title: Roads, railways, and childhood cancers.
abstract: OBJECTIVE
  To locate geographical sources of engine exhaust emissions in Great Britain and to link them with the birth addresses of children dying from cancer. To estimate the cancer initiating roles of nearby roads and railways and to measure effective ranges.
  
  
  METHODS
  Birth and death addresses of all children born between 1955 and 1980 in Great Britain, and dying from leukaemia or other cancer during those years, were linked to locations of railway stations, bus stations, ferry terminals, railways, roads, canals, and rivers. Nearest distances to births and deaths were measured, and migration data relating to children who had moved house were analysed. Excesses of close to hazard birth addresses, compared with close to hazard death addresses, indicate a high prenatal or early postnatal risk of cancer initiation.
  
  
  METHODS
  Child cancer birth and death addresses and their map references were extracted from an earlier inquiry. Map references of putative hazards were downloaded from the Ordnance Survey national digital map of Great Britain. These data are recorded to a precision of one metre and have ground accuracies around 20 metres.
  
  
  RESULTS
  Significant birth excesses were found within short distances of bus stations, railway stations, ferries, railways, and A,B class roads, with a relative risk of 2.1 within 100 m, tapering to neutral after 3.0 km. About 24% of child cancers were attributable to these joint birth proximities. Roads exerted the major effect.
  
  
  CONCLUSIONS
  Child cancer initiations are strongly determined by prenatal or early postnatal exposures to engine exhaust gases, probably through maternal inhalation and accumulation of carcinogens over many months. The main active substance is probably 1,3-butadiene.
authors.affiliation: Mill Cottage, Front Street, Great Comberton, Pershore, Worcestershire WR10 3DU, UK. E.G.Knox@btinternet.com
authors.forename: E G
authors.initials: EG
authors.lastname: Knox
mesh_terms: D000393:Air Pollutants / Q000633:toxicity*; D001336:Automobiles; D002070:Butadienes / Q000633:toxicity; D002248:Carbon Monoxide / Q000633:toxicity; D002648:Child; D002675:Child, Preschool; D004781:Environmental Exposure / Q000009:adverse effects*; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D009369:Neoplasms / Q000139:chemically induced / Q000453:epidemiology*; D011890:Railroads; D006113:United Kingdom / Q000453:epidemiology
chemical_list: D000393:Air Pollutants; D002070:Butadienes; D002248:Carbon Monoxide; C031763:1,3-butadiene