title: Asthma and Risk of Appendicitis in Children: A Population-Based Case-Control Study.
abstract: To assess whether asthma is associated with risk of appendicitis in children.
  
  
  
  We used a population-based case-control study design using a comprehensive medical record review and predetermined criteria for appendicitis and asthma. All children (age younger than 18 years of age) who resided in Olmsted County, Minnesota, and developed appendicitis between 2006 and 2012 were matched to controls (1:1) with regard to birthday, gender, registration date, and index date. Asthma status was ascertained using predetermined criteria. Active (current) asthma was defined as the presence of asthma symptoms or asthma-related events (eg, medication use, clinic visits, emergency department, or hospitalization) within 1 year before the index date. Inactive asthma was defined as subjects without these events. A conditional logistic regression model was used.
  
  
  
  Among the 309 appendicitis cases identified, when stratified according to asthma status, active asthma was associated with significantly increased risk of appendicitis compared with inactive asthma (odds ratio [OR] = 2.48; 95% confidence interval [CI], 1.22-5.03) and to no asthma (OR = 1.88; 95% CI, 1.07-3.27; overall P = .035). When controlling for potential confounders such as gender, age, and smoking status, active asthma was associated with a higher odds of developing appendicitis compared with nonasthmatic patients (adjusted OR = 1.75; 95% CI, 0.99-3.11) whereas inactive asthma was not (overall P = .049). Tobacco smoke exposure within 3 months was associated with an increased risk of appendicitis (adjusted OR = 1.66; 95% CI, 1.02-2.69). Among asthma medications, leukotriene receptor antagonists reduced the risk of appendicitis (OR = 0.18; 95% CI, 0.04-0.74).
  
  
  
  Active asthma might be an unrecognized risk factor for appendicitis in children whereas a history of inactive asthma does not pose such risk. Further investigation exploring the underlying mechanisms is warranted.
authors.affiliation: Mayo Medical School, Mayo Clinic, Rochester, Minn.
authors.forename: M Earth
authors.initials: ME
authors.lastname: Hasassri
authors.affiliation: Mayo Medical School, Mayo Clinic, Rochester, Minn.
authors.forename: Eric R
authors.initials: ER
authors.lastname: Jackson
authors.affiliation: Department of Pediatric and Adolescent Medicine, Mayo Clinic, Rochester, Minn.
authors.forename: Husam
authors.initials: H
authors.lastname: Ghawi
authors.affiliation: Department of Pediatrics, Gil Hospital, Gachon University School of Medicine, Inchon, South Korea.
authors.forename: Eell
authors.initials: E
authors.lastname: Ryoo
authors.affiliation: Department of Pediatric and Adolescent Medicine, Mayo Clinic, Rochester, Minn; Pediatric Asthma Epidemiology Research Unit, Mayo Clinic, Rochester, Minn.
authors.forename: Chung-Il
authors.initials: CI
authors.lastname: Wi
authors.affiliation: Department of Internal Medicine, Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, Minn.
authors.forename: Mark G
authors.initials: MG
authors.lastname: Bartlett
authors.affiliation: Department of Pediatrics, Division of Allergic Diseases, Mayo Clinic, Rochester, Minn.
authors.forename: Gerald W
authors.initials: GW
authors.lastname: Volcheck
authors.affiliation: Department of Pediatric Surgery, Mayo Clinic, Rochester, Minn.
authors.forename: Christopher R
authors.initials: CR
authors.lastname: Moir
authors.affiliation: Department of Health Sciences Research, Mayo Clinic, Rochester, Minn.
authors.forename: Euijung
authors.initials: E
authors.lastname: Ryu
authors.affiliation: Department of Pediatric and Adolescent Medicine/Internal Medicine, Mayo Clinic, Rochester, Minn; Pediatric Asthma Epidemiology Research Unit, Mayo Clinic, Rochester, Minn. Electronic address: juhn.young@mayo.edu.
authors.forename: Young J
authors.initials: YJ
authors.lastname: Juhn
mesh_terms: D000293:Adolescent; D018927:Anti-Asthmatic Agents / Q000627:therapeutic use; D001064:Appendicitis / Q000453:epidemiology*; D001249:Asthma / Q000188:drug therapy / Q000453:epidemiology*; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D004781:Environmental Exposure / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D020024:Leukotriene Antagonists / Q000627:therapeutic use; D016015:Logistic Models; D008297:Male; D008910:Minnesota / Q000453:epidemiology; D015999:Multivariate Analysis; D016017:Odds Ratio; D065840:Protective Factors; D012189:Retrospective Studies; D012307:Risk Factors; D014028:Tobacco Smoke Pollution / Q000706:statistics & numerical data*
chemical_list: D018927:Anti-Asthmatic Agents; D020024:Leukotriene Antagonists; D014028:Tobacco Smoke Pollution
keywords: appendicitis; asthma; atopy; control; epidemiology; gastrointestinal inflammation; risk