The Effect of the Mediterranean Diet on Obstructive Sleep Apnoea-Hypopnoea Syndrome: A Randomised Trial

Obstructive sleep apnoea-hypopnoea syndrome (OSAHS) is considered to be one of the most prevalent sleep-related breathing disorders, with an enormous effect on public health. Approximately 2-4% of the general adult population experiences some degree of this syndrome. This percentage increases even more with obesity, up to 20-40%, especially in individuals with an excessive body mass index (BMI) > 30 kg/m2. OSAHS is associated with significant systemic consequences, including cardiovascular morbidity and mortality, and the risk increases with the severity of the syndrome. The pathophysiology underlying the link between OSAHS and the cardiovascular system is attributed largely to systemic inflammation and oxidative stress, which are both contributors to endothelial dysfunction. The treatment modalities of OSAHS include continuous positive airway pressure (CPAP), weight loss, upper airway surgery, and medication. CPAP is the first line therapy, as a means of maintaining upper airway patency, and it is well known that this intervention reduces morbidity and mortality. In severe cases of OSAHS the weight loss strategy is essential and must accompany CPAP treatment. A growing body of evidence in OSAHS supports the beneficial role of weight reduction, induced by diet alone or in combination with exercise, leading to a reduction in apnoeas and hypopnoeas.We aim to evaluate the effect of the Mediterranean diet compared with that of a prudent diet on obese OSAHS patients who were treated with CPAP while receiving counselling to increase their physical activity.

Inclusion criteria

• Patients with apnoea-hypopnoea index >15/h and Epworth Sleepiness Scale > 10

Exclusion criteria

• Diseases such as ischaemic heart disease, diabetes mellitus, thyroid disorders, and malignancies
• Upper airway surgery
• Gestation
• Alcoholism
• Diet for weight reduction during the last 6 months
• Eating habits close to the Mediterranean diet at the entry phase
• Intake of antioxidant supplements
• Medications affecting weight
• Smoking (in the case of TBARS)
• Therapy with sleeping pills
• Use of anti-depressive medication
• BMI < 30.0 Kg/m2