Genetic Predisposition of Anti-Cytomegalovirus Immunoglobulin G Levels and the Risk of 9 Cardiovascular Diseases

Mediating role of chiro-inositol metabolites on the effects of HLA-DR-expressing CD14 + monocytes in inflammatory bowel disease

BACKGROUND

Inflammatory bowel disease (IBD), a chronic inflammatory condition, is caused by several factors involving aberrant immune responses. Genetic factors are crucial in IBD occurrence. Mendelian randomization (MR) can offer a new perspective in understanding IBD's genetic background.

METHODS

Single nucleotide polymorphisms (SNPs) were considered instrumental variables (IVs). We analyzed the relationship between 731 immunophenotypes, 1,400 metabolite phenotypes, and IBD. The total effect was decomposed into indirect and direct effects, and the ratio of the indirect effect to the total effect was calculated.

RESULTS

We identified the causal effects of HLA-DR-expressing CD14 + monocytes on IBD through MR analysis. The phenotype "HLA-DR expression on CD14 + monocytes" showed the strongest association among the selected 48 immune phenotypes. Chiro-inositol metabolites mediated the effect of CD14 + monocytes expressing HLA-DR on IBD. An increase in Chiro-inositol metabolites was associated with a reduced risk of IBD occurrence, accounting for 4.97%.

CONCLUSION

Our findings revealed a new pathway by which HLA-DR-expressing CD14 + monocytes indirectly reduced the risk of IBD occurrence by increasing the levels of Chiro-inositol metabolites. The results provided a new perspective on the immunoregulatory mechanisms underlying IBD, laying a theoretical foundation for developing new therapeutic targets in the future.

Vascular Endothelial Growth Factor and Ischemic Stroke Risk: A Mendelian Randomization Study

INTRODUCTION

Previous studies have reported controversial relationships between circulating vascular endothelial growth factors (VEGF) and ischemic stroke (IS). This study aims to demonstrate the causal effect between VEGF and IS using Mendelian randomization (MR).

METHODS

Summary statistics data from two large-scale genome-wide association studies (GWAS) for 16,112 patients with measured VEGF levels and 40,585 patients with IS were downloaded from public databases and included in this study. A published calculator was adopted for MR power calculation. The primary outcome was any ischemic stroke, and the secondary outcomes were large-artery stroke, cardioembolic stroke, and small-vessel stroke. We used the inverse variance-weighted (IVW) method for primary analysis, supplemented by MR-Egger regression and the weighted median method.

RESULTS

Nine SNPs were included to represent serum VEGF levels. The IVW method revealed no strong causal association between VEGF and any ischemic stroke (odds ratio [OR] 1.01, 95% CI 0.99-1.04, p = 0.39), cardioembolic stroke (OR 1.04, 95% CI 0.97-1.12, p = 0.28), large-artery stroke (OR 1.02, 95% CI 0.95-1.09, p = 0.62), and small-vessel stroke (OR 0.98, 95% CI 0.91-1.04, p = 0.46). These findings remained robust in sensitivity analyses. MR-Egger regression suggested no horizontal pleiotropy.

CONCLUSIONS

This Mendelian randomization study found no relationship between genetically predisposed serum VEGF levels and risks of IS or its subtypes.

Management and Nursing Approaches to Low Back Pain: Investigating the Causal Association with Lifestyle-Related Risk Factors

BACKGROUND

Notwithstanding a plethora of observational studies, the causal implications of obesity, encompassing both body mass index (BMI) and waist circumference (WC), as well as type 2 diabetes (T2D), and lifestyle factors, in relation to the vulnerability to low back pain (LBP), remain enigmatic.

AIMS

This study was designed to investigate the related causal associations DESIGN: A two-sample Mendelian randomization (MR) analysis.

SETTINGS

By utilizing genetic variants associated with pertinent factors gleaned from genome-wide association studies (GWASs), We extracted independent genetic variants about exposures such as BMI, WC, T2D, smoking, alcohol consumption, and coffee intake from published GWASs, ensuring their genome-wide significance.

PARTICIPANTS/SUBJECTS

The GWASs were selected from the most up-to-date and largest publicly accessible databases.

METHODS

The summary data concerning LBP emanated from a GWAS of European cases and controls, which was based on the esteemed MRC-IEU (Medical Research Council Integrative Epidemiology Unit) consortium.

RESULTS

Heightened body mass index and waist circumference exhibited odds ratios of 1.003 (95% confidence interval [CI] = 1.002-1.004, p < 0.001) and 1.003 (95% CI = 1.002-1.004, p < 0.001) for LBP, respectively, per each standard deviation (SD) increase. As for smoking initiation and every SD increase in the frequency of alcohol intake, the odds ratios were 1.002 (95% CI = 1.001-1.003, p = 0.003) and 1.002 (95% CI = 1.000-1.003, p = 0.011), respectively, for LBP. Conversely, an increased log odds ratio for T2D, and prevalence of coffee intake, divulged no discernible causal effects on the risk of LBP.

CONCLUSION

This study provides suggestive evidence to support the causal involvement of obesity, smoking, and the frequency of alcohol intake in the development of LBP, which suggests that implementing measures to mitigate these risk factors may aid in preventing LBP.

Causations between obesity, diabetes, lifestyle factors and the risk of low back pain

BACKGROUND

Despite numerous observational studies, the causal relationship between obesity-measured by body mass index (BMI) and waist circumference (WC)-as well as type 2 diabetes (T2D), lifestyle habits, and susceptibility to low back pain (LBP) remains obscure.

METHODS

This investigation employed two-sample Mendelian randomization (MR) analysis to explore causality, using genetic variants linked to relevant factors from genome-wide association studies (GWASs). Specifically, we selected independent genetic variants related to BMI, WC, T2D, smoking, alcohol consumption, and coffee intake from established GWASs, all of which demonstrated genome-wide significance. The comparative data for LBP were derived from a GWAS involving European subjects, under the auspices of the renowned MRC-IEU (Medical Research Council Integrative Epidemiology Unit) consortium.

RESULTS

Elevated BMI and WC were associated with odds ratios of 1.002 (95% confidence interval [CI] = 1.001-1.004, p < 0.001) and 1.003 (95% CI = 1.002-1.004, p < 0.001) for LBP per standard deviation (SD) increase, respectively. Regarding smoking initiation and coffee consumption, the odds ratios stood at 1.002 (95% CI = 1.001-1.004, p = 0.001) and 1.004 (95% CI = 1.001-1.008, p = 0.034) for LBP, respectively. However, an augmented log odds ratio for T2D and each SD rise in alcohol consumption frequency revealed no significant causal impact on LBP risk.

CONCLUSION

Our findings indicate a potential causal link between obesity, smoking, and coffee intake in the genesis of LBP, suggesting that mitigating these factors could contribute to LBP prevention.

Exploring the association between COVID-19 and male genital cancer risk in European population: evidence from mendelian randomization analysis

BACKGROUND

Recently accumulated evidence indicates a potential association between COVID-19 and elevated susceptibility to cancer, including male genital cancer. However, the causal nature of this relationship remains unclear.

METHODS

In this Mendelian randomization (MR) study, we investigated the potential causal relationship between COVID-19 and male genital cancer using genetic variants as instrumental variables. We utilized summary statistics from two large-scale genome-wide association studies of COVID-19 hospitalized Vs. controls, as well as data from a population-based male genital cancer database based on European ancestry. We applied stringent quality control measures to select instrumental variables, including checking for linkage disequilibrium, removing low-quality variants, and assessing the strength of the instruments using the F-statistic. We conducted the MR  analysis using the inverse-variance weighted method and several sensitivity analyses (including MR Egger and Weighted Median MR analysis) to test the robustness of our results.

RESULTS

Our MR analysis revealed no causal associations between COVID-19 hospitalization and the incidence of male genital cancer. In the inverse-variance weighted analysis, no causal associations were observed between patients with COVID-19 hospitalization and the incidence of male genital cancer (odds ratio = 1.000 and 95% confidence interval = 0.998-1.001, p = 0.668). The estimated causal effect was consistent across all sensitivity analyses (including the Weighted Median, the MR Egger analysis, and the MR PROSSO analysis). The leave-one-out analysis showed that there was no any sing Single-nucleotide polymorphism significantly influencing our results.

CONCLUSIONS

Our study provides evidence that there is no causal association between COVID-19 hospitalization and male genital cancer.

Associations between adiposity, diabetes, lifestyle factors and the risk of gliomas

Background

Despite numerous observational studies linking adiposity, diabetes, and lifestyle factors with gliomas, the causal associations between them remain uncertain.

Methods

This study aimed to use two-sample Mendelian randomization (MR) analysis to investigate whether these associations are causal. Specifically, independent genetic variants in body mass index (BMI), waist circumference (WC), type 2 diabetes (T2D), smoking, alcohol, and coffee consumption were extracted from the published genome-wide association studies (GWASs) with genome-wide significance. The corresponding summary-level data for gliomas were available from a GWAS of 1,856 cases and 4,955 controls of European descent from the GliomaScan consortium. Additionally, glioma pathogenesis-related protein 1 data were used for validation, and Radial MR analysis was conducted to examine the potential outlier single-nucleotide polymorphisms (SNPs).

Results

One standard deviation (SD) increase in BMI had an odds ratio (OR) of 1.392 (95% confidence interval (CI), 0.935-2.071) for gliomas, while one SD increase in WC had an OR of 0.967 (95% CI, 0.547-1.710). For T2D, a one-unit increase in log-transformed OR had an OR of 0.923 (95% CI, 0.754-1.129). The prevalence of smoking initiation had an OR of 1.703 (95% CI, 0.871-3.326) for gliomas, while the prevalence of alcohol intake frequency had an OR of 0.806 (95% CI, 0.361-1.083), and the prevalence of coffee intake had an OR of 0.268 (95% CI, 0.033-2.140) for gliomas.

Conclusion

This study provides evidence that adiposity, T2D, smoking, alcohol drinking, and coffee intake do not play causal roles in the development of gliomas. The findings highlight the importance of reconsidering causal relationships in epidemiological research to better understand the risk factors and prevention strategies for gliomas.

An inverse causal association between genetically predicted vitamin D and chronic obstructive pulmonary disease risk

Aim

Observational studies have reported that levels of vitamin D were associated with the incidence of chronic obstructive pulmonary disease (COPD), but the relationship between them may have been confounded in previous studies. In this study, we aimed to determine the relationship between the levels of 25-hydroxyvitamin D (25OHD) and the risk of COPD by two-sample Mendelian randomization (MR) analysis.

Methods

Summary statistics for 25OHD and COPD in this study were obtained from the EBI (n = 496,946) consortium and Finn (n = 187,754) consortium. MR was adopted to explore the effect of the genetically predicted levels of 25OHD on the risk of COPD. Based on three assumptions of MR analysis, inverse variance weighting was used as the main analysis. To make our results more robust and reliable, MR Egger’s intercept test, Cochran’s Q test, funnel plot, and “leave-one-out” sensitivity analysis were used to assess the potential pleiotropy and heterogeneity in this study. Then, colocalization analysis and MR Steiger approaches were used to estimate the possible directions of estimates between them. Finally, we analyzed the causal associations between the four core genes (DHCR7, GC, CYP2R1, and CYP24A1) of vitamin D and the levels of 25OHD or the risk of COPD.

Results

Our results showed that each 1 standard deviation (SD) increase in the genetically predicted 25OHD level was associated with a 57.2% lower relative risk of COPD [odds ratio (OR): 0.428, 95% Cl: 0.279–0.657, p = 1.041 × 10−4], and the above association was also verified by maximum likelihood (OR: 0.427, 95% Cl: 0.277–0.657, p = 1.084 × 10−4), MR–Egger (OR: 0.271, 95% CI: 0.176–0.416, p = 2.466 × 10−4), MR-PRESSO (OR: 0.428, 95% Cl: 0.281–0.652, p = 1.421 × 10−4) and MR-RAPS (OR: 0.457, 95% Cl: 0.293–0.712, p = 5.450 × 10−4). Furthermore, colocalization analyses (rs3829251, PP.H4 = 0.99) and MR Steiger (“TRUE”) also showed a reverse association between them. Besides, the core genes of vitamin D also showed similar results except for CYP24A1.

Conclusion

Our findings provide evidence for a reverse association between genetically predicted 25OHD levels and COPD risk. Taking measures to supplement 25OHD may help reduce the incidence of COPD.

Genetically predicted obesity and risk of hip osteoarthritis

OBJECTIVES

To determine the causal association between genetically predicted obesity and the risk of hip osteoarthritis.

METHODS

We performed two-sample Mendelian randomization (MR) analysis to analyze the association between body mass index (BMI) and hip osteoarthritis using pooled-level genome-wide association study (GWAS) data. The inverse variance weighted (IVW), MR‒Egger, and weighted median methods were used to estimate the causal association. In addition, we applied the MR Steiger filtering method, MR robust adjusted profile score (MR.RAPS) methods, and the MR Pleiotropy RESidual Sum and Outlier (MR-PRESSO) global test to examine and address potential horizontal pleiotropy.

RESULTS

We found a causal relationship between genetically predicted BMI and the risk of hip osteoarthritis by the IVW method [OR = 1.45, 95% confidence interval (CI) = 1.04-2.00, P = 0.02]. In the sensitivity analysis, the results of the MR‒Egger and weighted median methods revealed similar estimations but with a wide CI with lower precision. The funnel plot, MR-Egger intercept, and MR-PRESSO all indicated the absence of a directional pleiotropic effect. In addition, no heterogeneity was observed in the present analysis. Therefore, the result of IVW is most suitable and reliable for the present MR analysis.

CONCLUSION

There is a causal relationship between obesity and a higher risk of hip osteoarthritis, suggesting that weight management may be an intervention for the prevention and management of hip osteoarthritis.

LEVEL OF EVIDENCE

Bioinformatics, Basic science.

Genetic Predisposition of Both Waist Circumference and Hip Circumference Increased the Risk of Venous Thromboembolism

BACKGROUND

 Obesity, especially abdominal obesity, is an independent indicator of increased cardiovascular risk. Observational studies have shown an observational association between obesity and venous thromboembolism (VTE). As a type of VTE, pulmonary embolism (PE) is also associated with obesity. However, it is unclear whether the observed associations are causal or caused by confounding bias or reverse causality.

METHODS

 We performed a two-sample test by obtaining the exposure dataset of waist circumference (WC) and hip circumference (HC) from the Neale Laboratory Consortium's genome-wide association study summary data and the summary-level outcome data of VTE and PE from FinnGen Biobank of European ancestry to determine the causal effect of WC and HC on VTE and PE.

RESULTS

 All three Mendelian randomization methods displayed a positive association between WC/HC and VTE/PE. WC and HC were positively associated with VTE (odds ratio [OR] = 1.803 per 1 standard deviation [SD] increase in WC, 95% confidence interval [CI] = 1.393-2.333; p < 0.001; OR = 1.479 per 1 SD increase in HC, 95% CI = 1.219-1.796; p < 0.001, respectively). Furthermore, we found a causal association between genetically predicted WC/HC and a higher risk of PE (OR = 1.929 per 1 SD increase in WC, 95% CI = 1.339-2.778, p < 0.001; OR = 1.431 per 1 SD increase in HC, 95% CI =1.095-1.869; p = 0.009, respectively).

CONCLUSION

 There is a significant causal relationship between WC/HC and VTE/PE, which is consistent with observational studies. Taking measures to reduce WC/HC of obesity may help reduce the incidence of VTE/PE.

No evidence of a genetic causal relationship between ankylosing spondylitis and iron homeostasis: A two-sample Mendelian randomization study

Background

Ankylosing spondylitis (AS) is an immune-mediated chronic inflammatory disease that leads to bone hyperplasia and spinal ankylosis. Iron homeostasis plays a very important role in the inflammatory response and is closely related to the pathogenesis of AS. This study aimed to use large-scale genome-wide association study (GWAS) summary data to study the genetic causal relationship between AS and iron homeostasis using Mendelian randomization (MR).

Methods

Genome-wide association study summary data of AS and iron homeostasis-related indicators were obtained from the FinnGen consortium and the DeCODE genetics database, respectively. We used four iron homeostasis-related indicators: ferritin, serum iron, total iron binding capacity (TIBC), and transferrin saturation (TSAT) for two-sample MR analyses to test for genetic causal association with AS using the "TwoSampleMR" package of the R software (version 4.1.2). The random-effects inverse variance weighted (IVW) method was the main analysis method used for MR. We examined the MR analysis results for heterogeneity, horizontal pleiotropy, and possible outliers. In addition, we confirmed the robustness of the MR analysis by testing whether the results were affected by a single SNP and whether they followed a normal distribution.

Results

The random-effects IVW results showed that ferritin [p = 0.225, OR 95% confidence interval (CI) = 0.836 (0.627-1.116)], serum iron [p = 0.714, OR 95% CI = 0.948 (0.714-1.260)], TIBC [p = 0.380, OR 95% CI = 0.917 (0.755-1.113)], and TSAT [p = 0.674, OR 95% CI = 0.942 (0.713-1.244)] have no genetic causal relationship with AS. We detected no heterogeneity，horizontal pleiotropy and possible outliers in our MR analysis (p > 0.05). In addition, our MR analysis results were not affected by a single SNP, and were normally distributed.

Conclusion

Our study did not detect a genetic causal relationship between AS and iron homeostasis. Nonetheless, this does not rule out a relationship between the two at other mechanistic levels.

Genetically predicted body fat mass and distribution with diabetic kidney disease: A two-sample Mendelian randomization study

The aim of this study is to apply a Mendelian randomization (MR) design to investigate the potential causal associations between the body mass index (BMI), body fat mass such as trunk fat mass and waist circumference (WC), and diabetic kidney disease (DKD). A two-sample MR study was conducted to obtain exposure and outcome data from previously published studies. The instrumental variables for BMI, trunk fat mass, and WC were selected from genome-wide association study datasets based on summary-level statistics. The random-effects inverse-variance weighted (IVW) method was used for the main analyses, and the weighted median and MR-Egger approaches were complementary. In total, three MR methods suggested that genetically predicted BMI, trunk fat mass, and WC were positively associated with DKD. Using IVW, we found evidence of causal relationships between BMI [odds ratio (OR) = 1.99; 95% confidence interval (CI), 1.47–2.69; p = 7.89 × 10−6], trunk fat mass (OR = 1.80; 95% CI, 1.28–2.53; p = 6.84 × 10−4), WC (OR = 2.48; 95% CI, 1.40–4.42; p = 1.93 × 10−3), and DKD. MR-Egger and weighted median regression also showed directionally similar estimates. Both funnel plots and MR-Egger intercepts showed no directional pleiotropic effects involving the aforementioned variables and DKD. Our MR analysis supported the causal effect of BMI, trunk fat mass, and WC on DKD. Individuals can substantially reduce DKD risk by reducing body fat mass and modifying their body fat distribution.

Causal Associations between Paternal Longevity and Risks of Cardiovascular Diseases

Background: Observational studies have suggested that paternal longevity is associated with reduced risks of cardiovascular diseases, yet the causal association remains to be determined. Objectives: To investigate whether Mendelian randomization (MR) results support a causal role of paternal longevity for risks of cardiovascular diseases. Methods: Genetic variants associated with paternal longevity and cardiovascular diseases were obtained from public genome-wide association study data. We used inverse variance weighted MR under a random-effects model to provide causal estimates between paternal longevity and cardiovascular diseases. Results: Paternal longevity was associated with decreased risks of coronary heart disease (odds ratio (OR): 0.08; 95% confidence interval (CI): 0.02–0.37; p = 0.001) and peripheral artery disease (OR: 0.15; 95% CI: 0.03–0.65; p = 0.011). No significant differences were observed in hypertension, atrial fibrillation, heart failure, transient ischemic attack, ischemic stroke, or cardiac death. The weighted median method revealed consistent results between genetically instrumented paternal longevity and decreased risk of coronary heart disease and peripheral artery disease. No significant differences were observed in the MR-Egger results. Multivariable MR consistently indicated causal associations between paternal longevity and decreased cardiovascular diseases. The leave-one-out analysis suggested that the causal associations were not affected by individual single-nucleotide polymorphisms. The intercept of the MR-Egger estimator and funnel plot revealed no indication of horizontal pleiotropic effects. Conclusions: Our MR analyses supported a causal role of paternal longevity for decreased risks of coronary heart disease and peripheral artery disease, which highlighted the need for better monitoring and intervention of cardiovascular diseases in populations with premature paternal death.

Genetically predicted C-reactive protein mediates the association between rheumatoid arthritis and atlantoaxial subluxation

OBJECTIVE

Investigating the causal relationship between rheumatoid arthritis (RA) and atlantoaxial subluxation (AAS) and identifying and quantifying the role of C-reactive protein (CRP) as a potential mediator.

METHODS

Using summary-level data from a genome-wide association study (GWAS), a two-sample Mendelian randomization (MR) analysis of genetically predicted rheumatoid arthritis (14,361 cases, and 43,923 controls) and AAS (141 cases, 227,388 controls) was performed. Furthermore, we used two-step MR to quantitate the proportion of the effect of c-reactive protein-mediated RA on AAS.

RESULTS

MR analysis identified higher genetically predicted rheumatoid arthritis (primary MR analysis odds ratio (OR) 0.61/SD increase, 95% confidence interval (CI) 1.36-1.90) increased risk of AAS. There was no strong evidence that genetically predicted AAS had an effect on rheumatoid arthritis risk (OR 1.001, 95% CI 0.97-1.03). The proportion of genetically predicted rheumatoid arthritis mediated by C-reactive protein was 3.7% (95%CI 0.1%-7.3%).

CONCLUSION

In conclusion, our study identified a causal relationship between RA and AAS, with a small proportion of the effect mediated by CRP, but a majority of the effect of RA on AAS remains unclear. Further research is needed on additional risk factors as potential mediators. In clinical practice, lesions of the upper cervical spine in RA patients need to be given more attention.