Association between sleep-disordered breathing, obstructive sleep apnea, and cancer incidence: A systematic review and meta-analysis

Objective/background: Via this systematic review and meta-analysis, we assessed the associatio between sleep-disordered breathing (SDB)/obstructive sleep apnea (OSA) and cancer incidence. Method: Medline, Embase, Cochrane Central, and electronic databases were searched for relevant studies in any language. Studies were included based on the following criteria: (1) those on patients with SDB/OSA, (2) those reporting cancer incidence rates specific to patients with SDB/OSA, and (3) those defining SDB/OSA using sleep-study-based objective measures. The quality of the included studies was assessed using the Newcastle-Ottawa Quality Assessment Scale (NOQA). Results: Of the 8766 retrieved citations, five studies that defined SDB/OSA using the apnea-hypopnea index (AHI) or the respiratory disturbance index (RDI) totaling 34,848 patients with SDB and 77,380 patients without SDB were pooled into a meta-analysis. All five studies were of good quality (NOQA ≥ 6). A total of 574 (1.6%) and 290 (0.37%) incident cancers were reported in patients with and without SDB, respectively. In the unadjusted analysis, patients with SDB/OSA were at an increased risk of incident cancer (relative risk [RR]: 1.53, 95% confidence interval [CI]: 1.31-1.79, P <0.001, I²: 0, five included studies). When adjusted for traditional cancer risk factors, the association between SDB/OSA and cancer incidence, although attenuated (RR: 1.40, 95% CI: 1.01-1.95, P = 0.04, I²: 60%, five included studies), remains significant. Conclusions: SDB/OSA may increase the risk of incident cancer. Inferring an independent association is not possible from our analysis considering the retrospective cohort design of the included studies and high inter-study heterogeneity. An individual patient data meta-analysis would help validate our findings.