Eosinophilic Esophagitis and Autoimmune Thyroid Disease: A Population‐Based Matched Cohort Study

BACKGROUND: Eosinophilic esophagitis (EoE) is an immune-mediated disease typically presenting with esophageal symptoms. Although prior exploratory studies on the autoimmune comorbidity of EoE have indicated a possible association with autoimmune thyroid disease (AITD), this relationship has not been examined in detail. METHODS: Using the nationwide ESPRESSO cohort consisting of data from all 28 pathology departments in Sweden, we identified patients with biopsy-confirmed EoE diagnosed between 2006-2023. Each EoE patient was compared with general-population references matched on sex, age, county of residence, and calendar year of diagnosis. A secondary reference group consisted of full siblings of EoE patients. Cox proportional hazard model was used to estimate the hazard ratio (HR) of future AITD, whereas a logistic regression model was used to estimate the odds ratio (OR) of prior AITD. RESULTS: During follow-up, 70/5801 EoE patients developed AITD (incidence rate, 2.14/1000 person-years) compared to 271/27,407 references (1.74/1000 person-years), corresponding to an HR of 1.18 (95% CI, 0.91-1.54). Compared to sibling comparators, the HR was 1.27 (0.84-1.94). The prevalence of prior AITD was 3.9% in EoE, compared with 3.0% in references, corresponding to an OR of 1.29 (1.10-1.49). Notably, in childhood-onset EoE, the HR of future AITD was 2.53 (1.18-5.45) and the OR of prior AITD was 4.71 (2.34-9.43). CONCLUSIONS: EoE was associated with prior AITD, but not with future AITD. Childhood-onset EoE was however associated with both prior and future AITD. Physicians diagnosing EoE should be observant of symptoms indicative of AITD, especially in childhood-onset EoE.