CLINICAL REVIEW Influence of asthma on sleep disordered breathing in children: A systematic review Pablo E. Brockmann * , Pablo Bertrand, Jose A. Castro-Rodriguez Department of Pediatrics, School of Medicine, Pontificia Universidad Catolica de Chile, Chile article info Article history: Received 26 November 2013 Received in revised form 28 January 2014 Accepted 29 January 2014 Available online xxx Keywords: Apnea Sleep Snoring Wheezing Children summary The objective of this study was to perform a systematic review for the association between asthma and sleep disordered breathing (SDB) in children. We performed an electronic search in Medline, Embase, CINAHL, LILACS and Cochrane databases. Study selection criteria: children <18 y of age with diagnosis of asthma and SDB. Primary outcomes: odds ratios (OR) and 95% confidence intervals [95%CI] of asthma for SDB were calculated. There were n ¼ 968 citations identified, of them n ¼ 17 studies were selected, which included n ¼ 45 155 (53% males) children. All included studies defined asthma and SDB based on questionnaires, and only two performed a sleep study for diagnosing obstructive sleep apnea. Mean age was 8.6  2.5 y. SDB was significantly more frequent in children with asthma compared with non- asthmatics: 23.9% vs 16.7% respectively, p < 0.0001. Children with asthma had a significantly higher risk for SDB: OR 1.9 [1.7; 2.2]. This systematic review showed evidence of a significant association be- tween asthma and SDB in children. Asthma seems to be a significant risk factor for developing SDB. However, the minority of the studies based the diagnosis of SDB on polysomnography, considered the current gold standard for SDB. The physiological and temporal relationships between both conditions should be addressed in future cohort studies. Ó 2014 Elsevier Ltd. All rights reserved. Introduction Asthma is among the most prevalent chronic diseases in chil- dren [1]. The prevalence of asthma has rapidly increased worldwide over the last decades [2]. Similarly to the increase of the prevalence of asthma, snoring and sleep disordered breathing (SDB) have also increased reaching similar prevalence than asthma [3]. On the other hand, upper and lower airway inflammation is related to allergic diseases like rhinitis and asthma, and the release of inflammatory molecules [4]. Among these inflammatory medi- ators, cystenil leukotrienes have been identified in asthma [5] and also SDB [6]. Furthermore, the presence of cystenil leukotrienes seems to play an important role in the development of adeno- tonsillar hyperplasia that is one of the leading factors for devel- oping SDB [7]. This similar increase in prevalence and the fact that both are diseases that are associated with a common inflammation of the airway [8], have led to the search of an association between asthma and SDB [9]. Although there have been attempts to demonstrate an association between asthma and SDB in children, there has been no state of the art systematic review to support this potential associ- ation. Therefore, we performed the present systematic review in order to analyze all available evidence for an association between asthma and SDB in children. Methods Search and selection criteria We developed individual search strategies for each of the following bibliographic databases: Medline (1950epresent), Embase (1988epresent), CINAHL (1982epresent), and LILACS (1986epresent). The strategy used several combinations of searches concerning following keywords: asthma OR wheezing AND sleep apnea OR snoring OR sleep disordered breathing. We applied also individual limits for detecting only studies on subjects Abbreviations: OR, odd’s ratio; SDB, sleep disordered breathing; SD, standard deviation; ISAAC, international study on asthma and allergies in childhood; PEF, peak expiratory flow; PSQ, pediatric sleep questionnaire; RSV, respiratory syncytial virus. * Corresponding author. Lira 85, 5to Piso, 8330074 Santiago, Chile. E-mail address: pbrockmann@med.puc.cl (P.E. Brockmann). Contents lists available at ScienceDirect Sleep Medicine Reviews journal homepage: www.elsevier.com/locate/smrv http://dx.doi.org/10.1016/j.smrv.2014.01.005 1087-0792/Ó 2014 Elsevier Ltd. All rights reserved. Sleep Medicine Reviews xxx (2014) 1e5 Please cite this article in press as: Brockmann PE, et al., Influence of asthma on sleep disordered breathing in children: A systematic review, Sleep Medicine Reviews (2014), http://dx.doi.org/10.1016/j.smrv.2014.01.005