title: Parental celiac disease and risk of asthma in offspring: a Danish nationwide cohort study.
abstract: OBJECTIVE
  The incidences of celiac disease (CD) and asthma are increasing and the two conditions are associated in individuals. Risk of asthma may be passed on to the next generation through shared risk factors. We examined whether parental CD is associated with risk of asthma in offspring.
  
  
  METHODS
  We conducted a population-based Danish nationwide cohort study, using medical databases, covering the period 1 January 1979 to 31 December 2009. For each child with a parental history of CD, we randomly sampled 100 children without this history from the children born in the same calendar year. We used Cox proportional-hazards regression to estimate incidence rate ratios for asthma, adjusting for measured covariates.
  
  
  RESULTS
  We identified 1,107 children with a parental history of CD and 110,700 children without this parental history. During up to 32 years of follow-up, 6,125 children received a hospital diagnosis of asthma. The adjusted incidence rate ratio for asthma associated with a parental history of CD was 1.09 (95% confidence interval: 0.86-1.39) and was similar for maternal and paternal CD. Inclusion of asthma-medication in the definition of asthma did not substantially change the results.
  
  
  CONCLUSIONS
  There was no convincing evidence of an increased risk of asthma among offspring of parents with CD.
authors.affiliation: Department of Clinical Epidemiology, Aarhus University Hospital, Aarhus, Denmark.
authors.forename: Ane Birgitte Telén
authors.initials: AB
authors.lastname: Andersen
authors.affiliation: Department of Clinical Epidemiology, Aarhus University Hospital, Aarhus, Denmark.
authors.forename: Rune
authors.initials: R
authors.lastname: Erichsen
authors.affiliation: Department of Pediatrics, Division of Pediatric Gastroenterology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
authors.forename: Michael David
authors.initials: MD
authors.lastname: Kappelman
authors.affiliation: Department of Clinical Epidemiology, Aarhus University Hospital, Aarhus, Denmark.
authors.forename: Trine
authors.initials: T
authors.lastname: Frøslev
authors.affiliation: Department of Clinical Epidemiology, Aarhus University Hospital, Aarhus, Denmark.
authors.forename: Vera
authors.initials: V
authors.lastname: Ehrenstein
keywords: asthma; celiac disease; children; cohort study; parents