Snoring and nocturnal oxygenation. Is there a relationship?

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.