Illness Identity in Adolescents With Celiac Disease

Objectives: The aim was to examine the reliability and validity of the Illness Identity Questionnaire (IIQ) among adolescents with celiac disease (CD), to describe their illness identity characteristics, and to examine relationships between illness identity and self‐reported participation in food‐related activities and quality of life. Methods: Adolescents with CD (n = 91) were recruited for this cross‐sectional study via social media interest groups. Participants completed online questionnaires: the IIQ, the CD Children's Activities Chart (CD‐Chart), and the Pediatric Quality of Life Inventory (PedsQL). Results: Internal reliability was established for IIQ items (α = 0.87) and for its 4 components (α = 0.75‐‐0.90). The positive components (acceptance, enrichment) significantly differed from the negative components (rejection, engulfment), t (90) = 11.45, P  < 0.001, d  =  1.98. Feelings were more positive (M = 3.48, SD = 0.67) than negative (M = 2.06, SD = 0.76). The total IIQ was positively associated with the CD‐Chart amount of activities ( r  = 0.30, P  < 0.01) and enjoyment ( r  = 0.34, P  < 0.001) and with the PedsQL social scale ( r  = 0.53, P  < 0.001). Conclusions: The IIQ established acceptable reliability and validity. In all, the adolescents with CD exhibited an illness identity profile that was more positive and adaptive than negative. The IIQ can contribute to understanding the developmental status of illness identity during the critical transition process from adolescence to adulthood.