Predictors of children's secondhand smoke exposure at home: a systematic review and narrative synthesis of the evidence.
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.


OBJECTIVE
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.


RESULTS
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.


CONCLUSIONS
Multiple factors are associated with child SHS exposure in the home; the best way to reduce child SHS exposure in the home is for smoking parents to quit. If parents are unable or unwilling to stop smoking, they should instigate smoke-free homes. Interventions targeted towards the socially disadvantaged parents aiming to change attitudes to smoking in the presence of children and providing practical support to help parents smoke outside the home may be beneficial.
UK Centre for Tobacco & Alcohol Studies & Division of Primary Care, University of Nottingham, Nottingham, United Kingdom.
Sophie
S
Orton
UK Centre for Tobacco & Alcohol Studies and Unit of Public Health, Epidemiology & Biostatistics, School of Health & Population Sciences, University of Birmingham, Birmingham, United Kingdom.
Laura L
LL
Jones
UK Centre for Tobacco & Alcohol Studies & Division of Primary Care, University of Nottingham, Nottingham, United Kingdom.
Sue
S
Cooper
UK Centre for Tobacco & Alcohol Studies & Division of Epidemiology & Public Health, University of Nottingham, Nottingham, United Kingdom.
Sarah
S
Lewis
UK Centre for Tobacco & Alcohol Studies & Division of Primary Care, University of Nottingham, Nottingham, United Kingdom.
Tim
T
Coleman
D016902:Air Pollution, Indoor / Q000032:analysis*; D002248:Carbon Monoxide / Q000032:analysis; D002648:Child; D003367:Cotinine / Q000032:analysis; D004522:Educational Status; D004781:Environmental Exposure / Q000706:statistics & numerical data*; D006801:Humans; D052638:Particulate Matter / Q000032:analysis; D012959:Socioeconomic Factors; D014028:Tobacco Smoke Pollution / Q000032:analysis*
D052638:Particulate Matter; D014028:Tobacco Smoke Pollution; D002248:Carbon Monoxide; D003367:Cotinine