Association of Body Mass Index with Disorders of Gut-Brain Interaction: A Large Global Population-Based Analysis

OBJECTIVES: Individuals with underweight or obesity may have altered gut-brain signaling. This study investigated the association between body mass index (BMI) and the prevalence and burden of disorders of gut-brain interaction (DGBI). METHODS: This cross-sectional analysis utilized the internet-based data from the Rome Foundation Global Epidemiology Study, conducted in 2017-2018 across 26 countries. Adults aged ≥18 years with BMI data were included. DGBI were diagnosed according to the Rome IV criteria. Associations between BMI and DGBI were analyzed across BMI categories and for each 5 kg/m2 increment above 25 kg/m2 using mixed logistic regression models adjusted for age, sex, diabetes, psychological distress, and healthcare utilization. Additional analyses evaluated anatomical DGBI groups, overlapping disorders, and psychometric scales. RESULTS: Among 48,366 participants, the prevalence of DGBI followed a U-shaped pattern across BMI categories. After adjustment, underweight groups had similar odds of any DGBI compared with those with normal BMI, whereas the odds progressively increased for overweight and obesity groups (class I: 1.20; 95%CI 1.13-1.29; class II: 1.23; 95%CI 1.11-1.36; class III: 1.52; 95%CI 1.32-1.74). Every 5 kg/m2 BMI increase above 25 kg/m2 raised DGBI odds by 8% (95%CI 4%-11%). Associations were strongest for esophageal and gastroduodenal disorders. Higher BMI was associated with poorer physical and mental health and greater anxiety and depression, irrespective of the presence of DGBI. CONCLUSIONS: Higher, but not lower, BMI is independently associated with increased prevalence and symptom burden of DGBI. Obesity confers the highest odds for overlapping disorders and psychological disturbances, underscoring the importance of integrated metabolic and behavioral management strategies.