Table 1.

Study Inclusion and Exclusion Criteria

Inclusion criteria	Exclusion criteria
• T2DM (verified by primary care provider or medication typically ordered for diabetes)	• Diagnosis of another sleep disorder, in addition to OSA, based on PSG (e.g., periodic limb movement disorder ≥ 10 limb movements/hr, or insomnia)
• AHI (from PSG) greater than ≥ 10	• Oxygen or Bi-level positive airway pressure required for treatment of OSA
• A1C< 9.0%	• Oxygen saturation <75% for >10% of the diagnostic PSG or if subject has oxygen saturation <75% for >25% of the first 4 h of the diagnostic PSG
• ESS ≥ 10 (Screening)	• Any individual in the household currently or with history of CPAP treatment
• Able to ambulate independently or with a cane	• Type 1 or gestational diabetes
• Age 30 years or older	• Prescribed insulin for treatment of T2DM
• No acute medical and psychiatric illness in past 3 months	• Changes in diabetic medications in prior 3 months
• Self-reported sleep duration of at least 6 hours by baseline Sleep/Activity Diary	• Regular use (> 3 times/week) of hypnotic or alerting medications (i.e. modafinil)
• Telephone access	• Prior treatment for OSA with CPAP or surgery
• Able to perform study tests (e.g., speak, read and write in English).	• History of a near-miss or automobile accident due to sleepiness
• Willing to be randomized to CPAP or sham-CPAP	• Employed in transportation-related safety sensitive (i.e. airline pilot, truck driver, or train engineer)
	• Currently working night or rotating shifts
	• Routine consumption of alcohol as determined by >2 drinks day
	• Claustrophobia that prevents wearing the CPAP mask
	• Pregnancy

T2DM= type 2 diabetes mellitus; AHI= apnea + hypopnea index; ESS= Epworth Sleepiness Scale; CPAP= continuous positive airway pressure, OSA= obstructive sleep apnea; PSG= polysomnography