P022 Obstructive sleep apnoea and cancer risk: preliminary results of a case-control analysis using data from the Cancer Lifestyle and Evaluation of Risk Study (CLEAR) study

INTRODUCTION: Animal and cellular models suggest that obstructive sleep apnoea (OSA) plays a role in the development of cancer. Epidemiological studies have found inconsistent associations and typically lack control for lifestyle risk factors contributing to both OSA and cancer. We examined associations between OSA and common cancers in a case-control study. METHODS: We analysed data from the New South Wales CLEAR Study which recruited adults with newly diagnosed cancer (n=8551 cases) and cancer-free controls (n=2230). Self-reported OSA was compared in women and men with a verified cancer diagnosis and controls of the same gender. Covariates included age, body mass index, smoking, passive smoking, alcohol intake, physical activity, skin colour, and time spent outdoors. RESULTS: OSA was more common in cancer cases than controls: 2.9% vs. 1.9% in women and 7.9% vs. 5.9% in men. For women, OSA was not significantly associated with melanoma (AOR 1.58, 95% CI 0.76-3.29), lung (1.54; 0.59 - 3.99), breast (1.35; 0.79-2.31), or bowel cancer (1.26, 0.61 - 2.59) after adjustment for potential confounders. For men, OSA was not significantly associated with bowel (1.37; 0.92-2.03), prostate (1.31; 0.94 -1.82), lung (0.96; 0.45-2.01), or melanoma (0.92; 0.58-1.48) after control for covariates. DISCUSSION: Further analysis will consider rarer cancers and the role of shiftwork, sleep duration, and napping. Preliminary results support a link between OSA and common cancers only through shared risk factors. Information on OSA treatment is missing from this study. OSA treatment together with self-reported OSA may lead to under-estimation of any OSA-cancer association.