KMAN Publication Inc. (KMANPUB) Health Nexus 4 Serial Number 14 2026 06 01 Structural Modeling of Functional Disability Severity Based on Health-Promoting Lifestyle and Distress Tolerance: The Mediating Role of Ego Strength in Patients with Functional Gastrointestinal Disorders Structural Modeling of Functional Disability Severity Based on Health-Promoting Lifestyle and Distress Tolerance: The Mediating Role of Ego Strength in Patients with Functional Gastrointestinal Disorders 1 15 EN Journal Article 2026 02 09 <p>Functional gastrointestinal disorders are common, multifactorial conditions that, in addition to biological dimensions, are influenced by psychological and lifestyle factors. Therefore, examining individual and psychological factors associated with the severity of functional disability in these patients can play an important role in achieving a better understanding of these disorders and designing effective interventions. The present study aimed to examine the fit of a structural model of functional disability severity based on health-promoting lifestyle and distress tolerance, with the mediating role of ego strength, in patients with functional gastrointestinal disorders. This applied study employed a correlational design using structural equation modeling. The statistical population consisted of patients with functional gastrointestinal disorders in Tehran, from whom 350 participants were selected through convenience sampling. Data were collected using the World Health Organization Disability Assessment Schedule (2000), the Health-Promoting Lifestyle Profile developed by Walker et al. (1995), the Distress Tolerance Scale developed by Simons and Gaher (2005), and the Ego Strength Scale developed by Markstrom et al. (1997). Data were analyzed using SPSS version 27 and AMOS version 26. The structural equation modeling results indicated that the proposed model demonstrated an acceptable fit. The model fit indices were χ²/df = 1.71, RMSEA = 0.06, CFI = 0.94, NFI = 0.93, GFI = 0.94, and AGFI = 0.93, all of which indicated an adequate fit of the model to the data. Overall, the findings demonstrated that health-promoting lifestyle and distress tolerance, through the mediating role of ego strength, play important roles in explaining the severity of functional disability among patients with functional gastrointestinal disorders.</p> https://www.journals.kmanpub.com/index.php/Health-Nexus/article/download/5948/11407