Two-sample Mendelian Randomization Analysis Research Articles

No genetic association between sleep traits and periodontitis: A bidirectional two-sample Mendelian randomization study

ABSTRACT Objective This study aimed to investigate the potential genetic link between sleep traits and periodontitis. Methods A two-sample bidirectional Mendelian randomization (MR) analysis was conducted using publicly available genome-wide association studies data on chronotype, daytime sleepiness, daytime napping frequency, insomnia, sleep duration, snoring, and the apnea-hypopnea index (AHI), along with a separate dataset on periodontitis. Results Chronotype (OR = 0.929, 95% CI = 0.788–1.095), daytime sleepiness (OR = 0.492, 95% CI = 0.186–1.306), daytime napping frequency (OR = 1.178, 95% CI = 0.745–1.863), sleep duration (OR = 0.868, 95% CI = 0.644–1.169), AHI (OR = 1.124, 95% CI = 0.980–1.289), insomnia (OR = 0.832, 95% CI = 0.440–1.573), and snoring (OR = 0.641, 95% CI = 0.198–2.075) had no effect on periodontitis. Similarly, periodontitis demonstrated no significant effect on sleep traits. Conclusions There is no evidence of a bidirectional genetic relationship between sleep traits and the risk of periodontitis.

No causal relationship between serum vitamin D levels and alcoholic liver disease: a two-sample bidirectional Mendelian randomization study.

Numerous observational studies have presented an association between Vitamin D (VD) and Alcoholic Liver Disease (ALD). However, sufficient evidence from Randomized Controlled Trials (RCTs) substantiating this correlation is scarce, thus leaving the causality of this relationship ambiguous. To overcome the shortcomings of traditional observational studies, we performed a two-sample bidirectional Mendelian randomization (MR) analysis to ascertain the causal relationship between VD and ALD. We utilized summary statistics datasets from Genome-Wide Association Studies (GWAS) for VD and ALD. We selected genetic instruments that measure circulating VD levels (n = 64,979), and retrieved ALD statistics from GWASs, inclusive of 1,416 cases and 217,376 healthy controls, while excluding chronic liver diseases such as nonalcoholic fatty liver disease, toxic liver disease, and viral hepatitis. Subsequent, MR analyses were performed to obtain effect estimates using inverse variance weighted (IVW) random effect models. Cochran's Q statistic and MR-Egger regression intercept analyses were used to assess pleiotropy. Sensitivity analyses using the MR Egger, weighted median, simple mode, and weighted mode methods were also performed. Leave-one-out analysis was used to identify SNPs with potential effect. Reverse MR analysis was also performed. In IVW, our MR analysis incorporated 21 independent SNPs, circulating VD levels had no causal effect on ALD [OR = 0.624 (0.336-1.160), p = 0.136] and ALD had no causal effect on circulating VD [OR = 0.997 (0.986-1.008), p = 0.555]. No heterogeneity or pleiotropy was observed (p > 0.05). Other MR methods also agreed with IVW results. This study provides the causal relationship between genetically predicted circulating Vitamin D levels and ALD and provides new insights into the genetics of ALD.

Rheumatoid arthritis and adverse pregnancy outcomes: a bidirectional two-sample mendelian randomization study

BackgroundThere is growing evidence of bidirectional associations between rheumatoid arthritis and adverse pregnancy outcomes (APOs) in observational studies, but little is known about the causal direction of these associations. Therefore, we explored the potential causal relationships between rheumatoid arthritis and APOs using a bidirectional two-sample Mendelian randomization (MR) in European and Asian populations.MethodsWe conducted a bidirectional two-sample Mendelian randomization analysis using available summary statistics from released genome-wide association studies. Summary statistics for instrument–outcome associations were retrieved from two separate databases for rheumatoid arthritis and adverse pregnancy outcomes, respectively. The inverse-variance weighted method was used as the primary MR analysis, and cML-MA-BIC was used as the supplementary analysis. MR-Egger, MR pleiotropy residual sum and outlier (MR-PRESSO), and Cochran Q statistic method were implemented as sensitivity analyses approach to ensure the robustness of the results.ResultsOur study showed that a higher risk of rheumatoid arthritis in the European population was associated with gestational hypertension (OR: 1.04, 95%CI: 1.02–1.06), pre-eclampsia (OR: 1.06, 95%CI: 1.01–1.11), fetal growth restriction (OR: 1.08, 95%CI: 1.04–1.12), preterm delivery (OR:1.04, 95%CI: 1.01–1.07). Furthermore, we found no evidence that APOs had causal effects on rheumatoid arthritis in the reverse MR analysis. No association between rheumatoid arthritis and APOs was found in East Asian population. There was no heterogeneity or horizontal pleiotropy.ConclusionsThis MR analysis provides the positive causal association from rheumatoid arthritis to gestational hypertension, pre-eclampsia, fetal growth restriction and preterm delivery genetically. It highlights the importance of more intensive prenatal care and early intervention among pregnant women with rheumatoid arthritis to prevent potential adverse obstetric outcomes.

The plasma lipids with different fatty acid chains are associated with the risk of hemorrhagic stroke: a Mendelian randomization study.

Hemorrhagic stroke, characterized by acute bleeding due to cerebrovascular lesions, is associated with plasma lipids and endothelial damage. The causal relationship between genetic plasma lipid levels and hemorrhagic stroke remains unclear. This study employs a two-sample Mendelian randomization (MR) analysis to explore the causal relationship between plasma lipid profiles with different fatty acid chains and the risk of intracerebral and subarachnoid hemorrhage, the two main subtypes of hemorrhagic stroke. The datasets for exposure and outcome summary statistics were obtained from publicly available sources such as the GWAS Catalog, IEU OpenGWAS project, and FinnGen. The two-sample MR analysis was employed to initially assess the causal relationship between 179 plasma lipid species and the risk of intracerebral and subarachnoid hemorrhage in the Finnish population, leading to the identification of candidate lipids. The same methods were applied to reanalyze data from European populations and conduct a meta-analysis of the candidate lipids. The Inverse Variance Weighting (IVW) method served as the primary analysis for causal inference, with additional methods used for complementary analyses. Sensitivity analysis was conducted to clarify causal relationships and reduce biases. Two analyses using Mendelian randomization were performed, followed by meta-analyses of the results. A causal relationship was established between 11 specific lipid species and the occurrence of intracerebral hemorrhage within the European population. Additionally, 5 distinct lipid species were associated with subarachnoid hemorrhage. Predominantly, lipids with linoleic acid and arachidonic acid side chains were identified. Notably, lipids containing arachidonic acid chains (C20:4) such as PC 18:1;0_20:4;0 consistently showed a decreased risk of both intracerebral hemorrhage [p < 0.001; OR(95% CI) = 0.892(0.835-0.954)] and subarachnoid hemorrhage [p = 0.002; OR(95% CI) = 0.794(0.689-0.916)]. Conversely, lipids with linoleic acid chains (C18:2) were associated with an increased risk of intracerebral hemorrhage. This study identifies a potential causal relationship between lipids with different fatty acid side chains and the risk of intracerebral and subarachnoid hemorrhagic stroke, improving the understanding of the mechanisms behind the onset and progression of hemorrhagic stroke.

Causal effects of risky behaviours on heart failure: a two-sample Mendelian randomisation study.

Aims/Background Previous studies have indicated correlations between various risky behaviours, increased risk tolerance, and the likelihood of heart failure. However, the causative nature of these correlations remains to be established. Therefore, our research aims to explore the causality between phenotypes of risky behaviour and the incidence of heart failure. Methods To assess causality, a two-sample Mendelian randomisation analysis was employed. Genetic variants of risky behaviours and risk tolerance (n=251,151-939,908) were sourced from existing genome-wide association summary statistics. For heart failure, genetic links were derived from a separate genome-wide association summary statistics dataset involving 977,323 individuals, comprising 47,309 heart failure cases and 930,014 controls. The primary method for this analysis was the inverse variance weighted technique. Results Mendelian randomisation analysis indicated a positive association between the number of offspring an individual has and the likelihood of heart failure (odds ratio, 1.841; 95% confidence interval, 1.528-2.217, p=1.26 × 10-10). Additionally, a modest statistically significant link was found between overall risk tolerance and heart failure (odds ratio, 1.249; 95% confidence interval, 1.003-1.556, p=0.047). Conversely, a genetic predisposition towards frequent automobile speeding showed a protective effect against heart failure (odds ratio, 0.732; 95% confidence interval, 0.545-0.982, p=0.037). Conclusion This Mendelian randomisation study confirmed genetically that risky behaviours are causally linked to the likelihood of heart failure. This finding may offer fresh perspectives on the pathogenic mechanisms underlying the progression of heart failure.

Investigating the association between gut microbiome and aortic aneurysm diseases: a bidirectional two-sample Mendelian randomization analysis.

This study aims to investigate the associations between specific bacterial taxa of the gut microbiome and the development of aortic aneurysm diseases, utilizing Mendelian Randomization (MR) to explore these associations and overcome the confounding factors commonly present in observational studies. Employing the largest available gut microbiome and aortic aneurysm Genome-Wide Association Study databases, including MiBioGen, Dutch Microbiome Project, FinnGen, UK Biobank, and Michigan Genomics Initiative, this study performs two-sample bidirectional MR analyses. Instrumental variables, linked to microbiome taxa at significant levels, were selected for identifying relationships with abdominal aortic aneurysms (AAA), thoracic aortic aneurysms (TAA), and aortic dissection (AD). Methods like inverse variance weighted, MR-PRESSO, MR-Egger, weighted median, simple mode, and mode-based estimate were used for MR analysis. Heterogeneity was assessed with the Cochran Q test. MR-Egger regression and MR-PRESSO addressed potential unbalanced horizontal pleiotropy. The analysis did not find any evidence of statistically significant associations between the gut microbiome and aortic aneurysm diseases after adjusting for the false discovery rate (FDR). Specifically, while initial results suggested correlations between 19 taxa and AAA, 25 taxa and TAA, and 13 taxa with AD, these suggested associations did not hold statistical significance post-FDR correction. Therefore, the role of individual gut microbial taxa as independent factors in the development and progression of aortic aneurysm diseases remains inconclusive. This finding underscores the necessity for larger sample sizes and more comprehensive studies to further investigate these potential links. The study emphasizes the complex relationship between the gut microbiome and aortic aneurysm diseases. Although no statistically significant associations were found after FDR correction, the findings provide valuable insights and highlight the importance of considering gut microbiota in aortic aneurysm diseases research. Understanding these interactions may eventually contribute to identifying new therapeutic and preventive strategies for aortic aneurysm diseases.

Age at first sexual intercourse, age at menarche, and age at menopause: a mendelian randomization study on lung cancer risk.

There is increasing evidence that sex hormones are involved in the development of lung cancer, but the correlation between the reproductive behavior that changes sex hormone levels and lung cancer is not yet clear. Many previous studies have investigated the association between reproductive factors and lung cancer risk, but the results have been inconsistent. Therefore, we conducted a two-sample Mendelian randomization (MR) analysis to explore the potential relationship between age at first sexual intercourse (AFS), age at menarche, and age at menopause, and lung cancer. We performed a MR analysis of the data from the genome-wide association study (GWAS) of European ancestry to evaluate the independent effects of three reproductive behaviors on lung cancer overall (LUCA), lung adenocarcinoma (LUAD), lung squamous cell carcinoma (LUSC), and small cell lung cancer (SCLC). We mainly used the inverse-variance weighting method for the MR analysis. Sensitivity was determined by a MR-pleiotropy residual sum and outlier analysis, a weighted median analysis, a MR-Egger analysis, and a leave-one-out analysis. The MR analysis results revealed that older AFS had a causal relationship with LUCA [odds ratio (OR) =0.6283, 95% confidence interval (CI): 0.4959-0.7961, P=0.0001), LUAD (OR =0.7042, 95% CI: 0.4967-0.9984, P=0.049), and LUSC (OR =0.6231, 95% CI: 0.4386-0.8853, P=0.0083). Our results revealed a causal relationship between older AFS and a lower risk of lung cancer. Our findings emphasize the importance of providing sex education, as early sexual intercourse may have undesirable effects. In addition, early psychological treatment is also essential.

Exploring the impact of electrocardiographic parameters on the risk of common arrhythmias: a two-sample Mendelian randomization study.

Observational studies have shown that heart rate (HR), heart rate variability (HRV), P-wave terminal force, P-wave duration, T-wave amplitude and PR interval are associated with risk factors for atrial fibrillation (AF) or bradycardia. Arrhythmias are associated with many causes of hospitalization. However, observational studies are susceptible to confounding factors that have not yet been identified. The objective of this study was to clarify the causal relationships by Mendelian randomization analysis. We conducted a two-sample and multivariate Mendelian randomization (MVMR) analysis using genome-wide association study (GWAS) data from a European population to assess the total and direct causal effects of HR, three HRV traits, P-wave terminal force, P-wave duration, T-wave top amplitude in five-lead modes, and the PR interval on the risk of AF (N=191,205), bradycardia (N=463,010), and supraventricular tachycardia (SVT) (N=463,010). The results of the univariate MR analysis revealed the following significant causal effects: the higher the genetically predicted PR interval, the lower the risk of AF; the higher the HR and T-wave top amplitude (aVR leads and V3 + V4 + aVL leads), the lower the risk of bradycardia; and the higher HR and the lower PR interval, the higher the risk of SVT. The multivariate MR results indicated that the HRV_standard deviation of the normal-to-normal (SDNN) interval had an independent causal effect on the risk of AF [odds ratio (OR): 0.515; 95% confidence interval (CI): 0.278-0.954; P=0.03], and the T-wave top amplitude in the aVR leads (OR: 0.998; 95% CI: 0.996-0.999; P<0.001) and the HRV_SDNN (OR: 0.988; 95% CI: 0.976-1.000; P=0.045) had independent causal effects on the risk of bradycardia. The HRV_SDNN had an independent causal effect on AF, while the HRV_SDNN and T-wave top amplitude in the aVR leads had independent causal effects on bradycardia, which suggests that some of the electrocardiographic parameters have preventive effects on the incidence of AF and bradycardia.

Association between metabolic dysfunction-associated steatotic liver disease and pulmonary function: a population-based and two-sample mendelian randomization study

BackgroundHepatic steatosis and its related complications are risk factors for multiple respiratory diseases; however, the causal relationship between metabolic dysfunction-associated steatotic liver disease (MASLD) and pulmonary function remains controversial. We aimed to identify it using a national cohort and Mendelian randomization (MR).MethodsWe enrolled 30,442 participants from the 2007 to 2012 National Health and Nutrition Examination Survey. Demographics, pulmonary function indices (forced expiratory volume in 1 s [FEV1], forced vital capacity [FVC]), and variables used to calculate the liver fat score (LFS) were collected. A two-sample MR analysis employing the summary data of genome-wide association studies on MASLD and FEV1/FVC, chronic obstructive pulmonary disease (COPD), and asthma from the Finngen Biobank and Medical Research Council Integrative Epidemiology Unit was performed.ResultsA total of 3,462 participants, 1,335 of whom had MASLD (LFS > -0.640), were finally included in the study. The FEV1 (3,204.7 vs. 3,262.5 ml, P = 0.061), FVC (4,089.1 vs. 4,143.8 ml, P = 0.146), FEV1/FVC ratio (78.5% vs. 78.8%, P = 0.233), and FEV1/predicted FEV1 ratio (146.5% vs. 141.7%, P = 0.366) were not significantly different between people with MASLD and those without. Additionally, the MR analysis suggested no causal correlation between MASLD and FEV1/FVC (P = 0.817), MASLD and COPD (P = 0.407), and MASLD and asthma (P = 0.808). Reverse MR studies showed no causal relationships yet (all P > 0.05).ConclusionOur study provides convincing evidence that there is no causal association between MASLD and pulmonary function.

Gut microbiome, and immune cells mediated effect on depression: A two-step, two-sample Mendelian randomization analysis

BackgroundThe gut microbiota (GM) plays an important role in the development of immune-related diseases, and the immune response is one of the pathomechanisms of depression (Dep); whether the effect of GM on Dep is mediated by immune cells (ImC) is unclear. ObjectiveImC may mediate the effect of GM on Dep. Our aim is to identify and quantify the role of immune characteristics as potential mediators. MethodsPooled statistics for GM (n = 7738) and ImC (n = 3757) were obtained from publicly available genome-wide association studies (GWAS), and for Dep (n = 47,696) from the Finnish database R10. We used a mediated Mendelian randomization (MR) study to investigate the causal relationship between GM and Dep and the mediating role of ImC between GM and Dep associations. ResultsThe results showed that the genetically predicted GM was significantly correlated with both ImC as well as Dep. MR analysis identified five microbiomes that had significant causal effects on Dep (Methionine biosynthesis III, PWY-6737-Starch degradation V, Parasutterella excrementihominis, Parasutterella, and Lysine biosynthesis I). In addition, five of the 26 ImC trait significantly associated with GM were most closely associated with Dep (T cell %lymphocyte、CD28-CD127-CD25++CD8br AC、CD28-CD8br AC、CD27 receptor on peripheral blood plasma cells (CD27 on PB/PC) and CD11b receptor on mononuclear myeloid-derived suppressor cells (CD11b on Mo MDSC)). This mediated MR illustrates the causal role of methionine biosynthesis III on Dep (IVW: OR = 1.08, 95%CI [1.04,1.14], P = 0.001). And there was no strong evidence for a causal effect of depression on methionine biosynthesis III. In the B cell group, the proportion of CD27 on PB/PC mediated was 7.88 %(95%CI [−0.04,0.03]) of the total effect. This study further suggests that Dep patients should actively seek immunologic intervention therapy. ConclusionThis MR study found that GM may play a causal role in Dep by mediating ImC. Our findings will help to understand the pathogenic mechanism of GM in Dep and the risk of immune mediation.

Assessing the genetic associations between plasma lipidomic profiles and psoriasis vulgaris.

Several studies have indicated a potential causal relationship between plasma standard lipids, such as high-density lipoprotein-cholesterol (HDL-C), low-density lipoprotein-cholesterol (LDL-C), triglycerides (TG), and total cholesterol (TC), and psoriasis. However, few studies have offered causal evidence of lipid species beyond these standard lipids. We conducted an analysis using a genome-wide association study (GWAS) dataset comprising 179 lipid species, including 13 types across four major categories, to identify instrumental variables (IVs) associated with plasma lipids. We utilized two GWAS datasets from the IEU and Finngen for psoriasis vulgaris as the outcome. A two-sample Mendelian randomization (MR) analysis was used to explore the causal relationship between 179 lipid species and psoriasis vulgaris in two datasets. Lipid species showing causal association in both psoriasis datasets were compared for overlap. Our study identified potential causal relationships between six lipid species and psoriasis vulgaris: phosphatidylcholine (16:1_18:2), phosphatidylcholine (18:0_18:2), phosphatidylcholine (18:1_20:4), phosphatidylethanolamine (16:0_18:2), phosphatidylinositol (18:0_20:3), and triacylglycerol (50:1). In summary, elevated plasma levels of phosphatidylcholine (16:1_18:2), phosphatidylcholine (18:0_18:2), phosphatidylethanolamine (16:0_18:2), phosphatidylinositol (18:0_20:3), and triacylglycerol (50:1) may increase the risk of psoriasis vulgaris. Conversely, plasma phosphatidylcholine (18:1_20:4) may play a protective role against psoriasis vulgaris.

Association between levels of sex hormones and risk of multiple sclerosis: a mendelian randomization study.

This research aimed to examine the causal connections between multiple sclerosis (MS) and a range of sex hormone-related traits, such as bioavailable testosterone (BT), sex hormone-binding globulin (SHBG), testosterone, and estradiol (E2). A bidirectional two-sample Mendelian randomization (MR) analysis using summary statistics from genome-wide association studies (GWAS) was conducted to investigate the relationship between sex hormone-related traits and MS. Moreover, the Inverse-variance weighted (IVW) method was employed as the primary analysis approach. The MR analysis, using the IVW method, found a significant correlation between genetically determined SHBG levels and MS (OR = 1.634, 95% CI: 1.029-2.599, p = 0.038). Similarly, the reverse MR analysis suggested a causal link between MS and SHBG (OR = 1.005, 95% CI: 1.001-1.009, P = 0.003). However, no association was observed between MS risk and E2, testosterone, or BT levels. Our MR analysis demonstrated that genetically predicted higher SHBG may be positively correlated with the risk of MS. Moreover, the role of SHBG in MS could be further investigated.

Association between inflammatory cytokines and prostate cancer

IntroductionWe conducted bidirectional two-sample Mendelian Randomization (MR) analysis to investigate the causal relationship between 91 inflammatory cytokines and prostate cancer (PCa).Material and methodsThe Inverse Variance Weighted (IVW) model served as the primary two-sample MR analysis method, utilized to estimate the causal effect of exposure on the outcome. The Weighted Median (WM) and MR Egger methods were additionally employed to complement the IVW model. Sensitivity analyses were performed using Cochran's Q test for both the IVW and MR Egger methods. To assess the presence of horizontal pleiotropy, the instrumental variables (IVs) were subjected to the MR-Egger intercept test.ResultsFollowing Bonferroni correction, the IVW analysis revealed positive correlations between PCa and the levels of C-C motif chemokine 20 (CCL20), C-C motif chemokine 23 (CCL23), fibroblast growth factor 19 (FGF19), fibroblast growth factor 23 (FGF23), and interleukin-6 (IL-6). Notably, IL-6 exhibited the strongest positive association effect (odds ratio [95% confidence interval]: 1.0076 [1.0014, 1.0139]), followed by CCL-20 (1.0067 [1.0004, 1.0129]) and FGF23 ([1.0002, 1.0119]). Reverse MR analysis indicated a negative causal relationship between PCa and interleukin-22 receptor subunit alpha-1 levels (IL22RA1) (0.4852 [0.2390, 0.9847]).ConclusionsThis study proposes that there exists a positive correlation between the levels of CCL20, CCL23, FGF19, FGF23, and IL-6 and the occurrence of PCa. Furthermore, we found evidence to support the causal relationship between decreased levels of IL22RA1 and the development of PCa. These findings unveil novel biomarkers and pathways that could potentially be targeted for the prevention and clinical treatment of PCa.

COVID-19 and the risk of acute cardiovascular diseases: a two-sample Mendelian randomization study

BackgroundEvidence suggests that coronavirus disease 2019 (COVID-19) is associated with the risk of cardiovascular diseases (CVDs). However, the results are inconsistent, and the causality remains to be established. We aimed to investigate the potential causal relationship between COVID-19 and CVDs by using two-sample Mendelian randomization (MR) analysis.MethodsSummary‐level data for COVID-19 and CVDs including myocarditis, heart failure (HF), acute myocardial infarction (AMI), arrhythmia and venous thromboembolism (VTE) were obtained from the IEU OpenGWAS project, a public genome-wide association study (GWAS). Single nucleotide polymorphisms (SNPs) were used as instrumental variables. Five complementary MR methods were performed, including inverse variance weighted (IVW), MR-Egger, weighted median, weighted mode and simple mode methods. IVW method was considered as the primary approach. Besides, sensitivity analyses, including Cochran’s Q test, MR-Egger intercept test, and leave-one-out analysis, were performed to evaluate the robustness of the results.ResultsAccording to the IVW results, our MR study indicated that genetically predicted COVID-19 was not causally connected with the risk of CVDs [myocarditis: odds ratio (OR) = 1.407, 95% confidence interval (CI) = 0.761-2.602, p-value = 0.277; HF: OR = 1.180, 95% CI = 0.980-1.420, p-value = 0.080; AMI: OR = 1.002, 95% CI = 0.998-1.005, p-value = 0.241; arrhythmia: OR = 0.865, 95% CI = 0.717-1.044, p-value = 0.132; VTE: OR = 1.013, 95% CI = 0.997-1.028, p-value = 0.115]. The supplementary MR methods showed similar results. Sensitivity analyses suggested that the causal estimates were robust.ConclusionThis two-sample MR analysis did not provide sufficient evidence for a causal relationship between COVID-19 and the risk of acute CVDs, which may provide new insights into the prevention of acute CVDs in COVID-19 patients.

Autoimmune diseases and COPD risk: A Mendelian randomization study

BackgroundStudies in epidemiology have indicated a link between chronic obstructive pulmonary disease (COPD) and various autoimmune conditions.This study aimed to investigate the potential causal link between nine autoimmune diseases with a genetic basis and COPD using a two-sample Mendelian randomization (MR) analysis. MethodTo test the impact of susceptibility to immune-related outcomes on genetic prediction of COPD risk, we used pooled statistics from the largest genome-wide association study (GWAS) in Europe in a two-sample MR setting.Genetic data for type 1 diabetes, hypothyroidism, systemic lupus erythematosus, and primary biliary cirrhosis were obtained from the European Bioinformatics Institute (EBI), while data for multiple sclerosis and primary sclerosing cholangitis were extracted from the Integrative Epidemiology Unit (IEU) database. Additionally, genetic data for ulcerative colitis, rheumatoid arthritis, and celiac disease were also collected.These nine autoimmune diseases and the COPD cohort from the UK Biobank (1605 cases and 461,328 controls) were analyzed separately as exposure and outcome.Our primary method for the initial screening was inverse variance weighting (IVW).The MR-Egger regression test assessed multivariate validity, while the Cochran’s Q test examined heterogeneity.To ensure the reliability of the findings, a leave-one-out analysis was conducted. ResultIVW discovered proof of type 1 diabetes (OR = 1.0003; 95 % CI = 1.0000–1.0005; P = 0.046), hypothyroidism (OR = 1.0004; 95 % CI = 1.0001–1.0008; P = 0.0263), celiac disease (OR = 1.0002; 95 % CI = 1.0000–1.0004; P = 0.0168) and systemic lupus erythematosus (OR = 1.0002; 95 % CI = 1.0000–1.0004; P = 0.049) were significantly linked to the heightened risk of COPD with no signs of variation or pleiotropy.Even after accounting for potential confounding factors like smoking, the correlation remained robust.Additionally, our research found that the IVW method did not indicate any causal link between COPD and multiple sclerosis, ulcerative colitis, rheumatoid arthritis, primary biliary cirrhosis, or primary sclerosing cholangitis (all P >0.05). ConclusionThis research discovered that individuals with type 1 diabetes, hypothyroidism, celiac disease, and systemic lupus erythematosus have a higher likelihood of developing COPD.Additionally, this research revealed no connection between COPD and multiple sclerosis, ulcerative colitis, rheumatoid arthritis, primary biliary cirrhosis, or primary sclerosing cholangitis.

Association between prescription opioid use and heart failure: Cohort studies and Mendelian randomization analysis

BackgroundPrescription opioid use (POU) has been shown to lead to cardiovascular disease (CVD), but its association with heart failure has not been well studied. We investigated the potential causal association between POU and HF using cohort studies and Mendelian Randomization (MR) analysis. MethodsInitially, we examined the longitudinal association between POU and HF using the data from the Health and Retirement Study (HRS) and the UK biobank. Next, we employed a two-sample MR analysis using summary statistics from genome-wide association studies (GWAS) to assess the potential causal associations between POU and HF. ResultsDuring a median of 3.8 and 13.8 years of follow-up, there were 441(8.04 per 1000 person-year) and 16,170 (3.96 per 1000 person-year) HF cases in the HRS and the UK biobank, respectively. After adjusting for covariates, participants who used prescription opioids had a 32% increased risk of developing HF, compared with non-users (HR = 1.32, 95%CI: 1.26–1.38, P < 0.001). In the MR analysis, summary statistics for POU were obtained from 78,808 UK Biobank study participants, and summary data for HF were obtained from 218,792 participants of a European population. A causal effect of genetic liability for POU on an increased risk of HF (OR = 1.16, 95% CI = 1.06, 1.27, P = 0.001) was suggested. The results were generally consistent in the sensitivity analysis, and no pleiotropy or heterogeneity were observed. ConclusionsPOU is associated with a high risk of HF. Our findings provide new insight into prescription opioid use among populations at risk of heart failure. More studies are needed to validate our results and further investigate the underlying mechanisms.

New evidence that vitamin D prevents headache: a bidirectional two-sample Mendelian randomization analysis.

Previous observational clinical studies and meta-analyses have yielded inconsistent results regarding the relationship between vitamin D and headache, and the causal relationship remains unclear. The aim of this study was to investigate the causal relationship between vitamin D and headache by bidirectional two-sample Mendelian randomisation (MR) analysis. The relationship between high levels of vitamin D and headache was investigated by two-sample MR analysis using publicly available genome-wide association study (GWAS) data. The primary method was inverse variance weighting (IVW), and secondary methods were weighted median and MR-Egger methods. No heterogeneity or horizontal multidirectionality was found in the MR results. The robustness and validity of the findings were assessed using the leave-behind method. A significant causal relationship was found between high vitamin D levels and headache using the IVW method (OR = 0.848; p = 0.007; 95% CI = 0.752-0.956). However, in a reverse analysis, no evidence of a causal relationship between headache and high levels of vitamin D was found using the IVW method (OR = 1.001; p = 0.906; 95% CI = 0.994-1.006). Our MR analyses showed no significant horizontal multidimensionality or heterogeneity (p > 0.05). Sensitivity analyses confirmed that MR estimates were not affected by single nucleotide polymorphisms (SNPs). Confirmation that our results are robust and valid has been obtained by the leave-one-out method. Our study suggests that high levels of vitamin D prevent the risk of headache. However, there is no evidence of a causal relationship between headache and high levels of vitamin D. Vitamin D may reduce the risk of headache.

Causal relationship between rheumatoid arthritis and ankylosing spondylitis: Two-sample Mendelian randomization.

To investigate the causal relationship between rheumatoid arthritis (RA) and ankylosing spondylitis using Mendelian randomization (MR). Genetic loci independently associated with RA and ankylosing spondylitis in people of European origin were selected as instrumental variables using pooled data from large-scale genome-wide association studies. Three MR analyses, MR-Egger, weighted median, and inverse variance weighting, were used to investigate the causal relationship between RA and ankylosing spondylitis. Heterogeneity and multiplicity tests were used, and a sensitivity test using the "leave-one-out" method was used to explore the robustness of the results. The inverse variance weighting results showed an OR (95 % CI) of 1.25 (1.11-1.41), P < .001, indicating a causal relationship between RA and ankylosing spondylitis. And no heterogeneity and pleiotropy were found by the test and sensitivity analysis also showed robust results. The present study was conducted to analyze and explore the genetic data using two-sample MR analysis and the results showed that there is a causal relationship between RA and the occurrence of ankylosing spondylitis.

The integrity of the corticospinal tract and corpus callosum, and the risk of ALS: univariable and multivariable Mendelian randomization

Studies suggest that amyotrophic lateral sclerosis (ALS) compromises the integrity of white matter fiber tracts, primarily affecting motor fibers. However, it remains uncertain whether the integrity of these fibers influences the risk of ALS. We performed bidirectional two-sample Mendelian randomization (MR) and multivariable MR analyses to evaluate the associative relationships between the integrity of fiber tracts [including the corticospinal tract (CST) and corpus callosum (CC)] and the risk of ALS. Genetic instrumental variables for specific fiber tracts were obtained from published genome-wide association studies (GWASs), including 33,292 European individuals from five diffusion magnetic resonance imaging (dMRI) datasets. Summary-level GWAS data for ALS were derived from 27,205 ALS patients and 110,881 controls. The MR results suggested that an increase in the first principal component (PC1) of fractional anisotropy (FA) in the genu of the CC (GCC) was correlated with an increased risk of ALS (PFDR = 0.001, odds ratio = 1.363, 95% confidence interval 1.178–1.577). Although other neuroimaging phenotypes [mean diffusivity in the CST, radial diffusivity (RD) in the CST, FA in the GCC, PC1 in the body of the CC (BCC), PC1 in the CST, and RD in the GCC] did not pass correction, they were also considered to have suggestive associations with the risk of ALS. No evidence revealed that ALS caused changes in the integrity of fiber tracts. In summary, the results of this study provide genetic support for the potential association between the integrity of specific fiber tracts and the risk of ALS. Greater fiber integrity in the GCC and BCC may be a risk factor for ALS, while greater fiber integrity in the CST may have a protective effect on ALS. This study provides insights into ALS development.

The interplay between cytokines and stroke: a bi-directional Mendelian randomization study

Stroke, the second leading cause of death and disability, causes massive cell death in the brain followed by secondary inflammatory injury initiated by disease associated molecular patterns released from dead cells. Nonetheless, the evidence regarding the causal relationship between inflammatory cytokines and stroke subtypes is obscure. To leverage large scale genetic association data to investigate the interplay between circulating cytokines and stroke, we adopted a two-sample bi-directional Mendelian randomization (MR) analysis. Firstly, we performed a forward MR analysis to examine the associations of genetically determined 31 cytokines with 6 stroke subtypes. Secondly, we conducted a reverse MR analysis to check the associations of 6 stroke subtypes with 31 cytokines. In the forward MR analysis, genetic evidence suggests that 21 cytokines were significantly associated with certain stroke subtype risk with |β| ranging from 1.90 × 10−4 to 0.74. In the reverse MR analysis, our results found that five stroke subtypes (intracerebral hemorrhage (ICH), large artery atherosclerosis ischemic stroke (LAAS), lacunar stroke (LS), cardioembolic ischemic stroke (CEI), small-vessel ischemic stroke (SV)) caused significantly changes in 16 cytokines with |β| ranging from 1.08 × 10−4 to 0.69. In particular, those five stroke subtypes were statistically significantly associated with C-reactive protein (CRP). In addition, ICH, LAAS, LS and SV were significantly correlated with vascular endothelial growth factor (VEGF), while LAAS, LS, CEI and SV were significantly related to fibroblast growth factor (FGF). Moreover, integrated bi-directional MR analysis, these factors (IL-3Rα, IL-6R, IL-6Rα, IL-1Ra, insulin-like growth factor-1(IGF-1), IL-12Rβ2) can be used as predictors of some specific stroke subtypes. As well as, IL-16 and C–C motif chemokine receptor 7 (CCR7) can be used as prognostic factors of stroke. Our findings prognostic identify potential pharmacological opportunities, including perturbation of circulating cytokines for both predicting stroke risk and post stroke treatment effects. As we conducted a comprehensive search and analysis of stroke subtype and cytokines in the existing publicly available GWAS database, the results have good population-generalizability.