Table 3.

Selected clinical studies relevant to OSA and obesity^a

Type	Methods	Findings	Author
Weight history	1-year weight histories in newly diagnosed OSA patients vs. screened controls	OSA patients exhibited significant antecedent weight gain	Phillips et al. 1999
	Obese newly diagnosed OSA subjects maintained lifestyle and dietary logs	Subjects reported rapid weight gain and adverse food intake profiles	Traviss et al. 2002
CPAP effects	OSA subjects with BMI>25 treated with CPAP for 6 months; compliance and body weight measured	CPAP-compliant subset more likely to lose >4.5 kg	Loube et al. 1997
	Retrospective comparison of BMI in compliant vs. noncompliant CPAP users for 1 year	CPAP did not induce weight loss	Redenius et al. 2008
	OSA subjects had visceral and subcutaneous fat, BMI, and leptin assessed (by CT scan) before/after CPAP for 3 days or 6 months	CPAP decreased leptin and visceral fat in all subjects; only those that lost weight also showed less subcutaneous fat	Chin et al. 1999
Metabolic rate	Sleeping metabolic rate in OSA subjects before/after uvuloplasty	Moderate-severe OSA increased metabolic rate, decreased by uvuloplasty	Lin et al. 2002
	24-hr metabolic rate in OSA subjects vs. snorers, 3 mo. before/after CPAP	OSA increased 24-hr metabolic rate, decreased by CPAP	Stenlof et al. 1996
	24-hour metabolic rate in male OSA subjects divided into quartiles of hypoxemia	More severe hypoxemia predicted lower metabolic rate	Major et al. 2007
Leptin	Leptin levels of male OSA subjects vs. BMI-matched controls	OSA associated with increased leptin	Phillips et al. 2000
	Leptin levels of male OSA subjects vs. BMI-matched controls	OSA associated with increased leptin	Vgontzas et al. 2000
	Leptin levels of male OSA subjects related to AHI and anthropometric data	No association between AHI and leptin	Schafer et al. 2002

^aAHI, apnea-hypopnea index; BMI, body mass index; CPAP, continuous positive airway pressure; CT, computed tomography; OSA, obstructive sleep apnea