Abstract Background and Aim Upper gastrointestinal symptoms (UGSs), including reflux and dyspeptic symptoms (postprandial distress syndrome [PDS] and epigastric pain syndrome [EPS]), affect health‐related quality of life. However, the influence of sex on the relationship between body mass index (BMI) and UGSs remains controversial. This study investigates the influence of sex on this association in healthy subjects. Methods and Results We utilized the database of a prospective, multicenter, cohort study of 7112 subjects who underwent upper endoscopy for health screening. A multivariable logistic regression analysis was conducted to assess the association between BMI and UGSs stratified by sex, adjusting for clinical features. The influence of sex on the association between the overlapping of UGSs and BMI in symptomatic subjects was also investigated. Reflux symptoms were significantly associated with high BMI (multivariable odds ratio [OR] 1.36; 95% confidence interval [CI] 1.10–1.67, P = 0.004). PDS symptoms were significantly associated with low BMI (OR 2.37; 95% CI 1.70–3.25; P < 0.0001), but EPS symptoms were not associated with BMI. The association between reflux symptoms and higher BMI was limited to men (men: OR 1.40; 95% CI 1.10–1.77; P = 0.005, women: P = 0.40). sex did not influence the association between the presence of PDS symptoms and lower BMI. The percentage of overlapping of all three symptoms (reflux, PDS, and EPS) was higher in women than in men (19.9% [58/292] vs 10.5% [49/468], P = 0.0002). Conclusions The influence of BMI on the presence of UGSs was significantly different according to sex in this large‐scale cohort.
