Background The association between environmental tobacco smoke (ETS) exposure and habitual snoring (HS) risk in children remains controversial. Therefore, a meta-analysis was carried out to evaluate and compare the effect of ETS by different family members and prenatal smoke exposure on the risk of HS in children.

Methods Relevant studies published in English were identified by a search of PubMed, Embase and Web of Science up to December 2017. Random effect model and fixed effect model were used to pool the findings. Restricted cubic splines were used to assess the dose-response relationship.

Results A total of 24 studies with 87 829 participants were included in the present meta-analysis. When comparing ETS exposed with non-ETS exposed, the pooled OR of HS were 1.46 (95% CI, 1.29 to 1.65) for household smoking exposure, 1.45 (95% CI, 1.27 to 1.65) for paternal smoking exposure, 1.87 (95% CI, 1.56 to 2.23) for maternal smoking exposure and 1.95 (95% CI, 1.63 to 2.34) for prenatal tobacco smoke exposure. For dose-response analysis, evidence of a linear association was found between household smoking exposure and HS, and the risk of HS increased by 2.1% (OR=1.02, 95% CI, 1.00 to 1.04, p=0.022) for every 1 cigarette/day increment of smoking by people living with children.

Conclusions This meta-analysis of observational studies indicates that exposure to ETS, in particularly prenatal tobacco smoke exposure and maternal smoking, is associated with an increased risk of HS.