Two-sample Mendelian Randomization Analysis Research Articles

Causal relationships between leukocyte telomere length and female reproductive system diseases: A bidirectional Mendelian randomization study

Objective: Although numerous observational studies have revealed a correlation between leukocyte telomere length (LTL) and female reproductive system diseases (RSDs), the findings of these studies have tended to be consistent. In this study, we accordingly sought to clarify the causal relationships between LTL and RSDs. Methods: We performed a bidirectional two-sample Mendelian randomization (MR) analysis using pooled statistics from genome-wide association studies of LTL and nine female RSDs. The final results were analyzed using five MR methods, with the inverse variance weighted (IVW) method used as the primary outcome. We applied MR-PRESSO to exclude outliers. Sensitivity analyses were also conducted to assess heterogeneity and pleiotropy. Results: In the forward MR analysis, a genetic prediction of longer LTLs was found to be causally associated with higher risks of endometriosis (IVW: OR = 1.25, 95%CI: 1.06–1.46, P = 0.008), leiomyoma of the uterus (IVW: OR = 1.73, 95%: 1.52–1.98, P = 4.9E-16) and ovarian cysts (IVW: OR = 1.31, 95%:1.19–1.45, P = 1.5E-07). In the reverse MR results, female RSDs were shown to have no significant effect on LTLs (all P-values > 0.05). Sensitivity analysis confirmed the robustness of these results. Conclusions: Our findings substantiate the assumption that a genetically predicted longer LTL elevates the risk of endometriosis, leiomyoma of the uterus, and ovarian cysts, with no influence of RSDs on LTL. These findings contribute to establishing a causal link between LTL and RSDs, overcoming the constraints of earlier observational studies. They also imply that LTL could potentially serve as a biomarker for the occurrence of endometriosis, leiomyoma of the uterus, and ovarian cysts.

Type 2 diabetes mellitus has a positive role in osteomyelitis: A Mendelian randomization analysis.

According to clinical evidence, type 2 diabetes mellitus (T2D) and osteomyelitis (OM) are currently the 2 major causes of mortality and morbidity in humans. Despite accounts of their coexistence, there is still no understanding of their fundamental connection. We attempted to assess the causal effect of T2D on OM using the two-sample Mendelian randomization method. The whole gene-wide association study's aggregate data were examined. Single-nucleotide polymorphisms, which have a substantial correlation with T2D, were used as instrumental variables in a two-sample Mendelian randomization (MR) analysis to assess the causal relationship between T2D and OM risk using the inverse variance weighting, MR-egger regression, and weighted median approaches, respectively. A total of 114 single-nucleotide polymorphism were used as instrumental variables in this analysis. The inverse variance-weighted analysis showed a significant causal relationship between T2D and OM, indicating that T2D has a detrimental effect on OM risk. The odds ratio for the causal effect of T2D on OM was 1.317, with a 95% confidence interval of (1.140, 1.522) (P < .001). To assess heterogeneity, Cochran Q test statistics and MR-Egger regression were applied in the inverse variance-weighted technique. The P-value of .737 indicated a considerable level of heterogeneity was not absent in the data. This study used Mendelian randomization analysis to establish a causal relationship between T2D and OM. The findings suggest that T2D may increase the risk of OM.

Causal effects of cardiovascular health on five epigenetic clocks

BackgroundThis work delves into the relationship between cardiovascular health (CVH) and aging. Previous studies have shown an association of ideal CVH with a slower aging rate, measured by epigenetic age acceleration (EAA). However, the causal relationship between CVH and EAA has remained unexplored.Methods and resultsWe performed genome-wide association studies (GWAS) on the (12-point) CVH score and its components using the Taiwan Biobank data, in which weighted genetic risk scores were treated as instrumental variables. Subsequently, we conducted a one-sample Mendelian Randomization (MR) analysis with the two-stage least-squares method on 2383 participants to examine the causal relationship between the (12-point) CVH score and EAA. As a result, we observed a significant causal effect of the CVH score on GrimAge acceleration (GrimEAA) (β [SE]: − 0.993 [0.363] year; p = 0.0063) and DNA methylation-based plasminogen activator inhibitor-1 (DNAmPAI-1) (β [SE]: − 0.294 [0.099] standard deviation (sd) of DNAmPAI-1; p = 0.0030). Digging individual CVH components in depth, the ideal total cholesterol score (0 [poor], 1 [intermediate], or 2 [ideal]) was causally associated with DNAmPAI-1 (β [SE]: − 0.452 [0.150] sd of DNAmPAI-1; false discovery rate [FDR] q = 0.0102). The ideal body mass index (BMI) score was causally associated with GrimEAA (β [SE]: − 2.382 [0.952] years; FDR q = 0.0498) and DunedinPACE (β [SE]: − 0.097 [0.030]; FDR q = 0.0044). We also performed a two-sample MR analysis using the summary statistics from European GWAS. We observed that the (12-point) CVH score exhibits a significant causal effect on Horvath’s intrinsic epigenetic age acceleration (β [SE]: − 0.389 [0.186] years; p = 0.036) and GrimEAA (β [SE]: − 0.526 [0.244] years; p = 0.031). Furthermore, we detected causal effects of BMI (β [SE]: 0.599 [0.081] years; q = 2.91E-12), never smoking (β [SE]: − 2.981 [0.524] years; q = 1.63E-7), walking (β [SE]: − 4.313 [1.236] years; q = 0.004), and dried fruit intake (β [SE]: − 1.523 [0.504] years; q = 0.013) on GrimEAA in the European population.ConclusionsOur research confirms the causal link between maintaining an ideal CVH and epigenetic age. It provides a tangible pathway for individuals to improve their health and potentially slow aging.

Thyroid function, physical activity and sedentary behaviour: A bidirectional two-sample Mendelian randomisation study.

The interinfluence of thyroid function and daily physical activity (PA) remains unclear. We examined the causal relationship between genetically proxied thyroid-related traits; hypothyroidism, hyperthyroidism, thyroid stimulating hormone (TSH) and free thyroxine (FT4), and daily PA measures; leisure screen time (LST) and moderate-to-vigorous physical activity (MVPA), using Mendelian randomisation (MR) analysis. We used genome-wide association study (GWAS) data from the ThyroidOmics Consortium and the most comprehensive meta-analysis on PA, comprising data on hypothyroidism (n = 53 423), hyperthyroidism (n = 51 823), TSH within the reference range (n = 54 288), fT4 within the reference range (n = 49 269), LST (n = 526 725), and MVPA (n = 608 595) to conduct a bidirectional two-sample MR analysis. The inverse variance weighted (IVW) method was employed as the primary result. Sensitivity analyses included MR-Egger, weighted median, and MR pleiotropy residual sum and outlier (MR-PRESSO) regression. Similar investigations were conducted in the reverse direction. Finally, we analysed a multivariable MR using body mass index (BMI)-related traits GWAS data. In the primary IVW analysis, an increase in genetically proxied TSH levels significantly increased LST (correlation coefficient (β) = 0.040; 95% confidence interval (CI) = 0.020-0.061, P = 9.776 × 10-5). The multivariable MR analysis indicated that the positive causal effect still existed when considering the influence of BMI (MVMR-IVW: β = 0.042; 95% CI = 0.011-0.073, P = 0.007). Conversely, there was no evidence to suggest that PA impacts thyroid function. The results of this MR analysis suggest that thyroid function influences daily PA. The positive association between TSH and LST is not confounded or mediated by BMI.

Exploration of potential drug targets for Glaucoma by plasma proteome screening

BackgroundGlaucoma is the leading cause of irreversible blindness. However, the current available treatment methods are still unsatisfactory. Therefore, the exploration of new drug targets for the treatment of glaucoma is of paramount importance. MethodsWe conducted two-sample Mendelian randomization (MR) using plasma protein quantitative trait loci (pQTL) data from two datasets (n = 734, n = 4907) and their instrumental variables to investigate the causal relationship between plasma proteins and glaucoma. The analysis was validated by replacing the exposure and outcome cohorts. Additionally, we utilized protein-protein interaction networks to assess the associations between these potential drug targets and existing drug targets. ResultsThrough two-sample Mendelian randomization analysis, we identified causal relationships between Glaucoma and the following proteins: AZU1, OBP2B, ENPP5, INPP5B, KREMEN1, LYPLAL1, and PTPRJ. External validation confirmed the protective effect of LYPLAL1 on Glaucoma, while ENPP5, KREMEN1, and PTPRJ increased the risk of Glaucoma. Reverse MR and Steiger filtering did not indicate any reverse causal associations of the aforementioned proteins with Glaucoma. ConclusionOur study demonstrates a causal impact of ENPP5, KREMEN1, PTPRJ, and LYPLAL1 on the risk of Glaucoma. These findings suggest that these four proteins may serve as promising drug targets for Glaucoma treatment. SignificanceCurrently, the pharmacological treatment of glaucoma primarily focuses on lowering intraocular pressure, which has its limitations. Targeted therapy is a personalized treatment approach that aims to inhibit or block the development and progression of diseases such as cancer and inflammation by selectively acting on specific biomolecules or signaling pathways. Our research employs a two-sample Mendelian randomization (MR) method, integrating a large amount of GWAS and pQTL data to perform MR analysis. This has enabled us to explore several plasma proteins as potential drug targets for glaucoma, providing direction and a research foundation for future investigations into glaucoma drug targets.

Association of air pollutants with psychiatric disorders: a two-sample Mendelian randomization

BackgroundThe link between air pollution and increased risk of psychiatric disorders has been growing in evidence. However, the causal relationship between air pollution and psychiatric disorders remains poorly understood. MethodsSingle-nucleotide polymorphisms associated with air pollutants (including NOx, NO2, PM2.5, PM2.5–10, and PM10) from the UK Biobank were used as instrumental variables. Summary-level data for psychiatric disorders (major depressive disorder, anxiety, bipolar disorder, schizophrenia, post-traumatic stress disorder, attention deficit hyperactivity disorder, autism spectrum disorder, anorexia nervosa, and obsessive-compulsive disorder) were procured from the Psychiatric Genomics Consortium and FinnGen consortium. Two-sample Mendelian randomization (MR) analysis was conducted to analyze the causal associations. ResultsThe MR analysis revealed significant associations between certain air pollutants and specific types of psychiatric disorders. The inverse-variance weighted model of preliminary analysis indicated that genetically predicted NO2 was associated with increased risks of major depressive disorder (odds ratio [OR]: 1.13, 95 % confidence intervals [CI]: 1.00–1.28, P = 0.041), bipolar disorder (OR: 1.26, 95 % CI: 1.00–1.58, P = 0.0497), schizophrenia (OR: 1.57, 95 % CI: 1.23–2.00, P < 0.001), attention deficit hyperactivity disorder (OR: 1.61, 95 % CI: 1.25–2.09, P < 0.001) and autism spectrum disorder (OR: 1.39, 95 % CI: 1.01–1.91, P = 0.044). Genetically predicted PM2.5 showed a positive association with the risk of major depressive disorder (OR: 1.21, 95 % CI: 1.06–1.39, P = 0.006), bipolar disorder (OR: 1.32, 95 % CI: 1.03–1.69, P = 0.030) and attention deficit hyperactivity disorder (OR: 1.57, 95 % CI: 1.16–2.12, P = 0.004). In addition, our results also indicated that NOx (OR: 1.64, 95 % CI: 1.21–2.21, P = 0.0012) and PM10 (OR: 1.70, 95 % CI: 1.23–2.36, P = 0.0014) could increase the risk of attention deficit hyperactivity disorder. ConclusionsThe MR analysis provides evidence for the causality of different air pollutants on specific psychiatric disorders, underscoring the importance of mitigating air pollution to reduce the risk of psychiatric disorders.

Aspirin may be more suitable for patients with major depression: Evidence from two-sample Mendelian randomization analysis.

Utilizing two-sample Mendelian randomization (TSMR) analysis, this study aims to explore the potential bidirectional causal relationship between common nonsteroidal anti-inflammatory drugs (paracetamol, ibuprofen, aspirin) and major depression (MD) from a genetic standpoint. We employed summarized data from a Genome-Wide Association Study (GWAS) of European populations. The inverse variance weighted (IVW) method was used for TSMR analysis; outcomes were evaluated based on p-value, OR (Odds Ratio), and 95% confidence interval (95% CI). From a genetic perspective, the study found that the use of paracetamol and ibuprofen increased the risk of MD (IVW (MRE): OR = 2.314, 95% CI: 1.609-3.327; p = 6.07E-06) and (IVW (MRE): OR = 2.308, 95% CI: 1.780-3.653; p = 0.002), respectively. No significant causal relationship was found between aspirin and MD (p > 0.05). Reverse TSMR analysis found that MD increased the genetic predisposition to use paracetamol, ibuprofen, and aspirin (IVW (MRE): OR = 1.042, 95% CI: 1.030-1.054, p = 3.07E-12), (IVW (FE): OR = 1.015, 95% CI: 1.007-1.023, p = 1.13E-04), (IVW (MRE): OR = 1.019, 95% CI: 1.009-1.030, p = 4.22E-04), respectively. Other analytical methods and sensitivity analyses further supported the robustness and reliability of these findings. This study provides preliminary genetic evidence through bidirectional TSMR analysis that MD increases the genetic predisposition to use paracetamol, ibuprofen, and aspirin, aiding clinicians in devising preventive strategies against the misuse of non-steroidal anti-inflammatory drugs. Moreover, we found that the use of paracetamol and ibuprofen increases the risk of MD, whereas aspirin did not. This suggests a crucial clinical implication: clinicians treating MD patients could opt for the relatively safer aspirin over paracetamol and ibuprofen.

Metabolite, immunocyte phenotype, and lymphoma: a Mendelian randomization study.

Recent studies have confirmed that metabolites and immunocyte phenotype may be associated with the risk of lymphoma. However, the bidirectional causality between metabolites, immunocyte phenotype, disease risk, and whether immunity is an intermediate mediator between metabolism and lymphoma causality is still unclear. To elucidate the causal relationship between metabolites, immune cell phenotypes, and lymphomas, we used two-sample Mendelian randomization (MR) and two-step MR analysis. Applying large-scale genome-wide association studies (GWAS) pooled data, we selected 1400 metabolites and 731 immunocyte phenotypes with eight lymphoma subtypes for two-sample bi-directional MR analysis. In addition, we used two-step MR to quantify the proportion of metabolite effects on lymphomas mediated by immunocyte phenotype. This study yielded a bidirectional causal relationship between 17 metabolites and lymphoma and a bidirectional causal relationship between 12 immunocyte phenotypes and lymphoma. In addition, we found causal associations between metabolites and lymphomas, three groups of which were mediated by immunocyte phenotypes. Among them, CD27 on plasmablast/plasma cell (PB/PC) was a mediator of the positive association of arginine to glutamate ratio with chronic lymphocytic leukemia, with a mediator ratio of 14.60% (95% CI=1.29-28.00%, P=3.17 × 10-2). Natural killer (NK) cells as a percentage of all lymphocytes(NK %lymphocyte) was a mediator of the negative association of X-18922(unknown metabolite) levels with diffuse large B-cell lymphoma, with a mediation proportion of -8.940% (95% CI=-0.063-(-17.800) %, P=4.84 × 10-2). CD25 on IgD- CD24- B cell was the mediator of the positive association between X-24531(unknown metabolite) levels and diffuse large B-cell lymphoma, with a mediation proportion of 13.200% (95% CI=-0.156-26.200%, P=4.73 × 10-2). In the present study, we identified a causal relationship between metabolites and lymphoma, in which immunocyte phenotypes as mediators are involved in only a minor part. The mediators by which most metabolites affect the risk of lymphoma development remain unclear and require further exploration in the future.

Effect of the gut microbiome and inflammation-related proteins on oral leukoplakia: a Mendelian randomization study and mediation analysis.

Oral leukoplakia (OL) is the most common potentially malignant disease of the oral cavity. In recent years, studies have identified a correlation between the gut microbiota (GM) and oral cancer, in addition, inflammation-related proteins have been reported to play an important role in the development of OL. However, the causal relationship between gut microbiota and OL, as well as whether cytokines play a mediating role, remain unclear. In this Mendelian randomization (MR) study, the genome-wide association studies (GWAS) (n=18340) of the MiBioGen consortium microbiome was used as exposure data. Genetic variation data related to OL were extracted from the Finngen R9 project (513 cases of OL and 411668 controls). The 91 inflammation-related proteins obtained in the literature serve as potential mediators. Two-sample Mendelian randomization analysis was applied to infer causality using Inverse Variance Weighted (IVW), MR Egger, weighted media, simple mode and weighted mode method. Subsequently, sensitivity analysis was conducted to ensure the robustness of the MR results. In addition, we conducted reverse MR analysis to alleviate reverse causality. Finally, we used mediation analysis to determine the pathway mediated by inflammation-related proteins from the gut microbiota to OL. The five bacterial taxa in the gut microbiota indicate a potential causal relationship with the development of OL. Notably, family Clostridiaceae1 was negatively correlated with the risk of OL development, while genus Dorea, genus Ruminococcus1, genus Senegalimasilia and genus Veillonella were positively associated with the risk of OL development. In addition, this study identified a potential causal relationship between interleukin-10 receptor subunit alpha (IL-10RA), interleukin-18 receptor 1(IL18-R1) and the occurrence of OL. In addition, intermediary analysis indicates that IL18-R1 mediated the pathway between the gut microbiota genus Senegalimasilia and OL. In summary, our research emphasize the complex relationship between gut microbiota, inflammation-related proteins and OL. The identified associations and mediating effects provide new insights into potential therapeutic approaches for targeting the gut microbiota in the management of OL, and contribute to its prevention, diagnosis and treatment.

Causal relationship between Lipdome and Chronic Obstructive Pulmonary Disease and Asthma: Mendelian randomization

Genetic risk significantly influence susceptibility and heterogeneity of chronic obstructive pulmonary disease (COPD) and asthma, and increasing evidence suggests their close association with lipdome. However, their causal relationship remains unclear. In this study, we conducted a two-sample MR (Mendelian randomization) analysis using publicly available large-scale genome-wide association studies (GWAS) data to evaluate the causal impact of lipdome on COPD and asthma. The inverse variance weighted (IVW) method served as the primary analysis method, and multiple sensitivity and heterogeneity tests were performed to assess the reliability of the results. Finally, a Meta-analysis was conducted on lipdome with significant causal relationships to validate the robustness of the results. Our findings suggest that Sterol ester (27:1/18:2), Phosphatidylcholine (15:0_18:2), (16:0_18:2), (16:0_20:2), (17:0_18:2), (18:1_18:1), (18:1_18:2), (18:1_20:2), Triacylglycerol (54:3), and (56:4) levels are protective factors for COPD, while levels of Phosphatidylcholine (16:0_22:5), (18:0_20:4), and (O-16:0_20:4) are risk factors for COPD. Meta-analysis of lipids causally related to COPD also indicates significant results. Phosphatidylcholine (16:0_20:4), (16:0_22:5), and (18:0_20:4) levels are risk factors for asthma, while Phosphatidylcholine (18:1_18:2), (18:1_20:2), and Sphingomyelin (d38:1) levels are protective factors for asthma. However, the lack of statistical significance in the Meta-analysis may be due to heterogeneity in research methods and data statistics. This study indicates that 4 lipdome species have significant correlations with COPD and asthma. Phosphatidylcholine (18:1_18:2) and (18:1_20:2) are protective factors, while Phosphatidylcholine (16:0_22:5) and (18:0_20:4) are risk factors. Additionally, due to differences in molecular subtypes, phosphatidylcholine, sterol ester, and triacylglycerol exhibit differential effects on the diseases.

Causal effects of lipid-lowering drugs on skin diseases: a two-sample Mendelian randomization study.

Although previous studies have indicated an association between low-density lipoprotein (LDL) and skin diseases, their causal effects remain inconclusive. This study aimed to assess the causal relationship between genetically proxied lipid-lowering drugs and skin cancers and psoriasis. Two-sample Mendelian randomization (MR) analysis was performed using single-nucleotide polymorphisms (SNPs) from genome-wide association studies (GWAS). The inverse-variance weighted (IVW) method was used to determine causal relationships. The "leave-one-out" sensitivity test, Cochran's Q-statistic and MR-Egger intercept were used to assess heterogeneity and horizontal pleiotropy. We identified 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGCR) and proprotein convertase subtilisin-kexin type 9 (PCSK9) as genetically proxied lipid-lowering drugs. Genetically proxied inhibition of HMGCR (stains) was causally associated with reduced risk of nonmelanoma skin cancer (OR 0.982, 95% CI 0.967-0.997, p = 0.016 by weighted median; OR 0.977, 95% CI 0.966-0.989, p < 0.001 by IVW) and psoriasis (OR 0.585, 95% CI 0.378-0.905, p = 0.016 by IVW), while PCSK9 inhibition (alirocumab) was causally associated with reduced risk of psoriasis (OR 0.560, 95% CI 0.413-0.761 by weighted median; OR 0.564, 95% CI 0.447-0.712 by IVW; p < 0.001) in the ieu-b-5089 dataset. Similar results were observed in the ieu-b-110 dataset for HMGCR and PCSK9. Sensitivity analysis revealed no evidence of heterogeneity or horizontal pleiotropy. This study revealed the existing HMGCR inhibitors (stains) might be protective for reducing nonmelanoma skin cancer risk, and HMGCR inhibitors (stains) and PCSK9 inhibitor (alirocumab) might be promising for reducing psoriasis risk in the European population.

Causal links between blood inflammation markers and postherpetic neuralgia risk: insights from a two-sample Mendelian randomization study.

Previous studies have suggested an association between blood inflammation-related factors and postherpetic neuralgia. However, the causal relationship between blood inflammation-related factors and postherpetic neuralgia remains unclear. We employed a bidirectional Two-sample Mendelian randomization (MR) analysis to explore the causal relationship between blood inflammation-related factors and postherpetic neuralgia. The instrumental variables were obtained from a large Genome-wide association study (GWAS) meta-analysis dataset of European descent. The instrumental variables of the blood inflammation-related factors come from the database numbers GCST004420 to GCST004460 and GCST90029070. Postherpetic neuralgia has 195,191 samples with a total of 16,380,406 single nucleotide polymorphisms (SNPs). MR analyses were performed using inverse-variance weighted, MR-Egger, and weighted median methods. The MR results revealed a significant causal effect of Macrophage Inflammatory Protein 1 Beta (MIP1β) on reducing the risk of postherpetic neuralgia (95%CI = 0.492-0.991, p = 0.044). Additionally, higher levels of interleukin (IL)-10 (95%CI = 0.973-0.998, p = 0.019) and IL-12p70 (95%CI = 0.973-0.997, p = 0.013) were associated with a lower risk of postherpetic neuralgia. Other inflammatory markers showed no significant causal relationship with this condition. This study identifies MIP1β, IL-10, and IL-12p70 as potential therapeutic targets for preventing or treating postherpetic neuralgia, underscoring the need for further research in this area.

Causal relationship between 150 skin microbiomes and prostate cancer: insights from bidirectional mendelian randomization and meta-analysis.

Despite relevant research, the relationship between skin microbiomes and prostate cancer remains controversial. This study utilizes bidirectional Mendelian randomization (MR) analysis combined with meta-analysis to explore the potential link between the two. This study aims to identify the causal relationship between 150 skin microbiomes and prostate cancer (PCa) using bidirectional Mendelian randomization (MR) and meta-analysis. This study employed a comprehensive Bidirectional Two-sample MR analysis using publicly available genetic data to ascertain the relationship between 150 skin microbiomes and PCa. We conducted extensive sensitivity analyses, tests for heterogeneity, and assessments of horizontal pleiotropy to ensure the accuracy of our results. Subsequently, we conducted a meta-analysis to strengthen our conclusions' robustness further. Finally, we performed reverse causal verification on the positive skin microbiomes and PCa. After conducting a meta-analysis and multiple corrections of the MR analysis results, our findings reveal a correlation between Neisseria in dry skin and PCa risk, identifying it as a risk factor. The IVW result shows an Odds Ratio (OR) of 1.009 (95% Confidence Interval [CI]: 1.004-1.014, P = 0.027). Furthermore, the reverse MR analysis indicates the absence of an inverse causal relationship between the two. Apart from the identified skin microbiome, no significant associations were found between the other microbiomes and PCa. The study identified a correlation between Neisseria in dry skin, one of the 150 skin microbiomes, and the risk of developing PCa, establishing it as a risk factor for increased susceptibility to PCa.

Diet-derived circulating antioxidants and functional outcome after ischemic stroke: Evidence from genetic studies

ObjectiveDiet-derived circulating antioxidants have been associated with functional outcome after ischemic stroke (IS), but the causality remains unclear. The aim of our study is to explore the potential causal effect of diet-derived circulating antioxidants on long-term functional outcome (at 3 months) following IS through the utilization of the Mendelian randomization (MR) approach. Materials and MethodsFor this two-sample MR analysis, genetic variants associated with the diet-derived circulating antioxidants, including selenium, zinc, vitamin A (retinol), vitamin C, and vitamin E (α-tocopherol and γ-tocopherol), were identified in a large-scale Genome-Wide Association Studies (GWAS) database and utilized as instrumental variables (IVs). Summary data for long-term functional outcome after IS were obtained from the Genetics of Ischemic Stroke Functional Outcome (GISCOME) network of 6021 patients. Our study used the Inverse-variance weighting method as our primary MR method and also performed a series of sensitivity analyses for pleiotropy and heterogeneity. ResultsWe observed that selenium (odds ratio (OR)=0.81; 95% confidence interval (CI): 0.68-0.97; p=0.02) was significantly associated with poor functional outcome (modified Rankin Scale score≥3) after IS. Genetic liabilities to other diet-derived circulating antioxidants were not strongly associated with functional outcome after IS (all p>0.05). Sensitivity analyses confirmed the reliability of these results. ConclusionThis MR study suggested the positive effect of selenium on the long-term functional outcome after IS. Giving a longer period of selenium exposure can be used as a potential treatment to improve recovery after IS.

Exploring the Causal Association between Morning Diurnal Preference and Psychiatric Disorders: A Bidirectional Two-Sample Mendelian Randomization Analysis.

The causal connection between morning diurnal preference and psychiatric disorders remains enigmatic. Using bidirectional two-sample Mendelian randomization (MR), we aim to explore the potential causal associations between morning diurnal preference and seven prominent psychiatric disorders. MR is a genetic epidemiological method that leverages genetic variants as instrumental variables to infer causal associations between exposures and outcomes. We obtained morning diurnal preference data from genome-wide association study (GWAS) datasets and identified 252,287 individuals as morning people. Psychiatric disorder data were sourced from the FinnGen consortium R9 dataset. Our primary analysis used the inverse-variance weighted (IVW) approach to evaluate the overall causal effect by combining the estimates from each genetic variant. Addition analyses, including weighted median, MR-Egger regression, weighted mode, and simple mode techniques were conducted to ensure robustness. Being a morning person is related to reduced odds of multiple psychiatric disorders, including depression or dysthymia (OR: 0.93, 95% CI: 0.88, 0.999), anxiety disorders (OR: 0.90, 95% CI: 0.84, 0.96), self-harming behaviors (OR: 0.87, 95% CI: 0.76, 0.99), substance-use disorders (OR: 0.81, 95% CI: 0.71, 0.93), alcohol dependence (OR: 0.82, 95% CI: 0.73, 0.92), alcohol use disorders (OR: 0.85, 95% CI: 0.76, 0.94), acute alcohol intoxication (OR: 0.86, 95% CI: 0.76, 0.96), schizophrenia (OR: 0.77, 95% CI: 0.65, 0.92), and schizophrenia or delusion (OR: 0.80, 95% CI: 0.70, 0.92). Alcohol dependence (OR: 0.97, 95% CI: 0.94, 0.999) and alcohol use disorders (OR: 0.96, 95% CI: 0.94, 0.99) were also related to a lower morning diurnal preference. Our study provides evidence that being a morning person is a protective factor for various psychiatric disorders from a genetic perspective. The results provide insights for potential targeted interventions to improve mental wellbeing.

Study of the causal relationship between gastroesophageal reflux disease and hypertension through two-sample Mendelian randomization analysis.

The purpose of this study was to investigate the causal relationship between gastroesophageal reflux disease (GERD) and hypertension using a two-sample Mendelian randomization analysis. The associated data of GERD with hypertension were derived from the genome-wide association study (GWAS) database, and two-sample Mendelian randomization (MR) analysis was performed using methods including inverse variance weighting (IVW), MR-Egger, and weighted median (WM) to investigate the causal association between GERD and hypertension. A total of 16 single nucleotide polymorphisms (SNPs) strongly associated with GERD were screened out, and the IVW suggested a causal relationship between GERD and hypertension (OR: 1.057; 95% CI: 1.044-1.071; P < 0.05). The weighted median also showed a similar relationship (OR: 1.051, 95% CI: 1.032-1.07; P < 0.05). In addition, no heterogeneity or horizontal pleiotropy was observed, suggesting a robustness of the outcome. There is a positive causal relationship between GERD and hypertension.

Microbiome-metabolome analysis insight into the effects of high-salt diet on hemorheological functions in SD rats.

The present study examined the effect of two dietary regimens with elevated salt concentrations (4% and 8% salt) on hemorheological functions of SD rats, and explored the underlying mechanisms mainly through microbiome-metabolome analysis. An 8% HSD substantially altered the hemorheological parameters, and compromised intestinal barrier integrity and reduced the short-chain fatty acid levels. The microbiome-metabolome analysis revealed that 49 genus-specific microorganisms and 156 metabolites showed a consistent trend after exposure to both 4% and 8% HSDs. Pathway analysis identified significant alterations in key metabolites within bile acid and arachidonic acid metabolism pathways. A two-sample Mendelian randomization (MR) analysis verified the link between high dietary salt intake and hemorheology. It also suggested that some key microbes and metabolites (such as Ruminococcaceae_UCG-005, Lachnospiraceae_NK4A136, Ruminiclostridium_6, and Ruminococcaceae_UCG-010, TXB-2, 11,12-diHETrE, glycochenodeoxycholate) may involve in abnormalities in blood rheology caused by high salt intake. Collectively, our findings underscored the adverse effects of high dietary salt on hemorheological functions and provide new insight into the underlying mechanism based on microbiome-metabolome analysis.

Relationships between screen time and childhood attention deficit hyperactivity disorder: a Mendelian randomization study.

In previous observational studies and meta-analyses, childhood attention deficit hyperactivity disorder (ADHD) is found to have a significant association with screen time. However, the causal associations between them remain unclear. This study performed a bidirectional two-sample Mendelian randomization (MR) analysis to confirm the causality between screen time and childhood ADHD. Large-scale genome-wide association studies (GWAS) datasets derived from the Psychiatric Genomics Consortium (PGC) and the UK Biobank were used to identify single nucleotide polymorphisms (SNPs) associated with exposure and outcome. Four categories of datasets were selected to represent screen time. The SNPs that are significantly associated with exposure data (P < 5e-08) and have a strong correlation with the exposure in the F-statistic (F > 10) were selected as instrumental variables. This study also used the PhenoScanner V2 database and the LDlink webtool to exclude confounding factors, and the MR-PRESSO method (p < 0.05) was employed to eliminate outliers with bias. Five commonly used methods were employed to assess the interaction and the Inverse Variance Weighted (IVW) method was utilized as the primary basis for determining the MR estimates in this study. The MR analysis revealed that the length of mobile phone use (OR, 1.848; 95% CI, 1.3360-2.5558; p=2.07e-4) and the time spent watching television (OR, 2.104; 95% CI, 1.3958-3.1703; p=3.8e-4) increased the risk of childhood ADHD. Although the causal relationships were exclusively identified through the IVW and weighted median methods, the results retained their statistical significance following correction. In the reverse analysis, no evidence was found to support an effect of childhood ADHD on screen time. The sensitivity analysis conducted on the significant findings revealed no evidence of horizontal pleiotropy or heterogeneity. This study provides some evidence for the causality of screen time and childhood ADHD. Given the limitations of our study, further research is required to comprehensively investigate this relationship.

Phosphatidylcholine's influence on Dysmenorrhea: conclusive insights from Mendelian randomization analysis.

This study aimed to investigate the causal relationship between phosphatidylcholine (PC) levels and dysmenorrhea using Mendelian randomization (MR) analysis. We conducted a two-sample MR analysis using GWAS data on PC levels and dysmenorrhea. Single nucleotide polymorphisms (SNPs) associated with PC levels were used as instrumental variables. MR-Egger regression and inverse variance weighting (IVW) were used to estimate the causal effect of PC levels on dysmenorrhea. Sensitivity analyses were performed to assess the robustness of the results. The IVW analysis revealed a significant positive association between higher PC levels and dysmenorrhea (OR: 1.533, 95% CI: 1.039-2.262, P = 0.031). The MR-Egger regression did not detect pleiotropy. Sensitivity analyses confirmed the robustness of the results. This study provides evidence suggesting a causal link between increased PC levels and dysmenorrhea. Further research is needed to understand the biological mechanisms underlying this relationship and to explore potential therapeutic implications.

The potential protective effect of 3-Hydroxybutyrate against aortic dissection: a mendelian randomization analysis

Background3-Hydroxybutyrate, also called β-hydroxybutyrate, is a significant constituent of ketone bodies. Previous observational and experimental studies have suggested that ketogenic diet, especially 3-hydroxybutyrate, may have a protective effect against cardiovascular disease. However, the relationship between ketone bodies, especially 3-hydroxybutyrate, and aortic dissection remains uncertain.Materials and methodsPublicly accessible data from genome-wide association study (GWAS) was utilized to obtain information on ketone bodies, including 3-hydroxybutyrate, acetoacetate and acetone as exposure respectively, while GWAS data on aortic dissection was used as outcome. Subsequently, two-sample Mendelian randomization (MR) analysis was conducted to examine the potential relationship between ketone bodies and aortic dissection. Then, reverse and multivariate Mendelian randomization analyses were performed. Additionally, sensitivity tests were conducted to assess the robustness of MR study.ResultsThe inverse-variance weighted (IVW) method of Mendelian randomization analysis of gene prediction observed a negative correlation between 3-hydroxybutyrate and risk of aortic dissection (OR 0.147, 95% CI 0.053–0.410). Furthermore, consistent findings were obtained through the implementation of the weighted median, simple mode, Mendelian randomization-Egger (MR-Egger), and weighted mode methods. After adjusting acetoacetate (OR 0.143, 95% CI 0.023-0.900) or acetone (OR 0.100, 95% CI 0.025–0.398), MR analysis of gene prediction still observed a negative correlation between 3-hydroxybutyrate and risk of aortic dissection. No indications of heterogeneity or pleiotropy among the SNPs were detected.ConclusionThe findings from the MR analysis demonstrated that genetically predicted 3-hydroxybutyrate exhibits a protective effect against aortic dissection.