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.
Design and setting: Population-based case-control study in Australia
Patients: Patients with adenocarcinomas of the oesophagus (n=367) or gastro-oesophageal junction (n=426) were compared with control participants sampled from a population register (n=1,580).
Main outcome measure: Relative risk of adenocarcinoma of the oesophagus or gastro-oesophageal junction.
Results: Risks of oesophageal adenocarcinoma increased monotonically with body mass index (BMI) (ptrend <0.001). Highest risks were observed for BMI >40 kg/m2 (OR 6.1, 95%CI 2.7-13.6) 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 males (OR 2.6, 95%CI 1.8-3.9) than females (OR 1.4, 95% CI 0.5-3.5), and among those <50 years (OR 7.5, 95%CI 1.7-33.0) than >50 years (OR 2.2, 95% CI 1.5-3.1). Obese people with frequent symptoms of gastro-oesophageal reflux had significantly higher risks (OR 16.5, 95% CI 8.9-30.6) than people with obesity but no reflux (OR 2.2, 95%CI 1.1-4.3) or reflux but no obesity (OR 5.6, 95% 2.8-11.3), consistent with a synergistic interaction between these factors. Similar associations, but of lower magnitude, were observed for gastro-oesophageal junction adenocarcinomas.
Conclusions: Obesity increases the risk of oesophageal adenocarcinoma independently of other factors, particularly among males. From a clinical perspective, these data suggest that patients with obesity and frequent symptoms of gastro-oesophageal reflux are at especially elevated risk of adenocarcinoma.
- case-control study
- gastro-oesophageal reflux