The impact of sleep disordered breathing on cardiovascular health in overweight children.

BACKGROUND: Up to 50% of overweight/obese children have obstructive sleep apnea (OSA) compared to up to 6% of normal weight children. We compared cardiovascular variables between normal weight and overweight/obese children with and without OSA, and controls. METHODS: Seventy-four referred children and 24 normal weight non-snoring controls (8-18 years) were recruited. Referred children were grouped according to their obstructive apnea hypopnea index (OAHI): OSA (>1 event/h) or primary snoring (PS ≤ 1 event/h) and whether they were normal weight (BMI z-score <1.04) or overweight/obese (BMI z-score ≥ 1.04). Wake blood pressure (BP), heart rate (HR), and pulse transit time (PTT, an inverse continuous surrogate measure of blood pressure) during sleep were recorded. RESULTS: Wake BP was higher in the overweight/obese OSA group than in the control, normal weight PS, and overweight/obese PS groups (p < 0.05 for all). During sleep, BP, and HR were elevated in the overweight/obese OSA group compared to those in non-snoring controls (p < 0.05). More children who were overweight/obese had reduced BP and HR dipping from wake to sleep than normal weight children. The BMI z-score predicted HR and PTT when asleep and both age and BMI z-score predicted BP when awake. CONCLUSION: This study showed that BMI has both combined and independent effects on BP and HR in children with OSA. We have previously shown that treatment of OSA reduces BP and suggest that treatment of OSA in the growing number of overweight/obese children may improve cardiovascular outcomes.

Risk factors for obstructive sleep apnoea in Australian children.

AIM: This study aims to determine whether demographic or clinical factors predict obstructive sleep apnoea (OSA) severity in Australian children. METHODS: Demographic details and medical histories of 301 Australian children (3-17 years old) referred for assessment of OSA were examined retrospectively. Children underwent overnight polysomnography and were classified as having primary snoring (PS) (obstructive apnoea hypopnoea index (OAHI) ≤ 1 event per hour; n = 150), mild OSA (>1 OAHI ≤ 5 events per hour; n = 76) or moderate/severe (MS) OSA (OAHI > 5 events per hour; n = 75). Information obtained from parent-report questionnaire determined the predictive value of the following factors for determining OSA severity: gender, ethnicity, body mass index, asthma and/or allergic rhinitis, socio-economic status and parental smoking status (mother/father/both). Chi-squared analyses were used to compare the distribution of the demographic and clinical factors across the three groups. Statistically significant risk factors were subsequently entered into logistic regression analysis. RESULTS: Ethnicity and parental smoking were significant risk factors for MS OSA. Children with non-Caucasian ethnicity were 36% more likely than Caucasian children to be diagnosed with MS OSA than PS (P = 0.002). Children with fathers who smoked were 53% more likely to have MS OSA than PS compared with those with fathers who did not smoke (P = 0.008). Obesity was associated with OSA severity in primary school-aged children only. Gender, socio-economic status and history of asthma and/or allergic rhinitis were not risk factors. CONCLUSIONS: Non-Caucasian ethnicity, paternal smoking and obesity in older children were associated with an increased risk of polysomnography-confirmed MS OSA in Australian children.

Long-Term Improvements in Sleep and Respiratory Parameters in Preschool Children Following Treatment of Sleep Disordered Breathing.

STUDY OBJECTIVE: Sleep disordered breathing (SDB) in preschool-aged children is common, but long-term outcomes have not been investigated. We aimed to compare sleep and respiratory parameters in preschool children to examine the effects of treatment or non-treatment after 3 years. METHODS: Children (3-5 years) diagnosed with SDB (n = 45) and non-snoring controls (n = 30) returned for repeat overnight polysomnography (39% of original cohort), 3 years following baseline polysomnography. Children with SDB were grouped according to whether they had received treatment or not. SDB resolution was defined as an obstructive apnea hypopnea index (OAHI) ≤ 1 event/h, no snoring detected on polysomnography and habitual snoring not indicated by parents on questionnaire. RESULTS: Fifty-one percent (n = 23) of the children with SDB were treated. Overall, SDB resolved in 49% (n = 22), either spontaneously (n = 8) or with treatment (n = 14). SDB remained unresolved in 39% (n = 9) of those treated and 64% (n = 14) of the children who were untreated. Two of the non-snoring controls developed SDB at follow-up. The treated group had significantly lower OAHI (p < 0.01), respiratory disturbance index (p < 0.001), total arousal and respiratory arousal indices (p < 0.01 for both) at follow-up compared with baseline. There were no differences between studies for the untreated group. CONCLUSIONS: Although treatment resulted in an improvement in indices related to SDB severity, 39% had SDB 3 years following diagnosis. These findings highlight that parents should be made aware of the possibility that SDB may persist or recur several years after treatment. This is relevant regardless of the severity of SDB at baseline and the treatment given.

Long-term effects of caffeine therapy for apnea of prematurity on sleep at school age.

RATIONALE: Apnea of prematurity is a common condition that is usually treated with caffeine, an adenosine receptor blocker that has powerful influences on the central nervous system. However, little is known about the long-term effects of caffeine on sleep in the developing brain. OBJECTIVES: We hypothesized that neonatal caffeine use resulted in long-term abnormalities in sleep architecture and breathing during sleep. METHODS: A total of 201 ex-preterm children aged 5-12 years who participated as neonates in a double-blind, randomized, controlled clinical trial of caffeine versus placebo underwent actigraphy, polysomnography, and parental sleep questionnaires. Coprimary outcomes were total sleep time on actigraphy and apnea-hypopnea index on polysomnography. MEASUREMENTS AND MAIN RESULTS: There were no significant differences in primary outcomes between the caffeine group and the placebo (adjusted mean difference of -6.7 [95% confidence interval (CI) = -15.3 to 2.0 min]; P = 0.13 for actigraphic total sleep time; and adjusted rate ratio [caffeine/placebo] for apnea-hypopnea index of 0.89 [95% CI = 0.55-1.43]; P = 0.63). Polysomnographic total recording time and total sleep time were longer in the caffeine group, but there was no difference in sleep efficiency between groups. The percentage of children with obstructive sleep apnea (8.2% of caffeine group versus 11.0% of placebo; P = 0.22) or elevated periodic limb movements of sleep (17.5% in caffeine group versus 11% in placebo group) was high, but did not differ significantly between groups. CONCLUSIONS: Therapeutic neonatal caffeine administration has no long-term effects on sleep duration or sleep apnea during childhood. Ex-preterm infants, regardless of caffeine status, are at risk for obstructive sleep apnea and periodic limb movements in later childhood.

Long-term changes in neurocognition and behavior following treatment of sleep disordered breathing in school-aged children.

STUDY OBJECTIVES: Sleep disordered breathing (SDB) in children is associated with detrimental neurocognitive and behavioral consequences. The long term impact of treatment on these outcomes is unknown. This study examined the long-term effect of treatment of SDB on neurocognition, academic ability, and behavior in a cohort of school-aged children. DESIGN: Four-year longitudinal study. Children originally diagnosed with SDB and healthy non-snoring controls underwent repeat polysomnography and age-standardized neurocognitive and behavioral assessment 4y following initial testing. SETTING: Melbourne Children's Sleep Centre, Melbourne, Australia. PARTICIPANTS: Children 12-16 years of age, originally assessed at 7-12 years, were categorized into Treated (N = 12), Untreated (N = 26), and Control (N = 18) groups. INTERVENTIONS: Adenotonsillectomy, Tonsillectomy, Nasal Steroids. Decision to treat was independent of this study. MEASUREMENTS AND RESULTS: Changes in sleep and respiratory parameters over time were assessed. A decrease in obstructive apnea hypopnea index (OAHI) from Time 1 to Time 2 was seen in 63% and 100% of the Untreated and Treated groups, respectively. The predictive relationship between change in OAHI and standardized neurocognitive, academic, and behavioral scores over time was examined. Improvements in OAHI were predictive of improvements in Performance IQ, but not Verbal IQ or academic measures. Initial group differences in behavioral assessment on the Child Behavior Checklist did not change over time. Children with SDB at baseline continued to exhibit significantly poorer behavior than Controls at follow-up, irrespective of treatment. CONCLUSIONS: After four years, improvements in SDB are concomitant with improvements in some areas of neurocognition, but not academic ability or behavior in school-aged children.

Pediatric Sleep Survey Instrument--a screening tool for sleep disordered breathing.

PURPOSE: The aim of this study was to assess the construct validity and clinical application of the Pediatric Sleep Survey Instrument (PSSI) as a tool to screen for sleep disordered breathing (SDB) in children. METHODS: Polysomnography (PSG) outcomes and PSSI subscale scores were compared between a clinical cohort (N = 87, 5-10 years, 62 M/25 F) and a nonsnoring community sample (N = 55, 5-10 years, 28 M/27 F). Group comparisons assessed the ability of the PSSI subscales to discriminate between the clinical and community cohorts. Receiver operating characteristic (ROC) curves assessed construct validity, with the Apnea/Hypopnea Index (AHI) >5 events/h, OSA-18 score >60, and Pediatric Daytime Sleepiness Scale (PDSS) above the 70th percentile as the target references. RESULTS: The clinical group had more respiratory events, respiratory-related arousals, fragmented sleep, and lower oxygen saturation nadir than the community group (p < 0.001 for all). PSSI subscale scores of Morning Tiredness, Night Arousals, SDB, and Restless Sleep were higher (p < 0.001 for all) in the clinical cohort, confirming the tool's ability to identify clinically relevant sleep problems. ROC curves confirmed the diagnostic accuracy of the SDB subscale against an AHI > 5 events/h (area under the curve (AUC) = 0.7), an OSA-18 score >60 (AUC = 0.7), and a PDSS score in the 70th percentile (AUC = 0.8). The Morning Tiredness subscale accurately predicted a PDSS score in the 70th percentile (AUC = 0.8). A cutoff score of 5 on the SDB subscale showed a sensitivity of 0.94 and a specificity of 0.76, correctly identifying 77 and 100 % of the clinical and community cohorts, respectively. CONCLUSION: The PSSI Sleep Disordered Breathing subscale is a valid tool for screening SDB and daytime sleepiness in children aged 5-10 years.