Prevalence of sleep apnoea syndrome in the Spanish adult population

Background. Some data indicate that obstructive sleep apnoea syndrome (OSAS), a disorder characterized by recurrent episodes of cessation of respiratory airflow during sleep, is highly prevalent in the general population but no such data exist in southern Europe, Methods. In the Zaragoza metropolitan area (northeast of Spain) a representative sample of 1360 subjects aged >18 years and selected by quota methods according to age, sex and geographical distribution agreed to participate. Trained interviewers visited selected residents to administer a sleep questionnaire in the presence of a bedmate or another closely-related person who lived in the subject's home; anthropometric data and arterial blood pressure were also recorded. All participants were invited to record nocturnal home oximetry (NHO). The NHO results were classified as 'abnormal' (or consistent with OSAS) in the presence of repetitive, short-duration arterial oxyhaemoglobin saturation (SaO2) fluctuations, Results, The diagnosis of OSAS was established in subjects with loud (severe) snoring + excessive daytime sleepiness + abnormal oximetry. In the group of 1222 subjects (597 males, 625 females) who agreed to have NHO, 63.7% of men and 36.3% of women snored 'usually' or 'always' (severe snorers); daytime sleepiness in active situations occurred in 12.1% and 14.4% respectively. The association of severe snoring plus daytime sleepiness plus abnormal NHO was found in 18 subjects (13 males, 5 females). Conclusions. We estimated that among Spanish adults, 0.8% of women and 2.2% of men meet the minimal criteria to diagnose sleep apnoea syndrome.