Research Papers: Breast CancerThe effect of NSAIDs exposure on breast cancer risk in female patients with autoimmune diseasesHung, Chih-Hsinga,,e,,f,,g,,l,,*; Lin, Yi-Chinga,,b,,e,,h,,*; Chang, Yu-Hanm; Lin, Yu-Chihc,,i; Huang, Hsin-Yim; Yeh, Wei-Jum; Wu, Ting-Yim; Hou, Ming-Fengd,,j,,kAuthor Information aDepartment of Pediatrics bDepartment of Laboratory Medicine cDepartment of Internal Medicine, Division of General Internal Medicine dDepartment of Surgery, Division of Breast Surgery, Kaohsiung Medical University Hospital eResearch Center for Environmental Medicine fGraduate Institute of Medicine gDepartment of Pediatrics hDepartment of Laboratory Medicine iDepartment of Medical Humanities and Education, School of Medicine jGraduate Institute of Clinical Medicine, College of Medicine, Kaohsiung Medical University kDepartment of Surgery lDepartment of Pediatrics mTeaching and Research Center,Kaohsiung Municipal Hsiao-Kang Hospital, Kaohsiung, Taiwan *Chih-Hsing Hung and Yi-Ching Lin contributed equally to the writing of this article Received 5 July 2018 Accepted 5 August 2018 Correspondence to Ming-Feng Hou, MD, Department of Surgery, Kaohsiung Medical University Hospital, 100, Shih-Chuan 1st Road, Kaohsiung 80756, Taiwan Tel: + 886 7312 1101/6507; fax: + 886 7321 3931; e-mail: [email protected] European Journal of Cancer Prevention: September 2019 - Volume 28 - Issue 5 - p 428-434 doi: 10.1097/CEJ.0000000000000476 Buy Metrics Abstract Both breast cancer and autoimmune diseases (ADs) are predominant in women. NSAIDs are common medications for AD. Evidence on the association between NSAIDs use and breast cancer risk is controversial. We investigated the association between NSAIDs exposure and breast cancer risk in female patients with AD. AD patients older than 18 years of age were enrolled from Taiwan Longitudinal Health Insurance Database 2005. The NSAID users were defined as AD patients who had ever taken NSAIDs for at least 3 months between 2000 and 2009. All individuals were followed from the date of first diagnosis of AD to the end of 2013 to evaluate the risk of breast cancer. We estimated the adjusted hazard ratio (HR) using Cox proportional hazard regression after adjusting for age, comorbidities and medications. A total of 12 331 NSAID users and 12 331 non-NSAID users were included in this study after 1: 1 individual matching. The NSAID users were less likely to develop breast cancer than the non-NSAID users (adjusted HR: 0.37; 95% confidence interval: 0.27–0.50; P < 0.001), even if they used NSAIDs with low cumulative defined daily doses (adjusted HR: 0.42; 95% confidence interval: 0.34–0.53; P < 0.001). The incidence of new-onset breast cancer in NSAID users was significantly decreased in users taking selective cyclooxygenase 2 inhibitors, diclofenac, ibuprofen and piroxicam. Lower cumulative hazard rates were found in the AD patients who used NSAIDs (P < 0.001). NSAID exposure is associated with a decreased risk of breast cancer in female AD patients. Copyright © 2018 Wolters Kluwer Health, Inc. All rights reserved.