Snoring and nocturnal oxygenation. Is there a relationship?

Abstract

OBJECTIVE: To test the hypothesis that snoring, independently of sleep apnea, is a significant determinant of nocturnal oxygen saturation. DESIGN: Prospective study. SETTING: Sleep disorders clinic, university teaching hospital. PATIENTS: Six hundred twenty-five nonapneic snorers referred to the clinic. METHODS: Nocturnal polysomnography, which included objective and simultaneous measurement of snoring and oxygen saturation, was performed in all patients. Pulmonary function tests and smoking history were also obtained. RESULTS: Multiple stepwise linear regression analysis demonstrated that age, body mass index, and pulmonary function were the most important determinants of nocturnal oxygen saturation, accounting for 20 to 30% of its variability. Snoring was a significant, although weak (partial r2 = 0.073, p < 0.001) determinant of lowest, but not mean, nocturnal oxygen saturation. When mild snorers were matched one-for-one for body mass index to a group of severe snorers, only the lowest, not the mean, nocturnal oxygen saturation was significantly different between the groups. CONCLUSIONS: Snoring is not associated with sustained nocturnal hypoxemia, but it is weakly related to lowest nocturnal oxygen saturation.