Genetic prediction of blood metabolites mediating the relationship between gut microbiota and Alzheimer's disease: a Mendelian randomization study.

Background: Observational studies have suggested an association between gut microbiota and Alzheimer's disease (AD); however, the causal relationship remains unclear, and the role of blood metabolites in this association remains elusive. Purpose: To elucidate the causal relationship between gut microbiota and AD and to investigate whether blood metabolites serve as potential mediators. Materials and methods: Univariable Mendelian randomization (UVMR) analysis was employed to assess the causal relationship between gut microbiota and AD, while multivariable MR (MVMR) was utilized to mitigate confounding factors. Subsequently, a two-step mediation MR approach was employed to explore the role of blood metabolites as potential mediators. We primarily utilized the inverse variance-weighted method to evaluate the causal relationship between exposure and outcome, and sensitivity analyses including Contamination mixture, Maximum-likelihood, Debiased inverse-variance weighted, MR-Egger, Bayesian Weighted Mendelian randomization, and MR pleiotropy residual sum and outlier were conducted to address pleiotropy. Results: After adjustment for reverse causality and MVMR correction, class Actinobacteria (OR: 1.03, 95% CI: 1.01-1.06, p = 0.006), family Lactobacillaceae (OR: 1.03, 95% CI: 1.00-1.05, p = 0.017), genus Lachnoclostridium (OR: 1.03, 95% CI: 1.00-1.06, p = 0.019), genus Ruminiclostridium9 (OR: 0.97, 95% CI: 0.94-1.00, p = 0.027) and genus Ruminiclostridium6 (OR: 1.03, 95% CI: 1.01-1.05, p = 0.009) exhibited causal effects on AD. Moreover, 1-ribosyl-imidazoleacetate levels (-6.62%), Metabolonic lactone sulfate levels (2.90%), and Nonadecanoate (19:0) levels (-12.17%) mediated the total genetic predictive effects of class Actinobacteria on AD risk. Similarly, 2-stearoyl-GPE (18:0) levels (-9.87%), Octadecanedioylcarnitine (C18-DC) levels (4.44%), 1-(1-enyl-stearoyl)-2-oleoyl-GPE (p-18:0/18:1) levels (38.66%), and X-23639 levels (13.28%) respectively mediated the total genetic predictive effects of family Lactobacillaceae on AD risk. Furthermore, Hexadecanedioate (C16-DC) levels (5.45%) mediated the total genetic predictive effects of genus Ruminiclostridium 6 on AD risk; Indole-3-carboxylate levels (13.91%), X-13431 levels (7.08%), Alpha-ketoglutarate to succinate ratio (-13.91%), 3-phosphoglycerate to glycerate ratio (15.27%), and Succinate to proline ratio (-14.64%) respectively mediated the total genetic predictive effects of genus Ruminiclostridium 9 on AD risk. Conclusion: Our mediation MR analysis provides genetic evidence suggesting the potential mediating role of blood metabolites in the causal relationship between gut microbiota and AD. Further large-scale randomized controlled trials are warranted to validate the role of blood metabolites in the specific mechanisms by which gut microbiota influence AD.

Physical activity, sedentary behavior, and risk of sepsis: a two-sample mendelian randomization study.

Objective: This investigation aimed to explore the potential causal relationship between physical activity, sedentary behavior and the risk of sepsis. Methods: Using a two-sample Mendelian randomization approach, this study evaluated the association between physical activity (including moderate to vigorous physical activity [MVPA], vigorous physical activity [VPA], and accelerometer assessed physical activity) and sedentary behaviors (including television watching, computer use, and driving) with the risk of sepsis. This assessment was based on whole-genome association study data from the UK Biobank and the FinnGen database. Causal inferences were estimated using inverse variance-weighted, weighted median, and MR-Egger methods. Sensitivity analyses were performed using Cochran's Q test, the MR-Egger intercept test, and the leave-one-out method. Results: The risk of sepsis was significantly inversely associated with genetically predicted MVPA (odds ratio [OR] 0.47, 95% confidence interval [CI] 0.24-0.93, P = 0.0296) and VPA alone (OR 0.19, 95% CI 0.04-0.87, P = 0.0324). Conversely, prolonged driving time showed a significant positive association with the risk of sepsis (OR 3.99, 95% CI 1.40-11.40, P = 0.0097). Conclusion: This study provides preliminary evidence of a causal relationship between MVPA and VPA and a reduced risk of sepsis, while prolonged sedentary behaviors such as driving are positively associated with an increased risk of sepsis. These findings provided essential scientific evidence for the development of effective sepsis prevention strategies.

Identifying the plasma metabolome responsible for mediating immune cell action in severe COVID-19: a Mendelian randomization investigation.

Introduction: The immune response regulates the severity of COVID-19 (sCOVID-19). This study examined the cause-and-effect relationship between immune cell traits (ICTs) and the risk of severe COVID-19. Additionally, we discovered the potential role of plasma metabolome in modulating this risk. Methods: Employing data from a genome-wide association study (GWAS), we conducted a two-sample Mendelian randomization (MR) assessment of 731 genetic ICTs and sCOVID-19 (5,101 cases, 1,383,241 controls) incidence. The MR analysis was utilized to further quantitate the degree of plasma metabolome-mediated regulation of immune traits in sCOVID-19. Results: The inverse variance weighted method recognized 2 plasma metabolites (PMs) responsible for casual associations between immune cells and sCOVID-19 risk. These included Tridecenedioate (C13:1-DC) which regulated the association between CD27 on IgD- CD38br (OR 0.804, 95% CI 0.699-0.925, p = 0.002) and sCOVID-19 risk (mediated proportion: 18.7%); arginine to citrulline ratio which controlled the relationship of CD39 on monocyte (OR 1.053, 95% CI 1.013-1.094, p = 0.009) with sCOVID-19 risk (mediated proportion: -7.11%). No strong evidence that genetically predicted sCOVID-19 influenced the aforementioned immune traits. Conclusion: In this study, we have successfully identified a cause-and-effect relationship between certain ICTs, PMs, and the likelihood of contracting severe COVID-19. Our findings can potentially improve the accuracy of COVID-19 prognostic evaluation and provide valuable insights into the underlying mechanisms of the disease.

Exploring the genetic causal relationship between physical activity and migraine in European population based on Mendelian randomization analysis.

Background: Previous studies have shown a connection between physical activity and migraines, but they don't prove a cause-and-effect relationship due to potential biases in observational methods. Methods: Utilizing accelerometer-measured physical activity data from a cohort of 377,234 participants in the UK Biobank and information from 599,356 European migraine patients (including 48,975 cases and 550,381 controls) obtained from 24 cohorts, we performed a bidirectional Mendelian randomization analysis to investigate the genetic bidirectional causal relationship between accelerometer-measured physical activity and migraines. Results: Research findings indicated a slight negative genetic correlation between "average acceleration" physical activity (rg = -0.091, p = 0.011), overall physical activity (rg = -0.081, p = 0.017), and migraine. Nevertheless, no shared genetic components were observed between migraine and "fraction of accelerations > 425 mg" of physical activity (rg = -0.124, p = 0.076). The study results also demonstrated a lack of genetic bidirectional causality between accelerometer-measured physical activity and migraine ("average acceleration", OR = 1.002, 95% CI 0.975-1.031, p = 0.855, "fraction of accelerations > 425 mg", OR = 1.127, 95% CI 0.802-1.583, p = 0.488, overall physical activity, OR = 0.961, 95% CI 0.713-1.296, p = 0.799), and vice versa. Additionally, this lack of causal association persists even after adjusting for obesity (OR = 1.005, p = 0.578), education (OR = 1.019, p = 0.143), and depression (OR = 1.005, p = 0.847), either separately or simultaneously. Conclusion: The Mendelian randomization results based on genetic data do not provide support for a causal association between physical activity and migraine.

Gut microbiota metabolic pathways: Key players in knee osteoarthritis development.

OBJECTIVE: To confirm the causality of gut microbiota pathway abundance and knee osteoarthritis (KOA). METHODS: Microbial metabolic pathways were taken as exposures, with data from the Dutch Microbiome Project (DMP). Data on KOA from the UK Biobank were utilized as endpoints. In addition, we extracted significant and independent single nucleotide polymorphisms as instrumental variables. Two-sample Mendelian randomization (MR) analysis was applied to explore the causal relationship between gut microbiota pathway abundance and KOA, and MR-Egger and weighted median were used as additional validation of the MR results. Meanwhile, Cochran Q, MR-Egger intercept, MR-PRESSO, and leave-one-out were used to perform sensitivity analyses on the MR results. RESULTS: MR results showed that enterobactin biosynthesis, diacylglycerol biosynthesis I, Clostridium acetobutylicum acidogenic fermentation, glyoxylate bypass and tricarboxylic acid cycle were the risk factors for KOA. (OR = 1.13,95%CI = 1.04-1.23;OR = 1.12,95%CI = 1.04-1.20;OR = 1.14,95%CI = 1.04-1.26; OR = 1.06,95%CI = 1.00-1.12) However, adenosylcobalamin salvage from cobinamide I, hexitol fermentation to lactate formate ethanol and acetate, purine nucleotides degradation II aerobic, L tryptophan biosynthesis and inosine 5 phosphate biosynthesis III pathway showed significant protection against KOA. (OR = 0.93,95%CI = 0.86-1.00;OR = 0.94,95%CI = 0.88-1.00;OR = 0.91,95%CI = 0.86-0.97;OR = 0.95,95%CI = 0.92-0.99; OR = 0.91, 95%CI = 0.85-0.98) Further multiplicity and sensitivity analyses demonstrated the robustness of the results. CONCLUSION: Our study identified specific metabolic pathways in gut microbiota that promote or inhibit KOA, which provides the most substantial evidence-based medical evidence for the pathogenesis and prevention of KOA.

Exploring the complex link between obesity and intelligence: Evidence from systematic review, updated meta-analysis, and Mendelian randomization.

Obesity is a major public health concern associated with a higher risk of various comorbidities. Some studies have explored the impact of obesity on cognitive function and, conversely, how lower intelligence might increase the risk of later obesity. The aim of this study is to analyze a complex relationship between body mass index (BMI) and intelligence quotient (IQ), employing a comprehensive approach, including a systematic review, meta-analysis, and Mendelian randomization (MR). We extracted the data from Medline and Embase to identify relevant studies published since June 22, 2009. MR analysis relied on genetic databases such as the Genome-Wide Association Study (GWAS) and the Genetic Investigation of Anthropometric Traits (GIANT) to explore potential causal relationships. The systematic review and meta-analysis encompassed 34 and 17 studies, respectively. They revealed a substantial correlation between obesity and reduced IQ, particularly notable among school-age children (mean difference -5.26; 95% CI: -7.44 to -3.09). Notably, within the IQ subgroup, verbal IQ also exhibited a significant association with a mean difference of -7.73 (95% CI: -14.70 to -0.77) in school-age children. In contrast, the MR did not unveil a significant causal relationship between BMI and IQ, both in childhood and adulthood. This comprehensive analysis underscores a significant correlation between BMI and IQ, particularly in school-age children. However, the MR analysis implies a potentially weaker causal relationship. Future large-scale cohort studies should address potential confounding factors to provide further insights into the BMI-IQ relationship.

Mediating role of inflammatory biomarkers in the causal effect of body composition on glycaemic traits and type 2 diabetes.

OBJECTIVE: The aim was to investigate the mediating role of inflammatory biomarkers in the causal effect of body composition on glycaemic traits and type 2 diabetes. METHODS: A retrospective observational study and a Mendelian randomization (MR) study were used. Observational analyses were performed using data from 4717 Chinese children and adolescents aged 6-18 years who underwent dual-energy X-ray absorptiometry for body composition. MR analyses were based on summary statistics from UK Biobank, deCODE2021, Meta-Analysis of Glucose and Insulin-Related Traits Consortium (MAGIC) and other large consortiums. Inflammatory biomarkers included leptin, adiponectin, osteocalcin, fibroblast growth factor 23 (FGF23) and parathyroid hormone (PTH). RESULTS: In a retrospective observational study, increased fat mass had a positive effect on homeostasis model assessment of insulin resistance (HOMA-IR) and homeostasis model assessment of pancreatic beta cell function (HOMA-ß) through FGF23, whereas fat-free mass produced the opposite effects. PTH and osteocalcin played significant roles in the association of fat mass and fat-free mass with fasting glucose, fasting insulin and HOMA-IR (all p < 0.05). Mediation MR results indicated that childhood body mass index affected glycaemic traits through leptin and adiponectin. There existed a causal effect of fat-free mass on type 2 diabetes via FGF23 (indirect effect: OR [odds ratio]: 1.14 [95% CI, confidence interval: 1.01-1.28]) and adiponectin (OR: 0.85 [95% CI: 0.77-0.93]). Leptin mediated the causal association of fat mass (indirect effect: ß: -0.05 [95% CI: -0.07, -0.02]) and fat-free mass (ß: 0.03 [95% CI: 0.01, 0.04]) with fasting glucose. CONCLUSIONS: Our findings suggest that different body compositions have differential influences on glycaemic traits and type 2 diabetes through distinct inflammatory biomarkers. The findings may be helpful in tailoring management of body composition based on inflammatory biomarkers with different glycaemic statuses.

Causal relationship between key genes and metabolic dysfunction-associated fatty liver disease risk mediated by immune cells: A Mendelian randomization and mediation analysis.

AIM: Non-invasive diagnostics for metabolic dysfunction-associated fatty liver disease (MAFLD) remain challenging. We aimed to identify novel key genes as non-invasive biomarkers for MAFLD, elucidate causal relationships between biomarkers and MAFLD and determine the role of immune cells as potential mediators. MATERIALS AND METHODS: Utilizing published transcriptome data of patients with biopsy-proven MAFLD, we applied linear models for microarray data, least absolute shrinkage and selector operation (LASSO) regressions and receiver operating characteristic (ROC) curve analyses to identify and validate biomarkers for MAFLD. Using the expression quantitative trait loci database and a cohort of 778 614 Europeans, we used Mendelian randomization to analyse the causal relationships between key biomarkers and MAFLD. Additionally, mediation analysis was performed to examine the involvement of 731 immunophenotypes in these relationships. RESULTS: We identified 31 differentially expressed genes, and LASSO regression showed three hub genes, IGFBP2, PEG10, and P4HA1, with area under the receiver operating characteristic (AUROC) curve of 0.807, 0.772 and 0.791, respectively, for identifying MAFLD. The model of these three genes had an AUROC of 0.959 and 0.800 in the development and validation data sets, respectively. This model was also validated using serum-based enzyme-linked immunosorbent assay data from MAFLD patients and control subjects (AUROC: 0.819, 95% confidence interval: 0.736-0.902). PEG10 was associated with an increased MAFLD risk (odds ratio = 1.106, p = 0.032) via inverse variance-weighted analysis, and about 30% of this risk was mediated by the percentage of CD11c + CD62L- monocytes. CONCLUSIONS: The MAFLD panels have good diagnostic accuracy, and the causal link between PEG10 and MAFLD was mediated by the percentage of CD11c + CD62L- monocytes.

Association between interleukin-12 p40 subunit and risk of primary Sjögren's syndrome: a Mendelian randomization study.

OBJECTIVES: Interleukin-12 (IL-12) signalling was proposed in the immunopathogenesis of primary Sjögren's disease. The efficacy of therapies targeting this pathway is currently unclear. Herein, we investigated the associations between circulating proteins involved in the IL-12 and IL-23 signalling pathways on primary Sjögren's disease using mendelian randomization. METHODS: We selected SNPs from protein quantitative trait loci of IL12A, IL12B, IL12Rß1, IL12Rß2, and IL23R to examine the association between alterations in their levels and risk of primary Sjögren's disease. Genetic association data for proteins were taken from studies ranging from 3,301-54 306 in sample size, and from 3,232 cases of primary Sjögren's disease and 17 481 controls. The Wald ratio or inverse variance weighted methods estimated causal effects. We applied colocalization and pleiotropy-robust methods as sensitivity analyses for confounding. RESULTS: There was a negative association between genetically predicted IL-12p40 (encoded by IL12B) and primary Sjögren's disease. In the two independent exposure datasets odds ratio (OR) 0.79 (95% confidence interval [CI] 0.68-0.93; P-value = 0.004) and OR 0.86 (95% CI 0.78-0.95; P-value = 0.003) per standard deviation decrease in genetically predicted IL-12p40. Neither IL-12Rß2 and IL-23R met the threshold P-value after MR analyses (P-value < 0.01) for colocalization assessment. No variants for the IL12A gene met prerequisite thresholds for weak instrument bias. CONCLUSION: This study provides genetic evidence that IL-12p40 has a causal role in primary Sjögren's disease pathogenesis. Our data suggest that decreasing levels of IL-12p40 may be deleterious. We would not suggest selecting this drug target as a therapeutic option.

Genetic effect of thyroid function-related diseases on acute respiratory distress syndrome: a Mendelian randomization study.

BACKGROUND: Previous studies have shown an association between acute respiratory distress syndrome (ARDS) and thyroid function. However, their causal relationship remains unspecified. Therefore, this study aims to explore the causal relationship between ARDS and thyroid function-related diseases with Mendelian Randomization (MR) analysis. METHODS: ARDS dataset finn-b-J10_ARDS, finn-b-E4_THYROID dataset of disorders of the thyroid gland (DTG) and finn-b-E4_HYTHYNAS of hypothyroidism were acquired from public database. In univariate MR (UVMR), causal effects between DTG, hypothyroidism and ARDS were investigated using 5 types of algorithms, and reliability was validated by sensitivity analysis. Moreover, multivariate MR (MVMR), enrichment and interaction network analyses of genes corresponding to SNPs of DTG and hypothyroidism were carried out. Significant level was chosen as p<0.05. RESULTS: UVMR identified DTG and hypothyroidism (P < 0.05, OR > 1) as risk factors, and were causally related to ARDS. Reliability of UVMR results was confirmed through sensitivity analysis, and results were stable and reliable. However, DTG and hypothyroidism had no effect on ARDS in MVMR, possibly because these factors had independent effects on ARDS. Ultimately, 96 and 113 genes corresponding to SNPs of DTG and hypothyroidism were found closely related to immune-related pathways. CONCLUSIONS: UVMR and MVMR analysis revealed a causal connection between DTG and hypothyroidism as risk factors with ARDS, providing robust evidence for investigation into relationship of hypothyroidism on ARDS and between DTG and ARDS.

Association of hidradenitis suppurativa (HS) with waist circumference: A bidirectional two-sample Mendelian randomization study of HS with metabolic syndrome.

Observational studies have suggested an associations between hidradenitis suppurativa (HS) and metabolic syndrome (MetS) and its components. However, it remains unclear whether the relationship is causal or not. Our study aimed to investigate the causal association of HS with MetS and its components. We performed a bidirectional, two-sample Mendelian randomization study using summary-level data from the most comprehensive genome-wide association studies of HS (n = 362 071), MetS (n = 291 107), waist circumference (n = 462 166), hypertension (n = 463 010) fasting blood glucose (FBG, n = 200 622), triglycerides (n = 441 016), and high-density lipoprotein cholesterol (HDL-C, n = 403 943). Genetic instrumental variables were constructed by identifying single nucleotide polymorphisms associated with the corresponding factors. The random-effects inverse-variance weighted method was applied as the primary method. The results showed that genetically predicted HS was positively associated with waist circumference risk in both directions. High waist circumference increased the risk of HS (odds ratio [OR] 4.147; 95% confidence interval [CI] 2.610-6.590; p = 1.746 × 10-9). In addition, HS was also affected by waist circumference (OR 1.009; 95% CI 1.006-1.012; p = 3.08 × 10-7). No causal relationships were found between HS and MetS or its components other than waist circumference. The findings highlight the importance of early intervention for obesity in HS patients. Further studies are needed to determine the pathophysiology of HS associated with MetS and its components.

Genome-Wide Identification of Cell Type-Specific Susceptibility Genes for SLE Through the Analysis of RNA Modification-Associated SNPs.

INTRODUCTION: This study aimed to elucidate the functional genes associated with systemic lupus erythematosus (SLE) in various cell types through the utilization of RNAm-SNPs. METHODS: Utilizing large-scale genetic data, we identified associations between RNAm-SNPs and SLE. The association between RNAm-SNPs and bulk and single-cell mRNA expression (eQTL) and protein levels (pQTL) were examined. Mendelian randomization and differential expression analyses were conducted to explore the links between gene expression, protein levels, and SLE. RESULTS: We identified 41 RNAm-SNPs that were significantly associated with SLE. The GWAS signals exhibited notable enrichment in m6A-SNPs and m7G-SNPs. These RNAm-SNPs showed both eQTL and pQTL effects. In our single-cell analysis, 16 RNAm-SNPs exhibited associations with gene expression levels across 13 distinct cell types, including HLA-A, HLA-B, HLA-C, HLA-DQA1, HLA-DQB1, HLA-DRB1 and IRF7. We identified 58 noteworthy associations between the expression levels of 20 genes and SLE across 12 distinct immune cell types. Notably, HLA-DQB1, HLA-DRB1 and IRF7 exhibited abnormalities in CD8+ T cells, IRF7 displayed abnormal expression in CD4+ T cells, while HLA-DRB1 and IRF7 were also distinctly perturbed in natural killer cells. DISCUSSION: This study advances our understanding of the genetic basis of SLE by highlighting the significance of RNAm-SNPs and immune cell gene expression in SLE.

A wrap-around movement path randomization method to distinguish social and spatial drivers of animal interactions.

Studying the spatial-social interface requires tools that distinguish between social and spatial drivers of interactions. Testing hypotheses about the factors determining animal interactions often involves comparing observed interactions with reference or 'null' models. One approach to accounting for spatial drivers of social interactions in reference models is randomizing animal movement paths to decouple spatial and social phenotypes while maintaining environmental effects on movements. Here, we update a reference model that detects social attraction above the effect of spatial constraints. We explore the use of our 'wrap-around' method and compare its performance to the previous approach using agent-based simulations. The wrap-around method provides reference models that are more similar to the original tracking data, while still distinguishing between social and spatial drivers. Furthermore, the wrap-around approach results in fewer false-positives than its predecessor, especially when animals do not return to one place each night but change movement foci, either locally or directionally. Finally, we show that interactions among GPS-tracked griffon vultures (Gyps fulvus) emerge from social attraction rather than from spatial constraints on their movements. We conclude by highlighting the biological situations in which the updated method might be most suitable for testing hypotheses about the underlying causes of social interactions. This article is part of the theme issue 'The spatial-social interface: a theoretical and empirical integration'.

Does Gastroesophageal Reflux Disease Increase the Risk of Sepsis and Its 28-day Mortality? A Causal Study Using a Mendelian Randomization Approach.

BACKGROUND: Gastroesophageal reflux disease (GERD) is a prevalent gastrointestinal disorder. Recent studies indicate that GERD may exert systemic effects, potentially elevating the risk of severe infections, including sepsis. Nevertheless, the causal relationship between GERD and sepsis, as well as sepsis-related 28-day mortality, remains uncertain. AIM: The aim of this study is to investigate the causal relationship between GERD and the risk of sepsis, including 28-day mortality of sepsis. METHODS: This study utilized a two-sample Mendelian Randomization (MR) approach to analyze data from publicly available genome-wide association studies (GWAS) databases ( https://gwas.mrcieu.ac.uk/ ). The analysis comprised 129,080 cases and 473,524 controls for GERD; 11,643 patients and 474,841 controls for sepsis; and 1,896 patients and 484,588 controls for 28-day mortality from sepsis. The objective was to evaluate the causal impact of GERD on the risk of sepsis and 28-day sepsis mortality. Genetic variation data pertinent to GERD were obtained from the most recent genome-wide association studies (GWAS). The primary analysis employed the Inverse Variance Weighted (IVW) method. Sensitivity and pleiotropy analyses were performed to validate the robustness of the findings. RESULTS: MR analysis revealed a notable link between genetically predicted GERD and increased sepsis risk (odds ratio [OR] 1.37, 95% confidence interval [CI] 1.24-1.52; p = 2.79 × 10-9). Moreover, GERD correlated with elevated 28-day mortality of sepsis (OR 1.44, 95% CI 1.11-1.85; p = 5.34 × 10-3). These results remained consistent throughout various sensitivity analyses, indicating their resilience against potential pleiotropy and other biases. CONCLUSION: This study indicates that genetic predisposition to GERD may be linked to an elevated risk of sepsis and its associated 28-day mortality. However, the study does not establish a direct causal relationship for GERD itself, nor does it assess the impact of GERD treatment. Further research is needed to explore the underlying mechanisms and potential therapeutic interventions involved.

Active longevity and aging: dissecting the impacts of physical and sedentary behaviors on longevity and age acceleration.

BACKGROUND: To examine the associations of physical activity (PA) and sedentary behavior (SB) with longevity and age acceleration (AA) using observational and Mendelian randomization (MR) studies, and quantify the mediating effects of lipids. METHODS: In Guangzhou Biobank Cohort Study (GBCS), PA and SB were assessed by the Chinese Version of the International Physical Activity Questionnaire. Longevity was defined as participants whose age at follow-up or at death was at or above the 90th age percentile. AA was defined as the residual resulting from a linear model that regressed phenotypic age against chronological age. Linear regression and Poisson regression with robust error variance were used to assess the associations of total and specific PA in different intensities, and SB with AA and longevity, yielding ßs or relative risks (RRs) and 95% confidence intervals (CIs). Two-sample MR was conducted to examine the causal effects. Mediation analysis was used to assess the mediating effects of lipids. RESULTS: Of 20,924 participants aged 50 + years in GBCS, during an average follow-up of 15.0 years, compared with low PA, moderate and high PA were associated with higher likelihood of longevity (RR (95% CI): 1.56 (1.16, 2.11), 1.66 (1.24, 2.21), respectively), and also cross-sectionally associated with lower AA (ß (95% CI): -1.43 (-2.41, -0.45), -2.09 (-3.06, -1.11) years, respectively). Higher levels of moderate PA (MPA) were associated with higher likelihood of longevity and lower AA, whereas vigorous PA (VPA) showed opposite effects. The association of PA with longevity observed in GBCS was mediated by low-density lipoprotein cholesterol (LDL-C) by 8.23% (95% CI: 3.58-39.61%), while the association with AA was mediated through LDL-C, triglycerides and total cholesterol by 5.13% (3.94-7.30%), 7.81% (5.98-11.17%), and 3.37% (2.59-4.80%), respectively. Additionally, in two-sample MR, SB was positively associated with AA (ß (95% CI): 1.02 (0.67, 1.36) years). CONCLUSIONS: PA showed protective effects on longevity and AA, with the effects being partly mediated through lipids. Conversely, SB had a detrimental impact on AA. MPA was associated with higher likelihood of longevity and reduced AA, whereas VPA showed adverse effects. Our findings reinforce the recommendation of "sit less and move more" to promote healthy longevity, and highlight the potential risks associated with VPA in the elderly.

Causality between autoimmune diseases and breast cancer: a two-sample Mendelian randomization study in a European population.

BACKGROUND: The incidence of autoimmune diseases and breast cancer is significantly higher in women compared to men. Previous observational studies have not conclusively determined the relationship between these two conditions. This study utilizes the Mendelian randomization approach to investigate the genetic association between autoimmune diseases and breast cancer. METHOD: Two-sample Mendelian randomization was conducted on a European population using the GWAS database. The inverse variance-weighted method served as the primary analytical approach. The MR-PRESSO test was applied to detect horizontal pleiotropy. To ensure result robustness, the FDR correction method was used. RESULT: The study revealed that Sjögren's syndrome lowers the overall risk of breast cancer (OR 0.96, 95% CI [0.93-0.99], p = 0.011). Idiopathic inflammatory myopathy shows a protective effect against overall breast cancer (OR 0.98, 95% CI [0.97-0.99], p = 0.035). An association was identified between rheumatoid arthritis and overall breast cancer (OR 0.98, 95% CI [0.96-1.00], p = 0.050). No causal link was found between systemic lupus erythematosus, systemic sclerosis, and overall breast cancer. The study also suggests that Sjögren's syndrome, rheumatoid arthritis, and idiopathic inflammatory myopathy might reduce the risk of developing HER + breast cancer. Specifically, Sjögren's syndrome (OR = 0.90, 95% CI [0.83-0.98], p = 0.02), rheumatoid arthritis (OR = 0.94, 95% CI [0.91-0.98], p = 0.006), and idiopathic inflammatory myopathy (OR = 0.96, 95% CI [0.93-0.99], p = 0.036). Additionally, systemic lupus erythematosus was found to lower the risk of HER- breast cancer (OR = 0.95, 95% CI [0.91-0.99], p = 0.046). The study did not establish a causal relationship between these five autoimmune diseases and ER + or ER- breast cancer. CONCLUSION: This study found that autoimmune diseases may act as protective factors against breast cancer risk.

Female genital prolapse and risk of psychiatric disorders: A two-sample Mendelian randomization analysis.

BACKGROUND: There is a growing body of evidence suggests a strong link between female genital prolapse (FGP) and mental health. However, the causal relationship between FGP and psychological disorders remains unclear. OBJECTIVES: Bidirectional Mendelian Randomization (MR) analysis has been applied to investigate the potential impact of FGP on the risk of seven common psychiatric disorders. METHODS: The two-sample MR analysis was conducted using genetic instruments such as Inverse variance weighted (IVW), MR Egger, weighted median, simple mode, and weighted mode from the genome-wide association study (GWAS) summary data in European populations. In addition, the Cochrane's Q test, MR-Egger intercept test, MR pleiotropy residual sum and outliers (MR-PRESSO) test and leave-one-out analysis were employed to assess the sensitivity and heterogeneity. RESULTS: The MR results revealed that FGP exhibited a potential marginal protective effect on bipolar disorder (BD) (odds ratio(OR) = 0.92, 95%confidence interval (95%CI: 0.85-0.99, P = 0.03) as well as schizophrenia(OR = 0.91, 95%CI:0.85-0.98, P = 0.01). Nevertheless, there was no causal correlation between genetically predicted FGP and obsessive compulsive disorder (OCD) (OR = 0.98, 95%CI:0.80-1.20, P = 0.84),depression (broad) (OR = 1.00, 95%CI:0.99-1.01, P = 0.76), major depression(OR = 0.98, 95%CI:0.94-1.03, P = 0.43), anxiety disorders (OR = 1.00, 95%CI:0.94-1.07,P = 0.97) and post-traumatic stress disorder(PTSD) (OR = 1.18, 95%CI:0.88-1.57,P = 0.27),respectively. In addition, BD was found to have a potential significant influence on FGP in the inverse MR analysis (OR = 0.83, 95%CI:0.72-0.97, P = 0.02). No significant heterogeneity or horizontal pleiotropy detected, and the results were deemed stable based on sensitivity analysis and leave-one-out test . LIMITATIONS: There are shortcomings such as data limitations, population bias, potential pleiotropy, and stratified analysis. CONCLUSIONS: While there is potential causal relationship between FGP and BD or schizophrenia, it does not exhibit any correction with OCD, depression (broad), major depression, anxiety disorders and PTSD among European populations.

Proteome-wide mendelian randomization identifies therapeutic targets for nephrolithiasis.

Kidney Stone Disease (KSD) constitutes a multifaceted disorder, emerging from a confluence of environmental and genetic determinants, and is characterized by a high frequency of occurrence and recurrence. Our objective is to elucidate potential causative proteins and identify prospective pharmacological targets within the context of KSD. This investigation harnessed the unparalleled breadth of plasma protein and KSD pooled genome-wide association study (GWAS) data, sourced from the United Kingdom Biobank Pharma Proteomics Project (UKBPPP) and the FinnGen database version R10. Through Mendelian randomization analysis, proteins exhibiting a causal influence on KSD were pinpointed. Subsequent co-localization analyses affirmed the stability of these findings, while enrichment analyses evaluated their potential for pharmacological intervention. Culminating the study, a phenome-wide association study (PheWAS) was executed, encompassing all phenotypes (2408 phenotypes) catalogued in the FinnGen database version R10. Our MR analysis identified a significant association between elevated plasma levels of proteins FKBPL, ITIH3, and SERPINC1 and increased risk of KSD based on genetic predictors. Conversely, proteins CACYBP, DAG1, ITIH1, and SEMA6C showed a protective effect against KSD, documented with statistical significance (PFDR<0.05). Co-localization analysis confirmed these seven proteins share genetic variants with KSD, signaling a shared genetic basis (PPH3 + PPH4 > 0.8). Enrichment analysis revealed key pathways including hyaluronan metabolism, collagen-rich extracellular matrix, and serine-type endopeptidase inhibition. Additionally, our PheWAS connected the associated proteins with 356 distinct diseases (PFDR<0.05), highlighting intricate disease interrelations. In conclusion, our research elucidated a causal nexus between seven plasma proteins and KSD, enriching our grasp of prospective therapeutic targets.

The impact of sex hormones on metabolic syndrome: univariable and multivariable Mendelian randomization studies.

BACKGROUND: Observational studies have found associations between sex hormones and metabolic syndrome(Mets), but the causal relationships remains unclear. This study utilizes univariable and multivariable Mendelian randomization (MR) to elucidate the associations between sex hormones (including sex hormone-binding globulin(SHBG), estradiol(E2), testosterone(T)) and Mets and its subtypes (including waist circumference(WC), fasting blood glucose(FBG), high blood pressure(HBP), high-density lipoprotein(HDL-C), triglycerides(TG)). METHODS: We utilized summary data from large-scale genome-wide association studies. Univariable Mendelian randomization (UMVMR) analysis was primarily conducted using the inverse variance weighted method (IVW), with secondary analyses employing the weighted median, MR-Egger regression, simple mode method, and weighted mode method. Subsequently, multivariable Mendelian randomization (MVMR) was employed to assess the causal relationships between SHBG, T, E2, and MetS and its components: WC, FPG, HBP, HDL-C, and TG. Sensitivity analyses were conducted to assess result reliability. RESULTS: Genetically predicted SHBG was significantly negatively associated with MetS (UMVMR: ß=-0.72; 95% CI = 0.41 to 0.57; P = 1.28e-17; MVMR: ß=-0.60; 95% CI=-0.83 to -0.38; P < 0.001). Positive causal relationships were observed between SHBG and WC(MVMR: ß = 0.10; 95% CI = 0.03 to 0.17; P = 0.01) and HDL-C (MVMR: ß = 0.41; 95% CI = 0.21 to 0.60; P < 0.001), while negative causal relationships were found between SHBG and HBP (MVMR: ß=-0.02; 95% CI=-0.04 to -0.00; P = 0.02), TG (MVMR: ß=-0.48; 95% CI=-0.70 to -0.26; P < 0.001). Genetically predicted E2 exhibited a negative association with TG (MVMR: ß=-1.49; 95% CI=-2.48 to -0.50; P = 0.003). Genetically predicted T was negatively associated with TG (MVMR: ß=-0.36; 95% CI=-0.71 to -0.00; P = 0.049) and WC (MVMR: ß=-0.13; 95% CI=-0.24 to -0.02; P = 0.02), with inconsistent sensitivity analyses. Additionally, No other causal associations were found. CONCLUSION: Our study indicates that SHBG is a protective factor for MetS, potentially delaying its onset and progression through improvements in HBP and TG. Furthermore, T and E2 may improve TG levels, with T also reducing WC levels. Importantly, our study provides new insights for the prevention and treatment of MetS.

Causal effects of female reproductive features on nonalcoholic fatty liver disease: A mendelian randomization study.

BACKGROUND AND AIMS: Epidemiological evidence on the associations between female reproductive features and nonalcoholic fatty liver disease (NAFLD) is conflicting. To explore their causalities, we conducted a Mendelian randomization (MR) study. METHODS: Summary-level data were obtained, and univariable MR was performed to explore the causalities between female reproductive features and NAFLD. And we performed multivariable MR and MR mediation analysis to explore the mediation effects of educational attainment (EA) and body mass index (BMI) for these associations. Sensitivity analyses were performed to evaluate pleiotropy and heterogeneity. RESULTS: There were causal effects of age at menarche (AAMA) (odds ratio [OR]: 0.817, 95% confidence interval [CI]: 0.736-0.907, per year-increase), age at first birth (AFB) (OR: 0.851, 95%CI: 0.791-0.926, per year-increase) and age at first sexual intercourse (AFS) (OR: 0.676, 95%CI: 0.511-0.896, per standard deviation-increase) on NAFLD risk. Besides, the causal effects were also observed on NAFLD phenotypes including liver fat content (LFC) and alanine aminotransferase (ALT). Further mediation analysis showed that BMI mediated partial proportion of effects of AAMA and AFS on NAFLD/ALT, AFB on NAFLD/LFC/ALT, while EA mediated partial proportion of effects of AFB on NAFLD/LFC/ALT, and AFS on NAFLD/ALT. CONCLUSIONS: This study provided convincing evidence that early AAMA, AFB, and AFS were risk factors for NAFLD. Reproductive health education, obesity management, and education spread might be the beneficial strategies for NAFLD prevention.