Population-based screening for celiac disease reveals that the majority of patients are undiagnosed and improve on a gluten-free diet

Abstract

The impact of a gluten-free diet (GFD) on screen-detected celiac disease (CD) is currently ambiguous. We aimed to identify the population-based prevalence of undiagnosed adult CD and examine the impact of a GFD on screen-detected CD. In total, 12,981 adults participated in a population-based health study in Tromsø, Norway. Participants with increased levels of anti-tissue transglutaminase-2 IgA or anti-deamidated gliadin peptide IgG were invited to undergo gastroduodenoscopy with both histological and immunohistochemical examination of small-bowel biopsies. The prevalence of previously diagnosed CD was 0.37%. Additionally, the prevalence of previously undiagnosed CD was 1.10%. Thus, 1.47% of the population had CD, of whom 75% were previously undiagnosed. A GFD resulted in significant improvements in overall gastrointestinal symptoms, diarrhea, and health-related quality of life, with reduced abdominal discomfort (76%) and improved levels of energy (58%). The large majority of patients with adult CD were undiagnosed and benefited from a GFD with reduced gastrointestinal symptoms and improved health-related quality of life. In clinical practice, there should be a low threshold for CD testing even in the absence of abdominal complaints because most adult patients appear to consider their symptoms a part of their normal state and therefore remain untested and undiagnosed.Trial registration: Clinical Trials. Gov Identifier: NCT01695681.

Figure 1

Flowchart of the study. CD celiac disease, TG2-IgA tissue transglutaminase 2-IgA antibodies, DGP-IgG deamidated gliadin peptide-IgG antibodies.

Figure 2

Serum TG2-IgA titers in participants with and without a biopsy-verified diagnosis. Serum TG2-IgA levels in participants with a biopsy-verified diagnosis (left panel, n = 173) had a similar distribution to those in participants who were not biopsied (right panel, n = 103, light-blue rhombi). The horizontal line indicates median TG2-IgA titers (U/mL). TG2-IgA tissue transglutaminase 2-IgA antibodies.

Figure 3

Distribution of serum DGP-IgG and TG2-IgA according to celiac disease status. Serum DGP-IgG (x-axis) and TG2-IgA (y-axis) from the participants (n = 173) with a biopsy-verified diagnosis. Although the DGP-IgG and TG2-IgA titers were significantly correlated in CD patients (p < 0.001, Spearman r = 0.45), they were not correlated in participants without CD. DGP-IgG deamidated gliadin peptide-IgG antibodies, TG2-IgA tissue transglutaminase 2-IgA antibodies, n number of participants.

Figure 4

Differences in gastrointestinal symptoms and health-related quality of life on a GFD. Score differences in individuals with a biopsy-proven CD (n = 79) between inclusion and follow-up on a GFD. The direction of change in the GSRS has been reversed. GSRS Gastrointestinal Symptoms Rating Scale, PGWB Psychological General Well-Being.

Figure 5

Self-reported changes (%) in symptoms at follow-up on a GFD. n = 78 (one missing), p < 0.05 for the model (χ² test).