Risk Factors of Depression Screened by Two-Sample Mendelian Randomization Analysis:A Systematic Review

Objective This study explored the potentially modifiable factors for depression and major depressive disorder(MDD)from the MR-Base database and further evaluated the associations between drug targets with MDD.Methods We analyzed two-sample of Mendelian randomization(2SMR)using genetic variant depression(n=113,154)and MDD(n=208,811)from Genome-Wide Association Studies(GWAS).Separate calculations were performed with modifiable risk factors from MR-Base for 1,001 genomes.The MR analysis was performed by screening drug targets with MDD in the DrugBank database to explore the therapeutic targets for MDD.Inverse variance weighted(IVW),fixed-effect inverse variance weighted(FE-IVW),MR-Egger,weighted median,and weighted mode were used for complementary calculation.Results The potential causal relationship between modifiable risk factors and depression contained 459 results for depression and 424 for MDD.Also,the associations between drug targets and MDD showed that SLC6A4,GRIN2A,GRIN2C,SCN10A,and IL1B expression are associated with an increased risk of depression.In contrast,ADRB1,CHRNA3,HTR3A,GSTP1,and GABRG2 genes are candidate protective factors against depression.Conclusion This study identified the risk factors causally associated with depression and MDD,and estimated 10 drug targets with significant impact on MDD,providing essential information for formulating strategies to prevent and treat depression.

Causal association between 25-hydroxyvitamin D status and cataract development:A two-sample Mendelian randomization study

BACKGROUND Vitamin deficiencies are linked to various eye diseases,and the influence of vitamin D on cataract formation has been noted in prior research.However,detailed investigations into the causal relationship between 25-(OH)D status and cataract development remain scarce.AIM To explore a possible causal link between cataracts and vitamin D.METHODS In this study,we explored the causal link between 25-(OH)D levels and cataract development using Mendelian randomization.Our analytical approach included inverse-variance weighting(IVW),MR-Egger,weighted median,simple mode,and weighted mode methods.The primary analyses utilized IVW with random effects,supplemented by sensitivity and heterogeneity tests using both IVW and MR-Egger.MR-Egger was also applied for pleiotropy testing.Additionally,a leave-one-out analysis helped identify potentially impactful single-nucleotide polymorphisms.RESULTS The analysis revealed a positive association between 25-(OH)D levels and the risk of developing cataracts(OR=1.11,95%CI:1.00-1.22;P=0.032).The heterogeneity test revealed that our IVW analysis exhibited minimal heterogeneity(P>0.05),and the pleiotropy test findings confirmed the absence of pleiotropy within our IVW analysis(P>0.05).Furthermore,a search of the human genotype-phenotype association database failed to identify any potentially relevant risk-factor single nucleotide polymorphisms.CONCLUSION There is a potential causal link between 25-(OH)D levels and the development of cataracts,suggesting that greater 25-(OH)D levels may be a contributing risk factor for cataract formation.Further experimental research is required to confirm these findings.

Association between inflammatory bowel disease and all-cause dementia:A two-sample Mendelian randomization study

BACKGROUND Numerous observational studies have documented a correlation between inflammatory bowel disease(IBD)and an increased risk of dementia.However,the causality of their associations remains elusive.AIM To assess the causal relationship between IBD and the occurrence of all-cause dementia using the two-sample Mendelian randomization(MR)method.METHODS Genetic variants extracted from the large genome-wide association study(GWAS)for IBD(the International IBD Genetics Consortium,n=34652)were used to identify the causal link between IBD and dementia(FinnGen,n=306102).The results of the study were validated via another IBD GWAS(United Kingdom Biobank,n=463372).Moreover,MR egger intercept,MR pleiotropy residual sum and outlier,and Cochran's Q test were employed to evaluate pleiotropy and heterogeneity.Finally,multiple MR methods were performed to estimate the effects of genetically predicted IBD on dementia,with the inverse variance weighted approach adopted as the primary analysis.RESULTS The results of the pleiotropy and heterogeneity tests revealed an absence of significant pleiotropic effects or heterogeneity across all genetic variants in outcome GWAS.No evidence of a causal effect between IBD and the risk of dementia was identified in the inverse variance weighted[odds ratio(OR)=0.980,95%CI:0.942-1.020,P value=0.325],weighted median(OR=0.964,95%CI:0.914-1.017,P value=0.180),and MR-Egger(OR=0.963,95%CI:0.867-1.070,P value=0.492)approaches.Consistent results were observed in validation analyses.Reverse MR analysis also showed no effect of dementia on the development of IBD.Furthermore,MR analysis suggested that IBD and its subtypes did not causally affect allcause dementia and its four subtypes,including dementia in Alzheimer's disease,vascular dementia,dementia in other diseases classified elsewhere,and unspecified dementia.CONCLUSION Taken together,our MR study signaled that IBD and its subentities were not genetically associated with all-cause dementia or its subtypes.Further large prospective studies are warranted to elucidate the impact of intestinal inflammation on the development of dementia.

Lack of a causal relationship between tea intake and sleep disorders: a two-sample Mendelian randomization study

Background:The relationship between tea intake(TI)and sleep disorders(SDs)has been a topic of interest for some time,but there remains a lack of data showing a causal relationship.We aimed to use a two-sample Mendelian randomization study to determine whether there is a causal link between TI and SDs.Methods:We collected data regarding TI,with a focus on green tea intake(GTI),herbal tea intake(HTI),and rooibos tea intake(RTI);and data regarding SDs and insomnia from genome-wide association studies.We analyzed these data using an inverse variance-weighted two-sample Mendelian randomization study,by means of the TwoSampleMR package in R4.2.3 software.Results:We found no genetic causal relationships of TI,GTI,HTI,or RTI with insomnia.The odds ratios(ORs)for these relationships were as follows:TI:OR=0.61,95%confidence interval(CI):0.29–1.28;GTI:OR=1.04,95%CI:0.95–1.14;HTI:OR=0.98,95%CI:0.82–1.17;and RTI:OR=1.04,95%CI:0.99–1.09.In addition,there were no genetic causal relationships of TI,GTI,HTI,or RTI with SDs.The OR values for these relationships were as follows:TI:OR=0.6,95%CI:0.34–1.06;GTI:OR=1,95%CI:0.93–1.07;HTI:OR=0.89,95%CI:0.66–1.2;and RTI:OR=1.02,95%CI:0.98–1.06.Conclusion:We found no causal relationships of TI with SDs or insomnia,irrespective of the type of tea consumed.However,additional Mendelian randomization studies are required to further explore the relationships of the timing and quantity of tea consumption with SDs and insomnia.

Genetic causal relationship between tea intake and cerebral aneurysm: a two-sample Mendelian Randomization Study

Background:Prior research has established a strong link between cerebral aneurysm(CA)occurrence and inflammation.Tea intake(TI)has been found to have anti-inflammatory properties through multiple mechanisms,potentially lowering CA incidence.This study aims to employ Mendelian Randomization(MR)methodology to explore the genetic causality between TI and CA.Methods:We collected Genome-wide association study(GWAS)data for CA,TI,Green tea intake(GTI),Herbal tea intake(HTI),and Rooibos tea intake(RTI).The MR analysis employed the TwoSampleMR package and utilized the inverse variance-weighted(IVW)method.Results:The findings suggest no genetic causal relationship between TI and CA(IVW:OR=1.10,95%CI:0.59–2.05,P=0.772).Similarly,there is no genetic causal association between GTI and CA(IVW:OR=1.07,95%CI:0.91–1.26,P=0.388),HTI and CA(IVW:OR=1.00,95%CI:0.89–1.13,P=0.943),or RTI and CA(IVW:OR=1.02,95%CI:0.96–1.09,P=0.472).Conclusion:There is no genetic causal relationship between TI and CA,and the different types of tea do not change this result.Further MR analysis is needed to investigate whether there is a potential genetic causal association between the quantity of TI and CA.

No genetic causal relationship between tea intake and diabetes:a two-sample Mendelian randomization study

Background:Previous studies have suggested a potential risk-reducing effect of tea intake(TI)on diabetes.However,the specific impacts of TI on different types of diabetes and its underlying mechanisms remain unclear.To further explore this topic,we conducted a comprehensive investigation to assess the causal relationship between TI and various types of diabetes,as well as its effects on blood glucose(Glu)and glycated hemoglobin(HbA1).Methods:We collected genome-wide association study data for TI,diabetes,type 1 diabetes(T1D),type 2 diabetes(T2D),Glu,HbA1,green tea intake,herbal tea intake,and Rooibos tea intake from the IEU database.Subsequently,we performed two-sample Mendelian randomization analysis using the TwoSampleMR package.Results:Our analysis revealed no evidence of a causal relationship between TI and the incidence of diabetes,T1D,blood Glu,HbA1c,or T2D.Similarly,no genetic causal relationship was found between green tea intake and diabetes,T1D,T2D,Glu,or HbA1c.The same applied to herbal tea intake and Rooibos tea intake,as there was no genetic causal link with diabetes,T1D,T2D,Glu,or HbA1c.Conclusion:Based on our findings,there is no indication of a causal relationship between TI and the incidence of all types of diabetes,regardless of the specific tea type.However,to comprehensively understand the potential effects of TI on diabetes incidence,including the quantity and timing of intake,further evaluation through additional Mendelian randomization studies is warranted.

Functional investigation and two-sample Mendelian randomization study of primary biliary cholangitis hub genes

BACKGROUND The identification of specific gene expression patterns is crucial for understanding the mechanisms underlying primary biliary cholangitis(PBC)and finding relevant biomarkers for diagnosis and therapeutic evaluation.AIM To determine PBC-associated hub genes and assess their clinical utility for disease prediction.METHODS PBC expression data were obtained from the Gene Expression Omnibus database.Overlapping genes from differential expression analysis and weighted gene coexpression network analysis(WGCNA)were identified as key genes for PBC.Kyoto Encyclopedia of Genes and Genomes and Gene Ontology analyses were performed to explore the potential roles of key genes.Hub genes were identified in protein-protein interaction(PPI)networks using the Degree algorithm in Cytoscape software.The relationship between hub genes and immune cells was investigated.Finally,a Mendelian randomization study was conducted to determine the causal effects of hub genes on PBC.RESULTS We identified 71 overlapping key genes using differential expression analysis and WGCNA.These genes were primarily enriched in pathways related to cytokinecytokine receptor interaction,and Th1,Th2,and Th17 cell differentiation.We utilized Cytoscape software and identified five hub genes(CD247,IL10,CCL5,CCL3,and STAT3)in PPI networks.These hub genes showed a strong correlation with immune cell infiltration in PBC.However,inverse variance weighting analysis did not indicate the causal effects of hub genes on PBC risk.CONCLUSION Hub genes can potentially serve as valuable biomarkers for PBC prediction and treatment,thereby offering significant clinical utility.

Causal associations between gastroesophageal reflux disease and essential hypertension: A bidirectional Mendelian randomization study

BACKGROUND Clinical studies have reported that patients with gastroesophageal reflux disease(GERD)have a higher prevalence of hypertension.AIM To performed a bidirectional Mendelian randomization(MR)analysis to investi-gate the causal link between GERD and essential hypertension.METHODS Eligible single nucleotide polymorphisms(SNPs)were selected,and weighted median,inverse variance weighted(IVW)as well as MR egger(MR-Egger)re-gression were used to examine the potential causal association between GERD and hypertension.The MR-Pleiotropy RESidual Sum and Outlier analysis was used to detect and attempt to reduce horizontal pleiotropy by removing outliers SNPs.The MR-Egger intercept test,Cochran’s Q test and“leave-one-out”sen-sitivity analysis were performed to evaluate the horizontal pleiotropy,heterogen-eities,and stability of single instrumental variable.RESULTS IVW analysis exhibited an increased risk of hypertension(OR=1.46,95%CI:1.33-1.59,P=2.14E-16)in GERD patients.And the same result was obtained in replication practice(OR=1.002,95%CI:1.0008-1.003,P=0.000498).Meanwhile,the IVW analysis showed an increased risk of systolic blood pressure(β=0.78,95%CI:0.11-1.44,P=0.021)and hypertensive heart disease(OR=1.68,95%CI:1.36-2.08,P=0.0000016)in GERD patients.Moreover,we found an decreased risk of Barrett's esophagus(OR=0.91,95%CI:0.83-0.99,P=0.043)in essential hypertension patients.CONCLUSION We found that GERD would increase the risk of essential hypertension,which provided a novel prevent and therapeutic perspectives of essential hypertension.

Genetically predicted fatty liver disease and risk of psychiatric disorders: A mendelian randomization study

BACKGROUND Non-alcoholic fatty liver disease(NAFLD)and alcohol-related liver disease(Ar-LD)constitute the primary forms of chronic liver disease,and their incidence is progressively increasing with changes in lifestyle habits.Earlier studies have do-cumented a correlation between the occurrence and development of prevalent mental disorders and fatty liver.AIM To investigate the correlation between fatty liver and mental disorders,thus ne-cessitating the implementation of a mendelian randomization(MR)study to elu-cidate this association.METHODS Data on NAFLD and ArLD were retrieved from the genome-wide association studies catalog,while information on mental disorders,including Alzheimer's disease,schizophrenia,anxiety disorder,attention deficit hyperactivity disorder(ADHD),bipolar disorder,major depressive disorder,multiple personality dis-order,obsessive-compulsive disorder(OCD),post-traumatic stress disorder(PTSD),and schizophrenia was acquired from the psychiatric genomics consor-tium.A two-sample MR method was applied to investigate mediators in signifi-cant associations.RESULTS After excluding weak instrumental variables,a causal relationship was identified between fatty liver disease and the occurrence and development of some psychia-tric disorders.Specifically,the findings indicated that ArLD was associated with a significantly elevated risk of developing ADHD(OR:5.81,95%CI:5.59-6.03,P<0.01),bipolar disorder(OR:5.73,95%CI:5.42-6.05,P=0.03),OCD(OR:6.42,95%CI:5.60-7.36,P<0.01),and PTSD(OR:5.66,95%CI:5.33-6.01,P<0.01).Meanwhile,NAFLD significantly increased the risk of developing bipolar disorder(OR:55.08,95%CI:3.59-845.51,P<0.01),OCD(OR:61.50,95%CI:6.69-565.45,P<0.01),and PTSD(OR:52.09,95%CI:4.24-639.32,P<0.01).CONCLUSION Associations were found between genetic predisposition to fatty liver disease and an increased risk of a broad range of psychiatric disorders,namely bipolar disorder,OCD,and PTSD,highlighting the significance of preven-tive measures against psychiatric disorders in patients with fatty liver disease.

Socioeconomic traits and the risk of Barrett’s esophagus and gastroesophageal reflux disease: A Mendelian randomization study

BACKGROUND Previous observational studies have shown that the prevalence of gastroesophageal reflux disease(GERD)and Barrett’s esophagus(BE)is associated with socioeconomic status.However,due to the methodological limitations of traditional observational studies,it is challenging to definitively establish causality.AIM To explore the causal relationship between the prevalence of these conditions and socioeconomic status using Mendelian randomization(MR).METHODS We initially screened single nucleotide polymorphisms(SNPs)to serve as proxies for eight socioeconomic status phenotypes for univariate MR analysis.The inverse variance weighted(IVW)method was used as the primary analytical method to estimate the causal relationship between the eight socioeconomic status phenotypes and the risk of GERD and BE.We then collected combinations of SNPs as composite proxies for the eight socioeconomic phenotypes to perform multivariate MR(MVMR)analyses based on the IVW MVMR model.Furthermore,a two-step MR mediation analysis was used to examine the potential mediation of the associations by body mass index,major depressive disorder(MDD),smoking,alcohol consumption,and sleep duration.RESULTS The study identified three socioeconomic statuses that had a significant impact on GERD.These included household income[odds ratio(OR):0.46;95% confidence interval(95%CI):0.31-0.70],education attainment(OR:0.23;95%CI:0.18-0.29),and the Townsend Deprivation Index at recruitment(OR:1.57;95%CI:1.04-2.37).These factors were found to independently and predominantly influence the genetic causal effect of GERD.Furthermore,the mediating effect of educational attainment on GERD was found to be mediated by MDD(proportion mediated:10.83%).Similarly,the effect of educational attainment on BE was mediated by MDD(proportion mediated:10.58%)and the number of cigarettes smoked per day(proportion mediated:3.50%).Additionally,the mediating effect of household income on GERD was observed to be mediated by sleep duration(proportion mediated:9.75%)CONCLUSION This MR study shed light on the link between socioeconomic status and GERD or BE,providing insights for the prevention of esophageal cancer and precancerous lesions.

Causal relationship between circulating vitamin C and 25-hydroxyvitamin D concentrations and common mental disorders-a Mendelian randomization study

Mental disorders seriously affect people’s health and social stability.This Mendelian randomization(MR)study was designed to investigate the causal relationship between circulating vitamin C(VC)or 25-hydroxyvitamin D(25(OH)D)levels and mental disorders.The data used for the MR analysis were derived from the summary genome-wide association studies(GWAS)database for VC and 25(OH)D and from the Finn Gen consortium for fourteen mental disorders.Based on the inverse variance weighted(IVW)method,we found a potential causal association between circulating VC and anxiety disorders(IVW:OR=1.139,95%CI:1.023-1.269,P=0.018).However,no causal association was found between VC or 25(OH)D and other mental disorders(P>0.05).In the reverse MR analysis,individuals with Alzheimer’s disease was causally associated with higher concentrations of circulating VC(P=0.012),while individuals with anxiety disorders had a negative association between the concentrations of 25(OH)D(P=0.012).However,the current evidence does not support a causal relationship between VC or 25(OH)D and other mental disorders.In addition,there was no causal association between circulating VC and 25(OH)D(P>0.05).Future studies are needed to confirm these findings and to elucidate the mechanisms of potential causality.

Exploring the Impact of Alcohol Consumption and Smoking on Primary Open Angle Glaucoma: A Mendelian Randomization Study

Objective: Utilizing Mendelian Randomization, this study employs Single Nucleotide Polymorphisms (SNPs) as instrumental variables to explore the causal relationships between bibulosity, smoking, and Primary Open Angle Glaucoma (POAG). Methods: GWAS data for bibulosity, smoking, and POAG were obtained from the Social Science Genetic Association Consortium website and the IEU OpenGWAS Project website, respectively. Using a P-value threshold of −8, a linkage disequilibrium coefficient (r2) of 0.001, and a linkage disequilibrium region width of 10,000 kb, the data were aggregated, resulting in 6 SNPs for bibulosity and 253 SNPs for smoking. Three regression models, MR-Egger, Weighted Median Estimator (WME), and Random-Effects Inverse-Variance Weighted (IVW) were applied to analyze the causal impact of bibulosity and smoking on POAG. Results: The GWAS data for alcohol consumption and smoking were derived from European populations, while the GWAS data for Primary Open-Angle Glaucoma (POAG) were sourced from East Asian populations, with no gender restrictions. Analysis using three different regression models revealed that neither excessive alcohol consumption nor smoking significantly increased the risk of developing POAG. Specifically, the odds ratios with 95% confidence intervals for the alcohol consumption group were 0.854 (0.597 - 1.221) in MR-Egger regression, 0.922 (0.691 - 1.231) in WME regression, and 0.944 (0.711 - 1.252) in IVW regression. For the smoking group, the odds ratios were 1.146 (0.546 - 2.406) in MR-Egger regression, 0.850 (0.653 - 1.111) in WME regression, and 0.939 (0.780 - 1.131) in IVW regression. Given the significant heterogeneity in the SNPs associated with smoking, the focus was primarily on the results from the IVW regression model. Conclusion: Alcohol consumption and smoking are not significant risk factors for the development of POAG.

Different effects of 24 dietary intakes on gastroesophageal reflux disease: A mendelian randomization

BACKGROUND In observational studies,dietary intakes are associated with gastroesophageal re-flux disease(GERD).AIM To conduct a two-sample mendelian randomization(MR)analysis to determine whether those associations are causal.METHODS To explore the relationship between dietary intake and the risk of GERD,we extracted appropriate single nucleotide polymorphisms from genome-wide asso-ciation study data on 24 dietary intakes.Three methods were adopted for data analysis:Inverse variance weighting,weighted median methods,and MR-Egger's method.The odds ratio(OR)and 95%confidence interval(CI)were used to eva-luate the causal association between dietary intake and GERD.RESULTS Our univariate Mendelian randomization(UVMR)results showed significant evidence that pork intake(OR,2.83;95%CI:1.76-4.55;P=1.84×10–5),beer intake(OR,2.70,95%CI:2.00-3.64;P=6.54×10–11),non-oily fish intake(OR,2.41;95%CI:1.49-3.91;P=3.59×10–4)have a protective effect on GERD.In addition,dried fruit intake(OR,0.37;95%CI:0.27-0.50;6.27×10–11),red wine intake(OR,0.34;95%CI:0.25-0.47;P=1.90×10-11),cheese intake(OR,0.46;95%CI:0.39-0.55;P=3.73×10-19),bread intake(OR,0.72;95%CI:0.56-0.92;P=0.0009)and cereal intake(OR,0.45;95%CI:0.36-0.57;P=2.07×10-11)were negatively associated with the risk of GERD.There was a suggestive asso-ciation for genetically predicted coffee intake(OR per one SD increase,1.22,95%CI:1.03-1.44;P=0.019).Multi-variate Mendelian randomization further confirmed that dried fruit intake,red wine intake,cheese intake,and cereal intake directly affected GERD.In contrast,the impact of pork intake,beer intake,non-oily fish intake,and bread intake on GERD was partly driven by the common risk factors for GERD.However,after adjusting for all four elements,there was no longer a suggestive association between coffee intake and GERD.CONCLUSION This study provides MR evidence to support the causal relationship between a broad range of dietary intake and GERD,providing new insights for the treatment and prevention of GERD.

Serum urate is associated with an increased risk of inflammatory bowel disease: A bidirectional Mendelian randomization study

BACKGROUND Previous studies have indicated bidirectional associations between urate levels and inflammatory bowel disease(IBD),including ulcerative colitis(UC)and Crohn’s disease(CD).However,it remains unclear whether the observations are causal because of confounding factors.AIM To investigate the causal associations between urate levels and IBD using bidirec-tional Mendelian randomization(MR).METHODS Independent genetic variants for urate levels and IBD were selected as instru-mental variables from published genome-wide association studies(GWASs).Summary statistics for instrument-outcome associations were retrieved from three separate databases for IBD(the UK Biobank,the FinnGen database and a large GWAS meta-analysis)and one for urate levels(a large GWAS meta-analysis).MR analyses included the inverse-variance-weighted method,weighted-median estimator,MR-Egger and sensitivity analyses(MR-PRESSO).A meta-analysis was also conducted to merge the data from separate outcome databases using a fixed-effects model.RESULTS Genetically higher serum urate levels were strongly associated with an increased risk of UC[odds ratio(OR):1.95,95%confidence interval(CI):1.86-2.05]after outlier correction,and the ORs(95%CIs)for IBD and CD were 0.94(95%CI:0.86-1.03)and 0.91(95%CI:0.80-1.04),respectively.Animal studies have confirmed the positive association between urate levels and UC.Moreover,genetically predicted IBD was inversely related to urate levels(OR:0.97,95%CI:0.94-0.99).However,no association was observed between genetically influenced UC or CD and urate levels.CONCLUSION Urate levels might be risk factors for UC,whereas genetically predicted IBD was inversely associated with urate levels.These findings provide essential new insight for treating and preventing IBD.

Immune cell signatures and causal association with irritable bowel syndrome:A mendelian randomization study

BACKGROUND The mucosal barrier's immune-brain interactions,pivotal for neural development and function,are increasingly recognized for their potential causal and therapeutic relevance to irritable bowel syndrome(IBS).Prior studies linking immune inflammation with IBS have been inconsistent.To further elucidate this relationship,we conducted a Mendelian randomization(MR)analysis of 731 immune cell markers to dissect the influence of various immune phenotypes on IBS.Our goal was to deepen our understanding of the disrupted brain-gut axis in IBS and to identify novel therapeutic targets.AIM To leverage publicly available data to perform MR analysis on 731 immune cell markers and explore their impact on IBS.We aimed to uncover immunophenotypic associations with IBS that could inform future drug development and therapeutic strategies.METHODS We performed a comprehensive two-sample MR analysis to evaluate the causal relationship between immune cell markers and IBS.By utilizing genetic data from public databases,we examined the causal associations between 731 immune cell markers,encompassing median fluorescence intensity,relative cell abundance,absolute cell count,and morphological parameters,with IBS susceptibility.Sensitivity analyses were conducted to validate our findings and address potential heterogeneity and pleiotropy.RESULTS Bidirectional false discovery rate correction indicated no significant influence of IBS on immunophenotypes.However,our analysis revealed a causal impact of IBS on 30 out of 731 immune phenotypes(P<0.05).Nine immune phenotypes demonstrated a protective effect against IBS[inverse variance weighting(IVW)<0.05,odd ratio(OR)<1],while 21 others were associated with an increased risk of IBS onset(IVW≥0.05,OR≥1).CONCLUSION Our findings underscore a substantial genetic correlation between immune cell phenotypes and IBS,providing valuable insights into the pathophysiology of the condition.These results pave the way for the development of more precise biomarkers and targeted therapies for IBS.Furthermore,this research enriches our comprehension of immune cell roles in IBS pathogenesis,offering a foundation for more effective,personalized treatment approaches.These advancements hold promise for improving IBS patient quality of life and reducing the disease burden on individuals and their families.

Causal relationships between gut microbiota and dementia:A twosample,bidirectional,Mendelian randomization study

BACKGROUND Existing evidence suggests that gut microbiota represent a significant environmental risk factor for various forms of dementia,including Alzheimer's dementia,vascular dementia,and dementia in other diseases classified elsewhere.However,the exact causal relationships between gut microbiota and the different forms of dementia or their subtypes remain unclear.AIM To investigate putative causal relationships between gut microbiota and dementia or its subtypes using Mendelian randomization(MR)analysis.METHODS A bidirectional,two-sample,MR analysis was conducted utilizing publicly available gut microbiota-related genome-wide association study(GWAS)summary data from the MiBioGen consortium alongside GWAS summary statistics for dementia and its subtypes from the FinnGen consortium.Instrumental variables were selected according to the fundamental tenets of MR and their strengths were evaluated using the F-statistic.Five MR methods were employed,and the robustness of our findings was validated.To account for multiple comparisons,we applied the Bonferroni method for P-value adjustment.RESULTS We identified several gut microbiota taxa exhibiting putative causal relationships with dementia or its subtypes,potentially serving as risk or protective factors for the disease.In addition,reverse MR analysis indicated that the relative abundance of several gut microbiota taxa might be influenced by dementia or its subtypes.An exhaustive sensitivity analysis confirmed the absence of heterogeneity and horizontal pleiotropy.After applying correction for multiple testing,we observed that the order Bacillales(odds ratio:0.830,95%confidence interval:0.740-0.932,P=0.00155,Padjust=0.0311)exhibited a strong association with Alzheimer’s disease-related dementia.CONCLUSION The results suggest that gut microbiota is causally associated with dementia.Our findings provide novel insights into the pathophysiology of dementia and have important implications for its treatment and prevention.

Investigating the causal associations between five anthropometric indicators and nonalcoholic fatty liver disease:Mendelian randomization study

BACKGROUND Although the etiology of nonalcoholic fatty liver disease(NAFLD)has not been thoroughly understood,the emerging roles of anthropometric indicators in assessing and predicting the risk of NAFLD have been highlighted by accumulating evidence.AIM To evaluate the causal relationships between five anthropometric indicators and NAFLD employing Mendelian randomization(MR)design.METHODS The Anthropometric Consortium provided genetic exposure data for five anthropometric indicators,including hip circumference(HC),waist circumference(WC),waist-to-hip ratio(WHR),body mass index(BMI),and body fat percentage(BF).Genetic outcome data for NAFLD were obtained from the United Kingdom Biobank and FinnGen Consortium.Genome-wide significant single nucleotide polymorphisms were chosen as instrumental variables.Univariable MR(UVMR)and multivariable MR(MVMR)designs with analytical approaches,including inverse variance weighted(IVW),MR-Egger,weighted median(WM),and weighted mode methods,were used to assess the causal relationships between anthropometric indicators and NAFLD.RESULTS Causal relationships were revealed by UVMR,indicating that a higher risk of NAFLD was associated with a perunit increase in WC[IVW:odds ratio(OR)=2.67,95%CI:1.42-5.02,P=2.25×10^(−3)],and BF was causally associated with an increased risk of NAFLD(WM:OR=2.23,95%CI:1.07-4.66,P=0.033).The presence of causal effects of WC on the decreased risk of NAFLD was supported by MVMR after adjusting for BMI and smoking.However,no causal association between BF and NAFLD was observed.In addition,other causal relationships of HC,WHR(BMI adjusted),and BMI with the risk of NAFLD were not retained after FDR correction.CONCLUSION This study establishes a causal relationship,indicating that an increase in WC is associated with a higher risk of NAFLD.This demonstrates that a suitable decrease in WC is advantageous for preventing NAFLD.

Association between gut microbiota and hepatocellular carcinoma and biliary tract cancer:A mendelian randomization study

BACKGROUND An increasing number of studies have begun to discuss the relationship between gut microbiota and diseases,yet there is currently a lack of corresponding articles describing the association between gut microbiota and hepatocellular carcinoma(HCC)and biliary tract cancer(BTC).This study aims to explore the relationship between them using Mendelian randomization(MR)analysis method.AIM To assess the relationship between gut microbiota and HCC and BTC.METHODS We obtained Genome-wide association study(GWAS)data for the gut microbiome from the intestinal microbiota genomic library(MiBioGen,https://mibiogen.gcc.rug.nl/).Additionally,we accessed data pertaining to HCC and BTC from the IEU open GWAS platform(https://gwas.mrcieu.ac.uk/).Our analysis employed fundamental instrumental variable analysis methods,including inverse-variance weighted,MR and Egger.To ensure the dependability of the results,we subjected the results to tests for multiple biases and heterogeneity.RESULTS During our investigation,we discovered 11 gut microbiota linked to an increased risk to BTC and HCC.The former included the genus Eubacterium hallii group(P=0.017),Candidatus Soleaferrea(P=0.034),Flavonifractor(P=0.021),Lachnospiraceae FCS020(P=0.034),the order Victivallales(P=0.018),and the class Lentisphaeria(P=0.0.18).The latter included the genus Desulfovibrio(P=0.042),Oscillibacter(P=0.023),the family Coriobacteriaceae(P=0.048),the order Coriobacteriales(P=0.048),and the class Coriobacteriia(P=0.048).Furthermore,in BTC,we observed 2 protective gut microbiota namely the genus Dorea(P=0.041)and Lachnospiraceae ND3007 group(P=0.045).All results showed no evidence of multiplicity or heterogeneity.CONCLUSION This study explores a causal link between gut microbiota and HCC and BTC.These insights may enhance the mechanistic knowledge of microbiota-related HCC and BTC pathways,potentially informing therapeutic strategies.

Causal relationship between feelings and cognitive decline:An univariable and multivariable Mendelian randomization study

BACKGROUND While the impact of depression on cognition is well-documented,the relationship between feelings and cognition has received limited attention.AIM To explore the potential association between feelings and cognition with a twosample Mendelian randomization(MR)analysis.METHODS Our analysis utilized genome-wide association data on various feelings(fed-up feelings,n=453071;worrier/anxious feelings,n=450765;guilty feelings,n=45-0704;nervous feelings,n=450700;sensitivity/hurt feelings,n=449419;miserableness,n=454982;loneliness/isolation,n=455364;happiness,n=152348)in the European population and their impact on cognitive functions(intelligence,n=269867).Conducting a univariable MR(UVMR)analysis to assess the relationship between feelings and cognition.In this analysis,we applied the inverse variance weighting(IVW),weighted median,and MR Egger methods.Additionally,we performed sensitivity analysis(leave-one-out analysis),assessed heterogeneity(using MR-PRESSO and Cochran’s Q test),and conducted multiple validity test(employing MR-Egger regression).Subsequently,a multivariable MR(MVMR)analysis was employed to examine the impact of feelings on cognition.IVW served as the primary method in the multivariable analysis,complemented by median-based and MR-Egger methods.RESULTS In this study,UVMR indicated that sensitivity/hurt feelings may have a negative causal effect on cognition(OR=0.63,95%CI:0.43-0.92,P=0.017).After adjustment of other feelings using MVMR,a direct adverse causal effect on cognition was observed(OR_(MVMR)=0.39,95%CI:0.17-0.90,P_(MVMR)=0.027).While a potential increased risk of cognitive decline was observed for fed-up feelings in the UVMR analysis(ORUVMR=0.64,95%CI:0.42-0.97,PUVMR=0.037),this effect disappeared after adjusting for other feelings(OR_(MVMR)=1.42,95%CI:0.43-4.74,P_(MVMR)=0.569).These findings were generally consistent across MV-IVW,median-based,and MR-Egger analyses.MR-Egger regression revealed pleiotropy in the impact of worrier/anxious feelings on cognition,presenting a challenge in identifying the effect.Notably,this study did not demonstrate any significant impact of guilty feelings,nervous feelings,miserableness,or loneliness/isolation on cognition.Due to a limited number of instrumental variables for happiness,this study was unable to analyze the relationship between happiness and cognition.CONCLUSION This MR study finds that sensitivity/hurt feelings are associated with cognitive decline,while the link between worrier/anxious feelings and cognition remains inconclusive.Insufficient evidence supports direct associations between happiness,guilty feelings,nervous feelings,miserableness,loneliness/isolation,and cognition.

Effect of viral hepatitis on type 2 diabetes:A Mendelian randomization study

BACKGROUND The effects of viral hepatitis(VH)on type 2 diabetes(T2D)remain controversial.AIM To analyze the causal correlation between different types of VH and T2D using Mendelian randomization(MR).METHODS Single nucleotide polymorphisms of VH,chronic hepatitis B(CHB),chronic hepatitis C(CHC)and T2D were obtained from the BioBank Japan Project,European Bioinformatics Institute,and FinnGen.Inverse variance weighted,MREgger,and weighted median were used to test exposure-outcome associations.The MR-Egger intercept analysis and Cochran’s Q test were used to assess horizontal pleiotropy and heterogeneity,respectively.Leave-one-out sensitivity analysis was used to evaluate the robustness of the MR analysis results.RESULTS The MR analysis showed no significant causal relationship between VH and T2D in Europeans[odds ratio(OR)=1.028;95%confidence interval(CI):0.995-1.062,P=0.101].There was a negative causal association between CHB and T2D among East Asians(OR=0.949;95%CI:0.931-0.968,P<0.001),while there was no significant causal association between CHC and T2D among East Asians(OR=1.018;95%CI:0.959-1.081,P=0.551).Intercept analysis and Cochran’s Q test showed no horizontal pleiotropy or heterogeneity(P>0.05).Sensitivity analysis showed that the results were robust.CONCLUSION Among East Asians,CHB is associated with a reduced T2D risk,but this association is limited by HBV load and cirrhosis.Although VH among Europeans and CHC among East Asians are not associated with the risk of T2D,focusing on blood glucose in patients with CHC is still relevant for the early detection of T2D induced by CHCmediated pathways of hepatic steatosis,liver fibrosis,and cirrhosis.