Nonoverweight nonalcoholic fatty liver disease and incident cardiovascular disease: A post hoc analysis of a cohort study

Coronary Artery Disease and Major Adverse Cardiovascular Events in People With Hepatic Steatosis at Low Atherosclerotic Cardiovascular Disease Risk

BACKGROUND

Hepatic steatosis (HS) and 10-year atherosclerotic cardiovascular disease (ASCVD) risk ≥ 7.5% are associated with increased risk for cardiovascular events.

AIM

To assess underlying coronary artery disease (CAD) and major adverse cardiovascular event (MACE) among those with and without HS at different ASCVD risk.

METHODS

We evaluated stable chest pain patients receiving coronary computed tomography (CT) in the PROMISE trial. HS and CAD endpoints were defined on coronary CT. MACE was defined as unstable angina, non-fatal myocardial infarction, and all-cause death. Multivariable Cox regression, adjusting for CAD characteristics, assessed the association of HS with MACE for ASCVD < 7.5%.

RESULTS

One thousand two hundred and four of 3702 (32.5%) patients were at ASCVD < 7.5% and 20.3% (244/1204) of them had HS. Individuals with HS were younger (54.3 ± 5.2 vs. 55.8 ± 5.2; p < 0.001), more often males (40.2% [98/244] vs. 27.1% [260/960]; p < 0.001), had more risk factors/person (2.06 ± 0.89 vs. 1.93 ± 0.91; p = 0.047). CAD characteristics were similar between HS vs. non-HS patients at ASCVD < 7.5% and ASCVD ≥ 7.5% (all p > 0.05). Patients with HS had greater MACE rate compared to non-HS patients (ASCVD < 7.5%: 3.75%[9/244] vs. 1.5% [14/960]; p = 0.027 and ASCVD ≥ 7.5%: 4.7% [33/696] vs. 3.1% [56/1802]; p = 0.043). In patients without HS, MACE rate was higher in the ASCVD ≥ 7.5% vs. < 7.5% (3.1% [56/1802] vs. 1.5% [14/960]; p = 0.011). In patients with HS, MACE rates were not significantly different between ASCVD ≥ 7.5% vs. < 7.5% (4.7% [33/696] vs. 3.7% [9/244]; p = 0.484). In ASCVD < 7.5%, HS predicted MACE (aHR:2.34, 95%CI:1.01-5.43; p = 0.048), independent of CAD characteristics.

CONCLUSIONS

Individuals with HS at ASCVD < 7.5% risk had similar CAD characteristics as patients without HS at < 7.5% ASCVD risk, yet experienced comparable MACE rates as those at ASCVD ≥ 7.5%.

Mortality, Hepatic Decompensation, and Cardiovascular Outcomes in Lean vs. Non-lean MASLD Cirrhosis: A Veterans Affairs Cohort Study

BACKGROUND AND AIMS

Metabolic dysfunction-associated steatotic liver disease (MASLD) has a global prevalence of 25%. Studies on incident liver and cardiovascular outcomes in lean (Body mass index: BMI < 25 kg/m2, or < 23 kg/m2 for Asians) vs. non-lean individuals with MASLD have reported mixed results. We aimed to compare incident clinical outcomes and mortality between lean and non-lean individuals with compensated MASLD cirrhosis in a large national cohort.

METHODS

This was a retrospective cohort study of patients with newly diagnosed compensated MASLD cirrhosis in the Veterans Health Administration between 01/2008 and 05/2021. The primary outcome was incident hepatic decompensation, and secondary outcomes were incident major adverse cardiovascular events (MACE) and all-cause mortality. Multivariable Cox proportional hazard models were used to assess association. Fine and Gray competing risk regression was used where applicable.

RESULTS

The study included 15155 patients with MASLD cirrhosis: 1,597 lean and 13558 non-lean patients. Included patients were mostly male (95%), median age was 67 years, and 72.8% were non-Hispanic white. At baseline, the prevalence of diabetes was lower in lean vs. non-lean individuals (46.7 vs. 73.9%, p < 0.001). In multivariable models, lean status was associated with a 64% increased risk of all-cause mortality (aHR = 1.64) but decreased risk of hepatic decompensation (aSHR = 0.67). Lean individuals experienced significantly higher rates of cardiovascular-related mortality (aHR = 1.40).

CONCLUSION

Lean MASLD patients with compensated cirrhosis had a higher mortality risk but a lower risk of hepatic decompensation than non-lean patients. Despite having a better baseline cardiometabolic profile and similar rates of MACE, lean individuals with MASLD cirrhosis have a higher risk of cardiovascular mortality.

[Triglyceride-glucose index in non-obese individuals: its association with and predictive value for non-alcoholic fatty liver disease]

OBJECTIVE

To investigate the association of triglyceride-glucose index (TyG) with non-alcoholic fatty liver disease (NAFLD) and its diagnostic value for NAFLD in non-obese individuals.

METHODS

We retrospectively collected the data of non-obese individuals (BMI < 25 kg/m2) undergoing routine health examination at Second Affiliated Hospital of Xi'an Jiaotong University between May, 2020 and December, 2023, who all received abdominal ultrasound examination for NAFLD screening. The nonlinear relationship between TyG and non-obese NAFLD was explored using restricted cubic splines (RCS), and LASSO regression was used for variable screening; the correlation between TyG and NAFLD risk was analyzed using multivariate logistic regression. The diagnostic value of TyG for non-obese NAFLD was assessed using receiver-operating characteristic (ROC) curves and sensitivity analysis.

RESULTS

A total of 3723 non-obese subjects were enrolled in this study, including 432 (11.6%) patients with NAFLD. Compared with the healthy individuals, the patients with NAFLD had significant elevations of systolic and diastolic blood pressures, total cholesterol, triglycerides, LDL-C, blood uric acid, fasting blood glucose, and TyG index and a decreased HDL-C level (P < 0.05). Multivariate logistic regression revealed that for each one-unit increase of TyG, the risk of non-obese NAFLD increased by 2.2 folds (OR=3.22, 95% CI: 2.53-4.12, P < 0.001). Compared with a TyG index in the lowest quartile Q1, a TyG index in the Q2, Q3 and Q4 quartiles was associated with an increased risk of NAFLD by 1.52 folds (OR=2.52, 95% CI: 1.20-5.95), 3.56 folds (OR=4.56, 95% CI: 2.28-10.46), and 8.66-folds (OR=9.66, 95% CI: 4.83-22.18), respectively. The RCS curve demonstrated a significant linear correlation between TyG index and non-obese NALFD risk (P for nonlinear= 0.019). For diagnosing non-obese NALFD, TyG index had an area under ROC curve of 0.819 with a sensitivity of 78.0% and a specificity of 71.2%.

CONCLUSION

An increase of TyG index is correlated with increased risks of NAFLD in non-obese individuals and can serve as an indicator for screening early NAFLD in healthy individuals.

Triglyceride glucose index as a predictor for non-alcoholic fatty liver disease: insights from a longitudinal analysis in non-obese individuals

Background

A substantial portion of non-obese population is afflicted with Non-alcoholic Fatty Liver Disease (NAFLD). The Triglyceride Glucose (TyG) index, a quantifier of insulin resistance magnitude, is determined by the product of fasting plasma glucose and triglyceride concentrations. The relationship between the TyG index and NAFLD within this cohort remains ambiguous.

Methods

We conducted a retrospective analysis utilizing datasets acquired from the Dryad digital repository. Non-obese participants (BMI < 25 kg/m2) were enrolled at the Wenzhou Medical Center of Wenzhou People's Hospital between January 2010 and December 2014. Demographic information and biochemical parameters were systematically compiled, and the diagnosis of NAFLD was established through ultrasonographic evidence.

Results

This study cohort included 16,172 non-obese participants with a 5-year follow-up, among whom 2,322 (14.36%) developed NAFLD. The disparity between TyG index quartiles in the accumulative incidence of new-onset NAFLD was distinct, with an increasing risk of new-onset NAFLD as the TyG index increased. Participants in highest quartile exhibited the maximum risk of NAFLD. In the fully adjusted model 3, the hazard ratios for NAFLD in Q2, Q3, and Q4 were 2.15 (1.62, 2.87), 2.89 (2.20, 3.80) and 4.58 (3.48, 6.02), respectively. Meanwhile, the TyG index and NAFLD risk showed a highly significant overall correlation (p < 0.0001) and nonlinearity (p < 0.0001) according to the limited cubic splines. In subgroup analysis, a significant interaction was noted between new-onset NAFLD and SBP (<140 mmHg vs. ≥140 mmHg; P for interaction = 0.0114). The SBP < 140 mmHg subgroup demonstrated an enhanced TyG index influence on NAFLD risk (HR = 2.83, 95% CI: 2.48-3.23, p < 0.0001).

Conclusion

The TyG index serves as a straightforward instrument for assessing NAFLD risk in non-obese individuals, enabling prompt identification and management in this population segment.

A novel bioinformatics strategy to uncover the active ingredients and molecular mechanisms of Bai Shao in the treatment of non-alcoholic fatty liver disease

Introduction: As a new discipline, network pharmacology has been widely used to disclose the material basis and mechanism of Traditional Chinese Medicine in recent years. However, numerous researches indicated that the material basis of TCMs identified based on network pharmacology was the mixtures of beneficial and harmful substances rather than the real material basis. In this work, taking the anti-NAFLD (non-alcoholic fatty liver disease) effect of Bai Shao (BS) as a case, we attempted to propose a novel bioinformatics strategy to uncover the material basis and mechanism of TCMs in a precise manner. Methods: In our previous studies, we have done a lot work to explore TCM-induced hepatoprotection. Here, by integrating our previous studies, we developed a novel computational pharmacology method to identify hepatoprotective ingredients from TCMs. Then the developed method was used to discover the material basis and mechanism of Bai Shao against Non-alcoholic fatty liver disease by combining with the techniques of molecular network, microarray data analysis, molecular docking, and molecular dynamics simulation. Finally, literature verification method was utilized to validate the findings. Results: A total of 12 ingredients were found to be associated with the anti-NAFLD effect of BS, including monoterpene glucosides, flavonoids, triterpenes, and phenolic acids. Further analysis found that IL1-β, IL6, and JUN would be the key targets. Interestingly, molecular docking and molecular dynamics simulation analysis showed that there indeed existed strong and stable binding affinity between the active ingredients and the key targets. In addition, a total of 23 NAFLD-related KEGG pathways were enriched. The major biological processes involved by these pathways including inflammation, apoptosis, lipid metabolism, and glucose metabolism. Of note, there was a great deal of evidence available in the literature to support the findings mentioned above, indicating that our method was reliable. Discussion: In summary, the contributions of this work can be summarized as two aspects as follows. Firstly, we systematically elucidated the material basis and mechanism of BS against NAFLD from multiple perspectives. These findings further enhanced the theoretical foundation of BS on NAFLD. Secondly, a novel computational pharmacology research strategy was proposed, which would assist network pharmacology to uncover the scientific connotation TCMs in a more precise manner.

Cardiovascular morbidity and mortality in lean vs. non-lean MASLD: A comprehensive meta-analysis

BACKGROUND

Lean metabolic dysfunction-associated steatotic liver disease (MASLD), characterized by a BMI < 25 kg/m² (or < 23 kg/m² in Asians), presents a challenging prognosis compared to non-lean MASLD. This study examines cardiovascular outcomes in both lean and non-lean MASLD cohorts.

METHODS

In this meta-analysis, pooled odds ratios (ORs) within 95 % confidence intervals (CIs) were calculated for primary outcomes (cardiovascular mortality and major adverse cardiovascular events [MACE]) and secondary outcomes (cardiovascular disease [CVD], all-cause mortality, hypertension, and dyslipidemia). Studies comparing lean and non-lean MASLD within the same cohorts were analyzed, prioritizing those with larger sample sizes or recent publication dates.

RESULTS

Twenty-one studies were identified, encompassing lean MASLD patients (n = 7153; mean age 52.9 ± 7.4; 56 % male) and non-lean MASLD patients (n = 23,514; mean age 53.2 ± 6.8; 63 % male). Lean MASLD exhibited a 50 % increase in cardiovascular mortality odds compared to non-lean MASLD (OR: 1.5, 95 % CI 1.2-1.8; p < 0.0001). MACE odds were 10 % lower in lean MASLD (OR: 0.9, 95 % CI 0.7-1.2; p = 0.7), while CVD odds were 40 % lower (p = 0.01). All-cause mortality showed a 40 % higher odds in lean MASLD versus non-lean MASLD (p = 0.06). Lean MASLD had 30 % lower odds for both hypertension (p = 0.01) and dyslipidemia (p = 0.02) compared to non-lean MASLD.

CONCLUSION

Despite a favorable cardiometabolic profile and comparable MACE rates, lean individuals with MASLD face elevated cardiovascular mortality risk.

Cardiometabolic and Metabolic Profiles of Lean/Normal, Overweight and Obese Patients with Nonalcoholic Fatty Liver Disease

Purpose

Disagreements about the risk of non-obese, non-alcoholic fatty liver disease for cardiometabolic outcomes occurred widely. This study aims to characterize the cardiometabolic and metabolic profile of lean/normal, overweight and obese patients with nonalcoholic fatty liver disease on a big sample.

Patients and methods

Appeared healthy adults who participated in health examinations during the year of 2019-2022 were screened for fatty liver diagnosis. BMI classified fatty livers as lean, overweight and obese. Eleven cardiometabolic metrics (SBP: systolic blood pressure; DBP: diastolic blood pressure; TC: total cholesterol; TG: triglycerides; HDL: high-density lipoprotein cholesterol; LDL: low-density lipoprotein cholesterol) and metabolic metrics (GLU: blood glucose; GHB: glycated haemoglobin; UA: uric acid; AST: aspartate aminotransferase; ALT: alanine aminotransferase) were included, described and compared among BMI categories.

Results

There were 56,496 fatty livers diagnosed by ultrasound in this study. In total, the lean fatty liver had lowest mean SBP, DBP, GLU, TG, UA, AST, and ALT but highest TC and HDL among BMI categories (all p < 0.001). The number of abnormal metrics in total was 2.5, 2.9 and 3.4 in lean, overweight, and obesity, respectively (p < 0.001, p_trend < 0.001). Visualized data showed that lean fatty liver was similar but milder in all metabolic metrics than overweight and obesity at the young ages. However, lean fatty liver had higher coefficients of age and risk of metabolic abnormality regression (p <0.001 for SBP, DBP, GLU, GHB, TC).

Conclusion

The lean type of fatty livers at a younger age has a relatively favourable cardiometabolic and metabolic profile compared to overweight and obese fatty livers. Due to the possible catch-up effect of metabolic dysfunctions in young lean fatty liver, lean fatty liver may have the same health outcomes as overweight/obesity fatty liver in long term. The evaluation and intervention may be critical for young lean fatty liver management to slowdown the rapid progress of metabolic dysfunction.

Effects of weight loss on metabolic dysfunction-associated fatty liver disease in Japanese people: Non-alcoholic fatty liver disease in the Gifu area, longitudinal analysis study

AIM

Metabolic dysfunction-associated fatty liver disease (MAFLD) is a major health concern. This cohort study aimed to evaluate the association between weight loss and remission of MAFLD in the Japanese population to aid the development of efficient treatment strategies.

METHODS

This retrospective cohort study was conducted at a Japanese health screening center. Participants included 3309 individuals diagnosed with baseline MAFLD between 2004 and 2016. Logistic regression analysis was used to assess the association between MAFLD remission from baseline to 5 years and weight change.

RESULTS

After 5 years, 671 participants achieved MAFLD remission. Weight loss was associated with MAFLD remission for every 1 kg of weight loss over 5 years; the odds ratio for MAFLD remission was 1.24 (95% CI 1.15-1.34) for participants with type 2 diabetes, 1.40 (95% CI 1.35-1.45) for overweight participants, and 1.51 (95% CI 1.33-1.72) for non-overweight participants with metabolic dysfunctions. The cutoff values for weight loss for MAFLD remission were 1.9 kg for all participants, 3.0 kg for participants with type 2 diabetes, 1.9 kg for overweight participants, and 0.8 kg for non-overweight participants with metabolic dysfunctions.

CONCLUSIONS

Among participants diagnosed with MAFLD, weight loss was associated with MAFLD remission regardless of the type of metabolic dysfunction in MAFLD. The results of this study may contribute to the development of novel approaches to achieve MAFLD remission.

Association between alanine aminotransferase to high-density lipoprotein cholesterol ratio and nonalcoholic fatty liver disease: a retrospective cohort study in lean Chinese individuals

There is limited research on the association between the alanine aminotransferase to high-density lipoprotein cholesterol ratio (ALT/HDL-C) ratio and nonalcoholic fatty liver disease (NAFLD). The purpose of the current research was to look into the connection between the ALT/HDL-C ratio and the risk of NAFLD in lean Chinese individuals. Between January 2010 and December 2014, 11,975 non-obese people participated in this prospective cohort research. The relationship between the ALT/HDL-C ratio and the risk of developing NAFLD was assessed using the Cox proportional-hazards regression model, Cox proportional hazards regression with cubic spline functions and smooth curve fitting, sensitivity analysis, and subgroup analyses. The ALT/HDL-C ratio's potential value as a NAFLD prognostic marker was to be evaluated using the receiver operating characteristic curve analysis. A total of 5419 (45.253%) women comprised the research's participant population, and the research participants' average age was 43.278 ± 14.941 years. The ALT/HDL-C ratio was 11.607 (7.973-17.422) at the median (interquartile ranges). 2087 (17.428%) patients had NAFLD diagnoses throughout a median follow-up of 24.967 months. The study's findings demonstrated a positive connection between the ALT/AHDL-C ratio and the incident NAFLD (HR = 1.037, 95% CI: 1.031-1.042) when adjusting for relevant factors. The ALT/HDL-C ratio and NAFLD risk had a nonlinear connection, with 12.963 as the ratio's inflection point. Effect sizes (HR) were 1.023 (95% CI: 1.017-1.029) and 1.204 (95% CI: 1.171-1.237), respectively, on the right and left sides of the inflection point. The sensitivity analysis also showed how reliable our findings were. According to subgroup analysis, those with BMI < 24 kg/m2 and DBP < 90 mmHg had a stronger correlation between the ALT/HDL-C ratio and NAFLD risk. The current study shows a positive and non-linear connection between the ALT/HDL-C ratio and NAFLD risk in lean Chinese individuals. When the ALT/HDL-C ratio is less than 12.963, it is significantly linked to NAFLD. Therefore, from a therapy standpoint, it is advised to keep the ALT/HDL-C ratio less than the inflection point.

Longitudinal Outcomes Associated With Metabolic Dysfunction-Associated Steatotic Liver Disease: A Meta-analysis of 129 Studies

BACKGROUND & AIMS

The progression of metabolic dysfunction-associated steatotic liver disease (MASLD) has been found to manifest in a series of hepatic and extrahepatic complications. A comprehensive meta-analysis of the longitudinal outcomes associated with MASLD has yet to be conducted.

METHODS

To investigate the longitudinal outcomes associated with MASLD, Medline and Embase databases were searched to identify original studies that evaluated the longitudinal risks of incident clinical outcomes among MASLD patients compared with non-MASLD individuals. DerSimonian Laird random-effects meta-analysis was performed. Pooled effect estimates were calculated, and heterogeneity among studies was evaluated.

RESULTS

One hundred twenty-nine studies were included in the meta-analysis. Meta-analysis revealed a significant increase in the risk of cardiovascular outcomes (hazard ratio [HR], 1.43; 95% confidence interval [CI], 1.27-1.60; P < .01), various metabolic outcomes such as incident hypertension (HR, 1.75; 95% CI, 1.46-2.08; P < .01), diabetes (HR, 2.56; 95% CI, 2.10-3.13; P < .01), pre-diabetes (HR, 1.69; 95% CI, 1.22-2.35; P < .01), metabolic syndrome (HR, 2.57; 95% CI, 1.13-5.85; P = .02), chronic kidney disease (HR, 1.38; 95% CI, 1.27-1.50; P < .01), as well as all cancers (HR, 1.54; 95% CI, 1.35-1.76; P < .01) among MASLD patients compared with non-MASLD individuals. By subgroup analysis, MASLD patients with advanced liver disease (HR, 3.60; 95% CI, 2.10-6.18; P < .01) were also found to be associated with a significantly greater risk (P = .02) of incident diabetes than those with less severe MASLD (HR, 1.63; 95% CI, 1.0-2.45; P = .02) when compared with non-MASLD.

CONCLUSIONS

The present study emphasizes the association between MASLD and its clinical outcomes including cardiovascular, metabolic, oncologic, and other outcomes. The multisystemic nature of MASLD found in this analysis requires treatment targets to reduce systemic events and end organ complications.

Clinical correlates of CT imaging-derived phenotypes among lean and overweight patients with hepatic steatosis

The objective of this study is to define CT imaging derived phenotypes for patients with hepatic steatosis, a common metabolic liver condition, and determine its association with patient data from a medical biobank. There is a need to further characterize hepatic steatosis in lean patients, as its epidemiology may differ from that in overweight patients. A deep learning method determined the spleen-hepatic attenuation difference (SHAD) in Hounsfield Units (HU) on abdominal CT scans as a quantitative measure of hepatic steatosis. The patient cohort was stratified by BMI with a threshold of 25 kg/m2 and hepatic steatosis with threshold SHAD ≥  - 1 HU or liver mean attenuation ≤ 40 HU. Patient characteristics, diagnoses, and laboratory results representing metabolism and liver function were investigated. A phenome-wide association study (PheWAS) was performed for the statistical interaction between SHAD and the binary characteristic LEAN. The cohort contained 8914 patients-lean patients with (N = 278, 3.1%) and without (N = 1867, 20.9%) steatosis, and overweight patients with (N = 1863, 20.9%) and without (N = 4906, 55.0%) steatosis. Among all lean patients, those with steatosis had increased rates of cardiovascular disease (41.7 vs 27.8%), hypertension (86.7 vs 49.8%), and type 2 diabetes mellitus (29.1 vs 15.7%) (all p < 0.0001). Ten phenotypes were significant in the PheWAS, including chronic kidney disease, renal failure, and cardiovascular disease. Hepatic steatosis was found to be associated with cardiovascular, kidney, and metabolic conditions, separate from overweight BMI.

What Does Sarcopenia Have to Do with Nonalcoholic Fatty Liver Disease?

Nonalcoholic fatty liver disease (NAFLD) is one of the most common causes of chronic liver disease. As the second stage of developing steatosis, nonalcoholic hepatitis (NASH) carries the risk of fibrosis, cirrhosis, and hepatocellular carcinoma. Sarcopenia is defined as a condition characterized by a decrease in muscle mass and functional decline. Both NAFLD and sarcopenia are global problems. The pathophysiological mechanisms that link the two entities of the disease are insulin resistance, inflammation, nutritional deficiencies, impairment of myostatin and adiponectin, or physical inactivity. Furthermore, disorders of the gut-liver axis appear to induce the process of developing NAFLD and sarcopenia. The correlations between NAFLD and sarcopenia appear to be bidirectional, so the main objective of the review was to determine the cause-and-effect relationship between the two diseases.

Corrected and republished from: Metabolic associated liver disease

Alcohol consumption (AC) and metabolic syndrome (MS) represent the first cause of liver disease, hepatocellular carcinoma and liver transplantation. The habit of consuming alcoholic beverages and the presence of MS and non-alcoholic fatty liver disease (NAFLD) often coexist in the same patient. The histoclinical boundaries between alcohol related liver disease (ALD) and NAFLD are often not well defined. The co-presence of AC and MS increases the risk of hepatic and extra-hepatic disease. The terminological evolution from NAFLD to metabolic associated fatty liver disease (MAFLD) is certainly a useful advance. However, it is known that the appearance of liver fibrosis increases oncologic and cardiovascular disease risk, which in the case of cirrhosis can be present even in the absence of steatosis and that the mechanisms of fibrogenesis can act independently of the presence of steatosis/steatohepatitis. For this reason, as already stated recently, a further terminological evolution can be hypothesized. This article was originally published with mistakes in the text. The new corrected citable version appears below.

Application of noninvasive test (acoustic attenuation imaging and ultrasonic shear wave elastography) to grade nonalcoholic fatty liver disease: An observational study

The aim of this study was to validate the diagnostic efficacy of acoustic attenuation imaging (ATI) and ultrasonic shear wave elastography (SWE) in classifying nonalcoholic fatty liver disease (NAFLD). A total of 100 patients with NAFLD were recruited from our hospital between January 2021 and December 2022. Patient demographics and clinical data were collected, and 2-dimensional ultrasound was used to screen patients based on liver echo characteristics. Patients without liver space-occupying lesions underwent routine ultrasound examinations. Imaging or serology was used to confirm the presence of fatty liver in patients or healthy individuals. Patients with alcoholic liver disease (alcohol equivalent content < 20 g/day for women, <30 g/day for men), as well as those with lenticular degeneration, total parenteral nutrition, autoimmune liver disease, drug-induced hepatitis, and viral hepatitis, were excluded from the study. Out of the 100 included patients, 24 had normal liver, 21 had mild fatty liver, 30 had moderate fatty liver, and 25 had severe fatty liver. There were age differences between the normal group and patients with mild fatty liver, and the average body mass index (BMI) varied across the 4 groups. As the severity of the disease increased, the average BMI also increased (P < .05). The ATI scores and SWE scores differed significantly among the different groups (P < .05), with both scores showing an upward trend as the fatty liver condition worsened. Correlation analysis revealed positive correlations between ATI and SWE scores and the degree of fatty liver (P < .05), positive correlations with BMI (P < .05), and negative correlations with high-density lipoprotein cholesterol expression (P < .05). The area under the curve (AUC) for the ATI score in diagnosing different degrees of fatty liver was > 0.750, and the AUC for the SWE score was also > 0.750. The AUC for SWE score in diagnosing different degrees of fatty liver ranged from 1.01 to 4.57, while the combined AUC for ATI and SWE scores was > 0.850, with respective cutoff values of 3.62, 5.72, and 7.57 based on the maximum approximate entry index. The combination of ATI and SWE has a significant impact on the grading diagnosis of NAFLD, and its application can be extended to clinical practice.

Mechanisms Linking Metabolic-Associated Fatty Liver Disease (MAFLD) to Cardiovascular Disease

PURPOSE OF REVIEW

Metabolic-associated fatty liver disease (MAFLD) is a condition of fat accumulation in the liver that occurs in the majority of patients in combination with metabolic dysfunction in the form of overweight or obesity. In this review, we highlight the cardiovascular complications in MAFLD patients as well as some potential mechanisms linking MAFLD to the development of cardiovascular disease and highlight potential therapeutic approaches to treating cardiovascular diseases in patients with MAFLD.

RECENT FINDINGS

MAFLD is associated with an increased risk of cardiovascular diseases (CVD), including hypertension, atherosclerosis, cardiomyopathies, and chronic kidney disease. While clinical data have demonstrated the link between MAFLD and the increased risk of CVD development, the mechanisms responsible for this increased risk remain unknown. MAFLD can contribute to CVD through several mechanisms including its association with obesity and diabetes, increased levels of inflammation, and oxidative stress, as well as alterations in hepatic metabolites and hepatokines. Therapies to potentially treat MAFLD-induced include statins and lipid-lowering drugs, glucose-lowering agents, antihypertensive drugs, and antioxidant therapy.

Fibrotic Burden in the Liver Differs Across Metabolic Dysfunction-Associated Fatty Liver Disease Subtypes

Background/Aims

Metabolic dysfunction-associated fatty liver disease (MAFLD) is categorized into three subtypes: overweight/obese (OW), lean/normal weight with metabolic abnormalities, and diabetes mellitus (DM). We investigated whether fibrotic burden in liver differs across subtypes of MAFLD patients.

Methods

This cross-sectional multicenter study was done in cohorts of subjects who underwent a comprehensive medical health checkup between January 2014 and December 2020. A total of 42,651 patients with ultrasound-diagnosed fatty liver were included. Patients were classified as no MAFLD, OW-MAFLD, lean-MAFLD, and DM-MAFLD. Advanced liver fibrosis was defined based on the nonalcoholic fatty liver disease fibrosis score (NFS) or fibrosis-4 (FIB-4) index.

Results

The mean age of the patients was 50.0 years, and 74.1% were male. The proportion of patients with NFS-defined advanced liver fibrosis was the highest in DM-MAFLD (6.6%), followed by OW-MAFLD (2.0%), lean-MAFLD (1.3%), and no MAFLD (0.2%). The proportion of patients with FIB-4-defined advanced liver fibrosis was the highest in DM-MAFLD (8.6%), followed by lean-MAFLD (3.9%), OW-MAFLD (3.0%), and no MAFLD (2.0%). With the no MAFLD group as reference, the adjusted odds ratios (95% confidence intervals) for NFS-defined advanced liver fibrosis were 4.46 (2.09 to 9.51), 2.81 (1.12 to 6.39), and 9.52 (4.46 to 20.36) in OW-MAFLD, lean-MAFLD, and DM-MAFLD, respectively, and the adjusted odds ratios for FIB-4-defined advanced liver fibrosis were 1.03 (0.78 to 1.36), 1.14 (0.82 to 1.57), and 1.97 (1.48 to 2.62) in OW-MAFLD, lean-MAFLD, and DM-MAFLD.

Conclusions

Fibrotic burden in the liver differs across MAFLD subtypes. Optimized surveillance strategies and therapeutic options might be needed for different MAFLD subtypes.

Mass spectrometry-based untargeted metabolomics study of non-obese individuals with non-alcoholic fatty liver disease

OBJECTIVES

Non-alcoholic fatty liver disease (NAFLD) is a disease characterized by the accumulation of excessive fat in the liver, which can lead to fibrosis and has an increasing prevalence. NAFLD requires non-invasive diagnostic biomarkers. While typically observed in overweight individuals, it can also occur in non-obese/non-overweight individuals. Comparative studies on non-obese NAFLD patients are scarce. This study aimed to conduct a using liquid chromatography-high resolution mass spectrometry (LC-MS/MS)-based metabolic profiling of non-obese NAFLD patients and healthy controls.

MATERIALS AND METHODS

The patient group consisted of 27 individuals with NAFLD, while the healthy control group included 39 individuals. Both groups were between 18 and 40 years old, had a BMI of less than 25 and had alcohol consumption less than 20 g/week for men and 10 g/week for women. Serum samples were collected and analyzed using LC-MS/MS. The data were analyzed using the TidyMass and MetaboAnalyst.

RESULTS

The LC-MS/MS analyses detected significant changes in D-amino acid metabolism, vitamin B6 metabolism, apoptosis, mTOR signaling pathway, lysine degradation, and phenylalanine metabolism pathways in non-obese NAFLD patients. Significant changes were also observed in the metabolites D-pantothenic acid, hypoxanthine, citric acid, citramalic acid, L-phenylalanine, glutamine, and histamine-trifluoromethyl-toluidide, β-hydroxymyristic acid, DL-Lactic acid, and 3-methyl-2-oxopentanoic. Overall, the study provides valuable insights into the metabolic changes associated with non-obese NAFLD patients and can contribute to the development of non-invasive diagnostic biomarkers for NAFLD.

CONCLUSIONS

This study sheds light on the metabolic changes in non-obese NAFLD patients. Further research is needed to better understand the metabolic changes associated with NAFLD and to develop effective treatment options.

Nonalcoholic Fatty Liver Disease in Lean/Nonobese and Obese Individuals: A Comprehensive Review on Prevalence, Pathogenesis, Clinical Outcomes, and Treatment

Nonalcoholic fatty liver disease (NAFLD) is the most common liver disease worldwide, with an estimated prevalence of 25% globally. NAFLD is closely associated with metabolic syndrome, which are both becoming increasingly more common with increasing rates of insulin resistance, dyslipidemia, and hypertension. Although NAFLD is strongly associated with obesity, lean or nonobese NAFLD is a relatively new phenotype and occurs in patients without increased waist circumference and with or without visceral fat. Currently, there is limited literature comparing and illustrating the differences between lean/nonobese and obese NAFLD patients with regard to risk factors, pathophysiology, and clinical outcomes. In this review, we aim to define and further delineate different phenotypes of NAFLD and present a comprehensive review on the prevalence, incidence, risk factors, genetic predisposition, and pathophysiology. Furthermore, we discuss and compare the clinical outcomes, such as insulin resistance, dyslipidemia, hypertension, coronary artery disease, mortality, and progression to nonalcoholic steatohepatitis, among lean/nonobese and obese NAFLD patients. Finally, we summarize the most up to date current management of NAFLD, including lifestyle interventions, pharmacologic therapies, and surgical options.

Cardiovascular Morbidity and Mortality Related to Non-alcoholic Fatty Liver Disease: A Systematic Review and Meta-analysis

Whether non-alcoholic fatty liver disease (NAFLD) is a cardiovascular (CV) risk factor is debated. We performed a systematic review and meta-analysis to assess the CV morbidity and mortality related to NAFLD in the general population, and to determine whether CV risk is comparable between lean and non-lean NAFLD phenotypes. We searched multiple databases, including PubMed, Embase, and the Cochrane Library, for observational studies published through 2022 that reported the risk of CV events and mortality. Pooled odds ratios (ORs) and 95% confidence intervals (CIs) for all-cause mortality, CV mortality, myocardial infarction (MI), stroke, atrial fibrillation (AF), and major adverse cardiovascular and cerebrovascular events (MACCE) were assessed through random-effect meta-analysis. We identified 33 studies and a total study population of 10,592,851 individuals (mean age 53±8; male sex 50%; NAFLD 2, 9%). Mean follow-up was 10±6 years. Pooled ORs for all-cause and CV mortality were respectively 1.14 (95% CI, 0.78-1.67) and 1.13 (95% CI, 0.57-2.23), indicating no significant association between NAFLD and mortality. NAFLD was associated with increased risk of MI (OR 1.6; 95% CI, 1.5-1.7), stroke (OR: 1.6; 95% CI, 1.2-2.1), atrial fibrillation (OR: 1.7; 95% CI, 1.2-2.3), and MACCE (OR: 2.3; 95% CI, 1.3-4.2). Compared with non-lean NAFLD, lean NAFLD was associated with increased CV mortality (OR: 1.50; 95% CI, 1.1-2.0), but similar all-cause mortality and risk of MACCE. While NAFLD may not be a risk factor for total and CV mortality, it is associated with excess risk of non-fatal CV events. Lean and non-lean NAFLD phenotypes exhibit distinct prognostic profiles and should receive equitable clinical care.

Epidemiology and prevalence of lean nonalcoholic fatty liver disease and associated cirrhosis, hepatocellular carcinoma, and cardiovascular outcomes in the United States: a population-based study and review of literature

BACKGROUNDS

Nonalcoholic fatty liver disease (NAFLD) is linked to obesity and metabolic syndrome conditions. However, a subset of NAFLD patients express a normal or low body mass index (lean NAFLD [L-NAFLD]). Our aim is to compare the prevalence of L-NAFLD to the obesity-associated NAFLD in the United States by assessing prevalence, potential risk factors, liver-related complications, and coronary artery disease outcomes.

METHODOLOGY

A multicenter database (Explorys Inc.) of >70 million patients across the United States was screened. A cohort of patients with "nonalcoholic fatty liver" between 1999 and 2021 was identified. Two sub-cohorts of NAFLD patients were identified: those with a body mass index (BMI) < 25 kg/m² (L-NAFLD) and those with a BMI > 30 kg/m² (obesity-associated NAFLD). We excluded patients with age <18 and those who have viral hepatitis, hemochromatosis, Wilson's disease, biliary cirrhosis, alcoholic liver disease, cystic fibrosis, alpha-1-antitrypsin deficiency, and autoimmune hepatitis. Multivariate analysis was performed to adjust for confounders.

RESULTS

68 892 260 individuals were screened. NAFLD prevalence was four per 100 000, and L-NAFLD prevalence was 0.6 per 100 000. Compared with those without, patients with L-NAFLD tended to be older (OR 2.16), females (OR 1.28), and smokers (OR 4.67) and of Asian race (OR 2.12). L-NAFLD patients were more likely to have acute coronary syndromes (OR 30.00) and metabolic syndrome (OR 2.31) despite the normal/low BMI. Esophageal varices and hepatocellular carcinoma risks were high in both cirrhosis patients.

CONCLUSION

This is the largest study to assess L-NAFLD prevalence in the United States. L-NAFLD are at a significantly higher risk for acute coronary syndromes, esophageal varices, and hepatocellular carcinoma.

Development of the Rabbit NASH Model Resembling Human NASH and Atherosclerosis

Non-alcoholic steatohepatitis (NASH) is a chronic liver disease which may progress into liver fibrosis and cancer. Since NASH patients have a high prevalence of atherosclerosis and ensuing cardiovascular diseases, simultaneous management of NASH and atherosclerosis is required. Currently, rodents are the most common animal models for NASH and accompanying liver fibrosis, but there are great differences in lipoprotein profiles between rodents and humans, which makes it difficult to reproduce the pathology of NASH patients with atherosclerosis. Rabbits can be a promising candidate for assessing NASH and atherosclerosis because lipoprotein metabolism is more similar to humans compared with rodents. To develop the NASH model using rabbits, we treated the Japanese White rabbit with a newly developed high-fat high-cholesterol diet (HFHCD) containing palm oil 7.5%, cholesterol 0.5%, and ferrous citrate 0.5% for 16 weeks. HFHCD-fed rabbits exhibited NASH at 8 weeks after commencing the treatment and developed advanced fibrosis by the 14th week of treatment. In addition to hypercholesterolemia, atherosclerotic lesion developed in the aorta after 8 weeks. Therefore, this rabbit NASH model might contribute to exploring the concurrent treatment options for human NASH and atherosclerosis.

Association Between Hypertension and New-Onset Non-Alcoholic Fatty Liver Disease in Chinese Non-Obese People: A Longitudinal Cohort Study

BACKGROUND

Quantification of the relationship between hypertension and non-alcoholic fatty liver disease (NAFLD) risk is limited and controversial. This study aimed to investigate the relationship between hypertension and NAFLD in non-obese Chinese and to use different methods to demonstrate that hypertension is an independent risk factor for NAFLD.

METHODS

On 16,153 nonobese individuals, a retrospective cohort study was conducted in China to examine the impact of hypertension on incident NAFLD. We compared five methods: multivariable Cox proportional-hazards regression, propensity score-matched (PSM) analysis, propensity score adjustment method (considering the propensity score as a covariate in a multivariable Cox proportional-hazard regression), and two propensity score-based weighted methods-The first one estimated the hypertension effect in the overall study population-inverse probability of treatment weights (IPTW), the other in the hypertensive population-standardized mortality ratio (SMR) weights. We also used a genetic matching (GenMatch) algorithm to match the participants for sensitive analysis.

RESULTS

Between 2010 and 2014, 16,153 participants met our inclusion criteria, including 2427 (15.03%) with hypertension. A total of 2321 (14.37%) participants developed NAFLD during the median follow-up of 2.98 years. The crude hazard ratio (HR) between hypertension and incident NAFLD was 2.05 (95% confidence interval (CI): 1.87, 2.25). The adjusted HR depended on the different methods, ranging from 1.09 (95% CI: 0.77, 1.23) for the PSM method to 2.24 (95% CI: 2.05, 2.44) for the SMR weighted analysis. Hypertensive participants with high propensity scores had a higher risk of developing NAFLD in the future. Excluding participants with propensity scores <8% yielded comparable hazard ratios with a narrower range, from 1.04 to 1.80. After adjusting for the confounding variables, the relationship also existed in the GenMatch cohort as a sensitivity analysis (HR=1.06, 95% CI 1.01-1.13).

CONCLUSION

Hypertension is a significant cause of NAFLD in Chinese adults in non-obese Chinese adults, with the hazard ratio ranging from 1.09 to 2.24.

Pemafibrate therapy for non-alcoholic fatty liver disease is more effective in lean patients than obese patients

Introduction

Non-alcoholic fatty liver disease (NAFLD) is the most common chronic liver disease in the world, with an increasing incidence. Pemafibrate is a novel selective peroxisome proliferator-activated receptor-a (PPAR-a) modulator which is expected to improve NAFLD. The aim of this study is to identify predictors of improvement of hepatic inflammation and fibrosis after pemafibrate therapy in patients with NAFLD.

Material and methods

Seventy-one non-diabetic patients with NAFLD treated with pemafibrate for more than six months were included in this retrospective review. Hepatic inflammation and fibrosis were evaluated by alanine aminotransferase (ALT) and Mac-2 binding protein glycosylation isomer (M2BPGi) levels, respectively.

Results

During six months of pemafibrate therapy, significant improvements were observed in ALT and M2BPGi levels regardless of the body mass index (BMI) compared to baseline. Lean NAFLD was identified as a significant positive predictor for > 50% reduction of ALT showing reduced hepatic inflammation. Subsequent multivariate analysis confirmed this result. Reduction of ALT in the lean NAFLD group (BMI < 25) was significantly greater than in the obese NAFLD group (BMI > 30) (p = 0.034). Lean NAFLD and age > 50 years were identified as significant positive predictors for > 20% reduction of M2BPGi showing reduced hepatic fibrosis. Subsequent multivariate analysis confirmed these results. Reduction of M2BPGi in the lean NAFLD group was significantly greater than in the obese NAFLD group (p = 0.022).

Conclusions

Pemafibrate therapy improves markers of hepatic inflammation and fibrosis regardless of BMI. Patients with lean NAFLD have a greater response to pemafibrate therapy compared to those with obese NAFLD.

Gamma-glutamyl transferase to high-density lipoprotein cholesterol ratio has a non-linear association with non-alcoholic fatty liver disease: A secondary prospective cohort study in non-obese Chinese adults

OBJECTIVE

The evidence for a relationship between the ratio of gamma-glutamyl transferase (GGT) to high-density lipoprotein cholesterol (HDL-c) and non-alcoholic fatty liver disease (NAFLD) is currently inadequate. This study aimed to investigate the relationship between the GGT/HDL-c ratio and NAFLD.

MATERIALS AND METHODS

This study is a prospective cohort study that recruited a total of 11,891 non-obese volunteers in a Chinese hospital from January 2010 to December 2014 in a non-selective manner. The Cox proportional-hazards regression model was then used to investigate the relationship between baseline GGT/HDL-c ratio and the probability of developing NAFLD. The non-linear link between the GGT/HDL-c ratio and NAFLD was identified using a Cox proportional hazards regression with cubic spline functions and smooth curve fitting (cubic spline smoothing). Furthermore, we conducted several sensitivity and subgroup analyses. Data had been uploaded to the DATADRYAD website.

RESULTS

The mean age of study participants was 43.29 ± 14.95 years old, and 6,502 (54.68%) were male. The median (interquartile ranges) of GGT/HDL-c ratio was 15.56 (10.73-23.84). During a median follow-up of 29.35 months, 2028 (17.05%) participants were diagnosed with NAFLD. After adjusting for covariates, the results showed that GGT/HDL-c ratio was positively associated with incident NAFLD (HR = 1.014, 95% CI 1.011-1.017). There was also a non-linear relationship between GGT/HDL-c ratio and NAFLD, and the inflection point of the GGT/HDL-c ratio was 20.35. The effect sizes (HR) on the left and right sides of the inflection point were 1.113 (95% CI 1.096, 1.130) and 1.003 (95% CI 1.000-1.007), respectively. Moreover, the sensitivity analysis demonstrated the robustness of our results. Subgroup analysis showed that GGT/HDL-c ratio was more strongly associated with incident NAFLD in triglyceride (TG) < 1.7 mmol/L participants. In contrast, the weaker association was probed in those with TG ≥ 1.7 mmol/L.

CONCLUSION

The present study reveals a positive and non-linear relationship between the GGT/HDL-c ratio and NAFLD risk in a non-obese Chinese population. GGT/HDL-c ratio is strongly associated with NAFLD when GGT/HDL-c ratio is less than 20.35. Therefore, maintaining the GGT/HDL-c ratio lower than the inflection point is recommended from a treatment perspective.

Outcomes of subjects who are lean, overweight or obese with nonalcoholic fatty liver disease: A cohort study in China

The ability to determine the prognosis of lean nonalcoholic fatty liver disease (NAFLD) is essential for decision making in clinical settings. Using a large community-based Chinese cohort, we aimed to investigate NAFLD outcomes by body mass index (BMI). We used the restricted cubic splines method to investigate the dose-response relationship between BMI and outcomes in subjects with NAFLD and those without NAFLD. We included 73,907 subjects from the Kailuan cohort and grouped all subjects into four phenotypes by using NAFLD and BMI (<23 kg/m² ). The probability of developing outcomes for individuals with lean NAFLD (LN), overweight/obese NAFLD (ON), overweight/obese non-NAFLD (ONN), and lean non-NAFLD (LNN) was estimated. We found a U-shaped association between BMI and death but a linear positive association concerning cardiovascular disease (CVD) after adjusting for age and other covariates. Compared with the LNN group, the adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) of the LN, ON, and ONN groups were 1.30 (1.14-1.49), 0.86 (0.80-0.91), 0.84 (0.80-0.89) for all-cause death, 2.61 (1.13-6.03), 0.74 (0.44-1.26), 1.10 (0.70-1.74) for liver-related death, 2.12 (1.46-3.08), 1.23 (0.99-1.54), 1.19 (0.98-1.43) for digestive system cancers, and 2.04 (1.40-2.96), 1.30 (1.05-1.61), 1.21 (1.01-1.46) for obesity-related cancers. Subjects with LN had a significantly higher risk of colorectal cancer and esophagus cancer. However, the ON group had the highest CVD risk (HR, 1.39; 95% CI, 1.27-1.52). The LN group with hypertension had a higher risk of adverse outcomes, and those without hypertension had a similar risk compared to LNN. Conclusion: Subjects with LN may experience a higher risk of all-cause death, digestive system cancers, and obesity-related cancers than the other three groups but a lower risk of CVD than ON subjects. LN with hypertension may be a high-risk phenotype.

The new exploration of pure total flavonoids extracted from Citrus maxima (Burm.) Merr. as a new therapeutic agent to bring health benefits for people

The peel and fruit of Citrus varieties have been a raw material for some traditional Chinese medicine (TCM). Pure total flavonoids from Citrus maxima (Burm.) Merr. (PTFC), including naringin, hesperidin, narirutin, and neohesperidin, have been attracted increasing attention for their multiple clinical efficacies. Based on existing in vitro and in vivo research, this study systematically reviewed the biological functions of PTFC and its components in preventing or treating liver metabolic diseases, cardiovascular diseases, intestinal barrier dysfunction, as well as malignancies. PTFC and its components are capable of regulating glycolipid metabolism, blocking peroxidation and persistent inflammation, inhibiting tumor progression, protecting the integrity of intestinal barrier and positively regulating intestinal microbiota, while the differences in fruit cultivation system, picking standard, manufacturing methods, delivery system and individual intestinal microecology will have impact on the specific therapeutic effect. Thus, PTFC is a promising drug for the treatment of some chronic diseases, as well as continuous elaborate investigations are necessary to improve its effectiveness and bioavailability.

Triglyceride affects the association between estimated glomerular filtration rate and the onset of non-alcoholic fatty liver disease: A second analysis of a Chinese cohort study

Objective

The role of triglyceride (TG) and estimated glomerular filtration rate (eGFR) effect modifiers on the risk of non-alcoholic fatty liver disease (NAFLD) is unknown. This study examined whether TG modifies the relationship between eGFR and incident NAFLD.

Methods

In a Chinese hospital from January 2010 to December 2014, 15,555 non-obese subjects were collected systematically for this retrospective cohort study. The target-independent and dependent variables were eGFR measured at baseline and NAFLD appearing during follow-up. The modified variable was TG measured at baseline. The multivariate Cox proportional hazards model was used to explore eGFR and TG’s association with NAFLD risk. We explored a priori interaction between eGFR and TG, and performed subgroup analyses to further assess whether the relationship between eGFR and incident NAFLD was modified by TG. We also explored the effect of TG and eGFR interaction on the risk of NAFLD.

Results

The mean age was 43.09 ± 14.92 years, and 8,131 (52.27%) were males. During a median follow-up time of 35.8 months, 2,077 (13.35%) individuals developed NAFLD. In the adjusted model, eGFR was negatively associated with incident NAFLD (HR = 0.984, 95% CI: 0.982, 0.987), while TG was positively related to NAFLD (HR = 1.582, 95% CI: 1.490, 1.681). TG could modify the relationship between eGFR and incident NAFLD. A stronger association between eGFR and NAFLD could be found in the participants without hypertriglyceridemia (HTG) (HR = 0.981, 95% CI: 0.978–0.984, P for interaction = 0.0139). In contrast, the weaker association was probed in the population with HTG (HR = 0.986, 95% CI: 0.983–0.989). At the same time, we also found an interaction between eGFR and TG in influencing NAFLD risk. In participants with decreased eGFR and HTG, the risk of NAFLD was significantly increased. Further, compared to non-HTG subjects with eGFR ≥ 116.56 ml/min/1.73 m², participants with HTG and eGFR < 82.88 ml/min/1.73 m² had about a fourfold increase in the risk (HR = 4.852 95% CI: 3.943–5.970) of NAFLD.

Conclusion

eGFR and TG is independently associated with NAFLD risk. The association of eGFR with incident NAFLD is likely to be modified by TG in the Chinese non-obese population. There was an interactive effect between eGFR and TG in affecting NAFLD risk. In participants with decreased eGFR and hypertriglyceridemia, the risk of NAFLD is significantly increased.

Association between serum uric acid-to-creatinine ratio and non-alcoholic fatty liver disease: a cross-sectional study in Chinese non-obese people with a normal range of low-density lipoprotein cholesterol

Objective

Evidence regarding the relationship between serum uric acid-to-creatinine (SUA/Scr) ratio and non-alcoholic fatty liver disease (NAFLD) in Chinese non-obese people is still limited. Therefore, the present study was undertaken to analyze the association between the SUA/Scr ratio and NAFLD.

Methods

This study was a cross-sectional study that non-selectively and consecutively collected 182,320 non-obese individuals with a normal range of low-density lipoprotein cholesterol in a Chinese hospital from January 2010 to December 2014. A binary logistic regression model was used to evaluate the independent association between the SUA/Scr ratio and NAFLD. A generalized additive model (GAM) and smooth curve fitting (penalized spline method) was conducted to explore the exact shape of the curve between them. A series of sensitivity analyses were used to ensure the robustness of the results. Moreover, subgroup analyses were conducted. In addition, the diagnostic value of the SUA/Scr ratio for NAFLD was evaluated based on the area under the receiver-operating characteristic curve (AUROC). It was stated that the data had been uploaded to the DATADRYAD website.

Results

The average participants' age was 40.96 ± 14.05 years old, and 90,305 (49.5%) were male. The prevalence of NAFLD was 13.7%, and the mean SUA/Scr was 3.62 ± 0.92. After adjusting covariates, the results showed that SUA/Scr ratio was positively associated with NAFLD (OR = 1.424, 95%CI: 1.396, 1.454). There was also a non-linear relationship between SUA/Scr ratio and NAFLD in participants with normal kidney function, and the inflection point of the SUA/Scr ratio was 4.425. The effect sizes (OR) on the left and right sides of the inflection point were 1.551 (1.504, 1.599) and 1.234 (1.179, 1.291), respectively. And the sensitive analysis demonstrated the robustness of the results. Subgroup analysis showed a stronger association between SUA/Scr ratio and NAFLD in females and the population with age < 50 years, FPG ≤ 6.1 mmol/L, BMI < 24 kg/m², and HDL-c ≥ 1 mmol/L. In contrast, the weaker association was probed in males and the population with age ≥ 50 years, BMI ≥ 24 kg/m², FPG > 6.1 mmol/L, and HDL-c < 1 mmol/L. The SUA/Scr ratio had an AUC of 0.6624 (95% CI 0.6589, 0.6660) for diagnosing NAFLD. Based on the best cut-off value of 3.776, the negative predictive value of the SUA/Scr ratio for identifying NAFLD was 91.0%.

Conclusion

This study demonstrates an independent positive association between SUA/Scr ratio and NAFLD in Chinese non-obese people with a normal range of low-density lipoprotein cholesterol. There is also a non-linear relationship between the SUA/Scr ratio and NAFLD in participants with normal kidney function, and the SUA/Scr ratio is strongly related to NAFLD when SUA/Scr ratio is less than 4.425. The SUA/Scr ratio has a certain reference value for determining NAFLD. When the SUA/Scr ratio is lower than 3.776, identifying NAFLD patients with low risk is a great reference.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12876-022-02500-w.

Long-term cardiovascular outcomes differ across metabolic dysfunction-associated fatty liver disease subtypes among middle-aged population

BACKGROUND AND AIMS

The new metabolic dysfunction-associated fatty liver disease (MAFLD) criteria include the following three distinct subtypes: MAFLD with diabetes mellitus (DM), overweight/obese (OW), or lean/normal weight with metabolic dysfunction. We investigated whether long-term cardiovascular disease outcomes differ across the MAFLD subtypes.

METHODS

From a nationwide health screening database, we included 8,412,730 participants (48.6% males) aged 40-64 years, free of cardiovascular disease history, between 2009 and 2010. Participants were categorized into non-MAFLD, OW-MAFLD, lean-MAFLD, and DM-MAFLD. The primary outcome was a composite cardiovascular disease event, including myocardial infarction, ischemic stroke, heart failure, or cardiovascular disease-related death. The presence of advanced liver fibrosis was estimated using a BARD score ≥ 2.

RESULTS

Among the study participants, 3,087,640 (36.7%) had MAFLD, among which 2,424,086 (78.5%), 170,761 (5.5%), and 492,793 (16.0%) had OW-MAFLD, lean-MAFLD, and DM-MAFLD, respectively. Over a median follow-up period of 10.0 years, 169,433 new cardiovascular disease events occurred. With the non-MAFLD group as reference, multivariable-adjusted hazard ratios (95% confidence intervals) for cardiovascular disease events were 1.16 (1.15-1.18), 1.23 (1.20-1.27), and 1.82 (1.80-1.85) in the OW-MAFLD, lean-MAFLD, and DM-MAFLD groups, respectively. Participants with lean-MAFLD or DM-MAFLD had a higher cardiovascular disease risk than those with OW-MAFLD, irrespective of metabolic abnormalities or comorbidities. The presence of advanced liver fibrosis was significantly associated with a higher cardiovascular disease risk in each MAFLD subtype.

CONCLUSION

Long-term cardiovascular disease outcomes differed across the MAFLD subtypes. Further studies are required to investigate whether preventive or therapeutic interventions should be optimized according to the MAFLD subtypes.

Association between non-alcoholic fatty liver disease and metabolically healthy deterioration across different body shape phenotypes at baseline and change patterns

Non-alcoholic fatty liver disease (NAFLD) is a hepatic manifestation of metabolic syndrome (MetS), and the relationship between NAFLD and metabolic deterioration remains unclear. This study aimed to investigate dynamic changes in metabolically healthy phenotypes and to assess the impact of non-alcoholic fatty liver disease (NAFLD) on the conversion from metabolically healthy (MH) to metabolically unhealthy (MU) phenotypes across body shape phenotypes and phenotypic change patterns. We defined body shape phenotypes using both the body mass index (BMI) and waist circumference (WC) and defined metabolic health as individuals scoring ≤ 1 on the NCEP-ATP III criteria, excluding WC. A total of 12,910 Chinese participants who were MH at baseline were enrolled in 2013 and followed-up in 2019 or 2020. During a median follow-up of 6.9 years, 27.0% (n = 3,486) of the MH individuals developed an MU phenotype. According to the multivariate Cox analyses, NAFLD was a significant predictor of conversion from the MH to MU phenotype, independent of potential confounders (HR: 1.12; 95% confidence interval: 1.02–1.22). For the MH-normal weight group, the relative risk of NAFLD in phenotypic conversion was 1.21 (95% CI 1.03–1.41, P = 0.017), which was relatively higher than that of MH-overweight/obesity group (HR: 1.14, 95% CI 1.02–1.26, P = 0.013). Interestingly, the effect of NAFLD at baseline on MH deterioration was stronger in the “lean” phenotype group than in the “non-lean” phenotype group at baseline and in the “fluctuating non-lean” phenotype change pattern group than in the “stable non-lean” phenotype change pattern group during follow-up. In conclusion, lean NAFLD is not as benign as currently considered and requires more attention during metabolic status screening.

New Insights into Non-Alcoholic Fatty Liver Disease and Coronary Artery Disease: The Liver-Heart Axis

Non-alcoholic fatty liver disease (NAFLD) represents the hepatic expression of the metabolic syndrome and is the most prevalent liver disease. NAFLD is associated with liver-related and extrahepatic morbi-mortality. Among extrahepatic complications, cardiovascular disease (CVD) is the primary cause of mortality in patients with NAFLD. The most frequent clinical expression of CVD is the coronary artery disease (CAD). Epidemiological data support a link between CAD and NAFLD, underlain by pathogenic factors, such as the exacerbation of insulin resistance, genetic phenotype, oxidative stress, atherogenic dyslipidemia, pro-inflammatory mediators, and gut microbiota. A thorough assessment of cardiovascular risk and identification of all forms of CVD, especially CAD, are needed in all patients with NAFLD regardless of their metabolic status. Therefore, this narrative review aims to examine the available data on CAD seen in patients with NAFLD, to outline the main directions undertaken by the CVD risk assessment and the multiple putative underlying mechanisms implicated in the relationship between CAD and NAFLD, and to raise awareness about this underestimated association between two major, frequent and severe diseases.

The role of microbiota in nonalcoholic fatty liver disease

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

Evaluated Glomerular Filtration Rate Is Associated With Non-alcoholic Fatty Liver Disease: A 5-Year Longitudinal Cohort Study in Chinese Non-obese People

Objective

Evidence regarding the association between evaluated glomerular filtration rate (eGFR) and non-alcoholic fatty liver disease (NAFLD) is still limited. On that account, the purpose of our research is to survey the link of evaluated eGFR on NAFLD.

Methods

This study is a retrospective cohort study. Which consecutively and non-selectively collected a total of 16,138 non-obese participants in a Chinese hospital from January 2010 to December 2014. We then used the Cox proportional-hazards regression model to explore the relationship between baseline eGFR and NAFLD risk. A Cox proportional hazards regression with cubic spline functions and smooth curve fitting (the cubic spline smoothing) was used to identify the non-linear relationship between eGFR and NAFLD. Additionally, we also performed a series of sensitivity analyses and subgroup analyses. Data had been uploaded to the DATADRYAD website.

Results

The mean age of the included individuals was 43.21 ± 14.95 years old, and 8,467 (52.47%) were male. The mean baseline eGFR was 98.83 ± 22.80 mL/min per 1.73m2. During a median follow-up time of 35.8 months, 2,317 (14.36%) people experienced NAFLD. After adjusting covariates, the results showed that eGFR was negatively associated with incident NAFLD (HR = 0.983, 95%CI: 0.980, 0.985). There was also a non-linear relationship between eGFR and NAFLD, and the inflection point of eGFR was 103.489 mL/min per 1.73 m2. The effect sizes (HR) on the left and right sides of the inflection point were 0.988 (0.984, 0.991) and 0.971 (0.963, 0.979), respectively. And the sensitive analysis demonstrated the robustness of our results. Subgroup analysis showed that eGFR was more strongly associated with incident NAFLD in diastolic blood pressure (DBP) &lt; 90 mmHg, fasting plasma glucose (FPG) ≤ 6.1 mmol/L, high-density lipoprotein cholesterol (HDL-c) &lt; 1 mmol/L, and alanine aminotransferase (ALT) ≥ 40 U/L participants. In contrast, the weaker association was probed in those with DBP ≥ 90 mmHg, ALT &lt; 40 U/L, FPG &gt; 6.1 mmol/L, and HDL-c ≥ 1 mmol/L.

Conclusion

This study demonstrates a negative and non-linear association between eGFR and incident NAFLD in the Chinese non-obese population. eGFR is strongly related to NAFLD when eGFR is above 103 mL/min per 1.73 m2. From a therapeutic perspective, it makes sense to maintain eGFR levels within the inflection point to 130 mL/min/1.73 m2.

Inhibition of ATP-citrate lyase improves NASH, liver fibrosis, and dyslipidemia

Elevated liver de novo lipogenesis contributes to non-alcoholic steatohepatitis (NASH) and can be inhibited by targeting acetyl-CoA carboxylase (ACC). However, hypertriglyceridemia limits the use of pharmacological ACC inhibitors as a monotherapy. ATP-citrate lyase (ACLY) generates acetyl-CoA and oxaloacetate from citrate, but whether inhibition is effective for treating NASH is unknown. Here, we characterize a new mouse model that replicates many of the pathological and molecular drivers of NASH and find that genetically inhibiting ACLY in hepatocytes reduces liver malonyl-CoA, oxaloacetate, steatosis, and ballooning as well as blood glucose, triglycerides, and cholesterol. Pharmacological inhibition of ACLY mirrors genetic inhibition but has additional positive effects on hepatic stellate cells, liver inflammation, and fibrosis. Mendelian randomization of human variants that mimic reductions in ACLY also associate with lower circulating triglycerides and biomarkers of NASH. These data indicate that inhibiting liver ACLY may be an effective approach for treatment of NASH and dyslipidemia.

Nonalcoholic Fatty Liver Disease and Cardiovascular Risk: A Scientific Statement From the American Heart Association

Nonalcoholic fatty liver disease (NAFLD) is an increasingly common condition that is believed to affect >25% of adults worldwide. Unless specific testing is done to identify NAFLD, the condition is typically silent until advanced and potentially irreversible liver impairment occurs. For this reason, the majority of patients with NAFLD are unaware of having this serious condition. Hepatic complications from NAFLD include nonalcoholic steatohepatitis, hepatic cirrhosis, and hepatocellular carcinoma. In addition to these serious complications, NAFLD is a risk factor for atherosclerotic cardiovascular disease, which is the principal cause of death in patients with NAFLD. Accordingly, the purpose of this scientific statement is to review the underlying risk factors and pathophysiology of NAFLD, the associations with atherosclerotic cardiovascular disease, diagnostic and screening strategies, and potential interventions.

NAFLD in normal weight individuals

Nonalcoholic fatty liver disease (NAFLD) can develop in lean individuals. Despite a better metabolic profile, the risk of disease progression to hepatic inflammation, fibrosis, and decompensated cirrhosis in the lean is similar to that in obesity-related NAFLD and lean individuals may experience more severe hepatic consequences and higher mortality relative to those with a higher body mass index (BMI). In the absence of early symptoms and abnormal laboratory findings, lean individuals are not likely to be screened for NAFLD or related comorbidities; however, given the progressive nature of the disease and the increased risk of morbidity and mortality, a clearer understanding of the natural history of NAFLD in lean individuals, as well as efforts to raise awareness of the potential health risks of NAFLD in lean individuals, are warranted. In this review, we summarize available data on NAFLD prevalence, clinical characteristics, outcomes, and mortality in lean individuals and discuss factors that may contribute to the development of NAFLD in this population, including links between dietary and genetic factors, menopausal status, and ethnicity. We also highlight the need for greater representation of lean individuals in NAFLD-related clinical trials, as well as more studies to better characterize lean NAFLD, develop improved screening algorithms, and determine specific treatment strategies based on underlying etiology.

The advantages of physical exercise as a preventive strategy against NAFLD in postmenopausal women

BACKGROUND

The prevalence and severity of nonalcoholic fatty liver disease (NAFLD) increase in women after menopause. This narrative review discusses the causes and consequences of NAFLD in postmenopausal women and describes how physical activity can contribute to its prevention.

METHODS

The authors followed the narrative review method to perform a critical and objective analysis of the current knowledge on the topic. The Medical Subject Heading keywords 'physical exercise', 'menopause', 'hormone replacement therapy', 'estradiol' and 'NAFLD' were used to establish a conceptual framework. The databases used to collect relevant references included Medline and specialized high-impact journals.

RESULTS

Higher visceral adiposity, higher rate of lipolysis in adipose tissue after oestrogen drop and changes in the expression of housekeeping proteins involved in hepatic lipid management are observed in women after menopause, contributing to NAFLD. Excessive liver steatosis leads to hepatic insulin resistance, oxidative stress and inflammation, accelerating NAFLD progression. Physical activity brings beneficial effects against several postmenopausal-associated complications, including NAFLD progression. Aerobic and resistance exercises partially counteract alterations induced by metabolic syndrome in sedentary postmenopausal women, impacting NAFLD progression and severity.

CONCLUSIONS

With the increased global obesity epidemic in developing countries, NAFLD is becoming a severe problem with increased prevalence in women after menopause. Evidence shows that physical activity may delay NAFLD development and severity in postmenopausal women, although the prescription of age-appropriate physical activity programmes is advisable to assure the health benefits.

Synergistic and Detrimental Effects of Alcohol Intake on Progression of Liver Steatosis

Nonalcoholic fatty liver disease (NAFLD) and alcoholic liver disease (ALD) are the most common liver disorders worldwide and the major causes of non-viral liver cirrhosis in the general population. In NAFLD, metabolic abnormalities, obesity, and metabolic syndrome are the driving factors for liver damage with no or minimal alcohol consumption. ALD refers to liver damage caused by excess alcohol intake in individuals drinking more than 5 to 10 daily units for years. Although NAFLD and ALD are nosologically considered two distinct entities, they show a continuum and exert synergistic effects on the progression toward liver cirrhosis. The current view is that low alcohol use might also increase the risk of advanced clinical liver disease in NAFLD, whereas metabolic factors increase the risk of cirrhosis among alcohol risk drinkers. Therefore, special interest is now addressed to individuals with metabolic abnormalities who consume small amounts of alcohol or who binge drink, for the role of light-to-moderate alcohol use in fibrosis progression and clinical severity of the liver disease. Evidence shows that in the presence of NAFLD, there is no liver-safe limit of alcohol intake. We discuss the epidemiological and clinical features of NAFLD/ALD, aspects of alcohol metabolism, and mechanisms of damage concerning steatosis, fibrosis, cumulative effects, and deleterious consequences which include hepatocellular carcinoma.

Metabolic associated fatty liver disease is a risk factor for chronic kidney disease

BACKGROUND AND AIMS

To clarify the relationship between metabolic dysfunction-associated fatty liver disease (MAFLD) and chronic kidney disease (CKD).

METHODS

The participants were divided into four groups by the presence or absence of fatty liver disease (FLD) and metabolic dysfunction (MD). MAFLD was defined as having both FLD and MD, whereas CKD was defined as having an estimated glomerular filtration rate of <60 mL/min/1.73 m2 and/or proteinuria.

RESULTS

In this cross-sectional study of 27,371 participants, the proportions of those in the non-FLD without MD, non-FLD with MD, FLD without MD, and MAFLD groups were 48.7, 28.2, 2.3, and 20.8%, respectively. Compared with non-FLD without MD, MAFLD was associated with the risk of CKD (adjusted odds ratio 1.83 [1.66-2.01], P < 0.001), whereas FLD without MD was not (1.02 [0.79-1.33], P = 0.868). Moreover, compared with FLD without MD, MAFLD was associated with the risk of CKD (1.19 [1.09-1.31], P < 0.001). In this retrospective cohort study, 16,938 of 27,371 participants underwent a median 4.6 (2.0-8.1) years follow-up, and incident data of non-FLD without MD, non-FLD with MD, FLD without MD, and MAFLD were 21.0, 31.1, 26.1, and 31.1 cases per 1,000 person-years, respectively. Compared with the non-FLD without MD, MAFLD was associated with the risk of incident CKD (adjusted hazard ratio 1.24 [1.14-1.36], P < 0.001), whereas FLD without MD was not (1.11 [0.85-1.41], P = 0.433).

CONCLUSIONS

MAFLD was associated with a risk of CKD, whereas FLD without MD was not a risk for CKD.

Association between the atherogenic index of plasma and new-onset non-alcoholic fatty liver disease in non-obese participants

INTRODUCTION

Non-alcoholic fatty liver disease (NAFLD) in the non-obese population accounts for a large proportion of NAFLD. Atherogenic index of plasma (AIP, defined as the logarithm of the triglyceride/high-density lipoprotein cholesterol ratio.) can provide a stronger reflection of dyslipidemia and studies on the longitudinal association between AIP and NAFLD were limited in non-obese participants, especially in different BMI groups.

METHODS

We performed a post-hoc analysis of data obtained from the Dryad data repository (Dryad is a nonprofit open database of medicine.) and explored the predictive value of AIP on the risk of NAFLD among non-obese participants.

RESULTS

This study included 16173 participants with AIP, of which 2322(14.4%) non-obese participants developed into individuals with NAFLD with the 5-year follow-up examination. The difference between AIP quartiles in the cumulative estimation of new-onset NAFLD was significant, and with increased AIP, the cumulative new-onset NAFLD gradually increased. Participants in higher AIP quartiles had a significantly increased risk of NAFLD. In the fully adjusted model 3, hazard ratios of the new-onset NAFLD for subjects in Q2, Q3, and Q4 of AIP were 2.00 (1.59, 2.53), 2.61 (2.09, 3.72), and 4.49 (3.62, 5.57) respectively. Meanwhile, the trend test for the association between AIP quartiles and the new-onset NAFLD presented that AIP quartile was positively and strongly associated with the new-onset NAFLD (adjusted hazard ratio (95%CI) in Model 3: 1.59 (1.51, 1.67), P<0.001). We found that AIP was also positively and strongly associated with new-onset NAFLD in different sex groups and different age groups in female patients. Moreover, the predictive ability of AIP was no significant difference in different sex groups and different age groups in female patients. In the subgroup analysis, we found that in the low BMI population, the predictive effect of AIP for new-onset NAFLD was expanded by 2-3 times for each quality increase of AIP.

CONCLUSION

This study found that AIP was a strong independent risk factor for new-onset NAFLD among non-obese individuals especially in the low BMI participants, and screening for AIP in this population can be used to prevent future NAFLD.

Intestinal Barrier and Permeability in Health, Obesity and NAFLD

The largest surface of the human body exposed to the external environment is the gut. At this level, the intestinal barrier includes luminal microbes, the mucin layer, gastrointestinal motility and secretion, enterocytes, immune cells, gut vascular barrier, and liver barrier. A healthy intestinal barrier is characterized by the selective permeability of nutrients, metabolites, water, and bacterial products, and processes are governed by cellular, neural, immune, and hormonal factors. Disrupted gut permeability (leaky gut syndrome) can represent a predisposing or aggravating condition in obesity and the metabolically associated liver steatosis (nonalcoholic fatty liver disease, NAFLD). In what follows, we describe the morphological-functional features of the intestinal barrier, the role of major modifiers of the intestinal barrier, and discuss the recent evidence pointing to the key role of intestinal permeability in obesity/NAFLD.

Metabolic-Associated Fatty Liver Disease (MAFLD), Diabetes, and Cardiovascular Disease: Associations with Fructose Metabolism and Gut Microbiota

Non-alcoholic fatty liver disease (NAFLD) is an increasingly common condition associated with type 2 diabetes (T2DM) and cardiovascular disease (CVD). Since systemic metabolic dysfunction underlies NAFLD, the current nomenclature has been revised, and the term metabolic-associated fatty liver disease (MAFLD) has been proposed. The new definition emphasizes the bidirectional relationships and increases awareness in looking for fatty liver disease among patients with T2DM and CVD or its risk factors, as well as looking for these diseases among patients with NAFLD. The most recommended treatment method of NAFLD is lifestyle changes, including dietary fructose limitation, although other treatment methods of NAFLD have recently emerged and are being studied. Given the focus on the liver-gut axis targeting, bacteria may also be a future aim of NAFLD treatment given the microbiome signatures discriminating healthy individuals from those with NAFLD. In this review article, we will provide an overview of the associations of fructose consumption, gut microbiota, diabetes, and CVD in patients with NAFLD.

Electronic health record-based genome-wide meta-analysis provides insights on the genetic architecture of non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is a complex disease linked to several chronic diseases. We aimed at identifying genetic variants associated with NAFLD and evaluating their functional consequences. We performed a genome-wide meta-analysis of 4 cohorts of electronic health record-documented NAFLD in participants of European ancestry (8,434 cases and 770,180 controls). We identify 5 potential susceptibility loci for NAFLD (located at or near GCKR, TR1B1, MAU2/TM6SF2, APOE, and PNPLA3). We also report a potentially causal effect of lower LPL expression in adipose tissue on NAFLD susceptibility and an effect of the FTO genotype on NAFLD. Positive genetic correlations between NAFLD and cardiometabolic diseases and risk factors such as body fat accumulation/distribution, lipoprotein-lipid levels, insulin resistance, and coronary artery disease and negative genetic correlations with parental lifespan, socio-economic status, and acetoacetate levels are observed. This large GWAS meta-analysis reveals insights into the genetic architecture of NAFLD.

Lipid Metabolism Disorders in the Comorbid Course of Nonalcoholic Fatty Liver Disease and Chronic Obstructive Pulmonary Disease

Non-alcoholic fatty liver disease (NAFLD) is currently among the most common liver diseases. Unfavorable data on the epidemiology of metabolic syndrome and obesity have increased the attention of clinicians and researchers to the problem of NAFLD. The research results allow us to emphasize the systemicity and multifactoriality of the pathogenesis of liver parenchyma lesion. At the same time, many aspects of its classification, etiology, and pathogenesis remain controversial. Local and systemic metabolic disorders are also a part of the pathogenesis of chronic obstructive pulmonary disease and can influence its course. The present article analyzes the metabolic pathways mediating the links of impaired lipid metabolism in NAFLD and chronic obstructive pulmonary disease (COPD). Free fatty acids, cholesterol, and ceramides are involved in key metabolic and inflammatory pathways underlying the pathogenesis of both diseases. Moreover, inflammation and lipid metabolism demonstrate close links in the comorbid course of NAFLD and COPD.

Non-alcoholic fatty liver disease and risk of fatal and non-fatal cardiovascular events: an updated systematic review and meta-analysis

BACKGROUND

Studies have reported a significant association between non-alcoholic fatty liver disease (NAFLD) and increased incidence of cardiovascular disease (CVD). However, the magnitude of the risk and whether this risk changes with the severity of NAFLD remains uncertain. We performed a meta-analysis of observational studies to quantify the magnitude of the association between NAFLD and risk of incident CVD events.

METHODS

We systematically searched PubMed, Scopus, and Web of Science from database inception to July 1, 2021, to identify eligible observational studies examining the risk of incident CVD events amongst adult (age ≥18 years) individuals with and without NAFLD and in which NAFLD was diagnosed by imaging, International Classification of Diseases codes, or liver biopsy. The primary outcomes were CVD death, non-fatal CVD events, or both. Data from selected studies were extracted, and meta-analysis was performed using random-effects models to obtain summary hazard ratios (HRs) with 95% CIs. The quality of the evidence was assessed with the Cochrane risk of bias tool. This study is registered on Open Science Framework, number osf.io/5z7gf.

FINDINGS

We identified 36 longitudinal studies with aggregate data on 5 802 226 middle-aged individuals (mean age 53 years [SD 7]) and 99 668 incident cases of fatal and non-fatal CVD events over a median follow-up of 6·5 years (IQR 5·0-10·2). NAFLD was associated with a moderately increased risk of fatal or non-fatal CVD events (pooled random-effects HR 1·45, 95% CI 1·31-1·61; I²=86·18%). This risk markedly increased across the severity of NAFLD, especially the stage of fibrosis (pooled random-effects HR 2·50, 95% CI 1·68-3·72; I²=73·84%). All risks were independent of age, sex, adiposity measures, diabetes, and other common cardiometabolic risk factors. Sensitivity analyses did not modify these results.

INTERPRETATION

NAFLD is associated with an increased long-term risk of fatal or non-fatal CVD events. CVD risk is further increased with more advanced liver disease, especially with higher fibrosis stage. These results provide evidence that NAFLD might be an independent risk factor for CVD morbidity and mortality.

FUNDING

None.

Risk of Cardiovascular Disease in Individuals With Nonobese Nonalcoholic Fatty Liver Disease

Nonalcoholic fatty liver disease (NAFLD) is independently associated with obesity and cardiovascular disease (CVD). CVD is the primary cause of mortality in the predominantly obese population of adults with NAFLD. NAFLD is increasingly seen in individuals who are lean and overweight (i.e., nonobese), but it is unclear whether their risk of CVD is comparable to those with NAFLD and obesity. Using a prospective cohort of patients with NAFLD, we compared the prevalence and incidence of CVD in individuals with and without obesity. NAFLD was diagnosed by biopsy or imaging after excluding other chronic liver disease etiologies. Logistic regression was used to compare the odds of baseline CVD by obesity status. Cox proportional hazards regression was used to evaluate obesity as a predictor of incident CVD and to identify predictors of CVD in subjects with and without obesity. At baseline, adults with obesity had a higher prevalence of CVD compared to those without obesity (12.0% vs. 5.0%, P = 0.02). During follow-up, however, obesity did not predict incident CVD (hazard ratio [HR], 1.24; 95% confidence interval [CI], 0.69-2.22) or other metabolic diseases. Findings were consistent when considering body mass index as a continuous variable and after excluding subjects who were overweight. Age (adjusted HR [aHR], 1.05; 95% CI, 1.03-1.08), smoking (aHR, 4.61; 95% CI, 1.89-11.22), and decreased low-density lipoprotein levels (aHR, 0.98; 95% CI, 0.96-1.00) independently predicted incident CVD in the entire cohort, in subjects with obesity, and in those without obesity, respectively. Conclusion: Individuals with overweight or lean NAFLD are not protected from incident CVD compared to those with NAFLD and obesity, although CVD predictors appear to vary between these groups. Patients without obesity also should undergo rigorous risk stratification and treatment.

Mitochondria Matter: Systemic Aspects of Nonalcoholic Fatty Liver Disease (NAFLD) and Diagnostic Assessment of Liver Function by Stable Isotope Dynamic Breath Tests

The liver plays a key role in systemic metabolic processes, which include detoxification, synthesis, storage, and export of carbohydrates, lipids, and proteins. The raising trends of obesity and metabolic disorders worldwide is often associated with the nonalcoholic fatty liver disease (NAFLD), which has become the most frequent type of chronic liver disorder with risk of progression to cirrhosis and hepatocellular carcinoma. Liver mitochondria play a key role in degrading the pathways of carbohydrates, proteins, lipids, and xenobiotics, and to provide energy for the body cells. The morphological and functional integrity of mitochondria guarantee the proper functioning of β-oxidation of free fatty acids and of the tricarboxylic acid cycle. Evaluation of the liver in clinical medicine needs to be accurate in NAFLD patients and includes history, physical exam, imaging, and laboratory assays. Evaluation of mitochondrial function in chronic liver disease and NAFLD is now possible by novel diagnostic tools. "Dynamic" liver function tests include the breath test (BT) based on the use of substrates marked with the non-radioactive, naturally occurring stable isotope 13C. Hepatocellular metabolization of the substrate will generate 13CO2, which is excreted in breath and measured by mass spectrometry or infrared spectroscopy. Breath levels of 13CO2 are biomarkers of specific metabolic processes occurring in the hepatocyte cytosol, microsomes, and mitochondria. 13C-BTs explore distinct chronic liver diseases including simple liver steatosis, non-alcoholic steatohepatitis, liver fibrosis, cirrhosis, hepatocellular carcinoma, drug, and alcohol effects. In NAFLD, 13C-BT use substrates such as α-ketoisocaproic acid, methionine, and octanoic acid to assess mitochondrial oxidation capacity which can be impaired at an early stage of disease. 13C-BTs represent an indirect, cost-effective, and easy method to evaluate dynamic liver function. Further applications are expected in clinical medicine. In this review, we discuss the involvement of liver mitochondria in the progression of NAFLD, together with the role of 13C-BT in assessing mitochondrial function and its potential use in the prevention and management of NAFLD.

Mechanisms and disease consequences of nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) is the leading chronic liver disease worldwide. Its more advanced subtype, nonalcoholic steatohepatitis (NASH), connotes progressive liver injury that can lead to cirrhosis and hepatocellular carcinoma. Here we provide an in-depth discussion of the underlying pathogenetic mechanisms that lead to progressive liver injury, including the metabolic origins of NAFLD, the effect of NAFLD on hepatic glucose and lipid metabolism, bile acid toxicity, macrophage dysfunction, and hepatic stellate cell activation, and consider the role of genetic, epigenetic, and environmental factors that promote fibrosis progression and risk of hepatocellular carcinoma in NASH.