[Sleep apnea syndrome and obesity]

Obesity is a main risk factor for sleep apnea syndrome (SAS). The prevalence of SAS is especially high in massive obesity and in visceral obesity. The mechanisms of obstructive apneas in obesity are poorly known, but an increase in upper airway collapsibility probably plays an important role. Several cardiorespiratory complications of SAS, especially systemic arterial hypertension, diurnal alveolar hypoventilation and pulmonary arterial hypertension, are more frequent and more severe in obese patients. An important weight loss resulting from surgical treatment of obesity is often associated with a dramatic decrease in apnea-hypopnea index in patients with massive obesity. In patients with moderate obesity, dietary weight loss is associated with varying degrees of improvement in SAS. Pharyngoplasty and anterior mandibular positioning devices have a low success rate in patients with massive obesity. Nasal continuous positive airway pressure is often the only effective treatment in obese SAS patients.