Association Studies In Populations Research Articles

CATSPER2 and SPEF2 are potential molecular markers for boar sperm quality: a population association study

CATSPER2 and SPEF2 are potential molecular markers for boar sperm quality: a population association study

Modifiable factors mediating the effects of educational attainment on gestational diabetes mellitus: A two-step Mendelian randomization study.

Although there is currently a wealth of evidence to indicate that maternal educational attainment is associated with gestational diabetes mellitus (GDM), the specific modifiable risk factors that mediate the causal relationship between these two variables have yet to be identified. To identify the specific modifiable risk factors that mediate the causal relationship between the level of maternal education and GDM. Mendelian randomization (MR) was conducted using data from genome-wide association studies of European populations. We initially performed a two-sample MR analysis using data on genetic variants associated with the duration of education as instruments, and subsequently adopted a two-step MR approach using metabolic and lifestyle factors as mediators to examine the mechanisms underlying the relationship between the level of maternal education and risk of developing GDM. In addition, we calculated the proportions of total causal effects mediated by identified metabolic and lifestyle factors. A genetically predicted higher educational attainment was found to be associated with a lower risk of developing GDM (OR: 0.71, 95%CI: 0.60-0.84). Among the metabolic factors assessed, four emerged as potential mediators of the education-GDM association, which, ranked by mediated proportions, were as follows: Waist-to-hip-ratio (31.56%, 95%CI: 12.38%-50.70%), body mass index (19.20%, 95%CI: 12.03%-26.42%), high-density lipoprotein cholesterol (12.81%, 95%CI: 8.65%-17.05%), and apolipoprotein A-1 (7.70%, 95%CI: 4.32%-11.05%). These findings proved to be robust to sensitivity analyses. Our findings indicate a causal relationship between lower levels of maternal education and the risk of developing GDM can be partly explained by adverse metabolic profiles.

Causality between neuroticism personality clusters and female reproductive diseases in European population: a two-sample bidirectional mendelian randomization study

BackgroundThe causality between neuroticism, a personality trait characterized by the tendency to experience negative emotions, and female reproductive diseases remains unclear. To provide evidence for the development of effective screening and prevention strategies, this study employed Mendelian randomization (MR) to investigate the causality between neuroticism clusters and female reproductive diseases.MethodsInstrumental variables were obtained from large-scale genome-wide association studies of populations of European descent involving three neuroticism clusters (depressed affect, worry, sensitivity to environmental stress, and adversity [SESA]) in the Complex Trait Genetics database and six female reproductive diseases (infertility, polycystic ovary syndrome [PCOS], spontaneous abortion, recurrent spontaneous abortion, endometriosis, and uterine fibroids) in the FinnGen database. The bidirectional two-sample MR analysis was conducted using the inverse variance-weighted, weighted median, and MR-Egger methods, whereas the sensitivity analysis was conducted using the Cochran’s Q-test, MR-Egger intercept, and leave-one-out analysis.ResultsIn the forward analysis, genetically predicted depressed affect and worry components of neuroticism significantly increased the risk of infertility (depressed affect: odds ratio [OR] = 1.399, 95% confidence interval [CI]: 1.054–1.856, p = 0.020; worry: OR = 1.587, 95% CI: 1.229–2.049, p = 0.000) and endometriosis (depressed affect: OR = 1.611, 95% CI: 1.234–2.102, p = 0.000; worry: OR = 1.812, 95% CI: 1.405–2.338, p = 0.000). Genetically predicted SESA component of neuroticism increased only the risk of endometriosis (OR = 1.524, 95% CI: 1.104–2.103, p = 0.010). In the reverse analysis, genetically predicted PCOS was causally associated with an increased risk of the worry component of neuroticism (Beta = 0.009, 95% CI: 0.003–0.016, p = 0.003).ConclusionsThe MR study showed that the three neuroticism personality clusters had definite causal effects on at least one specific female reproductive disease. Moreover, PCOS may increase the risk of the worry component of neuroticism. This finding suggests the need to screen for specific female reproductive diseases in populations with high neuroticism and assess the psychological status of patients with PCOS.

Causal links between immune cells and asthma: Insights from a Mendelian Randomization analysis

Objectives Recent studies suggest immunophenotypes may play a role in asthma, but their causal relationship has not been thoroughly examined. Methods We used single nucleotide polymorphism (SNP)-derived instrumental variables. Summary data from 731 immune cell profiles and asthma cases were analyzed from genome-wide association studies (GWAS) of European populations. Mendelian Randomization (MR) analyses included inverse variance weighted (IVW), weighted median, and MR–Egger methods. Pleiotropy was assessed using the MR-Egger intercept and MR pleiotropy residual sum and outlier (MR-PRESSO) tests. Reverse MR analysis explored bidirectional causation between asthma and immunophenotypes. All statistical analyses were conducted using R software. Results MR analysis identified 108 immune signatures potentially contributing to asthma. Two immunophenotypes were significantly associated with asthma risk: CD4+ secreting Treg cells in allergic asthma (ORIVW = 1.078; 95% CI: 1.036–1.122; PIVW = 0.0002) and IgD + CD38− %lymphocyte cells in non-allergic asthma (ORIVW = 1.123; 95% CI: 1.057–1.194; PIVW = 0.0002). Conclusions This study highlights the causal associations between specific immunophenotypes and asthma risk, providing new insights into asthma pathogenesis.

Causal Associations Between Tea Consumption and REM Sleep Behavior Disorder: A Mendelian Randomization Study.

Previous studies have shown that tea consumption may have a protective effect against neurodegenerative diseases. However, the exact causal relationship between tea consumption and the precursor stages of certain neurodegenerative diseases, namely REM sleep behavior disorder (RBD), remains unclear. To evaluate the causal association between tea consumption and RBD, we employed a Mendelian randomization study. We identified genetic instrumental variables that are significantly associated with tea consumption through genome-wide association studies (GWAS) in European populations. Bidirectional two-sample Mendelian randomization was utilized to determine the causal relationship between tea consumption and RBD, while sensitivity analyses were further employed to evaluate the robustness of the results. The multivariate Mendelian randomization method was used to assess the influence of relevant confounding factors on the results. In the MR analysis using the inverse variance weighting method, a significant causal relationship between tea consumption and RBD was observed (OR=0.046, 95% CI 0.004-0.563, p=0.016). The consistency of findings across maximum likelihood, MR PRESSO, and multivariate MR after adjusting for potential confounding further supports this causal association. Sensitivity analyses revealed no evidence of heterogeneity or pleiotropy. The findings of our study demonstrate a robust causal association between tea consumption and RBD, indicating that tea consumption may serve as a protective factor against the development of RBD.

Causal associations between insulin and Lp(a) levels in Caucasian population: a Mendelian randomization study

BackgroundNumerous observational studies have demonstrated that circulating lipoprotein(a) [Lp(a)] might be inversely related to the risk of type 2 diabetes (T2D). However, recent Mendelian randomization (MR) studies do not consistently support this association. The results of in vitro research suggest that high insulin concentrations can suppress Lp(a) levels by affecting apolipoprotein(a) [apo(a)] synthesis. This study aimed to identify the relationship between genetically predicted insulin concentrations and Lp(a) levels, which may partly explain the associations between low Lp(a) levels and increased risk of T2D.MethodsIndependent genetic variants strongly associated with fasting insulin levels were identified from meta-analyses of genome-wide association studies in European populations (GWASs) (N = 151,013). Summary level data for Lp(a) in the population of European ancestry were acquired from a GWAS in the UK Biobank (N = 361,194). The inverse-variance weighted (IVW) method approach was applied to perform two-sample summary-level MR. Robust methods for sensitivity analysis were utilized, such as MR‒Egger, the weighted median (WME) method, MR pleiotropy residual sum and outlier (MR-PRESSO), leave-one-out analysis, and MR Steiger.ResultsGenetically predicted fasting insulin levels were negatively associated with Lp(a) levels (β = − 0.15, SE = 0.05, P = 0.003). The sensitivity analysis revealed that WME (β = − 0.26, SE = 0.07, P = 0.0002), but not MR‒Egger (β = − 0.22, SE = 0.13, P = 0.11), supported a causal relationship between genetically predisposed insulin levels and Lp(a).ConclusionOur MR study provides robust evidence supporting the association between genetically predicted increased insulin concentrations and decreased concentrations of Lp(a). These findings suggest that hyperinsulinaemia, which typically accompanies T2D, can partially explain the inverse relationship between low Lp(a) concentrations and an increased risk of T2D.

Mendelian randomization analysis reveals the combined effects of epigenetics and telomere biology in hematologic cancers

BackgroundTelomere shortening and epigenetic modifications are key factors in aging and hematologic diseases. This study investigates the relationship of telomere length and epigenetic age acceleration (EAA) with hematologic cancers, blood cells, and biochemical markers through the epigenetic clocks.MethodsThis study primarily utilizes genome-wide association studies of populations of European descent as instrumental variables, exploring the causal relationships between exposures and outcomes through a bidirectional two-sample Mendelian randomization (MR) approach. MR techniques include inverse variance weighted (IVW), MR Egger, and weighted median modes. Heterogeneity and pleiotropy in MR are assessed using Cochran's Q test and the MR Egger intercept, with the robustness of the conclusions further validated by multivariable MR (MVMR).ResultsOur research shows that longer telomere lengths significantly increase the risk of multiple myeloma, leukemia, and lymphoma (OR > 1, P < 0.05) and establish a causal relationship between telomere length and red blood cell indices such as RBC (OR = 1.121, PIVW = 0.034), MCH (OR = 0.801, PIVW = 2.046e-06), MCV (OR = 0.801, PIVW = 0.001), and MCHC (OR = 0.813, PIVW = 0.002). Additionally, MVMR analysis revealed an association between DNA methylation PhenoAge acceleration and alkaline phosphatase (OR = 1.026, PIVW = 0.007).ConclusionThe study clarifies the relationships between telomere length, EAA, and hematological malignancies, further emphasizing the prognostic significance of telomere length and EAA. This deepens our understanding of the pathogenesis of hematological diseases, which can inform risk assessment and therapeutic strategies.

Impact of thyroid function on coagulation and venous thromboembolism: a two-sample mendelian randomization study.

The association between thyroid function, coagulation and venous thromboembolism (VTE) has been reported in observational studies with conflicting findings. This study aimed to elucidate the causal effects of thyroid function on coagulation and VTE from a genetic perspective. Two sample Mendelian randomization analysis was conducted using summary statistics from genome-wide association studies in a European population. Coagulation status was associated with nine coagulation-related factors (F VIII, F IX, F XI, Fibrinogen, Antithrombin-III, Thrombomodulin, Plasminogen activator inhibitor-1, Protein C and Protein S). Inverse variance weighting with random effect method was used as the main analytic approach with MR-Egger, weighted median, simple mode and weighted mode methods serving as complements. Sensitivity analyses including heterogeneity test, horizontal pleiotropy test and leave-one-out analysis were conducted to further assess the reliability of results. No genetic causal effects of thyroid function on VTE (including pulmonary embolism and deep venous thrombosis) were found. Genetically, hyperthyroidism was suggestively related to decreased Antithrombin-III (β: -0.04 [95% CI: -0.06 to - 0.01], p = 0.010) and Protein C (β: -0.03 [95% CI: -0.06 to 0.00], p = 0.045). No notable associations were observed between other thyroid function parameters and coagulation-related factors. We provide suggestive genetic evidence supporting the causal effect of hyperthyroidism on decreased level of anticoagulant factors including Antithrombin-III and Protein C. However, whether this genetic causality could lead to clinically significant hypercoagulable state and increased risk of VTE in hyperthyroid population needs to be further addressed.

Evaluation of the associations of interlukin-7 genetic variants with toxicity and efficacy of immune checkpoint inhibitors: A replication study of a Japanese population, based on the findings of a European genome-wide association study.

Recent genome-wide association studies of European populations have identified rs16906115, a single-nucleotide polymorphism in the interleukin-7 gene, as a predictor of immune-related adverse events (irAEs) and the therapeutic efficacy of immune checkpoint inhibitors. We evaluated this single-nucleotide polymorphism in a Japanese population. From January 2021, we stored host DNA from individuals who received various types of immune checkpoint inhibitors. From this population, we categorized 510 participants into cases (grade ≥2 irAEs) and controls (received ≥3 immune checkpoint inhibitor doses, follow-up ≥12weeks, no irAEs), and divided 339 hepatocellular carcinoma patients treated with atezolizumab/bevacizumab into responders and non-responders, evaluated using the modified response evaluation criteria in solid tumors. We compared the minor allele frequencies of rs16906115 between cases and controls, and responders and non-responders. In the irAE prediction analysis of 234 cases and 276 controls, the minor allele frequency was 0.244 in the case group and 0.265 in the control group. This difference is not significant. In the analysis predicting the therapeutic efficacy for hepatocellular carcinoma patients, the responders had a significantly lower minor allele frequency of 0.220, compared with 0.300 for the non-responders (p=0.022). Univariate and multivariate analyses identified the minor allele homozygosity as a significant predictor of treatment response, with odds ratios of 0.292 (p=0.015) in the univariate analysis and 0.315 (p=0.023) in the multivariate analysis. In our Japanese cohort, no association was found between the rs16906115 minor allele and irAEs or treatment efficacy. The minor allele homozygosity may be associated with a negative therapeutic outcome. UMIN Clinical Trials Registry with the number UMIN000043798.

Mendelian randomization evidence for the causal effect of mental well-being on healthy aging.

Mental well-being relates to multitudinous lifestyle behaviours and morbidities and underpins healthy aging. Thus far, causal evidence on whether and in what pattern mental well-being impacts healthy aging and the underlying mediating pathways is unknown. Applying genetic instruments of the well-being spectrum and its four dimensions including life satisfaction, positive affect, neuroticism and depressive symptoms (n = 80,852 to 2,370,390), we performed two-sample Mendelian randomization analyses to estimate the causal effect of mental well-being on the genetically independent phenotype of aging (aging-GIP), a robust and representative aging phenotype, and its components including resilience, self-rated health, healthspan, parental lifespan and longevity (n = 36,745 to 1,012,240). Analyses were adjusted for income, education and occupation. All the data were from the largest available genome-wide association studies in populations of European descent. Better mental well-being spectrum (each one Z-score higher) was causally associated with a higher aging-GIP (β [95% confidence interval (CI)] in different models ranging from 1.00 [0.82-1.18] to 1.07 [0.91-1.24] standard deviations (s.d.)) independent of socioeconomic indicators. Similar association patterns were seen for resilience (β [95% CI] ranging from 0.97 [0.82-1.12] to 1.04 [0.91-1.17] s.d.), self-rated health (0.61 [0.43-0.79] to 0.76 [0.59-0.93] points), healthspan (odds ratio [95% CI] ranging from 1.23 [1.02-1.48] to 1.35 [1.11-1.65]) and parental lifespan (1.77 [0.010-3.54] to 2.95 [1.13-4.76] years). Two-step Mendelian randomization mediation analyses identified 33 out of 106 candidates as mediators between the well-being spectrum and the aging-GIP: mainly lifestyles (for example, TV watching and smoking), behaviours (for example, medication use) and diseases (for example, heart failure, attention-deficit hyperactivity disorder, stroke, coronary atherosclerosis and ischaemic heart disease), each exhibiting a mediation proportion of >5%. These findings underscore the importance of mental well-being in promoting healthy aging and inform preventive targets for bridging aging disparities attributable to suboptimal mental health.

Associations of lipids and lipid-modifying drug target genes with atrial fibrillation risk based on genomic data

BackgroundThe causal associations of lipids and the drug target genes with atrial fibrillation (AF) risk remain obscure. We aimed to investigate the causal associations using genetic evidence.MethodsMendelian randomization (MR) analyses were conducted using summary-level genome-wide association studies (GWASs) in European and East Asian populations. Lipid profiles (low-density lipoprotein cholesterol, triglyceride, and lipoprotein[a]) and lipid-modifying drug target genes (3-hydroxy-3-methylglutaryl-CoA reductase, proprotein convertase subtilisin/kexin type 9, NPC1-like intracellular cholesterol transporter 1, apolipoprotein C3, angiopoietin-like 3, and lipoprotein[a]) were used as exposures. AF was used as an outcome. The inverse variance weighted method was applied as the primary method. Summary-data-based Mendelian randomization analyses were performed for further validation using expression quantitative trait loci data. Mediation analyses were conducted to explore the indirect effect of coronary heart disease.ResultsIn the European population, MR analyses demonstrated that elevated levels of lipoprotein(a) increased AF risk. Moreover, analyses focusing on drug targets revealed that the genetically proxied target gene LPA, which simulates the effects of drug intervention by reducing lipoprotein(a), exhibited an association with AF risk. This association was validated in independent datasets. There were no consistent and significant associations observed for other traits when analyzed in different datasets. This finding was also corroborated by Summary-data-based Mendelian randomization analyses between LPA and AF. Mediation analyses revealed that coronary heart disease plays a mediating role in this association. However, in the East Asian population, no statistically significant evidence was observed to support these associations.ConclusionsThis study provided genetic evidence that Lp(a) may be a causal factor for AF and that LPA may represent a promising pharmacological target for preventing AF in the European population.

Genome-wide linkage and association of novel genes and pathways with type 2 diabetes in Italian families

BackgroundType 2 diabetes mellitus (T2D) stands as one of the most prevalent chronic diseases globally, posing substantial health and economic burdens on society. Within the spectrum of T2D, familial cases emerge as a distinct entity characterized by a strong familial clustering of the disease. This phenomenon has long suggested that genetics contributes substantially to T2D susceptibility, motivating extensive research into the genetic determinants of familial T2D. MethodsWe recruited 212 multigenerational Italian families with multiple cases of T2D. The families were genotyped using genomic array (≥ 600k) derived from the UK Biobank Axiom Array platform. Informative markers were tested via Pseudomarker for linkage to and linkage disequilibrium (i.e., linkage joint to association) with T2D across the following models: dominant with complete penetrance (D1), dominant with incomplete penetrance (D2), recessive with complete penetrance (R1), and recessive with incomplete penetrance (R2). ResultsWe identified a total of 566 variants reaching genome-wide significant (P < 0.00005) linkage and/or association to/with the risk of T2D in Italian families. Of the 355 genes identified in our study, 341 (96%) are novel and have not been reported with T2D or any of its related phenotypes (i.e., obesity, metabolic syndrome, insulin resistance, polycystic ovary syndrome, and hyperglycemia). ConclusionOur study constitutes the first familial T2D-linkage and association study in the Italian population. However, the functional relevance of the novel variants and genes reported in our study remains to be explored.

The causal relationship between vitiligo and autoimmune thyroid diseases: A bidirectional two-sample Mendelian randomization analysis.

Vitiligo is an acquired autoimmune depigmented disorder characterized by the presence of white and well-defined patches on the skin, mucous membrane, or both. It is associated with a significant disease burden and has a profoundly impacts patients' quality of life. Autoimmune thyroid diseases (AITDs) result from an autoimmune system dysregulation, leading to an erroneous immune attack on the thyroid gland. Previous observational and epidemiological studies have suggested the association between vitiligo and AITDs. However, the bidirectional cause-effect relationship between vitiligo and AITDs has not been formally assessed. Two-sample bidirectional Mendelian randomization (MR) analysis was conducted to explore potential causal relationships between genetically increased risk of vitiligo and AITDs, using summary statistics from genome-wide association studies in European populations. Causal effects were primarily estimated using the inverse variance weighted method, and additional quality control was performed using the MR-Egger, weighted median, simple mode, and weight mode methods. Sensitivity analysis was conducted to assess the robustness of the results. The forward MR analysis showed a positive causal relationship between vitiligo and autoimmune thyroiditis (AIT), autoimmune hyperthyroidism (AIH), and Graves' disease (GD). The odds ratio (OR) were 1.17 (95% CI, 1.01-1.35; p=0.04), 1.12 (95% CI, 1.03-1.22; p=0.01), and 1.13 (95% CI, 1.06-1.20; p<0.01), respectively. In the reverse MR analysis, a positive causal relationship was found between AIT and vitiligo, with an OR of 1.10 (95% CI, 1.01-1.35; p=0.04). However, no causal relationship was observed between AIH (p=0.10) or GD (p=0.61) and vitiligo. Sensitivity analysis revealed no evidence of horizontal pleiotropy or heterogeneity. The genetic-level investigation provides evidence of a genetic causal association between susceptibility to vitiligo and an increased risk of AITDs. Additionally, the results demonstrate a genetic causal association between susceptibility to AIT and an increased risk of vitiligo, while not indicating a similar association with susceptibility to AIH or GD.

Causal association between systemic lupus erythematosus and primary biliary cholangitis: A bidirectional Mendelian randomization study.

An association has been observed between systemic lupus erythematosus (SLE) and primary biliary cholangitis (PBC) in observational studies, however, the exact causal link remains unclear. We aim to evaluate the causal relationships between SLE and PBC through bidirectional Mendelian randomization (MR). Single-nucleotide polymorphisms (SNPs) were selected as instrumental variables from publicly accessible genome-wide association studies (GWAS) in European populations. The PBC and SLE GWAS data were obtained from the MRC IEU Open GWAS database, consisting of 24,510 and 14,267 samples, respectively. After a series of quality control and outlier removal, inverse variance weighted was used as the primary approach to evaluate the causal association between SLE and PBC. The horizontal pleiotropy and heterogeneity were examined by the MR-Egger intercept test and Cochran Q value, respectively. Seven SNPs were included to examine the causal effect of SLE on PBC. Genetically predicted SLE may increase the risk of PBC development, with an odds ratio (OR) of 1.324 (95% confidence interval [CI] 1.220 ∼ 1.437, P ˂ .001). Twenty SNPs were included to explore the causal effect of PBC on SLE. Genetically predicted PBC may increase the risk of SLE development, with an OR of 1.414 (95% CI 1.323 ∼ 1.511, P ˂ .001). Horizontal pleiotropy and heterogeneity were absent (P > .05) among SNPs. The robustness of our results was further enhanced by using the leave-one-out method. Our research has provided new insights into SLE and PBC, indicating bidirectional causal associations between the 2 diseases. These findings offer valuable contributions to future clinical studies.

Genetic Complexities of Cerebral Small Vessel Disease, Blood Pressure, and Dementia.

Vascular disease is a treatable contributor to dementia risk, but the role of specific markers remains unclear, making prevention strategies uncertain. To investigate the causal association between white matter hyperintensity (WMH) burden, clinical stroke, blood pressure (BP), and dementia risk, while accounting for potential epidemiologic biases. This study first examined the association of genetically determined WMH burden, stroke, and BP levels with Alzheimer disease (AD) in a 2-sample mendelian randomization (2SMR) framework. Second, using population-based studies (1979-2018) with prospective dementia surveillance, the genetic association of WMH, stroke, and BP with incident all-cause dementia was examined. Data analysis was performed from July 26, 2020, through July 24, 2022. Genetically determined WMH burden and BP levels, as well as genetic liability to stroke derived from genome-wide association studies (GWASs) in European ancestry populations. The association of genetic instruments for WMH, stroke, and BP with dementia was studied using GWASs of AD (defined clinically and additionally meta-analyzed including both clinically diagnosed AD and AD defined based on parental history [AD-meta]) for 2SMR and incident all-cause dementia for longitudinal analyses. In 2SMR (summary statistics-based) analyses using AD GWASs with up to 75 024 AD cases (mean [SD] age at AD onset, 75.5 [4.4] years; 56.9% women), larger WMH burden showed evidence for a causal association with increased risk of AD (odds ratio [OR], 1.43; 95% CI, 1.10-1.86; P = .007, per unit increase in WMH risk alleles) and AD-meta (OR, 1.19; 95% CI, 1.06-1.34; P = .008), after accounting for pulse pressure for the former. Blood pressure traits showed evidence for a protective association with AD, with evidence for confounding by shared genetic instruments. In the longitudinal (individual-level data) analyses involving 10 699 incident all-cause dementia cases (mean [SD] age at dementia diagnosis, 74.4 [9.1] years; 55.4% women), no significant association was observed between larger WMH burden and incident all-cause dementia (hazard ratio [HR], 1.02; 95% CI, 1.00-1.04; P = .07). Although all exposures were associated with mortality, with the strongest association observed for systolic BP (HR, 1.04; 95% CI, 1.03-1.06; P = 1.9 × 10-14), there was no evidence for selective survival bias during follow-up using illness-death models. In secondary analyses using polygenic scores, the association of genetic liability to stroke, but not genetically determined WMH, with dementia outcomes was attenuated after adjusting for interim stroke. These findings suggest that WMH is a primary vascular factor associated with dementia risk, emphasizing its significance in preventive strategies for dementia. Future studies are warranted to examine whether this finding can be generalized to non-European populations.

Exploring the causal relationships between rheumatoid arthritis and oral phenotypes: a genetic correlation and Mendelian randomization study.

Rheumatoid arthritis (RA) frequently presents with oral manifestations, including gingival inflammation, loose teeth, and mouth ulcers; however, the causal connections between these conditions remain unclear. This study aims to explore the genetic correlations and causal relationships between RA and prevalent oral phenotypes. Using summary data from genome-wide association studies of European populations, a cross-trait linkage disequilibrium score regression was conducted to estimate the genetic correlations between RA and six oral phenotypes. Subsequently, a two-sample Mendelian randomization (MR) approach was employed to assess the causal relationships, corroborated by various sensitivity analyses. Heterogeneity was addressed through the RadialMR method, while potential covariates were corrected using the multivariable MR approach. A significant negative genetic correlation was detected between RA and denture usage (rg = -0.192, p = 4.88 × 10-8). Meanwhile, a heterogenous causal relationship between RA and mouth ulcers was observed (OR = 1.027 [1.005-1.05], p = 0.016, P heterogeneity = 4.69 × 10-8), which remained robust across sensitivity analyses. After excluding outlier variants, the results demonstrated robustly consistent (OR = 1.021 [1.008-1.035], p = 1.99 × 10-3, P heterogeneity = 0.044). However, upon adjusting for covariates such as smoking, alcohol consumption, body mass index, and obesity, the significance diminished, revealing no evidence to support independent genetic associations. Genetically predicted RA increases the risk of mouth ulcers, and a negative genetic correlation is identified between RA and denture use. The observed heterogeneity suggests that shared immunological mechanisms and environmental factors may play significant roles. These findings highlight the importance of targeted dental management strategies for RA patients. Further clinical guidelines are required to improve oral health among vulnerable RA patients.

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

BackgroundEvidence links major depressive disorder (MDD) with aging, but it's unclear if MDD accelerates aging and what factors mediate this transition. MethodsTwo-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. ResultsMDD 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. LimitationsConfounding, statistical power, and Euro-centric focus limit generalization. ConclusionOverall, 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.

Causal Relationships between Homocysteine and the Polycystic Ovary Syndrome: A Mendelian Randomization Analysis.

Polycystic ovary syndrome (PCOS) is an endocrine disease attributed to multiple genetic variants and environmental factors. We aimed to find the causal association of homocysteine (Hcy) with PCOS. A two-sample Mendelian randomization (MR) analysis was performed. We selected 14 single-nucleotide polymorphisms (SNPs) as instrumental variables to predict the risk of PCOS from genome-wide association studies (GWAS). The summary statistics of PCOS were obtained from 3 large genome-wide association studies in the European population, involving 4,138 cases and 20,129 controls, 3,609 cases and 229,788 controls, 994 cases and 165,817 controls, separately. The IVM analyses revealed that plasma Hcy levels were not causally associated with the risk of PCOS in the meta-analysis (combined effect = 1.032, 95% confidence interval (CI): 0.885-1.203, p=0.688). There was no sufficient evidence to support the causal association of the Hcy with the risk of PCOS.

Association between autoimmune liver diseases and chronic hepatitis B: A multivariable Mendelian randomization study in European population

BackgroundObservational studies have indicated a link between autoimmune liver diseases (AILD) and chronic hepatitis B (CHB) through observational studies. The association between AILD and CHB remains indeterminate. MethodsA two-sample Mendelian randomization (MR) analysis was conducted to scrutinize the causal nexus between AILD and CHB utilizing summary statistics derived from extensive genome-wide association studies (GWASs) in European populations. The primary statistical methodology employed was the inverse variance-weighted (IVW) method to deduce the causal connection of AILD on CHB. This study incorporated primary biliary cholangitis (PBC), primary sclerosing cholangitis (PSC), and autoimmune hepatitis (AIH) as subtypes of AILD. Additionally, we conducted a multivariable MR (MVMR) analysis to account for the potential confounding effects of smoking, alcohol consumption, body mass index (BMI), and some autoimmune diseases. ResultsOur MR investigation encompassed a cohort of 725,816 individuals. The MR analysis revealed that genetically predicted PSC significantly correlated with a reduced risk of CHB (IVW OR = 0.857; 95%CI: 0.770–0.953, P = 0.005). Conversely, the reverse MR analysis suggested that genetic susceptibility to PSC might not modify the risk of CHB (IVW OR = 1.004; 95% CI: 0.958–1.053, P = 0.866). Genetically proxied PBC and AIH exhibited no discernible causal association with CHB in the MR analysis using the IVW method (P = 0.583; P = 0.425). The MVMR analysis still indicated a decreased risk of CHB associated with PSC (OR = 0.853, P = 0.003). ConclusionOur study elucidates a causal relationship between PSC and a diminished risk of CHB.

Characterization of microsatellite markers in the coding regions of the Penaeus vannamei genome.

In this study, an extensive analysis of microsatellite markers (Single Tandem Repeats-STRs) in Penaeus vannamei was conducted at an advanced level. The markers were thoroughly examined, characterized, and specific markers located within coding regions were identified. Out of a total of 306 STRs, 117 were classified as perfect markers based on their single repeat motif. Among these perfect markers, 62 were found to be associated with predicted coding genes (mRNA), which were involved in various functions such as binding, catalytic activity, ATP-dependent activity, transcription, structural and molecular regulation. To validate the accuracy of the findings, a sample of nine markers was subjected to in vitro testing, which confirmed the presence of polymorphisms within the population. These results suggest the existence of different protein isoforms within the population, indicating the potential of these markers for application in both population and phenotype-genotype association studies. This innovative approach opens up new possibilities for investigating the impact of genomic plasticity in populations of P. vannamei.