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

Aims: To examine whether English legislation to make virtually all indoor public places and workplaces smoke free on 1st 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 4-15 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 >1.7ng/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 threshold the odds of having cotinine > 1.7ng/ml did not change after adjustment for the pre-legislative trend and confounders (OR: 1.0, 95% CI: 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 workplaces 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 amongst these children.