title: Effect of bedtime on recurrent aphthous stomatitis in college students.
abstract: OBJECTIVE
  In this study, we conducted a questionnaire-based survey at Sichuan University to investigate the potential effects of bedtime on recurrent aphthous stomatitis (RAS).
  
  
  METHODS
  An anonymous self-designed questionnaire was adopted to investigate the association between bedtime and RAS in college students at Sichuan University. Statistical analyses were used to identify risk factors for RAS and to explore the relationship between bedtime and RAS.
  
  
  RESULTS
  One thousand six students were investigated. High frequency of colds (odds ratio [OR] 2.17; 95% confidence interval [CI] 1.52-3.10; P < .001) and bedtime after 11 p.m. (OR 16.55; 95% CI 6.49-42.16; P < .001) were independent risk factors for RAS recurrence, but family history, stress, bad relationships with roommates, and gastrointestinal disease were not. Moreover, increased frequency of bedtime after 11 p.m. (τ > 0; P < .05), as well as longer cumulative time from 11 p.m. to bedtime (R > 0; P < .05), was correlated with increased severity of ulcers.
  
  
  CONCLUSIONS
  Bedtime after 11 p.m. not only served as an independent risk factor but both its frequency and cumulative time were also associated with severity of RAS in college students.
authors.affiliation: Undergraduate Student, West China School of Stomatology, Sichuan University.
authors.forename: Ruiyang
authors.initials: R
authors.lastname: Ma
authors.affiliation: Graduate Student, State Key Laboratory of Oral Diseases, Sichuan University.
authors.forename: Hong
authors.initials: H
authors.lastname: Chen
authors.affiliation: Undergraduate Student, West China School of Stomatology, Sichuan University.
authors.forename: Tengfei
authors.initials: T
authors.lastname: Zhou
authors.affiliation: Undergraduate Student, West China School of Stomatology, Sichuan University.
authors.forename: Xiyan
authors.initials: X
authors.lastname: Chen
authors.affiliation: Graduate Student, Department of Statistics, School of Mathematical Sciences, Sichuan University.
authors.forename: Chaoling
authors.initials: C
authors.lastname: Wang
authors.affiliation: Undergraduate Student, School of Computer Sciences, Sichuan University.
authors.forename: Yijin
authors.initials: Y
authors.lastname: Chen
authors.affiliation: Undergraduate Student, School of Mathematical Sciences, Sichuan University.
authors.forename: Songlin
authors.initials: S
authors.lastname: Rao
authors.affiliation: Associate Professor, Department of Oral medicine, West China School of Stomatology, Sichuan University.
authors.forename: Lin
authors.initials: L
authors.lastname: Ge
authors.affiliation: Professor, Department of Oral medicine, West China School of Stomatology, Sichuan University. Electronic address: Linmei2.k@163.com.
authors.forename: Mei
authors.initials: M
authors.lastname: Lin
mesh_terms: D002681:China; D002940:Circadian Rhythm; D005260:Female; D006801:Humans; D008297:Male; D012008:Recurrence; D012189:Retrospective Studies; D012307:Risk Factors; D012890:Sleep; D013281:Stomatitis, Aphthous / Q000209:etiology*; D013334:Students; D011795:Surveys and Questionnaires; D014495:Universities; D055815:Young Adult