Metabolic and Neurobiological changes after Continuous Positive Airway Pressure treatment for Obstructive Sleep Apnea

Blinded Continuous Positive Airway Pressure for 12 weeks followed by open-label CPAP treatment for 12 weeks. The subjects will undergo a 3 night home-titration using an auto-titrating machine. The machine will then be set to the 90th percentile on a fixed pressure for the remainder of the study. We are using an identical Sham machine. A trained CPAP technologist who had been involved in other similar sham-controlled trials is responsible for the allocation of the CPAP machines for this and all other studies. Only this person has access to the sham machines, which she stores separately from the effective CPAP machines. This person will have no direct contact with the subjects. This is a 24 week study. For the first 12 weeks of the study, Week 0 to Week 12, the subject is randomised to use either therapeutic CPAP or sham CPAP every night for the entire 12 weeks. This first 12 weeks is blinded. From Week 12 to Week 24 every subject is changed to receive open-label therapeutic CPAP every night for the entire 12 weeks. They will return the blinded machine they used from Week 0 to Week 12 and will receive a new therapeutic machine.