title: Increased risk of fracture in patients with bipolar disorder: a nationwide cohort study.
abstract: Bipolar disorder (BD) is a systemic inflammatory disease, and disrupted bone metabolism due to the inflammatory process can cause fracture. Despite evidence of an association between lower bone mineral density and an increased risk of fracture among patients with depression, schizophrenia, and anorexia nervosa, whether BD is a risk factor for subsequent fracture is unknown. To determine the association between BD and fracture and to examine the risk factors for fracture among patients with BD.
  
  
  
  In this study, we enrolled patients diagnosed with BD from the Taiwan National Health Insurance Research Database. Patients newly diagnosed with BD (ICD-9-CM 296) from 2001 to 2008 were included in the BD cohort, and the date of the initial diagnosis of BD was used as the index date. The comparison cohort, comprising participants without BD, was frequency matched to the BD cohort by age, sex, and index year, and the occurrence of fracture was evaluated in both cohorts.
  
  
  
  The BD and comparison cohorts were comprised of 47,271 patients with BD and 1,89,084 frequency-matched participants without BD, respectively. The incidence of fracture was higher among patients with BD than among the controls. Cox models showed that BD was an independent risk factor for fracture irrespective of comorbidities [hazard ratio (HR) = 1.79, 95 % confidence interval (CI) = 1.73-1.84, p < .001].
  
  
  
  Our study showed that patients with BD have a higher risk of subsequent fracture. Additional prospective clinical studies investigating the relationship between BD and fracture are warranted.
authors.affiliation: Department of Psychiatry, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan.
authors.forename: Chih-Chao
authors.initials: CC
authors.lastname: Hsu
authors.affiliation: Institute of Biomedical Sciences, Mackay Medical College, New Taipei, Taiwan.
authors.forename: Yi-Chao
authors.initials: YC
authors.lastname: Hsu
authors.affiliation: Department of Public Health, China Medical University, Taichung, Taiwan.
authors.forename: Kuang-Hsi
authors.initials: KH
authors.lastname: Chang
authors.affiliation: College of Medicine, The School of Chinese Medicine for Post Baccalaureate, I-Shou University (Yancho Campus), Kaohsiung, Taiwan.|Department of Chinese Medicine, E-DA Hospital, Kaohsiung, Taiwan.
authors.forename: Chang-Yin
authors.initials: CY
authors.lastname: Lee
authors.affiliation: Division of Hepatology and Gastroenterology, Department of Internal Medicine, Shin Kong Wu Ho-Su Memorial Hospital, Taipei, Taiwan.
authors.forename: Lee-Won
authors.initials: LW
authors.lastname: Chong
authors.affiliation: Management Office for Health Data, China Medical University Hospital, Taichung, Taiwan.
authors.forename: Yu-Chiao
authors.initials: YC
authors.lastname: Wang
authors.affiliation: Graduate Institute of Clinical Medical Science and School of Medicine, College of Medicine, China Medical University, No. 2, Yuh-Der Road, Taichung, 40447, Taiwan.
authors.forename: Chung-Y
authors.initials: CY
authors.lastname: Hsu
authors.affiliation: Graduate Institute of Clinical Medical Science and School of Medicine, College of Medicine, China Medical University, No. 2, Yuh-Der Road, Taichung, 40447, Taiwan. d10040@mail.cmuh.org.tw.|Department of Nuclear Medicine and PET Center, China Medical University Hospital, Taichung, Taiwan. d10040@mail.cmuh.org.tw.
authors.forename: Chia-Hung
authors.initials: CH
authors.lastname: Kao
mesh_terms: D000328:Adult; D000368:Aged; D001714:Bipolar Disorder / Q000453:epidemiology*; D015331:Cohort Studies; D015897:Comorbidity; D016208:Databases, Factual; D005260:Female; D050723:Fractures, Bone / Q000453:epidemiology*; D006801:Humans; D015994:Incidence; D038801:International Classification of Diseases; D008297:Male; D008875:Middle Aged; D009313:National Health Programs; D016016:Proportional Hazards Models; D011446:Prospective Studies; D012307:Risk Factors; D013624:Taiwan / Q000453:epidemiology
keywords: Bipolar disorder; Fracture; Taiwan National Health Insurance Research Database