Education status and household income in relation to constipation prevalence in Japanese patients with ulcerative colitis Running title: Socioeconomic status and constipation in UC

Abstract Background Constipation frequently occurs in patients with ulcerative colitis (UC). Although socioeconomic status has been linked to constipation in the general population, limited data are available regarding this association among individuals with UC. The present study investigated the relationship between educational attainment, household income, and the prevalence of constipation in Japanese patients with UC. Methods A total of 289 patients with UC were enrolled. Constipation was defined according to the Rome I criteria and/or current use of laxative medications. Educational attainment and household income were categorized into three levels using a self-administered questionnaire. Endoscopic remission was defined as a Mayo endoscopic subscore (MES) of 0. Clinical remission (CR) was defined as the absence of rectal bleeding and a normal stool frequency of fewer than three bowel movements per day. Results Constipation was identified in 11.8% of participants. The proportion of patients with constipation decreased across increasing educational levels (low: 29.6%; middle: 10.9%; high: 7.6%). After adjustment for potential confounders, lower educational attainment remained significantly associated with constipation (adjusted odds ratio [OR]: 4.00 [95% confidence interval (CI): 1.15–14.5], p for trend = 0.044). In contrast, no statistically significant association was observed between household income and constipation. Conclusion In this cohort of Japanese patients with UC, lower educational attainment was independently associated with a higher prevalence of constipation, whereas household income showed no significant relationship with constipation.