Sleep quality and effects of position on sleep apnea in East Asian children § Hyo Yeol Kim, Hun-Jong Dhong * , Jae-Kwon Lee, Seung-Kyu Chung, Soo-Chan Jung Department of Otorhinolaryngology – Head and Neck Surgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea Received 21 February 2010; accepted 20 July 2010 Available online 30 August 2010 Abstract Objectives: To assess whether obstructive sleep apnea syndrome (OSAS) affects sleep architecture and quality in East Asian children, and also to assess the effects of body position during sleep on respiratory disturbance during sleep. Materials and methods: We enrolled 50 consecutive East Asian children with habitual snoring between 2007 and 2009. Nineteen children had OSAS (apnea-hypopnea index, AHI  5; OSAS group) and 31 children were simple snorers (control group). They underwent polysomno- graphy and physical examination of their nasal and oral cavities with a roentgenogram of the nasopharynx. Sleep architecture and other polysomnographic variables were compared between the OSAS and control groups. The effect of body position during sleep on respiratory disturbance was examined, and also in relation to obesity and adeno-tonsillar size. Results: There was a decrease in total sleep time and in sleep efficiency, as well as increased arousal and heart rate (P < 0.05) in the OSAS group. Sub-analysis of AHI according to sleep posture showed that AHI is higher when the patient is in the supine position than in the non- supine position (P = 0.032). The presence of OSAS and kissing tonsils were contributing factors to the positional difference in AHI (P < 0.05). Obesity and adenoid hypertrophy did not affect the positional difference of AHI. Conclusions: OSAS may have a greater influence on the sleep architecture of East Asian children, and East Asian children may have a higher AHI when sleeping in the supine position. Tonsillar hypertrophy and the presence of OSAS are possible contributing factors for positional difference of AHI in East Asian children. # 2010 Elsevier Ireland Ltd. All rights reserved. Keywords: Sleep apnea; Sleeping position; Children; Polysomnography; Obesity; Tonsil; Adenoids 1. Introduction Recently, there has been increasing recognition of the significance of childhood obstructive sleep apnea syndrome (OSAS), with various lines of evidence regarding the consequences of the disorder [1]. The criteria used to identify OSAS differ for adults and children, with the current criteria for pediatric OSAS largely based on those outlined by Marcus et al. [2–6]. However, substantial discrepancies in the results of several studies demonstrate distinctions between the clinical characteristics of pediatric OSAS as compared to adult OSAS. Overall sleep architecture is preserved in children with OSAS [7], unlike adult OSAS. Furthermore, sleeping in the supine position usually worsens apnea in adults [8,9], but body position does not influence the frequency or severity of respiratory events in children [10,11]. These studies have primarily been performed in Western countries. However, the clinical characteristics of OSAS differ by ethnicity [12,13], with subjects of East Asian descent more likely to report snoring than subjects of European descent [14,15]. www.elsevier.com/locate/anl Auris Nasus Larynx 38 (2011) 228–232 § This was presented at the 15th Combined Congress of Otorhinolaryn- gology-Head and Neck Surgery, Kyung-Ju, Kyungsangbuk-do, Republic of Korea (23–24 October 2009). * Corresponding author at: Department of Otorhinolaryngology – Head and Neck Surgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, Irwon-dong 50, Gangnam-gu, Seoul 135-710, Republic of Korea. Tel.: +82 2 3410 3579; fax: +82 2 3410 3879. E-mail addresses: hjdhong@skku.edu, siamkhy@skku.edu (H.-J. Dhong). 0385-8146/$ – see front matter # 2010 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.anl.2010.07.005