title: Smoke-free homes in England: prevalence, trends and validation by cotinine in children.
abstract: OBJECTIVE
  To examine the prevalence of smoke-free homes in England between 1996 and 2007 and their impact on children's exposure to second-hand smoke via a series of annual cross-sectional surveys: the Health Survey for England. These comprised nationally representative samples of non-smoking children aged 4-15 (n = 13 365) and their parents interviewed in the home. Main outcome measures were cotinine measured in saliva, smoke-free homes defined by "no" response to "Does anyone smoke inside this house/flat on most days?", self-reported smoking status of parents and self-reported and cotinine validated smoking status in children.
  
  
  RESULTS
  The proportion of homes where one parent was a smoker that were smoke free increased from 21% in 1996 to 37% in 2007, and where both parents were smokers from 6% to 21%. The overwhelming majority of homes with non-smoking parents were smoke free (95% in 1996; 99% in 2007). For children with non-smoking parents and living in a smoke-free home the geometric mean cotinine across all years was 0.22 ng/ml. For children with one smoking parent geometric mean cotinine levels were 0.37 ng/ml when the home was smoke free and 1.67 ng/ml when there was smoking in the home; and for those with two smoking parents, 0.71 ng/ml and 2.46 ng/ml. There were strong trends across years for declines in cotinine concentrations in children in smoke-free homes for the children of smokers and non-smokers.
  
  
  CONCLUSIONS
  There has been a marked secular trend towards smoke-free homes, even when parents themselves are smokers. Living in a smoke-free home offers children a considerable, but not complete, degree of protection against exposure to parental smoking.
authors.affiliation: Health Behaviour Research Centre, Department of Epidemiology & Public Health, University College London, London, UK. martin.jarvis@ucl.ac.uk
authors.forename: M J
authors.initials: MJ
authors.lastname: Jarvis
authors.forename: J
authors.initials: J
authors.lastname: Mindell
authors.forename: A
authors.initials: A
authors.lastname: Gilmore
authors.forename: C
authors.initials: C
authors.lastname: Feyerabend
authors.forename: R
authors.initials: R
authors.lastname: West
mesh_terms: D000293:Adolescent; D016902:Air Pollution, Indoor / Q000517:prevention & control* / Q000706:statistics & numerical data; D002648:Child; D002675:Child, Preschool; D003367:Cotinine / Q000032:analysis*; D004739:England / Q000453:epidemiology; D004781:Environmental Exposure / Q000032:analysis / Q000706:statistics & numerical data; D004784:Environmental Monitoring / Q000379:methods; D062665:Epidemiological Monitoring; D005260:Female; D006306:Health Surveys; D006798:Housing / Q000706:statistics & numerical data*; D006801:Humans; D008297:Male; D010290:Parents / Q000523:psychology; D012463:Saliva / Q000737:chemistry; D012907:Smoking / Q000453:epidemiology; D014028:Tobacco Smoke Pollution / Q000517:prevention & control* / Q000706:statistics & numerical data
chemical_list: D014028:Tobacco Smoke Pollution; D003367:Cotinine