title: Exposure to Beta-(1,3)-D-glucan in house dust at age 7-10 is associated with airway hyperresponsiveness and atopic asthma by age 11-14.
abstract: BACKGROUND
  Mould exposure has been linked to childhood asthma and bronchial hyper-responsiveness. Few studies have assessed beta-(1,3)-d-glucan (beta-glucan), a significant fungal cell wall constituent, in relation to asthma in adolescence.
  
  
  OBJECTIVE
  To determine whether house dust-derived beta-glucan exposure at age 7-10 is associated with the development and persistence of atopic and non-atopic asthma, and bronchial hyper-responsiveness (BHR) by age 11-14.
  
  
  METHODS
  Dust samples were collected from the 1995 Study of Asthma, Genes, and Environment (SAGE) birth cohort. This cohort was derived from Manitoba provincial healthcare administrative records of children high and low risk for asthma. Samples were collected from the homes of 422 children at age 7-10 and analyzed using beta-glucan and endotoxin-specific Limulus Amoebocyte Lysate assays. Asthma, atopy, and BHR status of each child were also assessed at ages 7-10 and 11-14.
  
  
  RESULTS
  At age 7-10, beta-glucan dust levels in the home were associated with persistent atopic asthma at age 11-14 (OR 1.79 for each unit increase in levels, 95% CI 1.14-2.81), independent of endotoxin exposure, and Alternaria or Cladosporium sensitization. The likelihood of BHR almost doubled with unit increases in dust beta-glucan in asthmatic children. In children without asthma, exposure to high beta-glucan levels at age 7-10 also elevated risk for BHR in adolescence (OR 1.74, 95% CI 1.05-2.89). New-onset atopic asthma was twice more likely following high beta-glucan exposure in children without asthma but the association did not reach statistical significance. No associations were evident with concurrent asthma phenotype at age 7-10 or non-atopic asthma at age 11-14.
  
  
  CONCLUSIONS
  These findings implicate home beta-glucan exposure at school-age as a risk factor for persistent atopic asthma and new-onset BHR. The higher prevalence of BHR in urban adolescents may be propagated by this home exposure.
authors.affiliation: Faculty of Medicine, Nursing, and Health Sciences, Monash University, Melbourne, Victoria, Australia.
authors.forename: Dharini
authors.initials: D
authors.lastname: Maheswaran
authors.affiliation: Department of Pediatrics, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada.
authors.forename: Yiye
authors.initials: Y
authors.lastname: Zeng
authors.affiliation: Department of Medicine, University of British Columbia, Vancouver, British Columbia, Canada.
authors.forename: Moira
authors.initials: M
authors.lastname: Chan-Yeung
authors.affiliation: Dalla Lana School of Public Health, University of Toronto, Toronto, Ontario, Canada.
authors.forename: James
authors.initials: J
authors.lastname: Scott
authors.affiliation: Department of Pediatrics, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada.
authors.forename: Alvaro
authors.initials: A
authors.lastname: Osornio-Vargas
authors.affiliation: Department of Pediatrics and Child Health, Faculty of Medicine, University of Manitoba, Winnipeg, Manitoba, Canada.
authors.forename: Allan B
authors.initials: AB
authors.lastname: Becker
authors.affiliation: Department of Pediatrics, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada; School of Public Health, University of Alberta, Edmonton, Alberta, Canada.
authors.forename: Anita L
authors.initials: AL
authors.lastname: Kozyrskyj
mesh_terms: D000293:Adolescent; D000367:Age Factors; D001249:Asthma / Q000139:chemically induced* / Q000453:epidemiology; D016535:Bronchial Hyperreactivity / Q000139:chemically induced* / Q000453:epidemiology; D002648:Child; D004391:Dust / Q000032:analysis*; D004731:Endotoxins / Q000633:toxicity; D004781:Environmental Exposure / Q000009:adverse effects*; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D010641:Phenotype; D015995:Prevalence; D011509:Proteoglycans; D047071:beta-Glucans / Q000009:adverse effects*
chemical_list: D004391:Dust; D004731:Endotoxins; D011509:Proteoglycans; D047071:beta-Glucans; C010770:polysaccharide-K