Purpose Coeliac disease (CD) is a common disorder and affects about 1% of the population worldwide. CD in the Trøndelag Health Study (HUNT) is a population-based cohort study which was established to provide new knowledge about CD that can improve the diagnostics and management, prevent the onset or progression and expand the knowledge about the role of genetics of the disease.Participants The cohort is based on the fourth wave of the population-based HUNT study (HUNT4), Norway, performed during 2017–2019, also including linkage to hospital records and the Norwegian Patient Registry (NPR). A total of 54 541 HUNT4 participants with available sera were screened for CD by serology. All seropositive participants were invited to a clinical assessment, including endoscopy with duodenal biopsies, during 2019–2023.Findings to date A total of 1107 HUNT4 participants (2%) were seropositive for CD and 1048 were eligible for clinical assessment, including biopsy. Of these, 724 participants attended the clinical assessment and 482 were identified with CD. In addition, 371 participants with CD were identified through the hospital records and NPR. In total, 853 participants in HUNT4 with biopsy-verified CD diagnosis were identified.Future plans All participants in the study will be invited to a follow-up assessment after at least 1 year, including repeated standard serological testing, endoscopy and tissue sampling. The collected data and material will be used to establish the true population-based prevalence of CD. The consequences of CD, including symptoms, deficiencies and comorbidity, will be investigated and possible triggers and predictors, will be studied. With access to serum samples from the previous HUNT surveys in HUNT Biobank, serological signs of CD in prediagnostic samples of seropositive individuals will be used. Genetic studies will identify new CD markers, assess genotype–phenotype links and explore gene–environment correlations.Registration clinicaltrials.gov identifier: NCT04041622.
