Obstructive sleep apnea and cancer- A nationwide epidemiological survey

Background. Several epidemiological studies have reported an increased cancer incidence among subjects with obstructive sleep apnea (OSA) and in animal models intermittent hypoxia has been related to markers of cancer activity. Aims. To report nationwide data on the prevalence and incidence of cancer among all diagnosed Icelandic OSA patients (total population 320,000) Methods. Altogether 8.833 Icelanders 20 years and older (6311 males and 2522 females) had ever been diagnosed with clinically significant OSA from 1987 until December 2014. All subjects ever diagnosed with cancer in this group until 2014, were identified in the Icelandic cancer register. Standardized incidence ratio (SIR) was estimated. Results. The average age at OSA-diagnosis for males and females was 52.8 and 56.2 years, and for incident cancer 68.1 and. 66.6 years, respectively Among the OSA patients altogether 512 had been diagnosed with cancer when they were diagnosed with OSA. In the 88.542 person years of follow-up after OSA diagnosis there were 869 incident cancer cases (10.4) The most common incident cancer in females was breast cancer (n=68, 28%) and prostate cancer in males (n=200, 32%). OSA patients with cancer had similar body mass index, OSA severity and age at OSA diagnosis as those not diagnosed. In the ongoing age and gender specific risk analysis subjects under 65 years of age were at increased cancer risk (SIR: 1.2(1.1;1.3)), especially melanoma that accounted for 3% of incident cases in females and males (8/19 cases, SIR: 2.2(1.2;4.10) and 3.2(1.5;6.7),respectively) Conclusions. Nationwide Icelandic data show that OSA has a moderate risk association with some cancer types among subjects less than 65 years of age.