Racial Differences in General Health, Suicidal Thoughts, Physical and Sexual Abuse in African-Americans and Caucasians with Irritable Bowel Syndrome:

Causality Between Irritable Bowel Syndrome and Suicide Attempt: A Mendelian Randomization Study

BACKGROUND

Prior research has indicated a correlation between irritable bowel syndrome (IBS) and suicidal behavior. Nevertheless, it remains uncertain if this correlation implies causation.

METHODS

We used univariate and multivariate Mendelian randomization. The United Kingdom Biobank provided 53,400 European patients and 433,201 European controls for the IBS GWAS. The outcome variable was developed from a genome-wide association analysis of 26,590 suicide attempt cases and 492,022 controls from the International Suicide Genetics Consortium. BioBank Finland GWAS data (9,771 cases and 402,410 controls) was used for SA validation. Primarily employing inverse variance weighting (IVW), we conducted the analysis to establish causality. MR-Egger and weighted median were used as complementary methods to reinforce the robustness and validity of the results. We used the MRlap method to eliminate the effect of sample overlap. We also used a multivariable MR approach to control for the influence of potential confounders. Using a number of approaches, including the Cochran's Q test, the MR-Egger intercept, and the MR-PRESSO methodology, the study examined pleiotropy and heterogeneity.

RESULTS

We discovered evidence for an elevated risk of suicide attempt with IBS (OR = 1.67, 95% CI = 1.21-2.35, P = 5.52E-07). MRlap analyses similarly support this result. We got the same results with the validation data (OR = 1.19, 95% CI = 1.06-1.34, P = 2.46E-03). The relationships between the different sensitivity analysis approaches were similar, and there was no indication that outliers influenced these correlations. The independent causal impact of IBS on suicide attempts was maintained after controlling for anxiety, depression, and abdominal pain. In reverse MR, we found no causal link between suicide attempt and IBS.

CONCLUSION

Our MR analysis indicates a causal relationship between IBS and suicide risk. Early detection and intervention in suicidal ideation in IBS patients reduces their suicide risk. More study is needed to understand the mechanisms that link IBS and suicidal behavior, which may alter or broaden therapy for specific individuals.

Mendelian randomization analysis reveals causal relationship between tonsillectomy and irritable bowel syndrome

Objective

This study used two sample Mendelian randomization (MR) method to evaluate the causal relationship between tonsillectomy and irritable bowel syndrome (IBS).

Methods

We selected tonsillectomy as the exposure factor and IBS as the outcome variable, using GWAS data from the IEU Open GWAS project. Instrumental variables (IVs) were SNPs strongly correlated and independent of tonsillectomy. MR-PRESSO was used for outlier removal. IVW was the primary MR analysis method, supplemented by MR-Egger regression, WM, WME, and simple mode. Cochran's Q tests assessed heterogeneity. MR-Egger intercept tested horizontal pleiotropy. Sensitivity analysis used a leave-one-out method.

Results

The IVW analysis indicated a positive association between genetically predicted tonsillectomy and IBS (OR = 1.682, 95% CI: 1.157-2.446, P = 0.006). Heterogeneity tests revealed the presence of heterogeneity at the SNPs (Cochran Q test, P = 3.13 × 10-5. The MR-Egger intercept test did not detect horizontal pleiotropy (egger_intercept = 0.000914, P = 0.789). Sensitivity analysis demonstrated the stability of the results. All F-statistics were greater than 10, indicating the absence of weak instrument bias.

Conclusion

Genetics predicts a positive causal relationship between tonsillectomy and IBS, suggesting that prevention of IBS in tonsillectomy patients should be enhanced.

Allergy-related diseases and recurrent abdominal pain during childhood - a birth cohort study

BACKGROUND

Allergy and immune dysregulation may have a role in the pathophysiology of recurrent abdominal pain of functional origin, but previous studies of allergy-related diseases and abdominal pain have contradictory results.

AIM

To examine the association between allergy-related diseases or sensitisation during childhood and abdominal pain at age 12 years.

METHODS

In this birth cohort study of 4089 children, parents answered questionnaires regarding asthma, allergic rhinitis, eczema and food hypersensitivity ('allergy-related diseases') at ages 0,1,2,4,8 and 12 years. Blood for analyses of allergen-specific IgE was sampled at 4 and 8 years. At 12 years, the children answered questions regarding abdominal pain. Children with coeliac disease or inflammatory bowel disease were excluded. Associations were examined using multivariable logistic regression.

RESULTS

Among 2610 children with complete follow-up, 9% (n = 237) reported abdominal pain at 12 years. All allergy-related diseases were associated with concurrent abdominal pain at 12 years and the risk increased with increasing number of allergy-related diseases (P for trend <0.001). Asthma at 1 and 2 years and food hypersensitivity at 8 years were significantly associated with abdominal pain at 12 years. There was an increased risk of abdominal pain at 12 years in children sensitised to food allergens at 4 or 8 years, but in stratified analyses, this was confined to children whose parents had not reported food hypersensitivity at time of sensitisation.

CONCLUSION

Allergy-related diseases as well as sensitisation to food allergens were associated with an elevated risk of abdominal pain, and the risk increased with the number of allergy-related diseases.

Post-traumatic Stress Disorder Is Associated With Irritable Bowel Syndrome in African Americans

Background/Aims

Psychosocial stressors likely play an important role in irritable bowel syndrome (IBS). The association between IBS and post-traumatic stress disorder (PTSD) in non-minorities has been described. Our aim was to investigate the potential association between IBS and PTSD in an urban African American population.

Methods

Our institution maintains a longitudinal population-based survey of African Americans (AA). The survey utilizes a complex, stratified sampling design. The study group consisted of adult AA meeting Rome III criteria for IBS of any subtype. The 4-item Primary Care PTSD screener was administered; score of ≥ 3 (range, 0–4) was considered positive for PTSD. Depression (Public Health Questionnaire-9 depression) and anxiety (generalized anxiety disorder-7) levels were measured using standardized scales. To assess quality of life, norm-based physical and mental component summary scores from the short-form 36 health survey version 2 were obtained. Descriptive and inferential statistics were calculated using Complex Sample Module of SPSS after weighting of the study sample.

Results

Four hundred nineteen subjects included corresponded to a weighted 21,264 (95% CI, 19,777–22,751) individuals. The prevalence of IBS in our sample of urban AA was 8.2%. In multivariate regression analysis, female gender, age > 40, higher educational attainment and divorce were independently associated with IBS. Those with IBS were considerably more likely to suffer from PTSD (OR, 4.54; 95% CI, 4.07–5.06). PTSD was independently associated with depression, anxiety, harmful drinking and substance abuse.

Conclusions

In AA, PTSD is independently associated with IBS. PTSD has a significantly negative impact on physical and mental self-assessment of quality of life. Evaluation of minorities presenting with functional gastrointestinal disorders should include screening for PTSD.