Obstructive Sleep Apnea (OSA) is associated with increased oxidative stress. The major sources of Reactive Oxygen Species (ROS) in the vasculature are the NADPH oxidases. Several polymorphisms related to NADPH oxidase expression or NADPH oxidase activity has been identified. The investigators are going to compare the distribution of the allelic frequencies of A-930G and C242T polymorphisms and their possible relationship with the levels of 8-isoprostanes as a marker of oxidative stress in patients with OSA and in a control group without OSA.

DESIGN: CASE-CONTROL STUDY METHODS: We are going to determine the A-930G and C242T p22phox genotypes in patients with OSA and healthy subjects recruited from sleep unit of Son Dureta University Hospital, (Palma de Mallorca, Spain). 8-Isoprostane is going to be measured as an oxidative stress marker with an 8-isoprostane EIA kit (Cayman Chemicals Company, USA) in plasma samples.

Inclusion Criteria:Polyysomnografic study with Apnoea/Hypoapnoea Index higher to 10 in patients and lower in controls.

Exclusion Criteria:

• chronic obstructive pulmonary disease, liver cirrhosis, thyroid dysfunction, rheumatoid arthritis, chronic renal failure and/or psychiatric disorders.

patients with OSAS defined by an apnea hypopnea index (AHI)>10 h-1 will be included in the study along with control subjects without OSAS. Participants were consequently studied at the sleep unit of Hospital Universitario Son Dureta, (Palma de Mallorca, Spain).