Smoking restrictions in the home and secondhand smoke exposure among primary schoolchildren before and after introduction of the Scottish smoke-free legislation

Objective: To examine change in home smoking restrictions one year after introduction of Scottish smoke-free legislation, and whether type of restriction impacts upon secondhand smoke (SHS) exposure among children. Design: Comparison of nationally representative, cross-sectional, class-based surveys carried out in the same schools before and after legislation. Participants: 2527 primary schoolchildren (aged around 11 years) surveyed in January 2006 and 2379 in January 2007. Outcome measures: Self-reported home smoking restrictions, salivary cotinine concentrations. Results: Children surveyed after implementation of legislation were more likely than those surveyed before its introduction to report complete home smoking restrictions as opposed to partial (relative risk ratio (partial vs complete) 0.75 (95% CI 0.63 to 0.89) or no restrictions (RR (no restrictions vs complete) 0.50 (0.40 to 0.63). Children living with smokers were less likely to have stringent restrictions in place compared with children living with non-smokers (for both vs neither parents smoke: RR (partial vs complete) 18.29 (13.26 to 25.22) and RR (no restrictions vs complete) 104.73 (70.61 to 155.33). Among smoking households, restriction type varied according to the number and gender of parents who smoke. In both smoking and non-smoking households, children's SHS exposure was directly related to type of home smoking restriction, with lowest exposures among those reporting complete restrictions. Conclusion: This study has shown an increase in the proportion of children reporting a complete ban on smoking in their household after the introduction of smoke-free legislation and supports growing evidence of the wider impact smoke-free legislation can have on smoker behaviour. However, quitting smoking combined with complete home smoking bans will still afford children the best protection from SHS exposure.