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Results for “mendelian randomization study”

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PubMed2024

No causal relationship between glucose and inflammatory bowel disease: a bidirectional two-sample mendelian randomization study.

BACKGROUND: Association between glucose and inflammatory bowel disease (IBD) was found in previous observational studies and in cohort studies. However, it is not clear whether these associations reflect causality. Thus, this study investigated whether there is such a causal relation between elevated glucose and IBD, Crohn's disease (CD) and ulcerative colitis (UC). METHODS: We performed a two-sample Mendelian Randomization (MR) with the independent genetic instruments identified from the largest available genome-wide association study (GWAS) for IBD (5,673 cases; 213,119 controls) and its main subtypes, CD and UC. Summarized data for glucose which included 200,622 cases and glycemic traits including HbA1c and type 2 diabetes(T2DM) were obtained from different GWAS studies. Primary and secondary analyses were conducted by preferentially using the radial inverse-variance weighted (IVW) approach. A number of other meta-analysis approach and sensitivity analyses were carried out to assess the robustness of the results. RESULTS: We did not find a causal effect of genetically predicted glucose on IBD as a whole (OR 0.858; 95% CI 0.649-1.135; P = 0.286). In subtype analyses glucose was also suggestively not associated with Crohn's disease (OR 0.22; 95% CI 0.04-1.00; P = 0.05) and ulcerative colitis (OR 0.940; 95% CI 0.628-1.407; P = 0.762). In the other direction, IBD and its subtypes were not related to glucose and glycemic traits. CONCLUSIONS: This MR study is not providing any evidence for a causal relationship between genetically predicted elevated glucose and IBD as well as it's subtypes UC and CD. Regarding the other direction, no causal associations could be found. Future studies with robust genetic instruments are needed to confirm this conclusion.

Humans↗

PubMed2026

Plasma lipid species, immune cell traits, and gastric cancer risk: A Mendelian randomization study.

Plasma lipid composition has been linked to multiple cancers, yet its causal contribution to gastric cancer and the potential intermediary role of immune cells remain unclear. We aimed to clarify these relationships and identify specific lipid and immune cell traits that either protect against or promote gastric cancer. We performed a 2-sample, 2-step Mendelian randomization analysis using summary statistics from large genome-wide association studies of gastric cancer (1423 cases, 3,14,193 controls), plasma lipidomics (179 molecular species), and 731 immune cell phenotypes. Independent, genome-wide significant single-nucleotide variants served as instrumental variables. First, we estimated the causal effects of each plasma lipid on gastric cancer. Then, we explored the potential intermediary role of lipid-associated immune cell traits using a 2-step Mendelian randomization framework. Two lipids - phosphatidylethanolamine (18:0 0:0) and phosphatidylcholine (O-18:0 16:1) - were causally associated with a lower risk of gastric cancer. Three immune cell traits (CD8br and CD8dim %leukocyte, IgD on IgD+ CD38- and CD3 on CD28- CD8br) similarly showed protective effects. In contrast, phosphatidylcholine (O-16:1 18:2), triacylglycerol (49:1), triacylglycerol (56:3), and triacylglycerol (56:4) increased gastric cancer risk, as did immune traits such as TD DN (CD4-CD8-)AC, CD19 on memory B cell, CD28 on CD39+ activated Treg, CD45 on CD4+, CD127 on CD28+DN(CD4-CD8-) and CCR2 on CD14+CD16+ monocyte. Exploratory mediation analyses found no statistically significant evidence that immune cell traits mediated the effects of plasma lipids on gastric cancer risk. Specific phosphatidylethanolamines and phosphatidylcholines confer protection against gastric cancer, whereas several triacylglycerols increase risk. However, exploratory mediation analyses provided no statistically significant evidence that immune cell traits mediated these associations.

Humans↗

PubMed2025

Causal relationship between albumin, total protein, and colorectal cancer risk: A 2-sample Mendelian randomization study.

Albumin (ALB) and total protein (TP) are vital constituents of the blood, and their levels and roles in the risk of colorectal cancer (CRC) are of significance. Previous observational studies have reported correlations among ALB, TP, and CRC. However, the existence of a causal relationship between ALB and CRC in European populations has not been adequately investigated and the causal link between TP and CRC remains unexplored. To address these gaps, we applied Mendelian randomization (MR) to investigate the potential causal relationship between ALB, TP, and CRC. Two-sample MR analysis was used to investigate whether there was a causal relationship between ALB, TP, and CRC. Our exposure data were extracted from genome-wide association study (GWAS) databases sourced from the UK Biobank, containing 315,268 and 314,921 Europeans participants for ALB and TP analyses, respectively. Single nucleotide polymorphisms that were significantly associated with ALB and TP were assessed using GWAS datasets. Our data were derived from the FinnGen Consortium CRC GWAS, which contained 6509 CRC cases and 28,7137 controls. Causal inference between ALB, TP, and CRC was performed using 3 MR methods: inverse variance weighting (IVW), MR-Egger, and weighted median. The IVW analysis showed no significant causal association between ALB and CRC (OR = 1.04, 95% CI = 0.89-1.21, P = .65). In contrast, the IVW analysis for TP and CRC showed a significant causal association (OR = 0.78, 95% CI = 0.66-0.92, P = .003), suggesting a reduced risk of CRC. Through a 2-sample MR study investigating the causal relationship between ALB, TP, and CRC in a European population, our findings revealed a significant causal relationship between TP and a reduced risk of CRC.

Humans↗

PubMed2025

Severe traumatic brain injury and risk for osteoporosis: a Mendelian randomization study.

BACKGROUND: The influence of nervous system activity on bone remodeling has been widely reported. Patients with traumatic brain injury (TBI) exhibit a high incidence of osteoporosis (OP). Nevertheless, the relationship between severe TBI (sTBI) and OP remains unclear. We performed Mendelian randomization (MR) analysis to assess the potential causal relationship between sTBI and OP. METHODS: Data on exposure and outcomes were acquired from genome-wide association studies (GWAS). Data on OP was obtained from UK Biobank (5,266 cases of OP and 331,893 controls). Data on sTBI was obtained from FinnGen Consortium (6,687 cases and 370,590 controls). Single nucleotide polymorphisms (SNPs) that underwent strict screening were regarded as instrumental variables. We used the inverse variance weighted (IVW), constrained maximum likelihood and model averaging (CML-MA), MR-Egger, and weighted median methods for causal effect estimation. To test the reliability of the results, sensitivity analysis was performed using Cochran's Q, leave-one-out, MR-Egger intercept, and MR Pleiotropy RESidual Sum and Outlier (MR-PRESSO) tests. RESULTS: The IVW analysis indicates that sTBI and OP have a suggestive association (odds ratio [OR] = 1.004, 95% confidence interval [CI] = 1.001,1.007; p = 0.002), and no heterogeneity (Q = 11.536, p = 0.241) or directional pleiotropy was observed (egger_intercept = 7.368 × 10- 5, p = 0.870). The robustness of the results was validated using a leave-one-out sensitivity test. CONCLUSION: According to the MR analysis, sTBI and OP are likely suggestively related. This finding contributes to the prevention of OP in patients with sTBI and provides genetic evidence supporting the theory that the nervous system regulates bone remodeling.

Humans↗

PubMed2026

Causal determinants of gout in 614,000 adults: A two-sample Mendelian randomization study of dietary, lifestyle, and metabolic traits.

Gout affects over 55 million people worldwide, with prevalence projected to rise by 70% by 2050. Although observational studies have implicated several dietary, lifestyle, and metabolic risk factors, causal relationships remain uncertain because of confounding and reverse causation. Univariable and multivariable two-sample Mendelian randomization (MR) analyses were performed using genome-wide association data from 2 European cohorts: UK Biobank (6543 self-reported gout cases and 456,390 controls) and FinnGen (3576 cases and 147,221 controls). Genetic instruments for 12 exposures, including dried fruit, salad, and cheese intake; smoking initiation; physical activity; body mass index (BMI); and lipid traits, were derived from established genome-wide association study datasets. Inverse-variance weighted regression with multiplicative random effects was the primary analysis, complemented by weighted median, weighted mode, MR-Egger, MR-Pleiotropy RESidual Sum and Outlier, and 3 predefined multivariable models. Benjamini-Hochberg correction was applied across all 24 tests. BMI showed the strongest and most consistent causal effect on gout (FinnGen: odds ratio [OR] = 1.97, 95% confidence interval [CI] = 1.51-2.57; UK Biobank: OR = 1.006, 95% CI = 1.003-1.009; both P < .001) and remained significant in 5 of 6 multivariable models. Triglycerides increased risk in both cohorts (FinnGen: OR = 1.34, 95% CI = 1.08-1.66; UK Biobank: OR = 1.008, 95% CI = 1.004-1.012). These associations survived Benjamini-Hochberg correction, as did high-density lipoprotein cholesterol in UK Biobank (OR = 0.997, 95% CI = 0.994-0.999). Dried fruit intake was inversely associated with gout in FinnGen (OR = 0.34, 95% CI = 0.13-0.92, P = .034) but not in UK Biobank, and did not survive correction for multiple testing. No other exposure reached significance in either cohort. This study provides genetic evidence that BMI is the dominant modifiable causal determinant of gout, with triglycerides contributing independently. Dietary associations were weaker and did not withstand correction for multiple testing, and should be regarded as hypothesis-generating. These findings support prioritizing weight management and metabolic health in gout prevention.

Gout↗

PubMed2026

Genetic Evidence That Stroke Causally Increases Circulating PDGFB Levels: a Two-Sample Mendelian Randomization Study.

Platelet-derived growth factor subunit B (PDGFB) is a key regulator of vascular remodeling, angiogenesis, and blood-brain barrier integrity. Although elevated PDGFB levels have been reported after ischemic injury, whether stroke liability itself causally influences circulating PDGFB levels remains unclear. We performed a two-sample Mendelian randomization (MR) analysis to assess the causal effects of genetically predicted all stroke, ischemic stroke, and cardioembolic stroke on plasma PDGFB concentrations. Genetic instruments were obtained from large-scale GIGASTROKE genome-wide association studies, and outcome data were derived from a proteomics GWAS. Instruments were then filtered by removing variants associated with established cardiovascular risk factors in a phenome-wide screen and outliers identified by RadialMR. The inverse variance-weighted (IVW) method was used as the primary analysis, complemented by weighted median, weighted mode, and MR-Egger approaches. Sensitivity analyses included Cochran's Q statistics, MR-Egger intercept tests, single-SNP analyses, leave-one-out analyses, and MR-PRESSO. IVW analysis demonstrated a significant positive causal association between genetic liability to all stroke and plasma PDGFB levels (β = 0.209, SE = 0.062, 95% CI 0.088 to 0.331, p = 7.3 × 10-4). A similar association was observed for ischemic stroke (β = 0.155, SE = 0.059, 95% CI 0.039 to 0.270, p = 0.009), with directionally consistent results across sensitivity analyses. MR-Egger regression for ischemic stroke initially suggested pleiotropy.After removal of a radial-MR outlier (rs2289252), the intercept was attenuated and no longer statistically significant (- 0.0190, p = 0.282). In contrast, no evidence of a causal association was found between cardioembolic stroke liability and plasma PDGFB levels across all MR methods (β = - 0.078, SE = 0.087, 95% CI - 0.248 to 0.092, p = 0.368). These findings provide genetic evidence that liability to stroke, particularly ischemic stroke, is causally associated with increased circulating PDGFB levels, whereas cardioembolic stroke does not show such an effect. This suggests that elevated PDGFB reflects vascular responses specific to ischemic stroke rather than a general consequence of all stroke subtypes.

Humans↗

PubMed2026

Genetically predicted associations between blood cell perturbation responses and bronchiectasis through immune mediation: A Mendelian Randomization study.

BACKGROUND: Bronchiectasis is a chronic airway disease characterized by persistent inflammation and structural damage, with substantial clinical and etiologic heterogeneity. Although previous studies have identified associations between blood cells and bronchiectasis, the causal relationships remain unclear. Moreover, the mechanisms underlying blood cell perturbation responses and their potential mediation by immune cells in disease progression are largely unexplored. METHODS: Two-sample Mendelian randomization (MR) analysis was used to explore genetically predicted associations among immune cell traits, blood cell perturbation response phenotypes, and bronchiectasis, based on genome-wide association study summary data. Mediation MR analysis was further applied to assess whether immune cells mediate these associations. Multiple sensitivity analyses, including tests for heterogeneity and horizontal pleiotropy, were performed to evaluate the validity and robustness. RESULTS: Five blood cell perturbation response phenotypes and twenty-nine immune cell traits showed significant genetically predicted associations with bronchiectasis. Mediation analysis showed that natural killer (NK) cell absolute count partially mediated the causal effect between the eosinophil perturbation response and bronchiectasis, with a mediation proportion of 9.626%. CD38 on transitional B cells mediated the causal effect between the monocyte perturbation response and bronchiectasis, with a mediation proportion of 10.580%. Additionally, CD45 on NK cells played a mediating role in the association between the white blood cell perturbation response and bronchiectasis, with a mediation proportion of 10.651%. CONCLUSION: This study systematically explores genetically predicted associations between blood cell perturbation responses and bronchiectasis and highlights potential immune-mediated pathways. These exploratory findings provide novel genetic insights into the pathogenesis of bronchiectasis and identify potential therapeutic targets for future strategies.

Humans↗

PubMed2025

Causality between telomere length and breast diseases: a two-sample bidirectional Mendelian randomization study.

BACKGROUND: The relationship between telomere length and breast diseases remains unclear, with conflicting evidence for breast cancer. Using an innovative genetic approach, we were the first to comprehensively assess their bidirectional causal relationship. METHODS: Telomere length, breast cancer, benign neoplasm of breast, and breast inflammation were extracted from the genome-wide Association study (GWAS) database as the basis for large-scale population studies. The interaction of telomere length and breast diseases as exposure and outcome factors was analyzed by Mendelian randomization (MR). RESULTS: When telomere length was used as an exposure factor and breast diseases as an outcome, the P value of MR was less than 0.05. Breast cancer (odds ratio (OR) = 1.130, 95% confidence interval (CI) = 1.047-1.219, P = 0.0016), benign neoplasm of breast (OR = 1.002, 95%CI = 1.001-1.004, P = 0.0007) and breast inflammation (OR = 1.487, 95%CI = 1.008-2.191, P = 0.0453). When breast diseases were taken as an exposure factor and telomere length was taken as an outcome, the P value of MR between breast cancer, benign neoplasm of breast, and telomere length was greater than 0.05, and breast inflammation could not be calculated by MR. CONCLUSION: Telomere length is a risk factor for breast diseases, and longer telomeres increase the risk of breast cancer, benign neoplasm of breast, and breast inflammation. However, the reverse study showed no causal association between breast cancer, benign neoplasm of breast and telomere length, and the causal association between breast inflammation and telomere length was not clear. Moreover, further studies are needed to validate our findings in non-European populations.

Mendelian randomization↗

PubMed2026

Assessing the impact of maternal blood pressure during pregnancy on perinatal health: a wide-angled Mendelian randomization study.

BACKGROUND: Observational studies link high blood pressure in pregnancy to numerous adverse pregnancy and perinatal outcomes; however, findings may be affected by residual confounding or reverse causation. This study aimed to assess the causal effect of blood pressure during pregnancy on a range of pregnancy and perinatal outcomes. METHODS: We performed two-sample Mendelian randomization (MR) to assess the effect of systolic and diastolic blood pressure (SBP/DBP) during pregnancy on 16 primary and eight secondary adverse pregnancy and perinatal outcomes. We obtained genetic association data from large-scale meta-analyses of genome-wide association studies involving predominantly European ancestry individuals for SBP/DBP (N = 1,028,980), and pregnancy and perinatal outcomes (N = 74,368-714,899). We used inverse-variance weighted (IVW) MR for main analyses and MR-Egger, weighted median, weighted mode, multivariable MR, and IVW adjusted for fetal genetic effects for sensitivity analyses. RESULTS: A 10 mmHg higher genetically predicted maternal SBP increased the odds of gestational diabetes, induction of labour, low birth weight (LBW), small-for-gestational age (SGA), preterm birth (PTB), and neonatal intensive care unit (NICU) admission (OR ranging from 1.11 [95% CI 1.02 to 1.20] for NICU admission to 1.33 [1.26 to 1.41] for LBW); while decreasing the odds of high birth weight (HBW), large-for-gestational age (LGA), and post-term birth [OR ranging from 0.76 (0.69 to 0.83) for HBW to 0.94 (0.90 to 0.99) for post-term birth]. We did not find evidence that genetically predicted higher maternal SBP was related to miscarriage or stillbirth. The results for maternal DBP were similar to the results for SBP. Overall, the main results were consistent across sensitivity analyses accounting for pleiotropic instruments and fetal genetic effects. CONCLUSIONS: Higher maternal blood pressure reduces gestation duration and fetal growth and increases the risks of induction of labour, gestational diabetes, and neonatal intensive care unit admission. This and other emerging evidence highlight the value of interventions aimed at controlling blood pressure in the population to reduce the burden of adverse pregnancy outcomes.

Humans↗

PubMed2024

Effect of inflammatory cytokines and plasma metabolome on OSA: a bidirectional two- sample Mendelian randomization study and mediation analysis.

BACKGROUND: Obstructive sleep apnea (OSA) is a common sleep disorder. Inflammatory factors and plasma metabolites are important in assessing its progression. However, the causal relationship between them and OSA remains unclear, hampering early clinical diagnosis and treatment decisions. METHODS: We conducted a large-scale study using data from the FinnGen database, with 43,901 cases and 366,484 controls for our discovery MR analysis. We employed 91 plasma proteins from 11 cohorts (totaling 14,824 participants of European descent) as instrumental variables (IVs). Additionally, we conducted a GWAS involving 13,818 cases and 463,035 controls to replicate the MR analysis. We primarily used the IVW method, supplemented by MR Egger, weighted median, simple mode, and weighted mode methods. Meta-analysis was used to synthesize MR findings, followed by tests for heterogeneity, pleiotropy, and sensitivity analysis (LOO). Reverse MR analysis was also performed to explore causal relationships. RESULTS: The meta-analysis showed a correlation between elevated Eotaxin levels and an increased risk of OSA (OR=1.050, 95% CI: 1.008-1.096; p < 0.05). Furthermore, we found that the increased risk of OSA could be attributed to reduced levels of X-11849 and X-24978 (decreases of 7.1% and 8.4%, respectively). Sensitivity analysis results supported the reliability of these findings. CONCLUSIONS: In this study, we uncovered a novel biomarker and identified two previously unknown metabolites strongly linked to OSA. These findings underscore the potential significance of inflammatory factors and metabolites in the genetic underpinnings of OSA development and prognosis.

Female↗

PubMed2024

Relationship between inflammation/immunity and epilepsy: A multi-omics mendelian randomization study integrating GWAS, eQTL, and mQTL data.

OBJECTIVES: Increasing evidence suggests that activated innate/adaptive immunity induces an inflammatory response, thereby participating in epileptogenesis. However, the biological explanation of inflammation/immunity as a potential cause for epilepsy remains largely unknown. This research aimed to determine the causal effects of inflammation/immune-related genes in epilepsy based on multi-omics mendelian randomization (MR). METHODS: We employed summary-data-based MR (SMR) approach to combine GWAS for epilepsy (12,891 cases and 312,803 control) with gene expression quantitative trait loci (cis-eQTL, 31,684 participants) and DNA methylation QTL (cis-mQTL, 1,980 participants) data. Five additional MR methods were then used for sensitivity analyses to confirm the reliability of causal associations. In addition, enrichment analysis of key genes was conducted to provide insight into the biological functions of epilepsy risk variants. RESULTS: A total of 386 inflammation/immune-related genes were selected for further analyses. Primary SMR analysis indicated that 37 DNA methylation sites and six genes regulated by them had potential causal relationship with epilepsy. MR analysis further refined the results, identifying three genes that had a causal effect on epilepsy. Notably, VEGFA (OR: 0.925; 95 % CI: 0.862-0.994) expression was negatively correlated with epilepsy risk, whereas IL16 (OR: 1.076; 95 % CI: 1.028-1.126) and HLA-DPA1 (OR: 1.041; 95 % CI: 1.009-1.074) expressions were positively associated with epilepsy risk. Functional enrichment analysis revealed that the identified genes were involved in GO-BP terms related to VEGF activation signaling and chemotaxis regulation. CONCLUSION: This analysis confirms the causal role of inflammation/immunity in epilepsy, and the identified candidate genes provide clues for drug development in clinical practice.

Humans↗

PubMed2026

Immune Cell-Stratified Regulatory Contexts Associated With BMI-Related Multi-System Disease Risk: A Cell-Stratified Mendelian Randomization Study Using Single-Cell eQTL Data.

AIMS: Body mass index (BMI) is associated with multisystem disease risk, but the immune cell-specific regulatory contexts underlying BMI-related genetic associations with disease outcomes remain unclear. METHODS: We applied a cell-stratified Mendelian randomization framework integrating European-ancestry BMI GWAS data, GWAS datasets for 33 disease outcomes across five disease systems, single-cell cis-eQTL data from 28 peripheral blood immune cell types, and dynamic CD4+ T cell eQTL data. SuSiE-based colocalization was used to identify BMI-associated loci sharing causal variants with immune-cell gene expression. These variants were used as cell-stratified instruments for Mendelian randomization. RESULTS: Across 28 immune cell types, 1326 colocalized variants regulating 1426 genes were identified. In primary MR analyses, genetically predicted BMI showed Bonferroni-significant associations with 26 disease outcomes. Cell-stratified analyses identified 87 Bonferroni-significant associations across 17 disease outcomes. Cardiovascular diseases showed the broadest cell-stratified associations, followed by respiratory and metabolic diseases. CD4+ T cell regulatory contexts contributed one of the largest shares of prioritized associations, and BMI-related effects varied across CD4+ T cell activation states. Cross-disease prioritization highlighted recurrent immune feature genes, including TRAF3 and FGFR1. CONCLUSION: These findings prioritize CD4+ T cell regulatory contexts as potential immunogenetic links between BMI and multi-system disease risk, while requiring further validation in diverse populations and mechanistic models.

Humans↗

PubMed2024

Is there a causal relationship between resistin levels and bone mineral density, fracture occurrence? A mendelian randomization study.

BACKGROUND: In a great many of observational studies, whether there is a relevance of resistin levels on bone mineral density (BMD) and fracture occurrence has been inconsistently reported, and the causality is unclear. METHODS: We aim to assess the resistin levels on BMD and fracture occurrence within a Mendelian randomization (MR) analysis. Exposure and outcome data were derived from the Integrative Epidemiology Unit (IEU) Open genome wide association studies (GWAS) database. Screening of instrumental variables (IVs) was performed subject to conditions of relevance, exclusivity, and independence. Inverse variance weighting (IVW) was our primary method for MR analysis based on harmonized data. Weighted median and MR-Egger were chosen to evaluate the robustness of the results of IVW. Simultaneously, heterogeneity and horizontal pleiotropy were also assessed and the direction of potential causality was detected by MR Steiger. Multivariable MR (MVMR) analysis was used to identify whether confounding factors affected the reliability of the results. RESULTS: After Bonferroni correction, the results showed a suggestively positive causality between resistin levels and total body BMD (TB-BMD) in European populations over the age of 60 [β(95%CI): 0.093(0.021, 0.165), P = 0.011]. The weighted median [β(95%CI): 0.111(0.067, 0.213), P = 0.035] and MR-Egger [β(95%CI): 0.162(0.025, 0.2983), P = 0.040] results demonstrate the robustness of the IVW results. No presence of pleiotropy or heterogeneity was detected between them. MR Steiger supports the causal inference result and MVMR suggests its direct effect. CONCLUSIONS: In European population older than 60 years, genetically predicted higher levels of resistin were associated with higher TB-BMD. A significant causality between resistin levels on BMD at different sites, fracture in certain parts of the body, and BMD in four different age groups between 0-60 years of age was not found in our study.

Bone Density↗

PubMed2025

Causal associations between inflammatory bowel disease and sepsis: a two-sample Mendelian randomization study.

BACKGROUND: Recent observational studies have revealed an inconclusive correlation between inflammatory bowel disease (IBD) and sepsis, accompanied by an uncertain understanding of the causal relationship between the two. To investigate the causality between IBD and sepsis, we employed a two-sample Mendelian randomization (MR) approach. METHODS: A genome-wide significant threshold (P < 5 × 10-8) was achieved in order to identify single nucleotide polymorphisms (SNPs) as instrumental variables (IVs) for two types of IBD, such as Crohn's disease (CD) and ulcerative colitis (UC). Subsequently, the selected SNPs were assessed in relation to three categories of sepsis, namely sepsis, sepsis (critical care), and sepsis (28-day death in critical care). An inverse-variance weighted (IVW) estimation of MR was conducted, followed by sensitivity analysis on multiple dimensions. RESULTS: There was a significant association between genetic liability to CD (IVW: OR, 1.246; 95% CI, 1.090-1.423; P = 0.0012) with sepsis (28-day death in critical care), but not with sepsis (critical care) and sepsis. Whereas UC showed slightly, yet statistically insignificant, higher risk for sepsis (IVW: OR, 1.031; 95% CI, 0.988-1.064; P = 0.064). CONCLUSION: Our study offers genetic evidence that supports a substantial causal relationship between CD and sepsis (28-day death in critical care). To enhance the specificity and objectivity of future research findings, it is recommended to specify the types of IBD and the severity of sepsis. Furthermore, the genetic risk loci related may become potential drug development targets.

Humans↗

PubMed2026

Genetically predicted childhood traits and parental health and risk of pediatric psychiatric disorders: A 2-sample Mendelian randomization study.

The etiology of pediatric psychiatric disorders is complex, involving intergenerational influences and a child's own developmental health. We aimed to investigate the potential effects of genetically predicted childhood traits (childhood obesity, absence epilepsy, intelligence) and parental health traits (longevity, Alzheimer disease, severe depression) on the risk of several childhood and adolescent psychiatric disorders. We employed a 2-sample Mendelian randomization (MR) design using summary statistics from large-scale genome-wide association studies. Data for parental health exposures were primarily from the UK Biobank. Data for childhood trait exposures were from various consortia. Data for outcomes - conduct disorder, mixed conduct and emotional disorders, attention-deficit/hyperactivity disorder (ADHD), autism spectrum disorder (ASD), and broader behavioral/emotional and social disorders - were sourced from FinnGen and the Psychiatric Genomics Consortium, among others. We used the inverse-variance weighted method for the primary analysis, with MR-Egger, weighted median, and weighted mode as additional analyses. To test the robustness of the results, we conducted sensitivity analyses using MR-Egger regression, Cochran Q test for heterogeneity, the MR-pleiotropy residual sum and outlier test, and a leave-one-out analysis. Genetic liability for childhood obesity was associated with an increased risk of ASD (odds ratio = 1.06, P = .016) and ADHD (odds ratio = 1.09, P = .026), even though these associations did not withstand multiple testing correction. No other robust, statistically significant causal associations were identified. Sensitivity analyses showed limited evidence of bias from horizontal pleiotropy for the main findings. Our findings provide MR evidence supporting potential links from genetic liability for childhood obesity to increased risks of ASD and ADHD. These results highlight the importance of considering a child's early-life health trajectory in the etiology of pediatric psychiatric disorders.

Humans↗

PubMed2026

Genetically predicted CXCL16 expression is associated with Parkinson's disease risk and peripheral immune cell dysregulation: a two-sample mendelian randomization study.

BACKGROUND: Parkinson's disease (PD) is a progressive neurodegenerative disorder with limited disease-modifying therapies. PANoptosis, an integrated form of programmed cell death involving apoptosis, pyroptosis, and necroptosis, has been implicated in neuroinflammation-related neurodegeneration. However, the roles of PANoptosis-related genes in PD remain unclear. METHODS: We performed two-sample Mendelian randomization (MR) using cis-eQTL instruments from the eQTLGen Consortium for 30 PANoptosis-related genes, with PD GWAS data from Nalls et al. 2019 as the outcome. Instrumental variables were selected using a hierarchical strategy, with genome-wide significant cis-eQTLs as primary instruments and a relaxed threshold applied only for genes with fewer than three independent SNPs. Sensitivity analyses included MR-Egger, weighted median, MR-PRESSO, MR-RAPS, and leave-one-out analyses. SMR/HEIDI testing and two-step MR mediation using 731 peripheral immune traits were also performed. RESULTS: Genetically predicted higher CXCL16 expression was associated with increased PD risk (OR = 1.115, 95% CI 1.060-1.173, p = 2.4 × 10-5), while higher FADD expression was associated with reduced PD risk (OR = 0.861, 95% CI 0.790-0.939, p = 7.1 × 10-4). CASP1 and IFI27 were nominally significant and considered exploratory. Sensitivity analyses were directionally consistent, although MR-Egger estimates were imprecise. SMR/HEIDI supported CXCL16. Exploratory mediation analysis identified 63/66 candidate immune mediators after FDR correction. CONCLUSION: These findings provide MR-based genetic evidence linking CXCL16 expression to PD risk, with exploratory mediation through peripheral immune phenotypes. The CXCL16-immune cell-PD axis warrants further experimental validation.

Humans↗

PubMed2026

The impact for causal associations between common diseases and inflammatory bowel disease: a disease-wide bidirectional Mendelian randomization study.

OBJECTIVES: Observational studies on associations between various diseases and inflammatory bowel disease (IBD) are often limited by confounding and reverse causation. We aimed to assess potential causal relationships between a wide range of diseases and IBD, including Crohn's disease (CD) and ulcerative colitis (UC). METHODS: We performed a comprehensive bidirectional Mendelian randomization (MR) analysis of 104 common diseases and IBD traits using the generalized summary-data-based MR (GSMR) approach. Genome-wide association study (GWAS) summary statistics for diseases were obtained from the MRC Integrative Epidemiology Unit, and IBD data from the International IBD Genetics Consortium. Summary-data-based MR (SMR) integrating GWAS and expression quantitative trait locus data was applied to identify pleiotropic genes associated with IBD. RESULTS: MR analyses identified 38, 34, and 52 exposures significantly associated with IBD, UC, and CD, respectively. Childhood- and adult-onset asthma showed distinct causal effects on UC and CD. Reverse MR indicated associations between IBD traits and 15 diseases, including multiple sclerosis. SMR identified RGS14 and CARD9 as pleiotropic genes linked to IBD, suggesting shared genetic mechanisms with asthma and multiple sclerosis. CONCLUSIONS: These findings provide evidence for causal links and shared immune-related genetic mechanisms underlying IBD, highlighting potential targets for future research.

Humans↗

PubMed2024

An insight into the causal relationship between sarcopenia-related traits and venous thromboembolism: A mendelian randomization study.

BACKGROUND: As a geriatric syndrome, sarcopenia has a high prevalence in the old population and represents an impaired state of health with adverse health outcomes. A strong clinical interest in its relationship with venous thromboembolism (VTE), which is a complex trait disease with a heterogeneous annual incidence rate in different countries, has emerged. The relationship between sarcopenia and venous thromboembolism has been reported in observational studies but the causality from sarcopenia to VTE remained unclarified. We aimed to assess the causal effect of sarcopenia on the risk of VTE with the two-sample Mendelian randomization (MR) method. METHODS: Two sets of single-nucleotide polymorphisms (SNPs), derived from two published genome-wide association study (GWAS) meta-analyses and genetically indexing muscle weakness and lean muscle mass separately, were pooled into inverse variance weighted (IVW), weighted median and MR-Egger analyses. RESULTS: No evidence was found for the causal effect of genetically predicted muscle weakness (IVW: OR = 0.90, 95% CI = 0.76-1.06, p = 0.217), whole body lean mass (IVW: OR = 1.01, 95% CI = 0.87-1.17, p = 0.881) and appendicular lean mass (IVW: OR = 1.13, 95% CI = 0.82-1.57, p = 0.445) on the risk of VTE. However, both genetically predicted whole-body lean mass and appendicular lean mass can causally influence diabetes mellitus (IVW of whole-body lean mass: OR = 0.87, 95% CI = 0.78-0.96, p = 0.008; IVW of appendicular lean mass: OR = 0.71, 95% CI = 0.54-0.94, p = 0.014) and hypertension (IVW of whole-body lean mass: OR = 0.92, 95% CI = 0.87-0.98, p = 0.007; IVW of appendicular lean mass: OR = 0.84, 95% CI = 0.73-0.96, p = 0.013). CONCLUSIONS: Genetically predicted sarcopenia does not causally influence VTE directly, but it might still have an indirect effect on VTE incidence via diabetes mellitus and hypertension.

Humans↗