title: Combined effects of obesity, acid reflux and smoking on the risk of adenocarcinomas of the oesophagus.
abstract: OBJECTIVE
  To measure the relative risks of adenocarcinomas of the oesophagus and gastro-oesophageal junction associated with measures of obesity, and their interactions with age, sex, gastro-oesophageal reflux symptoms and smoking.
  
  
  METHODS
  Population-based case-control study in Australia.
  
  
  METHODS
  Patients with adenocarcinomas of the oesophagus (n = 367) or gastro-oesophageal junction (n = 426) were compared with control participants (n = 1580) sampled from a population register.
  
  
  METHODS
  Relative risk of adenocarcinoma of the oesophagus or gastro-oesophageal junction.
  
  
  RESULTS
  Risks of oesophageal adenocarcinoma increased monotonically with body mass index (BMI) (p(trend) <0.001). Highest risks were seen for BMI >or=40 kg/m2 (odds ratio (OR) = 6.1, 95% CI 2.7 to 13.6) compared with "healthy" BMI (18.5-24.9 kg/m2). Adjustment for gastro-oesophageal reflux and other factors modestly attenuated risks. Risks associated with obesity were substantially higher among men (OR = 2.6, 95% CI 1.8 to 3.9) than women (OR = 1.4, 95% CI 0.5 to 3.5), and among those aged <50 years (OR = 7.5, 95% CI 1.7 to 33.0) than those aged >or=50 years (OR = 2.2, 95% CI 1.5 to 3.1). Obese people with frequent symptoms of gastro-oesophageal reflux had significantly higher risks (OR = 16.5, 95% CI 8.9 to 30.6) than people with obesity but no reflux (OR = 2.2, 95% CI 1.1 to 4.3) or reflux but no obesity (OR = 5.6, 95% 2.8 to 11.3), consistent with a synergistic interaction between these factors. Similar associations, but of smaller magnitude, were seen for gastro-oesophageal junction adenocarcinomas.
  
  
  CONCLUSIONS
  Obesity increases the risk of oesophageal adenocarcinoma independently of other factors, particularly among men. From a clinical perspective, these data suggest that patients with obesity and frequent symptoms of gastro-oesophageal reflux are at especially increased risk of adenocarcinoma.
authors.affiliation: Division of Population Studies and Human Genetics, Queensland Institute of Medical Research, PO Royal Brisbane Hospital, Queensland 4029, Australia. david.whiteman@qimr.edu.au
authors.forename: D C
authors.initials: DC
authors.lastname: Whiteman
authors.forename: S
authors.initials: S
authors.lastname: Sadeghi
authors.forename: N
authors.initials: N
authors.lastname: Pandeya
authors.forename: B M
authors.initials: BM
authors.lastname: Smithers
authors.forename: D C
authors.initials: DC
authors.lastname: Gotley
authors.forename: C J
authors.initials: CJ
authors.lastname: Bain
authors.forename: P M
authors.initials: PM
authors.lastname: Webb
authors.forename: A C
authors.initials: AC
authors.lastname: Green
mesh_terms: D000230:Adenocarcinoma / Q000209:etiology*; D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D015992:Body Mass Index; D016022:Case-Control Studies; D004938:Esophageal Neoplasms / Q000209:etiology*; D004943:Esophagogastric Junction; D005260:Female; D005764:Gastroesophageal Reflux / Q000150:complications*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000150:complications*; D012307:Risk Factors; D012737:Sex Factors; D012907:Smoking / Q000009:adverse effects*