Oral disease and risk of oesophageal and gastric cancer in a nationwide nested case-control study in Sweden.

The association between the exposure to oral disease and the outcomes of oesophageal and gastric cancer was examined in a Swedish nationwide inpatient register-based nested case-control study in 1964-2008. The study included 6,156 oesophageal squamous-cell carcinoma cases that were compared with 29,993 controls, 2684 oesophageal adenocarcinoma cases that were compared with 15,036 controls and 38,308 gastric cancer cases that were compared with 99,991 controls. For oesophageal squamous cell carcinoma, the age and sex adjusted odds ratio (OR) among patients with a history of oral disease was 1.3 (95% confidence interval (95% CI): 0.9,-1.9), and 1.1 (95% CI 0.8,-1.7) after adjustment for diseases related to alcohol consumption or tobacco smoking. For oesophageal adenocarcinoma, the age and sex adjusted OR was increased (OR 1.7, 95% CI 1.1-2.6), and remained increased (OR 1.6, 95% CI 1.0-2.4) after adjustment for diseases related to smoking or alcohol consumption, gastroesophageal reflux, obesity and ulcer disease. For gastric cancer, no statistically significantly increased risk was observed (age and sex adjusted OR 0.9, 95% CI 0.7-1.1, and fully adjusted OR 0.9, 95% CI 0.7-1.1). In conclusion, this study supports the hypothesis that oral disease increases the risk of oesophageal adenocarcinoma, but not for oesophageal squamous cell carcinoma or gastric cancer. Further investigations are warranted.