Snoring, apneic episodes, and nocturnal hypoxemia among children 6 months to 6 years old : an epidemiologic study of lower limit of prevalence

To identify a lower limit of the prevalence of sleep-related breathing disturbances among preschool children. A cross-sectional epidemiologic study in two stages, first by questionnaires and second by whole-night investigation of children symptomatic of the sleep apnea syndrome. Gardabaer, a small town, 10 km south of Reykjavìk, Iceland. All children in Gardabaer, 6 months to 6 years old (n = 555). Symptom score estimated by questionnaire and respiratory events based on overnight oximetry, thermistors, and a static charge sensitive bed. The response rate was 81.8%. Snoring was reported as often or very often among 14 (3.2%) and occasionally by 73 (16.7%). Apneic episodes were reported often or very often among seven (1.6%). Altogether 18 children were highly suspected of the sleep apnea syndrome because of habitual snoring or apneic episodes. The girls (n = 9) were older than the boys (mean age: 46 +/- 21 months vs 20 +/- 12 months, p < 0.001). Eventually 11 children came for a whole-night investigation and 8 of them showed more than three respiratory events per hour of sleep, associated with > or = 4% oxygen desaturation. The lower limit of the sleep apnea syndrome prevalence among these children was thus 2.9% (SE, 0.5%). Among children, symptoms such as snoring and apneic episodes are reported relatively seldom, but a high proportion of the children with these symptoms have hypoxic respiratory events.