title: Helicobacter pylori infection in dental professionals: a 6-year prospective study.
abstract: BACKGROUND
  In a previous cross-sectional study, we reported no significant differences between dentists and controls in the seroprevalence of Helicobacter pylori. The aim of the present study is to determine the risk and the risk factors for new infection of H. pylori. This is the first report designed to assess the seroprevalence of H. pylori infection over a 6-year period in a cohort of dental professionals.
  
  
  METHODS
  We collected blood samples from employees of Kanagawa Dental College to test for serum anti-H. pylori IgG. We collected 566 samples in 1997 and another 551 samples in 2003. Questionnaires completed by participants provided information about risk factors of H. pylori infection.
  
  
  RESULTS
  A total of 236 employees were tested on both occasions. Of the 170 who were seronegative in 1997, we randomly selected 59 from among the dental professionals (dentists and dental nurses). As controls, we selected 59 from among the nonclinical staff who were matched for sex and age. The risk of new infection of H. pylori for dental professionals is 1.12%/year and the relative risk is 4.0. We determined the risk factors for acquiring H. pylori using logistic regression. Adjusted odds ratio being a dental professionals was 2.68 (95% confidence interval [CI]: 0.55-19.67), having upper gastrointestinal family history was 4.84 (95% CI: 0.83-26.72), and age over 40 was 8.83 (95% CI: 1.36-177.24).
  
  
  CONCLUSIONS
  This 6-year prospective study shows that dental professionals are at greater risk of being infected by H. pylori than are controls.
authors.affiliation: Department of Internal Medicine II, Yokohama City University, School of Medicine, 3-9 Fukuura, Kanazawa-ku, Yokohama, 236-0004 Japan.
authors.forename: Reikei
authors.initials: R
authors.lastname: Matsuda
authors.forename: Toshio
authors.initials: T
authors.lastname: Morizane
mesh_terms: D000328:Adult; D000907:Antibodies, Bacterial / Q000097:blood*; D015331:Cohort Studies; D003727:Dental Auxiliaries; D003815:Dentists; D005260:Female; D016481:Helicobacter Infections / Q000453:epidemiology* / Q000382:microbiology; D016480:Helicobacter pylori / Q000276:immunology*; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood; D008297:Male; D011446:Prospective Studies; D012307:Risk Factors; D016036:Seroepidemiologic Studies
chemical_list: D000907:Antibodies, Bacterial; D007074:Immunoglobulin G