Investigation of the causal relationship between inflammatory bowel disease and type 2 diabetes mellitus: a Mendelian randomization study
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SUBMITTER: Tang L
PROVIDER: S-EPMC10904574 | biostudies-literature | 2024 Jan
REPOSITORIES: biostudies-literature
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Project description:BackgroundObservational studies have indicated associations between type 2 diabetes mellitus (T2DM) and both colorectal cancer (CRC) and inflammatory bowel disease (IBD). However, the underlying causality and biological mechanisms between these associations remains unclear.MethodsWe conducted a bidirectional Mendelian randomization (MR) analysis employing summary statistics from genome-wide association studies involving European individuals. The inverse variance weighting (IVW) method was the primary method used to assess causality. Additionally, we applied MR Egger, Weighted median, Simple mode, and Weighted mode to evaluate the robustness of the results. Outliers were identified and eliminated using the MR-PRESSO, while the MR-Egger intercept was used to assess the horizontal pleiotropic effects of single nucleotide polymorphisms (SNPs). The heterogeneity was evaluated using the Cochrane Q test, and sensitivity analysis was performed using leave-one-out method. The F statistic was calculated to evaluate weak instrumental variable bias. Finally, a pilot bioinformatics analysis was conducted to explore the underlying biological mechanisms between T2DM and IBD/UC.ResultsThe IVW results demonstrated that T2DM significantly reduced risks of IBD (OR=0.885, 95% CI: 0.818-0.958, P=0.002) and ulcerative colitis (UC) (OR=0.887, 95% CI: 0.812-0.968, P=0.007). Although the 95% CIs of MR Egger, Weighted median, Simple mode, and Weighted mode were broad, the majority of their estimates were consistent with the direction of IVW. Despite significant heterogeneity among SNPs, no horizontal pleiotropy was observed. The leave-one-out analysis showed that the causality remained consistent after each SNP was removed, underscoring the reliability of the results. Reverse MR analysis indicated that genetic susceptibility to both CRC and IBD had no significant effect on the relative risk of T2DM. Ten hub genes were identified, which mainly enriched in pathways including maturity onset diabetes of the young, thyroid cancer, gastric acid secretion, longevity regulating pathway, melanogenesis, and pancreatic secretion.ConclusionThe presence of T2DM does not increase the risk of CRC or IBD. Moreover, T2DM might reduce risk of IBD, including UC. Conversely, the occurrence of CRC or IBD does not influence the risk of T2DM. The association between T2DM and IBD/UC may be related to the changes in multiple metabolic pathways and CTLA-4-mediated immune response.
| S-EPMC10836595 | biostudies-literature
Project description:The causality between smoking and type 2 diabetes is unclear. We conducted a two-sample Mendelian randomization study to explore the causal relationship between smoking initiation and type 2 diabetes. Summary-level data for type 2 diabetes were obtained from a meta-analysis of 32 genome-wide association studies (DIAbetes Genetics Replication And Meta-analysis consortium), which included 898 130 individuals of European ancestry. Totally, 377 single-nucleotide polymorphisms associated with smoking initiation at genome wide significance threshold (p < 5 × 10-8) were identified from the hitherto largest genome-wide association study on smoking. The inverse-variance weighted, weighted median, MR-Egger regression, and MR-PRESSO approaches were used to analyze the data. Genetically predicted smoking initiation was associated with type 2 diabetes with an odds ratio of 1.28 (95% confidence interval, 1.20, 1.37; p = 2.35 × 10-12). Results were consistent across sensitivity analyses and there was no evidence of horizontal pleiotropy. This study provides genetic evidence supporting a causal association between the smoking initiation and type 2 diabetes. Reducing cigarette smoking initiation can now be even more strongly recommended for type 2 diabetes prevention.
| S-EPMC6920406 | biostudies-literature
Project description:ObjectiveThe aim of this study was to investigate the bidirectional causal relationship between sex hormones and IBD through a two-sample bidirectional Mendelian randomization (MR) study.MethodsBased on Genome-Wide Association Study (GWAS) pooled data on SHBG, total testosterone, bioavailable testosterone, estradiol, and IBD in a European population, we performed two-sample bidirectional MR analyses using single nucleotide polymorphisms (SNPs) as instrumental variables. We used inverse variance weighting (IVW), weighted median, weighted mode, and MR-Egger to assess bidirectional causality between sex hormones and IBD.ResultsThere was no causal relationship between sex hormones and IBD in women (P > 0.05), and there was a causal and positive correlation between SHBG and testosterone and IBD in men.The OR for SHBG was 1.22 (95% CI: 1.09-1.37, P = 0.0004), and for testosterone was 1.20 (95% CI: 1.04-1.39, P = 0.0145).IBD did not significantly interact with female sex hormones but resulted in a decrease in SHBG (OR = 1.02, 95% CI: 1.00-1.04, P = 0.0195) and testosterone (OR = 1.01, 95% CI: 1.00 -1.02, P = 0.0200) in men.ConclusionThere is no causal relationship between female sex hormones and IBD, but male SHBG and testosterone are positively correlated with the risk of IBD and IBD promotes elevated levels of SHBG and testosterone in males, suggesting that sex hormones play different roles in IBD patients of different sexes.
| S-EPMC11813775 | biostudies-literature
Project description: Not available
| S-EPMC10797250 | biostudies-literature
Project description:BackgroundAlthough several observational studies have attempted to investigate the association between type 2 diabetes mellitus (T2DM) and lung cancer risk, the results are controversial. Here, we intend to examine whether there is a causal association between T2DM and lung cancer risk.Materials and methodsWe conducted a Mendelian randomization (MR) study to systematically investigate the effect of T2DM on lung cancer among 13,327 cases and 13,328 controls. A weighted genetic risk score (wGRS) was constructed as a proxy instrument by using 82 previously reported T2DM-related single nucleotide polymorphisms (SNPs). The logistic regression model was utilized to estimate associations of T2DM-related SNPs and wGRS with lung cancer risk. Sensitivity analyses were also performed to assess the robustness of the observed associations.ResultsWe found no evidence for a causal relationship between T2DM and lung cancer risk (odds ratio, OR = 0.96, 95% confidence interval: 0.91-1.01, p = 0.96), and the association did not vary among populations of different age, sex, smoking status, and histological type. Sensitivity analyses (e.g., MR-Egger test) suggest that pleiotropic effects did not bias the result.ConclusionIn this MR study with a large number of lung cancer cases, we found no evidence to support the causal role of T2DM in lung cancer risk. Further large-scale prospective studies are warranted to replicate our findings.
| S-EPMC8439278 | biostudies-literature
Project description:The relationship between simple appendicitis and inflammatory bowel disease (IBD) is not clear. In this study, we approach the issue from a genetic perspective, using Mendelian randomization (MR) tools to explore the potential causal connection between the two. We used GWAS data from 12,882 IBD patients (21,770 controls), 5956 crohn's disease (CD) patients (14,927 controls), 6968 ulcerative colitis (UC) patients (20,464 controls), and 4604 simple appendicitis patients (481,880 controls). These statistical data were derived from a large-scale whole-genome association study of individuals with European ancestry. The primary analytical method for inferring the causal relationship between the conditions involved the use of the Inverse Variance Weighting (IVW) method as the main approach for bidirectional MR analysis. The MR analysis results predicted IBD was associated with a lower risk of simple appendicitis (OR: 0.947 (0.911, 0.984), p = 0.005). The results for CD (OR: 0.948 (0.916, 0.981), p = 0.002) and UC (OR: 0.954 (0.917, 0.992), p = 0.020) are consistent with this finding. In the reverse MR analysis, there is no significant association between simple appendicitis and the occurrence of IBD (p > 0.05), and the same holds true for CD and UC (p > 0.05). Our MR study results suggest a potential negative causal effect of IBD on the occurrence of simple appendicitis. Conversely, there does not appear to be a significant causal relationship between simple appendicitis and the risk of developing IBD.
| S-EPMC11464600 | biostudies-literature
Project description:The association between rosacea and inflammatory bowel disease (IBD) has been studied in previous observational studies. It is unclear, however, whether the association is causal or not. Independent genetic variants for IBD were chosen as instruments from published Genome-wide association studies (GWAS) studies involving 38,155 cases with an IBD diagnosis and 48,485 controls in order to investigate the causal effect of IBD on rosacea. Summarized data for rosacea were gathered from various GWAS studies that included 1195 cases and 211,139 controls without rosacea. Reverse-direction Mendelian randomization (MR) analysis was done to investigate the relationship between genetically proxied rosacea and IBD. With the use of the inverse variance-weighted (IVW), MR-Egger, and weighted median approaches, a 2-sample Mendelian randomization study was carried out. Analysis of heterogeneity and sensitivity was performed to examine the pleiotropy and robustness of effect estimates. The forward-direction of the MR study was to reveal that genetic predisposition to IBD including its two main subtypes: Crohn's disease (CD) and ulcerative colitis (UC) was associated with an increased risk of rosacea. The reverse-direction MR analyses did not demonstrate that a genetic predisposition to rosacea was associated with total IBD, UC and CD. Our findings provided evidence for a causal impact of IBD, UC, and CD on rosacea, but not vice versa. The elevated incidence of rosacea in patients with IBD should be recognized by doctors to make an early diagnosis and initiate specialized therapy.
| S-EPMC10492847 | biostudies-literature
Project description:PurposeType 1 diabetes mellitus (T1DM) is associated with different types of infections; however, studies on the causal relationship between T1DM and infectious diseases are lacking. Therefore, our study aimed to explore the causalities between T1DM and six high-frequency infections using a Mendelian randomization (MR) approach.MethodsTwo-sample MR studies were conducted to explore the causalities between T1DM and six high-frequency infections: sepsis, acute lower respiratory infections (ALRIs), intestinal infections (IIs), infections of the genitourinary tract (GUTIs) in pregnancy, infections of the skin and subcutaneous tissues (SSTIs), and urinary tract infections (UTIs). Data on summary statistics for T1DM and infections were obtained from the European Bioinformatics Institute database, the United Kingdom Biobank, FinnGen biobank, and Medical Research Council Integrative Epidemiology Unit. All data obtained for summary statistics were from European countries. The inverse-variance weighted (IVW) method was employed as the main analysis. Considering the multiple comparisons, statistical significance was set at p< 0.008. If univariate MR analyses found a significant causal association, multivariable MR (MVMR) analyses were performed to adjust body mass index (BMI) and glycated hemoglobin (HbA1c). MVMR-IVW was performed as the primary analysis, and the least absolute shrinkage and selection operator (LASSO) regression and MVMR-Robust were performed as complementary analyses.ResultsMR analysis showed that susceptibility to IIs increased in patients with T1DM by 6.09% using the IVW-fixed method [odds ratio (OR)=1.0609; 95% confidence interval (CI): 1.0281-1.0947, p=0.0002]. Results were still significant after multiple testing. Sensitivity analyses did not show any significant horizontal pleiotropy or heterogeneity. After adjusting for BMI and HbA1c, MVMR-IVW (OR=1.0942; 95% CI: 1.0666-1.1224, p<0.0001) showed significant outcomes that were consistent with those of LASSO regression and MVMR-Robust. However, no significant causal relationship was found between T1DM and sepsis susceptibility, ALRI susceptibility, GUTI susceptibility in pregnancy, SSTI susceptibility, and UTI susceptibility.ConclusionsOur MR analysis genetically predicted increased susceptibility to IIs in T1DM. However, no causality between T1DM and sepsis, ALRIs, GUTIs in pregnancy, SSTIs, or UTIs was found. Larger epidemiological and metagenomic studies are required to further investigate the observed associations between the susceptibility of certain infectious diseases with T1DM.
| S-EPMC10102543 | biostudies-literature
Project description:The causal relationship between inflammatory bowel disease (IBD) and diabetes mellitus remains unclear. The aim of this study was to delve into this association and investigate the correlation between AMP-activated protein kinase (AMPK), a target gene of metformin, and the risk of developing IBD. Researchers conducted a bidirectional two-sample Mendelian randomization analysis to examine causal relationships between IBD, including ulcerative colitis and Crohn disease (CD), and diabetes mellitus, encompassing both type 1 diabetes mellitus (T1DM) and type 2 diabetes mellitus (T2DM). Additionally, this study utilized AMPK-related variants associated with HbA1c (%) as instrumental variables for the metformin target gene AMPK to further investigate their association with the risk of IBD. The inverse variance weighted method was used as the primary analytical approach. Mendelian randomization analysis revealed a suggestive association between IBD and T1DM (P = .024). CD was associated with an increased risk of T1DM (P = .011). In the reverse analysis, T1DM also increased the risk of IBD (P = .043). No causal relationship was found between IBD and T2DM in either the forward or reverse analyses. In addition, this study did not find any significant effect of AMPK on IBD. In conclusion, this study suggests a bidirectional association between IBD and T1DM, in which CD may increase the risk of T1DM. However, no causal relationship was found between IBD and T2DM. Furthermore, our findings revealed that the metformin's target gene AMPK had no significant effect on the onset of IBD.
| S-EPMC11835072 | biostudies-literature
Project description:BackgroundObservational studies have indicated an association between diabetes mellitus (DM), glycemic traits, and the occurrence of Parkinson's disease (PD). However, the complex interactions between these factors and the presence of a causal relationship remain unclear. Therefore, we aim to systematically assess the causal relationship between diabetes, glycemic traits, and PD onset, risk, and progression.MethodWe used two-sample Mendelian randomization (MR) to investigate potential associations between diabetes, glycemic traits, and PD. We used summary statistics from genome-wide association studies (GWAS). In addition, we employed multivariable Mendelian randomization to evaluate the mediating effects of anti-diabetic medications on the relationship between diabetes, glycemic traits, and PD. To ensure the robustness of our findings, we performed a series of sensitivity analyses.ResultsIn our univariable Mendelian randomization (MR) analysis, we found evidence of a causal relationship between genetic susceptibility to type 1 diabetes (T1DM) and a reduced risk of PD (OR = 0.9708; 95% CI: 0.9466, 0.9956; P = 0.0214). In our multivariable MR analysis, after considering the conditions of anti-diabetic drug use, this correlation disappeared with adjustment for potential mediators, including anti-diabetic medications, insulin use, and metformin use.ConclusionOur MR study confirms a potential protective causal relationship between genetically predicted type 1 diabetes and reduced risk of PD, which may be mediated by factors related to anti-diabetic medications.
| S-EPMC10913216 | biostudies-literature