Association between obstructive sleep apnea and alcohol, caffeine and tobacco: A meta-analysis

The aim of this systematic review was to answer the focused question, "Is there an association between obstructive sleep apnea (OSA) and alcohol, caffeine or tobacco use?" Five electronic databases (Cinahl, Literatura Latth American and Caribbean, PubMed, Scopus, Web of Science) and 3 grey literature (Google Acadêmico, ProQuest, OpenGrey) were searched, as well as search on reference list of included papers and contacts with study authors. Observational studies were included. The Meta-Analysis of Statistics Assessment and Review Instrument (MAStARI) tool assessed the potential risk of bias (RoB) among the studies, while the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach determined the level of evidence. Meta-Analysis was performed with RevMan 5.3 software. Among 3,442 identified studies, 14 were included. Eleven studies were classified as moderate RoB and 3 as high RoB. Meta-analysis showed OSA has no association with tobacco and presented a positive association with alcohol. The odds ratio for OSA increased almost 1.33 times (95% confidence interval [CI]; 1.10-1.62) for alcohol users. There was insufficient published data to evaluate whether OSA is associated with caffeine. The overall quality of evidence ranged from low to very low. OSA was associated with the use of alcohol, however there is not enough evidence to confirm the association with tobacco or caffeine. Due to the very low GRADE level of evidence, caution should be applied when considering these findings.