Several population-based studies across various geographical regions and ethnic groups have established a high prevalence of OSA. This epidemic of OSA is closely related to the obesity epidemic—an important public health related condition facing adults globally. In the United States in 2004, the estimated prevalence of adult obesity, classified as a body mass index (BMI) over 30 kg/m2, was more than 30% and the prevalence of extreme obesity (BMI > 40 kg/m2) was 2.8% in men and 6.7% in women [1]. Associated health care expenditures in obese individuals is 36% higher than normal weight persons, and it has been estimated that up to 7% of the annual health care expenditures is related to obesity [2,3]. Obesity is a well-recognized risk factor for a variety of medical conditions such as OSA, type 2 diabetes, cardiovascular diseases, hyperlipidemia, metabolic syndrome, and nonalcoholic fatty liver disease.