Serum Uric Acid Levels and Nonalcoholic Fatty Liver Disease: A 2-Sample Bidirectional Mendelian Randomization Study

The association between visceral adipose accumulation and hyperuricemia risk among Chinese elder individuals: A nationwide prospective cohort study

Background

Lipid accumulation product (LAP), visceral adiposity index (VAI) and Chinese visceral adiposity index (CVAI) are proposed indices of visceral adipose accumulation. This study aimed to explore their relationship and temporal changes with hyperuricemia (HUA) development in a Chinese population.

Methods

A total of 4268 participants aged ≥45 years from the baseline survey of the China Health and Retirement Longitudinal Study were followed up for 4 years (from 2011 to 2015). The relationships among VAI, LAP, CVAI and HUA were analyzed using logistic regression. The predictive abilities of the VAI, LAP and CVAI for HUA were compared using receiver operating characteristic curves. Nonlinear relationships between the indices and HUA were analyzed using restricted cubic spline regression.

Results

During the four-year follow-up, 415 (9.72 %) patients experienced incident HUA . Elevated baseline VAI (odds ratio (OR): 1.19 (95 % confidence interval (95 %CI: 1.10, 1.29)), LAP (OR: 1.21 (95 % CI: 1.09, 1.34)) and CVAI (OR: 1.19 (95 % CI: 1.02, 1.40)) were significantly correlated with increased HUA risk (all P < 0.05). Compared to individuals with consistently low VAI,CVAIor LAP levels, those with elevated or consistently high levels of these indicators are more likely to have HUA. The area under curve (AUC) was slightly greater and more significant for the CVAI (AUC=0.641) than for the VAI (AUC=0.604) and LAP (AUC=0.628) (P < 0.05).

Conclusion

VAI, LAP and CVAI can predict HUA, with CVAI more efficient than VAI and LAP. Early management can lessen the burden of HUA in Chinese people aged 45 years or older with elevated CVAI levels.

Hyperuricemia and its related diseases: mechanisms and advances in therapy

Hyperuricemia, characterized by elevated levels of serum uric acid (SUA), is linked to a spectrum of commodities such as gout, cardiovascular diseases, renal disorders, metabolic syndrome, and diabetes, etc. Significantly impairing the quality of life for those affected, the prevalence of hyperuricemia is an upward trend globally, especially in most developed countries. UA possesses a multifaceted role, such as antioxidant, pro-oxidative, pro-inflammatory, nitric oxide modulating, anti-aging, and immune effects, which are significant in both physiological and pathological contexts. The equilibrium of circulating urate levels hinges on the interplay between production and excretion, a delicate balance orchestrated by urate transporter functions across various epithelial tissues and cell types. While existing research has identified hyperuricemia involvement in numerous biological processes and signaling pathways, the precise mechanisms connecting elevated UA levels to disease etiology remain to be fully elucidated. In addition, the influence of genetic susceptibilities and environmental determinants on hyperuricemia calls for a detailed and nuanced examination. This review compiles data from global epidemiological studies and clinical practices, exploring the physiological processes and the genetic foundations of urate transporters in depth. Furthermore, we uncover the complex mechanisms by which the UA induced inflammation influences metabolic processes in individuals with hyperuricemia and the association with its relative disease, offering a foundation for innovative therapeutic approaches and advanced pharmacological strategies.

Baseline and change in serum lipid and uric acid level over time and incident of nonalcoholic fatty liver disease (NAFLD) in Chinese adults

Observational studies have shown that non-alcoholic fatty liver disease (NAFLD) is strongly associated with metabolic dysfunction. However, there is a paucity of research on whether changes in indicators of serum metabolism contribute to the development of NAFLD. This study was conducted with 4084 participants who underwent healthy physical examinations at Jinling Hospital, Affiliated Hospital of Medical School, Nanjing University, Nanjing, China, in 2022 and 2023. Baseline and follow-up measurements, including anthropometric data, abdominal ultrasound and blood samples were collected. The diagnosis of NAFLD was based on the 2010 Chinese Guidelines on Diagnosis and Treatment of NAFLD. Multiple logistic regression was utilized to analyze the odds ratios (ORs) for the 1-year risk of NAFLD in connection with both baseline metabolic indicators and changes in metabolic indicators observed over the course of 1 year. A total of 3425 study participants who were free of NAFLD at baseline, including 1146 men and 2279 women, were included in the final analysis. The mean age was 34.43 ± 7.20 years. Participants who developed NAFLD were older, male and had higher levels of body mass index (BMI), blood pressure, fasting blood glucose (FBG), triglyceride (TG), total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), free triiodothyronine (fT3), uric acid (UA), alanine aminotransferase (ALT) and aspartate aminotransferase (AST); and lower levels of high-density lipoprotein cholesterol (HDL-C) and free thyroxine (fT4) (all P values < 0.05). The multivariable model showed that baseline BMI, diastolic blood pressure (DBP), TG, TC, HDL-C, LDL-C, UA, fT4, fT3, ALT and changes in TG, HDL-C, and UA were associated with the 1-year risk of developing NAFLD. The risk of NAFLD increased by 56% [OR 1.56, 95% Confidence Interval (CI) 1.32-1.87] and 40% (OR 1.40, 95% CI 1.19-1.64) for each standard deviation (SD) increase in altered TG values (1.01 mmol/L) and altered UA values (55 µmol/L) respectively. Conversely, for each SD (0.27 mmol/L) increase in HDL-C change, the 1-year risk of incident NAFLD was reduced by 50% (OR 0.50, 95% CI 0.40-0.62). The present study suggested that increases in TG and UA, and decreases in HDL-C, significantly increase the risk of developing NAFLD. Therefore, more attention should be paid to these factors in the management and prevention of NAFLD.

Correlation between serum uric acid to high-density lipoprotein cholesterol ratio and atrial fibrillation in patients with NAFLD

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is independently associated with atrial fibrillation (AF) risk. The uric acid (UA) to high-density lipoprotein cholesterol (HDL-C) ratio (UHR) has been shown to be closely associated with cardiovascular disease (CVD) and NAFLD. The aim of this study is to clarify whether elevated UHR is associated with the occurrence of AF in patients with NAFLD and to determine whether UHR predicted AF.

METHODS

Patients diagnosed with NAFLD in the Department of Cardiovascular Medicine of the Second Hospital of Shanxi Medical University from January 1, 2020, to December 31, 2021, were retrospectively enrolled in this study. The study subjects were categorized into AF group and non-AF group based on the presence or absence of combined AF. Logistic regression was performed to evaluate the correlation between UHR and AF. Sensitivity analysis and subgroup interaction analysis were performed to verify the robustness of the study results. Receiver operating characteristic (ROC) curve analysis was used to determine the optimal cutoff value for UHR to predict the development of AF in patients with NAFLD.

RESULTS

A total of 421 patients with NAFLD were included, including 171 in the AF group and 250 in the non-AF group. In the univariate regression analysis, NAFLD patients with higher UHR were more likely to experience AF, and the risk of AF persisted after confounding factors were adjusted for (OR: 1.010, 95%CI: 1.007-1.013, P<0.001). AF risk increased with increasing UHR quartile (P for trend < 0.001). Despite normal serum UA and HDL-C, UHR was still connected with AF in patients with NAFLD. All subgroup variables did not interact significantly with UHR in the subgroup analysis. The ROC curve analysis showed that the areas under the curve for UA, HDL-C, and UHR were 0.702, 0.606, and 0.720, respectively, suggesting that UHR has a higher predictive value for AF occurrence in NAFLD patients compared to HDL-C or UA alone.

CONCLUSION

Increased UHR level was independently correlated with a high risk of AF in NAFLD patients.

Amyotrophic lateral sclerosis and osteoporosis: a two-sample Mendelian randomization study

Background

A few observational studies revealed that amyotrophic lateral sclerosis (ALS) was tightly connected with osteoporosis. However, the results of previous studies were inconsistent, and the causal effect of ALS on osteoporosis has not been investigated. To do so, the two-sample Mendelian randomization (MR) method was employed to estimate the causality.

Methods

The instrumental variables (IVs) for ALS were selected from one GWAS summary dataset (27,205 ALS cases and 110,881 controls), and bone mineral density (BMD) in the femoral neck (FN), lumbar spine (LS), and forearm, extracted from another large-scale GWAS summary database (53,236 cases), were used as phenotypes for osteoporosis. Random-effects inverse variance weighted (IVW), MR Egger, weighted median, simple mode, and weighted mode were conducted to evaluate the causality. Sensitivity analyses were further performed to explore heterogeneity and pleiotropy.

Results

A total of 10 qualified SNPs were finally selected as proxies for ALS. The results of random effects from IVW revealed that ALS has no causal effect on FN-BMD (beta: -0.038, 95% CI: -0.090 to 0.015, SE: 0.027, p = 0.158), LS-BMD (beta: -0.015, 95% CI: -0.076 to 0.046, SE: 0.031, p = 0.629), and forearm BMD (beta: 0.044, 95% CI: -0.063 to 0.152, SE: 0.055, p = 0.418). These results were confirmed using the MR-Egger, weighted median, simple model, and weighted model. No heterogeneity or pleiotropy was detected (p > 0.05 for all).

Conclusion

Contrary to previous observational studies, our study figured out that no causal effect existed between ALS and osteoporosis. The disparity in results is probably attributed to secondary effects such as physical inactivity and muscle atrophy caused by ALS.

Serum uric acid is related to liver and kidney disease and 12-year mortality risk after myocardial infarction

Objective

To study the associations of non-alcoholic fatty liver disease (NAFLD), chronic kidney disease (CKD), and serum uric acid (SUA) in patients with post-myocardial infarction (MI) patients, and the relationship of SUA with 12-year mortality risk.

Methods

We included 3,396 patients (60-80 years old, 78% men) of the Alpha Omega Cohort. Multivariable prevalence ratios (PRs) were obtained for the association of NAFLD [fatty liver index (FLI), ≥77 (women) and ≥79 (men)] with CKD [estimated glomerular filtration rate (eGFR), <60 mL/min per 1.73 m2]. We calculated sensitivity and specificity of SUA to detect the (combined) presence and absence of NAFLD and CKD. Cause-specific mortality was monitored from enrolment (2002-2006) through December 2018. Hazard ratios (HRs) for all-cause and cardiovascular disease (CVD) mortality in SUA categories were obtained from multivariable Cox models.

Results

Median baseline FLI was 67 (men, 68; women, 64), and mean ± SD eGFR was 81 ± 20 mL/min per 1.73 m2 (17% with CKD). Sex-specific FLI was associated with higher CKD prevalence (PRtertile3 vs. tertile1, 1.94; 95% confidence interval: 1.57, 2.39). Baseline SUA was 0.36 ± 0.09 mmol/L. With increasing SUA concentrations, specificity for the presence of NAFLD, CKD, or both increased, and sensitivity decreased. During 12 (interquartile range, 9-14) years of follow-up, 1,592 patients died (713 from CVD). HRs ranged from 1.08 (0.88, 1.32) for SUA ≤0.25 mmol/L to 2.13 (1.75, 2.60) for SUA >0.50 mmol/L vs. SUA >0.30-0.35 mmol/L for all-cause mortality. For CVD mortality, HRs ranged from 1.05 (0.77, 1.44) to 2.43 (1.83, 3.25).

Conclusions

NAFLD and CKD were strongly associated, which was reflected by higher SUA concentrations. SUA was a strong predictor of 12-year mortality risk after MI.

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.

Assessing the causal relationships between human blood metabolites and the risk of NAFLD: A comprehensive mendelian randomization study

Background: Non-alcoholic fatty liver disease (NAFLD) is a liver disease associated with obesity, insulin resistance, type 2 diabetes mellitus (T2DM), and metabolic syndrome. The risk factors for NAFLD have not been identified. Metabolic dysfunction has been found to be an important factor in the pathogenesis and progression of NAFLD. However, the causal impact of blood metabolites on NAFLD is unclear.

Methods: We performed a two-sample Mendelian randomization (MR) study. A genome-wide association study (GWAS) with 7824 participants provided data on 486 human blood metabolites. Outcome information was obtained from a large-scale GWAS meta-analysis of NAFLD, which contained 8,434 cases and 770,180 controls of Europeans. The inverse variance weighted (IVW) model was chosen as the primary two-sample MR analysis approach, followed by sensitivity analyses such as the heterogeneity test, horizontal pleiotropy test, and leave-one-out analysis. In addition, we performed replication, meta-analysis, and metabolic pathway analysis. We further conducted colocalization analysis to deeply reflect the causality.

Results: After rigorous genetic variant selection, IVW, sensitivity analysis, replication, and meta-analysis, two known metabolites were identified as being associated with the development of NAFLD [biliverdin: OR = 1.45; 95% CI 1.20-1.75; p = 0.0001; myristoleate: OR = 0.57; 95% CI 0.39-0.83; p = 0.0030].

Conclusion: By combining genomics with metabolomics, our findings provide a new perspective on the underlying mechanisms of NAFLD and have important implications for the screening and prevention of NAFLD.

Triglyceride-Glucose Index is Significantly Associated with the Risk of Hyperuricemia in Patients with Nonalcoholic Fatty Liver Disease

Purpose

The triglyceride-glucose (TyG) index is a new index of insulin resistance (IR), and its association with hyperuricemia (HUA) is unclear. The aim of this study was to investigate whether TyG is an independent risk factor for hyperuricemia (HUA) in patients with nonalcoholic fatty liver disease (NAFLD).

Patients and Methods

We retrospectively analyzed 461 patients with ultrasound-confirmed NAFLD and calculated the TyG index. Multivariate logistic regression was used to analyze the relationship between the TyG index and HUA in NAFLD patients. The correlation between the TyG index and HUA was further confirmed by a restricted cubic spline. Furthermore, the stability of the association between TyG index and HUA was examined using subgroup analysis. Receiver operating characteristic (ROC) curves were constructed to evaluate the predictive value of the TyG index on HUA. Multivariate linear regression was used to analyze the linear relationship between the TyG index and serum uric acid.

Results

A total of 166 HUA patients and 295 non-HUA patients were included in the study. The results of multivariate logistic regression analysis showed that after controlling the confounding risk factors, TyG was still an independent risk factor for HUA (OR = 2.00, 95% CI: 1.38 -2.91, p < 0.001). Restricted cubic splines showed that HUA risk increased linearly with TyG across the entire TyG range. The ROC curve showed that TyG index was better than triglyceride in predicting HUA in NAFLD patients, with AUC values of 0.62 and 0.59, respectively. Multiple linear regression analysis showed that TyG index was significantly positively correlated with blood uric acid (B = 1.37, 95% CI: 0.67-2.08, p < 0.001).

Conclusion

TyG index is an independent risk factor for HUA in patients with NAFLD. The increase of the TyG index level is closely related to the occurrence and development of HUA in patients with NAFLD.

Serum uric acid to creatinine ratio is associated with higher prevalence of NAFLD detected by FibroScan in the United States

Background

The association between the serum uric acid (sUA) to creatinine ratio (sUA/Cr) and non‐alcoholic fatty liver disease (NAFLD) has not been sufficiently clarified. In this study, we investigated the relationship between sUA/Cr and NAFLD among participants in the United States.

Methods

We performed a cross‐sectional study based on data from the National Health and Nutrition examination Survey (NHANES) 2017–2018. A measured controlled attenuation parameter (CAP) value of ≥274 dB/m detected by Fibroscan was used to identify hepatic steatosis. SUA/Cr was calculated as sUA divided by serum creatinine. Multivariate logistic regression analysis was used to estimate the association between sUA/Cr and NAFLD. The adjusted odds ratio (OR) of sUA/Cr for NAFLD was estimated, and subgroup analysis stratified by sex was also conducted. The nonlinear relationship between sUA/Cr and NAFLD was further described using smooth curve fittings and threshold‐effect analysis.

Results

We found that sUA/Cr was positively correlated with NAFLD status after fully adjustment for confounding factors. In subgroup analysis stratified by sex, the positive interaction between sUA/Cr and NAFLD status only existed in women but not in men. Moreover, the nonlinear association between sUA/Cr and NAFLD status was an inverted U‐shaped curve with an inflection point at 9.7 among men.

Conclusions

Our study identified that sUA/Cr was positively associated with the risk of NAFLD among individuals in the United States. Moreover, the correlation between sUA/Cr and NAFLD differed according to sex.