Phenotypes of sleep-disordered breathing symptoms to two years of age based on age of onset and duration of symptoms

ObjectiveChildhood sleep-disordered breathing (SDB) symptoms may comprise multiple phenotypes depending on craniofacial anatomy, tonsil and adenoid growth, body habitus, and rhinitis symptoms. The primary objective of this study is to identify and characterize the different SDB phenotypes to two years of age.MethodsData from 770 infants in the Edmonton sub-cohort of the Canadian Healthy Infant Longitudinal Study (CHILD) were analyzed to identify SDB phenotypes based on age of onset and duration of symptoms. Parents completed the 22-item sleep-related breathing disorder (SRBD) scale. Children with a SRBD ratio greater than 0.33 were considered positive for SDB at each quarterly assessment between three months and two years. The STATA Proc trajectory extension identified SDB phenotypes based on their age of onset and duration of symptoms and attributed the percentage chance of a participant being assigned to each phenotype. Multivariate linear regression identified factors associated with increased risk of being assigned to each SDB phenotype.ResultsTrajectory analysis identified four phenotypes: no SDB (65.7%), early-onset SDB (15.7%) with peak symptoms at nine months, late-onset SDB (14.2%) with peak symptoms at 18 months, and persistent SDB (5.3%) with symptoms from 3 to 24 months. Rhinitis was associated with all three SDB symptom trajectories (p < 0.05). Children with gastroesophageal reflux disease presented with early (p = 0.03) and late SDB (p < 0.001). Maternal obstructive sleep apnea syndrome (OSAS) was associated with persistent (p = 0.01) and late SDB (p < 0.001). Atopy (positive skin prick test at one year) was associated with persistent SDB (p = 0.04). Infants born prior to 36.5 weeks gestational age were more likely to present with late SDB (p = 0.03).ConclusionChildhood SDB symptoms, rather than being a homogenous disorder, may comprise multiple overlapping phenotypes each with unique risk factors.     

Frequency of snoring,rather than apnea–hypopnea index,predicts both cognitive and behavioral problems in young children

ObjectivePrimary snoring (PS) and obstructive sleep apnea (OSA) not only affect the quality of sleep in a large number of young children, but have also been repeatedly associated with a variety of behavioral and cognitive problems. However, little is known about the potentially differing relationships of behavioral and cognitive pathology within the sleep disordered breathing (SDB) spectrum.MethodThis study examined data from an enriched for snoring community sample of 631 children aged between 4 and 10 years. Multivariate mixed models were used to assess the relationship between both snoring and the apnea–hypopnea index (AHI). Numerous cognitive and behavioral variables were used, while adjusting for several important demographic variables. These were followed by univariate analyses of individual measures and sensitivity analyses.ResultsResults indicated that snoring status is a significant predictor of general behavioral (p = 0.008) and cognitive (p = 0.013) domains, even after adjusting for baseline covariates and AHI severity. More frequent snoring was associated with poorer outcomes independent of AHI. However, AHI did not emerge as a significant predictor of the overall cognitive functioning domain (p = 0.377). Additionally, although AHI was a significant predictor of the general behavioral functioning domain (p = 0.008), the significance pattern and nature of its relationship with individual behavioral measures were inconsistent in post-hoc analyses.ConclusionThe findings of this study suggest that general behavioral and cognitive function may decline with greater snoring severity. Further, snoring should not simply be assumed to represent a lower severity level of SDB, but should be examined as a potential predictor of relevant outcomes.     

Relationship between obstructive sleep apnoea syndrome and sleep bruxism: a systematic review

Obstructive sleep apnoea syndrome (OSAS) is a clinical risk factor for sleep bruxism (SB). Both OSAS and SB are reported to be associated with sleep‐related arousal reactions, although no clear causative link has been established. An electronic literature search was conducted of the MEDLINE, ScienceDirect, Wiley Online Library, SAGE Journals and EBSCOhost databases covering the period January 2006 and September 2016. Sequential screenings at the title, abstract and full‐text levels were performed. The review included observational studies in the English language with a clearly established aim to assess the relationship between OSAS and SB using full‐night PSG. The seven‐item quality‐assessment tool for experimental bruxism studies was used to assess the methodology across the studies. After a comprehensive screening of titles, abstracts and full texts, only three studies that met the pre‐defined criteria were finally included in this systematic review. Two studies gave evidence that OSAS is associated with the occurrence of SB events: (i) SB events frequently occur during micro‐arousal events consequent on apnoea–hypopnoea (AH) events and (ii) most SB events occur in temporal conjunction with AH events termination. However, one study did not report a strong association between AH and SB events. It can be concluded that there are not enough scientific data to define a clear causative link between OSAS and SB. However, they appear to share common clinical features. Further studies should focus on the intermediate mechanisms between respiratory and SB events.     

Facial phenotype in obstructive sleep apnea–hypopnea syndrome: a systematic review and meta‐analysis

This systematic review and meta‐analysis explores the association between facial phenotype and obstructive sleep apnea–hypopnea syndrome in adults. A comprehensive electronic (Medline via Ovid, Scopus, and Embase) database and reference search were undertaken in relation to imaging modalities for surface craniofacial assessments in subjects with sleep apnea. The outcome measures were surface facial dimensions, morphology and profile. The quality of studies was assessed and a meta‐analysis conducted. The studies were weighted using the inverse variance method, and the random effects model was used to analyse data. This systematic review identified eight case–control studies. In five studies (906 participants), adults with sleep apnea showed increased weighted mean differences in neck circumference by 1.26 mm (P = 0.0001) with extensive heterogeneity between studies (I² = 93%). Only two studies (467 participants) shared the following outcomes: mandible length, lower facial height, mandible width and anterior mandible height parameters. The pooled results demonstrated obstructive sleep apnea syndrome was associated with larger parameters than controls. In conclusion, the surface facial assessment was able to demonstrate some characteristic morphological features, facilitating a meta‐analysis, in adults with obstructive sleep apnea–hypopnea syndrome. The strength of these findings, however, was limited by the heterogeneity of the studies precluding the identification of a clear phenotype.