title: The use of synthetic bedding in children. Do strategies of change influence associations with asthma?
abstract: BACKGROUND
  Epidemiological data suggest in contrast to clinical recommendations a negative effect of synthetic bedding on asthma and respiratory symptoms.
  
  
  OBJECTIVE
  To assess the effects of bedding filled with synthetic material on the risk of asthma and respiratory symptoms in 6- to 7-year-old children, taking into account allergy-related change of bedding material.
  
  
  METHODS
  We analyzed data from the ISAAC Phase III cross-sectional survey (1999/2000) in Münster, Germany. Data were collected by parental report from representative school-based samples of 6- to 7-year old children (n = 3,529). We calculated prevalence ratios with 95% confidence intervals for the association between respiratory symptoms suggestive of asthma and synthetic pillows and blankets and adjusting for potential confounders.
  
  
  RESULTS
  In the preliminary analyses, synthetic pillows and synthetic blankets were positively associated with the studied respiratory outcomes. For example, a high number of wheezing attacks was positively associated with synthetic pillows (PR = 4.44; 95% CI 2.84-6.94) and synthetic blankets (PR = 3.80; 95% CI 2.48-5.82). However, in the restricted analysis, excluding participants reporting allergy-related change of bedding (pillows n = 440; blankets n = 437), the positive associations disappeared for all studied outcomes.
  
  
  CONCLUSIONS
  Our findings suggest that allergy-related choice of bedding is an important factor in the assessment of the relation between synthetic bedding and asthma symptoms. Ignoring those changes can lead to false-positive risk estimates. Prospective studies that allow to disentangle the temporal sequence of disease, exposure, and change of bedding should help to further clarify this issue.
authors.affiliation: Institute of Epidemiology and Social Medicine, University of Münster, Münster, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Behrens
authors.forename: Wasim
authors.initials: W
authors.lastname: Maziak
authors.forename: Stephan K
authors.initials: SK
authors.lastname: Weiland
authors.forename: Edith
authors.initials: E
authors.lastname: Siebert
authors.forename: Peter
authors.initials: P
authors.lastname: Rzehak
authors.forename: Ulrich
authors.initials: U
authors.lastname: Keil
mesh_terms: D000485:Allergens / Q000276:immunology*; D001249:Asthma / Q000276:immunology*; D001512:Bedding and Linens / Q000009:adverse effects*; D002648:Child; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D011795:Surveys and Questionnaires
chemical_list: D000485:Allergens