What does existing English literature say about the association between secondhand smoke (SHS) and sleep-disordered breathing (SDB) in children?
Background: The U.S. Surgeon General’s report on involuntary smoke exposure in 2006 concluded that approximately 60% of U.S. children aged 3 to 11 are exposed to SHS. A limited number of previous studies have shown that SDB is more common in patients exposed to SHS than in the general population, and SHS has been identified as an SDB risk factor. Reducing SHS exposure may lead to SDB improvement in affected children, but the relationship must be better understood.
Explore this issue:January 2015
Study design: Literature review of 18 articles with a total study population of 47,462 patients from inception date through February 2013.
Setting: PubMed, Embase, Cochrane CENTRAL, Web of Science, and Scopus.
Synopsis: Fifteen articles showed a statistically significant association between SHS and SDB, while three found no significant relationship. All included articles were case control studies (level 3b evidence); there were no randomized controlled trials (level 1 evidence). The Newcastle-Ottawa Scale was used to assess study quality; each study was assigned up to nine total stars based on three categories: selection of cases and controls, comparability of controls on basis of design/analysis, and methods of ascertaining exposure. The mean number of stars for included studies was 5.8/9. Five studies were categorized as high quality (7/9). The most commonly studied SDB was habitual snoring.
Several studies have also identified a more significant association between SDB and maternal smoking that is greater than that found with paternal smoking. No studies reported on SDB reversibility with decreased SHS exposure or demonstrated a causal relationship, but several reported a dose-response relationship. The primary limitations were lack of prospective, high-level studies, the inherent bias risk of case-control studies, inclusion of only English language studies, and SHS and SDB measurement method variations.
Bottom line: Although the majority of studies found a significant association between secondhand smoke and sleep-disordered breathing, a higher level of evidence quality is needed for more definitive results.
Reviewed by Amy E. Hamaker