Causal associations between polyunsaturated fatty acids and kidney function: A bidirectional Mendelian randomization study

Causal association between major depressive disorder and venous thromboembolism: a bidirectional mendelian randomization study

Purpose

Major depressive disorder (MDD) and venous thromboembolism (VTE) may be linked in observational studies. However, the causal association remains ambiguous. Therefore, this study investigates the causal associations between them.

Methods

We performed a two-sample univariable and multivariable bidirectional Mendelian randomization (MR) analysis to evaluate the associations between MDD and VTE. The summary genetic associations of MDD statistics were obtained from the Psychiatric Genomics Consortium and UK Biobank. Information on VTE, deep vein thrombosis (DVT), and pulmonary embolism (PE) were obtained from the FinnGen Biobank. Inverse-variance weighting was used as the main analysis method. Other methods include weighted median, MR-Egger, Simple mode, and Weighted mode.

Results

Univariable MR analysis revealed no significant associations between MDD and VTE risk (odds ratio (OR): 0.936, 95% confidence interval (CI): 0.736-1.190, p = 0.590); however, after adjusting the potential relevant polymorphisms of body mass index and education, the multivariable MR analysis showed suggestive evidence of association between them (OR: 1.163, 95% CI: 1.004-1.346, p = 0.044). Univariable MR analysis also revealed significant associations between MDD and PE risk (OR: 1.310, 95% CI: 1.073-1.598, p = 0.008), but the association between them was no longer significant in MVMR analysis (p = 0.072). We found no significant causal effects between MDD and DVT risk in univariable or multivariable MR analyses. There was also no clear evidence showing the causal effects between VTE, PE, or DVT and MDD risk.

Conclusion

We provide suggestive genetic evidence to support the causal association between MDD and VTE risk. No causal associations were observed between VTE, PE, or DVT and MDD risk. Further validation of these associations and investigations of potential mechanisms are required.

Immunological Indicators of Recurrent Pregnancy Loss: A Mendelian Randomization Study

Recurrent pregnancy loss (RPL) is thought to be related to maternal-fetal immune tolerance disorders. Immune monitoring of RPL patients mainly involves two aspects: inflammatory factors and immune cells. However, most observational studies have reported controversial findings. This study aimed to confirm whether abnormal inflammatory factors and immune cells in peripheral blood may lead to RPL, and guide clinical immune monitoring. We demonstrated causality using two-sample Mendelian randomization. Sensitivity analysis, reverse Mendelian randomization and meta-analysis were used to enhance the effectiveness of the results. There was a causal relationship between the level of IL-12 (OR = 1.78, 95% CI = 1.25-2.55; P = 0.00149) and RPL for 41 inflammatory factors. We screened 5 groups of immune cell subtypes that were causally associated with RPL: switched memory B-cell absolute count (OR = 0.66, 95% CI = 0.49-0.87, P = 0.00406), IgD + CD24 + B-cell absolute count (OR = 0.69, 95% CI = 0.53-0.88, P = 0.00319), CD39 + resting CD4 regulatory T-cell %CD4 regulatory T-cell (OR = 0.86, 95% CI = 0.78-0.95, P = 0.00252), activated & resting CD4 regulatory T-cell %CD4 regulatory T-cell (OR = 0.89, 95% CI = 0.82-0.97, P = 0.00938) and CD45 RA + CD28-CD8 + T-cell %CD8 + T-cell (OR = 0.99, 95% CI = 0.98-1.00, P = 0.01231). In terms of inflammatory factors, a causal relationship between IL-12 and RPL in peripheral blood was confirmed. We also identified five immune cell phenotypes that play a protective role. This suggests that there may be protective B cells and CD8 + T-cell subsets in peripheral blood, and the protective effect of Tregs was proved again. Immune monitoring of peripheral blood in patients with RPL seems to be necessary and the foundation for precision medicine.

Association between polyunsaturated fatty acids and progression among patients with diabetic kidney disease

AIMS

Diabetic kidney disease (DKD) is the major complication of diabetes mellitus (DM) and one of the leading causes of end-stage renal disease. Early detection and treatment are contributing to delay the progression of DKD. Dietary management has potential benefits for DKD, especially the intake of polyunsaturated fatty acids (PUFAs). However, there is a lack of sufficient evidence, so we aimed to explore the association between PUFAs intake and DKD progression.

METHODS

In the National Heath and Nutrition Examination Survey (NHANES) between 2011-2018, a cross-sectional study was conducted among adults with T2DM. DKD was diagnosed with urine albumin to creatinine ratio (ACR) ≥ 30 mg/g or estimated glomerular filtration rate (eGFR) ＜60 ml/min/1.73 m2. Using Survey package of R to arrange the collected PUFAs intake data in order from small to large and divide them into four equal parts, which were expressed as Q1, Q2, Q3 and Q4 respectively. To investigate the association between PUFAs intake and DKD, a weighted univariate logistic regression analysis was performed and the odds ratio (OR) and 95% confidence interval (CI) were calculated for the association with DKD and PUFAs quartiles.

RESULTS

The study involved 3287 participants with T2DM, including 2043 non-DKD and 1244 DKD patients. The results showed that the intake of PUFAs was a protective factor for DKD (p = 0.022), and with the increase of the PUFAs, renal function improved in DKD patients, the adjusted mean of eGFR and Scr changing from 57 (41, 86) in Q1 to 71 (55, 101) ml/min in Q4 (p 0.001), 103 (73, 131) in Q1 to 90 (68, 117) in Q4 (p = 0.031), respectively.

CONCLUSION

Our study indicated that intake of more PUFAs may contribute to delay DKD progression, while different n-6/n-3 ratios need to be explored to protect the kidney.

Associations between gut microbiota and three prostate diseases: a bidirectional two-sample Mendelian randomization study

According to previous observational researches and clinical trials, the gut microbiota is related to prostate diseases. However, the potential association between gut microbiota and prostate disorders is still uncertain. We first identified groups of gut microbiota based on the phylum, class, order, family, and genus levels from consortium MiBioGen. And we acquired prostate diseases statistics from the FINNGEN study and PRACTICAL consortium. Next, two-sample Mendelian randomization was used to investigate the potential associations between three prevalent prostate disease and gut microbiota. In addition, we performed a reverse MR analysis and Benjamini-Hochberg (BH) test for further research. We investigated the connection between 196 gut microbiota and three prevalent prostate diseases. We identified 42 nominally significant associations and 2 robust causative links. Upon correction for multiple comparisons using the Benjamini-Hochberg procedure, our analysis revealed a positive correlation between the risk of prostatitis and the presence of the taxonomic order Gastranaerophilales. Conversely, the risk of prostate cancer exhibited an inverse correlation with the presence of the taxonomic class Alphaproteobacteria. Our study revealed the potential association between gut microbiota and prostate diseases. The results may be useful in providing new insights for further mechanistic and clinical studies of prostate diseases.

The Causality between Gut Microbiota and Hypertension and Hypertension-related Complications: A Bidirectional Two-Sample Mendelian Randomization Analysis

BACKGROUND

Recent studies have highlighted a connection between gut microbiota and hypertension, yet the precise nature of this relationship remains unclear.

OBJECTIVE

This research aims to analyze the causal link between gut microbiota and hypertension, along with associated complications, utilizing two-sample bidirectional Mendelian randomization (MR).

MATERIALS AND METHODS

Summary data from genome-wide association studies (GWAS) meta-analyses, including gut microbiota GWAS data from 24 cohorts, and the latest GWAS data for hypertension-related conditions were acquired. Employing various MR methods, including Inverse-variance weighted (IVW), MR-Egger, Weighted Median, Simple Mode, and Weighted Mode, we investigated the association between gut microbiota and hypertension-related conditions. Sensitivity analyses were conducted for result stability, and reverse MR analysis assessed the potential for reverse causality.

RESULTS

The Mendelian randomization analysis involving 199 microbial taxa and four phenotypes identified 46 microbial taxa with potential causal links to hypertension and its complications. Following Bonferroni correction, genus.Victivallis showed a robust causal relationship with hypertension (OR = 1.08, 95% CI = 1.04-1.12, P = 9.82e-5). This suggests an 8% increased risk of hypertension with each unit rise in genus.Victivallis abundance.

CONCLUSION

In conclusion, this study establishes a causal connection between gut microbiota and hypertension, along with common associated complications. The findings unveil potential targets and evidence for future hypertension and complication treatment through gut microbiota interventions, offering a novel avenue for therapeutic exploration.

Total body bone mineral density and various spinal disorders: a Mendelian randomization study

Introduction

Observational studies have yielded inconsistent findings regarding the correlation between bone mineral density (BMD) and various spinal disorders. To explore the relationship between total-body BMD and various spinal disorders further, we conducted a Mendelian randomization analysis to assess this association.

Methods

Two-sample bidirectional Mendelian randomization (MR) analysis was employed to investigate the association between total-body BMD and various spinal disorders. The inverse-variance weighted (IVW) method was used as the primary effect estimate, and additional methods, including weighted median, MR-Egger, simple mode, and weighted mode, were used to assess the reliability of the results. To examine the robustness of the data further, we conducted a sensitivity analysis using alternative bone-density databases, validating the outcome data.

Results

MR revealed a significant positive association between total-body BMD and the prevalence of spondylosis and spinal stenosis. When total-body BMD was considered as the exposure factor, the analysis demonstrated an increased risk of spinal stenosis (IVW odds ratio [OR] 1.23; 95% confidence interval [CI], 1.14-1.32; P < 0.001) and spondylosis (IVW: OR 1.24; 95%CI, 1.16-1.33; P < 0.001). Similarly, when focusing solely on heel BMD as the exposure factor, we found a positive correlation with the development of both spinal stenosis (IVW OR 1.13, 95%CI, 1.05-1.21; P < 0.001) and spondylosis (IVW OR 1.10, 95%CI, 1.03-1.18; P = 0.0048). However, no significant associations were found between total-body BMD and other spinal disorders, including spinal instability, spondylolisthesis/spondylolysis, and scoliosis (P > 0.05).

Conclusion

This study verified an association of total-body BMD with spinal stenosis and with spondylosis. Our results imply that when an increasing trend in BMD is detected during patient examinations and if the patient complains of numbness and pain, the potential occurrence of conditions such as spondylosis or spinal stenosis should be investigated and treated appropriately.

Mendelian Randomization Analysis Reveals Causal Effects of Polyunsaturated Fatty Acids on Subtypes of Diabetic Retinopathy Risk

Polyunsaturated fatty acids (PUFAs) affect several physiological processes, including visual acuity, but their relationship with diabetic retinopathy (DR) remains elusive. The aim of this study was to determine whether PUFAs have a causal effect on DR. PUFAs- (total and omega-3 [FAw3] and omega-6 [FAw6] fatty acids and their ratio) and DR-associated single nucleotide polymorphisms derived from genome-wide association studies; sample sizes were 114,999 for fatty acids and 216,666 for any DR (ADR), background DR (BDR), severe non-proliferative DR (SNPDR), and proliferative DR (PDR). We hypothesized that the intra-body levels of PUFAs have an impact on DR and conducted a two-sample Mendelian randomization (MR) study to assess the causality. Pleiotropy, heterogeneity, and sensitivity analyses were performed to verify result reliability. High levels of PUFAs were found to be associated with reduced risk of both ADR and PDR. Moreover, FAw3 was associated with a decreased risk of PDR, whereas FAw6 demonstrated an association with lowered risks of both BDR and PDR. Our findings provide genetic evidence, for the first time, for a causal relationship between PUFAs and reduced DR risk. Consequently, our comprehensive MR analysis strongly urges further investigation into the precise functions and long-term effects of PUFAs, FAw3, and FAw6 on DR.

Mendelian Randomization Analysis Reveals Causal Associations of Polyunsaturated Fatty Acids with Sepsis and Mortality Risk

INTRODUCTION

Despite numerous observational studies reporting a positive correlation between polyunsaturated fatty acids (PUFAs) and the risk of sepsis and mortality, the causation of such an association has yet to be firmly established. Thus, our study aimed to undertake the Mendelian randomization (MR) approach to scrutinize the potential causalities of PUFAs with sepsis and mortality risk.

METHODS

We conducted the MR investigation using genome-wide association study (GWAS) summary statistics of PUFAs [including omega-3 fatty acids (omega-3), omega-6 fatty acids (omega-6), the ratio of omega-6 to omega-3 fatty acids (omega-6:3), docosahexaenoic acid (DHA), linoleic acid (LA)], sepsis, and sepsis mortality. We utilized the GWAS summary data from the UK Biobank. To establish reliable causality, we employed the inverse-variance weighted (IVW) method as the primary analytical approach, together with four additional MR methods. In addition, we performed heterogeneity and horizontal pleiotropy assessments using Cochrane's Q test and MR-Egger intercept test, respectively. Finally, we performed a series of sensitivity analyses to enhance the precision and veracity of our findings.

RESULTS

The IVW method showed that genetically predicted omega-3 [odd ratio (OR) 0.914, 95% confidence interval (CI) 0.845-0.987, P = 0.023] and DHA (OR 0.893, 95% CI 0.815-0.979, P = 0.015) were suggestively linked to a decreased risk of sepsis. Furthermore, genetically predicted DHA (OR 0.819, 95% CI 0.681-0.986, P = 0.035) was suggestively associated with a reduced risk of sepsis-related death. Conversely, the omega-6:3 ratio (OR 1.177, 95% CI 1.011-1.371, P = 0.036) was suggestively linked to an increased risk of sepsis-induced mortality. On the basis of the MR-Egger intercept assessment, it appears that our MR examination was not influenced by any horizontal pleiotropy (all P > 0.05). Moreover, the reliability of the estimated causal association was confirmed by the sensitivity analyses.

CONCLUSION

Our study supported the casual effect between PUFAs and susceptibility to sepsis and sepsis-related death. Our findings underline the importance of specific PUFAs levels, particularly for individuals with a genetic susceptibility to sepsis. Further research is needed to confirm these findings and investigate the underlying mechanisms.