Recently, studies have reported that aspirin has chemopreventive properties. In this study, we used the Taiwan NHI database, which covers a population of 23 million (99.99%) Taiwanese from 2001 to 2011. This was a case–control study which identified 601,733 patients using ICD-9-CM codes who were diagnosed with cancer. Each case with 4 eligible controls was matched for age, sex, and index date and adjusted for confounding factors. The observed overall cancer risk (adjusted OR (AOR), 0.95; 95% CI 0.94 to 0.96) reduced with aspirin use, specifically, colorectal (AOR, 0.97; 95% CI 0.94 to 0.99) and digestive system (AOR, 0.96; 95% CI 0.94 to 0.98) cancers. Findings from the Asian population would contribute to the discussion on aspirin's safety profile.
Contributors Y-CL, UI, and H-CY designed the study, enrolled patients, interpreted data, wrote the report, and approved the final draft. UI, H-CY, and W-SJ designed the study, searched the published work, analyzed and interpreted data, reviewed the manuscript, and approved the final draft. Y-CL, W-SJ, and YY interpreted data, reviewed the report, and approved the final draft.
Funding This research is sponsored in part by Ministry of Science and Technology (MOST) under grant MOST 104-2221-E-038–013, MOST 104–3011-E-038-001, Health and welfare surcharge of tobacco products grant MOHW105-TDU-B-212-134001, and Ministry of Education, Taiwan, under grant TMUTOP103006-6.
Competing interests None declared.
Ethics approval Ethical approval was not required as we used anonymous data.
Provenance and peer review Not commissioned; externally peer reviewed.