Functional Gastrointestinal Disorders and Associated Health Impairment in Individuals with Celiac Disease

Background & Aims: Individuals with celiac disease (CD) can experience persisting gastrointestinal symptoms despite adhering to a gluten-free diet (GFD). This may be due to functional gastrointestinal disorders (FGIDs), although there is little data on its prevalence and associated factors. Methods: An online health questionnaire was completed by adult members of Celiac UK in October 2018. The survey included validated questions on Rome IV FGIDs, nongastrointestinal somatic symptoms, anxiety, depression, quality of life, health care use, GFD duration, and its adherence using the celiac dietary adherence test score (with a value ≤ 13 indicating optimal adherence). The prevalence of FGIDs and associated health impairment in the celiac cohort was compared against an age- and sex-matched population-based control group. Results: Of the 863 individuals with CD (73% female; mean age, 61 years), all were taking a GFD for at least 1 year, with 96% declaring that they have been on the diet for 2 or more years (2–4 years, 20%; ≥5 years, 76%). The adherence to a GFD was deemed optimal in 61% (n = 523), with the remaining 39% (n = 340) nonadherent. Those adhering to a GFD fulfilled criteria for a FGID in approximately one-half of cases, although this was significantly lower than nonadherent subjects (51% vs 75%; odds ratio [OR], 2.0; P < .001). However, the prevalence of FGIDs in GFD-adherent subjects was significantly higher than in matched population-based controls (35%; OR, 2.0; P < .001). This was accounted for by functional bowel (46% vs 31%; OR, 1.9; P < .0001) and anorectal disorders (14.5% vs 9.3%; OR, 1.7; P = .02) but not functional esophageal (7.6% vs 6.1%; P = .36) or gastroduodenal disorders (8.7% vs 7.4%; P = .47). Finally, GFD-adherent subjects with FGIDs were significantly more likely than their counterparts without FGIDs to have abnormal levels of anxiety (5% vs 2%; OR, 2.8; P = .04), depression (7% vs 2%; OR, 3.6; P = .01), somatization (31% vs 8%; OR, 5.1; P < .0001), and reduced quality of life (P < .0001). Conclusion: One in 2 people with CD, despite having been on a GFD for a number of years and demonstrating optimal adherence, have ongoing symptoms compatible with a Rome IV FGID. This is 2-fold the odds of FGIDs seen in age- and sex-matched controls. The presence of FGIDs is associated with significant health impairment, including psychological comorbidity. Addressing disorders of gut-brain interaction might improve outcomes in this specific group of patients.