Fasting insulin and uric acid levels but not indices of iron metabolism are independent predictors of non-alcoholic fatty liver disease. A case-control study

Associations of serum uric acid levels and anthropometric parameters with non-alcoholic fatty liver disease in healthy individuals: innovative insights from a cross-sectional study

OBJECTIVE

Non-alcoholic fatty liver disease (NAFLD is a spectrum of liver disease with a rising prevalence, ranging from simple steatosis to steatohepatitis and cirrhosis, where a significant minority face potential complications. Determining the predictive markers plays a crucial role. This study examined the relationship between serum uric acid (SUA) levels and NAFLD in healthy individuals and identified potential other predictors.

MATERIAL AND METHODS

A cohort of 2162 healthy participants attending routine check-up visits between February 2021 and May 2023 were included. Participants underwent abdominal ultrasound, uric acid measurements, and anthropometric assessments by TANITA. NAFLD was graded using a "hepatic steatosis score." Statistical analysis included nonparametric tests, chi-squared tests, Fisher's exact test, ROC curve analysis, and logistic regression.

RESULTS

The median age was 45 years (range:18-65). 1017 were male, and 1145 were female. Among the participants, 53.9%, 26.3%, 17.9%, and 1.9% exhibited Grade 0, 1, 2, and 3 hepatic steatosis, respectively. ROC analysis showed 80.0% sensitivity and 78.8% specificity for detecting grade 2 or higher hepatic steatosis with a cutoff value of 5.21 mg/dl of SUA (AUC = 0.82, p < 0.001, 95%CI 0.79-0.84). There were significant associations between elevated uric acid levels and NAFLD. Participants with higher body fat percentages, BMI values, and waist-to-hip ratios also demonstrated an increased prevalence of steatosis. Gender significantly influenced liver steatosis, with males exhibiting higher grades compared to females. Logistic regression analysis highlighted positive associations between NAFLD and body fat percentage, waist-to-hip ratio, and uric acid levels. Each unit increase in uric acid levels corresponded to a 2.5-fold increase in the odds of NAFLD (p < 0.001, 95% CI = 2.20-2.84).

CONCLUSION

Our findings suggest a significant relationship between serum uric acid levels and NAFLD in healthy individuals. Elevated uric acid levels, in conjunction with other anthropometric parameters, may serve as potential predictive markers for NAFLD.

Liver Fat Scores for Noninvasive Diagnosis and Monitoring of Nonalcoholic Fatty Liver Disease in Epidemiological and Clinical Studies

Nonalcoholic fatty liver disease (NAFLD) is strongly associated with the metabolic syndrome and type 2 diabetes and independently contributes to long-term complications. Being often asymptomatic but reversible, it would require population-wide screening, but direct diagnostics are either too invasive (liver biopsy), costly (MRI) or depending on the examiner's expertise (ultrasonography). Hepatosteatosis is usually accommodated by features of the metabolic syndrome (e.g. obesity, disturbances in triglyceride and glucose metabolism), and signs of hepatocellular damage, all of which are reflected by biomarkers, which poorly predict NAFLD as single item, but provide a cheap diagnostic alternative when integrated into composite liver fat indices. Fatty liver index, NAFLD LFS, and hepatic steatosis index are common and accurate indices for NAFLD prediction, but show limited accuracy for liver fat quantification. Other indices are rarely used. Hepatic fibrosis scores are commonly used in clinical practice, but their mandatory reflection of fibrotic reorganization, hepatic injury or systemic sequelae reduces sensitivity for the diagnosis of simple steatosis. Diet-induced liver fat changes are poorly reflected by liver fat indices, depending on the intervention and its specific impact of weight loss on NAFLD. This limited validity in longitudinal settings stimulates research for new equations. Adipokines, hepatokines, markers of cellular integrity, genetic variants but also simple and inexpensive routine parameters might be potential components. Currently, liver fat indices lack precision for NAFLD prediction or monitoring in individual patients, but in large cohorts they may substitute nonexistent imaging data and serve as a compound biomarker of metabolic syndrome and its cardiometabolic sequelae.

Expanding Pharmacists' Role in the Management of Non-Alcoholic Fatty Liver Disease

Non-alcoholic fatty liver disease (NAFLD) stands as an increasingly pressing global health challenge, underscoring the need for timely identification to facilitate effective treatment and prevent the progression of chronic liver disorders. Given the projected scarcity of specialized healthcare professionals, particularly hepatologists and gastroenterologists, the role of pharmacists emerges as pivotal in NAFLD management. This article sheds light on the potential of pharmacists within community pharmacy settings, not as diagnostic entities, but as facilitators in recognizing and screening individuals at elevated NAFLD risk using validated non-invasive tools like portable devices and calculators. By prioritizing patient education, referrals, and continuous monitoring, pharmacists can refine NAFLD management, ultimately advancing patient outcomes. Enhancing pharmacists' impact in early NAFLD detection and management can be facilitated through collaborations with healthcare institutions and the incorporation of patient self-assessment tools. This collaborative approach holds promise for further promoting improved liver health within the community.

A dynamic machine learning model for prediction of NAFLD in a health checkup population: A longitudinal study

Background

Non-alcoholic fatty liver disease (NAFLD) is one of the most common liver diseases worldwide. Currently, most NAFLD prediction models are diagnostic models based on cross-sectional data, which failed to provide early identification or clarify causal relationships. We aimed to use time-series deep learning models with longitudinal health checkup records to predict the onset of NAFLD in the future, and update the model stepwise by incorporating new checkup records to achieve dynamic prediction.

Methods

10,493 participants with over 6 health checkup records from Beijing MJ Health Screening Center were included to conduct a retrospective cohort study, in which the constantly updated initial 5 checkup data were incorporated stepwise to predict the risk of NAFLD at and after their sixth health checkups. A total of 33 variables were considered, consisting of demographic characteristics, medical history, lifestyle, physical examinations, and laboratory tests. L1-penalized logistic regression (LR) was used for feature selection. The long short-term memory (LSTM) algorithm was introduced for model development, and five-fold cross-validation was conducted to tune and choose optimal hyperparameters. Both internal validation and external validation were conducted, using the 20% randomly divided holdout test dataset and previously unseen data from Shanghai MJ Health Screening Center, respectively, to evaluate model performance. The evaluation metrics included area under the receiver operating characteristic curve (AUROC), sensitivity, specificity, Brier score, and decision curve. Bootstrap sampling was implemented to generate 95% confidence intervals of all the metrics. Finally, the Shapley additive explanations (SHAP) algorithm was applied in the holdout test dataset for model interpretability to obtain time-specific and sample-specific contributions of each feature.

Results

Among the 10,493 participants, 1662 (15.84%) were diagnosed with NAFLD at and after their sixth health checkups. The predictive performance of the deep learning model in the internal validation dataset improved over the incorporation of the checkups, with AUROC increasing from 0.729 (95% CI: 0.698,0.760) at baseline to 0.818 (95% CI: 0.798,0.844) when consecutive 5 checkups were included. The external validation dataset, containing 1728 participants, was used to verify the results, in which AUROC increased from 0.700 (95% CI: 0.657,0.740) with only the first checkups to 0.792 (95% CI: 0.758,0.825) with all five. The results of feature significance showed that body fat percentage, alanine transaminase (ALT), and uric acid owned the greatest impact on the outcome, time-specific, individual-specific and dynamic feature contributions were also produced for model interpretability.

Conclusion

A dynamic prediction model was successfully established in our study, and the prediction capability kept improving with the renewal of the latest checkup records. In addition, we identified key features associated with the onset of NAFLD, making it possible to optimize the prevention and control strategies of the disease in the general population.

Association of serum uric acid-to-high-density lipoprotein cholesterol ratio with non-alcoholic fatty liver disease in American adults: a population-based analysis

Objective

Non-invasive disease indicators are currently limited and need further research due to the increased non-alcoholic fatty liver disease (NAFLD) prevalence worldwide. The serum uric acid-to-high-density lipoprotein cholesterol ratio (UHR) has been recognized as a novel inflammatory and metabolic marker. Herein, we explored the correlation between UHR and the risk of NAFLD in-depth.

Methods

A total of 3,766 participants were included in our survey, and the National Health and Nutrition Examination Survey (NHANES) 2017-2018 cycle provided the cross-sectional study population. Weighted multivariable logistic regression and multivariate linear regression analyses were performed to assess the association between the UHR and the odds of NAFLD and liver steatosis and fibrosis severity, respectively. Moreover, we explored the non-linear relationship between the UHR and NAFLD by the generalized additive model.

Results

NAFLD probabilities were statistically demonstrated to be positively correlated with the UHR (OR = 1.331 per SD increase, 95% CI: 1.100, 1.611). The positive connection of the UHR with NAFLD risk persisted significantly in female subjects but not in male subjects in subgroup analyses stratified by gender. The non-linear relationship analysis demonstrated that a UHR between ~20 and 30% suggested a saturation effect of NAFLD risk. Furthermore, a dramatically positive correlation was found between the UHR and hepatic steatosis severity but not fibrosis. Finally, the receiver operating characteristic analysis suggested that UHR had a better predictive value for NAFLD than either serum uric acid (sUA) or high-density lipoprotein cholesterol (HDL) alone [UHR (area under curve): 0.6910; 95% CI: 0.6737-0.7083; P < 0.0001].

Conclusion

Our investigation revealed that the elevated UHR level was independently related to an increased NAFLD risk and the severity of liver steatosis in American individuals. The correlation differed according to sex. This non-invasive indicator may enhance the capacity to predict the onset of NAFLD and may uncover alternative therapeutic interventional targets.

Beneficial effects of luseogliflozin on lipid profile and liver function in patients with type 2 diabetes mellitus (BLUE trial): a single-center, single-arm, open-label prospective study

BACKGROUND

Arteriosclerosis and non-alcoholic fatty liver disease are major complications of diabetes mellitus. Hyperglycemia, insulin resistance, obesity, and metabolic syndrome are associated with the progression of these complications. Sodium-glucose transporter 2 inhibitors such as luseogliflozin are oral hypoglycemic agents that reduce glucose levels, induce loss of weight or body fat, and improve liver function. However, the effects of these agents on lipid profiles are unclear. Therefore, this study aimed to investigate these effects and their relationship with arteriosclerosis and non-alcoholic fatty liver disease.

METHODS

This single-center, single-arm, open-labeled prospective study enrolled 25 outpatients with type 2 diabetes mellitus who visited Minami Osaka Hospital. Laboratory tests and body measurements were performed at weeks 0 and 24. Luseogliflozin was started at 2.5 mg/day after breakfast, and data from weeks 0 and 24 were evaluated. There were no changes in the doses of other antidiabetic and dyslipidemia drugs a month prior to or during the study.

RESULTS

The patients showed significant reductions in the levels of triglycerides, remnant-like particle cholesterol, and triglyceride/high-density lipoprotein cholesterol ratio, along with significant increases in the levels of high-density lipoprotein cholesterol and apolipoprotein A-1. Alanine aminotransferase, γ-glutamyl transpeptidase, and the fatty liver index were significantly reduced.

CONCLUSIONS

Luseogliflozin-induced changes in the lipid profile were related to the suppression or improvement of arteriosclerosis and liver function, respectively. Patients who received this drug also showed improvements in the levels of liver enzymes and reductions in the fatty liver index. Earlier use of luseogliflozin might prevent diabetic complications. Trial registration This study was registered in the University Hospital Medical Information Network Clinical Trial Registry (UMIN 000043595) on April 6th, 2021.

Obese female mice do not exhibit overt hyperuricemia despite hepatic steatosis and impaired glucose tolerance

Recent reports have clearly demonstrated a tight correlation between obesity and elevated circulating uric acid levels (hyperuricemia). However, nearly all preclinical work in this area has been completed with male mice, leaving the field with a considerable gap in knowledge regarding female responses to obesity and hyperuricemia. This deficiency in sex as a biological variable extends beyond unknowns regarding uric acid (UA) to several important comorbidities associated with obesity including nonalcoholic fatty liver disease (NAFLD). To attempt to address this issue, herein we describe both phenotypic and metabolic responses to diet-induced obesity (DIO) in female mice. Six-week-old female C57BL/6J mice were fed a high-fat diet (60% calories derived from fat) for 32 weeks. The DIO female mice had significant weight gain over the course of the study, higher fasting blood glucose, impaired glucose tolerance, and elevated plasma insulin levels compared to age-matched on normal chow. While these classic indices of DIO and NAFLD were observed such as increased circulating levels of ALT and AST, there was no difference in circulating UA levels. Obese female mice also demonstrated increased hepatic triglyceride (TG), cholesterol, and cholesteryl ester. In addition, several markers of hepatic inflammation were significantly increased. Also, alterations in the expression of redox-related enzymes were observed in obese mice compared to lean controls including increases in extracellular superoxide dismutase (Sod3), heme oxygenase (Ho)-1, and xanthine dehydrogenase (Xdh). Interestingly, hepatic UA levels were significantly elevated (~2-fold) in obese mice compared to their lean counterparts. These data demonstrate female mice assume a similar metabolic profile to that reported in several male models of obesity in the context of alterations in glucose tolerance, hepatic steatosis, and elevated transaminases (ALT and AST) in the absence of hyperuricemia affirming the need for further study.

Clinical and Metabolic Characteristics of Hyperuricemia with Risk of Liver Fibrosis: A Cross-Sectional Study

The role of serum uric acid (SUA) in the role of advanced fibrosis is not fully explored. The study assesses the risk of advanced fibrosis according to SUA in an Asian population with a total of 3612 subjects enrolled in one health management center between 2006 and 2008. The fibrosis-4 score was used for the prediction of the high risk of advanced fibrosis. SUA scores higher than 7.6 mg/dL in men and 6.6 mg/dL in women were defined as hyperuricemia. A proportional odds model was used to assess cumulative risks of advanced fibrosis. The prevalence of high risk of advanced fibrosis was 2.5% in the hyperuricemia group and 0.6% in the normal SUA group (p < 0.001). After adjustment for confounding factors, the odds ratios (OR) for more severe advanced fibrosis were 1.37 (95% confidence interval [CI]: 1.07−1.78) in the hyperuricemia group. Hyperuricemia only increased the risk of advanced fibrosis in the non-T2DM group (OR, 1.29; 95% CI, 1.04 to 1.74) instead of T2DM group (OR, 1.85; 95% CI, 0.97 to 3.53). SUA is a risk factor for a higher risk of advanced fibrosis, with the disease likely progressing from a steatotic to a fibrotic picture. The focus should be more emphasized in non-T2DM groups.

Benefits of Physical Exercise as Approach to Prevention and Reversion of Non-Alcoholic Fatty Liver Disease in Children and Adolescents with Obesity

Non-alcoholic fatty liver disease (NAFLD) is an important health concern during childhood; indeed, it is the most frequent cause of chronic liver diseases in obese children. No valid pharmacological therapies for children affected by this condition are available, and the recommended treatment is lifestyle modification, usually including nutrition and exercise interventions. In this narrative review, we summarized up-to-date information on the benefits of physical exercise on NAFLD in children and adolescents with obesity. The role of exercise as non-pharmacological treatment was emphasized in order to provide recent advances on this topic for clinicians not deeply involved in the field. Several studies on obese children and adults confirm the positive role of physical activity (PA) in the treatment of NAFLD, but to date, there are no pediatric randomized clinical trials on exercise versus usual care. Among the pathogenic mechanisms involved in the PA effects on NAFLD, the main players seem to be insulin resistance and related inflammation, oxidative stress, and gut dysbiosis, but further evaluations are necessary to deeply understand whether these factors are correlated and how they synergistically act. Thus, a deeper research on this theme is needed, and it would be extremely interesting.

Conjunctional Relationship between Serum Uric Acid and Serum Nickel with Non-Alcoholic Fatty Liver Disease in Men: A Cross-Sectional Study

Serum uric acid (SUA) and heavy metals are closely related to non-alcoholic fatty liver disease (NAFLD). Yet, the conjunctional relationship between SUA and serum nickel (Ni) concentrations with the risk of NAFLD in men has not yet been investigated. Therefore, we designed this cross-sectional study to investigate the association of SUA or serum Ni with NAFLD in men. The cross-sectional study was based on data obtained from a prospective cohort study of common chronic non-communicable diseases in Central China, conducted in Xinxiang city, Central China's Henan Province, between April and June 2017. A total of 1709 male participants completed the physical examination. B-ultrasound was used to examine the liver and to diagnose NAFLD. Binary logistic regression models and restricted cubic splines were performed to estimate the association of the SUA and serum Ni with NAFLD. The prevalence of NAFLD among 1709 male participants was 46.6%. After adjusting for potential confounders, with the highest quartile compared to those with the lowest quartile, SUA (OR = 1.579, 95% CI: 1.140-2.189) and serum Ni (OR = 1.896, 95% CI: 1.372-2.625) were associated with NAFLD, respectively. At the same time, the associations for the second and third SUA quartiles were null. Restricted cubic splines showed a positive linear relationship between serum Ni (ln-transformed) and NAFLD risk. Intriguingly, high SUA and high Ni (OR = 2.370, 95% CI: 1.577-3.597) increased the risk of NAFLD, compared with those with low SUA and low Ni. Our findings demonstrate a positive linear trend between serum Ni concentrations and NAFLD risk. Men with elevated serum Ni had a higher risk of developing NAFLD when compared to those with high SUA. Furthermore, the conjunctional relationship of SUA and serum Ni with NAFLD risk was observed in men.

Higher serum uric acid to HDL-cholesterol ratio is associated with onset of non-alcoholic fatty liver disease in a non-obese Chinese population with normal blood lipid levels

BACKGROUND

Recent studies have demonstrated the presence of associations between metabolic syndrome and the onset of nonalcoholic fatty liver disease (NAFLD). Metabolic syndrome, in turn, has been found to be linked to high serum uric acid to HDL-cholesterol ratios (UHR). However, the relationship between UHR values and the occurrence of NAFLD in non-obese individuals remains unknown. The present study aimed to examine the possible correlation between UHR values and NAFLD onset among a non-obese Chinese population without dyslipidemia, as well as comparing the predictive value of UHR versus other NAFLD onset predictors.

METHODS

A total of 9837 non-obese patients, with normal blood lipid levels, were included in a 5-year retrospective cohort study, and the onset of NAFLD in these patients was diagnosed by liver ultrasound.

RESULTS

Out of the 9837 patients, 855 were diagnosed with NAFLD during the 5-year follow-up period, for an overall total prevalence of 8.7% at the end of the study period. Across quintiles 1, 2, 3, 4 and 5 of UHR (respectively, ratios of ≤ 120.88, 120.89-154.01, 154.02-189.91, 189.92-240.46, and ≥ 240.47), the prevalence of NAFLD among the patients increased from 2.4%, 5%, 7.9%, 10.3%, and 17.8%, respectively. After adjustments for age, gender, liver and kidney functional markers, as well as metabolic indicators, multivariate Cox proportional hazard regression analysis demonstrated that the hazard ratio (HR) was the highest in quintile 5, at 1.76 (1.12-2.75), and the lowest in quintile 1. The area under the curve (AUC) for UHR (0.690) was higher than that for serum uric acid (UA, 0.666) and HDL-C (0.636), suggesting the predictive ability of UHR for NAFLD onset was better than either alone. This finding was further supported by the presence of an independent association between UHR and NAFLD, even within the normal range of UA and HDL-C; the HR (95% confidence interval, CI) for NAFLD was 1.002 (1.000-1.004). Compared with other significant predictors, AUC for UHR (0.67) was similar to that of low-density lipoprotein cholesterol (LDL-C)/high-density lipoprotein cholesterol (HDL-C, 0.68), non-high-density lipoprotein cholesterol (NHDL-C)/HDL-C (0.68) and alanine aminotransferase (ALT)/aspartate aminotransferase (AST) ratios (0.7), and was higher than that of LDL-C (0.63), remnant cholesterol (RC,0.59), and albumin (ALB)/alkaline phosphatase (ALP) ratio (0.61). The sensitivity of UHR (71%) was the highest among all indicators. In the subgroup with ALT < 40U/L, the AUC for UHR was 0.70, which was the highest among all predictors; among ALT > 40U/L, UHR was able to predict the occurrence of NAFLD (AUC = 0.61, p = 0.007), which was not the case for RC (P = 0.441), ALB/ALP (P = 0.419), and ALT/AST (P = 0.159).

CONCLUSIONS

UHR serve as an inexpensive and reliable predictor of NAFLD onset in non-obese Chinese people with normal blood lipid levels, allowing for identification of individuals at high risk for NAFLD.

The National Consensus statement on the management of adult patients with non-alcoholic fatty liver disease and main comorbidities

The National Consensus was prepared with the participation of the National Medical Association for the Study of the Multimorbidity, Russian Scientific Liver Society, Russian Association of Endocrinologists, Russian Association of Gerontologists and Geriatricians, National Society for Preventive Cardiology, Professional Foundation for the Promotion of Medicine Fund PROFMEDFORUM. The aim of the multidisciplinary consensus is a detailed analysis of the course of non-alcoholic fatty liver disease (NAFLD) and the main associated conditions. The definition of NAFLD is given, its prevalence is described, methods for diagnosing its components such as steatosis, inflammation and fibrosis are described. The association of NAFLD with a number of cardio-metabolic diseases (arterial hypertension, atherosclerosis, thrombotic complications, type 2 diabetes mellitus (T2DM), obesity, dyslipidemia, etc.), chronic kidney disease (CKD) and the risk of developing hepatocellular cancer (HCC) were analyzed. The review of non-drug methods of treatment of NAFLD and modern opportunities of pharmacotherapy are presented. The possibilities of new molecules in the treatment of NAFLD are considered: agonists of nuclear receptors, antagonists of pro-inflammatory molecules, etc. The positive properties and disadvantages of currently used drugs (vitamin E, thiazolidinediones, etc.) are described. Special attention is paid to the multi-target ursodeoxycholic acid (UDCA) molecule in the complex treatment of NAFLD as a multifactorial disease. Its anti-inflammatory, anti-oxidant and cytoprotective properties, the ability to reduce steatosis an independent risk factor for the development of cardiovascular pathology, reduce inflammation and hepatic fibrosis through the modulation of autophagy are considered. The ability of UDCA to influence glucose and lipid homeostasis and to have an anticarcinogenic effect has been demonstrated. The Consensus statement has advanced provisions for practitioners to optimize the diagnosis and treatment of NAFLD and related common pathogenetic links of cardio-metabolic diseases.

Serum iron is closely associated with metabolic dysfunction-associated fatty liver disease in type 2 diabetes: A real-world study

AIMS

There is still a debate about the relationship between serum iron and metabolic dysfunction-associated fatty liver disease (MAFLD). Furthermore, few relevant studies were conducted in type 2 diabetes mellitus (T2DM). Therefore, this study aimed to explore the association of serum iron levels with MAFLD in Chinese patients with T2DM.

METHODS

This cross-sectional, real-world study consisted of 1,467 Chinese T2DM patients. MAFLD was diagnosed by abdominal ultrasonography. Based on serum iron quartiles, the patients were classified into four groups. Clinical characteristics were compared among the four groups, and binary logistic analyses were used to assess the associations of serum iron levels and quartiles with the presence of MAFLD in T2DM.

RESULTS

After adjusting for gender, age, and diabetes duration, significantly higher prevalence of MAFLD was found in the second (45.7%), third (45.2%), and fourth (47.0%) serum iron quartiles than in the first quartiles (26.8%), with the highest MAFLD prevalence in the fourth quartile (p < 0.001 for trend). Moreover, increased HOMA2-IR (p = 0.003 for trend) and decreased HOMA2-S (p = 0.003 for trend) were observed across the serum iron quartiles. Fully adjusted binary logistic regression analyses indicated that both increased serum iron levels (OR: 1.725, 95% CI: 1.427 to 2.085, p < 0.001) and quartiles (p < 0.001 for trend) were still closely associated with the presence of MAFLD in T2DM patients even after controlling for multiple confounding factors.

CONCLUSIONS

There is a positive correlation between the presence of MAFLD and serum iron levels in T2DM patients, which may be attributed to the close association between serum iron and insulin resistance. Serum iron levels may act as one of the indicators for evaluating the risk of MAFLD in T2DM individuals.

Serum lipids are associated with nonalcoholic fatty liver disease: a pilot case-control study in Mexico

Background

Nonalcoholic fatty liver disease (NAFLD) is a leading cause of chronic liver disease and cirrhosis. NAFLD is mediated by changes in lipid metabolism and known risk factors include obesity, metabolic syndrome, and diabetes. The aim of this study was to better understand differences in the lipid composition of individuals with NAFLD compared to controls, by performing direct infusion lipidomics on serum biospecimens from a cohort study of adults in Mexico.

Methods

A nested case-control study was conducted with a sample of 98 NAFLD cases and 100 healthy controls who are participating in an on-going, longitudinal study in Mexico. NAFLD cases were clinically confirmed using elevated liver enzyme tests and liver ultrasound or liver ultrasound elastography, after excluding alcohol abuse, and 100 controls were identified as having at least two consecutive normal alanine aminotransferase (ALT) and aspartate aminotransferase (AST) (< 40 U/L) results in a 6-month period, and a normal liver ultrasound elastography result in January 2018. Samples were analyzed on the Sciex Lipidyzer Platform and quantified with normalization to serum volume. As many as 1100 lipid species can be identified using the Lipidyzer targeted multiple-reaction monitoring list. The association between serum lipids and NAFLD was investigated using analysis of covariance, random forest analysis, and by generating receiver operator characteristic (ROC) curves.

Results

NAFLD cases had differences in total amounts of serum cholesterol esters, lysophosphatidylcholines, sphingomyelins, and triacylglycerols (TAGs), however, other lipid subclasses were similar to controls. Analysis of individual TAG species revealed increased incorporation of saturated fatty acyl tails in serum of NAFLD cases. After adjusting for age, sex, body mass index, and PNPLA3 genotype, a combined panel of ten lipids predicted case or control status better than an area under the ROC curve of 0.83.

Conclusions

These preliminary results indicate that the serum lipidome differs in patients with NAFLD, compared to healthy controls, and suggest that assessing the desaturation state of TAGs or a specific lipid panel may be useful clinical tools for the diagnosis of NAFLD.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12944-021-01526-5.

A correlation study of the relationships between nonalcoholic fatty liver disease and serum triglyceride concentration after an oral fat tolerance test

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) has become one of the most common chronic liver diseases worldwide. Triglyceride (TG) accumulation is central to NAFLD development. People now spend most of their day in the postprandial state, and the measurement of postprandial blood lipid concentration can make up for the lack of simple detection of fasting blood lipids. Postprandial triglyceride (PTG) is commonly used as a surrogate for postprandial blood lipid concentrations, and many studies have shown that PTG is a risk factor for NAFLD. The aim of the present study was to investigate the relationship between PTG concentration during oral fat tolerance testing (OFTT) and NAFLD.

METHODS

A total of 472 Chinese adults, aged 25 to 65 years, were enrolled in the study. All the participants underwent OFTT. The serum concentrations of TG and other lipids were measured, and their relationships with NAFLD were analyzed.

RESULTS

Of the 472 participants, 155 were diagnosed with NAFLD. The fasting and postprandial TG concentrations of the participants with NAFLD were higher than those of healthy participants (P < 0.05). The TG concentrations of the healthy participants peaked 4 h postprandially, whereas those of the participants with NAFLD peaked 6 h postprandially and reached higher peak values. Postprandial TG concentration was significantly associated with a higher risk of NAFLD.

CONCLUSIONS

High PTG is positively related to a higher risk of NAFLD, and the PTG concentrations of patients with NAFLD are higher than in healthy individuals, with a delayed peak. Therefore, 4-h PTG may represent a potential marker of NAFLD.

TRIAL REGISTRATION

ChiCTR1800019514 .

Association of the Serum Uric Acid-to-Creatinine Ratio with Nonalcoholic Fatty Liver Disease Diagnosed by Computed Tomography

Background: Although previous studies have suggested that the serum uric acid-to-creatinine ratio (sUA/Cr) is associated with metabolic syndrome, there is limited evidence of a relationship between sUA/Cr and nonalcoholic fatty liver disease (NAFLD). In this study, we investigated the association between sUA/Cr and NAFLD in healthy adults. Methods: A cross-sectional analysis was performed in 778 subjects who participated in a health examination. The participants were divided according to presence of NAFLD, which was determined by abdominal computed tomography (CT). Logistic regression analysis was performed to investigate the variables associated with NAFLD, and an adjusted odds ratio (OR) of sUA/Cr for NAFLD was estimated. Results: sUA/Cr in participants with NAFLD was significantly higher than in those without NAFLD. Multivariate analysis demonstrated significant association between sUA/Cr and NAFLD, and the adjusted OR of sUA/Cr increase of 1 for NAFLD was 1.182. (95% CI: 1.066-1.311). Conclusions: Elevated sUA/Cr was significantly associated with CT-diagnosed NAFLD in healthy adults. sUA/Cr may be a reliable marker for predicting NAFLD. (The Clinical Trial Registration number: 2020-06-002-002).

Ferritin as a key risk factor for nonalcoholic fatty liver disease in children with obesity

Background

The association between serum ferritin and nonalcoholic fatty liver disease (NAFLD) in children with obesity is not clear. This study was designed to investigate whether serum ferritin can be an independent predictor for NAFLD.

Methods

According to the hepatic ultrasound results, a total of 347 children with obesity were enrolled in this study. Among them, 95 patients with NAFLD and 95 without NAFLD were matched for gender, age, blood pressure and body mass index, the odds ratios (OR) and 95% confidence intervals (CI) for the association of ferritin and the risk of NAFLD were analyzed.

Results

After propensity score matching, ferritin values of the patients with NAFLD were significantly higher than those without NAFLD group. Alanine aminotransferase and ferritin were strongly associated with NAFLD in multivariate stepwise logistic regression analysis. The medium and high levels of ferritin increased risk of NAFLD, and the adjusted ORs were 3.298 (95% CI:1.326‐8.204), 7.322 (95% CI:2.725‐19.574) across the ferritin concentration tertiles after adjustment for confounders. Ferritin was shown to be the best predictor for NAFLD with sensitivity and specificity of 60.0% and 77.9%, respectively, area under the curve was 0.733.

Conclusion

The results show that serum ferritin can usefully be considered as a predictor of NAFLD in children with obesity.

History of Nonalcoholic Fatty Liver Disease

Based on the assumption that characterizing the history of a disease will help in improving practice while offering a clue to research, this article aims at reviewing the history of nonalcoholic fatty liver disease (NAFLD) in adults and children. To this end, we address the history of NAFLD histopathology, which begins in 1980 with Ludwig's seminal studies, although previous studies date back to the 19th century. Moreover, the principal milestones in the definition of genetic NAFLD are summarized. Next, a specific account is given of the evolution, over time, of our understanding of the association of NAFLD with metabolic syndrome, spanning from the outdated concept of "NAFLD as a manifestation of the Metabolic Syndrome", to the more appropriate consideration that NAFLD has, with metabolic syndrome, a mutual and bi-directional relationship. In addition, we also report on the evolution from first intuitions to more recent studies, supporting NAFLD as an independent risk factor for cardiovascular disease. This association probably has deep roots, going back to ancient Middle Eastern cultures, wherein the liver had a significance similar to that which the heart holds in contemporary society. Conversely, the notions that NAFLD is a forerunner of hepatocellular carcinoma and extra-hepatic cancers is definitely more modern. Interestingly, guidelines issued by hepatological societies have lagged behind the identification of NAFLD by decades. A comparative analysis of these documents defines both shared attitudes (e.g., ultrasonography and lifestyle changes as the first approaches) and diverging key points (e.g., the threshold of alcohol consumption, screening methods, optimal non-invasive assessment of liver fibrosis and drug treatment options). Finally, the principal historical steps in the general, cellular and molecular pathogenesis of NAFLD are reviewed. We conclude that an in-depth understanding of the history of the disease permits us to better comprehend the disease itself, as well as to anticipate the lines of development of future NAFLD research.

Perspectives of nonalcoholic fatty liver disease research: a personal point of view

Rational government of patient fluxes from primary care to hepatology clinic is a priority of nonalcoholic fatty liver disease (NAFLD) research. Estimating pre-test probability of disease, risk of fibrosis progression, and exclusion of competing causes of liver disease must be addressed. Here we propose a novel taxonomic classification of NAFLD based on hepatic, pathogenic and systemic features of disease in the individual patient. The variable course of disease in any given patient remains a clinical enigma. Therefore, future studies will have to better characterize the role of genetic polymorphisms, family and personal history, diet, alcohol, physical activity and drugs as modifiers of the course of disease and clues to the early diagnosis of hepatocellular carcinoma. A better understanding of these, together with a taxonomic diagnosis, may prompt a more accurate personalization of care. For example, understanding the putative role of psycho-depression in NAFLD promises to revolutionize disease management in a proportion of cases. Similarly, sex differences in outcome and response to treatment are insufficiently characterized. More studies are awaited regarding those forms of NAFLD which occur secondary to endocrine derangements. The intersections between NAFLD and the lung must better be defined. These include the bi-directional associations of NAFLD and chronic obstructive pulmonary disease and sleep apnoea syndrome, as well as the totally unexplored chapter of NAFLD and coronavirus disease 2019 (COVID-19). Finally, the therapeutic roles of intermittent fasting and anticoagulation must be assessed. In conclusion, over the last 20 years, NAFLD has taught us a lot regarding the pathogenic importance of insulin resistance, the limitations of correcting this in the treatment of NAFLD, the root causes of diabetes and the metabolic syndrome, sex differences in disease and the role of nuclear receptors. However, the overwhelming COVID-19 pandemic is now expected to reset the priorities of public health.

Perspectives of nonalcoholic fatty liver disease research: a personal point of view

Rational government of patient fluxes from primary care to hepatology clinic is a priority of nonalcoholic fatty liver disease (NAFLD) research. Estimating pre-test probability of disease, risk of fibrosis progression, and exclusion of competing causes of liver disease must be addressed. Here we propose a novel taxonomic classification of NAFLD based on hepatic, pathogenic and systemic features of disease in the individual patient. The variable course of disease in any given patient remains a clinical enigma. Therefore, future studies will have to better characterize the role of genetic polymorphisms, family and personal history, diet, alcohol, physical activity and drugs as modifiers of the course of disease and clues to the early diagnosis of hepatocellular carcinoma. A better understanding of these, together with a taxonomic diagnosis, may prompt a more accurate personalization of care. For example, understanding the putative role of psycho-depression in NAFLD promises to revolutionize disease management in a proportion of cases. Similarly, sex differences in outcome and response to treatment are insufficiently characterized. More studies are awaited regarding those forms of NAFLD which occur secondary to endocrine derangements. The intersections between NAFLD and the lung must better be defined. These include the bi-directional associations of NAFLD and chronic obstructive pulmonary disease and sleep apnoea syndrome, as well as the totally unexplored chapter of NAFLD and coronavirus disease 2019 (COVID-19). Finally, the therapeutic roles of intermittent fasting and anticoagulation must be assessed. In conclusion, over the last 20 years, NAFLD has taught us a lot regarding the pathogenic importance of insulin resistance, the limitations of correcting this in the treatment of NAFLD, the root causes of diabetes and the metabolic syndrome, sex differences in disease and the role of nuclear receptors. However, the overwhelming COVID-19 pandemic is now expected to reset the priorities of public health.

Sex differences in non-alcoholic fatty liver disease: hints for future management of the disease

Non-alcoholic fatty liver disease (NAFLD) remains a major cause of chronic liver disease worldwide. Despite extensive studies, the heterogeneity of the risk factors as well as different disease mechanisms complicate the goals toward effective diagnosis and management. Recently, it has been shown that sex differences play a role in the prevalence and progression of NAFLD. In vitro, in vivo, and clinical studies revealed that the lower prevalence of NAFLD in premenopausal as compared to postmenopausal women and men is mainly due to the protective effects of estrogen and body fat distribution. It has been also described that males and females present differential pathogenic features in terms of biochemical profiles and histological characteristics. However, the exact molecular mechanisms for the gender differences that exist in the pathogenesis of NAFLD are still elusive. Lipogenesis, oxidative stress, and inflammation play a key role in the progression of NAFLD. For NAFLD, only a few studies characterized these mechanisms at the molecular level. Therefore, we aim to review the reported differential molecular mechanisms that trigger such different pathogenesis in both sexes. Differences in lipid metabolism, glucose homeostasis, oxidative stress, inflammation, and fibrosis were discussed based on the evidence reported in recent publications. In conclusion, with this review, we hope to provide a new perspective for the development of future practice guidelines as well as a new avenue for the management of the disease.

Different predictors of steatosis and fibrosis severity among lean, overweight and obese patients with nonalcoholic fatty liver disease

BACKGROUNDS

Non-obese nonalcoholic fatty liver disease (NAFLD) is paradoxically associated with improved metabolic and pathological features at diagnosis but worse prognosis relative to obese NAFLD.

AIM

To compare predictors of disease severity in NAFLD with different body mass index (BMI) categories.

METHODS

All 1509 consecutive NAFLD patients were classified as lean (20.2%), overweight (23.1%) and obese (56.7%). Liver fat content (LFC) and fibrosis were estimated with magnetic resonance imaging-based proton density fat fraction and shear wave elastography respectively.

RESULTS

Lipid profiles and uric acid (UA) were significantly increased in parallel with BMI categories (pairwise comparison P < 0.001), but insulin resistance (IR) was significantly different between the non-obese and obese groups. For LFC ≥ 10%, increased waist circumference (WC) was an independent predictor in all groups, while UA elevation (P = 0.02) was predictive in the overweight patients, but BMI ≥ 28 kg/m² (P = 0.029) and IR (P = 0.026) were significant in the obese patients. For fibrosis, alanine aminotransferase (ALT) > 40 U/L (P = 0.031), increased WC (P = 0.012) and BMI ≥ 28 kg/m² (P < 0.001) plus ALT > 40 U/L (P = 0.007) were predictors in the lean, overweight and obese patients, respectively.

CONCLUSIONS

WC was strongly predictive of disease severity in all NAFLD, while UA and BMI plus IR were additional predictors in the overweight and obese NAFLD respectively. Individualized screening strategies should be established for NAFLD according to different BMIs.

Clinical characteristics of patients under 40 years old with early-onset hyperuricaemia: a retrospective monocentric study in China

OBJECTIVE

To investigate the clinical characteristics of patients with early-onset hyperuricaemia (HUC).

METHODS

A retrospective study using data from the Second Affiliated Hospital of Soochow University was conducted. 623 patients with HUC were divided into early-onset group and late-onset group. Another 201 healthy subjects ≤40 years old were regarded as control group. The data of physical measurements and biochemistry test were collected. Clinical data of early-onset group were compared with late-onset group and control group by analysis of variance (ANOVA) and χ² test. Principal component analysis (PCA) was applied. Logistic regression was used to identify the clinical factors correlated with patients with early-onset HUC.

RESULTS

The patients of early-onset group had different body mass index (BMI), serum albumin, alanine transaminase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (AKP), gamma-glutamyltransferase (GGT), creatinine (Cr), triglyceride (TG), total cholesterol (TC), low density lipoprotein (LDL), TG/high density lipoprotein (HDL) ratio, HDL and percentage of males, hypertension (HBP) as well as fatty liver compared with healthy people in the control group. Early-onset group patients had different albumin, ALT, fasting blood glucose, Cr, percentage of males and HBP compared with late-onset group patients. PCA identified four significant patterns including PC1 (labelled 'TG and HDL'), PC2 (labelled 'fatty liver and liver enzymes'), PC3 (labelled 'TC and LDL') and PC4 (labelled 'AKP'). The results of univariate and multivariate logistic regression analysis showed that BMI, HBP and albumin were correlative factors for early onset of HUC when the patients with early-onset and late-onset HUC were involved, while gender, BMI, PC1, PC2 and PC4 were correlative factors for early-onset HUC when the early-onset and control groups were involved.

CONCLUSION

This study described a group of patients with early-onset HUC with distinct clinical features. Gender, BMI, 'TG and HDL', 'fatty liver and liver enzymes' and 'AKP' have higher values than HBP, type 2 diabetes mellitus and 'TC and LDL' in patients under 40 years old with early-onset HUC.

Dietary Fructose and the Metabolic Syndrome

Consumption of fructose, the sweetest of all naturally occurring carbohydrates, has increased dramatically in the last 40 years and is today commonly used commercially in soft drinks, juice, and baked goods. These products comprise a large proportion of the modern diet, in particular in children, adolescents, and young adults. A large body of evidence associate consumption of fructose and other sugar-sweetened beverages with insulin resistance, intrahepatic lipid accumulation, and hypertriglyceridemia. In the long term, these risk factors may contribute to the development of type 2 diabetes and cardiovascular diseases. Fructose is absorbed in the small intestine and metabolized in the liver where it stimulates fructolysis, glycolysis, lipogenesis, and glucose production. This may result in hypertriglyceridemia and fatty liver. Therefore, understanding the mechanisms underlying intestinal and hepatic fructose metabolism is important. Here we review recent evidence linking excessive fructose consumption to health risk markers and development of components of the Metabolic Syndrome.

Gender effect of hyperuricemia on the development of nonalcoholic fatty liver disease (NAFLD): A clinical analysis and mechanistic study

BACKGROUND AND AIMS

Hyperuricemia is a risk factor for nonalcoholic fatty liver disease (NAFLD), however, the effect of gender on the hyperuricemia-related NAFLD development remains unclear. Here, we evaluated the clinical characteristics of NAFLD patients with hyperuricemia, and experimentally recapitulated this condition in male rats in order to gain insights on the possible impact of gender on the development of NAFLD in patients with hyperuricemia.

METHODS

The clinical characteristics of 238 NAFLD patients, together with the impacts of hyperuricemia on the major parameters related to the development of NALFD were analysed. In animal studies, NAFLD with hyperuricemia was induced in male SD rats using high-yeast high-fat diet containing potassium oxonate. The impact of uric acids on liver pathology, and the expression patterns of key molecules involved in the development of NAFLD, including silent information regulator 1 (SIRT1), nuclear factor kappa B subunit p65 (NF-κB p65), fork-head box class O-3a (FOXO3a), androgen receptor (AR), and xanthine oxidase (XO) were analysed.

RESULTS

Male NAFLD patients with hyperuricemia displayed more frequent and extensive liver injury than those in female patients. In male rats, hyperuricemia was associated with increased levels of insulin, alanine aminotransferase (ALT) and triglyceride (TG). At the molecular level, hyperuricemia was associated with decreased expression of SIRT1 and its phosphorylation, phosphorylation of FOXO3a, increased expression of AR and XO, and deacetylation of NF-κB P65.

CONCLUSIONS

Hyperuricemia is a compounding factor for NAFLD, particularly in males. The severer hepatic injury observed in male NAFLD patients may be attributed to the suppression of SIRT1 signalling induced by hyperuricemia.

The Liver in Children With Metabolic Syndrome

Non-alcoholic fatty liver disease (NAFLD) is recognized as an emerging health risk in obese children and adolescents. NAFLD represents a wide spectrum of liver conditions, ranging from asymptomatic steatosis to steatohepatitis. The growing prevalence of fatty liver disease in children is associated with an increased risk of metabolic and cardiovascular complications. NAFLD is considered the hepatic manifestation of Metabolic Syndrome (MetS) and several lines of evidence have reported that children with NAFLD present one or more features of MetS. The pathogenetic mechanisms explaining the interrelationships between fatty liver disease and MetS are not clearly understood. Altough central obesity and insulin resistance seem to represent the core of the pathophysiology in both diseases, genetic susceptibility and enviromental triggers are emerging as crucial components promoting the development of NAFLD and MetS in children. In the present review we have identified and summarizied studies discussing current pathogenetic data of the association between NAFLD and MetS in children.

Hypothyroidism and nonalcoholic fatty liver disease - a chance association?

Background Nonalcoholic fatty liver disease (NAFLD) defines the clinical-pathological spectrum of hepatic lipotoxicity, which may progress to hepatic fibrosis and its complications. Thyroid hormone is a master regulator of cell metabolism and body fat distribution. Whether hypothyroidism is associated or not with an increased risk of developing NAFLD and its fibrotic progression is both clinically and physiopathologically relevant. Indeed, answering this research question would carry major pathogenic and therapeutic implications. Method PubMed database was searched using relevant key-words such as hypothyroidism; NAFLD; nonalcoholic steatohepatitis; cirrhosis; hepatocellular carcinoma; epidemiology; pathogenesis; natural history. The epidemiological studies and the meta-analyses published so far were identified as well as those studies addressing the physiopathology underlying this association. Results Many observational studies have investigated the association between either subclinical or overt hypothyroidism and NAFLD. Data are conflicting: some original and meta-analytical studies demonstrated that hypothyroidism, (mainly subclinical hypothyroidism), was common, occurring in approximately 25% of individuals with imaging-defined or biopsy-proven NAFLD; other studies, however, failed to identify a significant association between hypothyroidism and NAFLD. Moreover, such an association is biologically plausible based on the specific physiopathological impact of thyroid hormone and thyroid stimulating hormone (TSH) on metabolism of hepatocytes and accumulation and distribution of body fat. Conclusions The findings from the present review support a significant association between primary hypothyroidism and risk of development and progression of NAFLD. However, further studies evaluating the relative importance of subclinical versus overt hypothyroidism as well as addressing the mechanisms underlying the association of hypothyroidism with NAFLD are eagerly awaited.

Joint associations of serum uric acid and ALT with NAFLD in elderly men and women: a Chinese cross-sectional study

Background

Epidemiological evidence suggests sex difference in serum uric acid (SUA) and alanine aminotransferase (ALT) might be a potential explanation for the gender difference in prevalence of non-alcoholic fatty liver disease (NAFLD). However, few epidemiology data in China have tested this hypothesis.

Methods

We conducted a cross-sectional study to assess the joint associations between SUA and serum ALT with NAFLD among elderly Chinese men and women.

Results

Among 7569 participants with a mean age of 59.8 years (± 13.4 years), 56.6% of women and 43.4% of men were diagnosed as NAFLD, respectively. A positive association between SUA and NAFLD prevalence was observed in both men and women. NAFLD prevalence was 2.74 times (95% CI 2.00–3.76) higher for men and 4.60 times (95% CI 3.39–6.24) higher for women with the highest quintiles of SUA levels compared to those with the lowest levels. SUA levels were significantly associated with prevalence of mild- and severe-steatosis (P < 0.01). In addition, the ORs of NAFLD among participants with high SUA levels and high serum ALT was 10.75 (95% CI 3.56–32.46) for men and 7.96 (95% CI 2.83–22.39) for women, compared with those with low SUA levels and low serum ALT.

Conclusions

SUA levels were positively associated with NAFLD prevalence, and the association was slightly stronger in women than in men. A significant joint association of SUA and serum ALT with NAFLD prevalence was observed in all participants, which was slightly stronger in men than in women.

Curcumin in Liver Diseases: A Systematic Review of the Cellular Mechanisms of Oxidative Stress and Clinical Perspective

Oxidative stress has been considered a key causing factor of liver damage induced by a variety of agents, including alcohol, drugs, viral infections, environmental pollutants and dietary components, which in turn results in progression of liver injury, non-alcoholic steatohepatitis, non-alcoholic liver disease, liver fibrosis and cirrhosis. During the past 30 years and even after the major progress in the liver disease management, millions of people worldwide still suffer from an acute or chronic liver condition. Curcumin is one of the most commonly used indigenous molecules endowed by various shielding functionalities that protects the liver. The aim of the present study is to comprehensively review pharmacological effects and molecular mechanisms, as well as clinical evidence, of curcumin as a lead compound in the prevention and treatment of oxidative associated liver diseases. For this purpose, electronic databases including “Scopus,” “PubMed,” “Science Direct” and “Cochrane library” were extensively searched with the keywords “curcumin or curcuminoids” and “hepatoprotective or hepatotoxicity or liver” along with “oxidative or oxidant.” Results showed that curcumin exerts remarkable protective and therapeutic effects of oxidative associated liver diseases through various cellular and molecular mechanisms. Those mechanisms include suppressing the proinflammatory cytokines, lipid perodixation products, PI3K/Akt and hepatic stellate cells activation, as well as ameliorating cellular responses to oxidative stress such as the expression of Nrf2, SOD, CAT, GSH, GPx and GR. Taking together, curcumin itself acts as a free radical scavenger over the activity of different kinds of ROS via its phenolic, β-diketone and methoxy group. Further clinical studies are still needed in order to recognize the structure-activity relationships and molecular mechanisms of curcumin in oxidative associated liver diseases.

Biochemical Predictors of Early Onset Non-Alcoholic Fatty Liver Disease in Young Children with Obesity

BACKGROUND

The prevalence of metabolic syndrome (MS) and non-alcoholic fatty liver disease (NAFLD) and their associated risk factors are not well-established in young children with obesity. The purpose of this study was to evaluate the prevalence of early onset NAFLD and identify its biochemical predictors in obese children aged less than 10 years.

METHODS

Anthropometric measurements, blood pressure, laboratory tests, and abdominal ultrasonography (USG) were performed in all subjects. National Cholesterol Education Program-Adult Treatment Panel III (NCEP-ATP III) criteria for MS diagnosis and liver enzymes and USG for NAFLD diagnosis were assessed.

RESULTS

A total of 356 children with obesity (233 boys, 123 girls) were included, with 172 children age ≤ 10 years and 184 adolescents. The prevalence of MS was 23.3% in young children and 35.3% in adolescents (P = 0.020); while the prevalence of NAFLD was 36.0% and 70.7%, respectively (P = 0.001). In obese children aged 10 years or less, there were significant differences in levels of serum γ-glutamyltranspeptidase (γGT) (P < 0.001), triglycerides (P = 0.042), and homeostatic model assessment of insulin resistance (P < 0.001) between the non-NAFLD and the NAFLD group. Multivariate logistic regression analysis revealed significant increase in serum γGT and uric acid levels in young children.

CONCLUSION

Although MS and NAFLD were more prevalent in adolescents, young children also demonstrated MS and NAFLD as obesity-related complications. Elevated serum γGT and uric acid levels may serve as biochemical predictors in detecting NAFLD in young children with obesity before investigation with abdominal USG.

Hyperuricaemia and risk of nonalcoholic fatty liver disease: A meta-analysis

BACKGROUND

The association between hyperuricaemia and nonalcoholic fatty liver disease (NAFLD), one of the leading causes of cirrhosis worldwide, has been demonstrated in recent epidemiological studies. This meta-analysis was conducted to summarize all available data and to estimate the risk of NAFLD among subjects with hyperuricaemia.

METHODS

Comprehensive literature review was conducted using MEDLINE and EMBASE database through August 2016 to identify studies that compared the risk of NAFLD among subjects with hyperuricaemia vs those with normal uric acid level. Effect estimates from individual study were extracted and combined together using random-effect, generic inverse variance method of DerSimonian and Laird.

RESULTS

Twenty-five studies met the eligibility criteria and were included in the meta-analysis. The risk of NAFLD in subjects with hyperuricaemia was significantly higher than subjects with normal uric acid level with the pooled odds ratio (OR) of 1.97 (95% confidence interval (CI), 1.69-2.29). The heterogeneity between studies of the overall analysis was high with an I² of 87%. Subgroup analysis based on 11 studies that provided data on males subgroup and nine studies that provided data on females subgroup showed that the risk was significantly increased for both sexes with pooled OR of 1.64 (95% CI, 1.40-1.93) among males and pooled OR of 2.21 (95% CI, 1.85-2.64) among females.

CONCLUSIONS

A significantly increased risk of NAFLD among patients with hyperuricaemia was demonstrated in this meta-analysis. Further studies are required to establish the role of uric acid in the pathogenesis of NAFLD.

Association between the hyperuricemia and nonalcoholic fatty liver disease risk in a Chinese population: A retrospective cohort study

Nonalcoholic fatty liver disease (NAFLD) is a common chronic disease associated with high levels of serum uric acid (SUA). However, whether this relationship applies in obese subjects has been unclear, and no cohort study has previously been conducted in non-obese subjects. We therefore performed a retrospective cohort study among employees of seven companies in China to investigate whether hyperuricemia was independently associated with NAFLD in obese and non-obese subjects, respectively. A total of 2383 initially NAFLD-free subjects were followed up for four years, and 15.2% (363/2383) developed NAFLD. Hyperuricemia subjects had a higher cumulative incidence than did those with normouricemia (29.0% vs. 12.9%, P<0.001). Cox proportional hazard regression analyses showed that baseline hyperuricemia was significantly associated with risk of developing NAFLD in non-obese subjects. This relationship was significantly independent of baseline age, gender, metabolic syndrome components, and other clinical variables (RR = 1.389, 95%CI: 1.051-2.099). However, this association did not exist in obese subjects (RR = 1.010, 95%CI: 0.649-1.571). The independent effect of hyperuricemia on NAFLD was stronger in females (RR = 2.138, 95%CI: 1.050-4.355) than in males (RR = 1.435, 95%CI: 1.021-2.018). In conclusion, further studies are needed to explore the different mechanisms between obese and non-obese subjects, and the reason hyperuricemia raises NAFLD risk in females more than in males.

Serum uric acid is independently and linearly associated with risk of nonalcoholic fatty liver disease in obese Chinese adults. Sci Rep. 2016;6:38605. [PMID: 27924915 PMCID: PMC5141483 DOI: 10.1038/srep38605]

The present study aimed to explore the independent association and potential pathways between serum uric acid (SUA) and nonalcoholic fatty liver disease (NAFLD). 1365 community-living obese Chinese adults who received hepatic ultrasonography scanning were included. The prevalence rates of NAFLD were 71.5% for men and 53.8% for women. Compared with controls, NAFLD subjects showed significantly increased SUA levels (333.3 ± 84.9 v.s. 383.4 ± 93.7 μmol/L) and prevalence rate of hyperuricemia (HUA) (25.7% v.s. 47.3%, p < 0.001). After adjustment for insulin resistance (IR), components of metabolic syndrome (MetS) and other potential confounders, elevated SUA is independently associated with increased risk of NAFLD, with the adjusted OR of 1.528–2.031 (p < 0.001). By using multivariable fractional polynomial (MFP) modeling, the best FP transformation model shows that SUA was independently and linearly associated with risk of NAFLD. The one-pathway model by using structural equation modeling (SEM) about the relationships among SUA, IR, components of metabolic syndrome and NAFLD fits well (χ² = 57.367, p < 0.001; CFI = 0.998; TLI = 0.992; and RMSEA = 0.048) and shows SUA might increase the risk of NAFLD directly besides of the indirect effects through increasing fasting insulin, blood pressure, triglyceride and decreasing HDL-C levels. Our results imply that elevated SUA may play an important role in NAFLD pathogenesis.

Associations between Serum Uric Acid and the Remission of Non-Alcoholic Fatty Liver Disease in Chinese Males

Epidemiological studies suggest that higher serum uric acid (sUA) level is significantly associated with nonalcoholic fatty liver disease (NAFLD) development. However, little information is available on the relationships between sUA and NAFLD remission. In the present study, 841 NAFLD males (30-75 years) were recruited from a Chinese prospective cohort study (PMMJS) and followed up for five years. The baseline sUA levels of participants were categorized into four quartiles: 191 μmol/L≤ sUA ≤ 347 μmol/L, 347 μmol/L < sUA ≤ 392 μmol/L, 392 μmol/L < sUA ≤ 441 μmol/L and 441 μmol/L<SUA≤676 μmol/L. As the results show, participants with elevated sUA levels at baseline were significantly associated with the decreased rate of NAFLD remission at the end of study (p<0.0001). After adjustment, RR (95%CI) for remitted NAFLD comparing Q1 to Q3 vs Q4 of sUA were 2.95 (1.49-5.83), 2.40 (1.22-4.73) and 1.39 (0.67-2.86), respectively. Furthermore, the sensitivity analysis showed these significant associations were not affected even after exclusion of participants who had hypertension, diabetes mellitus, MetS and hyperlipidemia. Additionally, the presence of the lowest quartile of sUA levels was still significantly associated with remitted NAFLD when the study population was stratified according to the smoking, and the median values of age, ALT, AST, serum creatinine, HDL-C and LDL-C. Therefore, our present study extended the previous findings and suggested that modulation of sUA levels may attenuate the progression of NAFLD.

The independent predictors of non-alcoholic steatohepatitis and its individual histological features.: Insulin resistance, serum uric acid, metabolic syndrome, alanine aminotransferase and serum total cholesterol are a clue to pathogenesis and candidate targets for treatment

AIM

The diagnosis of non-alcoholic steatohepatitis (NASH) is based on the individual histological features: steatosis, lobular inflammation and ballooning. Non-alcoholic fatty liver disease (NAFLD) activity score (NAS ≥ 5) is used in clinical trials. Fibrosis dictates long-term NAFLD prognosis. Recently, more-than-mild portal inflammation has raised interest as a marker of NAFLD severity. We assessed the independent predictors of: (I) individual histological lesions of NASH; (II) diagnosis of NASH; (III) significant (stage ≥2) and advanced (stage ≥3) fibrosis; and (IV) more-than-mild portal inflammation.

METHODS

Data from 118 consecutive biopsy-proven NAFLD patients observed at our institution were retrospectively analyzed.

RESULTS

At stepwise multivariate logistic regression analyses, independent predictors were as follows. For the individual histological features of NASH: insulin resistance (IR), assessed with Homeostasis Model Assessment-IR (HOMA-IR), serum uric acid (SUA) and serum total cholesterol (TCH) for moderate-to-severe steatosis; waist circumference (waist), HOMA-IR and TCH for lobular inflammation; waist, HOMA-IR, metabolic syndrome (MS), serum alanine aminotransferase (ALT), SUA and TCH for ballooning. For NASH diagnosis: waist, HOMA-IR, MS, ALT, SUA and TCH (Brunt et al.'s classification); ALT, SUA and TCH for NAS ≥ 5. For significant and advanced fibrosis, respectively: waist, MS and ALT; age, platelets, HOMA-IR, diabetes and TCH. For more-than-mild portal inflammation: serum aspartate aminotransferase (AST), serum iron, NAS ≥ 5 and significant liver fibrosis.

CONCLUSION

HOMA-IR, SUA, MS, ALT and TCH are independent predictors of NASH and its individual histological lesions, notably including fibrosis. Based on our findings, these factors should be considered major pathogenic drivers of NASH and, by inference, potential targets for treatment.

Association of Visceral Fat and Liver Fat With Hyperuricemia

OBJECTIVE

To examine cross-sectionally whether intraabdominal fat area (IAFA), i.e., visceral fat, and liver fat assessed by computed tomography (CT) are independently associated with hyperuricemia.

METHODS

Subjects were 801 Japanese men not taking antidiabetic, antihypertensive, or urate-lowering medications, without any history of renal disease, cardiovascular disease, or cancer, and with serum creatinine <1.5 mg/dl. Abdominal, thoracic, and thigh fat areas were measured by CT. Total fat area (TFA) was the sum of these fat areas. Total subcutaneous fat area (TSFA) was TFA minus IAFA. Liver fat was assessed by liver-to-spleen (L/S) ratio measured by CT. Hyperuricemia was defined as serum uric acid level >7.0 mg/dl. Its association with adiposity was tested using logistic regression.

RESULTS

The prevalence of hyperuricemia was 19.6% (157 men). Both greater IAFA and lower L/S ratio were independently associated with hyperuricemia in models that simultaneously included IAFA and L/S ratio: multiple-adjusted odds ratios of hyperuricemia for quintiles 3, 4, and 5 of IAFA were 2.16 (95% confidence interval [95% CI] 1.02-4.59), 2.41 (95% CI 1.13-5.16), and 4.00 (95% CI 1.81-8.85), respectively, compared to quintile 1, and the L/S ratios for quintiles 3, 2, and 1 were 2.34 (95% CI 1.16-4.75), 2.15 (95% CI 1.06-4.34), and 2.79 (95% CI 1.35-5.76), respectively, compared to quintile 5. Both IAFA and L/S ratio remained significant even after adjusting for abdominal subcutaneous fat area, TFA, TSFA, body mass index, or waist circumference. Of all fat measurements, IAFA had the strongest association with hyperuricemia by Akaike's information criteria.

CONCLUSION

Greater amounts of both visceral fat and liver fat were independently associated with hyperuricemia.

Role of Serum Uric Acid and Ferritin in the Development and Progression of NAFLD

Nonalcoholic fatty liver disease (NAFLD), tightly linked to the metabolic syndrome (MS), has emerged as a leading cause of chronic liver disease worldwide. Since it is potentially progressive towards non-alcoholic steatohepatitis (NASH) and hepatic fibrosis, up to cirrhosis and its associated complications, the need for predictive factors of NAFLD and of its advanced forms is mandatory. Despite the current "gold standard" for the assessment of liver damage in NAFLD being liver biopsy, in recent years, several non-invasive tools have been designed as alternatives to histology, of which fibroscan seems the most promising. Among the different serum markers considered, serum uric acid (SUA) and ferritin have emerged as possible predictors of severity of liver damage in NAFLD. In fact, as widely described in this review, they share common pathogenetic pathways and are both associated with hepatic steatosis and MS, thus suggesting a likely synergistic action. Nevertheless, the power of these serum markers seems to be too low if considered alone, suggesting that they should be included in a wider perspective together with other metabolic and biochemical parameters in order to predict liver damage.

Uric acid in metabolic syndrome: From an innocent bystander to a central player

Uric acid, once viewed as an inert metabolic end-product of purine metabolism, has been recently incriminated in a number of chronic disease states, including hypertension, metabolic syndrome, diabetes, non-alcoholic fatty liver disease, and chronic kidney disease. Several experimental and clinical studies support a role for uric acid as a contributory causal factor in these conditions. Here we discuss some of the major mechanisms linking uric acid to metabolic and cardiovascular diseases. At this time the key to understanding the importance of uric acid in these diseases will be the conduct of large clinical trials in which the effect of lowering uric acid on hard clinical outcomes is assessed. Elevated uric acid may turn out to be one of the more important remediable risk factors for metabolic and cardiovascular diseases.

High serum uric acid and risk of nonalcoholic fatty liver disease: A systematic review and meta-analysis

OBJECTIVES

Emerging evidence connects serum uric acid (SUA) levels to nonalcoholic fatty liver disease (NAFLD). The objective of this study was to systematically evaluate the association between SUA levels and risk of NAFLD by conducting a meta-analysis of available observational studies.

DESIGN AND METHODS

We searched for relevant studies in PubMed, Embase, China National Knowledge Infrastructure, and Wanfang databases until October 2014. All observational studies that evaluated SUA levels and NAFLD risks were included. Pooled adjusted odds ratio (OR) and corresponding 95% confidence intervals (CI) were calculated comparing the highest to lowest SUA category.

RESULTS

Four cross-sectional studies, two prospective studies, and three retrospective studies involving 55,573 participants were identified. In overall risk estimates, the pooled OR of NAFLD occurrence was 1.92 (95% CI: 1.59-2.31) comparing the highest to lowest SUA levels in a random effect model. Subgroup analysis showed that high SUA levels increased the risk of NAFLD in cross-sectional studies (OR: 2.18; 95% CI: 1.58-3.03), retrospective studies (OR 1.82; 95% CI: 1.43-2.33), and prospective studies (OR 1.43; 95% CI: 1.20-1.71). The risk of NAFLD seemed more pronounced among women (OR 1.85; 95% CI: 1.43-2.38) than among men (OR 1.56; 95% CI: 1.30-1.86).

CONCLUSION

This meta-analysis suggests that increased SUA level is associated with an exacerbated risk of NAFLD. This increased risk is probably independent of conventional NAFLD risk factors.

Epidemiological modifiers of non-alcoholic fatty liver disease: Focus on high-risk groups

An improved understanding of non-alcoholic fatty liver disease epidemiology would lead to identification of individuals at high risk of developing chronic liver disease and extra-hepatic complications, thus contributing to more effective case finding of non-alcoholic fatty liver disease among selected groups. We aimed to illustrate the epidemiology of non-alcoholic fatty liver disease in high-risk groups, which were identified based on existing literature. To this end, PubMed was searched to retrieve original articles published until May 2015 using relevant and pertinent keywords "nonalcoholic fatty liver disease" and "diabetes", "obesity", "hyperlipidaemia", "familial heterozygous hypobetalipoproteinaemia", "hypertension", "metabolic syndrome", "ethnicity", "family history" or "genetic polymorphisms". We found that age, sex and ethnicity are major physiological modifiers of the risk of non-alcoholic fatty liver disease, along with belonging to "non-alcoholic fatty liver disease families" and carrying risk alleles for selected genetic polymorphisms. Metabolic syndrome, diabetes, obesity, mixed hyperlipidaemia and hypocholesterolaemia due to familial hypobetalipoproteinaemia are the major metabolic modifiers of non-alcoholic fatty liver disease risk. Compared with these metabolic conditions, however, arterial hypertension appears to carry a relatively more modest risk of non-alcoholic fatty liver disease. A better understanding of the epidemiology of non-alcoholic fatty liver disease may result in a more liberal policy of case finding among high-risk groups.

The association between the serum levels of uric acid and alanine aminotransferase in a population-based cohort

BACKGROUND & AIMS

Elevated serum uric acid levels reflect and also cause both oxidative stress and insulin resistance and are frequently observed in patients with the metabolic syndrome. A strong association exists between the metabolic syndrome and non-alcoholic fatty liver disease (NAFLD). Therefore, we aimed to test the association between uric acid and elevated alanine aminotransferase (ALT), as a surrogate for NAFLD, using real-world data.

METHODS

Data used for the cross-sectional study were obtained from Maccabi Healthcare System, a 2-million member health maintenance organization in Israel. The population consisted of individuals aged 20-60 years who underwent blood tests for ALT and uric acid between 1997 and 2012. Individuals with secondary liver disease, celiac, and inflammatory bowel-disease were excluded. Subgroup analysis was performed in subjects who were given the diagnosis of fatty liver in their medical records (n = 2628).

RESULTS

The study population included 82,608 people (32.5% men, mean age 43.91 ± 10.15 years). There was a significant positive dose-response association between serum uric acid levels and the rate of elevated serum ALT (P for trend <0.001). In multivariable model, controlling for potential confounders, the association between uric acid and elevated ALT persisted (OR = 2.10, 95% CI 1.93-2.29, for the fourth quartile vs. the first). This association was maintained in all categories of gender and BMI. Similar results were observed among patients diagnosed with fatty liver (OR = 1.77, 1.22-2.57).

CONCLUSIONS

Serum uric acid is independently associated with elevated ALT, as a surrogate for NAFLD, and thus may serve as a serum marker for liver damage and should be further investigated as a risk factor for NAFLD.

Liver Fat Content Is Associated with Elevated Serum Uric Acid in the Chinese Middle-Aged and Elderly Populations: Shanghai Changfeng Study

Background and Aims

Although many studies have indicated a relationship between nonalcoholic fatty liver disease (NAFLD) and hyperuricemia, a few studies specifically examining the effects of the severity of liver fat content (LFC) on serum uric acid (SUA) and the presence of hyperuricemia because of the limitation of the examination methods for NAFLD. In this study, we investigate the relationship between the NAFLD and SUA levels in the Chinese population using standardized quantitative ultrasound.

Methods

A community-based study was conducted from May 2010 to December 2012. A total of 4,305 people aged 45 years and above without excessive drinking were enrolled. A standard interview and anthropometric and laboratory blood parameters were collected for each person. The standardized ultrasound hepatic/renal ratio and hepatic attenuation rate was used to quantify LFC.

Results

The prevalence of NAFLD and hyperuricemia was 33.1% and 17.1%, respectively. A total of 23.5% of the NAFLD subjects had hyperuricemia, and their SUA was higher than that of non-NAFLD subjects (327.2±76.8 vs 301.9±77.4 μmol/L, P<0.001). The LFC was positively correlated with SUA (r = 0.130, P<0.001) and an independent factor for SUA (standardized β = 0.054, P<0.001). The OR for the presence of hypreuricemia was 1.175 (95% CI 1.048–1.318; P<0.001) with a 1 SD increase in the log LFC. LFC greater than 10% was related to elevated SUA and an increased presence of hyperuricemia.

Conclusions

LFC accumulation was associated with an increase in the prevalence of hyperuricemia and elevated SUA in our community-based population. LFC greater than 10% is related to the risk for hyperuricemia.

Serum uric acid: a new therapeutic target for nonalcoholic fatty liver disease

INTRODUCTION

Nonalcoholic fatty liver disease (NAFLD) is a major, worldwide public health problem. NAFLD is recognized as a major cause of liver-related morbidity and mortality. However, physicians are currently limited by available treatment options. Recently, numerous studies have reported a correlation between serum uric acid (SUA) and NAFLD with numerous clinical and experimental studies demonstrating a significant correlation. This review will focus on the role of SUA in the development of NAFLD and its potential role as a new target for therapeutic intervention.

AREAS COVERED

This review discusses SUA as a significant independent factor in the development of NAFLD. Moreover, we introduce the causal relationship between SUA, metabolic syndrome, and NAFLD. We discuss two major theories of insulin resistance and inflammasomes as potential explanations of the mechanistic link between SUA and NAFLD. In addition, we review current and emerging therapeutic medications to control appropriate SUA levels.

EXPERT OPINION

There is an urgent need to develop novel, safe and effective therapies for the growing NAFLD epidemic. Reduction of SUA may be a promising potential treatment for patients with NAFLD. Clinical studies are required to determine the therapeutic effect of attenuation of hyperuricemia in humans with NAFLD.