Repetitive airway occlusion during sleep in patients with obstructive sleep apnoea (OSA) results in the generation of negative intrathoracic pressures and ends in arousal, both of which may predispose to reflux during sleep (nocturnal reflux). We aimed to determine and compare the prevalence of nocturnal reflux symptoms and their sleep-associated risk factors in untreated OSA patients, OSA patients using continuous positive airway pressure (CPAP) therapy, and the general population. Gastro-oesophageal reflux and sleep questionnaires were completed by 1116 patients with polysomnography diagnosed OSA and by 1999 participants of the 2007 Busselton population health survey. Of the OSA patients, 137 completed the reflux questionnaire before and after treatment. Risk of OSA in the general population was assessed using the Berlin score. The prevalence of frequent (>weekly) nocturnal reflux symptoms was increased (P<0.001) in OSA patients (10.2%) versus the general population (5.5%), in individuals from the general population at high (8.7%) versus low risk (4.3%) of OSA and in patients with severe (13.9%) versus mild OSA (5.1%). Frequent nocturnal reflux symptoms were associated with high risk (general population) (OR 1.9, P<0.01) and severity of OSA (OSA population) OR 3.0, severe versus mild OSA, P<0.001) after correcting for age, gender and body mass index. Treatment with CPAP decreased the prevalence of reflux symptoms significantly. In conclusion, the prevalence of nocturnal reflux symptoms is increased in those with or suspected of having OSA. This association is independent of other risk factors including age, gender and body mass index, suggesting a causal relationship between OSA and nocturnal reflux.
© 2010 European Sleep Research Society.