Perceived Familial Risk, Dietary Beliefs, and Self-Reported Family Dietary Changes Among Unaffected First-Degree Relatives of Individuals with Inflammatory Bowel Disease: A Mixed Methods Study in Greece

Background/Objectives: Although the exact etiology of Inflammatory Bowel Diseases (IBD) is not yet fully understood, recent evidence suggests that both genetic and dietary factors are involved in their pathogenesis. The aim of the present exploratory study was to investigate how first-degree relatives (FDRs) of individuals with IBD perceive familial risk and the role of diet in IBD onset and prevention. Methods: A mixed methods approach was followed. A total of 103 unaffected FDRs of individuals living with IBD in Greece participated in an online questionnaire examining demographic characteristics, disease-related knowledge, risk perception, and beliefs about the role of diet in IBD. In parallel, 16 semi-structured interviews explored participants’ beliefs, self-reported dietary practices, and the factors shaping them using a framework analysis guided by the Health Belief Model. Results: Exploratory quantitative findings indicated that belief in the role of diet was associated with higher odds of self-reported family dietary changes, while belief in genetic risk was associated with lower odds of self-reported family dietary changes. The findings did not characterize the nature, maintenance, or motivation of these changes. Qualitative findings provided a deeper understanding of participants’ beliefs, highlighting that diet was mainly viewed as relevant to IBD management rather than prevention. Fear of disease onset and healthcare professional guidance were perceived as key facilitators of dietary changes. Conclusions: Our findings highlight heterogeneous beliefs regarding familial IBD risk and self-reported family diet changes, and support future research addressing balanced familial-risk communication for unaffected FDRs.