Practice of Epidemiology Population Attributable Fractions of Adenocarcinoma of the Esophagus and Gastroesophageal Junction

Obesity, gastroesophageal reflux, and smoking have repeatedly been shown to be important and independent risk factors for adenocarcinoma of the esophagus (EAC) and of the gastroesophageal junction (GEJAC). There have been few attempts, however, to quantify the proportion of disease associated with these potentially modifiable factors. The authors have estimated the population attributable fraction of EAC and GEJAC attributable to obesity, symptoms of gastroesophageal reflux, and smoking using data from a population-based case-control study conducted in Australia between 2002 and 2005. Cases were patients with EAC (n1⁄4 364) or GEJAC (n1⁄4 425). Controls (n1⁄4 1,580) were randomly sampled from a population register. Combinations of smoking, body mass index (weight in kilograms divided by height in meters squared), and gastroesophageal reflux together accounted for 76% (95% confidence interval: 66, 84) of EAC cases and 69% (95% confidence interval: 58, 78) of GEJAC cases. Individually, high body mass index ( 30) and frequent acid reflux ( 1 time/week) accounted for the greatest proportions of EAC (23% and 36%, respectively), and smoking and frequent symptoms of acid reflux accounted for the greatest proportions of GEJAC (43% and 28%, respectively). The present study suggests that these cancers may be largely prevented by maintaining healthy body mass index, avoiding smoking, and controlling symptomatic gastroesophageal reflux.