Sex Difference in the Association between Serum Homocysteine Level and Non-Alcoholic Fatty Liver Disease

Homocysteine, folate, and nonalcoholic fatty liver disease: a systematic review with meta-analysis and Mendelian randomization investigation

BACKGROUND

Circulating concentrations of homocysteine and folate are inconsistently associated with the risk of nonalcoholic fatty liver disease (NAFLD) in observational studies.

OBJECTIVES

We conducted a meta-analysis and Mendelian randomization (MR) analyses to examine these associations.

METHODS

We performed a meta-analysis of observational studies identified from 3 databases to evaluate the associations of serum homocysteine and folate concentrations with NAFLD from inception to 7 April 2022. We conducted MR analyses to strengthen the causal inference in these associations. Independent single-nucleotide polymorphisms without linkage disequilibrium (r2 < 0.01) that were strongly associated (P < 5 × 10-8) with serum homocysteine (n = 13) and folate (n = 2) concentrations were selected as instrumental variables from 2 meta-analyses of genome-wide association studies (GWASs) of 44,147 and 37,645 individuals of European ancestry, respectively. Data on NAFLD were obtained from a GWAS of 8434 NAFLD cases and 770,180 controls of European ancestry. We further included 4 liver enzymes as secondary outcomes from a GWAS of 361,194 individuals with European descent.

RESULTS

Twenty-two observational studies comprising 30,368 participants were included in the meta-analysis. There was a positive association between serum homocysteine and NAFLD risk (n = 20; OR: 1.96; 95% CI: 1.57, 2.45) and an inverse association between serum folate and NAFLD risk (n = 12; OR: 0.75; 95% CI: 0.58, 0.99). In MR analysis, the ORs of NAFLD were 1.17 (95% CI: 1.01, 1.36) and 0.75 (95% CI: 0.55, 1.02) per 1-SD increment of genetically predicted circulating concentrations of homocysteine and folate, respectively. Each 1-SD increase of genetically predicted circulating homocysteine and folate conferred a change in ALT concentrations of 0.62 U/L (95% CI: 0.20, 1.04) and -0.84 U/L (95% CI: -0.14, -1.54).

CONCLUSIONS

This study suggests a potential role of circulating homocysteine and possibly folate in NAFLD, which calls for future clinical exploration of the possibility of lowering homocysteine concentrations to prevent NAFLD. This systematic review was registered at PROSPERO as CRD42021296434.

Characterization of Early-Stage Alcoholic Liver Disease with Hyperhomocysteinemia and Gut Dysfunction and Associated Immune Response in Alcohol Use Disorder Patients

Heavy alcohol consumption can cause hyperhomocysteinemia, which could be consequential in the proinflammatory response and worsening of the neurobehavioral domains of alcohol use disorder (AUD), such as alcohol withdrawal. We examined the role of heavy drinking, hyperhomocysteinemia, gut dysfunction and inflammation in early-stage alcoholic liver disease (ALD) in AUD patients. A total of 110 AUD patients without clinical manifestations of liver injury were grouped by the serum homocysteine levels (SHL): normal ≤ 13 µmol/L (Group 1 (Gr.1); n = 80), and elevated > 13 µmol/L (Group 2 (Gr.2), n = 30). A comprehensive metabolic panel, SHL, a nutritional assessment, and drinking history assessed by the timeline followback questionnaire were evaluated. A subset analysis was performed on 47 subjects (Gr.1 n = 27; Gr.2 n = 20) for additional measures: Clinical Institute Withdrawal Assessment for Alcohol (CIWA) score, plasma cytokines (interleukin-1β (IL-1β)), gut dysfunction markers (lipopolysaccharide (LPS), and LPS-binding protein (LBP)); 27% of the AUD patients exhibited hyperhomocysteinemia. SHL was significantly associated (p = 0.034) with heavy drinking days (HDD90). Subset analyses showed that the withdrawal ratings were both clinically and statistically (p = 0.033) elevated and significantly associated with hyperhomocysteinemia (p = 0.016) in Gr.2. LBP, IL1-β, SHL, and HDD90 showed significant cumulative effects (adjusted R² = 0.627) on withdrawal ratings in Gr.2 subset. Alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were significantly higher in all Gr.2 patients; AUROC showed a fair level of true positivity for ALT (0.676), and AST (0.686). Il1-β, LBP, SHL, and HDD90 showed significant cumulative effects (adjusted R² = 0.554) on the elevated ALT in Gr.2 subset as well. The gut-brain derived proinflammatory response, patterns of heavy drinking, and hyperhomocysteinemia were closely associated with clinically elevated alcohol withdrawal and elevated liver injury. Hyperhomocysteinemia could have a potential phenotypic marker response indicative of early-stage ALD along with AUD.

Genetic Association of Plasma Homocysteine Levels with Gastric Cancer Risk: A Two-Sample Mendelian Randomization Study

BACKGROUND

The association of plasma homocysteine level (PHL) with gastric cancer risk was reported in observational studies. However, the causality is challenging due to confounding factors and the lack of evidence from well-designed cohort studies. Herein, we performed a two-sample Mendelian randomization (MR) analysis to investigate whether PHL is causally related to gastric cancer risk.

METHODS

We performed the MR analysis based on the results from genome-wide association studies consisting of 2,631 patients with gastric cancer and 4,373 controls. An externally weighted genetic risk score (wGRS) was constructed with 15 SNPs with well-established associations with PHL. We utilized logistic regression model to estimate associations of PHL-related SNPs and wGRS with gastric cancer risk in total population and in strata by sex, age, and study site, in addition to a series of sensitivity analyses.

RESULTS

High genetically predicted PHL was associated with an increased gastric cancer risk (per SD increase in the wGRS: OR = 1.07; 95% confidence interval, 1.01-1.12; P = 0.011), which was consistent in sensitivity analyses. Subgroup analyses provided evidence of a stronger association with gastric cancer risk in women than in men. MR-Egger and weighted median regression suggested that potentially unknown pleiotropic effects were not biasing the association between PHL and gastric cancer risk.

CONCLUSIONS

These results revealed that genetically predicted high PHL was associated with an increased gastric cancer risk, suggesting that high PHL may have a causal role in the etiology of gastric cancer.

IMPACT

These findings provide causal inference for PHL on gastric cancer risk, suggesting a causal role of high PHL in the etiology of gastric cancer.

Sex differences in risk factors for stroke in patients with hypertension and hyperhomocysteinemia

Data on the sex-specific differences in risk of stroke among patients with H-type hypertension are limited. We aimed to analyze interactions between sex and other risk factors on stroke, including the sex-methylenetetrahydrofolate reductase (MTHFR) interaction. A retrospective analysis of baseline data from 2040 patients with hypertension and hyperhomocysteinemia (HHcy) included demographic characteristics, biomarkers, history of chronic diseases and lifestyle factors. Polymerase chain reaction-restriction fragment length polymorphism method was used to investigate the C677T polymorphism of MTHFR gene. We examined independent effects and interactions between sex and stratified factors on the risk of stroke by logistic regression model. A total of 1412 patients suffered stroke, and the prevalence of stroke was 70.65% in men and 66.53% in women. Both men and women had independent risk factors for stroke, including diabetes mellitus, atrial fibrillation, smoking, increased level of systolic blood pressure (SBP) and plasma total homocysteine (tHcy), as well as the decreased level of high-density lipoprotein cholesterol. Diastolic blood pressure (DBP) -specific risk of stroke was unique to men. Interactions between sex and other risk factors on stroke risk were statistically significant: age, fasting plasma glucose (FPG), SBP, DBP, triglycerides (TG) and tHcy. Furthermore, tHcy interacted with age, SBP and DBP in men, and age, SBP, DBP, FPG, and TG in women to modulate the risk of stroke. Although TT genotype did not have an independent effect on stroke, it could interact with sex and FPG, TG and SBP to increase stroke. In conclusion, sex-specific differences are useful to stratify the risk of stroke and assist clinicians in the decision to select a reasonable therapeutic option for high-risk patients.

The prevalence and risk factors of young male schizophrenics with non-alcoholic fatty liver disease

OBJECTIVE

In this study, we compared the prevalence rate of non-alcoholic fatty liver disease (NAFLD) between young males with schizophrenia and the general young males as the control group, and we also investigated the risk factors of NAFLD in young males with schizophrenia.

MATERIALS AND METHODS

This is a large cross-sectional study consisting of the study group and parallel control group. The study group comprises 202 cases of young males with schizophrenia recruited from Liaoning province Demobilized Soldiers Kangning Hospital, and 149 healthy young males were recruited as the control group. The clinical evaluation included Positive and Negative Syndrome Scale (PANSS), basic information, disease-related information, and physical examination information. The laboratory tests included fasting blood glucose, total cholesterol, triglyceride, alanine aminotransferase (ALT), and aspartate aminotransferase (AST). The physical examination included liver ultrasonography.

RESULTS

No statistical difference was observed between the study and control groups regarding age (30.5±3.9 vs 30.7±3.6), body mass index (BMI), blood pressure, fasting glucose level, and total cholesterol. NAFLD was observed in both the study and control groups. The prevalence of NAFLD was 49.5% (100/202) in the study group, and 20.1% (30/149) in the control group. The study group was further divided into NAFLD group and non-NAFLD group. There were significant differences in medication combination, drug dosage, negative factor score in PANSS (14.1±4.0 vs 12.7±4.5), BMI, fasting glucose level, total cholesterol, triglyceride, ALT, and AST between NAFLD group and non-NAFLD group. According to the results of the multiple-factor analysis, the onset of NAFLD among young males with schizophrenia was significantly correlated with the following factors: triglyceride, BMI, medication combination, drug dosage, and negative factor score in PANSS.

CONCLUSION

The prevalence of NAFLD in the study group was significantly higher than that in the control group. Multivariate analysis indicated that, triglyceride, BMI, medication combination, drug dosage, and negative factor score in PANSS were significantly related to NAFLD in patients with schizophrenia.

Association between homocysteine and non-alcoholic fatty liver disease in Chinese adults: a cross-sectional study

Background

Non-alcoholic fatty liver disease (NAFLD) is the most common liver disease worldwide, and its prevalence is likely to rise even further. To help understand the pathogenesis and early prevention of progressive NAFLD, this large-scale study was designed to explore the potential association between homocysteine and the prevalence of NAFLD.

Methods

A total of 7203 subjects aged 18 years or older were enrolled in this cross-sectional study. The association of homocysteine with the prevalence of NAFLD, in the total sample and stratified by subgroups, was examined using multiple logistic regression analyses.

Results

Subjects in the higher quartiles of homocysteine had a higher prevalence of NAFLD. After multivariate adjustment, the odds ratio (OR) for NAFLD in the highest compared with the lowest quartile of homocysteine was 2.08 (95% confidence interval [CI] 1.61, 2.67). Moreover, in the subgroup analyses, we found an effect modification by gender, body mass index (BMI) and smoking status on the association between homocysteine and the prevalence of NAFLD (P for interaction: 0.001, 0.002 and <0.001, respectively). A stronger association was observed in female, obese and non-smoking adults than in male, normal weight and smoking subjects.

Conclusion

Homocysteine was significantly associated with the prevalence of NAFLD, particularly in female, obese or non-smoking adults.