title: Association of primary immune thrombocytopenia and common allergic diseases among children.
abstract: BACKGROUND
  Growing evidence has revealed a link between autoimmune and allergic diseases. However, few studies have assessed the relationship between allergic diseases and primary immune thrombocytopenia (ITP), an autoimmune disease frequently occurring in children. This population-based case-control study investigated the association between common allergic diseases and the subsequent risk of developing ITP during childhood.
  
  
  METHODS
  This study investigated 1,203 children younger than 18 y of age who were diagnosed with ITP between 1998 and 2008, as well as 4,812 frequency-matched controls. The odds ratios of the association between ITP and preexisting allergic diseases were calculated.
  
  
  RESULTS
  Children with every type of allergic disease examined in this study (except asthma) exhibited an increased risk of developing ITP; the lowest adjusted odds ratio (aOR) was 1.39 for allergic conjunctivitis (95% confidence interval (CI) = 1.09-1.79), whereas the greatest aOR was 1.84 for allergic rhinitis (95% CI = 1.49-2.27). The aORs increased with the number of concurrent allergic diseases to 2.89 (95% CI = 1.98-4.22) for children with at least three allergic diseases.
  
  
  CONCLUSIONS
  Children with atopic diathesis have a greater risk of subsequently developing ITP. The fundamental determinants of this relationship warrant further study.
authors.affiliation: Department of Pediatrics, Taichung Veterans General Hospital, Taichung, Taiwan.
authors.forename: Ming-Ru
authors.initials: MR
authors.lastname: Chiang
authors.affiliation: 1] Department of Nephrology, Children's Hospital, China Medical University Hospital, Taichung, Taiwan [2] College of Medicine, China Medical University, Taichung, Taiwan.
authors.forename: Chang-Ching
authors.initials: CC
authors.lastname: Wei
authors.affiliation: Management Office for Health Data, China Medical University Hospital, Taichung, Taiwan.
authors.forename: Chin-Shin
authors.initials: CS
authors.lastname: Muo
authors.affiliation: Department of Pediatrics, Taichung Veterans General Hospital, Taichung, Taiwan.
authors.forename: Lin-Shien
authors.initials: LS
authors.lastname: Fu
authors.affiliation: Department of Public Health, China Medical University, Taichung, Taiwan.
authors.forename: Tsai-Chung
authors.initials: TC
authors.lastname: Li
authors.affiliation: 1] Department of Nuclear Medicine and PET Center, 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: Chia-Hung
authors.initials: CH
authors.lastname: Kao
mesh_terms: D000293:Adolescent; D001249:Asthma / Q000150:complications / Q000453:epidemiology; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D006967:Hypersensitivity / Q000150:complications* / Q000453:epidemiology; D015994:Incidence; D007223:Infant; D008297:Male; D016017:Odds Ratio; D016016:Proportional Hazards Models; D016553:Purpura, Thrombocytopenic, Idiopathic / Q000150:complications* / Q000453:epidemiology; D065631:Rhinitis, Allergic / Q000150:complications / Q000453:epidemiology; D012307:Risk Factors