RETRACTED: A Mendelian Randomization Analysis Investigates Causal Associations between Inflammatory Bowel Diseases and Variable Risk Factors

Abstract

The question of whether variable risk factors and various nutrients are causally related to inflammatory bowel diseases (IBDs) has remained unanswered so far. Thus, this study investigated whether genetically predicted risk factors and nutrients play a function in the occurrence of inflammatory bowel diseases, including ulcerative colitis (UC), non-infective colitis (NIC), and Crohn’s disease (CD), using Mendelian randomization (MR) analysis. Utilizing the data of genome-wide association studies (GWASs) with 37 exposure factors, we ran Mendelian randomization analyses based on up to 458,109 participants. Univariable and multivariable MR analyses were conducted to determine causal risk factors for IBD diseases. Genetic predisposition to smoking and appendectomy as well as vegetable and fruit intake, breastfeeding, n-3 PUFAs, n-6 PUFAs, vitamin D, total cholesterol, whole-body fat mass, and physical activity were related to the risk of UC (p < 0.05). The effect of lifestyle behaviors on UC was attenuated after correcting for appendectomy. Genetically driven smoking, alcohol consumption, appendectomy, tonsillectomy, blood calcium, tea intake, autoimmune diseases, type 2 diabetes, cesarean delivery, vitamin D deficiency, and antibiotic exposure increased the risk of CD (p < 0.05), while vegetable and fruit intake, breastfeeding, physical activity, blood zinc, and n-3 PUFAs decreased the risk of CD (p < 0.05). Appendectomy, antibiotics, physical activity, blood zinc, n-3 PUFAs, and vegetable fruit intake remained significant predictors in multivariable MR (p < 0.05). Besides smoking, breastfeeding, alcoholic drinks, vegetable and fruit intake, vitamin D, appendectomy, and n-3 PUFAs were associated with NIC (p < 0.05). Smoking, alcoholic drinks, vegetable and fruit intake, vitamin D, appendectomy, and n-3 PUFAs remained significant predictors in multivariable MR (p < 0.05). Our results provide new and comprehensive evidence demonstrating that there are approving causal effects of various risk factors on IBDs. These findings also supply some suggestions for the treatment and prevention of these diseases.

Causality between sleep traits and the risk of frailty: a Mendelian randomization study

“…The remaining SNPs were then used as instrument variables after these operations. Additionally, we evaluated each SNP’s statistical efficacy using the F-statistic (F = β 2 /se 2 ) ( 31 ) and removed any that had poor statistical efficacy in order to reduce mild instrumental bias ( F > 10). Also, we lowered the GWAS p -value cutoff to 5.00E−06 for sleep apnea syndrome to ensure an adequate number of SNPs for the MR analysis.…”

Causality of Helicobacter pylori infection on eosinophilic esophagitis and potential pathogenesis: a Mendelian randomization study

“…Initially, a univariable MR analysis was conducted to examine the causal effects of H. pylori infection on EoE. The primary analysis in our study involved the utilization of the inverse-variance weighted (IVW) method ( 27 , 28 ). In instances where heterogeneity was detected, assessed by Cochran’s Q test, we applied a random effects model ( 29 ).…”

Nutritional Status and Its Detection in Patients with Inflammatory Bowel Diseases

“…A significant inverse association between dietary and supplementary vitamin D and UC and a nonsignificant reduction in the risk of CD have been reported [11]. Saadh et al [18] used Mendelian randomization (MR) analysis to assess risk factors for IBDs. This study enrolled 458,109 participants.…”

“…The authors reported a lower BMI in IBD patients compared to controls (19.8 [13.7-27.5] kg/m 2 vs. 23 [17.9-27.2] kg/m 2 , p < 0.0001). The other anthropometric parameters were also lower in IBD patients compared to the control group, as follows: biceps: 0.3 mm [0.1-1.9] vs. 0.5 mm [0.2-1.0], p < 0.0001; triceps: 0.7 mm [0.2-2.9] vs. 1.2 mm [0.5-2.3], p < 0.0001; skinfold thickness: biceps skinfold (BSF), triceps skinfold (TSF), and mid-arm muscle circumference (MAMC): 25.9 mm [15][16][17][18][19][20][21][23][24][25][26][27][29][30][31][32][33][34][35][36][37] vs. 26.8 mm [24][25][26][27][29][30][31][32][33][34], p < 0.04. Moreover, lower BMI and MAMC scores accompanied by lower serum protein concentration were observed in patients with active disease compared to patients in remission despite comparable daily dietary intake between groups [76].…”