title: Weighted road density and allergic disease in children at high risk of developing asthma.
abstract: BACKGROUND
  Evidence for an association between traffic-related air pollution and allergic disease is inconsistent, possibly because the adverse effects may be limited to susceptible subgroups and these have not been identified. This study examined children in the Childhood Asthma Prevention Study (CAPS), potentially susceptible to air pollution effects because of a family history of asthma.
  
  
  METHODS
  We examined cross-sectional associations at age eight years between road density within 75 m and 50 m of home address weighted by road type (traffic density), as a proxy for traffic-related air pollution, on the following allergic and respiratory outcomes: skin prick tests (SPTs), total and specific serum IgE, pre- and post-bronchodilator lung function, airway hyperresponsiveness, exhaled NO, and reported asthma and rhinitis.
  
  
  RESULTS
  Weighted road density was positively associated with allergic sensitisation and allergic rhinitis. Adjusted relative risk (RR) for house dust mite (HDM) positive SPT was 1.25 (95% CI: 1.06-1.48), for detectable house dust mite-specific IgE was 1.19 (95% CI: 1.01-1.41) and for allergic rhinitis was 1.30 (95% CI: 1.03-1.63) per 100 m local road or 33.3 m motorway within 50 m of home. Associations were also seen with small decrements of peak and mid-expiratory flows and increased risk of asthma, current wheeze and rhinitis in atopic children.
  
  
  CONCLUSIONS
  Associations between road density and allergic disease were found in a potentially susceptible subgroup of children at high risk of developing atopy and asthma.
authors.affiliation: MRC-PHE Centre for Environment and Health, Imperial College London, London, United Kingdom; Public Health and Primary Care Directorate, Imperial College Healthcare NHS Trust, London, United Kingdom.
authors.forename: Anna L
authors.initials: AL
authors.lastname: Hansell
authors.affiliation: Woolcock Institute of Medical Research, University of Sydney, Sydney, New South Wales, Australia; New South Wales Health Ministry, Sydney, New South Wales, Australia.
authors.forename: Nectarios
authors.initials: N
authors.lastname: Rose
authors.affiliation: Woolcock Institute of Medical Research, University of Sydney, Sydney, New South Wales, Australia; South West Sydney Clinical School, University of New South Wales, Liverpool, New South Wales, Australia.
authors.forename: Christine T
authors.initials: CT
authors.lastname: Cowie
authors.affiliation: Woolcock Institute of Medical Research, University of Sydney, Sydney, New South Wales, Australia.
authors.forename: Elena G
authors.initials: EG
authors.lastname: Belousova
authors.affiliation: MRC-PHE Centre for Environment and Health, Imperial College London, London, United Kingdom.
authors.forename: Ioannis
authors.initials: I
authors.lastname: Bakolis
authors.affiliation: Woolcock Institute of Medical Research, University of Sydney, Sydney, New South Wales, Australia.
authors.forename: Kitty
authors.initials: K
authors.lastname: Ng
authors.affiliation: Woolcock Institute of Medical Research, University of Sydney, Sydney, New South Wales, Australia; Sydney Local Health District, Sydney, New South Wales, Australia.
authors.forename: Brett G
authors.initials: BG
authors.lastname: Toelle
authors.affiliation: Woolcock Institute of Medical Research, University of Sydney, Sydney, New South Wales, Australia; South West Sydney Clinical School, University of New South Wales, Liverpool, New South Wales, Australia; Department of Respiratory Medicine, Liverpool Hospital, Liverpool, New South Wales, Australia.
authors.forename: Guy B
authors.initials: GB
authors.lastname: Marks
mesh_terms: D000397:Air Pollution; D000485:Allergens / Q000145:classification / Q000633:toxicity*; D000818:Animals; D001249:Asthma / Q000097:blood / Q000139:chemically induced / Q000503:physiopathology*; D002648:Child; D004781:Environmental Exposure; D005260:Female; D006801:Humans; D007073:Immunoglobulin E / Q000097:blood; D008297:Male; D012221:Rhinitis, Allergic, Perennial / Q000097:blood / Q000139:chemically induced / Q000503:physiopathology*; D001335:Vehicle Emissions / Q000633:toxicity*
chemical_list: D000485:Allergens; D001335:Vehicle Emissions; D007073:Immunoglobulin E