Predictors of children’s secondhand smoke exposure at home: a systematic review and narrative synthesis of the evidence. PLoS One 2014; 9: e112690. doi: 10.1371/journal.pone.0112690 PMID: 25397875

Background: Children’s exposure to secondhand smoke (SHS) has been causally linked to a number of childhood morbidities and mortalities. Over 50 % of UK children whose parents are smokers are regularly exposed to SHS at home. No previous review has identified the factors associated with children’s SHS exposure in the home. Aim: To identify by systematic review, the factors which are associated with children’s SHS exposure in the home, determined by parent or child reports and/or biochemically validated measures including cotinine, carbon monoxide or home air particulate matter. Methods: Electronic searches of MEDLINE, EMBASE, PsychINFO, CINAHL and Web of Knowledge to July 2014, and hand searches of reference lists from publications included in the review were conducted. Findings: Forty one studies were included in the review. Parental smoking, low socioeconomic status and being less educated were all frequently and consistently found to be independently associated with children’s SHS exposure in the home. Children whose parents held more negative attitudes towards SHS were less likely to be exposed. Associations were strongest for parental cigarette smoking status; compared to children of non-smokers, those whose mothers or both parents smoked were between two and 13 times more likely to be exposed to SHS. Conclusion: Multiple factors are associated with child SHS exposure in the home; the best way to reduce child SHS exposur