NEW YORK (Reuters Health) - People with mild to moderate sleep apnea may benefit more from breathing pressurized air via a facemask at night than from wearing an oral device while they sleep, Chinese researchers report.

In addition, losing weight seems to improve disordered breathing during sleep, but most people can't ease the problem sufficiently with weight loss alone, according to the report in the medical journal Thorax.

Sleep apnea is a condition in which tissues in the airway passages collapse and block breathing for brief but frequent periods while a person sleeps. It's usually diagnosed in a sleep lab, where people can be observed and monitored while they sleep. People with sleep apnea usually suffer from excessive sleepiness during the day and are prone to develop high blood pressure and heart disease.

Treatment is often provided by "continuous positive airway pressure" or CPAP; this uses a machine to deliver pressurized air via a mask, thus preventing the airways from becoming blocked. Another approach is to fit the patient with an oral appliance that holds the lower jaw in such a position that the throat is kept open during sleep.

In the current study, Dr. Mary S. M. Ip and colleagues from The University of Hong Kong compared these two strategies with conservative measures over a 10-week period in 101 patients with mild to moderate sleep apnea.

The conservative measures included general advice on sleep behaviors and, if overweight, referral to a weight control program. For those assigned to CPAP, the air pressure was delivered at a pre-set level. For the others, a non-adjustable oral appliance was tailor-made for each individual by an orthodontist.

CPAP improved obstructed breathing better than the oral appliance, which, in turn, improved breathing better than conservative measures alone, the researchers report. Moreover, CPAP was associated with significantly better relief from daytime sleepiness.

Compared with the other treatments, CPAP significantly improved pain symptoms and physical functioning assessed by a standardized health-related questionnaire.

On another standardized questionnaire about quality of life in relation to sleep apnea, CPAP and the oral appliance were comparable in their ability to improve scores over and above that seen with conservative measures alone.

Both active treatments significantly reduced morning blood pressure to a similar extent.

Consistent with previous reports, sleep apnea improved when participants lost weight -- but only about 10 of them were able to minimize the breathing problem with weight loss alone.

Summing up, the researchers conclude: "CPAP produced the best improvement in terms of physiologic, symptomatic, and health-related quality-of-life measures, while the oral appliance was slightly less effective."