Children's exposure to second-hand smoke before and after the smoking ban in Bavaria-a multiple cross-sectional study

The federal state of Bavaria, Germany enforced a comprehensive smoking ban across all enclosed public areas in 2008 to protect non-smokers from second-hand smoke (SHS). Evidence against displacement of smoking to homes is abundant, however long-term assessments are few. We aim to report prevalence of children's SHS exposure before and after the ban, parental smoking behaviour and exposure risk factors. Cross-sectional data of children aged 5-6 years old in Bavaria (n = 22 944) were collected in 2004/5 and 2005/6 (S1 and S2) before the ban and after in 2008/9 and 2012/13 (S4 and S6). Parents reported their child's home SHS exposure, in enclosed public areas and private cars. Adjusted multivariable logistic regression assessed changes across time and predicted risk factors. Children's home SHS exposure before the ban was 14.3% (S1), 14.1% (S2) and 12.8% (S4) directly after the ban to 7.2% (S6) (P