The association between exposure to second-hand smoke and sleep disturbances: A systematic review and meta-analysis

To investigate the association between second-hand smoke (SHS) exposure and sleep disturbances by systematically reviewing the literature base and to quantify this association by conducting a meta-analysis.

We did a systematic search of five databases- PubMed, Embase, CINAHL Plus, Web of Science - Core Collection, and Google Scholar. The primary outcomes were short sleep duration (SSD), poor sleep quality (PSQ), and excessive daytime sleepiness (EDS).

Our systematic search yielded a total of 1623 studies. However, 12 studies qualified for qualitative synthesis and 11 studies (12 surveys) with adequate information were included in the meta-analysis involving 730,808 participants. All the studies were cross-sectional. We found an association between SHS exposure and SSD [pooled OR: 1.20 (95% CI, 1.09-1.33; p = 0.0003; I²= 68%), N = 7]; EDS [pooled OR: 1.07 (95% CI, 1.01-1.13; p = 0.02; I² = 0%), N = 4]; and PSQ [pooled OR: 1.12 (95% CI, 1.01-1.23; p = 0.03; I² = 79%), N = 10]. Subgroup analyses suggest significant association between SHS exposure and PSQ among adolescents. However, no such association was observed among adults. In addition, no significant association was observed between PSQ and SHS exposure when biomarker was used to identify SHS exposure.

This study is the first systematic review and meta-analysis to examine the association between SHS exposure and sleep outcomes. Self-reported exposure to SHS is positively associated with SSD, EDS, and PSQ, although the effects are modest. Further studies with robust methodology to ascertain exposure information are warranted to further elucidate the relationship between SHS exposure and sleep disturbances.