title: Risk of cancer in patients with iron deficiency anemia: a nationwide population-based study.
abstract: OBJECTIVE
  This study evaluated the risk of cancer among patients with iron deficiency anemia (IDA) by using a nationwide population-based data set.
  
  
  METHODS
  Patients newly diagnosed with IDA and without antecedent cancer between 2000 and 2010 were recruited from the Taiwan National Health Insurance Research Database. The standardized incidence ratios (SIRs) of cancer types among patients with IDA were calculated.
  
  
  RESULTS
  Patients with IDA exhibited an increased overall cancer risk (SIR: 2.15). Subgroup analysis showed that patients of both sexes and in all age groups had an increased SIR. After we excluded patients diagnosed with cancer within the first and first 5 years of IDA diagnosis, the SIRs remained significantly elevated at 1.43 and 1.30, respectively. In addition, the risks of pancreatic (SIR: 2.31), kidney (SIR: 2.23), liver (SIR: 1.94), and bladder cancers (SIR: 1.74) remained significantly increased after exclusion of patients diagnosed with cancer within 5 years after IDA diagnosis.
  
  
  CONCLUSIONS
  The overall cancer risk was significantly elevated among patients with IDA. After we excluded patients diagnosed with IDA and cancer within 1 and 5 years, the SIRs remained significantly elevated compared with those of the general population. The increased risk of cancer was not confined to gastrointestinal cancer when the SIRs of pancreatic, kidney, liver, and bladder cancers significantly increased after exclusion of patients diagnosed with IDA and cancer within the first 5 years. This finding may be caused by immune activities altered by IDA. Further study is necessary to determine the association between IDA and cancer risk.
authors.affiliation: Department of Psychiatry, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan.
authors.forename: Ning
authors.initials: N
authors.lastname: Hung
authors.affiliation: School of Medicine, National Yang-Ming University, Taipei, Taiwan; Department of Psychiatry, Chiayi Branch, Taichung Veterans General Hospital, Chiayi, Taiwan.
authors.forename: Cheng-Che
authors.initials: CC
authors.lastname: Shen
authors.affiliation: Department of Psychiatry, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan; Department of information magagement, National Chung-Cheng University, Chiayi, Taiwan; Cancer Center, Taipei Veterans General Hospital, Taipei, Taiwan.
authors.forename: Yu-Wen
authors.initials: YW
authors.lastname: Hu
authors.affiliation: Institute of Public Health, National Yang-Ming University, Taipei, Taiwan.
authors.forename: Li-Yu
authors.initials: LY
authors.lastname: Hu
authors.affiliation: Department of Family Medicine, Taipei Veterans General Hospital, Taipei, Taiwan.
authors.forename: Chiu-Mei
authors.initials: CM
authors.lastname: Yeh
authors.affiliation: Department of Psychiatry, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan; Cancer Center, Taipei Veterans General Hospital, Taipei, Taiwan; Division of Oncology and Hematology, Department of Medicine, Far Eastern Memorial Hospital, New Taipei City, Taiwan.
authors.forename: Chung-Jen
authors.initials: CJ
authors.lastname: Teng
authors.affiliation: Department of Psychiatry, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan.
authors.forename: Ai-Seon
authors.initials: AS
authors.lastname: Kuan
authors.affiliation: Division of Hematology and Oncology, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan.
authors.forename: San-Chi
authors.initials: SC
authors.lastname: Chen
authors.affiliation: Cancer Center, Taipei Veterans General Hospital, Taipei, Taiwan; Department of Family Medicine, Taipei Veterans General Hospital, Taipei, Taiwan.
authors.forename: Tzeng-Ji
authors.initials: TJ
authors.lastname: Chen
authors.affiliation: Department of Psychiatry, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan; Cancer Center, Taipei Veterans General Hospital, Taipei, Taiwan; Division of Hematology and Oncology, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan.
authors.forename: Chia-Jen
authors.initials: CJ
authors.lastname: Liu
mesh_terms: D000328:Adult; D000368:Aged; D018798:Anemia, Iron-Deficiency / Q000175:diagnosis / Q000453:epidemiology*; D005500:Follow-Up Studies; D006801:Humans; D008875:Middle Aged; D009369:Neoplasms / Q000175:diagnosis / Q000453:epidemiology*; D012189:Retrospective Studies; D012307:Risk Factors; D013624:Taiwan / Q000453:epidemiology; D013997:Time Factors