Inverse-variance Weighted Method Research Articles

Genetically Predicted Iron Status Is a Causal Risk of Rheumatoid Arthritis: A Mendelian Randomization Study.

Background Current knowledge on iron's role in rheumatoid arthritis (RA) development is very limited, with studies yielding inconsistent findings. We conducted a two-sample Mendelian randomization study to assess the associations of iron status with the risk of RA. Methods This study leveraged genetic data from a large genome-wide association study (GWAS) of 257,953 individuals to identify single nucleotide polymorphisms (SNPs) associated with iron status. We then analyzed these data in conjunction with summary-level data on RA from the IEU open GWAS project, which included 5,427 RA cases and 479,171 controls. An inverse-variance weighted method with random effects was employed, along with sensitivity analyses, to assess the relationship between iron status and RA risk. Results Genetic predisposition to high ferritin and serum iron status was causally associated with lower odds of RA. Ferritin had an odds ratio (OR) of 0.997 (95% confidence interval [CI]: 0.995-0.997; p = 0.010), indicating that a one-unit increase in ferritin is associated with a 0.3% decrease in the odds of RA. Similarly, serum iron had an OR of 0.997 (95% CI: 0.995-0.999; p = 0.014). However, MR analyses found no significant causal associations between total iron-binding capacity (OR = 1.0, 95% CI: 0.999-1.002; p = 0.592) or transferrin saturation percentage (OR = 0.998, 95% CI: 0.996-1.000; p = 0.080) and risk of developing RA. Conclusions This study suggests that individuals with genes linked to higher iron levels may have a lower risk of developing RA. Our findings indicate that the total amount of iron in the body, rather than how it is distributed, might be more important for RA. This raises the intriguing possibility that iron supplementation could be a preventative strategy, but further research is necessary.

Cerebrospinal fluid metabolites as potential biomarkers for epilepsy: Insights from genome‐wide association studies

AbstractObjectivesWhile metabolic imbalances have been observed in individuals with epilepsy, the direct involvement of specific metabolites in the development of the condition remains underexplored. A comprehensive analysis of the causality between cerebrospinal fluid metabolites (CSF) and epilepsy is pivotal in discovering innovative therapeutic interventions and prophylactic approaches.MethodsSummary data from genome‐wide association studies (GWAS) of CSF metabolites and epilepsy subtypes were obtained separately. A total of 338 CSF metabolites were investigated as exposures, and 11 epilepsy phenotypes were examined as the outcomes. A two sample Mendelian randomization (MR) approach was utilized to explore the causal influence of these metabolites on epilepsy. Causality was primarily estimated through inverse variance weighted (IVW) analysis, complemented by a range of sensitivity analyses to ensure result stability. Additionally, reverse MR analysis was performed to explore the possibility of bidirectional causality.ResultsThe IVW method, reinforced by sensitivity analyses, pinpointed 17 CSF metabolites with causal implications for six epilepsy phenotypes. After False Discovery Rate (FDR) multiple testing correction, two metabolites (Methylmalonate and Gamma‐glutamyl‐alpha‐lysine) were found to have robust causal links to epilepsy (p < 0.05 and FDR<0.05). The other 15 metabolites exhibited suggestive evidence of a causal association (p < 0.05 and FDR>0.05).SignificanceThis study highlights CSF metabolites that could serve as valuable biomarkers and may be critical in developing targeted treatments and preventing epilepsy.Plain Language SummaryThis study explores how certain chemicals in the brain fluid might influence the development of epilepsy, aiming to find new ways to treat or prevent it. Researchers looked at the relationship between 338 cerebrospinal fluid metabolites and 11 types of epilepsy using genetic data. They found that 17 of these chemicals could potentially cause six types of epilepsy. Two of these chemicals were strongly linked to epilepsy, suggesting they could be important for creating specific treatments or prevention strategies.

Causal relationship between benign prostatic hyperplasia and prostate cancer: a bidirectional Mendelian randomization analysis.

Our aim is to explore the relation between benign prostatic hyperplasia (BPH) and prostate cancer (PCa) from a genetic level utilizing Mendelian randomization (MR). The IEU genome-wide association studies database was surveyed for single nucleotide polymorphisms (SNPs) associated with BPH, PCa, and PCa (validation cohort). Single nucleotide polymorphisms were subjected to stringent quality control based on rigorous screening criteria. BPH and PCa risk were evaluated using the inverse-variance weighted method (IVW), MR-Egger, simple mode, weighted median, and weighted mode. Horizontal pleiotropy of single nucleotide polymorphisms was assessed using the MR-Egger intercept test, while heterogeneity was evaluated using Cochran's Q test. Reverse causality was assessed by evaluating PCa as the exposure and BPH as the outcome. A validation database was used to verify the exposure and outcome. The risk of PCa increased significantly with genetically predicted BPH (IVW: OR [95% CI] = 1.3849 × 107 [2330, 8.2294 × 1010], P = 2.0814 × 10-4). In reverse MR analysis, PCa also increased the risk of BPH (IVW: OR [95% CI] = 1.0011 [1.0003, 1.0019], P = 0.0031). The findings were consistent with the MR analysis results of the PCa validation cohort. Sensitivity analyses indicated the presence of heterogeneity but no horizontal pleiotropy. The study presents proof of a significant bidirectional causal relationship between genetically predicted BPH and an increased risk of PCa. Key message Three research questions and three bullet points What is already known on this topic? Observational studies suggest a controversial relationship between BPH and PCa. MR allows investigation of causality using genetic variants as instrumental variables (IVs). What does this study add? The study presents proof of a significant bidirectional causal relationship between genetically predicted BPH and an increased risk of PCa. How this study might affect research, practice, or policy? Recognizing the bidirectional relationship between BPH and PCa, men diagnosed with BPH may benefit from more stringent PCa screening protocols.

Gut Microbiota’s role in lipoma development: evidence from mendelian randomization

BackgroundLipoma, a benign tumor derived from mesenchymal tissue, significantly affects patients’ physical and psychological wellbeing. Increasing evidence points to a strong link between the gut microbiome (GM) and lipoma incidence. This study utilizes Mendelian Randomization (MR) to assess the potential causal relationships between the GM and lipoma development.MethodsWe conducted a two-sample MR analysis using genome-wide association study (GWAS) data from MiBioGen and FinnGen to explore the causal relationship between GM and lipoma. The GM dataset included 18,340 participants with 14,587 single nucleotide polymorphisms (SNPs), while the lipoma dataset comprised 412,181 participants with 21,306,349 SNPs. We employed 5 MR methods: Inverse Variance Weighted (IVW), Weighted Median, Simple Mode, MR-Egger, and Weighted Mode. Additional assessments included Cochran’s Q test for result heterogeneity, PRESSO analysis for horizontal pleiotropy, and sensitivity analyses through scatter plots, leave-one-out analyses, funnel plots, and forest plots.ResultsThe IVW method identified 18 gene predictors trans-genus associated with lipoma risk. Protective effects against benign lipoma (BL) were observed in the Eubacterium rectale group, Desulfovibrio, Ruminococcus1, Clostridium sensu stricto1, and Lachnospiraceae UCG001; conversely, Lachnospiraceae UCG008 was linked to increased BL risk. Desulfovibrio provided protection against TS-BL; however, the Family XIII AD3011 group, Eubacterium coprostanoligenes group, Lachnospiraceae NK4A136 group, and Parasutterella were associated with an increased TS-BL risk. The Clostridium innocuum group, Eubacterium rectale group, Anaerotruncus, Ruminiclostridium6, and Lachnospiraceae UCG001 offered protection against LS-BL, while Lachnospiraceae UCG008 was linked to an increased LS-BL risk. The Eubacterium brachy group, Odoribacter, Butyricimonas, Subdoligranulum, and Clostridium sensu stricto1 were protective against HFNS-BL; Ruminococcaceae UCG005 was associated with an increased HFNS-BL risk.ConclusionCompared to malignant tumors, research on lipomas has been relatively limited. This study, through MR analysis, provided new evidence of a causal relationship between specific GM and the development of lipomas. Certain gut bacterial species may act as protective or harmful factors in lipoma formation, offering new avenues for future treatment strategies. However, additional research is required to unravel the complexity of how GM influences the pathogenesis of lipomas.

Rheumatoid Arthritis, Circulating Inflammatory Proteins, and Hypertension: A Mendelian Randomization Study.

Observational studies have indicated that there is an association between rheumatoid arthritis (RA) and an elevated risk of hypertension. However, a definitive causal relationship between the two conditions has not been established. The objective of this study was to investigate the causal link between RA and hypertension, as well as the potential mediating role of circulating inflammatory proteins in this relationship. We utilized Mendelian randomization (MR) to examine the causal relationship between RA and hypertension. The study data were obtained from publicly accessible genome-wide association study (GWAS) databases and meta-aggregates of large GWAS studies. The primary statistical method for determining causal effects was the inverse variance weighted (IVW) method, which was supplemented by a variety of sensitivity analyses. The results of the IVW method suggest a causal relationship between RA and an increased risk of hypertension (OR = 1.03, 95% CI = 1.01-1.04, p = 3.32×10-5). This association remained statistically significant even after adjusting for multiple confounding factors. Furthermore, MR analyses also revealed causal links between 10 circulating inflammatory proteins and the risk of hypertension, with TNF-related activation-induced cytokine partially mediating RA-induced hypertension at a mediator ratio of 11.17% (0.27%-22.08%). Our study identifies causal relationships between several genetically determined inflammatory proteins and hypertension, establishing that RA increases hypertension risk, with inflammation partially mediating this effect. These findings provide new evidence supporting the inflammatory hypothesis in the mechanism of hypertension. Inflammatory factors may serve as potential targets for antihypertensive therapy.

Investigating the causal impact of gut microbiota on arthritis via inflammatory proteins using mendelian randomization

Previous studies have suggested a potential association between the gut microbiota and arthritis. However, the causal links between the gut microbiota and various types of arthritis, as well as the potential mediating role of inflammatory proteins, remain unclear. Mendelian randomization was used to explore the causal relationships between gut microbiota, inflammatory proteins, and various forms of arthritis (osteoarthritis, rheumatoid and psoriatic arthritis, and ankylosing spondylitis [AS]). The inverse variance-weighted method was the primary analytical approach used. Furthermore, we examined the mediating role of inflammatory proteins in the pathway linking the gut microbiota to arthritis. Sensitivity analyses were performed to verify the robustness of the findings, and enrichment analyses were conducted to investigate the biological functions and pathways involved. We identified 11 positive and 14 negative causal effects linking the genetic liability of the gut microbiota to arthritis. Similarly, 9 positive and 8 negative causal effects between inflammatory proteins and arthritis were identified. Notably, an increased abundance of the order Bacillales (odds ratio [OR] = 1.199, 95% confidence interval [CI] = 1.030–1.394, P = 0.019) and higher interleukin-7 levels (OR = 1.322, 95% CI = 1.004–1.741, P = 0.046) significantly elevated the risk of AS. Furthermore, interleukin-7 mediated 13.8% of the effect caused by the order Bacillales, with a mediation effect size of β = 0.025 (95% CI = 0.001–0.064). Sensitivity and supplementary analyses revealed no significant evidence of horizontal pleiotropy or heterogeneity. Overall, our findings demonstrate causal links between the gut microbiota, inflammatory proteins, and four arthritis types, highlighting the gut microbiota as a potential therapeutic target. Crucially, interleukin-7 not only strongly correlated with AS but also partially mediated the effect exerted by the gut microbiota on AS, suggesting that managing the gut microbiota to modulate inflammatory proteins could serve as an effective therapeutic strategy for arthritis.

Recurrent aphthous stomatitis and neoplasms of the mouth and pharynx: a two-sample Mendelian randomization study

BackgroundThe association between recurrent aphthous stomatitis (RAS) and neoplasms of the mouth and pharynx (NOMAP) has been reported in some previous observational studies. However, causality is still confused. Our research aims to explore the relationship between RAS and NOMAP through a Mendelian randomization (MR) analysis and to explore whether RAS can serve as a risk factor for NOMAP to provide a reference for the clinical strategy.MethodsAn exposure dataset for RAS were collected from a published study based on the UK Biobank (UKB). Outcome datasets included Genome-wide association studies (GWAS) summary statistics of NOMAP from the FinnGen datasets. The core method was inverse variance weighting (IVW). The Bonferroni correction, MR-Egger, weighted median, weighted mode, Cochcan’s Q test, MR-PRESSO, and leave-one-out methods served as complementary methods.ResultsWe found no significant evidence of causal relationships between RAS and NOMAP. After applying the Bonferroni correction, the corrected P was equal to 0.00625 (0.05/1/8). The IVW method provided the sole evidence for RAS on Benign neoplasm of floor of mouth (BNFM) (OR = 2.509, 95% CI: 1.296–4.857, P = 0.006), but the subsequent MR-Egger regression method showed that this result may be due to horizontal pleiotropy (P = 0.035). The Cochran Q-test, MR-Egger regression, and MR-PRESSO did not reveal any heterogeneity or directional pleiotropy for the other outcomes.ConclusionsIn conclusion, this is the first MR analysis to investigate the relationship between RAS and NOMAP. Our research confirmed at the genetic level that no causal association has been identified between RAS and NOMAP, therefore facilitating a logical therapeutic perspective and the development of clinical therapies for them.

Association and mediation pathways of maternal hyperglycaemia and liability to gestational diabetes with neonatal outcomes: A two-sample Mendelian randomization study.

Maternal hyperglycemia is linked to adverse neonatal outcomes. However, current evidence was insufficient for mechanistic pathways. We aim to use two-sample Mendelian randomization (MR) to obtain a comprehensive understanding of the causal association and mediation pathways. Genetic variants of fasting glucose (FG), insulin sensitivity index (ISI), glycated haemoglobin (HbA1c), gestational diabetes mellitus (GDM) and type 2 diabetes (T2D) were used as instruments (N = 50 404-898 130). The associations with offspring birthweight, gestational duration, spontaneous preterm and post-term birth were assessed by the inverse-variance weighted method, using summary statistics of European genome-wide association studies (N = 131 279-210 248). Sensitivity analyses, including multivariable MR removing pleiotropic effect from maternal body mass index (BMI), assessed the robustness. Mediation via placental weight and maternal hypertension were assessed via a two-step MR design. FG (0.46 SD per mmol/L, 95% confidence interval [95% CI]: 0.32, 0.61) and GDM liability (0.18 SD per log odds, 95% CI: 0.08, 0.18) were positively associated with birthweight, with consistent findings for HbA1c, T2D liability and ISI. These associations were mediated by placental weight (proportion mediated: 32.8% to 77.7%). Higher HbA1c, GDM and T2D liability were associated with preterm birth (odds ratios for GDM: 1.07, 95% CI: 1.01, 1.14) and shorter gestational duration, whilst the association for T2D attenuated after adjusted for maternal BMI and gestational hypertension. Maternal hyperglycemia is associated with higher birthweight (possibly indicating macrosomia), mediated via increased placental growth. GDM and T2D liability are related to preterm birth, whilst the association for T2D liability is driven by maternal adiposity.

The relationship between pulmonary ventilation function and bone marrow hematopoietic function: A mendelian randomization analysis

Background: In recent years, the comorbidity between respiratory and hematopoietic system diseases has emerged as a new challenge. However, the potential genetic link between the ventilatory function of the respiratory system and the hematopoietic function of the bone marrow remains unclear. In this study, we conducted a comprehensive investigation into the possible genetic connection between lung ventilatory function and bone marrow hematopoietic function. Methods: We selected two exposure factors, Forced Expiratory Volume in 1 second (FEV1) and Forced Vital Capacity (FVC), which represent pulmonary ventilation function, and two outcome indicators, Immature Fraction of Reticulocytes (IFR) and Reticulocyte Count (RC), which represent bone marrow hematopoiesis function, from published genome-wide association studies. Based on the three core assumptions of Mendelian randomization analysis, we extracted Single Nucleotide Polymorphism (SNPs) associated with FEV1 and FVC as instrumental variables for the exposure factors. We then conducted two-sample Mendelian randomization analyses using inverse variance weighted (IVW), weighted median, and MR-Egger regression methods. Lastly, we assessed the reliability of the testing results through MR-Egger, Cochran’s Q test, and the leave-one-out test. Through these steps, we aimed to explore the causal relationship between pulmonary ventilation function and the outcome of bone marrow hematopoiesis function and evaluated the reliability of the testing results using methods such as MR-Egger, Cochran’s Q test, and the leave-one-out test. Results: The IVW method revealed that a decrease in FEV1 is associated with an increase in IFR (β = −0.072, 95% CI: −0.131 to −0.014, p = 0.01), and the results from MR-Egger regression showed a similar association (β = −0.169, 95% CI: −0.342 to −0.004, p = 0.05). Furthermore, a decrease in FEV1 is associated with an increase in RC (β = −0.143, 95% CI: −0.198 to −0.087, p =4.00E-07), and MR-Egger regression yielded consistent results (β = −0.216, 95% CI: −0.381 to −0.541, p=1.07E-02). Similarly, a decrease in FVC is associated with an increase in IFR (β = −0.073, 95% CI: −0.116 to −0.031, p = 6.17E-04), and MR-Egger regression showed a similar trend (β = −0.046, 95% CI: −0.160 to −0.067, p=0.42). Additionally, a decrease in FVC is associated with an increase in RC (β = −0.173, 95% CI: −0.221 to −0.125, p = 2.33E-12), and MR-Egger regression yielded consistent results (β = −0.142, 95% CI: −0.272 to −0.012, p = 3.32E-02). The reliability tests indicated heterogeneity in the above MR analyses but no evidence of horizontal pleiotropy. Therefore, a fixed-effect model IVW was used to explore the causal relationships, which were found to be robust and reliable with no outliers or significant bias in this study. Conclusion: This study indicates that there is a negative causal relationship between pulmonary ventilation function and bone marrow hematopoietic function. A decrease in pulmonary ventilation function stimulates bone marrow hematopoiesis. However, further research is needed to elucidate this mechanism.

Impact of immune cells on the risk of frozen shoulder: A 2-sample Mendelian randomization study.

The pathogenesis of frozen shoulder (FS) remains unclear, and current research primarily focuses on immune responses. Increasing evidence suggests that immune cells play a significant role in FS development. However, the causal relationship between the two remains poorly understood. Therefore, we aimed to investigate this using Mendelian randomization (MR) analysis. Single nucleotide polymorphisms closely associated with 731 immune phenotypes were obtained from publicly available GWAS datasets as instrumental variables. FS was used as the outcome with a sample size of 451,099 cases. Causal effects were analyzed using the inverse variance-weighted method. We conducted sensitivity tests, including the intercept of the MR-Egger and MR-PRESSO analyses. The presence of heterogeneity was evaluated using Cochran Q test. We identified potential causal relationships in terms of increased risk for FS with 5 immune phenotypes: CD25++ CD45RA+ CD4 not regulatory T cell %CD4+ T cells (odds ratio [OR] = 1.0273, 95% confidence interval [CI]: 1.0093-1.0457, P = .0028), CD25++ CD45RA+ CD4 not regulatory T cell %T cell (OR = 1.0240, 95% CI: 1.0057-1.0427, P = .0098), CD127 on CD28+ CD4+ T cells (OR = 1.0398, 95% CI: 1.0121-1.0682, P = .0046), CD4 on human leukocyte antigen DR+ CD4+ T cells (OR = 1.0795, 95% CI: 1.0316-1.2195, P = .0009), and human leukocyte antigen DR on CD14- CD16+ monocytes (OR = 1.0533, 95% CI: 1.0136-1.0945, P = .0081). Few significant heterogeneities or horizontal pleiotropies were observed. Through MR analysis, we identified distinct 5 types of immune cells that were positively correlated with the occurrence and development of FS, providing guidance for clinical intervention in FS.

Genetically Predicted Sleep Traits and Sensorineural Hearing Loss: A Mendelian Randomization Study.

Observational studies suggest a potential association between sleep characteristics, sensorineural hearing loss (SNHL), and sudden SNHL (SSNHL), but causal evidence is scarce. We sought to clarify this issue using two-sample Mendelian randomization analysis. The inverse-variance weighted (IVW) method was performed as primary analysis to assess bidirectional causal associations between sleep traits (chronotype, sleep duration, insomnia, daytime sleepiness, and snoring) and SNHL/SSNHL using publicly available Genome-Wide Association Studies summary data from two large consortia (UK Biobank and FinnGen). Sensitivity analyses, including Mendelian randomization (MR)-Egger, Mendelian randomization pleiotropy residual sum and outlier, weight median, Cochran's Q test, leave-one-out analysis, and potential pleiotropy analysis, were conducted to ensure robustness. IVW analysis found suggestive associations of morning chronotype (odds ratio [OR] = 1.08, 95% confidence interval [CI] = 1.01-1.16, p = 0.031) and daytime sleepiness (OR = 1.88, 95% CI = 1.24-2.87, p = 0.003) with SNHL onset. Additionally, morning chronotype was nominally associated with SSNHL onset using IVW method (OR = 1.37, 95% CI = 1.10-1.71, p = 0.006). However, there was no evidence for the causal effect of SNHL and SSNHL on different sleep traits (all p > 0.05). Sensitivity analysis showed that the results were stable. Within the MR limitations, morning chronotype and daytime sleepiness were underlying causal contributors to the burden of SNHL, indicating that optimal sleep might facilitate the prevention and development of SNHL. 3 Laryngoscope, 134:4723-4729, 2024.

Investigating the causal association between heme oxygenase-1 and asthma: A bidirectional two-sample Mendelian randomization analysis in a European population

BackgroundThe association between heme oxygenase-1 (HO-1) and asthma has been a subject of debate in both observational and experimental studies. We aimed to evaluate the potential causal relationship between HO-1 and asthma. Materials and methodsA bidirectional two-sample Mendelian randomization (TSMR) study was conducted to examine the causal relationship between HO-1 and asthma. In the forward Mendelian randomization (MR) analyses, HO-1 was considered as the exposure, while asthma as the outcome. Conversely, in the reverse MR analyses, asthma was regarded as the exposure, and HO-1 as the outcome. Data for HO-1 and asthma were obtained from publicly accessible genome-wide association studies (GWAS). These causal relationships were identified through 5 MR methods, namely MR-Egger, weighted median, inverse-variance weighted (IVW), simple mode, and weighted mode. Additionally, sensitivity tests were conducted to assess the robustness of MR study. Finally, additional asthma datasets and childhood asthma were selected to validate the findings. ResultsIn the forward MR analyses, according to the IVW method, genetically predicted HO-1 displays a negative correlation with the risk of asthma (OR 0.947, 95% CI 0.905–0.990). It was not found any SNP overly sensitive or disproportionately responsible for the outcome. No evidence of heterogeneity and pleiotropy between SNPs was observed. Genetically predicted asthma was not associated with HO-1 in reverse MR analyses using the IVW method. The same results were validated in additional asthma datasets and in childhood asthma. ConclusionThe results of MR analysis revealed heme oxygenase-1 as a protective factor for asthma.

Relationship between myocardial infarction and atrial fibrillation: A bidirectional Mendelian randomization study.

Many studies have shown that myocardial infarction (MI) is significantly associated with atrial fibrillation (AF), but the causal relationship between MI and AF has not been established. Therefore, we performed this Mendelian randomization (MR) study to investigate the relationship between MI and AF. We used a publicly available summary statistical dataset for MI based on genome-wide analysis studies (GWAS; ebi-a-GCST011364; 14,825 cases and 2680 controls) and a summary statistical dataset for AF based on an European GWAS (finn-b-I9_AF_REIMB; 10,516 cases and 116,926 controls). The 2-sample bidirectional MR analysis was performed using the inverse-variance weighted (IVW), MR-Egger, and weighted median methods. The causal effect of MI on AF was analyzed using 30 MI-specific single nucleotide polymorphisms (SNPs) that were characterized as instrumental variables (IVs) based on the GWAS data. The causal effect of MI on AF was confirmed by the IVW (odds ratio [OR] 1.42; 95% confidence interval [CI] 1.27-1.58; P < .001), MR-Egger (OR: 1.49; 95% CI: 1.15-1.93; P = .005), and weighted median (OR: 1.42; 95% CI: 1.24-1.63; P < .001) analyses. Furthermore, in the reverse MR analyses, the causal effect of AF on MI was analyzed using 20 AF-specific SNPs that were screened as IVs. The causal effect of AF on MI was significant based on the results from the IVW method (OR: 1.05; 95% CI: 1.00-1.09; P = .033). In conclusion, the bidirectional MR analyses demonstrated a clear bidirectional causal association between MI and AF.

Association between frailty and common psychiatric disorders: A bidirectional Mendelian randomization study

BackgroundThere is growing interest in exploring the relationship between frailty and common psychiatric disorders. However, there have been limited reports on the genetic variation level of frailty with psychiatric disorders. MethodWe conducted large-scale Two-sample Mendelian randomization (MR) analyses to examine whether there is an association between frailty and common psychiatric disorders (bipolar disorder [BD], major depressive disorder [MDD], schizophrenia, and suicide or other Intentional self-harm). We employed multiple MR approaches to conduct the MR analysis, including MR-Egger, weighted median, and random-effect inverse variance weighted (IVW). The IVW method served as the primary analysis. Heterogeneity testing and sensitivity analysis were also conducted in the MR study. ResultsThe MR results denoted that frailty was associated with an increased risk of BD (odds ratio (OR) =1.60, PIVW = 0.017), MDD (OR = 2.04, PIVW < 0.001), schizophrenia (OR = 1.91, PIVW = 0.005), and suicide or other Intentional self-harm (OR = 1.77, PIVW < 0.001). For reverse analysis, we observed no significant association between psychiatric disorders and the risk of frailty. These results remained consistent across sensitivity assessments. ConclusionsOur research indicates a potential unidirectional causal relationship, suggesting that frailty may serve as a risk factor for certain common psychiatric disorders. These findings carry important for implications for psychiatric disorders and frailty patient care.

Gastroesophageal reflux disease, mood swings, and frozen shoulder: A two-sample, two-step Mendelian randomization study.

A Mendelian randomization (MR) study was undertaken to establish a causal link between gastroesophageal reflux disease (GERD) and frozen shoulder (FS), examining whether the risk of GERD with FS is mediated through mood fluctuations. Genetic loci from populations of independent European ancestry were selected as instrumental variables for GERD, FS, and mood swings. The primary analysis employed the inverse-variance weighted method supplemented by 3 additional analytical methods. This was conducted using two-sample and two-step MR analyses. This study explored the correlation and mediating effects of mood swings between GERD and FS. Our study employed heterogeneity and horizontal diversity, and sensitivity analysis was conducted using the leave-one-out method to explore the robustness of the results. In the two-sample MR analysis, for every 1-unit increase in the log-transformed odds ratio (OR) of GERD, the corresponding OR increased to 1.844 (inverse-variance weighting: OR = 1.844, 95% confidence interval: 1.47-2.30, P < .001). In the two-step MR analysis, we found that mood swings played a mediating role in the association between GERD and FS. We assessed this mediating effect using the delta method (b = 0.181, SE = 0.059, OR = 1.199, 95% confidence interval: 1.072-1.349). Analysis of the data using the above methods indicated that GERD is a risk factor for FS, and mood swings mediate between the 2. Therefore, GERD and mood swings should be included in the health management of patients with FS.

Education and metabolic syndrome: a Mendelian randomization study.

The metabolic syndrome (MetS), a collection of conditions that heighten the risk of disease development and impose economic burdens on patients. However, the causal relationship between education and MetS was uncertain. In this study, the Mendelian randomization (MR) method was employed to elucidate the potential causal link between education and the MetS and its components. Single nucleotide polymorphisms (SNPs) associated with education, MetS, and its components were sourced from a public database, with the inverse variance-weighted (IVW) method utilized for analysis. Education demonstrated a significant negative correlation with the risk of MetS (OR = 0.55, 95% CI = 0.48-0.63, p = 2.18E-51), waist circumference(OR = 0.80, 95% CI = 0.76-0.83, p = 4.98E-33), hypertension (OR = 0.96, 95% CI = 0.95-0.97; p = 4.54E-10), Fasting blood glucose (OR = 0.94, 95% CI = 0.91-0.97, p = 7.58E-6) and triglycerides (OR = 0.83, 95% CI = 0.79-0.87, p = 7.87E-18) while showing a positive association with high-density lipoprotein cholesterol (OR = 1.22, 95% CI = 1.18-1.25, p = 1.45E-31). The findings of this study suggest that education can decrease the incidence of MetS.

Association between dietary tea consumption and non-alcoholic fatty liver disease: a study based on Mendelian randomisation and National Health and Nutrition Examination Survey (2005-2018) association between tea and non-alcoholic fatty liver disease.

Tea can improve the progression of some metabolic diseases through anti-inflammatory and antioxidant effects, but its impact on non-alcoholic fatty liver disease (NAFLD) is still controversial. The aim of this paper is to identify the relationship between tea and NAFLD by Mendelian randomisation (MR) and complete clinical validation using National Health and Nutrition Examination Survey (NHANES) database. MR used data from Genome Wide Association Study, with inverse-variance weighted (IVW) as principal analytical methods. The reliability of the results was verified by a series of sensitivity and heterogeneity tests. Subsequently, clinical validation was conducted using NHANES (2005-2018), involving 22257 participants, grouped by the type of tea. Green tea drinkers were categorised into four groups (Q1-Q4) by quartiles of green tea intake, from lowest to highest (similar for black tea drinkers and other tea drinkers). Models were constructed by logistic regression to estimate the role of tea consumption (Q1-4) on NAFLD. Finally, using fibrosis-4 index (FIB-4) to evaluate the severity of hepatic fibrosis, the effect of tea consumption (Q1-4) on the degree of hepatic fibrosis was investigated by linear regression. IVW method (OR = 0·43, 95 % CI: 0·21, 0·85, P = 0·01) and weighted median method (OR = 0·35, 95 % CI: 0·14, 0·91, P = 0·03) revealed there was a causal relationship between tea and NAFLD. An array of sensitivity analyses validated the reliability of results. Analysis of NHANES indicated tea drinker present a slightly lower prevalence of NAFLD than non-tea drinker (green tea drinkers: 47·6 %, black tea drinkers: 46·3 %, other tea drinker: 43·2 %, non-tea drinkers: 48·1 %, P < 0·05). After adjusting for confounders, compared with the lowest black tea consumption (Q1), the population with the highest black tea consumption (Q4) was independently related to lower presence of NAFLD (Q4: OR = 0·69, 95 % CI: 0·50, 0·93, P < 0·05), such association remained stable in the overweight subgroup. As further analysed, Q4 also displayed a significant negative correlation with the level of hepatic fibrosis in patients with NAFLD (β = -0·073, 95 % CI: -0·126, -0·020, P < 0·01).Tea reduces the morbidity of NAFLD and ameliorates hepatic fibrosis degree in those already suffering from the disease.

Association between venous thromboembolism and atrial fibrillation: a Mendelian randomization study

BackgroundAlthough previous observational studies have shown an association between venous thromboembolism (VTE) and atrial fibrillation (AF), the underlying causal relationship between them remains uncertain.Methods and resultsThis two-sample bidirectional Mendelian randomization (MR) analysis was performed to investigate the causal relationship between VTE and AF. The VTE dataset were obtained from FinnGen, including 9,176 cases and 209,616 controls. Meanwhile a genome-wide association study (GWAS) of 60,620 individuals with AF and 970,216 control subjects identified genetic variations associated with AF. The principal MR analytic approach used in this study is the inverse-variance weighting (IVW) method. Furthermore, we performed complementary MR analyses, including the MR-Egger, Weighted median (WM), and Weighted Mode. MR pleiotropy residual sum was applied to identify pleiotropy. The MR analysis showed suggestive causal associations between VTE and the risk of AF (p = 0.0245, OR [95%CI]: 1.027 [1.003, 1.051]). The reverse MR analysis found that genetic susceptibility to AF was not significantly associated with VTE, as determined by the IVW method (p = 0.7773). The robustness of these findings was corroborated through MR sensitivity analyses.ConclusionsThere is a unidirectional causal relationship between VTE and AF, meaning that VTE is a causal risk factor for AF, whereas no effect of AF on VTE was identified.

Association between asthma and depression: results from the NHANES 2005-2018 and Mendelian randomization analysis.

Asthma is a common respiratory disease that is believed to be associated with mental disorders. This study aims to assess the correlation and causal relationship between asthma and depression by combining observational and Mendelian randomization (MR) approaches. We collected relevant data from the National Health and Nutrition Examination Survey (NHANES) and employed multivariable logistic regression to evaluate the correlation between asthma and depression. Additionally, a two-sample MR analysis was conducted using inverse variance-weighted (IVW) method, along with multiple sensitivity analyses. The observational study included a total of 23 648 participants, and the results showed that asthma patients had an increased risk of developing depression compared to non-asthma individuals (OR 1.26; 95% CI 1.04-1.57; P < 0.01). The IVW-MR results from two datasets indicated a potential causal relationship between asthma and depression (EBI dataset: OR 1.141; 95% CI 1.051-1.239; P = 0.01; UKB dataset: OR 1.009; 95% CI 1.005-1.013; P < 0.01). These findings suggest that asthma may be a risk factor for the onset of depression, increasing the risk of developing depression. There is a significant correlation and potential causal relationship between asthma and depression, with asthma being a risk factor for the onset of depression. These findings warrant further research for validation and exploration of preventive and therapeutic measures for depression in asthma patients. Key messages What is already known on this topic-There are some potential associations between asthma and depression based on observational studies, but the results of observational studies are often biased. This study aims to further explore the relationship between asthma and depression through a combination of observational studies and Mendelian randomization (MR) analysis. What this study adds-The observational study results from the National Health and Nutrition Examination Survey database and MR analysis are consistent, indicating that after adjusting for multiple covariates and confounding factors, asthma increases the risk of depression and is a risk factor for depression, with similar results obtained at the genetic level. How this study might affect research, practice or policy-Asthma patients not only need active medication treatment, but also need timely psychological attention, and psychological treatment is more important to a certain extent.

Appraising the Role of Circulating Concentrations of Micronutrients in Hypertension: A Two-sample, Multivariable Mendelian Randomization Study.

Hypertension poses a significant global health challenge, warranting exploration of novel preventive measures. This study aimed to investigate the role of circulating concentrations of various micronutrients in hypertension using a Mendelian randomization (MR) approach. Data on hypertension were obtained from FinnGen, comprising 55,917 cases and 162,837 controls of European ancestry. Fifteen micronutrients were evaluated and selected based on genome-wide association studies (GWAS) data. Instrumental single nucleotide polymorphisms (SNPs) were chosen according to strict criteria. Univariable Mendelian randomization (UVMR) analysis was conducted using the inverse variance weighted (IVW) method, supplemented by sensitivity analyses. Multivariate Mendelian randomization (MVMR) analysis was performed to assess interactions between micronutrients. In UVMR analysis, the IVW method revealed a potential influence of copper (OR = 1.052, 95% CI: 1.006-1.099, P = 0.025) and zinc (OR = 1.083, 95% CI: 1.007-1.165, P = 0.031) on hypertension. Sensitivity analyses supported these findings. MVMR analysis confirmed a direct positive effect of zinc on hypertension (OR = 1.087, 95% CI: 1.026-1.151, P = 0.005), while adjusting for zinc attenuated the effect of copper on hypertension (OR = 1.026, 95% CI: 0.987-1.066, P = 0.193). Circulating zinc levels may be a potential risk factor for hypertension, while the association with other micronutrients remains inconclusive. These findings suggest that reducing zinc intake within a healthy range may help lower hypertension risk. Future research should further explore the role of zinc and nonlinear associations for a more comprehensive understanding.