To Örebro University

BACKGROUND: Celiac disease (CD) has been linked to inflammatory bowel disease (IBD) but previous reports have been inconsistent and may have been affected by surveillance bias.

METHODS: Matched birth cohort study in Friuli-Venezia Giulia Region, Italy. We identified 1294 individuals with CD aged 0 to 23 years at diagnosis using pathology reports, hospital discharge records, or copayment exemptions. Each CD individual was matched with up to 5 general population reference individuals from the regional Medical Birth Register in Friuli-Venezia Giulia (n = 5681). As secondary comparison groups, we used individuals undergoing small intestinal biopsy but not having villous atrophy (either Marsh 0-1-2 or exclusively Marsh 0). Individuals with IBD were identified through hospital discharge records or copayment exemptions. Conditional logistic regression was used to estimate odds ratios (ORs) for having IBD among CD individuals (before or after CD diagnosis) compared with their matched references.

RESULTS: Overall 35 individuals with IBD were identified (29 with CD and 6 general population controls). This corresponded to an increased risk of IBD in CD (OR = 24.17; 95% CI, 10.03-58.21). However, compared with individuals with Marsh 0-1-2 the OR decreased to 1.41 (95% CI, 0.91-2.18) and restricting our comparison group to individuals with Marsh 0, the OR was 1.28 (95% CI, 0.61-2.70).

CONCLUSIONS: In conclusion, this article found a highly increased risk of IBD in individuals with CD when comparing with the general population. Bias is the likely explanation for the very high risk increase for IBD in CD because the excess risk was substantially lower when we used individuals with a small intestinal biopsy without villous atrophy as our reference.