title: Long-term use of tamoxifen reduces the risk of dementia: a nationwide population-based cohort study.
abstract: BACKGROUND
  To assess the possible association between tamoxifen treatment and the subsequent risk of dementia in patients with breast cancer, a population-based cohort study was conducted using the Taiwanese National Health Insurance Research Database.
  
  
  METHODS
  The study cohort contained 24 197 patients diagnosed with breast cancer between 1 January 2000 and 31 December 2004. Among them, 16 556 cases received tamoxifen treatment and 7641 did not. Four women without breast cancer were frequency matched to each case by age and index-year as the cancer-free group. The outcome of the analysis of is dementia. Hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated using multivariate Cox proportional hazards regression models.
  
  
  RESULTS
  Patients with breast cancer exhibited a similar risk of developing dementia (adjusted HR = 0.95, 95% CI = 0.86-1.04) compared with the cancer-free group. In addition, among women diagnosed with breast cancer, tamoxifen users exhibited a significant 17% lower risk of dementia compared with those not using tamoxifen (adjusted HR = 0.83, 95% CI = 0.69-0.98), but the significant difference was limited to 5 years or more use (adjusted HR = 0.47, 95% CI = 0.32-0.69). Both tamoxifen and aromatase inhibitor use had a joint effect, with a significantly lower risk of dementia among patients.
  
  
  CONCLUSIONS
  The results of this population-based cohort study suggest that long-term use of tamoxifen in patients with breast cancer is associated with a lower risk of dementia.
authors: From the Department of Radiation Oncology, Zuoying Branch of Kaohsiung Armed Forces General Hospital, Kaohsiung, Taiwan.
authors: L-M
authors: LM
authors: Sun
authors: Management Office for Health Data, China Medical University Hospital, Taichung, Taiwan.
authors: H-J
authors: HJ
authors: Chen
authors: Department of Radiation Oncology, China Medical University Hospital, Taichung, Taiwan, Graduate Institute of Clinical Medical Science and School of Medicine, College of Medicine, China Medical University, Taichung, Taiwan and.
authors: J-A
authors: JA
authors: Liang
authors: Graduate Institute of Clinical Medical Science and School of Medicine, College of Medicine, China Medical University, Taichung, Taiwan and Department of Nuclear Medicine and PET Center, China Medical University Hospital, Taichung, Taiwan d10040@mail.cmuh.org.tw.
authors: C-H
authors: CH
authors: Kao
mesh_terms: D000328:Adult; D018931:Antineoplastic Agents, Hormonal / Q000627:therapeutic use; D001943:Breast Neoplasms / Q000188:drug therapy / Q000453:epidemiology; D015331:Cohort Studies; D003704:Dementia / Q000175:diagnosis / Q000453:epidemiology; D005260:Female; D006801:Humans; D008875:Middle Aged; D016016:Proportional Hazards Models; D065840:Protective Factors; D013624:Taiwan / Q000453:epidemiology; D013629:Tamoxifen / Q000627:therapeutic use*
chemical_list: D018931:Antineoplastic Agents, Hormonal; D013629:Tamoxifen