steatohepatitis (NASH), given the common risk factors. However, the data remains unclear on the association of cholecystectomy with NASH. We performed a retrospective study to examine the association of cholecystectomy and NASH.

Methods

Medical charts of patients with steatohepatitis related liver disease at a tertiary care center from 2004 to 2011 were stratified by cholecystectomy and defined by its history and/or absence of gallbladder on ultrasonography. Logistic regression model was built for predictors of cholecystectomy. Patients with NASH were stratified based on timing of cholecystectomy. The diagnosis of NASH and timing of cholecystectomy were compared based on baseline characteristics and outcomes (liver disease complications and survival) on follow up. Kaplan-Meier curves were generated for the two group comparisons. Chi-square and unpaired t-tests were used for comparing outcomes on follow up. P value <0.05 was considered significant.

Results

Analysis of 584 patients [379 non-alcoholic fatty liver disease (NAFLD)] showed that patients with cholecystectomy (N=191) were more likely to be female (57% vs. 44%), diabetic (53% vs. 37%), have liver biopsy (43% vs. 25%) and diagnosis of NAFLD (80% vs. 58%) P<0.001 for all. NAFLD diagnosis was associated with 2.79 folds odds of cholecystectomy. Among 379 (192 cholecystectomy) NAFLD patients, cirrhosis and female gender were associated with over 2 and 1.5 folds of cholecystectomy. Of 141 patients with data on timing of cholecystectomy, 55 (39%) with cholecystectomy at or after NAFLD diagnosis vs. 86 with cholecystectomy within median of 6 years prior to NAFLD diagnosis were similar on all characteristics except on model for end-stage liver disease (MELD) score (9.2±8.4 vs. 6.4±7.1, P=0.045). Of 28 with available histology data, there were no differences on histology based on timing of cholecystectomy. On a median follow up of 5 years, timing of cholecystectomy did not impact on development of cirrhosis (74% vs. 67%, P=0.45), ascites (31% vs. 38%, P=0.76), variceal bleeding (11% vs. 16%, P=0.44), hepatic encephalopathy (22% vs. 29%, P=0.74), hepatocellular carcinoma (HCC) (15% vs. 9%, P=0.59), and patient survival (95% vs. 98%, P=0.3).

Conclusions

Cholecystectomy is associated with NAFLD diagnosis. We did not find cause and effect of cholecystectomy in the development of severity of NAFLD. Prospective studies are suggested to examine the role of cholecystectomy and bile acids in the pathogenesis of NAFLD.

Physical exercise and liver "fitness": Role of mitochondrial function and epigenetics-related mechanisms in non-alcoholic fatty liver disease

BACKGROUND

Modern lifestyles, especially high-caloric intake and physical inactivity, contribute to the increased prevalence of non-alcoholic fatty liver disease (NAFLD), which becomes a significant health problem worldwide. Lifestyle changes, however, affect not only parental generation, but also their offspring, reinforcing the need for efficient preventive approaches to deal with this disease. This transgenerational influence of phenotypes dependent on parents (particularly maternal) behaviours may open additional research avenues. Despite persistent attempts to design an effective pharmacological therapy against NAFLD, physical activity, as a non-pharmacological approach, emerges as an exciting strategy.

SCOPE OF REVIEW

Here we briefly review the effect of physical exercise on liver mitochondria adaptations in NAFLD, highlighting the importance of mitochondrial metabolism and transgenerational and epigenetic mechanisms in liver diseases.

MAJOR CONCLUSIONS

A deeper look into cellular mechanisms sheds a light on possible effects of physical activity in the prevention and treatment of NAFLD through modulation of function and structure of particular organelles, namely mitochondria. Additionally, despite of increasing evidence regarding the contribution of epigenetic mechanisms in the pathogenesis of different diseases, the role of microRNAs, DNA methylation, and histone modification in NAFLD pathogenesis still needs to be elucidated.

Lifestyle modification in NAFLD/NASH: Facts and figures

The development of non-alcoholic fatty liver disease is closely linked to lifestyle factors, namely excessive caloric intake coupled with reduced physical activity and exercise. This review aims to examine the evidence behind lifestyle change as a tool to improve hepatic steatosis and liver histology in patients with non-alcoholic fatty liver disease/non-alcoholic steatohepatitis. Furthermore, potential barriers to adopting lifestyle changes and strategies to overcome these barriers in the clinical setting are discussed.

Independent Association of Physical Activity with Nonalcoholic Fatty Liver Disease and Alanine Aminotransferase Levels

The aim of the current study was to examine the independent association of physical activity with nonalcoholic fatty liver disease (NAFLD) and aminotransferases while adjusting for obesity and diet. Cross-sectional data from 32,391 participants aged ≥20 years in the Korea National Health and Nutrition Examination Surveys (KNHANES) was analyzed by logistic regression models and general linear models. Physical activity was assessed from the questionnaire by health-enhancing physical activity (HEPA). The physical activity was negatively associated with NAFLD and lean NAFLD after adjustment for multiple factors with an odds ratio of 0.7 (95% CI, 0.6–0.8) and 0.5 (95% CI, 0.4–0.7) comparing the most active (HEPA active) and the least active (inactive) participants. Among the participants with NAFLD, physical activity also showed an independent negative association with alanine aminotransferase (ALT) levels but not with aspartate aminotransferase levels. These independent associations were not observed when comparing the minimally active and inactive participants except for the risk of lean NAFLD. Physical activity is independently associated with the degree of hepatocellular injury in patients with NAFLD as well as the risk of NAFLD and lean NAFLD in the general population. Sufficiently active physical activity greater than a minimally active level may be needed to lower the risk of NAFLD and ALT levels.

Independent markers of nonalcoholic fatty liver disease in a gentrifying population-based Chinese cohort

BACKGROUND

Prevalence of nonalcoholic fatty liver disease (NAFLD) is increasing in developing countries, but its causes are not known. We aimed to ascertain the prevalence and determinants of NAFLD in a new largely unmedicated population-based cohort from the rapidly gentrifying region of Pinggu, China.

METHODS

We randomized cluster sampled 4002 Pinggu residents aged 26 to 76 years. Data from 1238 men and 1928 women without significant alcohol drinking or hepatitis virus B or C infection were analysed. NAFLD was defined using a liver-spleen ratio (L/S ratio) ≤1.1 on unenhanced abdominal computed tomography (CT) scanning.

RESULTS

Of men and women, 26.5% and 20.1%, respectively, had NAFLD. NAFLD prevalence was highest in younger men and older women. In multivariate logistic regression models, higher body mass index, waist circumference, serum triglyceride, alanine transaminase, and haemoglobin A1c independently increased the odds of NAFLD in both men and women separately. Higher annual household income and systolic blood pressure for men and higher serum uric acid and red meat intake and lower physical activity levels for women also independently associated with higher odds of NAFLD. Individuals with L/S ratio ≤1.1 had linearly increasing rates of obesity, diabetes, and metabolic syndrome that paralleled fatty liver increase.

CONCLUSIONS

NAFLD is common in a gentrifying Chinese population particularly in younger men of high socioeconomic status and older women with sedentary behaviour who eat red meat. Demographic factors add independent risk of NAFLD above traditional metabolic risk factors. A CT L/S ratio of ≤1.1 identifies individuals at high risk of metabolic disease.

Physical Activity, Fatty Liver, and Glucose Metabolism Over the Life Course: The Lifelines Cohort

OBJECTIVES

We examined the dose-dependent association of habitual moderate-to-vigorous physical activity (MVPA) with the biochemical markers for nonalcoholic fatty liver disease (NAFLD) and whether this association changes with age and degree of impaired glucose metabolism. We also investigated whether the associations depend on the domain of MVPA.

METHODS

In this study, using data from the population-based Lifelines cohort (N = 42,661), MVPA was self-reported on the short questionnaire to assess health-enhancing physical activity. NAFLD was defined as a fatty liver index value of >60, based on body mass index, waist circumference, plasma triglycerides, and gamma-glutamyltransferase. Glucose metabolism was defined as normal (NGM), impaired (IGM), and type 2 diabetes mellitus (T2DM). Exclusion criteria were previously diagnosed hepatitis or cirrhosis and excessive alcohol use. All analyses were adjusted for age, sex, and education.

RESULTS

Higher MVPA was dose dependently associated with a lower risk of having NAFLD: compared with "No MVPA," the odds ratios (ORs) (95% confidence intervals) for MVPA quintiles were 0.78 (0.71-0.86), 0.64 (0.58-0.70), 0.53 (0.48-0.59), 0.51 (0.46-0.56), and 0.45 (0.41-0.50) for the highest level of MVPA. The association between MVPA and NAFLD was stronger for more impaired glucose status (ORNGM = 0.49 (0.42-0.57), ORIGM = 0.46 (0.40-0.54), ORT2DM = 0.42 (0.27-0.66)) and for older age (OR20-40 years = 0.51 (0.42-0.62), OR60-80 years = 0.37 (0.29-0.48)) with the highest level of MVPA, relative to No MVPA. No favorable association was observed for occupational MVPA. With regard to MVPA and fibrosis, associations with fibrosis markers showed contradictory results.

CONCLUSIONS

Higher MVPA levels are dose dependently associated with a lower NAFLD risk. This association is stronger in people with diabetes and older adults.

From sugar to liver fat and public health: systems biology driven studies in understanding non-alcoholic fatty liver disease pathogenesis

Non-alcoholic fatty liver disease (NAFLD) is now a major public health concern with an estimated prevalence of 25-30% of adults in many countries. Strongly associated with obesity and the metabolic syndrome, the pathogenesis of NAFLD is dependent on complex interactions between genetic and environmental factors that are not completely understood. Weight loss through diet and lifestyle modification underpins clinical management; however, the roles of individual dietary nutrients (e.g. saturated and n-3 fatty acids; fructose, vitamin D, vitamin E) in the pathogenesis or treatment of NAFLD are only partially understood. Systems biology offers valuable interdisciplinary methods that are arguably ideal for application to the studying of chronic diseases such as NAFLD, and the roles of nutrition and diet in their molecular pathogenesis. Although present in silico models are incomplete, computational tools are rapidly evolving and human metabolism can now be simulated at the genome scale. This paper will review NAFLD and its pathogenesis, including the roles of genetics and nutrition in the development and progression of disease. In addition, the paper introduces the concept of systems biology and reviews recent work utilising genome-scale metabolic networks and developing multi-scale models of liver metabolism relevant to NAFLD. A future is envisioned where individual genetic, proteomic and metabolomic information can be integrated computationally with clinical data, yielding mechanistic insight into the pathogenesis of chronic diseases such as NAFLD, and informing personalised nutrition and stratified medicine approaches for improving prognosis.

Comprehensive lifestyle intervention vs soy protein-based meal regimen in non-alcoholic steatohepatitis

BACKGROUND

Non-alcoholic steatohepatitis (NASH) has become one of the leading causes of liver disease in the western world. In obese patients weight reduction is recommended. Up to now there are no specific guidelines for weight loss in order to reduce hepatic fat content.

AIM

To investigate the effects of a 24-wk guided lifestyle intervention program compared to a meal replacement regimen based on soy protein.

METHODS

Twenty-six subjects with NASH participated in a randomized single-center study. They were randomly assigned to either meal replacement group (MR-G) with soy-yogurt-honey preparation or to guided lifestyle change group (LC-G) with endurance activity and nutrition counselling. Serum alanine transaminase (ALT), aspartate transaminase (AST), lipid parameters, and adipokines were measured. Liver fat content and lipid composition were determined by magnetic resonance imaging and magnetic resonance spectroscopy. Body fat mass and lean body mass were assessed using Bod Pod^® device. Pre- and post-intervention monitoring of parameters was performed. Statistical analyses were conducted with SPSS software, results were expressed as median (interquartile range).

RESULTS

Twenty-two subjects (MR-G, n = 11 and LC-G, n = 11) completed the study (9 women, 13 men; age 52.1 (15.0) years, body mass index (BMI) 32.3 (3.3) kg/m²). In both groups a significant weight loss was achieved (MR-G: -6.4 (3.6) kg, P < 0.01; LC-G: -9.1 (10.4) kg, P < 0.01). BMI dropped in both groups (MR-G: -2.3 (1.5) kg/m², P = 0.003; LC-G: -3.0 (3.4) kg/m², P = 0.006). Internal fat and hepatic lipid content were markedly reduced in both groups in comparable amount. There was a strong correlation between reduction in liver fat and decrease in ALT. Likewise, both groups showed an improvement in glycemic control and lipid profile. Changes in adipokines, particularly in adiponectin and leptin were closely related to intrahepatic lipid changes.

CONCLUSION

Comprehensive lifestyle intervention and meal replacement regimen have comparable effects on body and liver fat, as well as decrease in markers of hepatic inflammation among NASH patients.

A randomized controlled trial on the effectiveness of 8-week high-intensity interval exercise on intrahepatic triglycerides, visceral lipids, and health-related quality of life in diabetic obese patients with nonalcoholic fatty liver disease

BACKGROUND

Medications are limited for patients with nonalcoholic fatty liver disease (NAFLD). It has been reported that aerobic exercise is effective in reducing the characteristics of NAFLD, although unclear data have ascertained the effects of high-intensity interval aerobic exercise on health-related quality of life (HRQoL) in diabetic obese patients with NAFLD.

OBJECTIVES

This a randomized controlled trial aimed to ascertain the effectiveness of 8-week high-intensity interval exercise on intrahepatic triglycerides (IHTG), visceral lipids and HRQoL in diabetic obese patients with NAFLD.

STUDY DESIGN

Between August and December 2017, 32 diabetic obese patients with NAFLD aged 45 to 60 years (21 men and 11 women) were enrolled in this study. They were randomly assigned to 2 groups, 16 patients in each group, high-intensity interval (HII) exercise and control groups. The HII group received a program of HII aerobic exercise for 8 weeks with medications of NAFLD and the control group received only medications without any type of exercise intervention. The test of IHTG, visceral lipids, and HRQoL were recorded at the initial assessment and at the end of the program after 8 weeks.

RESULTS

There were significant differences between the 2 groups at the end of the study. These study findings exhibited significant improvements in IHTG, VO2peak, visceral lipids, glycohemoglobin, plasma glucose, and all dimensions of HRQoL in the HII group (P <.05), But there was non-significant improvement in any measure in the control group (P >.05) after the 8-week intervention.

CONCLUSION

Eight-week high-intensity interval aerobic exercise has a beneficial effect on IHTG, visceral lipids, and HRQoL in diabetic obese patients with NAFLD. Effort and awareness should be dedicated to encouraging the active lifestyle among different population, especially diabetic obese patients with NAFLD.

Nutrition and physical activity in Asian Indians with non-alcoholic fatty liver: A case control study

AIM

We tested the hypothesis that Asian Indians with non-alcoholic fatty liver disease (NAFLD) would have imbalanced diets and lower intensity of physical activity than those without NAFLD.

METHODS

We studied dietary intake, intensity of physical activity and anthropometric and metabolic profiles in subjects with NAFLD and in healthy controls. Complete clinical, biochemical, dietary and physical activity profiles were studied for 169 cases and 173 controls in a prospective manner. Bivariate and multivariate analyses were carried out to identify the predictors of NAFLD [odds ratio (OR) and 95% confidence intervals (95%CI)].

RESULTS

The mean dietary intakes of total energy, carbohydrate, protein, total fat, saturated fat and total cholesterol were significantly higher, while intake of monounsaturated fatty acids and polyunsaturated fatty acids was significantly lower in cases as compared to controls (p < 0.01 for all). Further, mean physical activity in a day (expressed as MET.Minutes) and total energy expenditure were significantly lower in cases than in controls (33.3 ± 3.6 vs.36.2 ± 0.5, p = 0.001 and 2707.6 ± 505.6 vs. 2904.3 ± 690.3, p = 0.02, respectively). On multivariate analysis, percentage dietary total fat intake (OR: 13.4; 95% CI: 4.6-39.3, p = 0.001), homeostatis model assessment for insulin resistance (OR: 6.9; 95% CI: 3.2-14.8, p = 0.001) abdominal obesity (OR: 2.7; 95% CI: 1.5-5.0, p = 0.001) and high serum triglycerides (OR: 2.1; 95%CI: 1.2-3.8, p = 0.007) were associated with an increased risk for development of NAFLD.

CONCLUSION

Decrease in intake of total dietary fats and improvement of insulin resistance, abdominal obesity and blood triglycerides should be important measures for management of NAFLD in Asian Indians in north India.