Passive Smoking Is Associated with the Risk of Functional Bowel Disorders Among College Freshmen

<b>Background</b>: Functional bowel disorders (FBDs) have detrimental effects on young adults, but the risk factors were not fully explored. This study aimed to investigate the prevalence and potential risk factors of FBDs in college freshmen, including, in particular, the association between passive smoking and the risk and symptoms of FBDs. <b>Methods</b>: A cross-sectional study was conducted in September 2019 in freshmen of Huazhong University of Science and Technology with a random cluster sampling method. Validated questionnaires were voluntarily completed by participants. Rome IV criteria were applied for the diagnosis of FBDs. Univariate analysis and multivariate logistic regression analysis (Model 1: unadjusted; Model 2: adjusted for age and sex; Model 3: adjusted for age, sex, intake frequency of coffee and juice, regular exercise, total sedentary time, sleep quality, interpersonal relationship, and SLSI scores) were performed to determine the potential risk factors of FBDs. <b>Results</b>: A total of 3074 participants were included in this study, among whom 236 college freshmen were diagnosed with FBDs. There was a positive relationship between passive smoking and the risk of FBDs (crude odds ratio [OR] = 2.084, 95% confidence interval [CI]: 1.480, 2.936, Model 1; adjusted OR = 1.825, 95%CI: 1.245, 2.675, Model 3). Moreover, the symptoms of hard stool, exertion, and sensation of obstruction in defecation were more frequent in passive smokers than non-passive smokers among FBD patients. Meanwhile, diarrhea was comparable between passive smokers and non-passive smokers among FBD patients. <b>Conclusions</b>: In the present study, around 7.68% of college freshmen were found to have FBDs. Passive smoking was positively associated with the risk of FBDs. Furthermore, passive smoking was significantly associated with constipation-related symptoms rather than diarrhea among FBD patients.