The Inverted U-shaped Curvilinear Relationship Between Conscientiousness and the Quality of Life in Patients with Irritable Bowel Syndrome

Background: Irritable bowel syndrome (IBS) is a functional gastrointestinal disorder that greatly affects the quality of life. While prior research suggested a linear connection between conscientiousness and health outcomes like quality of life, recent studies propose a more intricate, curved relationship. Objectives: The present study aimed to determine the inverted U-shaped curvilinear relationship between conscientiousness and quality of life in patients with irritable bowel syndrome. Methods: This descriptive-correlational study in Tehran s private gastroenterology clinic in 2020 included 232 IBS patients. Data collected via the NEO Five-Factor Inventory (NEO-FFI) and Irritable Bowel Syndrome Quality of Life (IBS-QOL) questionnaire were analyzed using SPSS version 26 and Excel 2023 for statistical assessment at a 95% confidence interval. Results: Scatter plots and regression equations demonstrated a strong curvilinear relationship (R 2= 0.14) between conscientiousness and IBS patients quality of life, surpassing the linear relationship (R 2= 0.08). Curvilinear regression analysis revealed significant correlations (95% CI) for both the first-degree coefficient (β1 = 2.304, P 0.001) and the second-degree coefficient (β2 = -2.043, P 0.001). Conclusions: The findings indicate an inverted U-shaped relationship between conscientiousness and quality of life in IBS individuals. This underscores the importance of addressing exceptionally high conscientiousness levels in healthcare.