To Örebro University

Background: Nocturnal hypoxia in obstructive sleep apnea (OSA) is a potential risk factor for cancer disease but data are conflicting. We aimed to investigate the association between OSA measures and cancer prevalence in a large national OSA patient cohort.

Methods: Population-based, cross-sectional study on patients initiating CPAP therapy between July 2010 and March 2018 in Sweden (n=62,811), with crosslinked data from the National Cancer Registry and socio-economic data from Statistics Sweden. After propensity score matching for anthropometric data, comorbidities, socio-economic status, smoking prevalence, the association between all-cause and subtype cancer diagnosis 5 years prior to start of PAP treatment and sleep apnea severity, measured as apnea hypopnea index (AHI) or oxygen desaturation index (ODI), was analyzed using chi2-tests.

Results: 2,093 OSA patients with cancer (age 65.3±10.1 years, BMI 30 (IQR 27-34) kg/m2, 29.8% females) had higher AHI (32 (IQR 20-50) versus 30 (19-45), event/hour, p=0.002) and ODI (28 (17-46) versus 26 (16-41) events/hour, p<0.001) when compared with matched OSA patients without cancer. Subgroup analysis confirmed that ODI was significantly higher in OSA patients with lung cancer (38 (21-61) versus 27 (16-43), p=0.012, N=57), prostate cancer (28 (17-46) versus 24 (16-39), p=0.005, N=617), and malignant melanoma (32 (17-46) versus 25 (14-41), p=0.015, N=170).

Conclusion: OSA mediated intermittent hypoxia was independently associated with cancer in this large, national cohort. Future longitudinal studies are warranted to study the potential influence of OSA treatment on cancer incidence.