Evaluating the potential role of pleiotropy in Mendelian randomization studies

Bidirectional Mendelian Randomization analysis of iron status and uremia: no evidence of a causal relationship

Iron status and uremia have been linked, but the causality remains ambiguous. This bidirectional study aimed to explore the causal association between genetically predicted iron status and uremia. Utilizing summary data from genome-wide association studies (GWAS) of iron status and uremia, a two-sample Mendelian Randomization (MR) design was employed. Iron status was assessed through serum iron (SI), serum ferritin (SF), total iron-binding capacity (TIBC), and transferrin saturation (TS), while uremia included renal failure and dialysis. The primary analysis was conducted using the Inverse Variance Weighted (IVW) method. Additional MR evaluation included the weighted median, weighted mode, simple mode, and MR-Egger regression methods. Sensitivity analysis included MR-Egger for pleiotropy, MR-PRESSO for detecting outliers, Cochran's Q test for heterogeneity, and leave-one-out analysis for robustness. Genetically determined iron status did not have a causal effect on the risk of uremia (renal failure or dialysis). The primary IVW results indicated no statistically significant relationship between iron status and uremia (all p > 0.05). Consistent results were found through various methods. Similarly, there were no significant causal effects of uremia on iron status (all p > 0.05). Heterogeneity was observed in some associations, but pleiotropy was generally not evident. This bidirectional MR study provides no evidence for a causal relationship between genetically predicted iron status and the risk of uremia. These findings challenge prior observational associations and highlight the need for further mechanistic and interventional studies to elucidate the complex interplay between iron metabolism and kidney disease.

Glucagon-like peptide-1 receptor agonists, inflammation, and kidney diseases: evidence from Mendelian randomization

OBJECTIVE

It has been proved that glucagon-like peptide-1 receptor (GLP1R) agonists have positive effects on renal outcomes in diabetic patients. However, it remains unknown whether GLP1R agonists could provide similar protection against other kidney diseases.

METHODS

We performed two-sample Mendelian randomization (MR) analyses to determine the causal effects of GLP1R agonists on multiple kidney diseases. Exposure to GLP1R agonist was proxied by the available cis-eQTLs for GLP1R. Primary outcomes included the risk assessment for diabetic nephropathy, IgA nephropathy, membranous nephropathy, nephrotic syndrome, chronic kidney disease, acute glomerulonephritis, chronic glomerulonephritis and calculus of kidney/ureter. Type 2 diabetes and body mass index were used as positive control. Two-stage network MR analyses were conducted to assess the mediation effect of inflammatory proteins on the relationships between GLP1R agonists and kidney diseases.

RESULTS

After meta-analyses of both discovery and validation cohorts, genetically proxied GLP1R agonist was found to significantly associated with a decreased risk of diabetic nephropathy (OR = 0.72, 95%CI = 0.54-0.97, p = 0.031) and IgA nephropathy (OR = 0.58, 95%CI = 0.36-0.94, p = 0.027). Two-stage network MR revealed that there was an indirect effect of GLP1R agonist on IgA nephropathy through signaling lymphocytic activation molecule family member 1 (SLAMF1), with a mediated proportion of 34.27% (95% CI, 1.47-67.03%, p = 0.041) of the total effect.

CONCLUSIONS

The findings of current study presented genetic proof for the potential protective effects of GLP1R agonists in the development of diabetic nephropathy and IgA nephropathy, offering a novel sight for future mechanistic and clinical applications.

A practical guide for nephrologist peer reviewers: understanding and appraising Mendelian randomization studies

Identifying risk factors for disease onset and progression has been a core focus in nephrology research. Mendelian Randomization (MR) has emerged as a powerful genetic epidemiological approach, utilizing genome-wide association studies (GWAS) to establish causal relationships between modifiable risk factors and kidney disease outcomes. MR uses genetic variants as instrumental variables to infer causal relationships between exposures and disease outcomes. This method leverages the natural randomization of genetic variants to balance confounders, akin to matched cohorts in observational research. The rapid increase in MR studies on kidney disease poses challenges for journals and peer reviewers, especially clinicians unfamiliar with the methodology. High-quality MR studies use strong, well-validated genetic instruments with clear biological relevance, thoroughly testing for pleiotropy and confounding factors using methods like MR-Egger. Sensitivity analyses, such as MR-PRESSO, should ensure findings remain consistent across various assumptions. Effect sizes with confidence intervals should be reported and discussed within established biological mechanisms. Additionally, limitations must be transparently addressed, with recommendations for replication in future studies, to strengthen findings. This article guides readers in understanding MR application in nephrology and identifying high-quality MR studies, helping peers avoid pitfalls while seizing new opportunities in advancing kidney disease research.

Educational attainment, body mass index, and smoking as mediators in kidney disease risk: a two-step Mendelian randomization study

BACKGROUND

Educational attainment (EA) has been linked to various health outcomes, including kidney disease (KD). However, the underlying mechanisms remain unclear. This study aims to assess the causal relationship between EA and KD and quantify the mediation effects of modifiable risk factors using a Mendelian randomization (MR) approach.

METHODS

We performed a two-sample MR analysis utilizing summary statistics from large-scale European genome-wide association studies (GWAS). EA (NGWAS = 766,345) was used as the exposure, and KD (Ncase/Ncontrol= 5,951/212,871) was the outcome. A two-step MR method was applied to identify and quantify the mediation effects of 24 candidate risk factors.

RESULTS

Each additional 4.2 years of genetically predicted EA was associated with a 32% reduced risk of KD (odds ratio [OR] 0.68; 95% confidence interval [CI] 0.56, 0.83). Among the 24 candidate risk factors, body mass index (BMI) mediated 21.8% of this protective effect, while smoking heaviness mediated 18.7%.

CONCLUSIONS

This study provides robust evidence that EA exerts a protective effect against KD, partially mediated by BMI and smoking. These findings highlight the potential for targeted public health interventions aimed at mitigating obesity and smoking-related risks to reduce KD incidence, particularly among individuals with lower educational attainment.

Causal associations between circulating metabolites and chronic kidney disease: a Mendelian randomization study

BACKGROUND

Circulating metabolites have been associated with cross-sectional renal function in population-based research. Nevertheless, there is currently little proof to support the idea that metabolites either cause or prevent renal function. New treatment targets and ways to screen individuals with impaired renal function will be made possible via an in-depth analysis of the causal relationship between blood metabolites and renal function.

METHODS

We assessed the causal relationship between 452 serum metabolites and six renal phenotypes (CKD, rapid progression to CKD [CKDi25], rapid eGFR decline [CKD rapid3], dialysis, estimated glomerular filtration rate, and blood urea nitrogen) using univariate Mendelian randomization, primarily employing the inverse variance weighted method with robust sensitivity analyses. Heterogeneity and pleiotropy were examined via Cochrane's Q test and MR-Egger regression, and statistical significance was adjusted using Bonferroni correction. To assess potential adverse effects of metabolite modulation, we conducted a phenome-wide Mendelian randomization analysis, followed by multivariate Mendelian randomization to adjust for confounders.

RESULTS

We identified glycine and N-acetylornithine as potential causal mediators of CKD and renal dysfunction. Notably, lowering glycine levels may increase the risk of cholelithiasis and cholecystitis, while reducing N-acetylornithine could have unintended effects on tinnitus.

CONCLUSION

Glycine and N-acetylornithine represent promising therapeutic targets for CKD and renal function preservation, but their modulation requires careful risk-benefit assessment to avoid adverse effects.

Proteomic insights into metabolic dysfunction-associated steatotic disease: Identifying therapeutic targets and assessing on-target side effects

AIMS

The prevalence of metabolic dysfunction-associated steatotic liver disease (MASLD) is rising sharply, yet treatment options remain inadequate. To uncover new therapeutic targets for MASLD, we conducted a comprehensive proteome-wide Mendelian randomization (MR) and phenome-wide association study (PheWAS).

MATERIALS AND METHODS

Discovery MR utilized protein quantitative trait loci (pQTL) data on 4907 plasma protein levels from 35,559 individuals, alongside genome-wide association study (GWAS) on MASLD from the Million Veteran Program (68,725 cases / 95,482 controls). Validation comprised five pairwise combinations of these discovery datasets with three additional datasets: pQTL data for 2923 proteins from the UK Biobank, and liver biopsy-confirmed MASLD GWAS (1483 cases/17,781 controls) and MRI-liver fat GWAS (31,377 subjects) (excluding discovery pair). Candidate proteins underwent druggability assessment and on-target side effect evaluation via PheWAS.

KEY FINDINGS

We identified 26 proteins associated with MASLD after Bonferroni correction (P < 1.16 × 10-5), with 19 of them showing no significant reverse association. Interleukin-6 (IL-6), alpha-1-antitrypsin (α1-antitrypsin), 5-hydroxytryptamine receptor 7 (5-HT7R), ephrin-B1 (EFNB1), and protein MENT (CA056) were replicated. Notably, IL-6 (OR = 2.02; 95 % CI 1.54-2.64), 5-HT7R (OR = 2.73; 95 % CI 1.96-3.80), and EFNB1 (OR = 1.82; 95 % CI 1.59-2.08) were positively associated with MASLD risk, whereas α1-antitrypsin (OR = 0.84; 95 % CI 0.78-0.90) and CA056 (OR = 0.90; 95 % CI 0.86-0.94) appeared protective. Among these, IL-6, 5-HT7R, and α1-antitrypsin were druggable. PheWAS identified potential cardiovascular side effects for 5-HT7R and α1-antitrypsin.

SIGNIFICANCE

The integrative study identified several plasma proteins associated with MASLD. IL-6, α1-antitrypsin, 5-HT7R, EFNB1 and CA056 deserve further investigation as potential drug targets for MASLD.

Association of Plasma Angiogenin With Risk of Incident End-Stage Kidney Disease in Individuals With Type 2 Diabetes

We investigated the association between plasma angiogenin and the risk of progression to end-stage kidney disease (ESKD) in patients with type 2 diabetes (T2D) and attempted to infer the causal relationship between plasma angiogenin and chronic kidney disease. A total of 1,863 outpatients with T2D were included in this prospective cohort study. ESKD was defined as a composite of progression to sustained estimated glomerular filtration rate (eGFR) <15 mL/min/1.73 m2, maintenance dialysis, or death due to renal causes. The secondary outcome was rapid kidney function decline defined as a eGFR decline of 5 mL/min/1.73 m2 or greater per year. Over a median follow-up of 9.3 years, 125 incident ESKD events were identified. Elevated plasma angiogenin levels were associated with an increased risk of incident ESKD (adjusted hazard ratio 1.25 [95% CI 1.01-1.55], per 1 SD) independent of cardiorenal risk factors including baseline eGFR and albuminuria. A high level of plasma angiogenin was also associated with an increased risk for rapid kidney function decline (adjusted odds ratio 1.31 [95% CI 1.07-1.61], per 1 SD). A two-sample Mendelian randomization approach suggested a potential causal relationship between plasma angiogenin and chronic kidney disease. Plasma angiogenin may be a novel biomarker and potential therapeutic target for progressive kidney disease in patients with T2D.

ARTICLE HIGHLIGHTS

We investigated the association of plasma angiogenin with the risk of incident end-stage kidney disease (ESKD) in patients with type 2 diabetes. A high level of plasma angiogenin is independently associated with an increased risk for incident ESKD. A two-sample Mendelian randomization analysis suggested angiogenin may be causally involved in pathogenesis of chronic kidney disease. Plasma angiogenin may be a novel biomarker and potential therapeutic target for treatment of progressive kidney disease in patients with diabetes.

Genetic evidence for the effects of glucokinase activation on frailty-related outcomes: A Mendelian randomisation study

AIMS

We aimed to use the Mendelian randomisation (MR) design to investigate the potential causal effects of glucokinase (GK) activation on frailty-related outcomes and to explore the potential mediating effects of metabolic and inflammatory biomarkers.

MATERIALS AND METHODS

Seventeen independent single-nucleotide polymorphisms (SNPs) located within the GCK gene and significantly correlated with the glycated haemoglobin (HbA1c) level were used as genetic proxies for the effect of GK activation. We employed two-sample MR analysis to assess the relationship between genetically proxied GK activation and multifactorial frailty-related outcomes (frailty index, grip strength, walking pace, appendicular lean mass [ALM] and telomere length) We also explored the potential mediating effects using two-step MR.

RESULTS

Genetically proxied GK activation was significantly associated with a lower frailty index (beta: -0.161 per 1% decrease in HbA1c level due to GK activation, 95% confidence interval: -0.282 to -0.040, false discovery rate-adjusted p = 0.011). Additionally, GK activation showed significant associations with increased grip strength, higher ALM, faster walking pace and longer telomere length. GK activation also demonstrated a significant indirect effect on total grip strength and telomere length by reducing C-reactive protein levels (proportion of mediation: 6.79% to 8.21%).

CONCLUSION

Our study provides genetic evidence supporting the causal effects of GK activation on lowering the risk of frailty. These findings suggest that GK activators (GKAs) may aid in the management of frailty and sarcopaenia in people with diabetes; however, future randomized controlled trials are necessary to validate these results and establish their clinical applicability.

Examining socioeconomic differences in sepsis risk and mediation by modifiable factors: a Mendelian randomization study

BACKGROUND

Educational attainment is inversely related to sepsis risk, but the causal nature is still unclear. We therefore conducted the first Mendelian randomization (MR) study of genetically predicted educational attainment on sepsis that also uses a within-family genetic instrument for education. To further explore possible mechanistic pathways that can inform strategies to reduce sepsis risk, we examined the mediating effects of factors that are modifiable or can be prevented.

METHODS

The association between genetically predicted educational attainment and sepsis was estimated using summary-level data from recent genome-wide association studies. Possible bias due to population stratification, dynastic effects, and assortative mating in the genetic instrument for education was evaluated using summary-level data from a within-sibship genome-wide association study. We used inverse variance weighted MR analysis to estimate the effect of one standard deviation increase in years of education on sepsis risk. The robustness of the findings was assessed in sensitivity analyses, applying weighted median, weighted mode, and MR Egger regression. Finally, we applied multivariable MR analyses to estimate the mediating effects of smoking initiation, alcohol consumption, body mass index, high-density lipoprotein (HDL)-cholesterol, systolic blood pressure and type 2 diabetes.

RESULTS

For each standard deviation increase in genetically predicted educational attainment (3.4 years), the odds ratio (OR) for sepsis was 0.72 (95% confidence interval (CI) 0.66 to 0.78). The results of the analysis using the within-sibship genetic instrument and other sensitivity analyses were in line with this finding: within-sibship OR 0.88 (95% CI 0.64 to 1.18), weighted median OR 0.70 (95% CI 0.62 to 0.80), weighted mode OR 0.70 (95% CI 0.43 to 1.13), and MR Egger OR 0.65 (95% CI 0.50 to 0.85). The mediation analysis showed that 56% of the effect of educational attainment on sepsis risk can be explained by modifiable or preventable factors.

CONCLUSIONS

Higher educational attainment is strongly associated with a reduced risk of sepsis, pointing to important socioeconomic differences in this disease. The results also suggest that interventions targeting modifiable or preventable factors could contribute to reducing the socioeconomic differences in sepsis risk.

Exploring the causal relationship between Hashimoto thyroiditis and metabolic-associated fatty liver disease: A Mendelian randomization study

This study aims to investigate the possible causal link between Hashimoto thyroiditis (HT), an autoimmune disorder, and metabolic-associated fatty liver disease (MAFLD), previously referred to as nonalcoholic fatty liver disease (NAFLD), a common metabolic condition. Using genome-wide association study data from large European populations, we performed a bidirectional Mendelian randomization (MR) analysis. We identified single nucleotide polymorphisms strongly associated with HT and MAFLD/NAFLD, which we used as instrumental variables to probe the causal relationship between these 2 conditions. The forward MR analysis, using the inverse variance weighted method, showed that HT may increase the risk of MAFLD/NAFLD (odds ratio = 1.065, 95% confidence intervals: 1.014-1.119, P = .011). However, the reverse MR analysis did not establish a significant causal effect of MAFLD/NAFLD on HT (P > .05). Sensitivity analyses were carried out to assess potential heterogeneity or pleiotropy, and the results supported the robustness of our findings, indicating no significant concerns. These results suggest that HT may be a risk factor for the development of MAFLD/NAFLD. The bidirectional MR study revealed an elevated risk of MAFLD/NAFLD in individuals with HT, but no causal relationship was found from MAFLD/NAFLD to HT in the opposite direction. This understanding could assist healthcare professionals in improving their comprehension and management of both HT and MAFLD/NAFLD, leading to more comprehensive clinical guidance for patients and promoting the development of interdisciplinary treatment strategies.

The impact of educational attainment on gestational diabetes mellitus is mediated by body mass index: A Mendelian randomization study

Gestational diabetes mellitus (GDM) is a common pregnancy complication associated with adverse maternal and neonatal outcomes. While numerous studies have investigated the factors influencing GDM, the relationship between educational attainment and the GDM risk remains less explored. This study employs a Mendelian randomization (MR) approach to estimate the causal relationship between educational attainment, as a proxy for socioeconomic inequality, and the risk of GDM, and to quantify the roles of body mass index (BMI) as a potential mediator. We performed a two-sample MR study of genetically predicted educational attainment (instrumented using 1271 variants from 766,345 individuals) and gestational diabetes mellitus (116,363 individuals) using the largest genome-wide association studies. We used a two-step MR to quantify the proportion of education's effect on GDM mediated by BMI (681,275 individuals). Each standard deviation increase in educational attainment (4.2 years of schooling) was protective of GDM (odds ratios: 0.67; 95% confidence intervals [CI]: 0.59, 0.76). Higher educational attainment was also protective for BMI [β = -0.27 standard deviation (~1.3 kg/m2); 95% CI: -0.32, -0.22]. BMI mediated 35% (95% CI: 25%, 46%) of the total effect of education on GDM. Higher educational attainment has a protective effect on GDM risk. Interventions to reduce excess adiposity at the population level may reduce this risk, but the effect of education on GDM remains largely unexplained. Further investigation is necessary to identify additional risk factors that function as potentially modifiable mediators.

Mendelian randomization analysis reveals the potential of the IKZF1 gene as a therapeutic target in colorectal cancer

INTRODUCTION

Colorectal cancer (CRC) is a global health burden, highlighting the urgent need for the discovery of new biomarkers and therapeutic targets. This study integrates genetic epidemiology methods, such as Mendelian randomization (MR), with GWAS data to predict treatment efficacy and identify novel CRC therapeutic targets.

METHODS

We utilized cis-eQTL data from the eQTLGen consortium and CRC GWAS data from the IEU Open GWAS database. MR analysis was conducted via the R package TwoSampleMR. Bayesian colocalization analysis was applied to identify shared genetic effects between CRC risk factors and potential therapeutic targets. Phenome-wide association study (PheWAS), protein-protein interaction (PPI) network construction, and enrichment analyses were performed to elucidate the functional profiles of the targets. Molecular docking and dynamics simulations were employed to evaluate the therapeutic potential of the identified targets.

RESULTS

MR analysis identified 60 genes associated with CRC risk. Our analysis identified IKZF1 as a significant therapeutic target through colocalization analysis. The PheWAS results revealed no significant genomic correlations for IKZF1, suggesting its potential as a specific therapeutic target. PPI and enrichment analyses highlighted the role of IKZF1 in epigenetic regulation and transcriptional control. Molecular docking and dynamics simulations confirmed the strong binding affinities of potential drugs with IKZF1.

CONCLUSION

This study identified IKZF1 as a promising therapeutic target for CRC through MR and colocalization analyses. The target's association with immune modulation and epigenetic mechanisms, supported by molecular docking and dynamics simulations, positions IKZF1 as a key player in advancing precision CRC therapies, warranting further clinical investigation.

Schizophrenia, bipolar disorder and major depressive disorder are probably not risk factors for cardiovascular disease: A Mendelian randomized study

BACKGROUND

Individuals with severe mental illnesses (SMI) like schizophrenia, bipolar disorder (BD), and major depressive disorder (MDD) have an increased risk for cardiovascular diseases (CVD), but the causal relationship remains unclear.

METHODS

Mendelian randomization (MR) was used to investigate the potential causal relationship between SMI and CVD and its five subtypes of disease, coronary heart disease, myocardial infarction, stroke, heart failure, and atrial fibrillation. Subsequently, the MR results of SMI with CVD and its subtypes were meta-analyzed separately. To assess the robustness of the findings, Cochran's Q test, MR-Egger intercept test, MR-PRESSO, and leave-one-out analysis were used. Select single nucleotide polymorphisms (SNPs) related to SMI and CVD and their five subtypes (coronary heart disease, myocardial infarction, stroke, heart failure, and atrial fibrillation). Use univariable Mendelian randomization (UVMR) and multivariate Mendelian randomization (MVMR) to assess the causal relationship between these conditions. Conduct a meta-analysis of the MR results of SMI and CVD and their subtypes. Use MR mediation analysis to evaluate the mediating effect of BMI between BD and CVD. Use Cochran's Q test, MR-Egger intercept test, MR-PRESSO, and leave-one-out analysis to enhance the robustness of the study.

RESULTS

MR analyses have revealed correlations between schizophrenia and BD with CVD and their subtypes in certain datasets. No significant evidence of an association between MDD and CVD or its subtypes was observed in our MR analyses. After MVMR and MR meta-analysis, no basis for genetically predicted SMI increasing CVD and their subtypes was found. The MR mediation analysis showed that the reduced risk of certain CVDs in BD was partially related to BMI to some extent.

CONCLUSION

Our MR study did not provide conclusive evidence for a causal association between genetic predisposition to SMI and CVD. Based on the available evidence, it would be more appropriate to consider SMI as potential risk markers for CVD and its subtypes rather than definitive risk factors.

Major depressive disorder and the development of cerebral small vessel disease: A Mendelian randomization study

BACKGROUND

Although observational studies indicate a complex, bidirectional association between major depressive disorder (MDD) and cerebral small vessel disease (CSVD), the results are frequently inconsistent. This study investigated the potential correlation of MDD with both CSVD clinical outcomes and radiological markers, utilizing a bidirectional Mendelian randomization (MR) study design.

METHODS

Instrumental variables for MDD were obtained from the latest and largest genome-wide association study (GWAS). For CSVD, we extracted genetic instruments from GWAS datasets corresponding to both clinical outcomes and radiological markers, including intracerebral hemorrhage, small vessel ischemic stroke, white matter hyperintensities volume, mean diffusivity (MD), fractional anisotropy, brain microbleeds, and enlarged perivascular space (PVS). We employed the inverse variance weighting method as the primary analysis, complemented by conducting extensive sensitivity and heterogeneity tests.

RESULTS

In the forward MR analyses, we discovered that the genetically predicted risk of MDD exhibits a potential causal relationship with two CSVD phenotypes demonstrating microscopic white matter (WM) damage: mean diffusivity (β = 0.784, 95 % CI 0.285-1.283, p = 0.002) and WM-PVS (OR = 1.053, 95%CI 1.010-1.097, p = 0.015). A single SNP (rs2232423) was identified as significantly influencing the causal relationship between MDD and WM. After excluding this SNP, our estimated association between MDD and increased MD (β = 0.516, 95%CI -0.001-1.033, p = 0.048) remained. The effects of MDD on WM-PVS passed all the tests for heterogeneity and pleiotropy. Reverse MR analyses showed no evidence of reverse causality between MDD and an altered CSVD risk.

CONCLUSIONS

This study supports a potential causal association between MDD and CSVD-related indicators of impaired WM microstructure. These insights hold promise for improving risk assessment methods in CSVD.

Dissecting immune-mediated pathways in rheumatoid arthritis: A multivariate mediation analysis of antibodies and circulating proteins

Rheumatoid arthritis (RA) is a chronic inflammatory disorder with complex etiologies involving immune responses and circulating proteins. This study investigates the causal relationships between antibody immune responses, plasma circulating proteins, and the development of RA using Mendelian Randomization (MR) analysis; A two-sample and multivariate MR analysis was conducted to explore the mediating causal relationship between 46 antibody immune responses and RA through 4,907 plasma circulating proteins. Genetic variations were utilized as instrumental variables (IVs) to infer causality, ensuring that they met the assumptions of relevance, independence, and exclusion restriction. Data were sourced from the FinnGen R10 dataset, UK Biobank, and the SomaScan platform, providing a robust foundation for the analysis. Statistical methods including IVW, weighted median, and mode-based approaches were employed, complemented by sensitivity analyses to ensure the robustness of the findings; The study identified significant causal relationships between six antibody immune responses and RA, with three specific responses-Epstein-Barr virus EBNA-1, Epstein-Barr virus ZEBRA, and Anti-polyomavirus 2 IgG seropositivity-showing strong associations. However, reverse causality was detected for EBNA-1 and ZEBRA, leading to their exclusion from further analysis. Additionally, 12 plasma circulating proteins were found to have significant causal relationships with RA, with KCNIP3 emerging as a key protective factor. Multivariate MR analysis revealed that KCNIP3 mediates the relationship between Anti-polyomavirus 2 IgG seropositivity and RA, suggesting a potential protective mechanism. This study highlights the intricate relationships between specific antibody responses, circulating proteins, and RA risk. The findings suggest that certain proteins, particularly KCNIP3, may mediate the effects of immune responses on RA development, offering potential targets for therapeutic intervention.

Causal relationships between depression, anxiety, and myopia: a two-sample Mendelian randomization study

OBJECTIVES

To investigate the causal relationship between depression, anxiety, and myopia.

METHODS

The multivariable Mendelian randomization (MR) design using summary statistics from independent genome-wide association studies (GWAS) was employed. The anxiety and depression, were used as exposures, and myopia was used as the outcome. Genetic variants associated with depression were derived using GWAS summary statistics from the FinnGen consortium database. Genetic variants associated with anxiety were derived from the Psychiatric Genomics consortium. The inverse-variance-weighted method was the main applied analytic tool and was complemented with comprehensive sensitivity analyses.

RESULTS

A total of 21, 10 SNPs were selected as instrumental variables for depression and anxiety, respectively. Based on the IVW analysis, both depression (OR = 1.010, 95% CI = 1.002-1.018, P = 0.016) and anxiety (OR = 1.083, 95%CI = 1.022-1.149, P = 0.008) increased the risk of myopia. After adjusting in the multivariable MR, the IVW and Egger methods indicated that depression (OR = 1.004, 95%CI = 1.000-1.008, P = 0.030) or anxiety (OR = 1.004, 95%CI = 1.001-1.008, P = 0.026) was still associated with elevated risks of myopia.

CONCLUSIONS

The current study identified a causal relationship between anxiety, depression, and an increased risk of myopia. These observations suggest that when developing strategies to control myopia, it is also important to focus on the mental health of children. Further detailed research is needed to fully understand this issue.

Deciphering the influence of socioeconomic status on brain structure: insights from Mendelian randomization

Socioeconomic status (SES) influences physical and mental health, however its relation with brain structure is less well documented. Here, we examine the role of SES on brain structure using Mendelian randomisation. First, we conduct a multivariate genome-wide association study of SES using educational attainment, household income, occupational prestige, and area-based social deprivation, with an effective sample size of N = 947,466. We identify 554 loci associated with SES and distil these loci into those that are common across those four traits. Second, using an independent sample of ~35,000 we provide evidence to suggest that SES is protective against white matter hyperintensities as a proportion of intracranial volume (WMHicv). Third, we find that differences in SES still afford a protective effect against WMHicv, independent of that made by cognitive ability. Our results suggest that SES is a modifiable risk factor, causal in the maintenance of cognitive ability in older-age.

Obesity Phenotypes Causally Affect Cardiac MRI Structure and Induced Non-ischaemic Cardiomyopathy

Background

The growing obesity epidemic highlights the need to understand how various obesity phenotypes affect myocardial structure and increase non-ischaemic cardiomyopathy (NICM) incidence. The aim of this study was to investigate the causal effect of eight obesity-related traits on NICM and 16 cardiac MRI parameters. Potential mediators between obesity and NICM were also investigated.

Methods

Two-sample Mendelian randomisation was used to explore the causal relationship between eight obesity-related traits and NICM and assess their impact on cardiac MRI indicators. The study also used validation dataset analysis and multivariable Mendelian randomisation to ensure robustness, and mediation Mendelian randomisation analysis to identify metabolic markers as potential mediators.

Results

All eight obesity-related traits demonstrated a causal relationship with NICM, with the relationship between BMI and NICM persisting after adjustment for LDL cholesterol, urate level and hypertension (HTN). These traits also influenced arterial and cardiac structure and function, especially with regard to left ventricular mass. HTN was identified as a significant mediator, with a mediation effect ratio of 31%.

Conclusion

There is a robust causal association between obesity and NICM, and with abnormalities in myocardial structure and function. HTN emerges as a pivotal mediator in the obesity-NICM pathway, underscoring the critical role of managing obesity and HTN in preventing NICM progression.

New therapeutic targets and mechanisms of papillary thyroid carcinoma identified by multi-omics analysis

INTRODUCTION

The treatment of papillary thyroid carcinoma (PTC) presents ongoing challenges, underscoring the need for novel therapeutic targets.

METHODS

This study employed proteomic MR analysis, utilizing publicly available data from genome-wide association studies (GWAS) and protein quantitative trait loci (pQTL) studies. We analyzed proteomic data from deCODE and the UK Biobank Protein Project (UKB-PP), along with GWAS data on papillary thyroid carcinoma (PTC) from the Finnish Consortium. This analysis was further supported by eQTL validation and bioinformatics differential analysis to identify potential therapeutic targets for PTC. Additionally, we explored possible downstream mechanisms of the target proteins through mediation analysis.

RESULTS

Our analysis identified two potential therapeutic targets associated with PTC, specifically, LY75 and S100A12. Mediation analysis further investigated their potential mechanistic role in the pathogenesis of PTC.

CONCLUSION

Through multi-omics analysis, we identified new potential therapeutic targets for papillary thyroid carcinoma and investigated their possible underlying mechanisms affecting PTC.

Genome-wide analyses of variance in blood cell phenotypes provide new insights into complex trait biology and prediction

Blood cell phenotypes are routinely tested in healthcare to inform clinical decisions. Genetic variants influencing mean blood cell phenotypes have been used to understand disease aetiology and improve prediction; however, additional information may be captured by genetic effects on observed variance. Here, we mapped variance quantitative trait loci (vQTL), i.e. genetic loci associated with trait variance, for 29 blood cell phenotypes from the UK Biobank (N ~ 408,111). We discovered 176 independent blood cell vQTLs, of which 147 were not found by additive QTL mapping. vQTLs displayed on average 1.8-fold stronger negative selection than additive QTL, highlighting that selection acts to reduce extreme blood cell phenotypes. Variance polygenic scores (vPGSs) were constructed to stratify individuals in the INTERVAL cohort (N ~ 40,466), where the genetically most variable individuals had increased conventional PGS accuracy (by ~19%) relative to the genetically least variable individuals. Genetic prediction of blood cell traits improved by ~10% on average combining PGS with vPGS. Using Mendelian randomisation and vPGS association analyses, we found that alcohol consumption significantly increased blood cell trait variances highlighting the utility of blood cell vQTLs and vPGSs to provide novel insight into phenotype aetiology as well as improve prediction.

Unveiling new insights into migraine risk stratification using machine learning models of adjustable risk factors

BACKGROUND

Migraine ranks as the second-leading cause of global neurological disability, affecting approximately 1.1 billion individuals worldwide with severe quality-of-life impairments. Although adjustable risk factors-including environmental exposures, sleep disturbances, and dietary patterns-are increasingly implicated in pathogenesis of migraine, their causal roles remain insufficiently characterized, and the integration of multimodal evidence lags behind epidemiological needs.

METHODS

We developed a three-step analytical framework combining causal inference, predictive modeling, and burden projection to systematically evaluate modifiable factors associated with migraine. First, two-sample mendelian randomization (MR) assessed causality between five domains (metabolic profiles, body composition, cardiovascular markers, behavioral traits, and psychological states) and the risk of migraine. Second, we trained ensemble machine learning (ML) algorithms that incorporated these factors, with Shapley Additive exPlanations (SHAP) value analysis quantifying predictor importance. Finally, spatiotemporal burden mapping synthesized global incidence, prevalence, and disability-adjusted life years (DALYs) data to project region-specific risk and burden trajectories through 2050.

RESULTS

MR analyses identified significant causal associations between multiple adjustable factors (including overweight, obesity class 2, type 2 diabetes [T2DM], hip circumference [HC], body mass index [BMI], myocardial infarction, and feeling miserable) and the risk of migraine (P < 0.05, FDR-q < 0.05). The Random Forest (RF)-based model achieved excellent discrimination (Area under receiver operating characteristic curve [AUROC] = 0.927), identifying gender, age, HC, waist circumference [WC], BMI, and systolic blood pressure [SBP] as the predictors. Burden mapping projected a global decline in migraine incidence by 2050, yet persistently high prevalence and DALYs burdens underscored the urgency of timely interventions to maximize health gains.

CONCLUSIONS

Integrating causal inference, predictive modeling, and burden projection, this study establishes hierarchical evidence for adjustable migraine determinants and translates findings into scalable prevention frameworks. These findings bridge the gap between biological mechanisms, clinical practice, and public health policy, providing a tripartite framework that harmonizes causal inference, individualized risk prediction, and global burden mapping for migraine prevention.

The Relationship Between Serum Uric Acid and Gynecologic Cancer Risk: A Mendelian Randomization Study

Aim

High serum uric acid (UA) levels have been linked to cancer development through chronic inflammation and oxidative damage. Traditional epidemiological studies have shown inconsistent results regarding the relationship between uric acid and gynecological cancers. This study uses Mendelian randomization (MR) to explore the potential association between serum UA levels and various gynecological cancers.

Methods

In this two-sample MR study, summary statistical data of the genome-wide association studies (GWASs) on serum UA levels were extracted from the UK Biobank (UKB), and those on gynecological cancers were obtained from the FinnGen consortium, the Epidemiology of Endometrial Cancer Consortium (E2C2), and the Ovarian Cancer Association Consortium (OCAC). Inverse variance weighted (IVW), weighted median, MR-Egger, weighted mode, MR-Pleiotropy RESidual Sum and Outlier (MR-PRESSO), and MR-Radial methods were utilized to investigate the bidirectional causal associations of serum UA levels with gynecological cancers. The evaluation indexes were odds ratios (ORs) and confidence intervals (CIs). Tests for horizontal pleiotropism and heterogeneity of instrumental variables (IVs) were performed, respectively using MR-Egger test and Cochran's Q statistics. In addition, leave-one-out and MR scatter plots were employed for sensitivity analyses.

Results

IVW estimates suggested that serum UA levels elevated 1 unit had a potential causal association with higher odds of both cervical cancer (CC) (OR=1.147, 95% CI: 1.020-1.290) and invasive mucinous ovarian cancer (IMOC) (OR=1.199, 95% CI: 1.033-1.393). Also, endometrial carcinoma (EC) had a potential causal association with it (OR=1.012, 95% CI: 1.000-1.024). Additionally, sensitivity analyses showed the potential causal associations between UA and CC/IMOC were relatively robust.

Conclusion

An elevated serum UA level had potential associations with CC and IMOC, whereas patients with EC should pay attention to it in clinical practice, which may reduce the potential risk of gynecological cancers. However, further evidence is needed to clarify the true relationships between UA and gynecological cancers.

Exploring the causal association between fatty acid-binding proteins and anaphylactic shock due to adverse reactions to medications: A two-sample Mendelian randomization study

Previous studies have identified a relationship between fatty acid-binding proteins (FABPs) and immune diseases. This study aimed to investigate whether a causal relationship exists between FABPs and anaphylactic shock resulting from adverse drug reactions. Single nucleotide polymorphisms associated with FABPs were utilized as instrumental variables, sourced from the National Human Genome Research Institute-European Bioinformatics Institute Catalog of human genome-wide association studies. Data on anaphylactic shock due to adverse effects of correctly administered drugs were obtained from the FinnGen database, which includes genomic and health data from 500,000 Finnish biobank donors. A two-sample Mendelian randomization analysis was conducted to explore the causality between FABPs and anaphylactic shock due to adverse drug reactions. The analysis revealed a negative causal relationship between FABP5 (odds ratio [OR] = 0.40; 95% confidence interval [CI] = 0.17-0.92; P = .032) and FABP12 (OR = 0.77; 95% CI = 0.63-0.94; P = .009) and anaphylactic shock due to adverse drug reactions. These findings were corroborated by Mendelian randomization-Egger, weighted median, and weighted mode methods. This study provides robust evidence supporting a protective relationship between FABP5 and FABP12 and anaphylactic shock due to adverse drug reactions. Further experimental studies are warranted to elucidate the causal mechanisms and associations between FABP5, FABP12, and anaphylactic shock in the context of adverse drug reactions.

Insights into modifiable risk factors of retinal vascular occlusion: A Mendelian randomization study

Understanding the etiological risk factors for retinal vascular occlusion (RVO) is critical for prevention and treatment. While the effects of cardiovascular events, hypertension, glaucoma, obesity and glycemic risk factors on RVO are still controversial. This study employed two-sample Mendelian randomization (MR) analysis to investigate these causal risk factors. Single-nucleotide polymorphisms (SNPs) were used as instrumental variables (IVs). Genetic instruments for hypertension, glaucoma, obesity, cardiovascular events and glycemic risk factors were obtained from published genome-wide association studies (GWASs). Summary-level data for RVO and hypertension were obtained from the FinnGen consortium. MR analysis primarily utilized the inverse variance weighted (IVW) method, with MR-Egger and weighted median as supplementary approaches. Multivariable MR (MVMR) adjusting for hypertension or glaucoma of RVO were conducted. Heterogeneity was assessed using Cochrane's Q test and I2, while MR-Egger intercept and MR-PRESSO tested horizontal pleiotropy. All MR analyses were performed within R software (4.1.3) using the R packages "TwoSampleMR" and "MR-PRESSO." Genetic instruments for hypertension and glaucoma were significantly associated with RVO risk. A one-standard deviation (SD) increase in hypertension was associated with a higher risk of RVO [OR = 1.577, 95% CI = (1.342, 1.854), P < .001], while a one-SD increase in the log odds of genetically predicted glaucoma was associated with a higher risk of RVO [OR = 1.24, 95% CI = (1.115, 1.379), P < .001]. Meanwhile, hypertension and glaucoma were still significant in multivariable MR. There was not sufficient evidence to suggest cardiovascular events and obesity were associated with RVO risk. This MR study provided genetic evidence supporting that hypertension and glaucoma were causally associated with the risk of RVO. It may help guide clinical decisions in the management of RVO patients with hypertension and glaucoma.

Molecular crosstalk and potential causal mechanisms of rheumatoid arthritis and sarcopenia co-morbidity: A gene integration analysis

INTRODUCTION

Rheumatoid arthritis (RA) promotes the onset and progression of sarcopenia, yet mechanisms of co-morbidity between RA and sarcopenia are under-explored. Therefore, this study integrated Gene Expression Omnibus (GEO) and Genome-wide association studies (GWAS) data to comprehensively identify shared genes, associated mechanisms, and biological pathways in RA and sarcopenia.

METHODS

Utilizing two GEO datasets-GSE226151, which includes 60 RNA-seq samples of skeletal muscle from healthy aged, pre-sarcopenia, and sarcopenia individuals, and GSE55235, with 20 RNA-seq samples of synovial tissue from healthy and RA joints-we performed differentially expressed genes analysis, weighted gene co-expression network analysis to identify crosstalk genes in RA and sarcopenia, and enrichment analysis for these genes. Using relevant GWAS datasets, SMR analyses and cis-eQTL analyses were performed. We further validated and identified key crosstalk genes and explored potential causal associations between key crosstalk genes and RA and sarcopenia-related traits.

RESULTS

We identified 25 crosstalk genes shared between RA and sarcopenia, which are involved in immune-inflammatory response pathways, including neutrophil extracellular trap formation and Fc gamma receptor-mediated phagocytosis. SMR analysis further identified six core crosstalk genes: NCF1, FCGR2A, FCGR3A, SORL1, FCGR3B, and ITGAX (PSMR < 0.05). cis-eQTL analysis showed that FCGR2A might have a negative causal association with appendicular lean mass, whole body fat-free mass, and a positive causal association with RA (P < 0.05).

CONCLUSION

Overall, this study is the first to reveal the molecular crosstalk between RA and sarcopenia, identifying 25 shared genes and key immune-inflammatory response-related pathways. Further SMR and cis-eQTL analyses were conducted to validate six core genes, with FCGR2A emerging as a potential drug target for RA-associated sarcopenia. These findings provide new insights into the comorbid mechanisms of RA and sarcopenia, offering potential therapeutic targets for both conditions.

Endometriosis-Related Genetic Factors and Their Role in Preterm Birth: A Two-Sample Mendelian Randomisation Study

OBJECTIVE

Endometriosis affects 10% of women worldwide and is linked to adverse pregnancy outcomes, including preterm birth. Recent epidemiological and genetic studies indicate that endometriosis may influence gestational duration and the likelihood of preterm birth. This study aimed to estimate the direct genetic causal effects of endometriosis on gestational duration and preterm birth using Mendelian randomisation (MR) analysis, leveraging genetic data from recent genome-wide association studies (GWASs).

DESIGN

A two-sample MR study.

SETTING

Summary statistics from published GWASs on European ancestry populations for endometriosis and gestational duration.

POPULATION OR SAMPLE

Instrumental variables for endometriosis were derived from a meta-analysis comprising 60 674 endometriosis cases and 701 926 controls.

METHODS

Genetic correlations and heritability estimates were calculated using linkage disequilibrium score regression. Two-sample MR with multiplicative random-effects inverse variance weighting assessed the primary objectives, supplemented by sensitivity analyses to validate MR assumptions.

MAIN OUTCOME MEASURES

Primary outcomes were gestational duration and preterm birth, sourced from the latest GWAS data.

RESULTS

LD score regression revealed no genetic correlation between endometriosis and either gestational duration or preterm birth. MR analysis showed no causal association between endometriosis and maternal effects on offspring gestational duration (β = 0.40, 95% CI: -0.39 to 1.19, p = 0.32) or preterm birth (OR = 0.94, 95% CI: 0.82-1.06, p = 0.36). Sensitivity analyses indicated pleiotropy but no violations of MR assumptions. Of the four loci overlapping between the gestational duration and endometriosis GWASs, three (EBF1, WNT4, and GDAP1) were identified as outliers using MR-Presso.

CONCLUSIONS

Contrary to observational studies, MR analyses found no direct causal link between endometriosis and gestational duration or preterm birth. Overlaps in genomic regions suggest that the relationship may be mediated through different biological pathways.

Prioritization of potential drug targets in ovarian-related diseases: Mendelian randomization and colocalization analyses

OBJECTIVE

To identify key genes and potential drug targets for ovarian-related diseases through genome-wide Mendelian randomization (MR) and colocalization analyses.

DESIGN

We conducted a comprehensive two-sample MR analysis to estimate the causal effects of blood expression quantitative trait loci (eQTLs) on ovarian-related diseases, followed by colocalization analyses to verify the robustness of the expression instrumental variables (IVs). Phenome-wide association studies (PheWAS) were also performed to evaluate the horizontal pleiotropy of potential drug targets and possible side effects.

SUBJECTS

Large cohorts of European ancestry.

EXPOSURE

The exposure in this study was the genetic variants (eQTLs) associated with gene expression levels, considered a form of lifelong exposure. Expression quantitative trait loci data were obtained from the eQTLGen Consortium, encompassing 16,987 genes and 31,684 cis-eQTLs derived from blood samples of healthy individuals of European ancestry.

MAIN OUTCOME MEASURES

The primary outcome measures were the identification of genes causally associated with ovarian-related diseases and the validation of these genes as potential therapeutic targets.

RESULTS

Our study revealed that specific genes such as CD163L1, PPP3CA, MTAP, F12, NRM, BANK1, ZNF66, GNA15, and SLC6A9 were associated with ovarian endometriosis, ovarian cysts, and polycystic ovarian syndrome. Through MR and colocalization analyses, we identified potential drug targets, including CTNNB1, PTPN7, and ABCB4, with strong evidence of colocalization with ovarian-related diseases. Sensitivity analyses confirmed the robustness of our findings, showing no evidence of horizontal pleiotropy or heterogeneity.

CONCLUSION

This research highlights the significance of precision medicine approaches in identifying genetic factors underlying ovarian-related diseases and provides a foundation for developing targeted therapies, enhancing diagnostic accuracy, and improving treatment strategies for ovarian-related diseases.

Mendelian Randomization Assessment of the Genetic Effects of Lipid-Lowering Drugs on Digestive System Cancers

The relationship between lipid-lowering drugs and the risk of digestive system cancers remains unclear. This study aims to assess the risk association between lipid-lowering drugs and digestive system cancers through mendelian randomization (MR) analysis. We utilized genetic instruments to substitute for the exposure to lipid-lowering drugs, including expression quantitative trait loci (eQTL) for HMGCR, PCSK9, and NPC1L1, as well as genetic variants associated with low-density lipoprotein (LDL) from the Global Lipids Genetics Consortium's genome-wide association study (GWAS) data for target genes. We used MR and SMR methods to assess the risk estimates of lipid-lowering drug target genes on digestive system tumors. The MR analysis indicated a negative association between HMGCR-mediated LDL and hepatocellular carcinoma (OR = 0.06, 95% CI: 0.00-0.81, p = 0.03), and a positive association between NPC1L1-mediated LDL and gastric cancer risk (OR = 15.45, 95% CI: 5.96-40.56, p < 0.01). In the SMR analysis, it was observed that HMGCR expression decreased the risk of hepatocellular carcinoma (OR = 0.11, 95% CI: 0.02-0.68, p = 0.02), while NPC1L1 expression increased the risk of gastric cancer (OR = 1.33, 95% CI: 1.08-1.64, p < 0.01). Our study results suggested a potential risk association between HMGCR inhibitors and NPC1L1 with hepatocellular carcinoma and gastric cancer.

The Causality between Gut Microbiota and Hypertension and Hypertension-related Complications: A Bidirectional Two-Sample Mendelian Randomization Analysis

BACKGROUND

Recent studies have highlighted a connection between gut microbiota and hypertension, yet the precise nature of this relationship remains unclear.

OBJECTIVE

This research aims to analyze the causal link between gut microbiota and hypertension, along with associated complications, utilizing two-sample bidirectional Mendelian randomization (MR).

MATERIALS AND METHODS

Summary data from genome-wide association studies (GWAS) meta-analyses, including gut microbiota GWAS data from 24 cohorts, and the latest GWAS data for hypertension-related conditions were acquired. Employing various MR methods, including Inverse-variance weighted (IVW), MR-Egger, Weighted Median, Simple Mode, and Weighted Mode, we investigated the association between gut microbiota and hypertension-related conditions. Sensitivity analyses were conducted for result stability, and reverse MR analysis assessed the potential for reverse causality.

RESULTS

The Mendelian randomization analysis involving 199 microbial taxa and four phenotypes identified 46 microbial taxa with potential causal links to hypertension and its complications. Following Bonferroni correction, genus.Victivallis showed a robust causal relationship with hypertension (OR = 1.08, 95% CI = 1.04-1.12, P = 9.82e-5). This suggests an 8% increased risk of hypertension with each unit rise in genus.Victivallis abundance.

CONCLUSION

In conclusion, this study establishes a causal connection between gut microbiota and hypertension, along with common associated complications. The findings unveil potential targets and evidence for future hypertension and complication treatment through gut microbiota interventions, offering a novel avenue for therapeutic exploration.

Exploring Therapeutic Targets for Age-Related Macular Degeneration From Circulating Proteins to Plasma Metabolites in the European Population

Purpose

To explore the causal associations among circulating proteins, plasma metabolites, and age-related macular degeneration (AMD).

Methods

We employed Mendelian randomization (MR) analysis and colocalization analysis to discern the causal relationship between proteomes and AMD. This investigation utilized data from protein quantitative trait loci (pQTL) studies in deCODE and the UK Biobank. Additionally, plasma metabolite-related genome-wide association studies (GWAS) data and AMD-related GWAS data were incorporated.

Results

Our findings confirmed a potential causal relationship between cytoplasmic tryptophanyl-tRNA synthetase 1 (WARS1) and a higher risk of AMD. The observed causal impact of WARS1 on the two subtypes of AMD (dry and wet) align consistently with the aforementioned outcomes. Three plasma metabolites-N-acetyl-kynurenine, N-acetyltyrosine, and caproate (6:0)-were identified as mediators of the causal effect of WARS1 on AMD, and subgroup analysis revealed that N-acetyltyrosine is a specific negative metabolite associated with WARS1 and dry AMD, whereas X-16580 is a specific positive metabolite linked to WARS1 and wet AMD.

Conclusions

The outcomes of this study suggest a potential causal role of specific circulating proteins in AMD and identified the mediating role of plasma metabolites between WARS1 and AMD by integrating multiple genetic analyses. Nevertheless, further research is essential to validate and strengthen these conclusions.

Translational Relevance

This study establishes the causal role of specific circulating proteins in AMD and identified the mediating role of plasma metabolites between WARS1 and AMD.

Biological pathways underlying the relationship between childhood maltreatment and Multimorbidity: A two-step, multivariable Mendelian randomisation study

Childhood maltreatment has been associated with multimorbidity of depression, coronary artery disease and type 2 diabetes. However, the biological mechanisms underlying this association remain unclear. We employed two-step and multivariable Mendelian randomisation (MR) to understand the role of three potential biological mediating mechanisms - inflammation (92 proteins), metabolic processes (54 markers), and cortisol - in the link between childhood maltreatment liability and multimorbidity. Using summary statistics from large-scale genome-wide association studies of European ancestry for childhood maltreatment (N = 185,414) and multimorbidity (Neffective = 156,717), we tested for the presence of an indirect effect via each mediator individually. We found a potential role of metabolic pathways. Up to 11% of the effect of childhood maltreatment on multimorbidity was mediated by triglycerides (indirect effect [95% CI]: 0.018 [0.009-0.027]), 8% by glycated haemoglobin (indirect effect: 0.013 [0.003-0.023]), and up to 7% by high-density lipoprotein cholesterol (indirect effect: 0.011 [0.005-0.017]). We did not find evidence for mediation via any inflammatory protein or cortisol. Our findings shed light on the biological mechanisms linking childhood maltreatment liability to multimorbidity, highlighting the role of metabolic pathways. Future studies may explore underlying pathways via non-biological mediators (e.g., lifestyle factors) or via multiple mediators simultaneously.

Getting Up in the Morning and Chronotype in Relation to Polycystic Ovarian Syndrome: A Mendelian Randomization and Cross-Sectional Study

Background

Although a connection between circadian rhythm and polycystic ovarian syndrome (PCOS) has been shown in previous studies, the exact cause of this association is not well understood.

Purpose

This study aimed to use Mendelian randomization (MR) method to analyze the potential association between getting up in the morning and chronotype with PCOS, and a cross-sectional study was conducted to further validate these results.

Methods

Using summary information from large-scale genome-wide association studies (GWASs) in people of European ancestry, we conducted univariable MR (UVMR) and multivariable MR (MVMR) analyses to examine the causal effect of genetically determined getting up in the morning and chronotype on PCOS. We also investigated the association between wake-up time and sleep midpoint with the risk of PCOS and total testosterone (TT) levels in a cohort of 777 women of reproductive age.

Results

Our findings indicate a causal relationship between the genetic prediction of getting up in the morning and chronotype with a reduced incidence of PCOS. In a cross-sectional study, a sleep midpoint of > 4:00 was linked to a higher risk of PCOS and increased TT levels than a sleep midpoint of < 3:30. In women with a BMI < 24 kg/m2, earlier wake-up times and sleep midpoints were associated with a lower risk of PCOS and decreased TT levels.

Conclusion

This study indicates that a genetic predisposition to getting up in the morning and chronotype are linked to a reduced risk of PCOS. Additionally, earlier wake-up times and sleep midpoints are associated with a lower risk of PCOS and decreased TT levels.

Causal effects of depression on prostatitis: a two-step Mendelian randomisation study with immune cell mediation

BACKGROUND

Depression has a significant global impact. Previous studies have suggested a link between depression and prostate diseases. However, these studies are often observational and may be influenced by confounding factors and reverse causality. This research aimed to explore the potential causal relationship between depression and prostate diseases using Mendelian randomisation (MR) and to assess the mediating role of immune cell phenotypes.

METHODS

We utilised MR methods with genome-wide association studies (GWAS) data. The analysis was conducted in two phases: (a) a two-sample MR to investigate the impact of depression on prostate diseases; and (b) a two-step MR to evaluate the mediating effect of 731 immune cell phenotypes. Depression data were obtained from an extensive GWAS involving 480 359 participants across multiple European cohorts. Prostate disease data, including prostatitis, prostate cancer, and benign prostatic hyperplasia, were obtained from European-based GWAS. Independent single nucleotide polymorphisms related to depression were selected based on genome-wide significance criteria. Various MR methods, including inverse variance weighting, weighted median, MR-Egger, MR-PRESSO, MR-Robust, and MR-RAPS, were employed to ensure robust causal inference.

RESULTS

The MR analysis revealed a potential causal relationship between depression and an increased risk of prostatitis (odds ratio = 1.606, P = 8.35E-04). Sensitivity analysis confirmed the robustness of these findings. Additionally, a two-step MR analysis identified CD24+ CD27+ %lymphocytes as a potential mediator, with a mediation effect of 0.108 (P = 0.03), accounting for 22.78% of the total effect.

CONCLUSIONS

This study offers novel genetic evidence for the causal relationship between depression and prostatitis, with immune cells identified as potential mediators in this process. These findings highlight the importance of psychological factors in developing prostatitis and suggest that immune cells could be novel therapeutic targets.

Uromodulin and Risk of Upper Urinary Tract Infections: A Mendelian Randomization Study

RATIONALE & OBJECTIVE

Observational studies suggest that uromodulin, produced by the kidneys, is associated with a reduced risk of upper urinary tract infections (UTIs), but inferences are limited by potential confounding factors. This study sought to explore further the validity of this association using Mendelian randomization (MR).

STUDY DESIGN

Two-sample MR study.

SETTING & PARTICIPANTS

The study included 29,315 and 13,956 participants from 18 cohorts of mainly European ancestry with measured urinary and serum uromodulin levels, respectively, and 3,873 and 512,608 participants from the UK Biobank, the Trøndelag Health Study, or the Michigan Genomic Initiative with and without upper UTIs.

EXPOSURES

We identified uncorrelated (r2 < 0.01) single nucleotide variations that were strongly associated (P < 5 × 10-6) with urinary and serum uromodulin levels from the aforementioned two genome-wide association studies. Both studies accounted for kidney function.

OUTCOMES

Genetic associations for the risk of upper UTIs extracted from the aforementioned independent genome-wide association study.

ANALYTICAL APPROACH

Inverse variance-weighted and sensitivity analyses were performed. The strength of each genetic instrument was estimated using the F statistic.

RESULTS

A 1-standard deviation increase in genetically predicted urinary uromodulin level was associated with an odds ratio (OR) for upper UTIs of 0.80 (95% CI, 0.67-0.95; P = 0.01). A 1-standard deviation increase in serum uromodulin was not statistically associated with elevated odds of upper UTIs, OR = 0.95 (95% CI, 0.89-1.01; P = 0.12). These findings were consistent across the sensitivity analyses.

LIMITATIONS

Analyses could be performed on only participants of predominantly European ancestry, potentially decreasing the generalizability of our findings.

CONCLUSIONS

This two-sample MR study found that increased levels of genetically predicted urinary uromodulin were associated with a reduced risk of upper UTIs. These findings support the hypothesis that uromodulin may have a protective role against upper UTIs.

PLAIN-LANGUAGE SUMMARY

Traditional studies have suggested that uromodulin, a protein produced by the kidneys, may reduce the risk of urinary tract infections (UTIs). The certainty of these findings is limited by the potential influence of unmeasured confounding factors. Therefore, we decided to address this concern by using genetic data to perform a two-sample Mendelian randomization analysis, a technique known to limit the influence of such factors. Our findings support the hypothesis that uromodulin in urine may have a protective role against upper UTIs. The findings were consistent across sensitivity and sex-specific analyses. Further research into the implications of these findings for the treatment of UTIs as well as the possible utility of urinary uromodulin as a diagnostic marker is warranted.

Association Between Inflammatory Cytokines and Refractive Errors: A Bidirectional Mendelian Randomization Study

Purpose

This investigation aimed to elucidate the causal role of inflammatory cytokines in the risk of developing refractive errors.

Methods

Genetic variants previously associated with inflammatory cytokines served as instrumental variables in genome-wide association studies (GWASs) of European ancestry. Bidirectional two-sample Mendelian randomization (MR) analyses were conducted using summary data from GWAS meta-analyses. Rigorous sensitivity analyses were performed to validate the reliability of the MR results.

Results

We found that, for every unit increase in interleukin 1 receptor antagonist (IL1RA) and interleukin 2 (IL2), there was a corresponding decrease in the prevalence of myopic refractive errors by 0.235 (95% confidence interval [CI], 0.050-0.419 for fixed effects; 95% CI, 0.125-0.345 for random effects) and 0.132 (95% CI, 0.032-0.231 for fixed effects; 95% CI, 0.044-0.220 for random effects), respectively. No substantial causal associations were observed for IL1α, IL1β, IL12p70, or monocyte chemoattractant protein 1 (MCP1) with refractive errors. Conversely, reverse MR analyses failed to indicate a causal influence of refractive errors on IL1RA and IL2.

Conclusions

The present study offers evidence for a causal link between inflammatory cytokines and refractive errors, which could have significant implications for the early detection, surveillance, and management of refractive errors.

Translational Relevance

Our study underscores the importance of IL1RA and IL2 in the prevention and management of refractive errors, suggesting the feasibility of strategies for early identification, continuous surveillance, and the deployment of focused therapeutic approaches.

Association between Plasma Metabolite Levels and Myopia: A 2-Sample Mendelian Randomization Study

Purpose

The role of plasma metabolites in myopia is still unclear, and previous studies are limited by various factors and were mostly observational. This study aims to investigate the causal relationship between plasma metabolites and myopia using 2-sample Mendelian randomization (MR).

Design

A 2-sample MR study.

Subjects and Participants

This study analyzed plasma metabolites consisting of 1091 metabolites and 309 metabolite ratios in 8299 individuals from the Canadian Longitudinal Study on Aging cohort. Summary statistics for myopia were obtained from the UK Biobank, encompassing 37 362 cases and 460 536 controls.

Methods

Causal effect estimates were primarily derived using the inverse variance weighting (IVW) method and the constrained maximum likelihood and model averaging-based MR method. Statistical significance for the MR effect estimate was defined as a false discovery rate (FDR) of <0.05. Additionally, we used the MR Steiger directionality test to examine whether exposure was directionally causal for the outcome. Furthermore, 4 supplementary methods were used for analysis: weighted median, MR-Egger, simple mode, and weighted mode.

Main Outcome Measures

Genetic causal association between plasma metabolites and myopia.

Results

The IVW analysis results indicated that elevated levels of 1-arachidonoyl-GPE (20:4n6) (P_FDR = 5.80E-06), linoleoyl-arachidonoyl glycerol (18:2/20:4)[1] (P_FDR = 2.24E-06), and linoleoyl-arachidonoyl-glycerol (18:2/20:4) [2](P_FDR = 0.0242) have a protective effect on myopia. Elevated levels of 4 plasma metabolite ratios, including the phosphate to linoleoyl-arachidonoyl-glycerol (18:2/20:4) [2] ratio (P_FDR = 0.0029), citrulline to dimethylarginine (SDMA + ADMA) ratio (P_FDR = 0.0207), oleoyl-linoleoyl-glycerol (18:1/18:2) [2] to linoleoyl-arachidonoyl-glycerol (18:2/20:4) [1] ratio (P_FDR = 0.0230), and retinol (vitamin A) to linoleoyl-arachidonoyl-glycerol (18:2/20:4) [2] ratio (P_FDR = 0.0230), were significantly associated with a higher risk of myopia.

Conclusions

This study provides evidence of a causal relationship between specific plasma metabolites and myopia, highlighting potential therapeutic targets and contributing to the understanding of myopia's etiology. Future research should include diverse populations to enhance the generalizability of these findings.

Financial Disclosures

The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Genetic Evidence Supporting a Causal Association Between mTORC1-Dependent Circulating Protein Levels and Diabetic Retinopathy

Purpose

The mechanistic target of rapamycin (mTOR) signaling pathway is essential for the onset and progression of diabetic retinopathy (DR). Nevertheless, the impact of mTORC1 downstream proteins in DR remains uncertain. Therefore, we performed a Mendelian randomization (MR) research to assess the causal effect of downstream mTORC1 proteins on DR risk.

Methods

Summary statistics on mTORC1 downstream proteins and DR were obtained from the INTERVAL and FinnGen studies (14,584 patients and 176,010 controls), respectively. We used various MR techniques, including inverse-variance-weighted, weighted median, and MR-Egger. Possible pleiotropy and heterogeneity were identified through sensitivity analysis.

Results

Genetically predicted eIF4E was positively correlated to DR risk (odds ratio = 1.057; 95% confidence interval, 1.008-1.109; P = 0.022]. No relationship has been shown for circulating RP-S6K, eIF4G, eIF4A, eIF4E-BP and eIF4B levels with DR formation. There was no heterogeneity or unbalanced level pleiotropy identified.

Conclusions

Higher levels of serum eIF4E promote the progression of DR, proposing that pharmacological inhibition of eIF4E activity may be a prospective DR therapeutic strategy.

Translational Relevance

The present study has highlighted the role of eIF4E in the development of DR, establishing the foundation for basic research into DR targets.

Association of Breast Cancer and Selective Estrogen Receptor Modulators on the Risk of Meningioma: Insights from Mendelian Randomization

Considering the potential links between breast cancer (BC), selective estrogen receptor modulators, and meningioma in previous epidemiology studies, this study aimed to investigate them through the Mendelian randomization approach. We extracted instrumental variables (IVs) of different subtypes of BC from the largest genome-wide association study. Gene targets of SERMs were obtained from the Drug-Gene Interaction Database. Mendelian randomization (MR) analysis applied inverse variance weighted approach to evaluate causality. A series of sensitivity analyses and reverse MR were used to evaluate the stability of the MR results. Genetically determined estrogen receptor (ER) positive BC, luminal A-like breast cancer (OR 1.17, 95% CI 1.04 to 1.32, p = 0.01), and luminal B-like breast cancer (OR 1.20, 95% CI 1.04 to 1.37, p = 0.009) were associated with an increased odds ratio of meningioma (OR 1.18, 95% CI 1.05 to 1.32, p = 0.005). Among SERM-targeted genes, CYP2D6 (OR 1.37, 95% CI 1.23 to 1.54, p = 4.15 × 10- 8), NGR1 (OR 1.15, 95% CI 1.10 to 1.20, p = 2.59 × 10- 11), and MAPT (OR 10.20, 95% CI 2.90 to 35.84, p = 0.0003) were associated with increased meningioma risk, while BRCA1 (OR 0.67, 95% CI 0.57 to 0.80, p = 4.88 × 10- 6) showed negative causal association with meningioma risk. The outcome of the sensitivity analysis and reverse MR analysis corroborated the findings. These findings suggested a causal relationship between BC and meningioma, and identified potential target genes associated with meningioma, which was beneficial to early identification and prevention of meningioma risk.

Mitochondrial DNA Copy Number as a Hidden Player in the Progression of Multiple Sclerosis: A Bidirectional Two-Sample Mendelian Randomization Study

The relationship between mitochondrial DNA copy number (mtDNA-CN) and multiple sclerosis (MS) progression remains unclear, as previous observational studies have reported conflicting results. This study aimed to clarify the association between mtDNA-CN and MS progression using a bidirectional two-sample Mendelian randomization (MR) approach. MR analyses were conducted using the latest summary statistics from genome-wide association studies (GWAS) on mtDNA-CN and MS progression. Single-nucleotide polymorphisms (SNPs) associated with mtDNA-CN were extracted from 383,476 participants of European ancestry in the UK Biobank, while SNPs associated with MS severity were obtained from the International Multiple Sclerosis Genetics Consortium (IMSGC), comprising 12,584 cases of European ancestry. The inverse variance weighted (IVW) method was used as the primary analysis. Potential heterogeneity and pleiotropy were evaluated, and sensitivity analyses were performed to ensure the robustness of the results. The forward MR analysis using the IVW method revealed no significant association between mtDNA-CN and MS progression (P = 0.487). However, reverse MR analysis identified a causal association between MS progression and mtDNA-CN (β =  - 0.010, 95% CI =  - 0.019 to - 0.001, P = 0.036). No evidence of heterogeneity or horizontal pleiotropy was found in the analyses. Sensitivity analyses yielded consistent results. Our findings suggest that MS progression may causally influence mtDNA-CN, highlighting the crucial role of mitochondria in the pathophysiology of MS. However, further research is needed to confirm mtDNA-CN as a reliable biomarker and a deeper understanding of the molecular mechanisms is necessary to develop targeted therapeutic interventions.

Evaluating the Causal Association Between Type 2 Diabetes and Alzheimer's Disease: A Two-Sample Mendelian Randomization Study

Background/Objectives: Type 2 diabetes mellitus (T2DM) and Alzheimer's disease (AD) are significant global health issues. Epidemiological studies suggest T2DM increases AD risk, though confounding factors and reverse causality complicate this association. This study aims to clarify the causal relationship between T2DM and AD through a systematic review and meta-analysis of Mendelian randomization (MR) studies and a new two-sample MR analysis. Methods: A literature search across major databases was conducted through May 2024 to identify MR studies linking T2DM and AD. Fixed/random-effect models provided pooled odds ratios (ORs) with 95% confidence intervals (CIs), and heterogeneity was assessed with the I2 statistic. For our MR analysis, we pooled genetic variants from selected studies and analyzed AD outcomes using IGAP, EADB, and UKB databases. Multiple MR methods, including inverse variance weighted (IVW) and pleiotropy-robust approaches, were applied for validation. Results: Of 271 articles, 8 MR studies were included (sample sizes: 68,905 to 788,989), all from European ancestry. Our meta-analysis found no significant causal link between T2DM and AD (OR = 1.02, 95% CI: 1.00-1.04) with moderate heterogeneity (I2 = 31.3%). Similarly, our MR analysis using 512 SNPs as instrumental variables showed no significant associations in IGAP, EADB, or UKB data, which is consistent across sensitivity analyses. Conclusions: This meta-MR and MR analysis revealed no significant causal association between T2DM and AD, indicating that genetic predisposition to T2DM does not appear to causally influence AD risk, though modifiable clinical or environmental aspects of T2DM may still contribute to neurodegenerative processes. Further research should explore other mechanisms linking these conditions.

Blood Pressure Lowering and Risk of Cancer: Individual Participant-Level Data Meta-Analysis and Mendelian Randomization Studies

BACKGROUND

Pharmacologic blood pressure (BP) lowering is typically a lifelong treatment, and both clinicians and patients may have concerns about the long-term use of antihypertensive agents and the risk for cancer. However, evidence from randomized controlled trials (RCTs) regarding the effect of long-term pharmacologic BP lowering on the risk for new-onset cancer is limited, with most knowledge derived from observational studies.

OBJECTIVES

The aim of this study was to assess whether long-term BP lowering affects the risk for new-onset cancer, cause-specific cancer death, and selected site-specific cancers.

METHODS

Individual-level data from 42 RCTs were pooled using a one-stage individual participant data meta-analysis. The primary outcome was incident cancer of all types, and secondary outcomes were cause-specific cancer death and selected site-specific cancers. Prespecified subgroup analyses were conducted to assess the heterogeneity of the BP-lowering effect by baseline variables and over follow-up time. Cox proportional hazards regression, stratified by trial, was used for the statistical analysis. For site-specific cancers, analyses were complemented with Mendelian randomization, using naturally randomized genetic variants associated with BP lowering to mimic the design of a long-term RCT.

RESULTS

Data from 314,016 randomly allocated participants without known cancer at baseline were analyzed. Over a median follow-up of 4 years (Q1-Q3: 3-5 years), 17,954 participants (5.7%) developed cancer, and 4,878 (1.5%) died of cancer. In the individual participant data meta-analysis, no associations were found between reductions in systolic or diastolic BP and cancer risk (HR per 5 mm Hg reduction in systolic BP: 1.03 [95% CI: 0.99-1.06]; HR per 3 mm Hg reduction in diastolic BP: 1.03 [95% CI: 0.98-1.07]). No changes in relative risk for incident cancer were observed over follow-up time, nor was there evidence of heterogeneity in treatment effects across baseline subgroups. No effect on cause-specific cancer death was found. For site-specific cancers, no evidence of an effect was observed, except a possible link with lung cancer risk (HR for systolic BP reduction: 1.17; 99.5% CI: 1.02-1.32). Mendelian randomization studies showed no association between systolic or diastolic BP reduction and site-specific cancers, including overall lung cancer and its subtypes.

CONCLUSIONS

Randomized data analysis provided no evidence to indicate that pharmacologic BP lowering has a substantial impact, either increasing or decreasing, on the risk for incident cancer, cause-specific cancer death, or selected site-specific cancers.

Association of Ischemic Stroke with Zoster Risk: A Mendelian Randomized Study

BACKGROUND

Recent observational investigations suggest a likely correlation between stroke lacking a blood supply-cerebral arterial thrombosis (ischemic stroke) and herpes zoster (HZ), although the causality remains unclear. This study aims to explore the potential causal link in relation to ischemic stroke and HZ. We performed a Mendelian randomization analysis (MR). Our objective is to provide fresh perspectives for the clinical prevention of ischemic stroke in individuals with HZ.

METHODS

Data from the European Molecular Biology Laboratory were utilized in the genome-wide association study (GWAS) of ischemic stroke. The study included data from 484,121 participants, with the FinnGen Consortium contributing data for zoster outcomes (n_case = 2080; n_control = 211,856), primarily focusing on European population samples. We conducted a comparative analysis of figures from the GWAS for ischemic stroke alongside that for zoster within a MR framework. Employing inverse variance weighting as our primary method of analysis, we undertook a thorough investigation into the potential causal relationship between ischemic stroke and zoster. Additionally, we adopted complementary approaches, including maximum likelihood estimation, MR-Egger, weighted median, and MR-Polyvalent Residuals and Outliers method to provide a comprehensive assessment of causality. To examine the variability among the instrumental variables, we utilized Cochran's Q statistic as a key indicator.

RESULTS

The analysis weighted by inverse variance indicated a significant impact of ischemic stroke on zoster within the zoster GWAS databases, yielding an odds ratio (OR) of 1.463 (95% confidence interval [CI]: 1.001-2.138; P value = 0.04). However, the MR-Egger analysis failed to yield substantial evidence for this relationship, presenting an OR of 0.599 (95% CI: 0.129-2.773; P value = 0.52).Similarly, the weighted median analysis failed to offer compelling endorsement of the association between ischemic stroke and zoster incidence, reporting an OR of 1.15 (95% CI: 0.736-1.806; P = 0.53).

CONCLUSIONS

The implications of the MR analysis demonstrate a causal linkage between ischemic stroke and zoster.

Genetic approach uncovering the pathways between childhood maltreatment and suicide attempt

Childhood maltreatment significantly heightens the risk of suicide attempt, but the causal mechanisms and underlying pathways are not fully understood. Using genetic instruments for both childhood maltreatment (n = 185,414) and suicide attempt (cases = 29,782; controls = 519,961), we performed two-sample Mendelian randomization analyses. Our results show that higher level of childhood maltreatment is causally associated with an increased risk of suicide attempt (OR = 3.40; 95% CI, 2.34-4.96, P = 1.3e-10). We then conducted a two-step Mendelian randomization mediation analysis, identifying 11 out of 58 potential mediators between childhood maltreatment and suicide attempt. These mediators included neurobiological, psychopathological and behavioral factors. The psychopathological factors had the most significant impact, accounting for 10.4-50.2% the mediation. This study confirms the causal relationship between childhood maltreatment and suicide attempt, highlighting specific mediators-especially within the psychopathological dimension-that can guide targeted interventions to alleviate the adverse effects of childhood maltreatment and prevent suicide attempt.

Causal effect of gut microbiota on the risk of cancer and potential mediation by inflammatory proteins

BACKGROUND

While growing evidence highlights the role of gut microbiota and inflammatory proteins in cancer, with cancer-related inflammation now considered the seventh hallmark of cancer, the direct causal relationships between specific microbiota, cancer, and the potential mediating effects of inflammatory proteins have not been fully established.

METHODS

We employed Mendelian randomization (MR) to assess the causal relationships between gut microbiota, inflammatory proteins, and eighteen distinct cancers using data from extensive genome-wide association studies (GWAS). The primary statistical method utilized was inverse variance weighting (IVW). We also investigated whether inflammatory proteins could mediate the effects of gut microbiota on cancer development.

RESULTS

Our findings revealed 42 positive and 49 inverse causal impacts of gut microbiota on cancer risk (P < 0.05). Additionally, we identified 32 positive and 28 inverse causal relationships between inflammatory proteins and cancer risk. Moreover, genus Collinsella decreased the risk of lung cancer by decreasing levels of T-cell surface glycoprotein CD5 (mediating effect = 16.667%), while genus Ruminococcaceae UCG005 increased the risk of mesothelioma by increasing levels of CCL4 (mediating effect = 5.134%).

CONCLUSIONS

Our study provides evidence for a causal association between gut microbiota, inflammatory proteins, and eighteen different cancer types. Notably, the T-cell surface glycoprotein CD5 and CCL4 were identified as mediators linking the genus Collinsella with lung cancer and the genus Ruminococcaceae UCG005 with mesothelioma, respectively.

Evidence supporting the role of hypertension in the onset of migraine

BACKGROUND

The association between hypertension and migraine remains unclear.

OBJECTIVE

The aim of this study employ multi-layered evidence chain that revealed the association between hypertension and migraine.

METHODS

We first strictly included data from the NHANES 1999-2004 population and applied logistic regression, subgroup analysis and RCS to assess the correlation between hypertension, SBP, DBP and migraine. Meanwhile, LDSC and Mendelian randomization were conducted based on the GWAS to determine the causal relationship between hypertension and migraine. Inverse-variance weighted (IVW) was used as the primary method. Sensitivity analysis and Colocalization analysis were performed to confirm the robustness of the results. LDSC validated the genetic correlation between traits. Enrichment analysis revealed their underlying biological mechanisms.

RESULTS

After strict inclusion in NHANES, 10,743 participants were included. The logistic regression showed a significant correlation between hypertension (OR = 1.21 [95% CI, 1.08-1.36], FDR < 0.001)、DBP (OR = 1.01 [95% CI, 1.01-1.02], FDR < 0.001) and migraine. This association did not show significant group differences in subgroup. The MR results further supported the existence of a significant causal relationship between hypertension (OR = 1.77 [95% CI, 1.43-2.30], FDR < 0.001)、DBP (OR = 1.02 [95% CI, 1.01-1.03], FDR < 0.001) and migraine onset. Additionally, the RCS analysis showed a linear relationship (P non-linear = 0.897) between the two. The LDSC result showed a significant genetic correlation between the two (Rg = 0.1092, SE = 0.028, P < 0.001).

CONCLUSION

The development of migraine caused by hypertension is mainly realized through high DBP.

Allantoin Serves as a Novel Risk Factor for the Progression of MASLD

Uric acid (UA), traditionally recognized as an extracellular antioxidant, exhibits paradoxical associations with metabolic disorders such as metabolic dysfunction-associated steatotic liver disease (MASLD), though its mechanistic contributions remain elusive. Here, we integrate multi-modal evidence to explore the role of UA and its oxidative metabolite, allantoin, in MASLD progression. Analysis of UK Biobank data revealed a strong association between elevated UA levels and increased risks of MASLD and type 2 diabetes (T2D). However, Mendelian randomization analysis of over 2 million samples demonstrated causal effects of urate solely on serum triglycerides and T2D risk. Targeted metabolomics in an elderly Chinese cohort identified allantoin, an oxidative by-product of UA, significantly elevated in individuals with dyslipidemia or T2D, with serum allantoin levels positively correlated with fasting glucose, triglycerides, and cholesterol. Animal studies indicated that allantoin exacerbates hepatic lipid accumulation and glucose intolerance in high-fat diet mice, driven by increased hepatic lipid biogenesis and reduced bile acid production. Notably, further research revealed a strong binding affinity of allantoin for PPARα, leading to the suppression of PPARα activity, which promotes the progression of MASLD. These findings underscore the critical role of allantoin, rather than UA, as a critical driver of MASLD development, offering valuable insights for the prediction and management of hepatic metabolic disorders.

A Multi-omics approach to identify and validate shared genetic architecture in rheumatoid arthritis, multiple sclerosis, and type 1 diabetes: integrating GWAS, GEO, MSigDB, and scRNA-seq data

The notable comorbidity among autoimmune diseases underscores their shared genetic underpinnings, particularly evident in rheumatoid arthritis (RA), type 1 diabetes (T1D), and multiple sclerosis (MS). However, the exact components and mechanisms of this shared genetic structure remain poorly understood. Here we show that ROMO1 is a key shared genetic component among RA, MS, and T1D. Using differential gene expression (DGE) and LASSO regression analyses of bulk RNA-seq data from whole blood tissues, we identified ROMO1 as a potential shared genetic factor. A multi-sample analysis with external Gene Expression Omnibus (GEO) data revealed ROMO1's consistent association with immune cell patterns across tissues in all three diseases. Single-gene Gene Set Enrichment Analysis (GSEA) suggested ROMO1's involvement in the reactive oxygen species (ROS) pathway, which was further substantiated by conjoint analysis with 256 ROS pathway-related genes(ROSGs) from Molecular Signatures Database (MSigDB). Single-gene Receiver Operating Characteristic (ROC) analysis highlighted ROMO1's potential as a disease biomarker. Single-cell RNA sequencing (scRNA-seq) analysis showed significantly altered ROMO1 expression in monocytes and other immune cells compared to healthy control (HC). Immune infiltration analysis revealed ROMO1's significant association with monocytes across all three diseases. Furthermore, two-sample Mendelian randomization (MR) analysis using genome-wide association studies (GWAS) data demonstrated that ROMO1 could regulate epitopes on monocytes, potentially lowering autoimmune disease risk. Our findings clarify the importance of ROMO1 in the shared genetic architecture of RA, MS, and T1D, and its underlying mechanism in disease development.

A network pharmacological target mendelian randomization study on the neuroprotective effects of active ingredients in mahuang fuzi xixin decoction for multiple sclerosis

Mahuang Fuzi Xixin Decoction (MFX), a traditional Chinese medicine containing 44 volatile components (97.36% total oil), includes key compounds like α-terpenol (13.34%) and 1,2,3-trimethoxy-5-methyl-benzene (22.64%). Using network pharmacology and Mendelian randomization, 24 active compounds were identified targeting MS-related pathways (NF-κB, NLRP3, Toll-like receptor). Genetic variants in CYP450, GSK3B, CYBB, and PON1 correlated with reduced MS risk. In EAE mice, MFX decreased spinal GSK-3B expression (immunofluorescence) and pro-inflammatory factors (ELISA), demonstrating neuroprotection via anti-inflammatory, antioxidative mechanisms and restored GSK-3B levels, highlighting therapeutic potential for MS.

Cardiovascular diseases and depression: A meta-analysis and Mendelian randomization analysis

Depression is a common psychiatric symptom among patients with cardiovascular disease (CVD), adversely affecting their health. Despite the identification of various contributing factors, the precise mechanisms linking CVD and depression remain elusive. This study conducted a meta-analysis to investigate the association between CVD and depression. Furthermore, a bidirectional Mendelian randomization (MR) analysis was undertaken to clarify the causal relationship between the two conditions. The meta-analysis included 39 studies, encompassing 63,444 patients with CVD, 12,308 of whom were diagnosed with depression. The results revealed a significant association between CVD and depression or anxiety, with an estimated overall prevalence of depression in CVD patients of 20.8%. Subgroup analyses showed that the prevalence of depression in patients with coronary artery disease and heart failure was 19.8% and 24.7%, respectively. According to a random-effects model, depressive symptoms were linked to an increase in unadjusted all-cause mortality compared with non-depressed patients. The MR analysis, employing the inverse-variance weighted method as the primary tool for causality assessment, identified significant associations between various CVD types and depression or anxiety phenotypes. These findings underscore the significant relationship between CVD and depression or anxiety, leading to an elevated risk of all-cause mortality. Moreover, the MR analysis provides the first genetically-informed evidence suggesting that depression plays a critical role in the development and progression of certain CVD subtypes. This emphasizes the need for addressing depressive symptoms in CVD patients to prevent or reduce adverse cardiovascular outcomes.

Transcriptome-wide Mendelian randomisation exploring dynamic CD4+ T cell gene expression in colorectal cancer development

Background

Recent research has identified a potential protective effect of higher numbers of circulating lymphocytes on colorectal cancer (CRC) development. However, the importance of different lymphocyte subtypes and activation states in CRC development and the biological pathways driving this relationship remain poorly understood and warrant further investigation. Specifically, CD4+ T cells - a highly dynamic lymphocyte subtype - undergo remodelling upon activation to induce the expression of genes critical for their effector function. Previous studies investigating their role in CRC risk have used bulk tissue, limiting our current understanding of the role of these cells to static, non-dynamic relationships only.

Methods

Here, we combined two genetic epidemiological methods - Mendelian randomisation (MR) and genetic colocalisation - to evaluate evidence for causal relationships of gene expression on CRC risk across multiple CD4+ T cell subtypes and activation stage. Genetic proxies were obtained from single-cell transcriptomic data, allowing us to investigate the causal effect of expression of 1,805 genes across five CD4+ T cell activation states on CRC risk (78,473 cases; 107,143 controls). We repeated analyses stratified by CRC anatomical subsites and sex, and performed a sensitivity analysis to evaluate whether the observed effect estimates were likely to be CD4+ T cell-specific.

Results

We identified six genes with evidence (FDR-P<0.05 in MR analyses and H4>0.8 in genetic colocalisation analyses) for a causal role of CD4+ T cell expression in CRC development - FADS2, FHL3, HLA-DRB1, HLA-DRB5, RPL28, and TMEM258. We observed differences in causal estimates of gene expression on CRC risk across different CD4+ T cell subtypes and activation timepoints, as well as CRC anatomical subsites and sex. However, our sensitivity analysis revealed that the genetic proxies used to instrument gene expression in CD4+ T cells also act as eQTLs in other tissues, highlighting the challenges of using genetic proxies to instrument tissue-specific expression changes.

Conclusions

Our study demonstrates the importance of capturing the dynamic nature of CD4+ T cells in understanding disease risk, and prioritises genes for further investigation in cancer prevention research.