title: Prospective study of tooth loss and incident esophageal and gastric cancers in China.
abstract: OBJECTIVE
  To determine the association between tooth loss and the risk of developing esophageal squamous cell carcinoma, gastric cardia adenocarcinoma, or gastric non-cardia adenocarcinoma in a prospective study.
  
  
  METHODS
  Cox proportional hazards regression was used to examine these associations in a 28,868-person cohort followed prospectively for 5.25 years. The baseline questionnaire included questions regarding tooth loss, and individuals reporting lost teeth had their teeth counted by study personnel. The analytic cohort included 620 esophagus, 431 gastric cardia, and 102 gastric non-cardia cancer cases.
  
  
  RESULTS
  Tooth loss was associated with a significantly elevated risk of developing all three cancers. When examined as median splits, tooth loss was associated with a relative risk (RR) (95% confidence interval, CI) of 1.3 (1.1-1.6) in the esophagus, 1.3 (1.0-1.6) in the gastric cardia, and 1.8 (1.1-3.0) in the gastric non-cardia. Further analysis demonstrated that this increased risk was most strongly associated with the loss of the first few teeth and was primarily confined to the younger members of our cohort.
  
  
  CONCLUSIONS
  In this cohort tooth loss increased the risk of developing upper gastrointestinal cancer. We hypothesize that this may be related to alterations in oral bacterial flora and subsequent increases in the in-vivo production of carcinogens such as nitrosamines.
authors.affiliation: Cancer Prevention Studies Branch, Division of Clinical Sciences, National Cancer Institute, Bethesda, MD 20892-7058, USA. abnetc@mail.nih.gov
authors.forename: C C
authors.initials: CC
authors.lastname: Abnet
authors.forename: Y L
authors.initials: YL
authors.lastname: Qiao
authors.forename: S D
authors.initials: SD
authors.lastname: Mark
authors.forename: Z W
authors.initials: ZW
authors.lastname: Dong
authors.forename: P R
authors.initials: PR
authors.lastname: Taylor
authors.forename: S M
authors.initials: SM
authors.lastname: Dawsey
mesh_terms: D000230:Adenocarcinoma / Q000453:epidemiology*; D000328:Adult; D000368:Aged; D002294:Carcinoma, Squamous Cell / Q000453:epidemiology*; D002681:China / Q000453:epidemiology; D015331:Cohort Studies; D004938:Esophageal Neoplasms / Q000453:epidemiology*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012306:Risk; D013274:Stomach Neoplasms / Q000453:epidemiology*; D013997:Time Factors; D016388:Tooth Loss / Q000453:epidemiology*