Bidirectional risk of autoimmune disease and eosinophilic esophagitis in Sweden

Eosinophilic esophagitis (EoE) shares several risk factors with other autoimmune diseases, but population-based studies in this field are limited.

Using the Swedish nationwide histopathology cohort Epidemiology Strengthened by histopathology Reports in Sweden (ESPRESSO), we identified all patients in Sweden with EoE and matched them by age, sex, county of residence and calendar year with up to 5 general population reference individuals. Using Cox regression modelling, we calculated hazard ratios (HRs) for future autoimmune disease as recorded in the National Patient Register. Using conditional logistic regression, we also calculated odds ratios (ORs) for autoimmune disease prior to EoE.

We identified 1477 individuals with EoE and 6933 matched reference individuals from the general population. During a median follow-up of 8 years, 44 EoE patients (2.98%) and 113 reference individuals (1.63%) developed autoimmune disease with incidence rates of 3.54 and 1.93 per 1000 person-years, respectively. The adjusted HR for subsequent autoimmune disease was 1.83 (95% CI = 1.29-2.59) among patients with EoE compared to general population reference individuals. Excluding inflammatory bowel disease and celiac disease from our composite outcome, the adjusted HR for non-gastrointestinal autoimmunity was 1.45 (95% CI = 0.93-2.25). EoE was also associated with earlier autoimmune disease with 7.9% of EoE patients having a record of an autoimmune disease before EoE, as compared with 2.9% of reference individuals (OR = 2.92; 95% CI = 2.34-3.65).

EoE was associated with both antecedent and subsequent autoimmune disease, which was strongly driven by gastrointestinal autoimmune conditions. While associations with non-gastrointestinal autoimmune diseases did not reach statistical significance in the present analysis, they warrant further investigation. Clinicians treating patients with EoE should be aware of the increased risk of concomitant or future autoimmunity.