Ina Lervåg Andersen

Background A large proportion of individuals with coeliac disease (CeD) remain undiagnosed. Objective The aim of this study was to assess serological screening for CeD in the adult general population. Design The study was based on the fourth Trøndelag Health Study, a population-based study performed 2017–2019 in Nord-Trøndelag County, Norway, including 56 042 participants >20 years of age (54% participation rate). Serum samples were analysed with a dual antitransglutaminase 2 (TG2) IgA and IgG assay and seropositive participants were invited to endoscopy with duodenal biopsies. A CeD diagnosis was given if mucosal damage (Marsh grade 3) was found. Results Histological evaluation of 657 seropositive participants confirmed CeD in 423. The positive predictive value (PPV) of a positive TG2 IgA was 73.3% (95% CI 69.7% to 77.0%) for biopsy-confirmed CeD. TG2 IgA ≥10 times the upper limit of normal (ULN), as used in the no-biopsy approach in children, increased the PPV to 88.1% (95% CI 84.8% to 91.4%). Primary TG2 IgG response was found in 87 participants, five of whom had biopsy-confirmed CeD. One of the participants with CeD primarily responding with TG2 IgG was IgA deficient. The PPV of a positive TG2 IgG was 5.8% (95% CI 1.9% to 12.9%) and of TG2 IgG ≥10× ULN was 9.5% (95% CI 1.2% to 30.4%) for biopsy-confirmed CeD in TG2 IgA-negative individuals. Conclusion The TG2 IgA assay showed excellent abilities as a screening tool for CeD in the adult general population. However, the diagnostic accuracy of TG2 IgG was too poor for selectively identifying individuals with CeD.

Objective. The objective was to assess radiographic periodontal bone loss in a population with previously undiagnosed celiac disease, and to compare it to a reference group without celiac disease. Background. Periodontitis and celiac disease are chronic inflammatory diseases with possible similar features related to immune reactions and microbial dysbiosis. The relationship between these two diseases is not clear. Methods. Clinical variables, blood samples, and answers to questionnaires were collected from participants in the fourth Trøndelag Health Study (HUNT4). Celiac disease was determined based on transglutaminase 2 (TG2), immunoglobulin A (IgA), and G (IgG) in serum samples. Seropositive individuals were invited to endoscopic examination and tissue sampling. Radiographically assessed bone loss caused by periodontitis in two different levels of severity was applied as outcome, that is, ≥15% and >33% of root length. Bone loss was determined in panoramic images in participants that had attended radiographic examination in the HUNT4 Oral Health Study or in the HUNT4 Coeliac Disease Study. The association between previously undiagnosed celiac disease and radiographic bone loss was estimated by adjusted Poisson regression models. Results. Radiographic assessment was completed in 485 individuals with celiac disease determined by positive serology and in 4,727 individuals with negative serology (without celiac disease). Compared to nonceliacs, seropositive participants were less likely to present with ≥15% radiographic bone loss (prevalence ratio (PR) 0.89 (95% CI 0.84–0.96). A similar association was also observed after histopathological confirmation of celiac disease (PR 0.89 (95% CI 0.82–0.98). No association between undiagnosed celiac disease and periodontal bone loss was observed when analyses were limited to individuals with severe bone loss (>33%). Conclusion. In this study of previously undiagnosed celiac disease and periodontal bone loss, newly diagnosed celiac disease was associated with less likelihood of presenting with ≥15% radiographic bone loss compared to a nonceliac reference group.