WHAT'S KNOWN ON THIS SUBJECT: Obstructive sleep apnea syndrome (OSAS) prevalence in children with sickle cell anemia is not well described. Although these children often experience nocturnal oxygen desaturation, it is unclear whether they are more likely to have OSAS.WHAT THIS STUDY ADDS: Children with sickle cell anemia have a high prevalence of OSAS with typical symptoms, beyond just nocturnal oxyhemoglobin desaturation. This study supports the need for increased efforts to screen for, diagnose, and treat OSAS in this vulnerable population. abstract OBJECTIVE: To ascertain the prevalence of and risk factors for obstructive sleep apnea syndrome (OSAS) in children with sickle cell anemia (SCA). METHODS:Cross-sectional baseline data were analyzed from the Sleep and Asthma Cohort Study, a multicenter prospective study designed to evaluate the contribution of sleep and breathing abnormalities to SCArelated morbidity in children ages 4 to 18 years, unselected for OSAS symptoms or asthma. Multivariable logistic regression assessed the relationships between OSAS status on the basis of overnight inlaboratory polysomnography and putative risk factors obtained from questionnaires and direct measurements. RESULTS:Participants included 243 children with a median age of 10 years; 50% were boys, 99% were of African heritage, and 95% were homozygous for b S hemoglobin. OSAS, defined by obstructive apnea hypopnea indices, was present in 100 (41%) or 25 (10%) children at cutpoints of $1 or $5, respectively. In univariate analyses, OSAS was associated with higher levels of habitual snoring, lower waking pulse oxygen saturation (SpO 2 ), reduced lung function, less caretaker education, and non-preterm birth. Lower sleep-related SpO 2 metrics were also associated with higher obstructive apnea hypopnea indices. In multivariable analyses, habitual snoring and lower waking SpO 2 remained risk factors for OSAS in children with SCA. CONCLUSIONS:The prevalence of OSAS in children with SCA is higher than in the general pediatric population. Habitual snoring and lower waking SpO 2 values, data easily obtained in routine care, were the strongest OSAS risk factors. Because OSAS is a treatable condition with adverse health outcomes, greater efforts are needed to screen, diagnose, and treat OSAS in this high-risk, vulnerable population.

Moderate to severe OSA is common in very young children with DS. Examination of tonsillar size did not predict OSA severity. Population-based screening for OSA is recommended in these children, and domiciliary cardiorespiratory polygraphy is an acceptable screening approach. Further research is required to understand the natural history, associated morbidity, optimal screening methodology and treatment modality for OSA in these children.

Previous research has identified cognitive impairment in children with sickle cell anemia (SCA, Hemoglobin SS) compared with controls, partly accounted for by overt neuropathology after clinical stroke, “covert” (“silent”) infarction, and severity of anemia. However, cognitive deficits have also been identified in children with SCA with no history of stroke and a normal T2-weighted magnetic resonance imaging (MRI) scan. Our aim was to investigate whether nocturnal hemoglobin oxygen desaturation and sleep fragmentation could be associated with cognitive impairment in children with SCA. We assessed 10 children with SCA (9 with normal MRI) using neuropsychological measures of executive function. Cognitive assessment was immediately followed by overnight polysomnography to record nocturnal hemoglobin oxygen saturation and sleep arousals. Decreases in hemoglobin oxygen saturation and/or increased sleep arousals were associated with reduced performance on cognitive assessment. Nocturnal hemoglobin oxygen desaturation and sleep fragmentation may be a contributing factor to executive dysfunction in SCA.

Purpose Enuresis and sleep disordered breathing are common among children with sickle cell anemia. We evaluated whether enuresis is associated with sleep disordered breathing in children with sickle cell anemia. Materials and Methods Baseline data were used from a multicenter prospective cohort study of 221 unselected children with sickle cell anemia. A questionnaire was used to evaluate, by parental report during the previous month, the presence of enuresis and its severity. Overnight polysomnography was used to determine the presence of sleep disordered breathing by the number of obstructive apneas and/or hypopneas per hour of sleep. Logistic and ordinal regression models were used to evaluate the association of sleep disordered breathing and enuresis. Results The mean age of participants was 10.1 years (median 10.0, range 4 to 19). Enuresis occurred in 38.9% of participants and was significantly associated with an obstructive apnea-hypopnea index of 2 or more per hour after adjusting for age and gender (OR 2.19; 95% CI 1.09, 4.40; p = 0.03). Enuresis severity was associated with obstructive apneas and hypopneas with 3% or more desaturation 2 or more times per hour with and without habitual snoring (OR 3.23; 95% CI 1.53, 6.81; p = 0.001 and OR 2.07; 95% CI 1.09, 3.92; p = 0.03, respectively). Conclusions In this unselected group of children with sickle cell anemia, sleep disordered breathing was associated with enuresis. Results of this study support that children with sickle cell anemia who present with enuresis should be evaluated by a pulmonologist for sleep disordered breathing.

A wide range of physiological responses to altitude are evident in healthy children. This study should inform future larger studies in children to improve understanding of responses to hypoxia in health and disease.