Bidirectional two-sample Mendelian randomization analysis identifies causal associations between relative carbohydrate intake and depression

Identification of mitochondrial-related causal genes for major depression disorder via integrating multi-omics

CONTEXT

Mitochondria dysfunction plays a pivotal role in major depressive disorder (MDD), but the causal link between mitochondria dysfunction and MDD remains unclear.

AIMS

This study aimed to explore the causal effects of mitochondrial-related genes (MRGs) on MDD by integrating multi-omics data.

METHODS

Summary statistics of DNA methylation, gene expression, and protein for MRGs were obtained from the corresponding quantitative trait loci in European ancestry individuals. GWAS summary statistics for MDD were sourced from the Psychiatric Genomics Consortium (PGC, discovery) and FinnGen R10 study (replication). Summary-data-based Mendelian Randomization (SMR) was performed to assess the association between DNA methylation, gene expression, and protein abundances of MRGs with the risk of MDD. Colocalization analysis was employed to assess the potential shared genetic variants between MRGs and MDD. Two-sample MR was conducted to assess the sensitivity of the SMR results. Single-nucleus RNA-sequencing (snRNA-seq) and bulk RNA-seq data were used to explore the candidate MRG expression.

RESULTS

We identified methylation levels of PPTC7 (cg08752433) and methylation levels of VRS2 (cg07945879, cg14935711, cg00244776, cg15848685, cg12457901, cg16958594) associated with a decreased risk of MDD. Conversely, the methylation levels of VRS2 (cg26784891, cg05853013, cg04966294) and MRPL46 (cg00200755) were associated with increased risk of MDD. High expression of COQ8A and TRMT10C were associated with an increased risk of MDD. Notably, COQ8A was predominantly expressed in both inhibitory and excitatory neurons in MDD patients.

CONCLUSION

This study established a causal relationship between mitochondrial dysfunction and MDD, identifying candidate MRGs, and providing potential diagnostic and therapeutic targets for MDD.

The association of Dietary Quality Index-International (DQII) score with anxiety and depression: Results of a population-based study

BACKGROUND

Recent evidence indicates a relationship between diet quality and prevalent psychiatric disorders, though, the nature of this association remains unclear. This study aimed to investigate the association between the Dietary Quality Index-International (DQII) score and the severity of depression and anxiety.

METHODS

This cross-sectional research involved 6472 individuals aged 35-65 from the Mashhad stroke and heart atherosclerotic disorder (MASHAD) study. Dietary intake was assessed using a validated food frequency questionnaire (FFQ), and dietary quality was evaluated using the DQI-I score. The severity scores of depression and anxiety were measured through the Beck Anxiety Inventory (BAI) and Beck Depression Inventory (BDI).

RESULTS

Participants in the highest tertile of DQI-I had lower anxiety and depression severity scores than those in lower tertiles (P < 0.001). After adjusting for confounders, the association remained significant only for depression score (OR = 0.85; 95 % CI: 0.73-0.98; p = 0.02). Among DQI-I components, only overall balance was significantly associated with depression score (OR = 0.86; 95 % CI: 0.75-1.00; p = 0.04). Higher variety and adequacy scores were linked to lower odds of anxiety score (OR = 0.75; 95 % CI: 0.61-0.93; p < 0.01 and OR = 0.79; 95 % CI: 0.66-0.96; p = 0.02).

LIMITATIONS

The cross-sectional design restricts causal inference, FFQs introduce recall bias, and unmeasured confounding remains a possibility.

CONCLUSION

Individuals in the highest DQI-I tertile had lower odds of severe depression score. Overall balance correlated significantly with depression severity score, while higher variety and adequacy scores were linked to reduced severe anxiety score.

Effects of micronutrients on neurodevelopmental disorders through the mediation of brain structure and function: A two-step Mendelian randomization analysis

The physiological functions of micronutrients in neurodevelopment are well documented, but their protective effects on neurodevelopmental disorders remain controversial. We assessed the associations between micronutrients and three main neurodevelopmental disorders, that is, autism spectrum disorder (18,381 cases), attention-deficit/hyperactivity disorder (38,691 cases), and Tourette's syndrome (4,819 cases), using two-sample Mendelian randomization analyses. In addition, we estimated the mediation role of brain imaging-derived phenotypes (n = 33,224) in these associations. Each 1 SD (0.08 mmol/L) increase in serum magnesium concentration was associated with a 16% reduced risk of autism spectrum disorder (odds ratio 0.84, 95% confidence interval 0.72-0.98). Each 1 SD (65 μmol/L) increase in blood erythrocyte zinc concentration was associated with an 8% reduced risk of attention-deficit/hyperactivity disorder (0.92, 0.86-0.98). Each 1 SD (173 pmol/L) increase in serum vitamin B12 concentration was associated with a 19% reduced risk of Tourette's syndrome (0.81, 0.68-0.97). These effects were partly mediated by alterations in multiple brain imaging-derived phenotypes, with mediated proportions ranging from 5.84% to 32.66%. Our results suggested that interventions targeting micronutrient deficiencies could be a practical and effective strategy for preventing neurodevelopmental disorders, especially in populations at high risk of malnutrition.Lay abstractIncreasing evidence highlights the critical role of micronutrients in neurodevelopment. However, the causal relationship between micronutrients and neurodevelopmental disorders remains unclear. Using genetic variants associated with micronutrient levels and neurodevelopmental disorders, our study revealed the protective effects of magnesium on autism spectrum disorders, zinc on attention-deficit/hyperactivity disorder, and vitamin B12 on Tourette's syndrome. These protective effects were partially mediated through alterations in brain structure, function, and connectivity. Our findings emphasize the importance of adequate micronutrient intake for healthy neurodevelopment and may support the development of intervention strategies aimed at preventing neurodevelopmental disorders by addressing micronutrient deficiencies.

Identifying Targets and Drugs for Rheumatoid Arthritis Stratified Therapy Using Mendelian Randomization and a Pretraining Model

The prevalence of rheumatoid arthritis (RA) subtypes, including seropositive and seronegative, is influenced by lifestyle factors and exhibits high heterogeneity, resulting in reduced drug efficacy. This study aims to identify cytokines mediating the effects of different lifestyles on RA subtypes and to discover new drugs for personalized treatment. Mendelian randomization revealed that three cytokines (MIP1b, SCGFb, and TRAIL) partially mediated the effects of different lifestyles on RA overall or its subtypes. The pretrained model, i.e., DrugBAN, predicted the probability of 723,000 small molecule drugs binding to these three targets. In molecules with high binding rates, we calculated the structural similarity between known drugs for RA and other drugs to screen for new drugs, followed by molecular docking and molecular dynamics simulations for validation. The results indicate that these targets had promising binding affinity with known drugs and other drugs with high similarity. Our findings may guide therapeutic approaches for heterogeneous RA patients with specific lifestyle habits.

Causal relationships between plasma proteins and Alzheimer's disease using bidirectional Mendelian randomization

BackgroundAlzheimer's disease (AD) is influenced by a complex interplay of genetic, immune, and metabolic factors. Identifying plasma proteins causally linked to AD could help clarify these pathways and uncover potential therapeutic targets.ObjectiveThis study aims to investigate the causal relationships between AD and plasma proteins.MethodsWe conducted a two-stage, two-sample Mendelian randomization (MR) analysis to explore the causal relationships between plasma protein levels and AD risk. In both stages, we used non-overlapping genome-wide association study datasets for exposures (plasma protein levels) and outcome (AD) to ensure robust and independent analyses. We examined both forward (from plasma proteins to AD risk) and reverse (from AD to plasma protein expression) causal effects to elucidate potential bidirectional relationships.ResultsOur MR analysis identified 25 plasma proteins with causal associations to AD, with many implicated in immune and lipid metabolic pathways. These findings reinforce the roles of inflammation and lipid metabolism in AD pathogenesis and offer novel insights into specific proteins that may serve as biomarkers or therapeutic targets.ConclusionsThis study provides further support for the relationship between immune and lipid metabolic dysregulation and AD, advancing our understanding of the molecular mechanisms underlying disease progression and highlighting key proteins for future research and therapeutic development.

Exploring the causal relationship between immune factors and chondrosarcoma: a Mendelian randomization study

BACKGROUND

Previous studies have investigated the potential role of immune factors in chondrosarcoma (CHS). However, the causal relationship is unknown.

METHODS

A two-sample Mendelian randomization (MR) was used to explore potential correlations between 731 immunocyte phenotypes, 91 inflammatory proteins, and CHS. The data were derived from published summary statistics of genome-wide association studies. Inverse-variance weighted was employed as the primary method. Furthermore, a range of analytical methods, including MR-Egger, weighted mode, and weighted median was used to enhance the robustness of the results. A two-step MR was used to assess the mediating effects of inflammatory proteins. Subsequently, sensitivity and MR Steiger directionality tests were performed.

RESULTS

MR analyses showed that 12 immunocyte phenotypes were positively correlated with CHS (P < 0.05, OR > 1), and 11 immunocyte phenotypes were negatively correlated with CHS (P < 0.05, OR < 1). Five inflammatory proteins were positively associated with CHS (P < 0.05, OR > 1). No heterogeneous or horizontal pleiotropy was found. The MR Steiger analysis found no statistically significant evidence of reverse causation. Mediation analysis did not identify any potential mediating effects.

CONCLUSION

Our study underscores the pivotal role of immune factors in CHS and offers insights that can inform future research.

Is type 2 diabetes a link between lung function and metabolic dysfunction-associated steatotic liver disease? Insights from population studies and Mendelian randomization

AIM

This study aimed to investigate the relationship between lung function and metabolic dysfunction-associated steatotic liver disease (MASLD), and the potential mediating role of type 2 diabetes.

METHODS

Data from the 2007 to 2012 National Health and Nutrition Examination Survey were used. Logistic regression analysis was employed to assess the association between lung function parameters [forced vital capacity (FVC), forced expiratory volume in 1 s (FEV 1 ), FEV 1 /FVC] and MASLD prevalence while exploring type 2 diabetes mediation. Further analyses included linkage disequilibrium score regression, Mendelian randomization, and meta-analysis to examine the causal relationship between lung function and MASLD, considering type 2 diabetes mediation.

RESULTS

The results showed that higher FVC and FEV 1 levels were associated with decreased MASLD risk, with type 2 diabetes partially mediating this relationship. Genetic analyses supported a causal link between lung function and MASLD, with type 2 diabetes acting as an intermediary. However, no significant association was found between FEV 1 /FVC and MASLD.

CONCLUSION

The study identified a causal relationship between lung function and MASLD, with type 2 diabetes playing a partial mediating role.

A Mendelian randomization study on the causal association of circulating cytokines with diabetic nephropathy

BACKGROUND

Circulating cytokines were reported to be related to diabetic nephropathy (DN) in observational studies. However, the causal relationship between them remains unknown. This study aimed to investigate the causal relationship between DN and circulating cytokines with genetic data in the frame of Mendelian Randomization (MR).

METHODS

We performed a two-sample MR analysis to investigate the causal relationship in individuals of European ancestry, utilizing publicly available genome-wide association study (GWAS) statistics. We selected eligible instrumental SNPs that were significantly related to the circulating cytokines. Multiple MR analysis approaches were employed, including inverse variance weighted (IVW), Weighted Median, MR-Egger, Weighted Mode, Simple Mode, and MR pleiotropy residual sum and outlier (MR-PRESSO) methods.

RESULTS

We found evidence supporting the causal role of genetically predicted circulating levels in the increased risk of DN. Specifically, we observed associations for interferon-gamma [OR = 1.352, 95% CI: 1.089-1.678, P = 0.006], stem cell factor [OR = 1.252, 95% CI: 1.028-1.525, P = 0.025], and stromal-cell-derived factor 1 alpha [OR = 1.326, 95% CI: 1.017-1.727, P = 0.037]. Additionally, MR analysis revealed a negative causal association between macrophage inflammatory protein 1b and DN [OR = 0.921, 95% CI: 0.858-0.988, P = 0.022]. The results obtained from MR-Egger, Weighted Median, Weighted Mode, and Simple Mode methods were consistent with the Inverse Variance Weighted (IVW) estimates. Sensitivity analyses showed no evidence of horizontal pleiotropy, suggesting that the causal estimates were not biased.

CONCLUSIONS

Our findings offer promising leads for developing novel therapeutic targets for DN. By identifying the role of inflammatory cytokines in this debilitating condition through a genetic epidemiological approach, our study made contributions to a better understanding of the underlying disease mechanisms.

Revealing the mediating mechanisms between BMI and osteoarthritis: a Mendelian randomization and mediation analysis

BACKGROUND

Despite well-documented associations between Body mass index (BMI) and Osteoarthritis (OA), the specific biological pathways and mediators involved remain poorly understood. This study aims to explore mediators through which BMI influences OA risk, particularly knee osteoarthritis (KOA), using Mendelian Randomization (MR) and mediation analysis.

METHODS

We used a two-step MR approach with data from the IEU OpenGWAS and FinnGen version 7 databases. BMI (N = 322,154) was the primary exposure, with knee disorders (KD), total bone mineral density (TBMD), metabolic disorders (MD), and anxiety disorders (AD) as potential mediators. Outcomes included KOA (N = 22,347), hip OA (HOA) (N = 11,989), and all OA (AllOA) (N = 50,508). Univariate MR evaluated causal relationships, followed by multivariate MR to quantify mediation effects. Multiple sensitivity analyses were conducted to validate robustness, while horizontal pleiotropy and heterogeneity were assessed using MR-Egger intercept and Cochran's Q statistic.

RESULTS

BMI significantly increased the risk of KOA (odds ratio [OR]: 2.00, 95% confidence interval [CI]: 1.56-2.56), HOA (OR: 2.05, 95% CI: 1.40-2.98), and AllOA (OR: 1.66, 95% CI: 1.41-1.95). KD and TBMD significantly mediated the effect on KOA, with mediation proportions of 20.89% and 3.59%, respectively. MD and AD showed no significant effects. Sensitivity analyses supported the robustness of these findings. Horizontal pleiotropy and heterogeneity tests indicated minimal evidence of bias, supporting the reliability of our results.

CONCLUSIONS

BMI increases OA risk, with KD and TBMD partially mediating the effect, particularly for KOA. The direct impact of BMI remains predominant, emphasizing the importance of weight reduction, joint protection, and physical activity as preventive measures.

Low-carbohydrate diet macronutrient quality and depression symptoms among US adults

BACKGROUND

The association between the quality of low-carbohydrate diets (LCDs) and depression symptoms remains underexplored. This study investigates the effects of LCDs on depression symptoms, with a specific focus on distinguishing the quality and quantity of macronutrients.

METHODS

In this cross-sectional study, 28,791 participants aged ≥20 were involved. Three LCD scores were constructed based the quality and quantity of macronutrients: overall LCDs (OLCDs), healthy LCDs (HLCDs: characterized by reduced intake of low-quality carbohydrates [e.g., refined sugars], higher plant-based proteins, and unsaturated fats), and unhealthy LCDs (ULCDs: characterized by reduced intake of high-quality carbohydrates [e.g., whole grains], higher animal proteins, and saturated fats). The associations between LCD patterns and depression symptoms were evaluated using multivariable logistic regression. A restricted cubic spline (RCS) regression model was used to estimate the dose-response relationship.

RESULTS

Comparing extreme quartiles of HLCDs, the adjusted odds ratio (OR) (95 % CI) for depression was 0.70 (0.57, 0.86) (P-trend <0.001). No statistical significance was observed in ULCDs and depression symptoms. Non-linear relationships were identified for OLCDs (P-non-linear = 0.017), HLCDs (P-non-linear <0.001), with depression symptoms.

CONCLUSION

Macronutrient quality modifies LCD-depression associations, with healthier patterns showing inverse correlations. Our finding indicates inverse association between HLCDs and depression risk. Further longitudinal or interventional studies are required to validate these findings and explore mechanistic pathways.

Complex interplay between type 2 diabetes mellitus and pancreatic cancer: insights from observational and mendelian randomization analyses

BACKGROUND

To investigate the causal relationship between type 2 diabetes mellitus (T2DM), pancreatic cancer (PC) risk and identify the mediating effects of various risk factors on that relationship.

METHODS

581 PC patients and 582 healthy controls who visited our center from January 2013 to December 2023 were included in this retrospective study. Multivariable logistic regression was performed to evaluate the association between T2DM and PC through odds ratios (ORs) and 95% confidence intervals (CIs). Mendelian randomization (MR) studies were then conducted to explore the causal relationship between T2DM and PC, and causal mediation analysis (CMA) to examine the mediating role of common risk factors.

RESULTS

After adjusting for confounding factors, retrospective analysis revealed significant association between new-onset diabetes mellitus (NODM) and PC risk, with insulin treatment also linked to increased PC development. The standard inverse-variance weighted (IVW) method indicated that genetic susceptibility to T2DM was associated with an increased risk of developing PC (OR = 1.11; 95% CI = 1.034-1.193). Furthermore, MR showed T2DM, insulin treatment, FGF-4, and sulfhydryl oxidase 2 may be independently associated with the prevalence of PC. Specially, CMA demonstrated that insulin treatment, FGF4, and sulfhydryl oxidase 2 mediate the pathway from T2DM to PC, contributing 56.8%, 55.8%, and 5.9% of the total effect, respectively.

CONCLUSION

This study supports the association between T2DM, specifically NODM, and increased PC risk, with insulin therapy, FGF4, and sulfhydryl oxidase 2 mediating this pathway. Further research is required to elucidate the mechanisms underlying these mediating effects.

CLINICAL TRIAL NUMBER

not applicable.

Assessing the influence of plasma metabolites on chronic skin ulcer risk: a two-sample Mendelian randomization study

Chronic skin ulcers, although rare, pose severe and debilitating challenges. The identification of causal metabolite biomarkers presents an opportunity to refine effective risk assessment strategies for this condition. In this study, we conducted a comprehensive Two-Sample Mendelian Randomization (TSMR) investigation to delineate the potential causal effects of plasma metabolites on chronic skin ulcer risk. Exposure data comprised 14,296 participants with 913 metabolites from INTERVAL/EPIC-Norfolk, and 8,299 participants with 1,091 metabolites and 309 ratios from the Canadian Longitudinal Study on Aging (CLSA). Outcome data came from the finngen_R9_L12_CHRONICULCEROFSKIN (1,840 cases, 353,088 controls) and UK Biobank Chronic ulcer of skin (495 cases, 455,853 controls) cohorts. Leveraging the inverse-variance weighted (IVW) method, alongside MR-Egger and MR-PRESSO sensitivity analyses, we evaluated metabolite associations with chronic skin ulcer risk. Further assessment involved a phenome-wide MR (Phe-MR) analysis to explore potential repercussions of targeting identified metabolites for intervention. Our study identified 12 distinct metabolites significantly associated with chronic skin ulcers, demonstrating consistent and replicable results. Notably, X-19,141 exhibited the highest reproducibility. These findings highlight novel plasma metabolites relevant to chronic skin ulcers, offering theoretical underpinnings for mechanistic research and clinical strategies in prevention and treatment.

Elucidating the critical role of gut microbiota in the pathogenesis of bacterial pneumonia: insights from a Mendelian randomization analysis mediated by immune cell

BACKGROUND

The gut microbiota (GM) is recognized as a critical factor in sustaining overall health and regulating the immune system. However, the precise function of GM in the pathogenesis of bacterial pneumonia (BP), as well as the potential involvement of immune cells in these mechanisms, remains inadequately understood. Given that BP represents a substantial public health issue, elucidating the protective role of the gut microbiota against this condition is of considerable significance.

METHODS

We employed a bidirectional two-sample univariate Mendelian randomization (UVMR) approach to investigate the potential causal relationship between GM and BP. Furthermore, we integrated UVMR with multivariate Mendelian randomization (MVMR) analysis to assess the mediating role of immune cells in the pathway linking GM to BP risk. We additionally performed a reverse analysis to exclude GM that could exhibit a reverse causal relationship with BP.

RESULTS

Mendelian randomization (MR) analysis identified 18 GM significantly associated with BP, with 8 of these bacterial taxa linked to a reduced risk and 10 associated with an increased risk. Additionally, 50 immune cell traits exhibited suggestive associations with BP, with 27 immune cells potentially conferring protection and 23 immune cells potentially augmenting risk. Importantly, mediation MR analysis revealed that the protective effect of Clostridia on BP was predominantly mediated by the proportion of HLA DR + Natural Killer cells within CD3- lymphocytes (HLA DR + Natural Killer %CD3- lymphocytes) (Total effect IVW: OR = 0.724, 95% CI [0.552, 0.950], P = 0.020). The evaluation of the mediation effect revealed an effect size of -0.025 (95% CI [-0.061, -0.000]), with a mediation effect ratio of 7.143%.

CONCLUSION

The study identified specific components of the GM that confer a protective effect against BP. It revealed that the subsets of HLA DR + Natural Killer %CD3- lymphocytes are modulated by Clostridia, thereby enhancing the host's immune defense against BP.

Exploring the silent connection: unveiling the intricate relationship between gastroesophageal reflux disease and sleep apnea syndrome

BACKGROUND

Gastroesophageal reflux disease (GERD) and Sleep Apnea Syndrome (SAS) are two prevalent medical conditions that significantly affect health and quality of life. GERD involves stomach content reflux into the esophagus, while SAS causes recurrent upper airway obstruction during sleep. Despite recent studies hinting at a link, the precise relationship and causality between GERD and SAS remain unclear. Our research uses bidirectional Mendelian randomization to explore this intricate relationship. Additionally, given SAS's high prevalence in cardiovascular patients (40-80%, as highlighted by the American Heart Association), we also investigated its potential association with various cardiovascular diseases to gain new insights into prevention and treatment.

METHODS

This study employed genetic data from large-scale genome-wide association studies (GWAS) on GERD (129,080 cases, 473,524 controls) and SAS (25,008 cases, 391,473 controls) for two-sample Mendelian randomization (MR) analysis to estimate the causal effects of GERD on the risk of SAS. All SNPs were selected using a strict clump window (r2 = 0.001 and kb = 10,000). We initially applied the inverse variance weighted (IVW) method and measured horizontal pleiotropy using MR-Egger, weighted median, and weighted mode methods. I2 index and Cochran Q statistics were used for sensitivity analysis. Funnel plot symmetry of IVW MR estimates versus 1/standard error (1/SEIV) was examined to exclude SNPs potentially causing heterogeneity. Additionally, to exclude reverse causality, bidirectional MR was employed to investigate whether genetic susceptibility to SAS causally influenced the risk of GERD.

RESULTS

GERD was associated with an elevated risk of SAS, demonstrating an odds ratio (OR) of 1.750 (95% CI 1.590-1.930; P < 0.001). Conversely, there was no compelling evidence to indicate a causal link between SAS and the risk of developing GERD, with an OR of 1.000 (95% CI 0.989-1.011; P = 0.964). In addition to the primary findings, our study also revealed significant risks associated with SAS for several cardiovascular conditions, including coronary heart disease, atrial fibrillation, coronary artery disease, heart failure, intracerebral hemorrhage, and ischemic stroke.

CONCLUSION

We discovered compelling evidence indicating an elevated risk of SAS in individuals with GERD, but no significant evidence supporting an increased risk of GERD in those with SAS. Future investigations into SAS risk should take into account the potential therapeutic targeting of GERD. PPI and histamine antagonists can effectively reduce reflux and airway secretions, preventing airway damage and collapse. Furthermore, it is necessary to investigate the underlying mechanisms by which GERD affects SAS. For example, the inflammatory stimulation caused by gastric acid and pepsin in refluxed fluid, as well as the increased tension of bronchial smooth muscle caused by vagus nerve reflex. Thus, early preventive measures can be implemented for potential complications related to SAS.

COVID-19 infection and longevity: an observational and mendelian randomization study

BACKGROUND

Studies have indicated that COVID-19 infection may accelerate the aging process in organisms. However, it remains unknown whether contracting COVID-19 affects life expectancy. Furthermore, the underlying biological mechanisms behind these findings are still unclear.

METHODS

We conducted a prospective cohort study on 56,504 participants of European ancestry from the UK Biobank who reported the time and number of COVID-19 infection between January 2020 and September 2023. The parental average longevity was used as a proxy for their own longevity. Linear regression was used to assess the relationship between COVID-19 infection and longevity. Furthermore, we investigated the shared genetic basis between COVID-19 and longevity using large-scale genome-wide association studies (GWAS) for COVID-19 (122,616 cases and 2,475,240 controls) and longevity (3,484 cases and 25,483 controls). Mendelian randomization (MR) and mediation analysis were utilized to assess causal relationships and potential mediators between COVID-19 susceptibility and longevity. Shared genetic loci between the two phenotypes were identified using conjunctional false discovery rate (conjFDR) statistical frameworks.

RESULTS

After controlling for relevant covariates, COVID-19 infection might not be significantly correlated with longevity. In all MR methods, generalized summary-data-based Mendelian randomization (GSMR) analysis revealed a significant decrease in longevity due to severe COVID-19 infection (OR = 0.91, 95%CI: 0.84-0.98, P = 0.015). Mediation analysis identified stroke and myocardial infarction as potential mediators between COVID-19 susceptibility and reduced longevity. At conjFDR < 0.05, we identified rs62062323 (KANSL1) and rs9530111 (PIBF1) as shared loci between COVID-19 and longevity.

CONCLUSION

Together, our findings provided preliminary evidence for the shared genetic basics between COVID-19 and aging. This discovery may have implications for personalized medicine and preventive strategies, helping identify individuals who may be more vulnerable to severe outcomes from COVID-19 due to their genetic makeup.

Systematic Evaluation of the Impact of a Wide Range of Dietary Habits on Myocardial Infarction: A Two-Sample Mendelian Randomization Analysis

BACKGROUND

Myocardial infarction is a cardiovascular disease that significantly contributes to global morbidity and disability. Given the significant role of diet in the pathogenesis and prevention of cardiovascular diseases, this study rigorously investigates the causal relationship between dietary habits and myocardial infarction.

METHODS AND RESULTS

This study used large-scale genome-wide association studies with pooled UK Biobank data to explore associations between 9 dietary categories (83 types) and myocardial infarction. A 2-sample Mendelian randomization approach was applied to assess these associations, while multivariate Mendelian randomization and mediation analyses investigated the role of lipids in mediating the effects of diet on myocardial infarction. Univariate Mendelian analyses revealed genetic associations among 9 categories of dietary habits (83 types) and myocardial infarction. Notably, robust evidence indicates the "tablespoons of cooked vegetables per day" as the most significant risk factor for myocardial infarction development. "Coffee consumption(cups per day)" and "frequency of adding salt to food" were also identified as supplementary risk factors. In contrast, "overall alcohol intake" showed a protective effect, potentially by increasing high-density lipoprotein cholesterol (4.48% mediation) and reducing triglycerides (6.24% mediation). Cereal category, particularly "cereal consumption (bowls per week)" was associated with reduced myocardial infarction risk, contributing by raising high-density lipoprotein cholesterol (3.69% mediation) and lowering total cholesterol (8.33% mediation). Additionally, "overall cheese consumption" was also protective against myocardial infarction.

CONCLUSIONS

Our findings elucidate the influence of dietary habits on myocardial infarction, showing underlying genetic mechanisms and emphasizing the regulatory role of lipids as an intermediate.

Association between stroke and fracture and the mediating role of depression: a cross-sectional study from NHANES 2017 to 2020

Background

Stroke is a significant health threat, and its complex interplay with fractures warrants further investigation. Depression, a critical psychological mediator in various health conditions, may also play a role. This study aims to clarify the intricate relationships among stroke, depressive symptoms, and fracture risk, potentially informing more holistic clinical strategies.

Methods

Utilizing the most recent data from the National Health and Nutrition Examination Survey (NHANES, 2017 to 2020), this study encompassed 4,979 valid samples. T-test and chi square test are conducted to compare the differences between fracture and non fracture subgroups. Subsequently, regression models were applied to assess the mediating impact of depression, with Sobel's test and the bootstrap method deployed to substantiate the mediation pathways.

Results

In this study, we conducted subgroup and regression analyses to investigate factors influencing fractures in stroke patients using NHANES data. Subgroup analysis revealed significant associations with gender, race, osteoporosis, and depression. Female stroke patients had a higher fracture rate (73.86% vs. 47.78%, p < 0.001), and those with post-stroke depression (29.67% vs. 13.16%, p < 0.001) or osteoporosis (33.33% vs. 15.81%, p < 0.05) were at increased risk of fractures. Logistic regression models showed a positive association between stroke and fractures in the unadjusted (OR = 1.862, 95% CI: 1.348-2.573, p < 0.001) and adjusted I models (OR = 1.789, 95% CI: 1.240-2.581, p < 0.01), but not in the adjusted II model. Depression was significantly correlated with fractures in all models (unadjusted OR = 2.785, 95% CI: 1.271-6.101, p < 0.05; Model 1 OR = 3.737, 95% CI: 1.470-9.498, p < 0.01; Model 2 OR = 3.068, 95% CI: 1.026-9.175, p < 0.05). Mediation analysis using Sobel and bootstrap tests indicated that depression mediates 7.657% of the relationship between stroke and fractures (Z = 2.31, p < 0.05), with significant indirect (Z = 2.80, p < 0.01), direct (Z = 3.61, p < 0.001), and total effects (Z = 3.92, p < 0.01). The direct effect of stroke on fracture was 0.079 (95% CI: 0.036-0.121), the total effect was 0.085 (95% CI: 0.043-0.128), and the indirect effect mediated by depressive symptoms was 0.007 (95% CI: 0.002-0.011). These results suggest that depressive symptoms following stroke may contribute to an increased risk of fractures.

Conclusion

Depressive symptoms serve as a critical mediator in the link between stroke and fracture risk. Consequently, our study concludes that holistic prevention strategies for fractures in stroke patients must incorporate a focus on mental health to effectively address this complex clinical challenge.

Altered food liking in depression is driven by macronutrient composition

Major depressive disorder (MDD) is characterized by changes in appetite and body weight as well as blunted reward sensitivity (‘anhedonia’). However, it is not well understood which mechanisms are driving changes in reward sensitivity, specifically regarding food. Here, we used a sample of 117 participants (54 patients with MDD and 63 healthy control participants [HCPs]) who completed a food cue reactivity task with ratings of wanting and liking for 60 food and 20 non-food items. To evaluate which components of the food may contribute to altered ratings in depression, we tested for associations with macronutrients of the depicted items. In line with previous studies, we found reduced ratings of food wanting (p = .003) but not liking (p = .23) in patients with MDD compared to matched HCPs. Adding macronutrient composition to the models of wanting and liking substantially improved their fit (ps < .001). Compared to carbohydrate-rich foods, patients with MDD reported lower liking and wanting ratings for high-fat and high-protein foods. Moreover, patients with MDD showed weaker correlations in their preferences for carbohydrate- versus fat- or protein-rich foods (ps < .001), pointing to potential disturbances in metabolic signaling. To conclude, our results suggest that depression-related alterations in food reward ratings are more specific to the macronutrient composition of the food than previously anticipated, hinting at disturbances in gut–brain signaling. These findings raise the intriguing question of whether interventions targeting the gut could help normalize aberrant reward signals for foods rich in fat or protein.

Multi-dimensional evidence from the UK Biobank shows the impact of diet and macronutrient intake on aging

BACKGROUND

The role of diet in aging is crucial, yet research findings on how specific diets influence human aging remain inconsistent. Understanding the relationship between dietary factors and aging could inform interventions to promote healthier aging outcomes.

METHODS

We analyzed data from the UK Biobank baseline survey and a 24-hour dietary assessment survey to investigate the association between diet and aging. The study examined 18 individual food intakes, 6 dietary patterns, 3 macronutrient intakes, and 3 dietary quality scores. High-dimensional Fixed Effects (HDFE) models were used to assess associations between dietary factors and aging measures, including telomere length, phenotypic age, and brain grey/white matter volumes. Multivariable Mendelian Randomization (MVMR) was employed to explore causal links between macronutrient consumption and aging outcomes.

RESULTS

Our results show that healthier diets are generally associated with improved aging outcomes from HDFE analyses. Plant-based food consumption correlates with increased telomere length and reduced phenotypic age, while animal-based food intake is linked to adverse aging effects. MVMR results confirm the causal benefits of carbohydrate intake, including reductions in phenotypic age (β = -0.0025; 95% CI = [-0.0047, -0.0003]; p = 0.0253) and increases in whole-brain grey matter volume (β = 0.0262; 95% CI = [0.007, 0.046]; p = 0.0087). The latter association remains significant after multiple testing correction.

CONCLUSIONS

This study underscores the significant role of diet in biological aging and provides robust evidence for the benefits of carbohydrate intake in promoting healthier aging. These findings highlight the potential of dietary interventions to improve aging-related outcomes.

Genetically Supported Causality Between Micronutrients and Sleep Behaviors: A Two-Sample Mendelian Randomization Study

BACKGROUND

Sleep behaviors, defined by the total duration of sleep and chronotype, significantly influence overall health. Compromised sleep quality, which is often manifested through reduced sleep duration and the prevalence of insomnia, has been found to be associated with micronutrient deficiencies. Nonetheless, the existence of a causal relationship between micronutrient levels and sleep behaviors remains to be established.

METHODS

A two-sample Mendelian randomization (MR) analysis, utilizing data from genome-wide association studies (GWAS), was employed to examine the associations between 15 micronutrients (copper; calcium; carotene; folate; iron; magnesium; potassium; selenium; vitamins A, B12, B6, C, D, and E; and zinc) and various sleep behaviors, including short and long sleep durations, insomnia, and chronotype. Furthermore, multivariable MR (MVMR) analysis was performed to address potential confounding due to the interrelationships among micronutrients and to discern potential causal relationships.

RESULTS

The MR analysis identified a causal association between folate levels and chronotype (odds ratio [OR] = 1.09; 95% confidence interval [CI]: 1.01-1.17; p = 0.02), indicating a tendency toward morningness. Conversely, vitamin B6 (OR = 0.91; 95% CI: 0.86-0.96; p = 1.05 × 10-3) and vitamin D (OR = 0.94; 95% CI: 0.88-1.00; p = 0.03) showed inverse associations with chronotype, indicative of a preference for eveningness. MVMR analysis confirmed the positive association between folate (OR = 1.286, 95% CI = 1.124-1.472, p < 0.001) and chronotype and a negative association with vitamin B6 (OR = 0.750, 95% CI = 0.648-0.868, p < 0.001). No causal relationships were established between micronutrient levels and either sleep duration or insomnia.

CONCLUSIONS

Elevated folate levels correlate with morning-type preferences ("morning birds"), while higher concentrations of vitamin B6 are associated with evening-type preferences ("evening owls").

Causal associations between iron levels in subcortical brain regions and psychiatric disorders: a Mendelian randomization study

Despite observational studies linking brain iron levels to psychiatric disorders, the exact causal relationship remains poorly understood. This study aims to examine the relationship between iron levels in specific subcortical brain regions and the risk of psychiatric disorders. Utilizing two-sample Mendelian randomization (MR) analysis, this study investigates the causal associations between iron level changes in 16 subcortical nuclei and eight major psychiatric disorders, including schizophrenia (SCZ), major depressive disorder (MDD), autism spectrum disorders (ASD), attention-deficit/hyperactivity disorder, bipolar disorder, anxiety disorders, obsessive-compulsive disorder, and insomnia. The genetic instrumental variables linked to iron levels and psychiatric disorders were derived from the genome-wide association studies data of the UK Biobank Brain Imaging and Psychiatric Genomics Consortium. Bidirectional causal estimation was primarily obtained using the inverse variance weighting (IVW) method. Iron levels in the left substantia nigra showed a negative association with the risk of MDD (ORIVW = 0.94, 95% CI = 0.91-0.97, p < 0.001) and trends with risk of SCZ (ORIVW = 0.90, 95% CI = 0.82-0.98, p = 0.020). Conversely, iron levels in the left putamen were positively associated with the risk of ASD (ORIVW = 1.11, 95% CI = 1.04-1.19, p = 0.002). Additionally, several bidirectional trends were observed between subcortical iron levels and the risk for psychiatric disorders. Lower iron levels in the left substantia nigra may increase the risk of MDD, and potentially increase the risk of SCZ, indicating a potential shared pathogenic mechanism. Higher iron levels in the left putamen may lead to the development of ASD. The observed bidirectional trends between subcortical iron levels and psychiatric disorders, indicate the importance of the underlying biomechanical interactions between brain iron regulation and these disorders.

Exploring the causal relationships between cholelithiasis, cholecystitis, cholecystectomy, and gastroesophageal reflux disease: a bidirectional two-sample Mendelian randomization study

BACKGROUND

Biliary disorders and gastroesophageal reflux disease (GERD) frequently coexist. However, precise linkages between these conditions remain to be clarified.

METHODS

Univariable Mendelian randomization (MR), Bayesian weighted MR (BWMR) along with multivariable MR approaches were conducted using genetic instruments to evaluate the causality involving biliary disorders and GERD. Furthermore, an investigation was conducted on the potential mediating roles of biliary disorders (or GERD), on the linkage involving BMI and GERD (or biliary disorders).

RESULTS

Univariable MR analyses revealed significant causal effects of genetically predicted cholelithiasis [odds ratio (OR)=1.04, P =0.0001], cholecystitis (OR=1.06, P =0.0004), and cholecystectomy (OR=2.56, P =1.05×10 -6 ) on GERD. These findings were replicated in the FinnGen cohort and were also confirmed by BWMR and multivariable MR analyses. Additionally, mediation analyses demonstrated that cholelithiasis and cholecystitis acted as partial mediators, linking BMI causally to GERD. Conversely, GERD exhibited causal effect on cholelithiasis (OR=1.52, P =9.17×10 -30 ) and cholecystitis (OR=1.90, P =3.32×10 -28 ), which remained significant after BWMR and multivariable MR analyses. Mediation analyses further revealed significant mediating effect of GERD on how BMI influenced cholelithiasis/cholecystitis.

CONCLUSION

Our study elucidates the bidirectional causal linkages involving cholelithiasis, cholecystitis, cholecystectomy, and GERD. These results highlight the significance of GERD risk assessment in individuals suffering from biliary diseases and vice versa.

Sodium-glucose cotransporter protein 2 inhibition, plasma proteins, and ischemic stroke: A mediation Mendelian randomization and colocalization study

PURPOSE

To determine the effect of the sodium-glucose cotransporter protein 2 (SGLT2) inhibition on ischemic stroke (IS) and investigate the circulating proteins that mediate the effects of SGLT2 inhibition on IS.

METHODS

The effects of SGLT2 inhibition on IS were evaluated using two-sample Mendelian randomization (MR) analyses. The 4,907 circulating proteins from the plasma proteome were assessed to identify potential mediators. Sensitivity, colocalization, and external validation analyses were conducted to validate critical findings. MR analyses were also used to evaluate the associations of SGLT2 inhibition with magnetic resonance imaging (MRI)-based biomarkers and functional prognoses post-IS.

RESULTS

SGLT2 inhibition was significantly associated with decreased risks of IS (odds ratio (OR): 0.39, 95 % confidence interval (CI): 0.25-0.61, p = 3.53 × 10-5) and cardioembolic stroke (OR: 0.16, 95 % CI: 0.07-0.37, p = 1.82 × 10-5); the effect of SGLT2 inhibition on IS was indirectly mediated through pathways involving tryptophanyl-transfer RNA synthetase (WARS) (β:0.08, 95 % CI:0.15 - -0.01, p = 0.034) and matrix metalloproteinase 12 (MMP12) (β:0.06, 95 % CI:0.12 - -0.01, p = 0.016), with mediation proportions of 8.2 % and 6.8 %, respectively. The external validation confirmed the WARS mediating effect. In addition, the sensitivity and colocalization analyses and MR analyses of MRI biomarker-based and functional prognostic outcomes supported these results.

CONCLUSION

In this study, we demonstrated from a genetic perspective that SGLT2 inhibitors prevent the development of IS and improve functional prognostic outcomes and brain microstructural integrity. WARS and MMP12 may act as potential mediators, presenting a novel approach for IS intervention.

Dietary Factors Associated with Depressive Symptoms in Midlife Women 40-50 Years of Age Living in the United States

Purpose

Women in the decade before menopause are at risk for depression. This study describes dietary factors associated with depression risk in late premenopausal women that could be modifiable with targeted interventions.

Methods

Descriptive cross-sectional study comparing a community-based sample of 342 healthy premenopausal women categorized as low-risk and high-risk for depression in a secondary analysis of dietary variables. Depression risk was estimated with the Center for Epidemiological Studies-Depression (CES-D) scale. Dietary variables were based on three random 24-hour diet recalls during a 1-week period that included an in-person visit with measures of potential covariates such as blood pressure, height, and weight for body mass index (BMI), a urine sample for follicle-stimulating hormone, demographic factors, exercise and sleep. Independent t-tests were used initially to compare groups, followed by logistic regression to adjust for covariates. Statistical significance was set at p ≤ 0.05.

Results

Depression risk (CES-D ≥ 16) was present in 30% of participants. Compared with the low-risk group, the high-risk group had significantly higher intake of polyunsaturated fat, omega-6 linoleic acid and sucrose, and lower intake of galactose, vitamin C, and omega-3 eicosapentaenoic acid. After adjusting for energy intake and significant covariates (income adequacy, education, race/ethnicity, marital status, BMI, exercise and sleep duration), only polyunsaturated fat, omega-6, and sucrose remained significant.

Conclusion

Depression prior to menopause is common and multifactorial. Findings support the importance of assessing saturated fats, omega-6 fatty acids, and sucrose. Attention to diet in addition to exercise and sleep may improve intervention outcomes for mental health in midlife women.

Exploring the shared genetic basis of major depressive disorder and frailty

BACKGROUND

Major depressive disorder (MDD) and frailty impose substantial health and economic burdens. MDD is recognized as a significant risk factor for frailty, but the genetic associations between these conditions remain unclear. This study investigates the genetic correlation, shared pleiotropic loci, causal relationships, and comorbid genes between MDD and frailty.

METHODS

The genetic correlation between MDD and frailty was assessed using linkage disequilibrium score regression (LDSC) based on data from genome-wide association studies (GWAS). A detailed analysis was performed to identify shared pleiotropic loci and causal relationships through cross-phenotype association tests and Mendelian randomization. Additionally, tissue enrichment analysis was conducted using stratified LDSC, gene-based associations with both conditions were assessed using Multimarker Analysis of Genomic Annotation (MAGMA), and pathway analysis of comorbid genes was performed using the g: GOSt tool.

RESULTS

Our findings revealed a significant positive genetic correlation between MDD and frailty (rg = 0.65, P = 1.49E-219). We identified 57 shared risk SNPs between the two conditions, including 6 novel SNPs. Mendelian randomization analyses indicated robust causal effects of MDD on frailty and vice versa. Furthermore, we observed tissue-specific heritability enrichment in 9 brain tissues. By combining MAGMA and CPASSOC analyses, we identified 10 comorbid genes associated with both MDD and frailty, primarily involved in synapse formation, modulation, plasticity, and desaturase activity.

CONCLUSION

This study provides strong evidence for a shared genetic basis between MDD and frailty. The identification of comorbid genes offers new insights into the mechanisms underlying the relationship between these conditions.

Higher caloric ratio of carbohydrate intake associated with increased risk of depression: A cross-sectional analysis of NHANES data from 2005 to 2020

INTRODUCTION

Depression remains a significant global mental health challenge. However, the relationship between the Caloric Ratio of Carbohydrate Intake (CRC) and depression remains unclear.

METHODS

This study utilizes data from the NHANES database spanning 2005-2020 and employs R programming language for data analysis. Depression was assessed using the Patient Health Questionnaire-9 (PHQ-9). CRC was calculated as total carbohydrate intake*4/total caloric intake. Multivariable logistic regression models and regression spline models were applied to further explore the relationship between CRC and Depression.

RESULTS

Data from 9254 participants were included, with 1530 individuals identified with depression. A higher CRC, exceeding 54.1 % (Quartile 4 (Q4) of the population), was associated with higher levels of depressive symptoms. Adjusted multivariable logistic regression models indicated a higher depression level (β = 0.5102, 95%CI [0.2419-0.7784], P = 0.0002), higher risk of depression (HR = 1.3380, 95 % CI [1.1331-1.5812], P = 0.0006) and higher impact of depression on life (HR = 1.5133, 95 % CI [1.1656-1.9746], P = 0.0020) at CRC-Q4 levels compared to Quartile 1 (Q1) of the population levels.

CONCLUSION

In this extensive cross-sectional study, our findings suggest that a higher CRC is significantly associated with an increased likelihood of depressive symptoms among U.S. adults.

Evidence from mendelian randomization identifies several causal relationships between primary membranous nephropathy and gut microbiota

BACKGROUND

Research has showcased a correlation between disruptions in gut microbiota and primary membranous nephropathy (pMN), giving rise to the concept of the 'gut-kidney axis'. However, the precise relationship between gut microbiota and pMN remains elusive. Hence, this study endeavors to investigate whether a causal relationship exists between gut microbiota and pMN utilizing Mendelian randomization (MR) analysis.

METHODS

The primary method employed for MR analysis is the inverse variance weighting method, supplemented by MR-Egger and the weighted median method, to infer causality. This approach was validated within the pMN cohort across two distinct populations.

RESULTS

At the species level, the abundance of Bifidobacterium bifidum and Alistipes indistinctus was negatively correlated with the risk of pMN. Conversely, pMN was positively associated with Bacilli abundance at the class level, Lachnospiraceae abundance at the family level, and Dialister abundance at the genus level. Specifically, at the species level, pMN was positively correlated with the abundance of Ruminococcus lactaris, Dialister invisus, and Coprococcus_sp_ART55_1.

CONCLUSION

These findings lay the groundwork for future research exploring the interplay between pMN and the gut microbiota, with substantial implications for the prevention and treatment of pMN and its associated complications.

Assessment of bidirectional relationships between frailty and acute respiratory distress syndrome: a bidirectional Mendelian Randomization study

BACKGROUND

While previous observational studies have suggested a link between frailty and acute respiratory distress syndrome (ARDS), the causality of this connection remains unclear. The objective of this study was to explore the potential bidirectional causal links between frailty and ARDS.

METHODS

A two-sample univariable Mendelian randomization (MR) was performed to assess the causal relationship between frailty, as defined by frailty index (FI, n = 175,226) and fried frailty score (FFS, n = 386,565), and ARDS. The genome-wide association study (GWAS) data of frailty was from the UK Biobank and the ARDS data was from the FinnGen Database. Univariable MR analyses were conducted using inverse-variance weighted (IVW), weighted median, MR-Egger regression, and robust adjusted profile score (MR. RAPS). We also performed multivariable Mendelian randomization (MVMR) analysis including smoking initiation, alcohol consumption, body mass index (BMI), and cognitive performance.

RESULTS

This bidirectional MR analysis demonstrated no causal effect of FI (OR = 0.96, 95% CI 0.14-6.88) and FFS (OR = 1.95, 95%CI 0.14-28.16) on increased susceptibility of ARDS. Also, no evidence was found for an effect of ARDS on the risk of frailty. The MVMR analysis indicated higher BMI and poorer cognitive performance were associated with increased risk of ARDS.

CONCLUSIONS

The outcomes of our analysis imply a probable absence of a direct causal relationship between frailty and susceptibility to ARDS. To reinforce and expand upon these preliminary findings, it is imperative to conduct larger-scale genome-wide association studies.

Type 1 Diabetes and Cataracts: Investigating Mediating Effects of Serum Metabolites Using Bidirectional Mendelian Randomization

PURPOSE

To investigate the causal relationship between type 1 diabetes (T1D) and cataracts and to explore the mediating role of serum metabolites.

METHODS

This study employed bidirectional Mendelian randomization (MR) using genetic variants as instrumental variables to infer causality in both directions: from T1D to cataracts and cataracts to T1D. Genetic data for T1D, its complications, and cataracts were sourced from independent genome-wide association study (GWAS) datasets. A two-step multivariable MR combined with mediation analysis was conducted to evaluate the indirect effects of serum metabolites in the causal pathway from T1D to cataracts.

RESULTS

The MR analysis demonstrated a significant causal association between T1D and an increased risk of cataracts (OR = 1.01-1.05; p < 0.05). Further analysis showed that patients with T1D complications such as coma, ketoacidosis, nephropathy, and retinopathy exhibited a significantly higher risk of developing cataracts compared to those without complications. Sensitivity analyses upheld the robustness of these findings, with no evidence of heterogeneity or pleiotropy. Additionally, 102 serum metabolites were found to exhibit statistically significant mediation effects on cataract risk, with four (13-HODE + 9-HODE, 2-naphthol sulfate, docosadienoate (22:2n6), and X-12906) showing significant mediation effects. Specifically, 13-HODE + 9-HODE had a protective effect, while the other three metabolites were linked to an increased cataract risk.

CONCLUSIONS

This study provides strong evidence of a causal link between T1D and cataracts, highlighting the mediating role of specific serum metabolites. These findings underscore the importance of early detection and management of cataracts in patients with T1D and suggest potential therapeutic targets for mitigating cataract risk. Further research should focus on replicating these findings in diverse populations and exploring the underlying metabolic pathways in greater detail.

Mitochondrial related Mendelian randomization identifies causal associations between metabolic disorders and childhood neurodevelopmental disorders

Childhood neurodevelopmental disorders (NDDs), including autism spectrum disorder (ASD), attention-deficit hyperactivity disorder, and Tourette syndrome, are a predominant cause of health-related disabilities in children and adolescents. Nevertheless, disease biomarkers are still limited. The aim of this study was to evaluate the potential, causal relationship between mitochondrial DNA copy number (mtDNA-CN), metabolic disorders, and childhood NDDs using the two-sample Mendelian randomization (MR) method. Genetic associations with mtDNA-CN, disorders of lipoprotein metabolism, and disorders of iron metabolism were selected as exposures, and genome-wide association data from ASD, attention-deficit hyperactivity disorder, and Tourette syndrome were utilized as outcomes. Results of the study suggested that a high degree of disordered lipoprotein metabolism related increases in ASD risk result from a decrease in mtDNA-CN (disordered lipoprotein metabolism-mtDNA: inverse variance weighting β: -0.03, 95% confidence interval: -0.05 to -0.02, P = 2.08 × 10-5; mtDNA-CN-ASD: inverse variance weighting odds ratio: 0.83, 95% confidence interval: 0.69-0.99, P = .034). The research findings implied that mtDNA-CN can mediate disorders of lipoprotein metabolism, potentially influencing the development of ASD. The potential impact of the results of this study for the prevention and treatment of childhood NDDs warrants validation in robust randomized clinical trials.

Causal relationship between sleep characteristics and thyroid function: A bidirectional Mendelian randomization study

BACKGROUND

Previous researches have revealed some links between thyroid function and sleep characteristics, however it remains unclear which one causes the other. The purpose of this study was to investigate the potential causal relationship between hyperthyroidism, hypothyroidism, and sleep characteristics.

METHODS

We utilized aggregated data from published genome-wide association studies (GWAS) to select genetic instruments for sleep variables. The 5 sleep-related traits (chronotype, short sleep duration, long sleep duration, daytime sleepiness, and insomnia) were associated with distinct genetic variants chosen as instrumental factors. Employing MR Egger's analysis of Mendelian randomization (MR), weighted median, weighted mode, and inverse variance weighted (IVW) methods to assess the 5 sleep traits in relation to hyperthyroidism and hypothyroidism, we subsequently conducted inverse MR analysis to examine the causal relationship between thyroid function and the 5 sleep characteristics.

RESULTS

The IVW technique did not reveal a causal association between chronotype, short sleep duration, long sleep duration, daytime sleepiness, or insomnia and the risk of abnormal thyroid function in the study investigating the influence of sleep characteristics on this risk. The outcomes of the IVW approach were consistent with the remaining 3 methods. The IVW, weighted median, MR Egger, and weighted mode methods in the reverse magnetic resonance imaging investigation did not yield evidence of a causative association between the risk of time type, long sleep duration, and insomnia and abnormal thyroid function. In contrast, the weighted median and weighted mode methods showed a possible causal relationship between hypothyroidism and short sleep duration and daytime sleepiness. Sensitivity analyses showed that the results were robust and no pleiotropy or heterogeneity was detected.

CONCLUSION

More precisely, our analysis did not uncover any indication of a reciprocal causal link between thyroid function and genetically predicted sleep characteristics.

Causal Effects of Sleep Quality on Primary Headache and the Mediation via Gut Microbiota: A Mendelian Randomization Study

BACKGROUND

Previous studies have shown that sleep quality plays an essential role in primary headaches to varying degrees. However, it is unclear precisely whether gut microbiota plays a critical role in mediating changes in sleep quality and affecting primary headaches.

METHODS

We utilized Mendelian randomization (MR) to examine the causal relationships between sleep quality and primary headaches. The data encompass eight sleep traits (staying asleep during periods of anxiety, trouble falling asleep, daytime dozing, sleep apnea syndrome, oversleeping, undersleeping, snoring, and sleeplessness). The primary statistical method employed was inverse variance weighting. Eventually, we explored whether gut microbiota mediate the relationship between sleep quality and primary headaches.

RESULTS

Our study found that a genetic predisposition to poor sleep quality increases the risk of primary headaches. Two-step MR analysis revealed that the genus Coprococcus1 mediates the causal relationship between trouble falling asleep and cluster headaches, with a mediating effect of 23.6%. These findings could inform targeted interventions and treatments for primary headaches.

CONCLUSION

This study suggests that trouble falling asleep increases the incidence of cluster headaches mediated by gut microbiota. It highlights the crucial impact of sleep quality on primary headaches.

Associations between specific dietary patterns, gut microbiome composition, and incident subthreshold depression in Chinese young adults

INTRODUCTION

The interplay between influential factors and the incidence of subthreshold depression (SD) in young adults remains poorly understood.

OBJECTIVES

This study sought to understand the dietary habits, gut microbiota composition, etc. among individuals with SD in young adults and to investigate their association with SD occurrence.

METHODS

Employing a cross-sectional approach, 178 individuals with SD, aged 18-32 years, were matched with 114 healthy counterparts. SD status was evaluated using the Zung Self-rating Depression Scale (SDS), Zung Self-rating Anxiety Scale (SAS), Beck Depression Inventory 2nd version (BDI-II), the 17-item Hamilton Rating Scales of Depression (HAMD-17), and Pittsburgh Sleep Quality Index (PSQI). Metagenomic sequencing was utilized to identify fecal microbial profiles. Dietary patterns were discerned via factor analysis of a 25-item food frequency questionnaire (FFQ). Logistic regression analysis and mediation analysis were performed to explore the potential links between gut microbiota, dietary patterns, and incident SD.

RESULTS

Data on dietary habits were available for 292 participants (mean [SD] age, 22.1 [2.9] years; 216 [73.9 %] female). Logistic regression analysis revealed that dietary patterns Ⅰ (odds ratio [OR], 0.34; 95 % CI, 0.15-0.75) and IV (OR, 0.39; 95 % CI, 0.17-0.86 and OR, 0.39; 95 % CI, 0.18-0.84) were associated with reduced risk of SD. Distinct microbial profiles were observed in young adults with SD, marked by increased microbial diversity and taxonomic alterations. Moreover, mediation analysis suggested Veillonella atypica as a potential mediator linking SDS or BDI-II scores with a healthy dietary pattern rich in bean products, coarse grains, nuts, fruits, mushrooms, and potatoes (β = 0.25, 95 % CI: 0.02-0.78 and β = 0.18, 95 % CI: 0.01-0.54).

CONCLUSIONS

Our findings highlight the complex interplay between dietary patterns, gut microbiota, and the risk of developing SD in young adults, underscoring the potential for dietary interventions and microbiome modulation in mental health promotion.

Association of lipids and lipid-lowering drugs with peripheral arterial disease: A Mendelian randomization study

BACKGROUND

It remains unclear whether lipid profiles and lipid-lowering medications are causally related to peripheral arterial disease (PAD).

OBJECTIVE

Explain whether there is a causal relationship between lipid status and lipid-lowering drugs and PAD.

METHODS

In this two-sample Mendelian randomization (MR) analysis, we assessed the causal relationship between lipid traits, including high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), triglycerides (TGs), total cholesterol (TC), and LDL-associated genetic variants (HMGCR, NPC1L1, PCSK9, APOB), and the risk of PAD using genetic variants associated with these lipid markers. The study analyzed data from 1,654,960 individuals derived from the Global Lipid Genetics Consortium and the UK Biobank, ensuring a robust and comprehensive genetic insight into the effects of lipid dysfunction on PAD.

RESULTS

We found genetically predicted associations between HDL-C (OR: 0.83, 95% CI: 0.83-0.77), LDL-C (OR: 1.29, 95% CI: 1.12-1.50), TC (OR: 1.14, 95% CI: 1.01- 1.29), TG (OR: 1.16, 95% CI: 1.04-1.24), APOB (OR: 1.31, 95% CI: 1.16-1.48), and APOA1 (OR: 0.84, 95% CI: 0.77-0.97), and the risk of PAD. In addition, inhibition of PCSK9 was associated with a reduced risk of PAD (OR: 0.68, 95% CI: 0.57-0.79, P<0.001), while no association between the other three gene proxies of LDL inhibition including HMGCR (OR: 1.21, 95% CI: 0.87-1.69, P=0.250), NPC1L1 (OR: 0.77, 95% CI: 0.44-1.33, P=0.344), and APOB (OR: 1.01, 95% CI: 0.87-1.26, P=0.890), and the risk of PAD were found.

CONCLUSIONS

Based on genetic evidence, dyslipidemia is an important risk factor for PAD. Proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors may be an effective strategy for the treatment of PAD.

Association between biological ageing and periodontitis: Evidence from a cross-sectional survey and multi-omics Mendelian randomization analysis

AIM

To investigate the relationship and potential causality between biological ageing and periodontitis.

MATERIALS AND METHODS

We obtained the National Health and Nutrition Examination Survey (NHANES) and genome-wide association study (GWAS) summary statistics as well as single-cell sequencing data. Multivariate regression analysis based on cross-sectional data, Mendelian randomization (MR) and multi-omics integration analysis were employed to explore the causal association and potential molecular mechanisms between biological ageing and periodontitis. Additionally, two-step MR mediation analysis explored the risk factors in biological ageing-mediated periodontitis.

RESULTS

We analysed data from 3189 participants in the NHANES data and found that higher biological age was associated with increased risk of periodontitis. MR analyses revealed causal associations between biological age measures and periodontitis risk. Frailty (odds ratio [OR] = 2.08, 95% confidence interval [CI]: 1.04-4.18, p = .039) and GrimAge acceleration (OR = 1.16, 95% CI: 1.01-1.32, p = .033) were causally associated with periodontitis risk, and these results were validated in a large-scale meta-periodontitis GWAS dataset. Additionally, the risk effects of body mass index, waist circumference and lifetime smoking on periodontitis were partially mediated by frailty and GrimAge acceleration.

CONCLUSIONS

Evidence from cross-sectional survey and MR analysis suggests that biological ageing increases the risk of periodontitis. Additionally, improving the associated risk factors can help prevent both ageing and periodontitis.

Unraveling the causal relationships between depression and brain structural imaging phenotypes: A bidirectional Mendelian Randomization study

BACKGROUND

Previous studies have revealed structural brain abnormalities in individuals with depression, but the causal relationship between depression and brain structure remains unclear.

METHODS

A genetic correlation analysis was conducted using summary statistics from the largest genome-wide association studies for depression (N = 674,452) and 1,265 brain structural imaging-derived phenotypes (IDPs, N = 33,224). Subsequently, a bidirectional two-sample Mendelian Randomization (MR) approach was employed to explore the causal relationships between depression and the IDPs that showed genetic correlations with depression. The main MR results were obtained using the inverse variance weighted (IVW) method, and other MR methods were further employed to ensure the reliability of the findings.

RESULTS

Ninety structural IDPs were identified as being genetically correlated with depression and were included in the MR analyses. The IVW MR results indicated that reductions in the volume of several brain regions, including the bilateral subcallosal cortex, right medial orbitofrontal cortex, and right middle-posterior part of the cingulate cortex, were causally linked to an increased risk of depression. Additionally, decreases in surface area of the right middle temporal visual area, right middle temporal cortex, right inferior temporal cortex, and right middle-posterior part of the cingulate cortex were causally associated with a heightened risk of depression. Validation and sensitivity analyses supported the robustness of these findings. However, no evidence was found for a causal effect of depression on structural IDPs.

CONCLUSIONS

Our findings reveal the causal influence of specific brain structures on depression, providing evidence to consider brain structural changes in the etiology and treatment of depression.

Effect of Relative Protein Intake on Hypertension and Mediating Role of Physical Fitness and Circulating Fatty Acids: A Mendelian Randomization Study

OBJECTIVE

To investigate the causal effect of protein intake on hypertension and the related mediating pathways.

PATIENTS AND METHODS

Using genome-wide association study summary statistics of European ancestry, we applied univariable and multivariable Mendelian randomization to estimate the bidirectional associations of relative protein intake and related metabolomic signatures with hypertension (FinnGen: Ncase=42,857/Ncontrol=162,837; UK Biobank: Ncase=77,723/Ncontrol=330,366) and blood pressure (International Consortium of Blood Pressure: N=757,601) and two-step Mendelian randomization to assess the mediating roles of 40 cardiometabolic factors therein. Mendelian randomization estimates of hypertension from FinnGen and UK Biobank were meta-analyzed without heterogeneity. We performed the study from May 15, 2023, to September 15, 2023.

RESULTS

Each 1-SD higher relative protein intake was causally associated with 69% (odds ratio, 0.31; 95% CI, 0.11 to 0.89) lower hypertension risk independent of the effects of other macronutrients, and was the only macronutrient associated with 2.21 (95% CI, 0.52 to 3.91) mm Hg lower pulse pressure, in a unidirectional manner. Higher plant protein-related metabolomic signature (glycine) was associated with lower hypertension risk and pulse pressure, whereas higher animal protein-related metabolomic signatures (leucine, isoleucine, valine, and isovalerylcarnitine [only systolic blood pressure]) were associated with higher hypertension risk, pulse pressure, and systolic blood pressure. The effect of relative protein intake on hypertension was causally mediated by frailty index (mediation proportion, 40.28%), monounsaturated fatty acids (13.81%), saturated fatty acids (11.39%), grip strength (5.34%), standing height (3.99%), and sitting height (3.61%).

CONCLUSION

Higher relative protein intake causally reduces the risk of hypertension, partly mediated by physical fitness and circulating fatty acids.

Genetic analysis from multiple cohorts implies causality between 2200 druggable genes, telomere length, and leukemia

BACKGROUND

Clinical therapeutic targets for leukemia remain to be identified and the causality between leukemia and telomere length is unclear.

METHODS

This work employed cis expression quantitative trait locus (eQTL) for 2,200 druggable genes from the eQTLGen Consortium and genome-wide association studies (GWAS) summary data for telomere length in seven blood cell types from the UK Biobank, Netherlands Cohort as exposures. GWAS data for lymphoid leukemia (LL) and myeloid leukemia (ML) from FinnGen and Lee Lab were used as outcomes for discovery and replication cohorts, respectively. Robust Mendelian randomization (MR) findings were generated from seven MR models and a series of sensitivity analyses. Summary-data-based MR (SMR) analysis and transcriptome-wide association studies (TWAS) were further implemented to verify the association between identified druggable genes and leukemia. Single-cell type expression analysis was employed to identify the specific expression of leukemia casual genes on human bone marrow and peripheral blood immune cells. Multivariable MR analysis, linkage disequilibrium score regression (LDSC), and Bayesian colocalization analysis were performed to further validate the relationship between telomere length and leukemia. Mediation analysis was used to assess the effects of identified druggable genes affecting leukemia via telomere length. Phenome-wide MR (Phe-MR) analysis for assessing the effect of leukemia causal genes and telomere length on 1,403 disease phenotypes.

RESULTS

Combining the results of the meta-analysis for MR estimates from two cohorts, SMR and TWAS analysis, we identified five LL causal genes (TYMP, DSTYK, PPIF, GDF15, FAM20A) and three ML causal genes (LY75, ADA, ABCA2) as promising drug targets for leukemia. Univariable MR analysis showed genetically predicted higher leukocyte telomere length increased the risk of LL (odds ratio [OR] = 2.33, 95 % confidence interval [95 % CI] 1.70-3.18; P = 1.33E-07), and there was no heterogeneity and horizontal pleiotropy. Evidence from the meta-analysis of two cohorts strengthened this finding (OR = 1.88, 95 % CI 1.06-3.05; P = 0.01). Multivariable MR analysis showed the causality between leukocyte telomere length and LL without interference from the other six blood cell telomere length (OR = 2.72, 95 % CI 1.88-3.93; P = 1.23E-07). Evidence from LDSC supported the positive genetic correlation between leukocyte telomere length and LL (rg = 0.309, P = 0.0001). Colocalization analysis revealed that the causality from leukocyte telomere length on LL was driven by the genetic variant rs770526 in the TERT region. The mediation analysis via two-step MR showed that the causal effect from TYMP on LL was partly mediated by leukocyte telomere length, with a mediated proportion of 12 %.

CONCLUSION

Our study identified several druggable genes associated with leukemia risk and provided new insights into the etiology and drug development of leukemia. We also found that genetically predicted higher leukocyte telomere length increased LL risk and its potential mechanism of action.

Causal relationships between dyslexia and the risk of eight dementias

Observational and genetic studies have reported the relationship between dyslexia and Alzheimer's disease (AD). Until now, the causal effect of dyslexia on AD risk has remained unclear. We conducted a two-sample univariable Mendelian randomization (MR) analysis to determine the causal association between dyslexia and the risk of AD, vascular dementia (VD), Lewy body dementia (LBD), and frontotemporal dementia (FTD) and its four subtypes. First, we selected 42 dyslexia genetic variants from a large-scale genome-wide association studies (GWAS) dataset and extracted their corresponding GWAS summary statistics from AD, VD, LBD, and FTD. Second, we selected four MR methods, including inverse-variance weighted (IVW), weighted median, MR-Egger, and MR-PRESSO. Heterogeneity, horizontal pleiotropy, and leave-one-out sensitivity analysis were then used to evaluate the reliability of all causal estimates. We also conducted multivariable MR (MVMR) and mediation analysis to assess the potential mediating role of cognitive performance (CP) or educational achievement (EA) on the causal association between dyslexia and AD. Two MVMR methods, including MV IVW and MV-Egger, and two-step MR were used to perform the analysis. Using IVW, we found a significant causal association between increased dyslexia and increased risk of AD (OR = 1.15, 95% CI: 1.04-1.28, P = 0.006), but not VD, LBD, FTD, or its four subtypes. MR-PRESSO further supported the statistically significant association between dyslexia and AD (OR = 1.15, 95% CI: 1.05-1.27, P = 0.006). All sensitivity analyses confirmed the reliability of causal estimates. Using MV IVW and mediation analysis, we found no causal relationship between dyslexia and AD after adjusting for CP but not EA, CP mediated the total effect of dyslexia on AD with a proportion of 46.32%. We provide genetic evidence to support a causal effect of increased dyslexia on increased risk of AD, which was largely mediated by CP. Reading activity may be a potential intervention strategy for AD by improving cognitive function.

Causal Links Between Systemic Disorders and Keratoconus in European Population

PURPOSE

To establish the presence of a causal linkage between prevalent systemic diseases and keratoconus (KC).

DESIGN

Mendelian randomization (MR) analysis.

METHODS

After an exhaustive screening process, genetic variants linked to various systemic diseases were identified as instrumental variables at the genome-wide significance level. Subsequently, MR analyses were conducted to elucidate their potential causal connection with KC (N = 26,742). The encompassed systemic ailments comprise diabetes, hay fever/allergic rhinitis/eczema, obstructive sleep apnea, thyroid dysfunction, aortic aneurysm, major depressive disorder, inflammatory bowel disease (including Crohn's disease and ulcerative colitis), and mitral valve prolapse. Our study adheres to the principles of Strengthening the Reporting of Observational Studies in Epidemiology Using MR guidelines.

RESULTS

Using inverse variance weighting as the primary MR analysis method, our findings revealed that hay fever/allergic rhinitis/eczema (odds ratio, 10.144; 95% CI, 2.441-42.149; P = .001) and ulcerative colitis (odds ratio, 1.147; 95% CI, 1.054-1.248; P = .002) were associated with an increased risk of KC within the largest population under scrutiny. Conversely, the prolonged hyperglycemic state did not exhibit a potentially protective effect in delaying the pathogenesis of KC, and no correlation was observed between the two (odds ratio, 0.320; 95% CI, 0.029-3.549; P = .353). Also, obstructive sleep apnea, thyroid function, aortic aneurysm, major depressive disorder, Crohn's disease, and mitral valve prolapse did not exhibit a causal association with KC (P > .05 for all comparisons).

CONCLUSIONS

This study indicates an increased risk of KC related to hay fever/allergic rhinitis/eczema and ulcerative colitis, with diabetes not providing a protective effect. These findings may potentially contribute some insights to inform clinical interventions.

Causal effect of gut microbiota on the risk of prostatitis: a two-sample Mendelian randomization study

BACKGROUND

Recent studies demonstrated that chronic prostatitis (CP) is closely related to the gut microbiota (GM). Nevertheless, the causal relationship between GM and CP has not been fully elucidated. Therefore, the two-sample Mendelian randomization (MR) analysis was employed to investigate this association.

METHODS

The summary data of gut microbiota derived from a genome-wide association study (GWAS) involving 18,340 individuals in the MiBioGen study served as the exposure, and the corresponding summary statistics for CP risk, representing the outcome, were obtained from the FinnGen databases (R9). The causal effects between GM and CP were estimated using the inverse-variance weighted (IVW) method supplemented with MR-Egger, weighted median, weighted mode, and simple mode methods. Additionally, the false discovery rate (FDR) correction was performed to adjust results. The detection and quantification of heterogeneity and pleiotropy were accomplished through the MR pleiotropy residual sum and outlier method, Cochran's Q statistics, and MR-Egger regression.

RESULTS

The IVW estimates indicated that a total of 11 GM taxa were related to the risk of CP. Seven of them was correlated with an increased risk of CP, while the remained linked with a decreased risk of CP. However, only Methanobacteria (OR 0.86; 95% CI 0.74-0.99), Methanobacteriales (OR 0.86; 95% CI 0.74-0.99), NB1n (OR 1.16; 95% CI 1.16-1.34), Methanobacteriaceae (OR 0.86; 95% CI 0.74-0.99), Odoribactergenus Odoribacter (OR 1.43; 95% CI 1.05-1.94), and Sutterellagenus Sutterella (OR 1.33; 95% CI 1.01-1.76) still maintain significant association with CP after FDR correction. Consistent directional effects for all analyses were observed in the supplementary methods. Subsequently, sensitivity analyses indicated the absence of heterogeneity, directional pleiotropy, or outliers concerning the causal effect of specific gut microbiota on CP (p > 0.05).

CONCLUSION

Our study demonstrated a gut microbiota-prostate axis, offering crucial data supporting the promising use of the GM as a candidate target for CP prevention, diagnosis, and treatment. There is a necessity for randomized controlled trials to validate the protective effect of the linked GM against the risk of CP, and to further investigate the underlying mechanisms involved.

APOB and CCL17 as mediators in the protective effect of SGLT2 inhibition against myocardial infarction: Insights from proteome-wide mendelian randomization

AIMS

Sodium-glucose cotransporter 2 (SGLT2) inhibitors offer a novel therapeutic avenue for myocardial infarction (MI). However, the exact nature of this relationship and the underlying mechanisms are not fully understood.

METHODS

Utilizing a two-sample Mendelian Randomization (MR) analysis, we elucidated the causal effects stemming from the inhibition of SGLT2 on MI. Then, The pool of 4907 circulating proteins within the plasma proteome were utilized to explore the mediators of SGLT2 inhibitors on MI. Protein-protein network and enrichment analysis were conducted to clarify the potential mechanism. Finally, employing MR analysis and meta-analysis techniques, we systematically assessed the causal associations between SGLT2 inhibition and coronary heart diseases (CHD).

RESULTS

SGLT2 inhibition (per 1 SD decrement in HbA1c) was associated with reduced risk of MI (odds ratio [OR] = 0.462, [95% CI 0.222, 0.958], P = 0.038). Among 4907 circulating proteins, we identified APOB and CCL17 which were related to both SGLT2 inhibition and MI. Mediation analysis showed evidence of the indirect effect of SGLT2 inhibition on MI through APOB (β = -0.557, 95%CI [-1.098, -0.155]) with a mediated proportion of 72%, and CCL17 (β = -0.176, 95%CI [-0.332, -0.056]) with a mediated proportion of 17%. The meta-analysis result showed that SGLT2 inhibition was associated with a lower risk of CHD.

CONCLUSION

Based on proteome-wide mendelian randomization, APOB and CCL17 were seen as mediators in the protective effect of SGLT2 inhibition against myocardial infarction.

Mendelian randomization identifies causal effects of major depressive disorder on accelerated aging

BACKGROUND

Evidence links major depressive disorder (MDD) with aging, but it's unclear if MDD accelerates aging and what factors mediate this transition.

METHODS

Two-sample Mendelian randomization (MR) analyses were applied to estimate the causal association between MDD and frailty index (FI), telomere length (TL), and appendicular lean mass (ALM) from available genome-wide association studies in populations of European ancestry. Furthermore, we conducted mediation MR analyses to assess the mediating effects of 31 lifestyle factors or diseases on the causal relationship between MDD and aging.

RESULTS

MDD was significantly causally associated with increased FI (βIVW = 0.23, 95 % CI = 0.18 to 0.28, p = 1.20 × 10-17), shorter TL (βIVW = -0.04, 95 % CI = -0.07 to -0.01, p = 0.01), and decreased ALM (βIVW = -0.07, 95 % CI = -0.11 to -0.03, p = 3.54 × 10-4). The mediation analysis through two-step MR revealed smoking initiation (9.09 %), hypertension (6.67 %) and heart failure (5.36 %) mediated the causal effect of MDD on FI. Additionally, alcohol use disorders and alcohol dependence on the causal relationship between MDD and TL were found to be 17.52 % and 17.13 % respectively.

LIMITATIONS

Confounding, statistical power, and Euro-centric focus limit generalization.

CONCLUSION

Overall, individuals with MDD may be at a higher risk of experiencing premature aging, and this risk is partially influenced by the pathways involving smoking, alcohol use, and cardiovascular health. It underscores the importance of early intervention and comprehensive health management in individuals with MDD to promote healthy aging and overall well-being.

Genetic causality and metabolite pathway identifying the relationship of blood metabolites and psoriasis

BACKGROUND

Psoriasis is a chronic inflammatory disease that causes significant disability. However, little is known about the underlying metabolic mechanisms of psoriasis. Our study aims to investigate the causality of 975 blood metabolites with the risk of psoriasis.

MATERIALS AND METHODS

We mainly applied genetic analysis to explore the possible associations between 975 blood metabolites and psoriasis. The inverse variance weighted (IVW) method was used as the primary analysis to assess the possible association of blood metabolites with psoriasis. Moreover, generalized summary-data-based Mendelian randomization (GSMR) was used as a supplementary analysis. In addition, linkage disequilibrium score regression (LDSC) was used to investigate their genetic correction further. Metabolic pathway analysis of the most suggested metabolites was also performed using MetaboAnalyst 5.0.

RESULTS

In our primary analysis, 17 metabolites, including unsaturated fatty acids, phospholipids, and triglycerides traits, were selected as potential factors in psoriasis, with odd ratios (OR) ranging from 0.986 to 1.01. The GSMR method confirmed the above results (β = 0.001, p < 0.05). LDSC analysis mainly suggested the genetic correlation of psoriasis with genetic correlations (rg) from 0.088 to 0.155. Based on the selected metabolites, metabolic pathway analysis suggested seven metabolic pathways including ketone body that may be prominent pathways for metabolites in psoriasis.

CONCLUSION

Our study supports the causal role of unsaturated fatty acid properties and lipid traits with psoriasis. These properties may be regulated by the ketone body metabolic pathway.

SGLT2 inhibition, circulating proteins, and insomnia: A mendelian randomization study

BACKGROUND

Sodium-glucose cotransporter 2 inhibitors (SGLT2i) initially emerged as oral antidiabetic medication but were subsequently discovered to exhibit pleiotropic actions. Insomnia is a prevalent and debilitating sleep disorder. To date, the causality between SGLT2 inhibitors and insomnia remains unclear. This study aims to evaluate the causality between SGLT2 inhibitors and insomnia and identify potential plasma protein mediators.

METHODS

Using a two-sample Mendelian Randomization (MR) analysis, we estimated the causality of SGLT2 inhibition on insomnia and sleep duration. Additionally, employing a two-step and proteome-wide MR analysis, we evaluated the causal link of SGLT2 inhibition on 4907 circulating proteins and the causality of SGLT2 inhibition-driven plasma proteins on insomnia. We applied a false discovery rate (FDR) correction for multiple comparisons. Furthermore, mediation analyses were used to identify plasma proteins that mediate the effects of SGLT2 inhibition on insomnia.

RESULTS

SGLT2 inhibition was negatively correlated with insomnia (odds ratio [OR] = 0.791, 95 % confidence interval [CI] [0.715, 0.876], P = 5.579*10^-6) and positively correlated with sleep duration (β = 0.186, 95 % CI [0.059, 0.314], P = 0.004). Among the 4907 circulating proteins, diadenosine tetraphosphatase (Ap4A) was identified as being linked to both SGLT2 inhibition and insomnia. Mediation analysis indicated that the effect of SGLT2 inhibition on insomnia partially operates through Ap4A (β = -0.018, 95 % CI [-0.036, -0.005], P = 0.023), with a mediation proportion of 7.7 %.

CONCLUSION

The study indicated a causality between SGLT2 inhibition and insomnia, with plasma Ap4A potentially serving as a mediator.

Bi-directional two-sample Mendelian randomization identifies causal association of depression with temporomandibular disorders

BACKGROUND

Depression and anxiety have been suggested to be associated with temporomandibular disorders (TMD) in observational studies. However, the causal association and the direction in the relationship between depression/anxiety and TMD remain unknown.

OBJECTIVES

This study investigated the potential causal relationship between depression/anxiety and TMD with two-sample bi-directional Mendelian randomization (MR).

METHODS

Summary statistics of depression (N = 500 199), anxiety disorder (N = 17 310) and TMD (N = 195 930) were sourced from large-scale genome-wide association studies (GWAS). The primary Mendelian randomization (MR) estimation employed the inverse-variance weighted meta-analysis (IVW). Additional MR sensitivity methods and multivariate MR (MVMR) were applied to address pleiotropy.

RESULTS

IVW results indicated a causal effect of genetically predicted depression on TMD (OR = 1.887, 95% CI = 1.504-2.367, p < .001), which was supported by other sensitivity MR approaches. MVMR results suggested that the negative effect of depression on TMD persisted after conditioning on other potential confounders. The association of anxiety disorder with TMD was not supported by our findings. In the reverse direction, we did not find compelling evidence suggesting the causal effect of TMD on depression and anxiety disorder.

CONCLUSIONS

The present study suggests a potential causal association between genetic liability for depression and the risk of TMD. Our MR findings align with prior epidemiological research, underscoring the significance of early detection and prevention of depression in the treatment of TMD.

Causal effect of sarcopenia-related traits on the occurrence and prognosis of breast cancer - A bidirectional and multivariable Mendelian randomization study

Introduction

Background and aims: although sarcopenia is associated with several types of cancer, there is limited research regarding its effect on breast cancer. We aimed to explore the causality between sarcopenia-related traits and the incidence and prognosis of breast cancer. Methods: two-sample bidirectional and multivariate Mendelian randomization (MR) analyses were utilized in this study. Genome-wide association studies were used to genetically identify sarcopenia-related traits, such as appendicular lean mass, grip strength of both hands, and walking pace. Data on the incidence and prognosis of breast cancer were collected from two extensive cohort studies. Multivariate MR analysis was used to adjust for body mass index, waist circumference, and whole-body fat mass. The primary method used for analysis was inverse-variance weighted analysis. Results: a significant association was found between appendicular lean mass and ER- breast cancer (OR = 0.873, 95 % CI: 0.817-0.933, p = 6.570 × 10-5). Increased grip strength of the left hand was associated with a reduced risk of ER- breast cancer (OR = 0.744, 95 % CI: 0.579-0.958, p = 0.022). Stronger grip strength of the right hand was associated with prolonged survival time of ER+ breast cancer patients (OR = 0.463, 95 % CI: 0.242-0.882, p = 0.019). In the multivariable MR analysis, appendicular lean mass, grip strength of both hands, and walking pace were still genetically associated with the development of total breast cancer and ER-/+ breast cancer. Conclusions: several sarcopenia-related traits were genetically associated with the occurrence and prognosis of breast cancer. It is crucial for elderly women to increase their strength and muscle mass to help prevent breast cancer.

Genetic evidence for the causal relationships between migraine, dementia, and longitudinal brain atrophy

BACKGROUND

Migraine is a neurological disease with a significant genetic component and is characterized by recurrent and prolonged episodes of headache. Previous epidemiological studies have reported a higher risk of dementia in migraine patients. Neuroimaging studies have also shown structural brain atrophy in regions that are common to migraine and dementia. However, these studies are observational and cannot establish causality. The present study aims to explore the genetic causal relationship between migraine and dementia, as well as the mediation roles of brain structural changes in this association using Mendelian randomization (MR).

METHODS

We collected the genome-wide association study (GWAS) summary statistics of migraine and its two subtypes, as well as four common types of dementia, including Alzheimer's disease (AD), vascular dementia, frontotemporal dementia, and Lewy body dementia. In addition, we collected the GWAS summary statistics of seven longitudinal brain measures that characterize brain structural alterations with age. Using these GWAS, we performed Two-sample MR analyses to investigate the causal effects of migraine and its two subtypes on dementia and brain structural changes. To explore the possible mediation of brain structural changes between migraine and dementia, we conducted a two-step MR mediation analysis.

RESULTS

The MR analysis demonstrated a significant association between genetically predicted migraine and an increased risk of AD (OR = 1.097, 95% CI = [1.040, 1.158], p = 7.03 × 10- 4). Moreover, migraine significantly accelerated annual atrophy of the total cortical surface area (-65.588 cm2 per year, 95% CI = [-103.112, -28.064], p = 6.13 × 10- 4) and thalamic volume (-9.507 cm3 per year, 95% CI = [-15.512, -3.502], p = 1.91 × 10- 3). The migraine without aura (MO) subtype increased the risk of AD (OR = 1.091, 95% CI = [1.059, 1.123], p = 6.95 × 10- 9) and accelerated annual atrophy of the total cortical surface area (-31.401 cm2 per year, 95% CI = [-43.990, -18.811], p = 1.02 × 10- 6). The two-step MR mediation analysis revealed that thalamic atrophy partly mediated the causal effect of migraine on AD, accounting for 28.2% of the total effect.

DISCUSSION

This comprehensive MR study provided genetic evidence for the causal effect of migraine on AD and identified longitudinal thalamic atrophy as a potential mediator in this association. These findings may inform brain intervention targets to prevent AD risk in migraine patients.

Risk of major depressive increases with increasing frequency of alcohol drinking: a bidirectional two-sample Mendelian randomization analysis

Introduction

A growing body of evidence suggests that alcohol use disorders coexist with depression. However, the causal relationship between alcohol consumption and depression remains a topic of controversy.

Methods

We conducted a two-sample two-way Mendelian randomization analysis using genetic variants associated with alcohol use and major depressive disorder from a genome-wide association study.

Results

Our research indicates that drinking alcohol can reduce the risk of major depression (odds ratio: 0.71, 95% confidence interval: 0.54~0.93, p = 0.01), while increasing the frequency of drinking can increase the risk of major depression (odds ratio: 1.09, 95% confidence interval: 1.00~1.18, p = 0.04). Furthermore, our multivariate MR analysis demonstrated that even after accounting for different types of drinking, the promoting effect of drinking frequency on the likelihood of developing major depression still persists (odds ratio: 1.13, 95% confidence interval: 1.04~1.23, p = 0.005). Additionally, mediation analysis using a two-step MR approach revealed that this effect is partially mediated by the adiposity index, with a mediated proportion of 37.5% (95% confidence interval: 0.22 to 0.38).

Discussion

In this study, we found that alcohol consumption can alleviate major depression, while alcohol intake frequency can aggravate it.These findings have important implications for the development of prevention and intervention strategies targeting alcohol-related depression.

Association between sleep traits and sarcopenia-related traits: A two-sample bidirectional Mendelian randomization study

AIM

Despite limited evidence regarding the impact of sleep quality on sarcopenia, it is widely recognized as being associated with various diseases. This study aimed to explore the causal relationship between sleep traits and sarcopenia-related traits.

METHODS

This study utilized a two-sample bidirectional Mendelian randomization analysis. Genetic genome-wide summary data of sleep quality indicators, including chronotype, morning wake-up time, sleep duration, daytime napping, insomnia and daytime dozing, were used. Data on sarcopenia-related traits, such as appendicular lean mass, grip strength of both hands, walking pace and waist circumference, were collected from a large cohort study. The primary method used was the inverse-variance weighted analysis.

RESULTS

A causal association was found between chronotype and appendicular lean mass (odds ratio [OR] 1.019, 95% confidence interval [CI] 1.016-1.211, P = 0.021). Napping during the day was connected with walking pace (OR 0.879, 95% CI 0.834-0.928, P = 2.289 × 10-6) and waist circumference (OR 1.234, 95% CI 1.081-1.408, P = 0.002). Insomnia was related to lower grip strength of the right hand (OR 0.844, 95% CI 0.747-0.954, P = 0.007), left hand (OR 0.836, 95% CI 0.742-0.943, P = 0.003), as well as walking pace (OR 0.871, 95% CI 0.798-0.951, P = 0.002). Furthermore, the reverse Mendelian randomization analysis showed associations between certain sarcopenia-related traits and poor sleep quality.

CONCLUSIONS

Some sleep traits were associated with the occurrence of sarcopenia. These findings emphasized the significance of prioritizing sleep quality as a preventive measure against sarcopenia. Geriatr Gerontol Int 2024; 24: 537-545.