title: A prospective cohort study of obesity and risk of oesophageal and gastric adenocarcinoma in the NIH-AARP Diet and Health Study.
abstract: OBJECTIVE
  The incidence of oesophageal adenocarcinoma (EAC) has increased rapidly over the past 40 years and accumulating evidence suggests that obesity, as measured by body mass index (BMI), is a major risk factor. It remains unclear whether abdominal obesity is associated with EAC and gastric adenocarcinoma.
  
  
  METHODS
  Cox proportional hazards regression was used to examine associations between overall and abdominal obesity with EAC and gastric adenocarcinoma among 218 854 participants in the prospective NIH-AARP cohort.
  
  
  RESULTS
  253 incident EAC, 191 gastric cardia adenocarcinomas and 125 gastric non-cardia adenocarcinomas accrued to the cohort. Overall obesity (BMI) was positively associated with EAC and gastric cardia adenocarcinoma risk (highest (≥35 kg/m(2)) vs referent (18.5-<25 kg/m(2)); HR 2.11, 95% CI 1.09 to 4.09 and HR 3.67, 95% CI 2.00 to 6.71, respectively). Waist circumference was also positively associated with EAC and gastric cardia adenocarcinoma risk (highest vs referent; HR 2.01, 95% CI 1.35 to 3.00 and HR 2.22, 95% CI 1.43 to 3.47, respectively), whereas waist-to-hip ratio (WHR) was positively associated with EAC risk only (highest vs referent; HR 1.81, 95% CI 1.24 to 2.64) and persisted in patients with normal BMI (18.5-<25 kg/m(2)). Mutual adjustment of WHR and BMI attenuated both, but did not eliminate the positive associations for either with risk of EAC. In contrast, the majority of the anthropometric variables were not associated with adenocarcinomas of the gastric non-cardia.
  
  
  CONCLUSIONS
  Overall obesity was associated with a higher risk of EAC and gastric cardia adenocarcinoma, whereas abdominal obesity was found to be associated with increased EAC risk; even in people with normal BMI.
authors.affiliation: Cancer Epidemiology Health Services Research Group, Centre for Public Health, Queens University Belfast, Belfast, Northern Ireland, UK. m.odoherty@qub.ac.uk
authors.forename: Mark G
authors.initials: MG
authors.lastname: O'Doherty
authors.forename: Neal D
authors.initials: ND
authors.lastname: Freedman
authors.forename: Albert R
authors.initials: AR
authors.lastname: Hollenbeck
authors.forename: Arthur
authors.initials: A
authors.lastname: Schatzkin
authors.forename: Christian C
authors.initials: CC
authors.lastname: Abnet
mesh_terms: D000230:Adenocarcinoma / Q000453:epidemiology* / Q000209:etiology; D000368:Aged; D015992:Body Mass Index; D015331:Cohort Studies; D004938:Esophageal Neoplasms / Q000453:epidemiology* / Q000209:etiology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D009316:National Institutes of Health (U.S.); D056128:Obesity, Abdominal / Q000150:complications*; D016016:Proportional Hazards Models; D011446:Prospective Studies; D012307:Risk Factors; D013274:Stomach Neoplasms / Q000453:epidemiology* / Q000209:etiology; D011795:Surveys and Questionnaires; D014481:United States; D055105:Waist Circumference; D049629:Waist-Hip Ratio