Aspirin protects against gastric cancer: results of a case-control study from Moscow, Russia.

A case-control study of stomach cancer which includes 448 cases and 610 hospital controls has been conducted in Moscow, Russia. Information on life-style habits, such as smoking, alcohol consumption, diet, medical history and use of different medications including aspirin and other non-steroidal anti-inflammatory drugs (NSAIDs) was collected using a self-administered structured questionnaire. Venous blood was drawn from 361 cases and 441 controls. A serological test for Helicobacter pylori immunoglobulin G was performed to detect infected individuals. Use of aspirin and other NSAIDs was associated with protection against cancer of the stomach (OR = 0.60, 95% CI 0.41-0.90). Analysis by subsite revealed that aspirin did not affect the risk of cancer of the gastric cardia but had a protective effect for non-cardia gastric cancer. The OR associated with use of aspirin adjusted for age and education for both sexes combined was 0.49 (95% CI 0.31-0.77). A decrease in relative risk was statistically significant for men (OR = 0.48, 95% CI 0.25-0.92) and women (OR = 0.52, 95% CI 0.28-0.97). Controlling for major risk factors did not attenuate the reduction in risk. The observed associations were also present in individuals who were H. pylori immunoglobulin G-positive. There was no reduction in risk associated with aspirin and/or non-aspirin NSAIDs among non-infected subjects.