title: Khat chewing is a risk factor of duodenal ulcer.
authors.forename: Y A
authors.initials: YA
authors.lastname: Raja'a
authors.forename: T A
authors.initials: TA
authors.lastname: Noman
authors.forename: A K
authors.initials: AK
authors.lastname: al Warafi
authors.forename: N A
authors.initials: NA
authors.lastname: al Mashraki
authors.forename: A M
authors.initials: AM
authors.lastname: al Yosofi
mesh_terms: D016022:Case-Control Studies; D029754:Catha / Q000009:adverse effects*; D015986:Confounding Factors, Epidemiologic; D004381:Duodenal Ulcer / Q000453:epidemiology / Q000209:etiology*; D005260:Female; D016481:Helicobacter Infections / Q000150:complications; D016480:Helicobacter pylori; D006801:Humans; D008297:Male; D012307:Risk Factors; D019966:Substance-Related Disorders / Q000150:complications*; D011795:Surveys and Questionnaires; D015006:Yemen / Q000453:epidemiology