POSA is associated with increased waist-to-hip ratio in men (Heinzer et al., 2018). This suggests that abdominal obesity in men may induce POSA by pulling up the diaphragm in the supine position, which in turn decreases the tension exerted on the pharyngeal walls through the mediastinum, favouring pharyngeal collapse (Heinzer et al., 2018). In addition, lung volume also plays a role in POSA as a higher positive airway pressure is required to keep the airway open when lung volume is reduced (Heinzer et al., 2005).
Visit the Sleep and Breathing conference 2019 section to learn more about the pathophysiology of POSA. Dr Raphaël Heinzer describes in more detail the effects of obesity, lung volume, upper airway size and head position.