Obesity and sleep-disordered breathing--when two 'bad guys' meet.

Sleep-disordered breathing (SDB), in particular obstructive sleep apnoea (OSA) and obesity hypoventilation syndrome (OHS) are associated with significant morbidity and mortality. The prevalence of these conditions is rapidly rising mainly due to the worldwide increase in obesity. Obesity contributes to the pathogenesis of SDB in multiple ways including altering upper airway anatomy and collapsibility, ventilatory control and increasing respiratory work load. There is also increasing evidence that OSA itself contributes to the development of obesity. Moreover, both OSA and obesity promote the activation of inflammatory pathways, which is likely a key mechanism in cardiovascular and metabolic disease processes. Early recognition of SDB is important as effective treatments are available. Public health measures to reduce the prevalence of obesity are urgently required to halt the increasing burden of SDB.