Smoking and risk of sleep-related issues: a systematic review and meta-analysis of prospective studies

Objectives Smoking has many deleterious consequences on health, one of which can be sleep-related issues. Therefore, a meta-analysis was performed with the aim of pooling results from studies on the relationship between smoking and sleep-related issues. Methods The present study follows PRISMA guidelines. Databases were searched by both researchers to find the articles. The review was done up to December 2018. In order to analyze the results of the screened articles, statistical indexes were converted to logarithms and the studies were combined with each other. Finally, several analyses were conducted with respect to various subgroups. In the subgroup analysis, the pool index of the studies was determined and the degree of heterogeneity in each subgroup was presented. Meta-regression was also used. Results Smoking is associated with a risk of developing sleep-related issues. Risk ratio (1.47; 1.20-1.79) for smokers was higher than for non-smokers. Egger's test and Begg's test indicated publication bias. Conclusions Smoking is associated with sleep-related issues. Informing smokers about the effects of smoking on sleep issues can be effective in reducing and preventing its consequences.