title: No association between gastroesophageal reflux and cancers of the larynx and pharynx.
abstract: OBJECTIVE
  To examine the proposed relation between gastroesophageal reflux disease and cancers of the larynx and pharynx.
  
  
  METHODS
  A cohort of 66,965 patients with discharge diagnoses of heartburn, hiatal hernia, or esophagitis was identified in the Swedish Inpatient Register. We observed a total of 376,622 person-years in the cohort. Identification of laryngeal and pharyngeal cancers was achieved through the Swedish Cancer Register. Standardized incidence ratios, the ratio of the observed to the expected number of cancers, derived from the general Swedish population and adjusted for sex, age, and calendar year, was used to estimate the relative risk.
  
  
  RESULTS
  During follow-up, 30 cases of laryngeal and 31 cases of pharyngeal cancer were detected in the cohort. Slightly increased risks of laryngeal [relative risk, 1.6; 95% confidence interval (CI), 1.1-2.2] and pharyngeal carcinomas (relative risk, 1.9; 95% CI, 1.3-2.8) were observed in the total reflux cohort. After stratification to exclude cohort members with a diagnosis of alcoholism, no significant increase in the risk of laryngeal (relative risk, 1.3; 95% CI, 0.8-2.0) or pharyngeal carcinomas (relative risk, 1.0; 95% CI, 0.5-1.6) was found compared with the general population. Furthermore, there were no dose-response patterns of the risk for laryngeal and pharyngeal cancers with years of cohort follow-up, indicators of reflux severity, or specificity of reflux diagnosis.
  
  
  CONCLUSIONS
  This study provides no evidence in support of the proposed association between gastroesophageal reflux disease and cancers of the larynx or pharynx.
authors.affiliation: Department of Surgery P9:03, Karolinska Hospital, SE-171 76 Stockholm, Sweden. magnus.nilsson@meb.ki.se
authors.forename: Magnus
authors.initials: M
authors.lastname: Nilsson
authors.forename: Wong-Ho
authors.initials: WH
authors.lastname: Chow
authors.forename: Mats
authors.initials: M
authors.lastname: Lindblad
authors.forename: Weimin
authors.initials: W
authors.lastname: Ye
mesh_terms: D000328:Adult; D000368:Aged; D000437:Alcoholism / Q000175:diagnosis / Q000453:epidemiology; D015331:Cohort Studies; D004941:Esophagitis / Q000175:diagnosis / Q000453:epidemiology; D005260:Female; D005764:Gastroesophageal Reflux / Q000150:complications* / Q000453:epidemiology; D006356:Heartburn / Q000175:diagnosis / Q000453:epidemiology; D006551:Hernia, Hiatal / Q000175:diagnosis / Q000453:epidemiology; D006760:Hospitalization; D006801:Humans; D007822:Laryngeal Neoplasms / Q000453:epidemiology* / Q000209:etiology*; D008297:Male; D008875:Middle Aged; D010610:Pharyngeal Neoplasms / Q000453:epidemiology* / Q000209:etiology*; D012042:Registries; D018570:Risk Assessment; D012307:Risk Factors; D013548:Sweden / Q000453:epidemiology