England's legislation on smoking in indoor public places and work-places: impact on the most exposed children

Aims To examine whether English legislation to make virtually all indoor public places and work-places smoke-free on 1 July 2007 displaced smoking into the home and hence increased the proportion of children exposed to levels of second-hand smoke known to be detrimental to health. Design Repeated cross-sectional study with data from 10 annual surveys undertaken from 1996 to 2008. Setting England. Participants Nationally representative samples of non-smoking children aged 415 years old living in private households. Measurements Salivary cotinine, parental smoking status, whether smoking is allowed within the house, socio-demographic variables. Findings The proportion of children exposed to damaging levels of second-hand smoke (defined as those with cotinine levels >1.7?ng/ml) has fallen over time, from 23.5% in 1996 to 12.6% in 2008. The legislation was not associated with further changes in the proportion of children above this thresholdthe odds of having cotinine >1.7?ng/ml did not change after adjustment for the pre-legislative trend and confounders (odds ratio: 1.0, 95% confidence interval: 0.78, 1.4). Non-significant associations were also found when examining children by parental or household smoking status. Conclusions Legislation to prohibit smoking in indoor public places and work-places does not increase the proportion of children exposed to damaging levels of second-hand smoke. Even in a country with a strong tobacco control climate, a significant proportion of children remain highly exposed to second-hand smoke and future policies need to include interventions to reduce exposure among these children.