Associations of alcohol use disorders with esophageal and gastric cancers: a population-based study in Sweden.

Alcohol consumption is associated with squamous cell carcinoma of the esophagus, but little is known about whether alcohol consumption is associated with adenocarcinoma of the esophagus and gastric cancer, which we attempt to clarify in this study. Individuals with alcohol use disorders were identified from the nation-wide Swedish Hospital Discharge Register and Outpatient Register, the Crime Register, and the Prescription Drug Register, and they were linked to the Swedish Cancer Registry to calculate standardized incidence ratios of esophageal and gastric cancers using those without alcohol use disorders (AUDs) as a reference. A total of 14 518 and 73 504 patients were diagnosed with esophageal and gastric cancers, separately, during the study period. The risk of esophageal cancer was significantly increased, with a standardized incidence ratio of 2.24 (95% confidence interval 2.08-2.41) among individuals with AUDs. Both squamous cell carcinoma and adenocarcinoma of the esophagus were increased (2.89 for squamous cell carcinoma and 1.20 for adenocarcinoma). The incidence of gastric cancer was significantly decreased and the decrease was even more prominant for corpus cancer compared with cardia cancer (0.57 vs. 0.82). In this retrospective cohort study, we found that AUDs were associated with an increased risk of both squamous cell carcinoma and adenocarcinoma of the esophagus, whereas individuals with AUDs had a lower risk of gastric cancer, especially for corpus cancer, which may be related to the eradication of Helicobacter pylori infection. However, the underlying mechanisms need to be explored in future studies.