Investigation into the association between obstructive sleep apnea and incidence of all-type cancers: a systematic review and meta-analysis.

Obstructive sleep apnea (OSA) is one of the most common sleep-related breathing disorders and is featured by complete or partial obstruction of the upper airway using sleep. Conflicting reports regarding the association between obstructive sleep apnea (OSA) and cancer incidence are existing in different studies. The aim of this study is to determine whether OSA is independently associated with incidence of all-type cancers by using the meta-analysis. Medline, Embase, PubMed, Ovid, the Cochrane Library database, Web of Science, and Google Scholar were searched by two independent reviewers until 31 January 2021. Studies that evaluated OSA and the cancer incidence were included. Pooled risk ratios (RR) and corresponding 95% confidence intervals (CI) were calculated. Twelve studies, involved 184,915 participants, were pooled in this meta-analysis. Fixed-effects model analysis showed that patients with OSA had an increased risk of cancer incidence (RR: 1.52, 95% CI: 1.39-1.66, P < 0.001). The subgroup analysis showed that the pooled RRs of cancer incidence were 1.14 (95% CI: 1.04-1.25, P = 0.006) for mild OSA, 1.36 (95% CI: 1.32-1.92; P < 0.001) for moderate OSA and 1.59 (95% CI: 1.45-1.74; P < 0.001) for severe OSA, respectively. Patients with moderate and severe OSA were identified to have an increased risk of cancer incidence when compared to patients with mild OSA. In addition, patients with severe OSA also showed an increased risk of incident cancer (RR: 1.18, 95% CI: 1.08-1.28, P < 0.001) when compared to patients with moderate OSA. In conclusion, from most updated literatures, our meta-analysis results indicated that OSA was independently associated with incidence of all-type cancers when stratified the severity of OSA. However, further detailed analysis and clinical studies are warranted to decipher the association between OSA and cancer prevalence.