Antacid drug use and risk of esophageal and gastric adenocarcinomas in Los Angeles County.

OBJECTIVES Concern has been expressed that antacid drugs increase the risk of esophageal and gastric adenocarcinomas. METHODS This population-based case-control study recruited patients with incident esophageal adenocarcinoma (n = 220), gastric cardiac adenocarcinoma (n = 277), or distal gastric adenocarcinoma (n = 441) diagnosed between 1992 and 1997, and 1,356 control participants in Los Angeles County. Unconditional polychotomous multivariable logistic regression analyses were done to evaluate the association between antacid drug use and these cancers. RESULTS Among participants who took nonprescription acid neutralizing agents for >3 years, the odds ratio for esophageal adenocarcinoma was 6.32 compared with never users (95% confidence interval, 3.14-12.69; P(trend) < 0.01). Analyses stratified by history of physician diagnosed upper gastrointestinal (UGI) disorders revealed a greater increase in esophageal adenocarcinoma risk associated with nonprescription antacid use among persons with no UGI disorder than among those with an UGI disorder (homogeneity of trends P = 0.07). Regular use of nonprescription acid neutralizing agents was not associated with risk of adenocarcinomas of the gastric cardia or distal stomach. Regular use of prescription acid suppressive drugs was not associated with risk for any of these cancers. CONCLUSION We found risk of esophageal adenocarcinoma was greater among long-term nonprescription acid neutralizing drugs in participants without physician-diagnosed UGI conditions than among those with these conditions; this may represent self medication for undiagnosed precursor conditions or it may be that nonprescription acid neutralizing drugs, taken without limitation on amount used when symptoms are most intense, may permit alkaline bile reflux into the lower esophagus, thereby increasing esophageal adenocarcinoma risk.