Supplementary Material for: Characteristics and long-term prognosis of celiac disease: comparisons between patients diagnosed either in childhood or adulthood

Introduction: It is plausible but not yet proven that early celiac disease diagnosis prevents long-term complications of untreated disease. Our aim was to compare phenotype and health outcomes in currently adult celiac disease patients diagnosed either in childhood (<18 years) or adulthood. Methods: Data on 1059 patients were collected from medical records at diagnosis and with questionnaires and structured interviews after long-term follow-up. Associations between timing of diagnosis and long-term health were studied with regression models. Results: Patients diagnosed in childhood (n=239) were more often males (32% vs. 23%, p=0.004), currently younger (27 vs. 54 years, p<0.001), more often screen-detected (20% vs. 14%, p<0.001), and reported lower adherence to gluten-free diet in adulthood (92% vs. 97%, p<0.001) than those diagnosed in adulthood (n=820). After adjusting for clinico-demographic variables and dietary adherence, patients diagnosed in childhood had fewer miscarriages (OR 0.41 [95% CI 0.21-0.80]) but more allergies (1.75 [1.11-2.76]), dermatological diseases excluding dermatitis herpetiformis (1.99 [1.11-3.58]), asthma (2.28 [1.16-4.48]), and depression (2.84 [1.24-6.50]) in adulthood. The groups were comparable in other comorbidities including type 1 diabetes and autoimmune thyroidal diseases, persistent symptoms, and quality of life. Conclusion: Diagnosis in childhood compared to adulthood was associated with disease phenotype and its effects on long-term comorbidities are complex.