This study evaluates epigenetics in morbid obese patients who are waiting for bariatric surgery. A home cardiopulmonary polygraphy is performed to evaluate for the presence of sleep-disordered breathing. The principal investigator make the decision of starting CPAP among patients with obstructive sleep apnea according to current clinical guidelines. One year follow up after bariatric surgery will be performed. A total of 5 visits will be scheduled: two of them before bariatric surgery and 3 after (3, 6 and 12 months).

At every visit, all patients had: sleep questionaries, blood samples, EKG-Holter and spirometry are collected.

Inclusion Criteria:

• BMI consistently > 40 kg/m2 for 3-5 years, following more than 1 year of unsuccessful controlled medical treatment
• BMI 35-40 kg/m2 with comorbidities associated with morbid obesity (MO) susceptible to improvement with weight loss (high BP, Diabetes, dyslipidemia, OSA, etc.), following more than 1 year of unsuccessful controlled medical treatment.
• A signed informed consent form

Exclusion Criteria:

• Obesity hypoventilation syndrome or treatment with positive pressure devices.
• Diagnosis of systemic inflammatory disease.
• Neoplastic diseases in the last 5 years.
• A cardiovascular event in the last 6 months.
• Pregnancy

Bariatric surgery waiting list in Royo Villanova Hospital