Beyond the Gut: The Epidemiology of Extraintestinal Manifestations in Inflammatory Bowel Disease.

Inflammatory bowel diseases (Crohn's disease, ulcerative colitis) are chronic immune-mediated diseases of the gastrointestinal tract that are associated with many extraintestinal manifestations (EIMs). EIMs can affect nearly any organ system and are associated with impaired quality of life. This issue of The Clinical and Translational Gastroenterology includes a cross-sectional study of EIMs within the GETAID cohort, one of the largest to date reporting on the prevalence, risk factors, and predictors of remission for EIMs. We discuss how these results fit with existing literature and how clinicians may incorporate these insights into practice.

Periodontal disease is not associated with risk of inflammatory bowel disease: Results from two prospective cohort studies in the US.

AIM: To examine the relationship between periodontal disease and tooth loss and risk of inflammatory bowel disease (IBD). METHODS: We conducted a prospective cohort study of 86,602 women from the Nurses' Health Study (1992-2016) and 50,349 men from the Health Professionals Follow-up Study (1986-2016) with available data on periodontal disease and tooth loss. Cases of IBD were initially reported by participants and then confirmed by medical record review. We used Cox proportional hazards modelling to estimate multivariable-adjusted hazard ratios (aHRs) and 95% CIs. RESULTS: Through the end of follow-up, we documented 175 cases of Crohn's disease (CD) and 209 cases of ulcerative colitis (UC). After adjustment for potential risk factors, there was no association between periodontal disease and risk of CD (pooled aHR: 0.99, 95% CI: 0.65-1.52, p = 0.970) or UC (aHR: 0.99, 95% CI: 0.68-1.45, p = 0.971). Similarly, we did not observe an association between tooth loss and risk of CD (aHR: 0.72, 95% CI: 0.43-1.21, p = 0.218) or UC (aHR: 0.89, 95% CI: 0.58-1.36, p = 0.581) in the pooled analysis. The associations were not modified by sex, age, body mass index (BMI), smoking status or NSAID use (all pinteraction > 0.87). CONCLUSION: In two large prospective cohort studies, we did not observe an association between periodontal disease and tooth loss and risk of CD or UC.

Response to Severe Acute Respiratory Syndrome Coronavirus 2 Initial Series and Additional Dose Vaccine in Patients With Predominant Antibody Deficiency.

BACKGROUND: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in patients with predominant antibody deficiency (PAD) is associated with high morbidity, yet data regarding the response to SARS-CoV-2 immunization in PAD patients, including additional dose vaccine, are limited. OBJECTIVE: To characterize antibody response to SARS-CoV-2 vaccine in PAD patients and define correlates of vaccine response. METHODS: We assessed the levels and function of anti-SARS-CoV-2 antibodies in 62 PAD patients compared with matched healthy controls at baseline, at 4 to 6 weeks after the initial series of immunization (a single dose of Ad26.COV2.S [Janssen] or two doses of BNT162b2 [Pfizer-BioNTech] or mRNA-1273 [Moderna]), and at 4 to 6 weeks after an additional dose immunization, if received. RESULTS: After the initial series of SARS-CoV-2 vaccination, PAD patients had lower mean anti-spike antibody levels compared with matched healthy controls (140.1 vs 547.3 U/mL; P = .02). Patients with secondary PAD (eg, B-cell depletion therapy was used) and those with severe primary PAD (eg, common variable immunodeficiency with autoinflammatory complications) had the lowest mean anti-spike antibody levels. Immune correlates of a low anti-spike antibody response included low CD4+ T helper cells, low CD19+ total B cells, and low class-switched memory (CD27+IgD/M-) B cells. In addition, a low (<100 U/mL) anti-spike antibody response was associated with prior exposure to B-cell depletion therapy, both at any time in the past (odds ratio = 5.5; confidence interval, 1.5-20.4; P = .01) and proximal to vaccination (odds ratio = 36.4; confidence interval, 1.7-791.9; P = .02). Additional dose immunization with an mRNA vaccine in a subset of 31 PAD patients increased mean anti-spike antibody levels (76.3 U/mL before to 1065 U/mL after the additional dose; P < .0001). CONCLUSIONS: Patients with secondary and severe primary PAD, characterized by low T helper cells, low B cells, and/or low class-switched memory B cells, were at risk for low antibody response to SARS-CoV-2 immunization, which improved after an additional dose vaccination in most patients.

Lifestyle, behaviour, and environmental modification for the management of patients with inflammatory bowel diseases: an International Organization for Study of Inflammatory Bowel Diseases consensus.

Environmental and lifestyle factors play an important role in the natural history of Crohn's disease and ulcerative colitis. A group of international experts from the International Organization for the Study of Inflammatory Bowel Diseases voted on a series of consensus statements to inform the management of inflammatory bowel disease (IBD). The recommendations include avoiding traditional cigarette smoking in patients with Crohn's disease or ulcerative colitis, screening for symptoms of depression, anxiety, and psychosocial stressors at diagnosis and during flares (with referral to mental health professionals when appropriate), and encouraging regular physical activity as tolerated. Patients using dietary approaches for treatment of their IBD should be encouraged to adopt diets that are best supported by evidence and involve monitoring for the objective resolution of inflammation. We recommend formal assessment for obesity and nutritional deficiencies, and patients should be encouraged to maintain a normal body-mass index. A shared decision-making approach to contraception should include the consideration of IBD-related factors, and risk factors for venous thromboembolism. Long-term or frequent use of high-dose non-steroidal anti-inflammatory drugs should be avoided. For primary prevention of disease in the offspring of patients with IBD, we recommend avoiding passive exposure to tobacco, using antibiotics judiciously, and considering breastfeeding when able.

Smoking Behaviour Changes After Diagnosis of Inflammatory Bowel Disease and Risk of All-cause Mortality.

BACKGROUND AND AIMS: We examined smoking behaviour changes after diagnoses of Crohn's disease [CD] and ulcerative colitis [UC] and evaluated their impact on mortality. METHODS: Study population included incident CD or UC cases from three cohorts of the Nurses' Health Study [NHS], NHSII, and Health Professionals Follow-up Study. Smoking and other risk factors were prospectively assessed. Smoking behaviour changes were categorised as never, former [i.e., quit smoking before diagnosis], quitters [i.e., quit smoking after diagnosis], and current [i.e., continue smoking after diagnosis]. Follow-up for date and cause of death was completed through linkage to the National Death Index. Cox proportional hazard regression was used to estimate hazard ratios [HRs] and 95% confidence intervals [CIs]. RESULTS: Among 909 eligible CD and UC cases, 45% were never smokers, 38% were past smokers, and 16% were active smokers at the time of diagnosis. Among active smokers, 70% of patients with CD and 44% of patients with UC continued to smoke after diagnosis. In patients with CD, compared with current smokers, the multivariable-adjusted HRs [95% CI] of death were 0.19 [0.10 to 0.38] for never smokers, 0.31 [0.16 to 0.57] for former smokers, and 0.41 [0.18 to 0.93] for quitters. Similarly for UC, compared with current smokers, we observed a reduced risk of mortality for never smokers [HR = 0.23, 95% CI 0.10 to 0.51], former smokers [HR = 0.23, 95% CI 0.11 to 0.48], and quitters [HR = 0.28, 95% CI 0.11 to 0.72]. CONCLUSIONS: In three cohorts of health professionals, a substantial proportion of patients with new diagnosis of CD and UC and history of smoking continued to smoke after diagnosis. Smoking cessation around the time of diagnosis was associated with a significant reduction in mortality.

Risk Factors for Incident Inflammatory Bowel Disease According to Disease Phenotype.

BACKGROUND & AIMS: We examined whether relationships between known risk factors for Crohn's disease (CD) and ulcerative colitis (UC) differ according to disease phenotype, defined by Montreal classification, at the time of diagnosis. METHODS: We performed a prospective cohort study of 208,070 adults from the Nurses' Health Study (NHS), NHSII, and Health Professionals Follow-Up Study (HPFS). Dietary, lifestyle, and medical data were obtained at baseline and every 2-4 years. We confirmed cases of inflammatory bowel disease (IBD) and their phenotypes via medical record review. We tested for heterogeneity across CD subtypes using the likelihood ratio test and for linear heterogeneity across UC subtypes using the meta-regression method. RESULTS: We ascertained 346 cases of CD and 456 cases of UC over 5,117,021 person-years of follow-up (1986-2016 for NHS and HPFS; 1991-2017 for NHSII). Fiber intake was associated with decreased risk for ileocolonic but not ileal or colonic CD (Pheterogeneity = .04). Physical activity was associated with decreased risk of nonstricturing and nonpenetrating CD but not of penetrating CD (Pheterogeneity = .02). Higher body mass index and current smoking were associated with decreased risk of proctitis and left-sided UC but not of pan-UC (Plinear heterogeneity= .004 and .02, respectively). The associations between other risk factors examined and risk of CD and UC did not differ by disease phenotype (all Pheterogeneity > .06). CONCLUSIONS: In 3 large prospective cohorts, we observed that dietary and lifestyle risk factors for IBD may differ according to disease phenotype. These findings highlight the need for disease stratification in future epidemiologic studies.

Lifestyle factors for the prevention of inflammatory bowel disease.

OBJECTIVE: To estimate the proportion of cases of Crohn's disease (CD) and ulcerative colitis (UC) that could be prevented by modifiable lifestyle factors. DESIGN: In a prospective cohort study of US adults from the Nurses' Health Study (NHS; n=72 290), NHSII (n=93 909) and Health Professionals Follow-up Study (HPFS; n=41 871), we created modifiable risk scores (MRS; 0-6) for CD and UC based on established lifestyle risk factors, and healthy lifestyle scores (HLS; 0-9) derived from American healthy lifestyle recommendations. We calculated the population attributable risk by comparing the incidence of CD and UC between low-risk (CD-MRS≤1, UC-MRS≤2, HLS≥7) and high-risk groups. We externally validated our findings in three European cohorts: the Swedish Mammography Cohort (n=37 275), Cohort of Swedish Men (n=40 810) and European Prospective Investigation into Cancer and Nutrition (n=404 144). RESULTS: Over 5 117 021 person-years of follow-up (NHS, HPFS: 1986-2016; NHSII: 1991-2017), we documented 346 CD and 456 UC cases. Adherence to a low MRS could have prevented 42.9% (95% CI 12.2% to 66.1%) of CD and 44.4% (95% CI 9.0% to 69.8%) of UC cases. Similarly, adherence to a healthy lifestyle could have prevented 61.1% (95% CI 16.8% to 84.9%) of CD and 42.2% (95% CI 1.7% to 70.9%) of UC cases. In our validation cohorts, adherence to a low MRS and healthy lifestyle could have, respectively, prevented 43.9%-51.2% and 48.8%-60.4% of CD cases and 20.6%-27.8% and 46.8%-56.3% of UC cases. CONCLUSIONS: Across six US and European cohorts, a substantial burden of inflammatory bowel diseases risk may be preventable through lifestyle modification.

Plasma concentrations of perfluoroalkyl substances and risk of inflammatory bowel diseases in women: A nested case control analysis in the Nurses' Health Study cohorts.

BACKGROUND: Perfluoroalkyl substances (PFASs) are synthetic compounds used in a wide variety of industrial and consumer applications. An association between PFAS exposure and risk of ulcerative colitis (UC) has been reported in a highly exposed population. However, data are limited on risk of inflammatory bowel diseases (IBD) among individuals with background population levels of PFAS exposure. OBJECTIVES: We set out to examine the association between plasma PFAS concentrations and risk of IBD among women in two population-based, prospective cohort studies in which pre-diagnostic blood specimens were available. METHODS: We conducted a nested case-control study in the Nurses' Health Study and Nurses' Health Study II cohorts. We identified 73 participants with incident Crohn's disease (CD) and 80 participants with incident UC who had provided blood samples before diagnosis. Cases were matched 1:2 to IBD-free controls. Plasma concentrations of five major PFASs were measured by liquid chromatography and tandem mass spectrometry. We used conditional logistic models to estimated odds ratios for risk of IBD according to log10-transformed PFAS concentrations, adjusting for potential confounders. RESULTS: In multivariable models, we observed inverse associations between plasma concentrations of three PFASs and risk of CD (all P ≤ 0.012 for a standard deviation increase in log10PFAS). The inverse association with CD was strongest for perfluorodecanoate, where, compared to the lowest tertile, the odds ratio (OR) for the highest tertile was 0.39 (95% confidence interval, 0.17-0.92). No associations were observed between PFAS concentrations and UC risk. DISCUSSION: Our results do not support the hypothesis that elevated PFAS exposure is associated with higher risk of UC. Contrary to expectation, our data suggest that circulating concentrations of some PFASs may be inversely associated with CD development.

Ultra-processed Foods and Risk of Crohn's Disease and Ulcerative Colitis: A Prospective Cohort Study.

BACKGROUND & AIMS: The rising incidence of inflammatory bowel disease in regions undergoing Westernization has coincided with the increase in ultra-processed food (UPF) consumption over the past few decades. We aimed to examine the association between consumption of UPFs and the risk of Crohn's disease (CD) and ulcerative colitis (UC). METHODS: We performed a prospective cohort study of 3 nationwide cohorts of health professionals in the United States-the Nurses' Health Study (1986-2014), the Nurses' Health Study II (1991-2017), and the Health Professionals Follow-up Study (1986-2012). We employed Cox proportional hazards models with adjustment for confounders to estimate the hazard ratios (HRs) and 95% confidence intervals (CIs) for CD and UC according to self-reported consumption of UPFs. RESULTS: The study included 245,112 participants. Over 5,468,444 person-years of follow-up, we documented 369 incident cases of CD and 488 incident cases of UC. The median age at diagnosis was 56 years (range, 29-85 years). Compared with participants in the lowest quartile of simple updated UPF consumption, those in the highest quartile had a significantly increased risk of CD (HR, 1.70; 95% CI, 1.23-2.35; Ptrend = .0008). Among different UPF subgroups, ultra-processed breads and breakfast foods; frozen or shelf-stable ready-to-eat/heat meals; and sauces, cheeses, spreads, and gravies showed the strongest positive associations with CD risk (HR per 1 standard deviation increase in intake, 1.18 [95% CI, 1.07-1.29], 1.11 [95% CI, 1.01-1.22], and 1.14 [95% CI, 1.02-1.27], respectively). There was no consistent association between UPF intake and UC risk. CONCLUSIONS: Higher UPF intake was associated with an increased risk of incident CD. Further studies are needed to identify specific contributory dietary components.

Clinical Characteristics and Treatment Response in Microscopic Colitis Based on Age at Diagnosis: A Multicenter Retrospective Study.

BACKGROUND: Microscopic colitis (MC) primarily affects older adults; thus, data in younger patients are scarce. AIMS: To compare clinical characteristics and treatment response by age at diagnosis. METHODS: This retrospective cohort study was performed at Mayo Clinic and Massachusetts General Hospital. Patients were chosen consecutively using established databases. Patients were 'younger' if age at diagnosis was ≤ 50 years and 'older' if age > 50 years. Treatment outcomes were captured for induction (12 ± 4 weeks), based on the total number of daily stools, and defined as remission (complete resolution), response (≥ 50% improvement), non-response (< 50% improvement), and intolerance. Patients were considered 'responders' if they had remission or response and 'non-responders' if they had non-response or intolerance. RESULTS: We included 295 patients (52 younger, 243 older). There were no differences in sex, race, MC subtype, and diarrhea severity between groups (all P > 0.05). Younger patients were more likely to have celiac disease (17.3% vs. 5.8%, P = 0.01), while older patients had higher BMI (mean 25.0 vs. 23.8 kg/m2, P = 0.04) were more likely smokers (53.9% vs. 34.6%, P = 0.01) and use NSAIDs (48.6% vs. 15.4%, P < 0.01) and statins (22.6% vs. 3.8%, P < 0.01). Overall treatment response was highest for budesonide (88.3%) and did not differ when comparing older to younger patients (90.6% vs. 77.8%, P = 0.12) or by MC subtype (LC, 81.5% vs. CC, 92.9%, P = 0.07). CONCLUSIONS: There are no significant differences in MC treatment response based on age or disease subtype. These findings support treating patients with MC based on symptom severity rather than age.

Dietary Gluten Intake Is Not Associated With Risk of Inflammatory Bowel Disease in US Adults Without Celiac Disease.

BACKGROUND & AIMS: Diet is thought to play a role in the development of inflammatory bowel disease (IBD), though it is unknown whether gluten intake confers risk of IBD. The aim of this study was to determine the relationship between gluten intake and risk of incident Crohn's disease (CD) and ulcerative colitis (UC). METHODS: We performed a prospective cohort study of 208,280 US participants from the Nurses' Health Study (1986-2016), Nurses' Health Study II (1991-2017), and the Health Professionals Follow-up Study (1986-2016) who did not have IBD at baseline or celiac disease, and who completed semiquantitative food frequency questionnaires. We used Cox proportional hazards modeling to estimate the risk of IBD according to quintiles of cumulative average energy-adjusted dietary gluten intake over the follow-up period. RESULTS: We documented 337 CD cases and 447 UC cases over 5,115,265 person-years of follow-up evaluation. Dietary gluten intake was not associated with risk of IBD. Compared with participants in the lowest quintile of gluten intake, the adjusted hazard ratios and 95% CIs for participants in the highest quintile of gluten intake were 1.16 (95% CI, 0.82-1.64; Ptrend = .41) for CD and 1.04 (95% CI, 0.75-1.44; Ptrend = .64) for UC. Adjusting for primary sources of gluten intake did not materially change our estimates. CONCLUSIONS: In 3 large adult US prospective cohorts, gluten intake was not associated with risk of CD or UC. Our findings are reassuring at a time when consumption of gluten has been increasingly perceived as a trigger for chronic gastrointestinal diseases.

Microscopic colitis.

Microscopic colitis (MC) is an inflammatory disease of the large intestine associated with urgent watery diarrhoea. MC may occur in people of all ages, although the disease primarily affects older women. Once believed to be rare, MC is now known to be a common cause of chronic watery diarrhoea in high-income countries, affecting 1 in 115 women and 1 in 286 men during their lifetime in Swedish population-based estimates. An inappropriate immune response to disturbances in the gut microenvironment is implicated in the pathogenesis of MC. Evidence also supports an underlying genetic basis for disease. The diagnosis of MC relies on clinical symptoms and microscopic assessment of colonic biopsy samples. MC is categorized histologically into collagenous colitis, lymphocytic colitis and their incomplete forms. The mainstay of treatment includes the use of budesonide, with or without adjunctive therapies, and withdrawal of offending drugs. Emerging studies suggest a role for biologicals and immunosuppressive therapies for the management of budesonide-refractory or budesonide-dependent disease. MC can have a substantial negative effect on patient quality of life. The outlook for MC includes a better understanding of the immune response, genetics and the microbiome in disease pathogenesis along with progress in disease management through robust clinical trials.

Healthy Lifestyle Is Associated With Reduced Mortality in Patients With Inflammatory Bowel Diseases.

BACKGROUND & AIMS: It is not clear whether a healthy lifestyle affects mortality of patients with inflammatory bowel diseases (IBD), including Crohn's disease (CD) and ulcerative colitis (UC). METHODS: We collected data form the Nurses' Health Study (1986-2014), Nurses' Health Study II (1991-2015), and Health Professionals Follow-up Study (1986-2014), which assess lifestyles with serial questionnaires. We estimated joint and individual associations between 5 healthy lifestyle factors after IBD diagnosis (never smoking, body mass index 18.5-24.9 kg/m2, vigorous physical activity in the highest 50% with non-zero value, alternate Mediterranean diet score ≥4, and light drinking [0.1-5.0 g/d]) and mortality using Cox proportional hazards models. RESULTS: We documented 83 deaths in 363 patients with CD during 4741 person-years and 80 deaths in 465 patients with UC during 6061 person-years. The median age of IBD diagnosis was 55 y. Compared to patients with IBD with no healthy lifestyle factors, patients with IBD with 3-5 healthy lifestyle factors had a significant reduction in all-cause mortality (hazard ratio [HR], 0.29; 95% CI, 0.16-0.52; Ptrend < .0001). This reduction was significant in patients with CD (Ptrend = .003) as well as in patients with UC (Ptrend = .0003). Individual associations were more than 25 pack-years (HR, 1.92; 95% CI, 1.24-2.97; Ptrend < .0001), physical activity (HR according to quintiles, 0.55-0.31; Ptrend = .001), Mediterranean diet (HR, 0.69; 95% CI, 0.49-0.98), and alcohol consumption (HR0.1-5 g/d 0.61; 95% CI, 0.39-0.95 vs HR>15 g/d 1.84; 95% CI, 1.02-3.32). The findings did not change when we adjusted for family history of IBD, immunomodulator use, and IBD-related surgery. CONCLUSIONS: In an analysis of data from 3 large cohort studies, we associated adherence to a healthy lifestyle with reduced mortality in patients with CD or UC.

Immunosuppressive Therapy and Risk of COVID-19 Infection in Patients With Inflammatory Bowel Diseases.

BACKGROUND: The effect of immunosuppressive treatment for immune-mediated diseases on risk of the novel coronavirus disease 2019 (COVID-19) has not been established. We aimed to define the effect of targeted biologic and immunomodulator therapy on risk of COVID-19 in a multi-institutional cohort of patients with inflammatory bowel disease (IBD). METHODS: We identified patients 18 years and older who received care for IBD at Partners Healthcare between January 2019 and April 2020. The primary outcome was development of COVID-19 defined as a positive polymerase chain reaction test for severe acute respiratory syndrome coronavirus 2. Multivariable regression models were used to examine the effect of immunosuppression on risk of COVID-19 and its outcomes. RESULTS: In a cohort of 5302 IBD patients, 39 (0.7%) developed COVID-19. There was no difference in age, sex, or race between IBD patients with and without COVID-19. The rate of COVID-19 was similar between patients treated with immunosuppression (0.8%) compared with those who were not (0.64%; P = 0.55). After adjusting for age, sex, race, and comorbidities, use of immunosuppressive therapy was not associated with an increased risk of COVID-19 (odds ratio, 1.73; 95% confidence interval, 0.82-3.63). The presence of obesity was associated with a higher risk of COVID-19 (odds ratio, 8.29; 95% confidence interval, 3.72-18.47). There were 7 hospitalizations, 3 intensive care unit stays, and 1 death. Older age and obesity but not immunosuppressive treatment were associated with severe COVID-19 infection. CONCLUSIONS: The use of systemic immunosuppression was not associated with an increased risk of COVID-19 in a multi-institutional cohort of patients with IBD.

Yield of Random Biopsies During Colonoscopies in Inflammatory Bowel Disease Patients Undergoing Dysplasia Surveillance.

BACKGROUND: The development of chromoendoscopy (CE) and high definition endoscopy (HDE) has improved detection of subtle colonic dysplasia in patients with inflammatory bowel diseases (IBDs). The role of random biopsies for dysplasia surveillance is unclear. METHODS: We reviewed patients with IBD who underwent a CE or HDE colonoscopy and had colonic dysplasia detected. Detection of dysplasia was classified as either visible or random and graded as low grade dysplasia (LGD), high grade dysplasia (HGD), or indefinite for dysplasia. Multivariable regression adjusted for relevant confounders examined the predictors of dysplasia detectable on random biopsies alone. RESULTS: The study included 300 patients (203 ulcerative colitis, 97 Crohn's disease with colonic involvement) contributing 442 colonoscopies; the mean disease duration was 24.5 years; 7.2% had primary sclerosing cholangitis (PSC). Three hundred sixty-two colonoscopies (82%) had only visible dysplasia, 52 (12%) had only random dysplasia, and 28 (6%) had both visible and random dysplasia. Longer disease duration (odds ratio, 1.04; 95% CI, 1.01-1.07), active inflammation (odds ratio, 2.89; 95% CI, 1.26-6.67), and concomitant PSC (odds ratio, 3.66; 95% CI, 1.21-11.08) were associated with detecting dysplasia on random biopsies compared with visible lesions. Patients with random dysplasia (21%) or both random and visible dysplasia (21%) were more likely to undergo surgical resection compared with those with only visible dysplasia (5%; P < 0.001) and have subsequent development of colorectal cancer (15%, 7%, 1%, respectively; P < 0.0001). CONCLUSION: Nearly one fifth of dysplasia detected in patients with IBD was found on random biopsies. Patients with high risk characteristics may benefit from continuing the practice of random biopsies during surveillance examinations.

Immune-mediated diseases and risk of Crohn's disease or ulcerative colitis: a prospective cohort study.

BACKGROUND: Although immune-mediated diseases (IMDs) including inflammatory bowel diseases (IBDs) are known to cluster, to what extent this is due to common environmental influences is unknown. AIM: To examine the incidence of IBD in individuals with another IMD. METHODS: We used data from the prospective Nurses' Health Study II cohort (1995-2017) to examine the effect of diagnoses of several common IMDs on subsequent risk of Crohn's disease (CD) or ulcerative colitis (UC) using Cox proportional hazards models, adjusting for detailed diet and lifestyle confounders. RESULTS: We documented 132 cases of CD and 186 cases of UC over 2 016 163 person-years of follow-up (median age at IBD diagnosis 50 years). Compared to participants with no history of IMD, the HRs of CD for those with 1 and ≥ 2 IMDs were 2.57 (95% CI 1.77-3.74) and 2.74 (95% CI 1.36 to 5.49), respectively (Ptrend  < 0.0001). This association was only modestly attenuated by adjustment for environmental risk factors (HR 2.35 and 2.46, respectively). The risk of UC was not increased, with multivariable-adjusted HRs of 1.22 (95% CI 0.85-1.76) and 1.33 (95% CI 0.67-2.65) for those with 1 and ≥ 2 IMDs, respectively, compared to those with none (Ptrend 0.16) (Pheterogeneity comparing CD and UC 0.037). Asthma, atopic dermatitis, psoriasis and rosacea were individually associated with higher risk of CD (HR ranging from 2.15 to 3.39) but not UC. CONCLUSIONS: Individuals with one or more IMDs are at an increased risk for CD but not UC.

Dietary Inflammatory Potential and Risk of Crohn's Disease and Ulcerative Colitis.

BACKGROUND & AIMS: Inflammation is a potential mechanism through which diet modulates the onset of inflammatory bowel disease. We analyzed data from 3 large prospective cohorts to determine the effects of dietary inflammatory potential on the risk of developing Crohn's disease (CD) and ulcerative colitis (UC). METHODS: We collected data from 166,903 women and 41,931 men in the Nurses' Health Study (1984-2014), Nurses' Health Study II (1991-2015), and Health Professionals Follow-up Study (1986-2012). Empirical dietary inflammatory pattern (EDIP) scores were calculated based on the weighted sums of 18 food groups obtained via food frequency questionnaires. Self-reported CD and UC were confirmed by medical record review. Cox proportional hazards models were used to calculate hazard ratios (HRs) and 95% confidence intervals (CIs). RESULTS: We documented 328 cases of CD and 428 cases of UC over 4,949,938 person-years of follow-up. The median age at IBD diagnosis was 55 years (range 29-85 years). Compared with participants in the lowest quartile of cumulative average EDIP score, those in the highest quartile (highest dietary inflammatory potential) had a 51% higher risk of CD (HR 1.51; 95% CI 1.10-2.07; Ptrend = .01). Compared with participants with persistently low EDIP scores (at 2 time points, separated by 8 years), those with a shift from a low to high inflammatory potential of diet or persistently consumed a proinflammatory diet had greater risk of CD (HR 2.05; 95% CI 1.10-3.79 and HR 1.77; 95% CI 1.10-2.84). In contrast, dietary inflammatory potential was not associated with the risk of developing UC (Ptrend = .62). CONCLUSIONS: In an analysis of 3 large prospective cohorts, we found dietary patterns with high inflammatory potential to be associated with increased risk of CD but not UC.