Non-alcoholic fatty liver is associated with increased risk of irritable bowel syndrome: a prospective cohort study

Ultra-Processed Food Consumption and Long-Term Risk of Irritable Bowel Syndrome: A Large-Scale Prospective Cohort Study

BACKGROUND & AIMS

The considerable disease burden of irritable bowel syndrome (IBS) has coincided with the increase of ultraprocessed food (UPF) consumption over the past few decades. However, epidemiologic evidence for an association is lacking. We aimed to examine the long-term risk of IBS associated with UPF consumption in a large-scale prospective cohort.

METHODS

Participants who completed 24-hour dietary recalls during 2009 to 2012 from the UK Biobank, and free of IBS, celiac disease, inflammatory bowel disease, and any cancer at baseline, were included (N = 178,711; 53.1% female). UPF consumption was defined according to the NOVA food classification system, expressed as a percentage of UPF content in the total diet intake (as grams per day). The primary outcome was incident IBS. A Cox proportional hazard model was performed to estimate associated risk.

RESULTS

The mean UPF consumption was 21.0% (SD, 11.0%) of the total diet. During a median of 11.3 years of follow-up, 2690 incident IBS cases were identified. An 8% higher risk of IBS (hazard ratio, 1.08; 95% CI, 1.04-1.12) was associated with every 10% increment of UPF consumption. Compared with the lowest quartile of UPF consumption, the highest quartile was associated with a significantly increased risk of incident IBS (hazard ratio, 1.19; 95% CI, 1.07-1.33; Ptrend < .001). Subgroup analyses by age, sex, body mass index, smoking, and alcohol drinking status also showed similar results, except for the never/previous drinking subgroup. Further sensitivity analyses confirmed the positive association with a higher UPF consumption.

CONCLUSIONS

Our findings provide evidence that a higher UPF consumption is associated with an increased risk of incident IBS, with a significant dose-response relationship.

Functional gastrointestinal disorders, mental health, genetic susceptibility, and incident chronic kidney disease

BACKGROUND

Whether functional gastrointestinal disorders (FGIDs) are associated with the long-term risk of chronic kidney disease (CKD) remains unclear. We aimed to investigate the prospective association of FGIDs with CKD and examine whether mental health mediated the association.

METHODS

About 416,258 participants without a prior CKD diagnosis enrolled in the UK Biobank between 2006 and 2010 were included. Participants with FGIDs (including irritable bowel syndrome [IBS], dyspepsia, and other functional intestinal disorders [FIDs; mainly composed of constipation]) were the exposure group, and non-FGID participants were the non-exposure group. The primary outcome was incident CKD, ascertained from hospital admission and death registry records. A Cox proportional hazard regression model was used to investigate the association between FGIDs and CKD, and the mediation analysis was performed to investigate the mediation proportions of mental health.

RESULTS

At baseline, 33,156 (8.0%) participants were diagnosed with FGIDs, including 21,060 (5.1%), 8262 (2.0%), and 6437 (1.6%) cases of IBS, dyspepsia, and other FIDs, respectively. During a mean follow-up period of 12.1 years, 11,001 (2.6%) participants developed CKD. FGIDs were significantly associated with a higher risk of incident CKD compared to the absence of FGIDs (hazard ratio [HR], 1.36; 95% confidence interval [CI], 1.28-1.44). Similar results were observed for IBS (HR, 1.27; 95% CI, 1.17-1.38), dyspepsia (HR, 1.30; 95% CI, 1.17-1.44), and other FIDs (HR, 1.60; 95% CI, 1.43-1.79). Mediation analyses suggested that the mental health score significantly mediated 9.05% of the association of FGIDs with incident CKD and 5.63-13.97% of the associations of FGID subtypes with CKD. Specifically, the positive associations of FGIDs and FGID subtypes with CKD were more pronounced in participants with a high genetic risk of CKD.

CONCLUSION

Participants with FGIDs had a higher risk of incident CKD, which was partly explained by mental health scores and was more pronounced in those with high genetic susceptibility to CKD.

Prevalence and Associated Risk Factors of Irritable Bowel Syndrome Among General Population: A Cross-Sectional Study in Qassim Region, Saudi Arabia

Background Irritable bowel syndrome (IBS) affects 10-20% of the global population, primarily manifesting as functional issues leading to abdominal discomfort. Key contributors like genetics, psychological factors, weakened immunity, and environmental pollutants play significant roles. Regional variations exist, with prevalence rates ranging from 7-10% in certain areas like South Asia and the Middle East to as high as 20% in many Western countries. Objective The objective of this study is to assess the prevalence of irritable bowel syndrome (IBS) and its related risk factors among the general populace of the Qassim region, Saudi Arabia, aiming to offer valuable insights for healthcare planning and intervention strategies. Methods A cross-sectional descriptive study was conducted, utilizing a validated self-administered questionnaire among residents of the Qassim region aged over 18 years. The questionnaire included demographic information about the participants and the validated Rome IV questionnaire for IBS in adults. Ethical approval for the study was obtained from the Qassim Research Ethics Committee, and data analysis was conducted using R script language version 4.3.3. A significance level of p < 0.05 was employed to interpret the results. Results Overall, significant associations were observed between IBS diagnosis and food allergy (AOR = 2.34, 99% CI: 1.27-4.29), family history of IBS (Adjusted Odd Ratio (AOR) = 7.03, 99% CI: 3.51-15.74), and abdominal pain lasting more than six months (AOR = 2.54, 99% CI: 1.49-4.33). Conclusion This study highlights a high IBS prevalence (21.4%) in Saudi Arabia's Qassim region. While no overall soda-IBS link was found, males showed a protective effect. Significant associations were noted between food allergy, family history, and abdominal pain with IBS diagnosis, especially among females. Further research on gender disparities and familial and abdominal pain roles in IBS management is warranted.

Exposure to per- and polyfluoroalkyl substance and metabolic syndrome: A nationally representative cross-sectional study from NHANES, 2003-2018

Per- and polyfluoroalkyl substances(PFAS) are widespread organic pollutants with endocrine-disrupting effects on human health, but the association of PFAS exposure with metabolic syndrome remains conflicting. National Health and Nutrition Examination Survey(NHANES) program was utilized to evaluate the association of individual PFAS exposure and metabolic disorders and further determined the joint effect of PFAS co-exposures. 13921 participants and five PFAS exposures(PFHxS, MPAH, PFDE, PFNA, and PFUA) were included for analysis. The association between individual PFAS and metabolic syndrome varied in the specific PFAS and the specific metabolic disorder examined. PFHxS was negatively associated with obesity(Q4; OR = 0.75; P < 0.001), but positively associated with hyperlipidemia (Q3; OR = 1.2; P = 0.013). PFUA was negatively associated with obesity (Q4; OR = 0.6; P < 0.001), hyperlipidemia (Q3; OR = 0.85; P = 0.03), and non-alcoholic fatty liver disease (NAFLD, Q4; OR = 0.64; P = 0.015), but positively associated with hyperglycemia(Q3; OR = 1.27; P = 0.004). Furthermore, PFAS co-exposures were negatively associated with obesity(OR = 0.63; P < 0.001) and NAFLD(OR = 0.85; P = 0.021), and positively associated with hyperlipidemia(OR = 1.05; P = 0.022), but not significantly associated with hyperglycemia or hypertension. Overall, there was a negative association between PFAS co-exposures and metabolic severity score(β = -0.15; P < 0.001). Subgroup analysis stratified by gender and obesity consistently showed the negative association of PFAS co-exposures with metabolic severity score, and the positive association with hyperlipidemia. However, subgroup analysis showed a negative association with NAFLD in females but not in males, and a negative association with hyperglycemia in the obesity group, but not in the non-obesity group. Collectively, our study showed a negative association of PFAS co-exposures with metabolic syndrome severity score, but did not support a consistent association between PFAS co-exposures and individual components of metabolic syndrome. Additionally, there were gender-specific as well as BMI-specific differences in these associations. Further studies are needed to rule out the reverse causality and clarify the relationship of PFAS co-exposures with the specific metabolic disorder.

Fatty liver index (FLI): more than a marker of hepatic steatosis

Fatty liver index (FLI) was developed as a simple and accurate marker of hepatic steatosis. FLI is derived from an algorithm based on body mass index, waist circumference, and levels of triglycerides and gamma-glutamyltransferase, and it is widely used in clinical and epidemiological studies as a screening tool for discriminating between healthy and nonalcoholic fatty liver disease (NAFLD) subjects. However, a systematic review of the literature regarding FLI revealed that this index has more extensive relationships with biochemical and physiological parameters. FLI is associated with key parameters of lipid, protein and carbohydrate metabolism, hormones, vitamins and markers of inflammation, or oxidative stress. FLI can be a predictor or risk factor for a number of metabolic and nonmetabolic diseases and mortality. FLI is also used as an indicator for determining the effects of health-related prevention interventions, medications, and toxic substances on humans. Although in most cases, the exact mechanisms underlying these associations have not been fully elucidated, they are most often assumed to be mediated by insulin resistance, inflammation, and oxidative stress. Thus, FLI may be a promising marker of metabolic health due to its multiple associations with parameters of physiological and pathological processes. In this context, the present review summarizes the data from currently available literature on the associations between FLI and biochemical variables and physiological functions. We believe that this review will be of interest to researchers working in this area and can provide new perspectives and directions for future studies on FLI.

Collinsella aerofaciens as a predictive marker of response to probiotic treatment in non-constipated irritable bowel syndrome

Probiotics are exploited for adjuvant treatment in IBS, but reliable guidance for selecting the appropriate probiotic to adopt for different forms of IBS is lacking. We aimed to identify markers for recognizing non-constipated (NC) IBS patients that may show significant clinical improvements upon treatment with the probiotic strain Lacticaseibacillus paracasei DG (LDG). To this purpose, we performed a post-hoc analysis of samples collected during a multicenter, double-blind, parallel-group, placebo-controlled trial in which NC-IBS patients were randomized to receive at least 24 billion CFU LDG or placebo capsules b.i.d. for 12 weeks. The primary clinical endpoint was the composite response based on improved abdominal pain and fecal type. The fecal microbiome and serum markers of intestinal (PV1 and zonulin), liver, and kidney functions were investigated. We found that responders (R) in the probiotic arm (25%) differed from non-responders (NR) based on the abundance of 18 bacterial taxa, including the families Coriobacteriaceae, Dorea spp. and Collinsella aerofaciens, which were overrepresented in R patients. These taxa also distinguished R (but not NR) patients from healthy controls. Probiotic intervention significantly reduced the abundance of these bacteria in R, but not in NR. Analogous results emerged for C. aerofaciens from the analysis of data from a previous trial on IBS with the same probiotic. Finally, C. aerofaciens was positively correlated with the plasmalemmal vesicle associated protein-1 (PV-1) and the markers of liver function. In conclusion, LDG is effective on NC-IBS patients with NC-IBS with a greater abundance of potential pathobionts. Among these, C. aerofaciens has emerged as a potential predictor of probiotic efficacy.

Non-alcoholic fatty liver disease and socioeconomic determinants in an Iranian cohort study

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is widespread worldwide. On the other hand, social inequality and socioeconomic status (SES) can affect all aspects of health. Therefore, this study aimed to investigate the relationship between SES indicators and NAFLD.

METHODS

This was a cross-sectional study using data from the registration phase of the Hoveyzeh Cohort Study, which included 10,009 individuals aged 35-70 years from May 2016 to August 2018. Fatty liver disease was determined based on Fatty Liver Index (FLI). The crude and adjusted odds ratios were calculated by logistic regression analysis to estimate associations between the fatty liver index and SES after controlling the potential confounders.

RESULTS

According to the FLI index, there were 2,006 people with fatty liver (28%) and 5,246 people without fatty liver (72%). Several 4496 people (62%) were women. The chi-square test showed significant relationships between the educational level and skill level (P < 0.001), the wealth index (P < 0.001), and Townsend Index (P < 0.001) with fatty liver index. In multivariable analysis, after adjustment for age, sex, physical activity, smoking, type of residence, calorie intake, dyslipidemia, skill level, and diabetes, the wealth index (p < 0.001) was positively associated with the fatty liver index. Besides, a reverse and significant association was seen between the Townsend index and the fatty liver index(p < 0.001). In contrast, no significant associations were seen between gender and educational level with the fatty liver index.

CONCLUSIONS

A more vulnerable SES is associated with NAFLD. Fatty liver index and socioeconomic indicators can be powerful monitoring tools to monitor health differences in diagnosing NAFLD.

Associations between irritable bowel syndrome and non-alcoholic fatty liver disease: A systematic review

BACKGROUND

Irritable bowel syndrome (IBS) is associated with obesity and metabolic syndrome. IBS and non-alcoholic fatty liver disease (NAFLD) are highly prevalent entities worldwide and may share similar mechanisms including gut dysbiosis, impaired intestinal mucosal barrier and immune system activation.

AIM

To systematically review their association according to the Preferred Reporting Items for Systemic Review and Meta-analyses guidelines.

METHODS

PubMed, EMBASE and Cochrane Database of Systematic Reviews were searched for relevant papers. Manual searches were also performed.

RESULTS

Six studies were included. Both IBS and NAFLD subjects had significantly more metabolic risk factors like hypertension, obesity, dyslipidaemia and diabetes. Our review showed that 23.2% to 29.4% of NAFLD patients had IBS. IBS was significantly higher in NAFLD patients compared with patients without NAFLD (23.2% vs 12.5%, P < 0.01). A higher proportion of IBS patients had NAFLD (65.8% to 74.0%). IBS patients were three times more likely to have NAFLD compared with non-IBS patients (P < 0.001). Two studies showed a significant correlation between the severity of IBS and NAFLD. The proportion of NAFLD subjects with IBS increased with NAFLD severity.

CONCLUSION

Further prospective studies are warranted to evaluate the relationship and shared pathways between IBS and NAFLD, potentially leading to the development of future therapeutics.

Bile Acids, Intestinal Barrier Dysfunction, and Related Diseases

The intestinal barrier is a precisely regulated semi-permeable physiological structure that absorbs nutrients and protects the internal environment from infiltration of pathological molecules and microorganisms. Bile acids are small molecules synthesized from cholesterol in the liver, secreted into the duodenum, and transformed to secondary or tertiary bile acids by the gut microbiota. Bile acids interact with bile acid receptors (BARs) or gut microbiota, which plays a key role in maintaining the homeostasis of the intestinal barrier. In this review, we summarize and discuss the recent studies on bile acid disorder associated with intestinal barrier dysfunction and related diseases. We focus on the roles of bile acids, BARs, and gut microbiota in triggering intestinal barrier dysfunction. Insights for the future prevention and treatment of intestinal barrier dysfunction and related diseases are provided.

The prevalence and burden of Rome IV bowel disorders of gut brain interaction in patients with non-alcoholic fatty liver disease: a cross-sectional study

Rome IV bowel disorders of gut brain interaction (DGBI) and non-alcoholic fatty liver disease (NAFLD) are highly prevalent entities with overlapping pathophysiology and risk factors. We aimed to evaluate the prevalence and burden of Rome IV irritable bowel syndrome (IBS) in patients with NAFLD. Patients diagnosed with NAFLD were recruited from a specialist liver clinic. All participants completed assessments to determine liver fibrosis severity, including liver stiffness measurement (LSM), completed the Rome IV diagnostic questionnaire for bowel disorders of gut brain interaction, the IBS symptom severity score (IBS-SSS), and the EQ-5D-5L to measure of quality-of-life (QoL). 142 patients with NAFLD (71 (50%) female, mean age 53.5 (SD ± 14.9), BMI 35.2 (SD ± 8.1) kg/M²) were recruited. 79 (55.6%) patients met criteria for a Rome IV bowel DGBI, including 50 patients (35.2%) who met the criteria for IBS (mean IBS-SSS 277.2 (SD ± 131.5)). There was no difference in liver fibrosis scores between those with and without Rome IV IBS (FIB-4 scores p = 0.14, LSM p = 0.68). Patients with NAFLD and Rome IV IBS had significantly worse QoL scores (EQ-VAS p = 0.005 and EQ-5D-5L index p = 0.0007), impairment of usual activities of daily living (p = 0.012) and were more likely to report anxiety or depression (p = 0.038). Rome IV bowel DGBI such as IBS are highly prevalent in patients with NAFLD attending liver clinics and are associated with impaired QoL and psychosocial distress.