2-sample Mendelian Randomization Research Articles

Association of Body Mass Index and Parkinson Disease: A Bidirectional Mendelian Randomization Study.

The role of body mass index (BMI) in Parkinson disease (PD) is unclear. Based on the Comprehensive Unbiased Risk Factor Assessment for Genetics and Environment in PD (Courage-PD) consortium, we used 2-sample Mendelian randomization (MR) to replicate a previously reported inverse association of genetically predicted BMI with PD and investigated whether findings were robust in analyses addressing the potential for survival and incidence-prevalence biases. We also examined whether the BMI-PD relation is bidirectional by performing a reverse MR. We used summary statistics from a genome-wide association study (GWAS) to extract the association of 501 single-nucleotide polymorphisms (SNPs) with BMI and from the Courage-PD and international Parkinson Disease Genomics Consortium (iPDGC) to estimate their association with PD. Analyses are based on participants of European ancestry. We used the inverse-weighted method to compute odds ratios (ORIVW per 4.8 kg/m2 [95% CI]) of PD and additional pleiotropy robust methods. We performed analyses stratified by age, disease duration, and sex. For reverse MR, we used SNPs associated with PD from 2 iPDGC GWAS to assess the effect of genetic liability toward PD on BMI. Summary statistics for BMI are based on 806,834 participants (54% women). Summary statistics for PD are based on 8,919 (40% women) cases and 7,600 (55% women) controls from Courage-PD, and 19,438 (38% women) cases and 24,388 (51% women) controls from iPDGC. In Courage-PD, we found an inverse association between genetically predicted BMI and PD (ORIVW 0.82 [0.70-0.97], p = 0.012) without evidence for pleiotropy. This association tended to be stronger in younger participants (≤67 years, ORIVW 0.71 [0.55-0.92]) and cases with shorter disease duration (≤7 years, ORIVW 0.75 [0.62-0.91]). In pooled Courage-PD + iPDGC analyses, the association was stronger in women (ORIVW 0.85 [0.74-0.99], p = 0.032) than men (ORIVW 0.92 [0.80-1.04], p = 0.18), but the interaction was not statistically significant (p-interaction = 0.48). In reverse MR, there was evidence for pleiotropy, but pleiotropy robust methods showed a significant inverse association. Using an independent data set (Courage-PD), we replicate an inverse association of genetically predicted BMI with PD, not explained by survival or incidence-prevalence biases. Moreover, reverse MR analyses support an inverse association between genetic liability toward PD and BMI, in favor of a bidirectional relation.

Genome-Wide Mendelian Randomization Study Reveals Druggable Genes for Cerebral Small Vessel Disease.

Cerebral small vessel disease (CSVD) is a group of neurological disorders that affect the small blood vessels within the brain, for which no effective treatments are currently available. We conducted a Mendelian randomization (MR) study to identify candidate therapeutic genes for CSVD. We retrieved genome-wide association study data from 6 recently conducted, extensive investigations focusing on CSVD magnetic resonance imaging markers and performed a 2-sample MR analysis to assess the potential causal effects of gene expression and protein level within druggable genes on CSVD in blood and brain tissues. Colocalization analyses and repeat studies were undertaken to verify the relationship. Additionally, mediation analysis was conducted to explore the potential mechanisms involving druggable genes and known risk factors for CSVD. Finally, phenome-wide MR analyses were applied to evaluate the potential adverse effects related to the identified druggable genes for CSVD treatment. Overall, 5 druggable genes consistently showed associations with CSVD in MR analyses across both the discovery and validation cohorts. Notably, the ALDH2 and KLHL24 genes were identified as associated with CSVD in both blood and brain tissues, whereas the genes ADRB1, BTN3A2, and EFEMP1 were exclusively detected in brain tissue. Moreover, mediation analysis elucidated the proportion of the total effects mediated by CSVD risk factors through candidate druggable genes, which ranged from 5.5% to 18.5%, and offered potential explanations for the observed results. A comprehensive phenome-wide MR analysis further emphasized both the therapeutic benefits and potential side effects of targeting these candidate druggable genes. This study provides genetic evidence supporting the potential therapeutic benefits of targeting druggable genes for treating CSVD, which will be useful for prioritizing CSVD drug development.

Association between diabetes mellitus and giant cell arteritis: a bidirectional 2-sample mendelian randomization study

ObjectiveRecent studies have indicated a potential association between giant cell arteritis (GCA) and diabetes mellitus, encompassing both type 1 diabetes (T1D) and type 2 diabetes (T2D). However, the exact nature of this relationship requires further investigation to be fully elucidated.MethodsGenetic links between T1D/T2D and GCA were explored using data from genome-wide association studies available to the public, focusing on populations of European ancestry. We applied a bidirectional mendelian randomization (MR) approach to assess the potential association between these diseases. Confirmatory analyses, including additional datasets and a comprehensive meta-analysis, were utilized. The inverse-variance-weighted (IVW) method was applied to pinpoint heterogeneity and pleiotropy, while subsequent sensitivity analyses aimed to trace the origins of any heterogeneity.ResultsInitial analysis demonstrated a correlation between T1D and an elevated likelihood of developing GCA (IVW odds ratio = 1.33, with a 95% confidence interval of 1.22–1.46, and a P-value of 9.42E−10). The causal association was verified through four validation datasets and meta-analysis (all P-value < 0.001). However, the reverse MR analysis was unable to detect any genetic basis for the increased risk of T1D due to GCA. Furthermore, we could not establish any causal links between T2D and GCA.ConclusionT1D patients may have a higher risk of developing GCA, whereas an inverse causal relationship was not evident. Furthermore, no causal relationship was detected between T2D and GCA. These insights shed light on the possible pathological mechanisms underlying GCA and may influence the future clinical handling of both T1D and GCA.

Impact of thyroid function on coagulation and venous thromboembolism: a two-sample mendelian randomization study.

The association between thyroid function, coagulation and venous thromboembolism (VTE) has been reported in observational studies with conflicting findings. This study aimed to elucidate the causal effects of thyroid function on coagulation and VTE from a genetic perspective. Two sample Mendelian randomization analysis was conducted using summary statistics from genome-wide association studies in a European population. Coagulation status was associated with nine coagulation-related factors (F VIII, F IX, F XI, Fibrinogen, Antithrombin-III, Thrombomodulin, Plasminogen activator inhibitor-1, Protein C and Protein S). Inverse variance weighting with random effect method was used as the main analytic approach with MR-Egger, weighted median, simple mode and weighted mode methods serving as complements. Sensitivity analyses including heterogeneity test, horizontal pleiotropy test and leave-one-out analysis were conducted to further assess the reliability of results. No genetic causal effects of thyroid function on VTE (including pulmonary embolism and deep venous thrombosis) were found. Genetically, hyperthyroidism was suggestively related to decreased Antithrombin-III (β: -0.04 [95% CI: -0.06 to - 0.01], p = 0.010) and Protein C (β: -0.03 [95% CI: -0.06 to 0.00], p = 0.045). No notable associations were observed between other thyroid function parameters and coagulation-related factors. We provide suggestive genetic evidence supporting the causal effect of hyperthyroidism on decreased level of anticoagulant factors including Antithrombin-III and Protein C. However, whether this genetic causality could lead to clinically significant hypercoagulable state and increased risk of VTE in hyperthyroid population needs to be further addressed.

Childhood Adiposity and Risk of Major Clinical Heart Diseases in Adulthood: A Mendelian Randomization Study.

The causal relationship between childhood adiposity and adult risk of heart diseases has not been clearly demonstrated. This study aims to ascertain whether genetically predicted childhood body mass index (BMI) and childhood obesity are causally associated with adult coronary heart disease, myocardial infarction, heart failure, atrial fibrillation, hypertrophic cardiomyopathy, and pulmonary heart disease. To investigate the causative relationships and underlying mechanisms between childhood adiposity and adult heart diseases, 3 main methods of Mendelian randomization were used: 2-sample Mendelian randomization, multivariable Mendelian randomization with controlling for several cardiometabolic risk variables, and mediation analysis. Every 1-SD rise in genetically predicted childhood body mass index was associated with 24% (odds ratio [OR], 1.24 [95% CI, 1.12-1.37]), 28% (OR, 1.28 [95% CI, 1.14-1.42]), 28% (OR, 1.28 [95% CI, 1.14-1.42]), and 27% (OR, 1.27 [95% CI, 1.04-1.49]) higher risk of coronary heart disease, myocardial infarction, heart failure, and atrial fibrillation, respectively. Every 1-unit increase in log-odds in childhood obesity was associated with 11% (OR, 1.11 [95% CI, 1.06-1.16]), 14% (OR, 1.14 [95% CI, 1.04-1.23]), 10% (OR, 1.10 [95% CI, 1.03-1.18]), and 20% (OR, 1.20 [95% CI, 1.08-1.32]) higher risk of coronary heart disease, myocardial infarction, heart failure, and atrial fibrillation, respectively. The link between childhood adiposity and adult heart diseases was found to be mediated by high-density lipoprotein cholesterol, triglyceride, hypertension, and type 2 diabetes. Our findings support the causal relationships between childhood adiposity and risk of adult coronary heart disease, myocardial infarction, heart failure, and atrial fibrillation. Blood lipids, hypertension, and type 2 diabetes are factors that mediate the aforementioned associations.

Primary Aldosteronism and Risk of Cardiovascular Outcomes: Genome-Wide Association and Mendelian Randomization Study.

Observational studies have reported associations between primary aldosteronism (PA) and cardiovascular outcomes, including coronary artery diseases (CAD), congestive heart failure (CHF), and stroke. However, establishing causality remains a challenge due to the lack of randomized controlled trial data on this topic. We thus aimed to investigate the causal relationship between PA and the risk of developing CAD, CHF, and stroke. Cross-ancestry meta-analysis of genome-wide association studies combining East Asian and European ancestry (1560 PA cases and 742 139 controls) was conducted to identify single-nucleotide variants that are associated with PA. Then, using the identified genetic variants as instrumental variables, we conducted the 2-sample Mendelian randomization analysis to investigate the causal relationship between PA and incident CAD, CHF, and stroke among both East Asian and European ancestry. Summary association results were extracted from large genome-wide association studies consortia. Our cross-ancestry meta-analysis of East Asian and European populations identified 7 genetic loci significantly associated with the risk of PA, for which the genes nearest to the lead variants were CASZ1, WNT2B, HOTTIP, LSP1, TBX3, RXFP2, and NDP. Among the East Asian population, the pooled odds ratio estimates using these 7 genetic instruments of PA were 1.07 (95% CI, 1.03-1.11) for CAD, 1.10 (95% CI, 1.01-1.20) for CHF, and 1.13 (95% CI, 1.09-1.18) for stroke. The results were consistent among the European population. Our 2-sample Mendelian randomization study revealed that PA had increased risks of CAD, CHF, and stroke. These findings highlight that early and active screening of PA is critical to prevent future cardiovascular events.

Bidirectional two-sample Mendelian randomization analysis identifies causal associations between migraine and five psychiatric disorders

BackgroundThe question of whether a correlation exists between migraine and five psychiatric disorders, including posttraumatic stress disorder (PTSD), major depressive disorder (MDD), anorexia nervosa (AN), bipolar disorder (BIP), and schizophrenia (SCZ), remains a matter of controversy. Hence, this research aims to investigate whether there is a possible association between migraine and five psychiatric disorders.MethodsWe performed a bidirectional 2-sample Mendelian randomization (MR) analysis to assess the causality between migraine and five psychiatric disorders. Genetic associations of PTSD, MDD, AN, BIP, and SCZ were obtained from the Psychiatric Genomics Consortium (PGC) database and genetic associations of migraine with aura and migraine without aura were obtained from the FinnGen dataset. We used the inverse-variance weighted (IVW), weighted median, weighted mode, MR Pleiotropy RESidual Sum and Outlier (MR-PRESSO), and MR Egger regression methods to evaluate the association of genetically predicted exposure with the risk of outcome.ResultsMR demonstrated that MDD was associated with a high risk of migraine without aura (OR = 1.930578, 95% confidence interview (CI): 1.224510, 3.043550, p &amp;lt; 0.05), but BIP was related to a low risk of migraine without aura (OR = 0.758650, 95%CI: 0.639601, 0.899858, p &amp;lt; 0.05). According to the results of reverse MR, migraine with aura was associated with a high risk of BIP (OR = 1.019100, 95%CI: 1.002538, 1.035935, p &amp;lt; 0.05), and migraine without aura was associated with an increased risk of AN (OR = 1.055634, 95%CI: 1.023859, 1.088394, p &amp;lt; 0.05).ConclusionOur results provide evidence of the potential causal association between migraine and some psychiatric disorders. It may contribute to the prevention of migraine and some psychiatric disorders.

Causal relationship between gut microbiota and ankylosing spondylitis and potential mediating role of inflammatory cytokines: A mendelian randomization study.

Associations between gut microbiota and ankylosing spondylitis have been discovered in previous studies, but whether these associations reflect a causal relationship remains inconclusive. Aiming to reveal the bidirectional causal associations between gut microbiota and ankylosing spondylitis, we utilized publicly available genome wide association study summary data for 211 gut microbiota (GM) taxa and ankylosing spondylitis (AS) to conduct two sample mendelian randomization analyses. Mediation analysis was performed to explore mediating inflammatory cytokines. We found that genetically predicted higher abundance of Lactobacillaceae family, Rikenellaceae family and Howardella genus had suggestive associations with decreased risk of ankylosing spondylitis while genetic proxied higher abundance of Actinobacteria class and Ruminococcaceae_NK4A214_group genus was associated with increased risk of ankylosing spondylitis. IL23 and IFN-γ were potential mediating cytokines for GM dysbiosis, especially for Actinobacteria class, leading to AS. Our study provided a new exploration direction for the treatment of AS. Lactobacillaceae family, Rikenellaceae family, Howardella genus, Actinobacteria class and Ruminococcaceae_NK4A214_group genus are expected to become new therapeutic targets and monitoring indicators for AS.

Visual Impairment, Eye Conditions, and Diagnoses of Neurodegeneration and Dementia

Vision and eye conditions are associated with increased risk for Alzheimer disease and related dementias (ADRDs), but the nature of the association and the underlying biological pathways remain unclear. If causal, vision would be an important modifiable risk factor with viable population-level interventions. To evaluate potentially causal associations between visual acuity, eye conditions (specifically cataracts and myopia), neuroimaging outcomes, and ADRDs. A cohort and 2-sample bidirectional mendelian randomization (MR) study was conducted using UK Biobank participants and summary statistics from previously published genome-wide association studies on cataract, myopia, and AD. The participants included in the analysis were aged 55 to 70 years without dementia at baseline (calendar years 2006 to 2010), underwent genotyping, and reported on eye conditions; a subset completed visual acuity examinations (n = 69 852-71 429) or brain imaging (n = 36 591-36 855). Data were analyzed from August 15, 2022, through November 28, 2023. Self-reported cataracts, visual acuity, and myopia measured by refraction error. ADRD, AD, and vascular dementia were identified from electronic medical records. Total and regional brain volumes were determined using magnetic resonance imaging. The sample included 304 953 participants (mean [SD] age, 62.1 (4.1) years; 163 825 women [53.72%]); 14 295 (4.69%) had cataracts and 2754 (3.86%) had worse than 20/40 vision. Cataracts (hazard ratio [HR], 1.18; 95% CI, 1.07-1.29) and myopia (HR, 1.35; 95% CI, 1.06-1.70) were associated with a higher hazard of ADRD. In MR analyses to estimate potential causal effects, cataracts were associated with increased risk of vascular dementia (inverse variance-weighted odds ratio [OR], 1.92; 95% CI, 1.26-2.92) but were not associated with increased dementia (OR, 1.21; 95% CI, 0.98-1.50). There were no associations between myopia and dementia. In MR for potential reverse causality, AD was not associated with cataracts (inverse variance-weighted OR, 0.99; 95% CI, 0.96-1.01). Genetic risk for cataracts was associated with smaller total brain (β = -597.43 mm3; 95% CI, -1077.87 to -117.00 mm3) and gray matter (β = -375.17 mm3; 95% CI, -680.10 to -70.24 mm3) volumes, but not other brain regions. In this cohort and MR study of UK Biobank participants, cataracts were associated with increased risk of dementia, especially vascular dementia, and reduced total brain volumes. These findings lend further support to the hypothesis that cataract extraction may reduce the risk for dementia.

Causal relationship between circulating immune cells and inflammatory bowel disease: A Mendelian randomization analysis.

Inflammatory bowel disease (IBD) is an immune-mediated inflammation of the gastrointestinal tract that includes Crohn disease and ulcerative colitis (UC). Although IBD is associated with elevated levels of innate and adaptive immunity, the relationship between circulating immune cells and IBD remains largely unknown. Therefore, we conducted a bidirectional 2-sample Mendelian randomization (MR) study to determine their causal relationship. Genome-wide association study summary statistics were extracted from publicly available databases regarding immune cell phenotypes and IBD traits (including IBD, Crohn disease, and UC). MR analysis was conducted using 5 MR methods, with inverse-variance-weighted (IVW) as the primary analysis method. False discovery rate correction (FDR) was used to reduce the likelihood of type 1 errors. We also conducted MR-Egger-intercept tests to evaluate horizontal pleiotropy. After FDR adjustment of the P values for the IVW method, the results indicated no causal relationship between immune cell phenotypes and IBD or UC, but 4 immune characteristics were causally associated with Crohn disease. The percentage of human leukocyte antigen DR+ CD4+ T cells in lymphocytes was positively associated with the development of Crohn disease (odd ratio [OR], 1.13; 95% confidence interval [CI], 1.07-1.21; P < .001; PFDR = 0.019), whereas the percentage of IgD- CD27- B cells in lymphocytes (OR, 0.85; 95% CI, 0.79-0.92; P < .001; PFDR = 0.014), CD28 on CD39+ secreting CD4 regulatory T cells (OR, 0.92; 95% CI, 0.89-0.96; P < .001; PFDR = 0.019), and the percentage of naïve CD4+ T cells in all CD4+ T cells (OR, 0.90; 95% CI, 0.85-0.95; P < .001; PFDR = 0.027) were negatively related to the risk of Crohn disease. MR analysis of the above 4 immune cell phenotypes revealed no horizontal pleiotropy. In the reverse MR analysis, Crohn disease was not causally associated with any of these immune cell phenotypes. The findings provide insight into the relationship between immune cells and IBD pathogenesis, and may serve as a basis for developing novel immunotherapies.

Rheumatoid arthritis and diabetic retinopathy: A two-sample Mendelian randomization study.

Diabetic retinopathy (DR) is a common and highly blinding disease. Many clinical studies have shown a causal relationship between Rheumatoid arthritis (RA) and DR, but the results are contradictory. In addition, some clinical results and pathological inferences have certain paradoxes, and the influence of RA on the pathogenesis and development of DR Is unclear. Our research assessed the causal association between RA and the development of DR using a 2-sample Mendelian randomization method. Single nucleotide polymorphisms (SNPs) relevant to the study were extracted and filtered from genome-wide association study (GWAS) data. A DR GWAS with a sample size of 190,594 and an RA GWAS with a sample size of 58,284 were obtained. Inverse variance weighted (IVW) method was used to analyze the results, and Mendelian randomization (MR)-Egger regression method and weighted median method were used to evaluate the robustness. Sensitivity analysis was performed using pleiotropy test, heterogeneity test, leave-one-out test to ensure that the results were unbiased. Confounding factors were eliminated to ensure robustness. A total of 83 related SNPs were screened. IVW method showed a positive correlation between RA and the increased relative risk of diabetic retinopathy (OR = 1.06, 95%CI: 1.04-1.23). The same trend was shown by MR-Egger regression method and weighted median method. Sensitivity analysis showed that there was no heterogeneity in SNPs, and the results were less likely to be affected by potential bias. After removing SNPs linked to confounders, the MR results remained significant and stable in direction. There is a positive causal association between rheumatoid arthritis and diabetic retinopathy. It is important to strengthen retina-related screening and prevention in diabetic patients with RA to reduce the risk of DR In RA patients.

Integrative Metabolomics Differentiate Coronary Artery Disease, Peripheral Artery Disease, and Venous Thromboembolism Risks.

Arterial and venous cardiovascular conditions, such as coronary artery disease (CAD), peripheral artery disease (PAD), and venous thromboembolism (VTE), are genetically correlated. Interrogating underlying mechanisms may shed light on disease mechanisms. In this study, we aimed to identify (1) epidemiological and (2) causal, genetic relationships between metabolites and CAD, PAD, and VTE. We used metabolomic data from 95 402 individuals in the UK Biobank, excluding individuals with prevalent cardiovascular disease. Cox proportional-hazards models estimated the associations of 249 metabolites with incident disease. Bidirectional 2-sample Mendelian randomization (MR) estimated the causal effects between metabolites and outcomes using genome-wide association summary statistics for metabolites (n=118 466 from the UK Biobank), CAD (n=184 305 from CARDIoGRAMplusC4D 2015), PAD (n=243 060 from the Million Veterans Project), and VTE (n=650 119 from the Million Veterans Project). Multivariable MR was performed in subsequent analyses. We found that 196, 115, and 74 metabolites were associated (P<0.001) with CAD, PAD, and VTE, respectively. Further interrogation of these metabolites with MR revealed 94, 34, and 9 metabolites with potentially causal effects on CAD, PAD, and VTE, respectively. There were 21 metabolites common to CAD and PAD and 4 common to PAD and VTE. Many putatively causal metabolites included lipoprotein traits with heterogeneity across different sizes and lipid subfractions. Small VLDL (very-low-density lipoprotein) particles increased the risk for CAD while large VLDL particles decreased the risk for VTE. We identified opposing directions of CAD and PAD effects for cholesterol and triglyceride concentrations within HDLs (high-density lipoproteins). Subsequent sensitivity analyses including multivariable MR revealed several metabolites with robust, potentially causal effects of VLDL particles on CAD. While common vascular conditions are associated with overlapping metabolomic profiles, MR prioritized the role of specific lipoprotein species for potential pharmacological targets to maximize benefits in both arterial and venous beds.

The role of hypertension in the relationship between leisure screen time, physical activity and migraine: a 2-sample Mendelian randomization study

BackgroundThe relationship between lifestyle and migraine is complex, as it remains uncertain which specific lifestyle factors play the most prominent role in the development of migraine, or which modifiable metabolic traits serve as mediators in establishing causality.MethodsIndependent genetic variants strongly associated with 20 lifestyle factors were selected as instrumental variables from corresponding genome-wide association studies (GWASs). Summary-level data for migraine were obtained from the FinnGen consortium (18,477 cases and 287,837 controls) as a discovery set and the GWAS meta-analysis data (26,052 cases and 487,214 controls) as a replication set. Estimates derived from the two datasets were combined using fixed-effects meta-analysis. Two-step univariable MR (UVMR) and multivariable Mendelian randomization (MVMR) analyses were conducted to evaluate 19 potential mediators of association and determine the proportions of these mediators.ResultsThe combined effect of inverse variance weighted revealed that a one standard deviation (SD) increase in genetically predicted Leisure screen time (LST) was associated with a 27.7% increase (95% CI: 1.14–1.44) in migraine risk, while Moderate or/and vigorous physical activity (MVPA) was associated with a 26.9% decrease (95% CI: 0.61–0.87) in migraine risk. The results of the mediation analysis indicated that out of the 19 modifiable metabolic risk factors examined, hypertension explains 24.81% of the relationship between LST and the risk of experiencing migraine. Furthermore, hypertension and diastolic blood pressure (DBP) partially weaken the association between MVPA and migraines, mediating 4.86% and 4.66% respectively.ConclusionOur research findings indicated that both LST and MVPA in lifestyle have independent causal effects on migraine. Additionally, we have identified that hypertension and DBP play a mediating role in the causal pathway between these two factors and migraine.

Causal association between triglycerides and cholesterol-lowering medication with non-rheumatic valve disease: A 2-sample Mendelian randomization study.

Previous studies have found a possible causal relationship between triglycerides and lipid-lowering drugs and valvular disease. The aim of this study was to explore the potential causal relationship between triglycerides and lipid-lowering drugs and valvular disease using Mendelian randomization (MR) analysis. Data sets associated with triglycerides (441,016 participants and 12,321,875 single nucleotide polymorphisms [SNPs]) and cholesterol-lowering drugs (209,638 participants and 9851,867 SNPs) were retrieved from the Genome-Wide Association Study (GWAS) database. A total of 297 and 49 SNPs significantly associated with triglycerides and cholesterol-lowering drugs, respectively (P < 5 × 10-8), were identified. Similarly, data sets for non-rheumatic valve diseases (NVDs) (361,194 participants and 10,080,950 SNPs) were obtained from the GWAS database. Inverse variance weighting was used as the primary method for calculating the odds ratio (OR) and 95% confidence intervals (CI). The MR-Egger, weighted median, and weighted mode analyses were also used to test the robustness of the main results. The MR-Egger intercept test and the MR-PRESSO test were used to evaluate horizontal pleiotropy. Inverse variance weighted (IVW) results showed that both triglyceride and cholesterol-lowering medication were positively associated with NVDs (OR = 1.001, 95% CI 1.000-1.0012, P = 0.006; OR = 1.007, 95% CI 1.003-1.010; P = 0.002). This study suggests that both triglyceride and cholesterol-lowering medications are positively associated with NVDs, suggesting that lowering triglyceride levels or the use of cholesterol-lowering medications may reduce the incidence of NVDs. However, larger samples are required for further validation.

Identification and validation of potential genes for the diagnosis of sepsis by bioinformatics and 2-sample Mendelian randomization study.

This integrated study combines bioinformatics, machine learning, and Mendelian randomization (MR) to discover and validate molecular biomarkers for sepsis diagnosis. Methods include differential expression analysis, weighted gene co-expression network analysis (WGCNA) for identifying sepsis-related modules and hub genes, and functional enrichment analyses to explore the roles of hub genes. Machine learning algorithms identify 3 diagnostic genes - CD177, LDHA, and MCEMP1 - consistently highly expressed in sepsis patients. The nomogram model effectively predicts sepsis risk, supported by receiver operator characteristic (ROC) curves. Correlations between diagnostic genes and immune cell infiltration are observed. MR analysis reveals a positive causal relationship between MCEMP1 and sepsis risk. In conclusion, this study presents potential sepsis diagnostic biomarkers, highlighting the genetic association of MCEMP1 with sepsis for insights into early diagnosis.

Insights into inflammation and implications for the pathogenesis and long-term outcomes of endometrial cancer: genome-wide surveys and a clinical cohort study

BackgroundDespite evidence showing a connection between inflammation and endometrial cancer (EC) risk, the surveys on genetic correlation and cohort studies investigating the impact on long-term outcomes have yet to be refined. We aimed to address the impact of inflammation factors on the pathogenesis, progression and consequences of EC.MethodsFor the genetic correlation analyses, a two-sample of Mendelian randomization (MR) study was applied to investigate inflammation-related single-nucleotide polymorphisms involved with endometrial cancer from GWAS databases. The observational retrospective study included consecutive patients diagnosed with EC (stage I to IV) with surgeries between January 2010 and October 2020 at the Cancer Hospital of Shantou University Medical College.ResultsThe 2-sample MR surveys indicated no causal relationship between inflammatory cytokines and endometrial cancer. 780 cases (median age, 55.0 years ) diagnosed with EC were included in the cohort and followed up for an average of 6.8 years. Increased inflammatory parameters at baseline were associated with a higher FIGO stage and invasive EC risk (odds ratios [OR] 1.01 to 4.20). Multivariate-cox regression suggested that multiple inflammatory indicators were significantly associated with overall survival (OS) and progression-free survival (PFS) (P < 0.05). Nomogram models based on inflammatory risk and clinical factors were developed for OS and PFS with C-index of 0.811 and 0.789, respectively. LASSO regression for the validation supported the predictive efficacy of inflammatory and clinical factors on the long-term outcomes of EC.ConclusionsDespite the fact that the genetic surveys did not show a detrimental impact of inflammatory cytokines on the endometrial cancer risk, our cohort study suggested that inflammatory level was associated with the progression and long-term outcomes of EC. This evidence may contribute to new strategies targeted at decreasing inflammation levels during EC therapy.

The Potential Role of Female Sex Hormones in Patients With Inflammatory Bowel Disease: A 2-Sample Mendelian Randomization Study.

An association between female sex hormones and inflammatory bowel disease (IBD) has been reported in epidemiological studies. However, a solid causal relationship has not been established. Therefore, we performed a 2-sample Mendelian randomization (MR) study to explore the causal association between genetically predicted female sex hormone exposure, especially estrogen, and IBD. Genetic variants for female sex hormone exposure (ovulatory function, reproductive function, oral contraceptive pills, and hormone replacement therapy) were obtained from genome-wide association studies. Summary statistics for IBD were derived from the International Inflammatory Bowel Disease Genetics Consortium. We applied inverse variance weighted (IVW), MR-Egger, and weighted median (WM) methods in this MR study. Heterogeneity, horizontal pleiotropy, and sensitivity analyses were conducted to confirm the accuracy and robustness of our results. Our study found that genetically predicted age at menarche was associated with an increased risk of Crohn's disease (odds ratio [OR] IVW 1.235, 95% confidence interval [CI] 1.028-1.484, P = 0.024), genetically predicted age of the last used hormone replacement therapy was associated with an increased risk of ulcerative colitis (OR WM 1.636, 95% CI 1.011-2.648, P = 0.045), and genetically predicted number of live births was related to a decreased risk of Crohn's disease (OR IVW 0.583, 95% CI 0.373-0.912, P = 0.018). This study provided evidence for a link between female sex hormone exposure, especially estrogen, and IBD. Further investigations are needed to explore the causal effect of estrogen on IBD activity and the underlying mechanism of estrogen in IBD.

Causal relationship between inflammatory markers and left ventricle geometry and function: A 2-sample Mendelian randomization study.

Studies have shown that some inflammatory markers can predict the risk of cardiovascular disease (CVD) and affect the structure and function of the heart. However, a causal relationship between inflammatory markers and the cardiac structure and function has not yet been established. Thus, we conducted a 2-sample Mendelian randomization (MR) study to explore the potential causal relationship between inflammatory markers and prognostically-related left ventricular (LV) parameters. Instrumental variables (IVs) for C-reactive protein (CRP), interleukin-6 (IL-6), and myeloperoxidase (MPO) levels were selected from the databases of large genome-wide association studies (GWAS). Summary statistics for LV parameters, including LV mass, ejection fraction, end-diastolic and systolic volumes, and the ratio of LV mass to end-diastolic volume, were obtained from cardiovascular magnetic resonance studies of the UK Biobank (n = 16923). The inverse-variance weighted (IVW) method was the primary analytical method used, and was complemented with the MR-Egger, weighted median, simple mode, weighted mode, and MR pleiotropy residual sum and outlier (MR-PRESSO) methods. Sensitivity analysis was performed to evaluate the robustness of the results. CRP was significantly associated with the LV mass in the IVW method (β = -0.13 g [95% confidence interval [CI], 0.78 g-1.00 g], P = .046). A higher standard deviation of genetically-predicted CRP levels was associated with a 0.13 ± 0.06 g lower LV mass. No causal relationships of IL-6 and MPO with LV parameters were found. No evidence of heterogeneity and pleiotropy was detected. Sensitivity analyses confirmed the robustness of the results. Two-sample MR analysis revealed a causal association between increased CRP level and decreased LV mass, whereas IL-6 and MPO levels did not influence the LV parameters. However, further research is required to validate our findings.

Association between serum total cholesterol and the development of gastric cancer: A two-way two-sample Mendelian randomization study.

Previous epidemiologic studies have suggested a potential negative correlation between total cholesterol (TC) and Gastric cancer (GC); however, several observational studies have shown conflicting results and have failed to provide definitive evidence for a causal relationship between TC and GC. Therefore, we conducted a 2-sample bidirectional Mendelian randomization (MR) study to explore the genetic correlation and potential causal relationship between the 2 variables. We screened for single nucleotide polymorphisms (SNPs) associated with TC and GC utilizing a large-scale genome-wide association study (GWAS) public database. The causal relationship was analyzed using 5 MR analysis methods: inverse variance weighting (IVW), weighted median, MR-Egger regression, weighted mode, and simple mode. Additionally, reverse MR analysis was performed to evaluate the possibility of reverse causality. Sensitivity analyses were conducted, including heterogeneity tests, horizontal multiple validity tests, and leave-one-out tests. After meticulous screening, 79 SNPs were identified as instrumental variables (IVs). The IVW method revealed a causal relationship between TC and GC (OR = 0.844; 95% CI: 0.741-0.961; P = .01). Sensitivity analyses did not detect significant horizontal pleiotropy. Though heterogeneity was observed in the forward MR analysis (IVW, Qp = 0.0006), the results remained reliable as we utilized the IVW random-effects model as the primary analytical method. Furthermore, inverse MR analysis found no evidence of reverse causality between TC and GC, effectively ruling out the influence of GC on the reverse causality of TC. Our MR study provided evidence of a causal association between TC and GC, suggesting that TC acts as a protective factor against GC due to its negative association with the disease.

The causal relationship of depression, anxiety, and neuroticism with endometriosis: A bidirectional 2-sample Mendelian randomization study.

Endometriosis, identified by the abnormal growth of endometrial cells beyond the inner lining of the uterus, often manifests through symptoms like painful menstruation and challenges in conceiving. Observational studies suggest that endometriosis is often comorbid with mental disorders, including anxiety and depression. The nature of these connections, whether they are causal, is still debated and calls for further empirical evidence. We utilized a bidirectional 2-sample Mendelian randomization (MR) approach, harnessing genome-wide association study data to explore the connections among depression, anxiety, neuroticism, and endometriosis. To scrutinize the causative connections between mental health issues and endometriosis, Inverse Variance Weighting (IVW) was employed as the primary analytical tool, complemented by Weighted Median Estimation, Simple mode, Weighted mode, and MR-Egger regression for additional analysis. To examine the potential for reverse causation, reverse MR was applied. To strengthen the reliability of our findings, we carried out sensitivity analyses that included heterogeneity tests, tests for pleiotropy, and leave-one-out analyses. The IVW analysis revealed a significant correlation between the genetic inclination towards depression and a heightened risk of developing endometriosis [Odds Ratio (OR) = 1.151, 95% Confidence Interval (CI) = 1.025-1.293, P = .017]. Similarly, a genetic predisposition to neuroticism was significantly associated with an increased risk of endometriosis (OR = 1.128, 95% CI = 1.038-1.226, P = .004). However, no causative link was found between genetic susceptibility to anxiety and the occurrence of endometriosis. Reverse MR analysis did not support a bidirectional genetic susceptibility between endometriosis and psychiatric disorders. The MR analysis presents genetic data supporting the notion that depression and neuroticism are risk factors for endometriosis. Conversely, it found no evidence of a causal connection between anxiety and the development of endometriosis. Enhancing mental health treatment should be considered a preventive measure against endometriosis.