PREdiCCt — the PRognostic effect of Environmental factors in Crohn’s and Colitis — is a UK-wide prospective cohort designed to understand what precedes an IBD flare. It brings together information on diet, lifestyle, psychosocial factors, the microbiome and markers of inflammation.
Following people over time
The study recruited 2,629 people with Crohn’s disease, ulcerative colitis or IBD unclassified in self-reported remission across 47 UK centres between 2016 and 2020. Participants were followed for a median of 4.1 years. Monthly patient reports were considered alongside objective evidence of inflammation and treatment escalation, allowing the study to examine different definitions of flare.
What the first main results showed
The published study found that higher baseline faecal calprotectin was strongly associated with later flares. Compared with levels below 50 µg/g, levels of at least 250 µg/g were associated with adjusted hazard ratios of 2.22 for patient-reported flares and 3.25 for objectively defined flares.
Higher habitual meat intake was associated with objectively defined flares in ulcerative colitis. No consistent associations were observed for ultra-processed foods, fibre or polyunsaturated fatty acids. These are observational findings: they do not establish that changing one food or nutrient prevents a flare, or that an association is absent in every patient group.
Current work
Further analyses examine psychosocial factors and the gut microbiome. The programme asks how everyday exposures, patients’ experience and underlying inflammation interact, and which questions should be tested in future studies. Its purpose is to strengthen the evidence for personalised advice while recognising that symptoms, objective inflammation and quality of life each matter.