title: Association between allergic diseases and risks of HSP and HSP nephritis: a population-based study.
abstract: BACKGROUND
  Some allergic inflammation-associated mediators have been reported in acute stage of Henoch-Schönlein purpura (HSP). However, the association of children with allergic diseases and their subsequent risks of HSP and HSP nephritis remain unknown.
  
  
  METHODS
  In this study, we included 2,240 children with HSP diagnosed between 2000 and 2008 as well as 8,960 non-HSP controls matched for age, sex, and level of urbanization. The odds ratios (ORs) of HSP were calculated with respect to associations with pre-existing allergic diseases.
  
  
  RESULTS
  Children with allergic diseases had an increased subsequent risk of HSP; the lowest adjusted OR (aOR) was 1.33 for allergic conjunctivitis (95% confidence interval (CI): 1.17-1.52) and the highest was 1.68 for asthma (95% CI: 1.48-1.91). The aOR increased to 2.03 (95% CI: 1.80-2.31) in children with at least two allergic diseases. Children who visited medical institutes more often per year for associated allergic diseases had an increased risk of HSP. Of the 2,240 children with HSP, 249 (11%) had HSP nephritis and 45.8% of those with nephritis had history of any allergic disease.
  
  
  CONCLUSIONS
  Atopic children had an increased subsequent risk of HSP but not an increased risk of HSP nephritis.
authors.affiliation: Department of Pediatric Medicine, Children's Hospital of China Medical University Hospital, Taichung, Taiwan.|School of Medicine, China Medical University, Taichung, Taiwan.
authors.forename: An-Chyi
authors.initials: AC
authors.lastname: Chen
authors.affiliation: Management Office for Health Data, China Medical University Hospital, Taichung, Taiwan.|Department of Public Health, China Medical University, Taichung, Taiwan.
authors.forename: Cheng-Li
authors.initials: CL
authors.lastname: Lin
authors.affiliation: School of Medicine, China Medical University, Taichung, Taiwan.|Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, China Medical University Hospital, Taichung, Taiwan.
authors.forename: Te-Chun
authors.identifier: http://orcid.org/0000-0002-9427-1068
authors.initials: TC
authors.lastname: Shen
authors.affiliation: Department of Public Health, China Medical University, Taichung, Taiwan.
authors.forename: Tsai-Chung
authors.initials: TC
authors.lastname: Li
authors.affiliation: Department of Public Health, China Medical University, Taichung, Taiwan.
authors.forename: Fung-Chang
authors.initials: FC
authors.lastname: Sung
authors.affiliation: Department of Pediatric Medicine, Children's Hospital of China Medical University Hospital, Taichung, Taiwan.|School of Medicine, China Medical University, Taichung, Taiwan.
authors.forename: Chang-Ching
authors.initials: CC
authors.lastname: Wei
mesh_terms: D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D006967:Hypersensitivity / Q000150:complications*; D011695:IgA Vasculitis / Q000150:complications*; D008297:Male; D009393:Nephritis / Q000150:complications*; D011159:Population Surveillance