Supplementary Material for: Family History as a Dominant Risk Factor for Uninvestigated Dyspepsia and Chronic Constipation: A Rome IV-Based Study among Japanese University Students

Background Uninvestigated dyspepsia (UD) and chronic constipation (CC) are common disorders of gut-brain interaction (DGBI). However, limited research has assessed their risk factors in young adults, particularly the influence of family history. This study investigated the associated factors for UD and CC, focusing on family history among Japanese university students. Methods A cross-sectional study was conducted at Hiroshima University. UD and CC were diagnosed using the Rome IV criteria. Multivariate logistic regression was performed to identify associated factors of UD and CC. Results Among 10,500 individuals participating in the annual health checkup, 7,496 responded to the web-based questionnaire, and 5,386 completed it. The mean age of the participants was 21.1 ± 4.1 years, with a male-to-female ratio of 1:1.17. The prevalence of UD and CC was 7.3% and 13.7%, respectively. Family history was associated with both UD (odds ratio [OR]: 4.29; 95% confidence interval [CI]: 3.17-5.79) and CC (OR: 2.77; 95% CI: 2.31-3.31). Depression and physical inactivity were shared associated factors. Alcohol consumption (OR = 2.36; 95% CI: 1.15-4.83) and smoking (OR = 1.59; 95% CI: 1.02-2.49) were identified as associated factors for UD, while female sex (OR = 2.00; 95% CI: 1.69-2.36) and short sleep duration (OR = 1.28; 95% CI: 1.09-1.50) were associated with CC. Conclusions Family history was found to be a predominant factor associated with both UD and CC, with a relatively stronger association for UD. Our finding highlights the need to consider familial factors in future prevention and intervention strategies for UD and CC in young adults.