The IMAGINE Cohort Study will identify and recruit a cohort of 8000 patients with IBS, IBD and healthy controls (2000 of each) who will be assessed in terms of their psychological status, dietary intake, gut microbiome, metabolomic and inflammatory markers and genotype, health-related quality of life, and health care resource use and associated costs. The cohort and healthy controls will be followed prospectively for up to 5 years after the completion of study enrolment.

The goal of the screening visit is to confirm that the Subject/Healthy Control is willing to participate in the study and that they meet the eligibility criteria for the study.

The screening visit will include:

i. Obtaining signed informed consent /assent to screen for eligibility (Consent/Assent-Subject, Consent/Assent-Control).

ii. Reviewing the subject/control for eligibility (per inclusion/exclusion criteria).

Subjects will be identified through several pathways: 1) Patients with confirmed IBS or IBD in existing site databases who have previously consented to be contacted for future IBS studies or those approached in clinic with a recent confirmed diagnosis of IBS/IBD and consent to participate and 2) patients with self-reported IBS or IBD who contact the site coordinator or who are identified in clinic with an unsubstantiated diagnosis of IBS/IBD.

Subjects with a confirmed diagnosis of IBS or IBD and who have given prior consent to be contacted, will be prescreened by phone or in person. All others will be invited to a screening visit and the study rationale and design will be explained. Interested subjects will be asked to provide informed written consent. Eligibility will then be confirmed and subjects will complete the questionnaires and provide the necessary samples at this and a follow-up visit if necessary.

Subjects who do not meet the diagnostic criteria for IBS or IBD and wish to have the diagnosis confirmed, will be advised to see their family physician for any necessary diagnostic testing. A letter to the family physician will be provided stating that the patient had been approached about the study and that the diagnosis of IBS/IBD could not been made due to an absence of testing and/or failure to meet the predefined criteria. Patients will also be informed if they fail to meet other eligibility criteria that would exclude them from the study.

When eligibility for subjects and healthy controls has been confirmed, the following questionnaires will be answered and samples obtained:

• Blood samples
• Metabolomic urine sample
• Stool sample (metagenomics, metabolomics, fecal calprotectin (FCAL) and β-defensins)
• Demographic questionnaire
• Quality of life questionnaire (EQ-5D for adults)
• Food Frequency Questionnaire
• Psychological questionnaires (pediatric for ≤ 17 years, adult for those > 17 years)
• Optional on-line additional psychological questionnaires for adults
• Disease specific questionnaires (UC, CD and IBS - UC and CD further divided into pediatric for ≤ 17 years, adult for those > 17 years)
• General gastrointestinal symptom questionnaires (Short for Leeds Dyspepsia Questionnaire, PROMIS diarrhea, PROMIS abdominal pain, PROMIS constipation and PROMIS bloating).
• Workplace productivity questionnaire.

Inclusion Criteria:

• Each control that agrees to participate will undergo an initial screening questionnaire to confirm that they are healthy and have no gastrointestinal symptoms using the ROME IV Questionnaire.

Exclusion Criteria:

• • major gastrointestinal surgery (Roux en y, bowel resection)

  • any major comorbid chronic condition (e.g. decompensated liver disease or malignancy, lung or cardiac disease, active HIV, diabetes mellitus requiring medication,
  • difficulties with communication or conditions affecting ability to provide informed consent,
  • unable to communicate in the language of the cohort study (English or French)
  • those who do not wish to participate in this study
  • diagnosis of schizophrenia
  • diagnosis of eating disorder

There will be 17 recruitment centres across Canada responsible for recruitment of 2000 subjects with CD, 2000 subjects with UC, 2000 subjects with IBS and 2000 healthy controls. Each centre will be required to obtain appropriate ethics approval prior to initiating study recruitment.