Obstructive sleep apnea is defined as a repetitive collapse of the pharynx during sleep (Malhotra, et al. 2012) which cases intermittent hypoxia. Snoring, witnessed apnea, fatigue and morning headache are symptoms of the disease which has severe health effect (Malhotra. et al. 2012) including increased mortality risk (Ensrud. et al. 2012) and effects on quality of life (Kuhn. et al. 2017).

Obesity, male sex and age are all risk factors for obstructive sleep apnea (Schwartz. et al. 2010, Edwards. et al. 2010) . Bariatric surgery is known to be a good treatment to achieve a sustained weight loss but the long term effects of bariatric treatment of obstructive sleep apnea is not well studied. The aim of this study is therefore to study the long effects of bariatric surgery as a treatment for obstructive sleep apnea and to find predictors that can be used to predict the severity of the disease.

Obstructive sleep apnea is defined as a repetitive collapse of the pharynx during sleep (Malhotra, et al. 2012) which cases intermittent hypoxia. Snoring, witnessed apnea, fatigue and morning headache are symptoms of the disease which has severe health effect (Malhotra. et al. 2012) including increased mortality (Ensrud. et al. 2012) and effects on quality of life (Kuhn. et al. 2017). Hence, identifying and treat obstructive sleep apnea are important.

Obesity, male sex and age are all risk factors for obstructive sleep apnea (Schwartz et. al. 2010, Edwards. et. al. 2010) . Bariatric surgery is known to be a good treatment to achieve a sustained weight loss but the long term effects of bariatric treatment of obstructive sleep apnea is not well studied. The aim of this study is therefore to study the long effects of bariatric surgery as a treatment for obstructive sleep apnea and to find predictors that can be used to predict the severity of the disease.

Eighty-six patients with obesity have been recruited at the Catholic University hospital in Rome, Italy during 2012 when patients were enrolled during their evaluation for bariatric surgery. At baseline, the patient underwent fasting blood chemistry, anthropometric measurements and overnight polysomnography. The patients also underwent a 3 hour oral glucose tolerance test in order to determinate glucose tolerance (normal glucose tolerance, impaired glucose tolerance and type 2 diabetes mellitus). Patient then received treatment with bariatric surgery (gastric sleeve, biliopancreatic diversion or gastric bypass) during 2012-2013 or decided not to undergo bariatric surgery.

Patient will undergo follow-up during 2016-2017 where fasting blood chemistry, anthropometric measurements and overnight polysomnography will be assessed. The patient will also undergo a 3 hour oral glucose tolerance test.

The effects of bariatric surgery on obstructive sleep apnea will then be evaluated. Differences in the treatment effect between the different bariatric surgical procedures will be studied. Patients characteristics at baseline, such as weight, height, BMI and components of the metabolic syndrome and their association to the severity of obstructive sleep apnea will be studied in order to find predictors for the severity of the disease.

Inclusion Criteria:

• BMI above 30 kg/m2
• Age between 20 and 70 years
• Willingness to understand the protocol and willingness to participate in the study

Exclusion Criteria:

• Exclusion criteria is severe co-morbidities that would prevent the patients to undergo bariatric surgery. Such as severe anemia, severe heart failure, active or previous malignancies the last 5 years. Myocardial infarction or unstable angina pectoris the last 6 months. Pregnancy. Suspected poor compliance. Drug or alcohol abuse. Major gastrointestinal disease.
• Inability to undergo polysomnography.