Greater Adherence to Cardioprotective Diet Can Reduce Inflammatory Bowel Disease Risk: A Longitudinal Cohort Study

Role of diet in prevention versus treatment of Crohn's disease and ulcerative colitis

Diet is a modifiable risk factor for disease course and data over the past decade have emerged to indicate its role in Crohn's disease (CD) and ulcerative colitis (UC). However, literature is riddled with misinterpretation of data, often leading to unexpected or conflicting results. The key understanding is that causative factors in disease development do not always proceed to an opportunity to change disease course, once established. Here, we discuss the data on dietary influences in three distinct disease states for CD and UC-predisease, active disease and quiescent disease. We appraise the literature for how our dietary recommendations should be shaped to prevent disease development and if or how that differs for CD and UC induction therapy and maintenance therapy. In UC, principles of healthy eating are likely to play a role in all states of disease. Conversely, data linking dietary factors to CD prevention and treatment are paradoxical with the highest quality evidence for CD treatment being exclusive enteral nutrition, a lactose, gluten and fibre-free diet comprising solely of ultraprocessed food-all dietary factors that are not associated or inversely associated with CD prevention. High-quality evidence from dietary trials is much awaited to expand our understanding and ultimately lead our dietary recommendations for targeted patient populations.

Risk Assessment for Gastrointestinal Diseases via Clinical Dimension and Genome-Wide Polygenic Risk Scores of Type 2 Diabetes: A Population-Based Cohort Study

OBJECTIVE

We aimed to evaluate whether individuals with type 2 diabetes (T2D) were at higher risk of developing a wide range of gastrointestinal diseases based on a population-based cohort study.

RESEARCH DESIGN AND METHODS

This study included 374,125 participants free of gastrointestinal disorders at baseline; of them, 19,719 (5.27%) with T2D were followed-up by linking to multiple medical records to record gastrointestinal disease diagnoses. Multivariable Cox models were used to estimate the hazard ratios (HRs) and CIs. Logistic models were used to examine the associations between polygenic risk scores (PRS) and clinical gastrointestinal phenotypes.

RESULTS

During a median follow-up of 12.0 years, we observed the new onset of 15 gastrointestinal diseases. Compared with nondiabetes, participants with T2D had an increased risk of gastritis and duodenitis (HR 1.58, 95% CI 1.51-1.65), peptic ulcer (HR 1.56, 95% CI 1.43-1.71), diverticular disease (HR 1.19, 95% CI 1.14-1.24), pancreatitis (HR 1.45, 95% CI 1.24-1.71), nonalcoholic fatty liver disease (HR 2.46, 95% CI 2.25-2.69), liver cirrhosis (HR 2.92, 95% CI 2.58-3.30), biliary disease (HR 1.18, 95% CI 1.10-1.26), gastrointestinal tract cancers (HR 1.28, 95% CI 1.17-1.40), and hepatobiliary and pancreatic cancer (HR 2.32, 95% CI 2.01-2.67). Positive associations of PRS of T2D with gastritis, duodenitis, and nonalcoholic fatty liver disease were also observed.

CONCLUSIONS

In this large cohort study, we found that T2D was associated with increased risks of a wide range of gastrointestinal outcomes. We suggest the importance of early detection and prevention of gastrointestinal disorders among patients with T2D.

Associations of Diet with Health Outcomes in the UK Biobank: A Systematic Review

The UK Biobank is a cohort study that collects data on diet, lifestyle, biomarkers, and health to examine diet-disease associations. Based on the UK Biobank, we reviewed 36 studies on diet and three health conditions: type 2 diabetes (T2DM), cardiovascular disease (CVD), and cancer. Most studies used one-time dietary data instead of repeated 24 h recalls, which may lead to measurement errors and bias in estimating diet-disease associations. We also found that most studies focused on single food groups or macronutrients, while few studies adopted a dietary pattern approach. Several studies consistently showed that eating more red and processed meat led to a higher risk of lung and colorectal cancer. The results suggest that high adherence to "healthy" dietary patterns (consuming various food types, with at least three servings/day of whole grain, fruits, and vegetables, and meat and processed meat less than twice a week) slightly lowers the risk of T2DM, CVD, and colorectal cancer. Future research should use multi-omics data and machine learning models to account for the complexity and interactions of dietary components and their effects on disease risk.

Dietary Patterns and Risk of Inflammatory Bowel Disease: A Systematic Review of Observational Studies

BACKGROUND

The incidence of inflammatory bowel disease (IBD) is increasing worldwide. Dietary patterns may be associated with odds of this disease. Although previous reviews have attempted to summarize the evidence in this field, the growing body of investigations prompted us to conduct an updated comprehensive systematic review.

METHODS

We used the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines to evaluate the association between dietary patterns before disease onset and the risk of IBD. PubMed, SCOPUS, and Web of Science were searched using structured keywords up to November 20, 2023.

RESULTS

Twenty-four publications (13 case-control, 1 nested case-control, and 10 cohort studies) were included in this review. The sample size of these studies ranged from 181 to 482 887 subjects. The findings were inconsistent across the included studies, showing inverse, direct, or no association between different dietary patterns and the risk of IBD.

CONCLUSIONS

This review provides comprehensive data on the link between dietary patterns prior to IBD diagnosis and risk of this condition. The explicit finding of present review is the extent gap in our knowledge in this field. Therefore, large-scale, high-quality studies are warranted to improve our understanding of the relationship between dietary patterns and IBD risk.

Adiposity as a risk factor for inflammatory bowel disease and the mediating effect of metabolic and inflammatory status: A population-based cohort study

BACKGROUND

To examine whether general and abdominal adiposity was a risk factor for the new-onset of inflammatory bowel disease (IBD) and the potential mediating effect of metabolic and inflammation status.

METHODS

A total of 492,998 individuals free of IBD recruited from 2006 to 2010 in the UK Biobank were included in our study, with ongoing follow-up linking to the health-related outcome. Multivariable Cox regression models were used to evaluate the associations between general adiposity (body mass index) and abdominal adiposity (waist circumference) and the subsequent risk of IBD and its subtype. We also investigated the potential mediating effects of metabolic and inflammation status by carrying out exploratory mediation analyses.

RESULTS

During a median follow-up of 12.5 years, we documented 2954 incident IBD cases (915 Crohn's disease [CD] and 2039 ulcerative colitis). After adjustment for important confounders, body mass index (hazard ratio [HR] highest quintile [Q5] vs. lowest quintile [Q1] = 1.18, 95% confidence interval [CI] 1.04-1.32; P-trend = 0.006) and waist circumference (HR Q5 vs. Q1  = 1.30, 95% CI 1.14-1.49; P-trend <0.001) showed a positive association with the risk of IBD. The associations were partially mediated by metabolic status (24%; 15%), C-reactive protein (36%; 19%) and inflammation score (82%; 46%).

CONCLUSIONS

Adiposity bore a risk factor for incident IBD, whereas unhealthy metabolism, especially inflammation, seemed to be an important intermediate condition between the association. Our findings provide evidence for possible mechanisms relating adiposity to IBD from an epidemiological perspective, and experimental studies are needed for further demonstration.

Higher Fiber Intake is Associated with Reduced Risk of Related Surgery among Individuals with Inflammatory Bowel Disease in a Prospective Cohort Study

BACKGROUND

Evidence for the effects of dietary fiber on adverse outcomes in individuals with inflammatory bowel disease (IBD) is insufficient and controversial.

OBJECTIVES

We aimed to prospectively explore the association between dietary fiber intake and the risk of IBD-related surgery.

METHODS

We identified 5580 individuals with diagnosed IBD [Crohn disease (CD, n = 1908) and ulcerative colitis (UC, n = 3672)] at baseline in the UK Biobank via electronic medical records and self-reported information. Dietary fiber intake was estimated by a partial fiber score derived from a valid food frequency questionnaire. IBD-related surgery (enterotomy, perianal surgery, and others) was ascertained via inpatient data. Cox proportional model was applied to estimate hazard ratios with 95% confidence intervals (CIs) of dietary fiber in quartiles for the risk of IBD-related surgery.

RESULTS

During a mean follow-up period of 11.2 y, we documented 624 IBD-related surgery among 5580 individuals with IBD (mean age, 57.3; 52.8% females). Compared with individuals in the lowest quartiles, those with second to fourth quartiles of fiber intake were associated with 23% (95% CI: 5%, 38%, P = 0.015), 29% (95% CI: 11%, 43%, P = 0.003), and 28% (95% CI: 10%, 43%, P = 0.005) reduced risk (P-trend = 0.002) of IBD-related surgery. Similar associations were observed in CD (P-trend = 0.005) but not UC (P-trend = 0.131). We observed inverse associations of fiber in vegetables and fruits (P-trend = 0.017 and 0.007) but positive associations of fiber in bread (P-trend = 0.046) with the risk of IBD-related surgery.

CONCLUSIONS

Higher intake of fiber is associated with reduced IBD-related surgery risk in patients with IBD with CD but not UC.

Higher Adherence to Cardioprotective Diet is Associated with Reduced Risk of Enterotomy and All-Cause Mortality among 5549 Individuals with Inflammatory Bowel Disease in a Prospective Cohort Study

BACKGROUND

The cardioprotective diet has been previously reported to be inversely associated with the development of inflammatory bowel disease (IBD), but whether it is beneficial to improve adverse outcomes in IBD remains unknown.

OBJECTIVES

We aimed to investigate whether the cardioprotective diet is associated with enterotomy and all-cause mortality among individuals with IBD.

METHODS

We conducted a prospective cohort study of 5549 participants with IBD from the UK Biobank. Cardioprotective diet scores (range 0-7) were calculated based on the consumption of 7 common food groups collected by a validated food frequency questionnaire. Outcomes of interest were enterotomy and all-cause mortality, ascertained via inpatient data and death registry, respectively. Cox proportional hazard models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs).

RESULTS

During an average follow-up duration of 12.0 y, we documented 506 enterotomy and 566 death events. Compared with participants with the lowest adherence to the cardioprotective diet (score of 0-2), participants with the highest adherence to the cardioprotective diet (score of 5-7) were observed to have a lower risk of enterotomy (HR: 0.60; 95% CI: 0.47, 0.76; P < 0.001; P-trend < 0.001) and all-cause mortality (HR: 0.77; 95% CI: 0.61, 0.98; P = 0.031; P-trend = 0.025).

CONCLUSIONS

A greater adherence to the cardioprotective diet is associated with a lower risk of enterotomy and all-cause mortality among individuals with IBD.

Ambient Air Pollution and Risk of Enterotomy, Gastrointestinal Cancer, and All-Cause Mortality among 4,708 Individuals with Inflammatory Bowel Disease: A Prospective Cohort Study

BACKGROUND

Previous studies indicated that air pollution plausibly increases the risk of adverse outcomes in inflammatory bowel disease (IBD) via proinflammatory mechanisms. However, there is scant epidemiological data and insufficient prospective evidence assessing associations between ambient air pollution and clinical outcomes of IBD.

OBJECTIVES

We aimed to investigate the associations between ambient air pollution and clinical outcomes among individuals with IBD.

METHODS

Leveraging data from the UK Biobank, we included 4,708 individuals with IBD recruited in the period 2006-2010 in this study. A land use regression model was used to assess annual mean concentrations of ambient air pollutants nitrogen including oxides (NO x ), nitrogen dioxide (NO 2 ), and particulate matter (PM) with aerodynamic diameter ≤ 10 μ m (PM 10 ) and PM with aerodynamic diameter ≤ 2.5 μ m (PM 2.5 ). Individuals with IBD were followed up for incident clinical outcomes of enterotomy, gastrointestinal cancer, and all-cause mortality, ascertained via death registry, inpatient, primary care, and cancer registry data. Cox proportional hazard model was used to estimate hazard ratios (HRs) with 95% confidence intervals (CIs) for the magnitude of the associations.

RESULTS

During a mean follow-up of 12.0 y, 265 enterotomy events, 124 incident gastrointestinal cancer, and 420 death events were documented among individuals with IBD. We found that each interquartile range (IQR) increase in exposure to PM 2.5 was associated with increased risk of enterotomy (HR = 1.16 ; 95% CI: 1.00, 1.34, p = 0.043 ), whereas an IQR increase in exposure to NO x (HR = 1.10 ; 95% CI: 1.01, 1.20, p = 0.016 ), NO 2 (HR = 1.16 ; 95% CI: 1.03, 1.29, p = 0.010 ), PM 10 (HR = 1.15 ; 95% CI: 1.03, 1.30, p = 0.015 ), and PM 2.5 (HR = 1.14 ; 95% CI: 1.02, 1.28, p = 0.019 ) was associated with increased risk of all-cause mortality among individuals with IBD. We did not observe any significant associations between air pollutants and gastrointestinal cancer in the primary analyses. Consistent results were observed in subgroup and sensitivity analyses.

CONCLUSIONS

Ambient pollution exposure was associated with an increased risk of enterotomy and all-cause mortality among individuals with IBD, highlighting the important role of environmental health in improving the prognosis of IBD. https://doi.org/10.1289/EHP12215.