Statistics from Altmetric.com
Editor,—We agree that sleep disorders in children are an underrecognised problem and that at least one third of the children with severe problems may have coexisting physical or behavioural problems. However, it is surprising that Rona et al 1 make no mention of obstructive sleep apnoea syndrome (OSAS) as a significant cause of disrupted sleep and daytime morbidity in the children. “Sleeps poorly but lies quietly when awake” might be considered typical of OSAS, and the lack of improvement with age seen in this group may be in part result from the persistence of OSAS (although it is true that many cases may spontaneously improve owing to the regression of adenotonsillar hypertrophy from age 5 years onward). Snoring, a hallmark symptom of OSAS, is a very common symptom in children2 and was not included in Rona et al’s questionnaire, but is easily recognised by most parents and may therefore have excluded many children with OSAS from the behavioural problems group. Parental perception of expiratory wheeze is not accurate (authors’ experience) and is easily confused with inspiratory stridor and stertor, potentially exaggerating the impact of asthma in this group. In addition, nocturnal enuresis is a common association with OSAS3 and one that may be highly responsive to curative measures directed at OSAS.
OSAS is underrecognised in children (variously reported incidence approximately 0.7%) and, in addition to its disruptive effects on steep pattern, it has a profound effect on daytime performance and may lead to irreversible pulmonary hypertension. It is readily diagnosed by polysomnography, and when not associated with craniofacial malformation or neuromuscular disease it can almost be totally cured by adenotonsillectomy.4 Greater awareness of this condition is needed.
Dr Rona et al comment:
We believe that Davies and colleagues may have misunderstood our study—we did not ask parents whether their child’s sleep disturbance was caused by wheezing. The explanatory variables used in our analysis were asked in the same questionnaire, but as separate items. Indeed, the questions on respiratory illness came before the item on disturbed sleep in our questionnaire. The cross sectional design prevented us from establishing a causal link, but the strength of the association and the increased risk of disturbed sleep with increasing frequency of wheezy symptoms is highly suggestive.
Rees and colleagues have highlighted an issue that we did not have in mind when the study was designed. In a recent review Greene and Carroll, although supporting the seriousness of the diagnosis of severe obstructive sleep disordered breathing, are uncertain about the clinical consequences and the management of less serious cases.1-1 We suggest that the condition deserves research based on rather more than the personal experience, clinical series, and non-randomised studies implied in their letter.