Snoring and obstructive sleep apnea in Thai school-age children: prevalence and predisposing factors

We studied the prevalence of habitual snoring and its associations with tonsillar size, allergic rhinitis, obesity, and parental smoking, as well as prevalence of obstructive sleep apnea (OSAS) in a sample of 1,142 children aged 6-13 years (mean, 7.25 +/- 0.58) from seven randomly selected schools in Hat yai, Southern Thailand. Eighty-five (8.5%) of the children were habitual snorers; the prevalence was the same in boys and girls. Significant and independent association was present between snoring and allergic rhinitis with an odds ratio of 5.27 (95% CI, 1.57-17.77). The odds ratio was significantly increased to 2.65 (CI, 1.31-5.39), 5.72 (CI, 2.67-12.25), and 11.06 (CI, 1.91-63.84) in children with tonsillar size of 2+, 3+, and 4+, respectively. Of the 85 habitual snorers, 69 could be contacted by telephone call or by hospital visit. Eight of these were reported to have at least one of the following symptoms: difficulty breathing during sleep, stop breathing at night, restless sleeping and frequent awakening, sleeping with the head tipped back, and a tendency to breathe through the mouth rather than the nose. Polysomnographic studies in these 8 children demonstrated an apnea/hypopnea index of 0.6-4.7 per hr. Seven children met the criteria for OSAS. Thus, our estimate of the prevalence of OSAS among Thai schoolchildren was 7/1,008 (0.69%). We have shown that the prevalence of habitual snoring was 8.5%, and the prevalence of OSAS in a sample of Asian school-age children in Southern Thailand was 0.69%, which was similar to that observed in Western populations. An association of snoring with tonsillar size or allergic rhinitis was demonstrated. All but one of the snoring children with sleep-related symptoms had OSAS, but all were mild cases.