title: Association of tamoxifen use and increased diabetes among Asian women diagnosed with breast cancer.
abstract: BACKGROUND
  We conducted a population-based cohort study to assess whether tamoxifen treatment is associated with an increased incidence of diabetes.
  
  
  METHODS
  Data obtained from the Taiwanese National Health Insurance Research Database were used for a population-based cohort study. The study cohort included 22 257 breast cancer patients diagnosed between 1 January 2000 and 31 December 2004. Among them, 15 210 cases received tamoxifen treatment and 7047 did not. Four subjects without breast cancer were frequency-matched by age and index year as the control group. Hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated using multivariate Cox proportional hazards regression analysis.
  
  
  RESULTS
  Breast cancer patients exhibited a 14% higher rate of developing diabetes (adjusted HR=1.14, 95% CI=1.08-1.20) compared with non-breast cancer controls, but the significant difference was limited to tamoxifen users. In addition, tamoxifen users exhibited a significantly increased risk of diabetes compared with non-tamoxifen users among women diagnosed with breast cancer (adjusted HR=1.31, 95% CI=1.19-1.45). Stratification by age groups indicated that both younger and older women diagnosed with breast cancer exhibited a significantly higher risk of diabetes than the normal control subjects did, and tamoxifen users consistently exhibited a significantly higher diabetes risk than non-tamoxifen users or normal control subjects did, regardless of age. Both recent and remote uses of tamoxifen were associated with an increased likelihood of diabetes.
  
  
  CONCLUSIONS
  The results of this population-based cohort study suggested that tamoxifen use in breast cancer patients might increase subsequent diabetes risk. The underlying mechanism remains unclear and further larger studies are mandatory to validate our findings.
authors.affiliation: Department of Radiation Oncology, Zuoying Branch of Kaohsiung Armed Forces General Hospital, Kaohsiung, Taiwan.
authors.forename: L-M
authors.initials: LM
authors.lastname: Sun
authors.affiliation: Management Office for Health Data, China Medical University Hospital, Taichung, Taiwan.
authors.forename: H-J
authors.initials: HJ
authors.lastname: Chen
authors.affiliation: 1] Department of Radiation Oncology, China Medical University Hospital, Taichung, Taiwan [2] Graduate Institute of Clinical Medical Science and School of Medicine, College of Medicine, China Medical University, Taichung, Taiwan.
authors.forename: J-A
authors.initials: JA
authors.lastname: Liang
authors.affiliation: 1] Graduate Institute of Biostatistics, College of Management, China Medical University, Taichung, Taiwan [2] Department of Healthcare Administration, College of Health Science, Asia University, Taichung, Taiwan.
authors.forename: T-C
authors.initials: TC
authors.lastname: Li
authors.affiliation: 1] Graduate Institute of Clinical Medical Science and School of Medicine, College of Medicine, China Medical University, Taichung, Taiwan [2] Department of Nuclear Medicine and PET Center, China Medical University Hospital, Taichung, Taiwan.
authors.forename: C-H
authors.initials: CH
authors.lastname: Kao
mesh_terms: D000328:Adult; D001943:Breast Neoplasms / Q000188:drug therapy*; D015331:Cohort Studies; D003920:Diabetes Mellitus / Q000139:chemically induced* / Q000453:epidemiology*; D004965:Estrogen Antagonists / Q000009:adverse effects*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D008875:Middle Aged; D009313:National Health Programs; D009367:Neoplasm Staging; D011379:Prognosis; D012307:Risk Factors; D013624:Taiwan / Q000453:epidemiology; D013629:Tamoxifen / Q000009:adverse effects*; D055815:Young Adult
chemical_list: D004965:Estrogen Antagonists; D013629:Tamoxifen