The causality between C-reactive protein and asthma: a two-sample Mendelian randomization analysis.

BackgroundHepatocellular carcinoma (HCC) is the most common primary liver cancer worldwide. Multiple observational studies demonstrated a negative association between the use of antithrombotic agents and the risk of HCC. However, the precise causal relationship between these factors remains uncertain. Therefore, our study used a two-sample Mendelian randomization (MR) analysis to assess the causal link between these two factors.MethodThe summary statistics of single nucleotide polymorphisms (SNPs) associated with the use of antithrombotic agents were acquired from a genome-wide association study (GWAS) performed on individuals of European descent. A two-sample MR analysis was performed using the inverse variance weighting (IVW), the weighted median estimate, the MR-Egger regression, and the weighted-mode estimate. Sensitivity analysis of the primary findings was performed using MR-PRESSO, MR-Egger regression, Cochran’s Q test, and Leave-one-out analysis.ResultsTen SNPs associated with the use of antithrombotic agents were selected as instrumental variables. The MR analysis performed using the four methods mentioned above revealed a negative causal association between the use of antithrombotic agents and HCC. Univariate MR estimates based on the inverse variance weighting (IVW) method suggested a negative causal association between the use of antithrombotic agents and HCC [odds ratio (OR) 0.444, 95% confidence interval (CI) 0.279 to 0.707, P = 0.001]. The other methods also produced similar results. No heterogeneity and horizontal pleiotropy were found.ConclusionOur findings suggested an inverse causal association of antithrombotic agents with the risk of HCC.

BackgroundRecent observational research has documented that dermatomyositis (DM) has lower gut microbial diversity and a distinct taxonomic composition[1]. However, the underlying causality remains unclear.ObjectivesTo explore the potential causal associations between...

The causal association between vitamin E status and osteoarthritis (OA) remains controversial in previous epidemiological studies. We employed a Mendelian randomization (MR) analysis to explore the causal relationship between circulating alpha-tocopherol levels (main forms of vitamin E in our body) and OA. The instrumental variables (IVs) of circulating alpha-tocopherol levels were obtained from a Genome-wide association study (GWAS) dataset of 7781 individuals of European descent. The outcome of OA was derived from the UK biobank. Two-sample MR analysis was used to estimate the causal relationship between circulating alpha-tocopherol levels and OA. The inverse-variance weighted (IVW) method was the primary analysis in this analysis. We used the MR-Egger method to determine horizontal pleiotropic in this work. The heterogeneity effect of instrumental IVs was detected by MR-Egger and IVW analyses. Sensitivity analysis was performed by removing single nucleotide polymorphism (SNP) one by one. Three SNPs (rs964184, rs2108622, and rs11057830) (P < 5E−8) strongly associated with circulating alpha-tocopherol levels were used in this analysis. The IVW-random effect indicated no causal relationship between circulating alpha-tocopherol levels and clinically diagnosed OA (OR = 0.880, 95% CI 0.626, 1.236, P = 0.461). Similarly, IVW analysis showed no causal association between circulating alpha-tocopherol levels and self-reported OA (OR = 0.980, 95% CI 0.954, 1.006, P = 0.139). Other methods of MR analyses and sensitivity analyses revealed consistent findings. MR-Egger and IVW methods indicated no significant heterogeneity between IVs. The MR–Egger intercept showed no horizontal pleiotropic. The results of this linear Mendelian randomization study indicate no causal association between genetically predicted alpha-tocopherol levels and the progression of OA. Alpha-tocopherol may not provide beneficial and more favorable outcomes for the progression of OA. Further MR analysis based on updated GWASs with more IVs is required to verify the results of our study.

Although prior observational studies have suggested that patients with non-alcohol fatty liver disease (NAFLD) may have a higher risk of coronary artery calcification (CAC), these findings remain controversial. This study aimed to explore the causal association between NAFLD and CAC at genetic level by two-sample Mendelian randomization (MR) analysis. Utilizing summary-level data from multiple large-scale genome-wide association studies (GWAS) in European populations, a two-sample MR analysis was initially conducted to explore the potential causal association between NAFLD and CAC. The results of the MR analysis were pooled through random-effect meta-analysis. The inverse variance weighting (IVW) method served as the primary approach for MR analysis. Additionally, the weighted median, MR-Egger and MR-pleiotropy residual sum and outlier (MR-PRESSO) methods was applied for sensitivity analysis. Summary-level data on liver fatty content was utilized for validation analysis, while summary-level data on cirrhosis served as positive control, further ensuring the validity and robustness of our findings. Reverse MR analysis was performed to assess the association between CAC and NAFLD, employing instrument variables derived from CAC. The MR analysis indicated that genetically predicted NAFLD had no effects on the risk of CAC (Beta: 0.01, 95% CI: -0.02 to 0.03, P = 0.74). Likewise, the reverse MR analysis found no significant genetic association between CAC and NAFLD (OR: 1.00, 95% CI: 0.96 to 1.06, P = 0.88). Validation analysis yielded consistent results, showing no significant association between fatty liver content and CAC. Our two-sample MR analysis did not support that there is a causal association between NAFLD and CAC at genetic level. The association between NAFLD and CAC reported in some previous observational studies may rely on NAFLD complicated with metabolic disorders, rather than being directly linked to the hepatic steatosis.

Numerous observational studies have found a relationship between systemic lupus erythematosus (SLE) and epilepsy; however, their causal relationship remains unclear. This study aimed to investigate the causal role of SLE in epilepsy or any of its subtypes using a two-sample Mendelian randomization (MR) analysis. Single nucleotide polymorphisms (SNPs) linked to SLE were utilized as instrumental variables in MR analysis to assess their causal impact on epilepsy. The primary MR findings were derived using the inverse variance weighted (IVW) method, which was further supported by the weighted median and MR-Egger regression techniques. Additionally, sensitivity analyses, including Cochran's Q test and pleiotropy tests, were conducted to evaluate the influence of these SNPs on epilepsy, particularly looking for signs of horizontal pleiotropy and heterogeneity. We selected 43 SNPs that reached genome-wide significance from genome-wide association studies (GWASs) on SLE to serve as instrumental variables in this study. The IVW method showed no evidence to support a causal association between SLE and epilepsy (all epilepsy: odds ratio (OR) = 1.006, 95% confidence interval (CI) = 0.994-1.018; focal epilepsy: OR = 1.006, 95% CI = 0.994-1.019; generalized epilepsy: OR = 1.015, 95% CI = 0.996-1.035). Other MR complementary methods revealed consistent results. Furthermore, there was no evidence indicating heterogeneity or horizontal pleiotropy. The findings of MR analysis did not support a genetically predicted causal relationship between SLE and epilepsy, but emphasized the need for further research on shared pathophysiological mechanisms, particularly the role of immune system abnormalities and potential influences such as chronic inflammation and therapeutic interventions. The etiology of epilepsy is complex and diverse, including immune factors. Through a Mendelian randomization analysis, we did not find evidence of a genetic causal relationship between systemic lupus erythematosus and epilepsy. However, this does not invalidate epidemiological evidence, and further exploration is needed to investigate factors influencing the relationship between the two.

Association between age at first birth and postpartum depression: A two-sample mendelian randomization analysis

The correlation between obesity and primary open-angle glaucoma (POAG) has not yet been fully established. The aim of this study was to investigate the causal relationship between obesity and POAG by a two-sample Mendelian randomization (MR) study. In this study, body mass index (BMI), an index to evaluate general obesity, and waist and hip circumference, indices to evaluate abdominal obesity, were selected as exposures in MR analysis. Single-nucleotide polymorphisms (SNPs) were chosen as instrumental variables (IVs). Summary data from genome-wide association studies (GWASs) based on a European ancestry by Locke et al., with regard to BMI, and Shungin et al., with regard to waist and hip circumference, were used. Genetic predictors of POAG were obtained from public GWAS summary data. To assess the causal effect of obesity on POAG, the inverse variance-weighted (IVW) method was used as the primary method, and other methods, such as MR–Egger, weighted median, simple mode, and weighted mode, were also used as complementary analyses. Finally, we performed Cochran’s Q statistic to assess heterogeneity, and sensitivity analysis was performed to evaluate the reliability and stability of the MR results. MR analysis showed that BMI has a positive effect on the risk of POAG, with 1 standard deviation (SD) increase in BMI; the risk of POAG increases by approximately 90.9% [OR = 1.909; 95% CI= (1.225, 2.975); p = 0.0042)] (analyzed by IVW); there were no heterogeneity and pleiotropy in the result; and waist circumference also had a positive effect on the risk of POAG [OR = 2.319; 95% CI= (1.071, 5.018); p = 0.033)] analyzed by weighted median. As hip circumference increases, with 1 SD increase in hip circumference, the risk of POAG increases by approximately 119% [OR = 2.199; 95% CI= (1.306, 3.703); p = 0.00305)] estimated by IVW, there were not heterogeneity and pleiotropy as for the result. Our study for the first time confirms that obesity might increase the risk of POAG using two-sample MR analysis. These results might provide guidance on the prevention and treatment of POAG.

BackgroundVenous thromboembolism (VTE) is still one of the most severe health issues, increasing mortality and lengthening hospital stays. Different abundances of gut microbiota have been clinically linked to VTE and coagulopathy. However, whether gut microbiota affected VTE formation remained uncertain.MethodsThe causative links between VTE and 211 gut microbiota at phylum, class, order, family and genus level were separately investigated using two-sample Mendelian Randomization (MR) analysis. Firstly, single nucleotide polymorphisms (SNPs) locus-wide significantly (P < 1.0 × 10− 5) related with gut microbiome abundance were extracted from large genome-wide analysis (GWAS) meta-analysis summary data. Instrumental variables (IVs) without pleiotropy were selected using the PhenoScanner and MR PRESSO test. Then, the MR analysis was implemented using the inverse variance weighted (IVW) method. Moreover, weighted median method, MR Egger method, simple median method and MR PRESSO were conducted to validate the causal associations. The reliability of the results was also assessed utilizing various sensitivity analyses, reverse MR analysis and multivariate Mendelian Randomization analysis (MVMR).ResultsWe found the phylum Firmicutes was robustly protective against VTE with MR analysis. Moreover, five taxa of Actinobacteria phylum (Bifidobacteriales order, Actinomycetales order, Bifidobacteriaceae family, Actinomycetaceae family, Slackia genus) and two taxa of Firmicutes phylum (Bacillales order, Lachnospiraceae UCG-010 genus) were suggestively protective for VTE. While three taxa of Firmicutes phylum (Bacilli class, Lactobacillales order and Lactococcus genus) might suggestively increase the risk of VTE. Sensitivity analyses indicated no significant horizontal pleiotropy, heterogeneity, or reverse causal associations. Furthermore, MVMR analysis unveiled independently positive causal association of Firmicutes phylum and Lachnospiraceae UCG-010 genus with risk of VTE.ConclusionTwo taxa of gut microbes (Firmicutes phylum and Lachnospiraceae UCG-010 genus) were independently protective against VTE, which suggests a potential avenue for developing new cost-effective strategies with minor side effects for VTE prevention and treatment.

Primary biliary cholangitis (PBC) is a complex, chronic, cholestatic liver disease with an autoimmune etiology. While plasma metabolites are crucial indicators of physiological and pathological states, their involvement in PBC pathogenesis remains unclear. To address this knowledge gap, we performed a rigorous two-sample Mendelian randomization (MR) analysis to assess the causal associations of 1,400 plasma metabolites with PBC. Genome-wide association data for 1,400 plasma metabolites and PBC were obtained from established public databases. The inverse-variance weighted (IVW) method was the primary method used for MR analysis. Sensitivity analyses and heterogeneity tests were conducted to assess the stability of the MR results. A reverse MR analysis was performed to investigate the possibility of reverse causality. Four plasma metabolites were identified as potential predictors for the occurrence of PBC. Specifically, sphingosine 1-phosphate (OR = 0.65, 95% CI: 0.42-0.98, p = 0.04) and docosadienoate (22:2n6) (OR = 0.57, 95% CI: 0.36-0.90, p = 0.01) were implicated in conferring a protective effect against PBC. Conversely, homoarginine (OR = 1.34, 95% CI: 1.04-1.72, p = 0.02) and campesterol (OR = 1.19, 95% CI: 1.01-1.40, p = 0.03) were associated with an increased risk of PBC. There was no evidence of reverse causality between PBC and the identified plasma metabolites. This study utilized a two-sample Mendelian randomization approach to explore the causal relationship between 1,400 plasma metabolites and PBC. We identified four plasma metabolites that may have a causal relationship with the development of PBC. The metabolites identified hold promise as prognostic indicators and could illuminate novel pathways for therapeutic intervention in PBC.

Prior observational research has indicated a potential link between pediatric asthma and united airways disease (UAD). However, these findings could be subject to confounding factors and reverse causation. Therefore, our study utilizes Mendelian randomization (MR) method to further investigate the causal relationship between pediatric asthma and UAD. We conducted a comprehensive two-sample Mendelian randomization (MR) analysis to investigate the association between pediatric asthma and seven groups of UAD, including chronic sinusitis, chronic rhinitis, nasopharyngitis and pharyngitis, chronic diseases of tonsils and adenoids, chronic laryngitis and laryngotracheitis, chronic bronchitis, bronchiectasis, chronic obstructive pulmonary disease (COPD). The present study employed a range of methods for two-sample MR analysis, including inverse variance weighted (IVW), MR-Egger regression, Simple mode, weighted median, and weighted models. The conclusion of the MR analysis primarily relies on the IVW results, while other analytical methods are utilized as supplementary evidence to ensure result robustness in this MR analysis. And sensitivity analyses were conducted, including heterogeneity test, horizontal pleiotropy test, MR-PRESSO test, and leave-one-out analysis to validate the results. The results of the MR analysis indicate significant causal effects of pediatric asthma on chronic rhinitis, nasopharyngitis and pharyngitis (IVW: OR = 1.15, 95%CI: 1.05-1.26, p-value = 0.003), chronic diseases of tonsils and adenoids (IVW: OR = 1.07, 95%CI: 1.00-1.15, p-value = 0.038), chronic bronchitis (IVW: OR = 1.51, 95%CI: 1.42-1.62, p-value <0.001), bronchiectasis (IVW: OR = 1.51, 95%CI: (1.30-1.75), p-value <0.001), and COPD (IVW: OR = 1.43, 95%CI: 1.34-1.51, p-value <0.001). However, no significant causal association was observed between pediatric asthma and chronic sinusitis (IVW: OR = 1.00, 95%CI: 1.00-1.00, p-value = 0.085), chronic laryngitis and laryngotracheitis (IVW: OR = 1.05, 95%CI: 0.90-1.21, p-value = 0.558). Our findings support a potential causal relationship between pediatric asthma and UAD, suggesting that pediatric asthma may be a potential risk factor for various UAD.

We evaluated the causal effects of blood lipid levels on systemic lupus erythematosus with a two-sample Mendelian randomization analysis. Independent single-nucleotide polymorphisms related to blood lipids levels (p < 5 × 10−8) were selected as instrumental variables (IVs) from a published genome-wide association study (GWAS). SLE GWAS analysis that included 4036 cases and 6959 controls of European ancestry provided the related roles between instrumental variables and result (SLE). The causal effects were evaluated with two-sample Mendelian randomization (MR) analyses. According to the inverse-variance weighted approaches, genes predictive of increased LDL cholesterol (OR: 1.131; 95% CI: 0.838, 1.528; p = 0.420), HDL cholesterol (OR: 1.093; 95% CI: 0.884, 1.352; p = 0.412), triglycerides (OR: 0.903; 95% CI: 0.716, 1.137; p = 0.384), Apolipoprotein A-I (OR: 0.854; 95% CI: 0.680, 1.074; p = 0.177), and Apolipoprotein B (OR: 0.933; 95% CI: 0.719, 1.211; p = 0.605) were not causally related to the risk of SLE, consistent with multivariate Mendelian randomization analysis. The reverse-MR analyses showed no massive causal roles between SLE and LDL cholesterol (OR: 0.998; 95% CI: 0.994, 1.001; p = 0.166) as well as Apolipoprotein B (OR: 0.998; 95% CI: 0.994, 1.001; p = 0.229). Nevertheless, a causal role of SLE in decreasing HDL cholesterol (OR: 0.993; 95% CI: 0.988, 0.997; p = 0.002), triglycerides (OR: 0.996; 95% CI: 0.993, 0.999; p = 0.010), and Apolipoprotein A-I (OR: 0.995; 95% CI: 0.990, 0.999; p = 0.026) was validated to some extent. Our study found no causal association between abnormal blood lipids and SLE nor a causal effect between SLE and LDL cholesterol as well as Apolipoprotein B. Nevertheless, some evidence showed that SLE exerted a causal effect on lowering HDL cholesterol, Apolipoprotein A-I, and triglyceride levels.

The cerebrospinal fluid (CSF) metabolites could potentially direct reflecting the biochemical processes involved in central nervous system metabolism. This study aims to delineate the potential causal relationships between CSF metabolites and Glioblastoma (GBM) using Mendelian Randomization (MR) analysis. This research employs a two-sample MR framework, utilizing genetic instrumental variables derived from GWAS datasets corresponding to CSF and plasma metabolites, and GBM. Data from separate samples for the exposure and outcome were analyzed using specialized R packages designed for two-sample MR and Bayesian weighted MR analyses. Significant causal relationships were identified between GBM and several CSF metabolites through two-sample MR analysis mainly using the IVW method. Notably, associations were observed with 3-methoxytyramine sulfate (OR 1.039, 95% CI 1.010 to 1.070, p-value 0.009), caffeine (OR 1.132, 95% CI 1.021 to 1.255, p-value 0.018), dimethyl sulfone (OR 1.087, 95% CI 1.002 to 1.178, p-value 0.043), fructose (OR 0.985, 95% CI 0.969 to 0.998, p-value 0.049), and phenol sulfate (OR 1.074, 95% CI 1.020 to 1.131, p-value 0.007). An inverse causal relationship was also observed between CSF fructose levels (as exposure) and GBM (OR 0.255, 95% CI 0.089 to 0.725, p-value = 0.010), suggesting protective effects. These findings were substantiated through Bayesian MR analysis. The study highlights significant links between specific CSF metabolites and GBM, suggesting that these metabolites may influence tumor biology and could serve as potential biomarkers for GBM diagnosis and progression.

Prior studies have reported connections between cathepsins (CTS) and gynecological cancers; however, the exact causal links are yet to be fully understood. Leveraging publicly accessible genome-wide association study summary datasets, we performed a two-sample bidirectional Mendelian randomization (MR) and multivariate MR (MVMR) analysis, with the inverse variance weighted (IVW) method as the primary approach. MR analysis demonstrated inverse associations between CTSB and cervical cancer (IVW: odds ratio [OR] = 0.9995, 95% confidence interval [CI] = 0.9991–0.9999, P = .0418), CTSE and ovarian cancer (IVW: OR = 0.9197, 95% CI = 0.8505–0.9944, P = .0358), CTSZ and ovarian cancer (IVW: OR = 0.9449, 95% CI = 0.8938–0.9990, P = .0459), CTSE and high grade serous ovarian cancer (IVW: OR = 0.8939, 95% CI = 0.8248–0.9689, P = .0063), and CTSZ and high grade serous ovarian cancer (IVW: OR = 0.9269, 95% CI = 0.8667–0.9913, P = .0268). A positive correlation was identified between CTSH and clear cell ovarian cancer (IVW: OR = 1.1496, 95% CI = 1.0368–1.2745, P = .0081). Nevertheless, subsequent adjustment for the false discovery rate revealed that none of the P-values retained statistical significance (PFDR > 0.05). MVMR analysis results elucidated that CTSZ was inversely associated with cervical cancer (IVW: OR = 0.9988, 95% CI = 0.9981–0.9996, P = .0022). Moreover, a positive association was noted between CTSF and cervical cancer (IVW: OR = 1.0007, 95% CI = 1.0000–1.0014, P = .0364), and similarly, between CTSS and cervical cancer (IVW: OR = 1.0005, 95% CI = 1.0000–1.0011, P = .0490). CTSO exhibited a positive association with non-endometrioid endometrial cancer (IVW: OR = 1.4405, 95% CI = 1.1864–1.7490, P < .001), and CTSH was positively associated with clear cell ovarian cancer (IVW: OR = 1.1167, 95% CI = 1.0131–1.2310, P = .0263). The MVMR analysis findings reveal that CTSZ emerges as a protective element against cervical cancer, whereas CTSF and CTSS represent risk factors for this disease. CTSO stands out as a risk factor for non-endometrioid endometrial cancer, and CTSH acts as a risk factor for clear cell ovarian cancer. This study elucidates causative connections between CTS and gynecological cancers, providing innovative insights for diagnostic and therapeutic optimization.

This study uses bidirectional, two-sample Mendelian randomization (MR) analysis through genome-wide association studies (GWAS) statistics to assess the causal association between periodontitis and breast cancer. Periodontitis data from the FinnGen project and breast cancer data from OpenGWAS was used, with all data subjects being of European ancestry. Periodontitis cases were categorized by probing depths or self-reporting according to the Centers for Disease Control and Prevention (CDC)/American Academy of Periodontology definition. 3046 periodontitis cases and 195,395 control cases along with 76,192 cases of breast cancer and 63,082 control cases were obtained from GWAS data. R (version4.2.1) through TwoSampleMR and MRPRESSO were used for data analysis. Primary analysis was conducted using the inverse-variance weighted method. Horizontal pleiotrophy was corrected and causal effects were examined through detection methods of the weighted median method, weighted mode method, simple mode, MR-Egger regression method, and MR-pleiosis residual and outlier method (MR-PRESSO). A heterogeneity test was adopted for the inverse-variance weighted (IVW) analysis method and MR-Egger regression (P > 0.05). Pleiotropy was evaluated using the MR-Egger intercept value. The P-value of the pleiotropy test was then used to analyze the existence of pleiotropy. Where P > 0.05, the possibility of pleiotropy in the causal analysis was considered to be less or non-existent. Leave-one-out analysis was used to tested the consistency of results. 171 single nucleotide polymorphisms were extracted for MR analysis where breast cancer was the exposure and periodontitis the outcome. The total sample size of periodontitis was 198,441, and 139,274 for breast cancer. Overall results showed breast cancer had no effect on periodontitis (IVW P = 0.1408, MR-egger P = 0.1785, weighted median P = 0.1885), with Cochran's Q analysis showing no heterogenicity amongst these instrumental variables (P > 0.05). 7 single nucleotide polymorphisms were extracted for MR analysis where periodontitis was the exposure and breast cancer the outcome. No significant correlation was found between periodontitis and breast cancer (IVW P = 0.8251, MR-egger P = 0.6072, weighted median P = 0.6848). Based on the use of different MR analysis methods, there is no evidence to support a causal relationship between periodontitis and breast cancer.

Numerous investigations have indicated a correlation between air pollution (AP) and an elevated ischemic stroke (IS) likelihood. The existing literature does not provide a consensus about the possible link between AP and IS. A two-sample Mendelian randomization (MR) analysis was utilized to systematically measure the causal link between AP and ischemic stroke. Furthermore, the mediating impact of inflammatory factors was also performed by a two-step MR. A two-sample MR analysis was utilized to examine the AP impact on the incidence of IS. Additionally, a two-step MR approach was carried out to account for possible mediating variables. The indirect impact was determined by employing the product approach, which included multiplying the AP impact on inflammatory factors by the inflammatory factors' impacts on IS. The MR effect was identified through inverse variance-weighted (IVW) meta-analysis of each Wald Ratio. Additionally, complementary studies were conducted using the weighted median and MR-egger approaches. The IVW method with random effects showed that the per unit increase in genetically predicted PM2.5 was linked to the 0.362-fold elevated ischemic stroke risk (OR: 1.362, 95% CI: 1.032-1.796, p=0.029). Furthermore, the IVM technique, incorporating random effects, demonstrated that the per unit increase in genetically predicted PM2.5 was related to an elevated Interleukin (IL)-1β risk (OR: 1.529, 95% CI: 1.191-1.963, p=0.001), IL-6 (OR: 1.498, 95% CI: 1.094-2.052, p=0.012) and IL-17 (OR: 1.478, 95% CI: 1.021-2.139, p=0.038). IL-1β, IL-6, and IL-17 modulated the PM2.5 impact on ischemic stroke, while the proportion mediated by them was 59.5%. A positive correlation between genetically predicted PM2.5 levels and elevated ischemic stroke risk is mediated by IL-1β, IL-6, and IL-17.