title: Daytime Sleepiness, Circadian Preference, Caffeine Consumption and Khat Use among College Students in Ethiopia.
abstract: OBJECTIVE
  To estimate the prevalence of daytime sleepiness and circadian preferences, and to examine the extent to which caffeine consumption and Khat (a herbal stimulant) use are associated with daytime sleepiness and evening chronotype among Ethiopian college students.
  
  
  METHODS
  A cross-sectional study was conducted among 2,410 college students. A self-administered questionnaire was used to collect information about sleep, behavioral risk factors such as caffeinated beverages, tobacco, alcohol, and Khat consumption. Daytime sleepiness and chronotype were assessed using the Epworth Sleepiness Scale (ESS) and the Horne & Ostberg Morningness /Eveningness Questionnaire (MEQ), respectively. Linear and logistic regression models were used to evaluate associations.
  
  
  RESULTS
  Daytime sleepiness (ESS≥10) was present in 26% of the students (95% CI: 24.4-27.8%) with 25.9% in males and 25.5% in females. A total of 30 (0.8%) students were classified as evening chronotypes (0.7% in females and 0.9% in males). Overall, Overall, Khat consumption, excessive alcohol use and cigarette smoking status were associated with evening chronotype. Use of any caffeinated beverages (OR=2.18; 95%CI: 0.82-5.77) and Khat consumption (OR=7.43; 95%CI: 3.28-16.98) increased the odds of evening chronotype.
  
  
  CONCLUSIONS
  The prevalence of daytime sleepiness among our study population was high while few were classified as evening chronotypes. We also found increased odds of evening chronotype with caffeine consumption and Khat use amongst Ethiopian college students. Prospective cohort studies that examine the effects of caffeinated beverages and Khat use on sleep disorders among young adults are needed.
authors.affiliation: Department of Epidemiology, Multidisciplinary Health International Research Training Program, Harvard School of Public Health, Boston, Massachusetts, USA.
authors.forename: Darve
authors.initials: D
authors.lastname: Robinson
authors.affiliation: Department of Epidemiology, Multidisciplinary Health International Research Training Program, Harvard School of Public Health, Boston, Massachusetts, USA.
authors.forename: Bizu
authors.initials: B
authors.lastname: Gelaye
authors.affiliation: Department of Epidemiology, Multidisciplinary Health International Research Training Program, Harvard School of Public Health, Boston, Massachusetts, USA ; Department of Mathematics & Statistics, Georgetown University, Washington, DC.
authors.forename: Mahlet G
authors.initials: MG
authors.lastname: Tadesse
authors.affiliation: Department of Epidemiology, Multidisciplinary Health International Research Training Program, Harvard School of Public Health, Boston, Massachusetts, USA.
authors.forename: Michelle A
authors.initials: MA
authors.lastname: Williams
authors.affiliation: Addis Continental Institute of Public Health, Addis Ababa, Ethiopia.
authors.forename: Seblewengel
authors.initials: S
authors.lastname: Lemma
authors.affiliation: Addis Continental Institute of Public Health, Addis Ababa, Ethiopia.
authors.forename: Yemane
authors.initials: Y
authors.lastname: Berhane