title: Risk of type 2 diabetes mellitus in female breast cancer patients treated with morphine: A retrospective population-based time-dependent cohort study.
abstract: OBJECTIVE
  We aimed to examine whether morphine treatment is associated with type 2 diabetes mellitus (T2DM) in female breast cancer patients.
  
  
  METHODS
  We conducted a retrospective cohort analysis of the Longitudinal Health Insurance Database for Catastrophic Illness Patients in Taiwan. A total of 31,112 women with breast cancer without T2DM history during the period 2000-2005 were identified, divided into morphine and non-morphine users (8071 and 23,041 patients, respectively), and the hazard ratios of newly diagnosed T2DM during the period 2005-2010 were calculated. We used a Cox proportional hazard model with time-dependent exposure covariates to estimate the risk of T2DM. The dosage of morphine was counted as defined daily dose and its effect was assessed by multivariable Cox proportional hazard regression controlling age, Charlson comorbidity index, outpatient department visits, antipsychotics, and breast cancer drugs.
  
  
  RESULTS
  Morphine users were 1.24 times more likely to suffer from T2DM than non-morphine users (95% CI=1.04-1.49). Risk increased slightly with the morphine dosage, in patients aged 35-49 years, and with tamoxifen, aromatase inhibitors, and antipsychotics treatment.
  
  
  CONCLUSIONS
  The incidence of T2DM is associated with morphine treatment in female breast cancer patients. A higher risk was observed in patients aged 35-49 years using higher dose of morphine, and may be increased by tamoxifen and aromatase inhibitors.
authors.affiliation: Yang's ENT Clinic, Taichung, Taiwan.
authors.forename: Szu-Pang
authors.initials: SP
authors.lastname: Yang
authors.affiliation: Department of Public Health, China Medical University, Taichung, Taiwan; Management Office for Health Data, China Medical University Hospital, Taichung, Taiwan.
authors.forename: Chih-Hsin
authors.initials: CH
authors.lastname: Muo
authors.affiliation: Department of Internal Medicine, China Medical University Hospital, Taichung, Taiwan; Division of Kidney Disease, College of Medicine, China Medical University, Taichung, Taiwan.
authors.forename: I-Kuan
authors.initials: IK
authors.lastname: Wang
authors.affiliation: Department of Health Promotion and Health Education, National Taiwan Normal University, Taipei, Taiwan.
authors.forename: Yen-Jung
authors.initials: YJ
authors.lastname: Chang
authors.affiliation: Department of Family Medicine, China Medical University Hospital, Taichung, Taiwan; China Medical University, Taichung, Taiwan.
authors.forename: Shih-Wei
authors.initials: SW
authors.lastname: Lai
authors.affiliation: China Medical University, Taichung, Taiwan; Center for Drug Abuse and Addiction, China Medical University Hospital, Taichung, Taiwan. Electronic address: T22529@mail.cmuh.org.tw.
authors.forename: Cynthia Wei-Sheng
authors.initials: CW
authors.lastname: Lee
authors.affiliation: Department of Community Health Sciences, UCLA Fielding School of Public Health, Los Angeles, CA, USA.
authors.forename: Donald E
authors.initials: DE
authors.lastname: Morisky
mesh_terms: D000328:Adult; D000368:Aged; D047072:Aromatase Inhibitors / Q000627:therapeutic use; D001943:Breast Neoplasms / Q000188:drug therapy*; D003924:Diabetes Mellitus, Type 2 / Q000453:epidemiology*; D005260:Female; D006801:Humans; D015994:Incidence; D019290:Megestrol Acetate / Q000627:therapeutic use; D008875:Middle Aged; D009020:Morphine / Q000009:adverse effects* / Q000627:therapeutic use; D016016:Proportional Hazards Models; D012189:Retrospective Studies; D012307:Risk Factors; D013624:Taiwan / Q000453:epidemiology; D013629:Tamoxifen / Q000627:therapeutic use; D055815:Young Adult
chemical_list: D047072:Aromatase Inhibitors; D013629:Tamoxifen; D009020:Morphine; D019290:Megestrol Acetate
keywords: Breast cancer; Cohort analysis; Morphine; Type 2 diabetes mellitus