Y.K. Wing

A controlled study of sleep related disordered breathing in obese children

Background: Unlike the adult sleep related disordered breathing (SDB) patients who are typically obese, the relation between obesity and childhood SDB is not clear. Aims: To investigate whether obese children are more at risk of obstructive SDB when compared to normal population, and whether this risk is potentiated by the presence of pharyngeal lymphoid tissue. Methods: Forty six obese children (age 10.8 (SD 2.3) years; BMI 27.4 (SD 5.1)), and 44 sex and age matched normal weight children (age 11.7 (SD 2.1) years; BMI 18 (SD 1.8)) were studied. All children underwent a set of physical examinations (including the upper airways) and sleep studies. Results: The obese children were different from the normal weight children in terms of type (predominantly obstructive), frequency, and severity of respiratory disturbances. Depending on the criteria used, 26% or 32.6% of obese children had SDB; 2.3% of normal controls had OAI ⩾1 and 4.5% had RDI ⩾5. Presence of SDB was related to presence of tonsils (size >2; range 0–4) (OR 12.67, 95% CI 2.14 to 75.17) and BMI (OR 1.20, 95% CI 1.08 to 1.33). Conclusions: Results suggest that obese children are at increased risk of obstructive SDB; the presence of any pharyngeal lymphoid tissue enlargement in obese children should therefore be aggressively managed.

Ambulatory blood pressure in children with obstructive sleep apnoea: a community based study

Background: Childhood obstructive sleep apnoea (OSA) is increasingly being recognised. Its effects on blood pressure (BP) elevation and hypertension are still controversial. Objective: To evaluate the association between OSA and ambulatory BP in children. Methods: Children aged 6–13 years from randomly selected schools were invited to undergo overnight sleep study and ambulatory BP monitoring after completing a validated OSA questionnaire. OSA was diagnosed if the obstructive apnoea–hypopnoea index (AHI) was >1, and normal controls had AHI <1 and snoring <3 nights per week. Children with OSA were subdivided into a mild group (AHI 1–5) and moderate to severe group (AHI >5). Results: 306 subjects had valid sleep and daytime BP data. Children with OSA had significantly higher BP than normal healthy children during both sleep and wakefulness. BP levels increased with the severity of OSA, and children with moderate to severe disease (AHI >5) were at significantly higher risk for nocturnal systolic (OR 3.9 (95% CI 1.4 to 10.5)) and diastolic (OR 3.3 (95% CI 1.4 to 8.1)) hypertension. Multiple linear regression revealed a significant association between oxygen desaturation index and AHI with daytime and nocturnal BP, respectively, independent of obesity. Conclusions: OSA was associated with elevated daytime and nocturnal BP, and is an independent predictor of nocturnal hypertension. This has important clinical implications as childhood elevated BP predicts future cardiovascular risks. Future studies should examine the effect of therapy for OSA on changes in BP.

Rapid eye movement sleep behavior disorder: Devising controlled active treatment studies for symptomatic and neuroprotective therapy-a consensus statement from the International Rapid Eye Movement Sleep Behavior Disorder Study Group

OBJECTIVES We aimed to provide a consensus statement by the International Rapid Eye Movement Sleep Behavior Disorder Study Group (IRBD-SG) on devising controlled active treatment studies in rapid eye movement sleep behavior disorder (RBD) and devising studies of neuroprotection against Parkinson disease (PD) and related neurodegeneration in RBD. METHODS The consensus statement was generated during the fourth IRBD-SG symposium in Marburg, Germany in 2011. The IRBD-SG identified essential methodologic components for a randomized trial in RBD, including potential screening and diagnostic criteria, inclusion and exclusion criteria, primary and secondary outcomes for symptomatic therapy trials (particularly for melatonin and clonazepam), and potential primary and secondary outcomes for eventual trials with disease-modifying and neuroprotective agents. The latter trials are considered urgent, given the high conversion rate from idiopathic RBD (iRBD) to Parkinsonian disorders (i.e., PD, dementia with Lewy bodies [DLB], multiple system atrophy [MSA]). RESULTS Six inclusion criteria were identified for symptomatic therapy and neuroprotective trials: (1) diagnosis of RBD needs to satisfy the International Classification of Sleep Disorders, second edition, (ICSD-2) criteria; (2) minimum frequency of RBD episodes should preferably be ⩾2 times weekly to allow for assessment of change; (3) if the PD-RBD target population is included, it should be in the early stages of PD defined as Hoehn and Yahr stages 1-3 in Off (untreated); (4) iRBD patients with soft neurologic dysfunction and with operational criteria established by the consensus of study investigators; (5) patients with mild cognitive impairment (MCI); and (6) optimally treated comorbid OSA. Twenty-four exclusion criteria were identified. The primary outcome measure for RBD treatment trials was determined to be the Clinical Global Impression (CGI) efficacy index, consisting of a four-point scale with a four-point side-effect scale. Assessment of video-polysomnographic (vPSG) changes holds promise but is costly and needs further elaboration. Secondary outcome measures include sleep diaries; sleepiness scales; PD sleep scale 2 (PDSS-2); serial motor examinations; cognitive indices; mood and anxiety indices; assessment of frequency of falls, gait impairment, and apathy; fatigue severity scale; and actigraphy and customized bed alarm systems. Consensus also was established for evaluating the clinical and vPSG aspects of RBD. End points for neuroprotective trials in RBD, taking lessons from research in PD, should be focused on the ultimate goal of determining the performance of disease-modifying agents. To date no compound with convincing evidence of disease-modifying or neuroprotective efficacy has been identified in PD. Nevertheless, iRBD patients are considered ideal candidates for neuroprotective studies. CONCLUSIONS The IRBD-SG provides an important platform for developing multinational collaborative studies on RBD such as on environmental risk factors for iRBD, as recently reported in a peer-reviewed journal article, and on controlled active treatment studies for symptomatic and neuroprotective therapy that emerged during the 2011 consensus conference in Marburg, Germany, as described in our report.

Validation of a new REM sleep behavior disorder questionnaire (RBDQ-HK)☆

OBJECTIVES There are limited screening instruments for diagnosis of REM sleep behavior disorder (RBD) and none for quantifying the severity of disease. We aimed to validate a 13-item self-reported RBD questionnaire (RBDQ-HK) for diagnostic and monitoring purposes. METHODS Based on ICSD-II and our previous clinical and empirical work, the RBDQ-HK questionnaire was designed and administered in patients attending university-affiliated sleep clinic and psychiatric out-patient clinic, and subjects from the general population. ROC curve and exploratory factor analysis were employed to evaluate the scale, which had a score ranging from 0 to 100. RESULTS One hundred and seven RBD patients [mean age 62.6 (15.5) years; male 70.1%] and 107 control subjects [mean age 55.3 (9.0) years, male 57.9%] completed the questionnaire. The diagnoses of all the study subjects were independently ascertained by clinical interview and PSG. RBD patients had a significantly higher total RBDQ-HK score [mean (s.d.): 32.1 (16.1), range 3-71] than the control group [9.5 (10.2), range 0-55] (p<0.005). The RBDQ-HK demonstrated robust psychometric properties with moderate sensitivity (82.2%), specificity (86.9%), positive predictive value (PPV; 86.3%), and negative predictive value (NPV; 83.0%), high internal consistency and test-retest reliability. Exploratory factor analysis revealed two components (dream-related and behavioral factors) that corresponded to the essential clinical features of RBD. The best cut-off for total score (range 0-100) was at 18/19 and the best cut-off for factor 2 (behavioral factors including sleep talking, shouting, limb movements and sleep-related injuries, range 0-70) was at 7/8. CONCLUSIONS The RBDQ-HK has satisfactory validity and reliability as a measure of clinical RBD symptoms and severity. It may serve as an effective tool for diagnosis and evaluation of the disease course to facilitate future clinical and research studies.

Blood Pressure is Elevated in Children with Primary Snoring

OBJECTIVES To compare ambulatory blood pressure (ABP) in nonoverweight, prepubertal children with and without primary snoring (PS), and to investigate whether PS is a part of the dose-response relationship between sleep-disordered breathing (SDB) and BP in children. STUDY DESIGN This was a cross-sectional community-based study involving 190 children age 6 to 13 years. Each participant underwent an overnight sleep study and ABP monitoring after completing a validated sleep symptoms questionnaire. Individual systolic blood pressure (SBP), diastolic blood pressure (DBP), and mean arterial BP were calculated for wake and sleep periods. Subjects were hypertensive if mean SBP or DBP was > 95th percentile (relative to sex and height) of reference. RESULTS A total of 56 nonsnoring controls, 46 children with PS, 62 children with an apnea-hypopnea index (AHI) of 1 to 3, and 26 children with an AHI > 3 were identified. The daytime and nighttime BP increased across the severity spectrum of SDB. The dose-response trends for the proportion of subjects with nighttime systolic and diastolic hypertension also were significant. Nighttime DBP was significantly higher in the children with PS compared with controls after adjusting for age, sex, and body mass index. CONCLUSIONS PS was demonstrated to be an aspect of the dose-response relationship between SDB and BP in children and should not be considered completely benign.

Epidemiology of obstructive sleep apnoea syndrome in Chinese children: a two-phase community study

Objective To determine the prevalence and risk factors of obstructive sleep apnoea syndrome (OSAS) in Chinese children using a two-phase community-based study design. Methods Children from 13 primary schools were randomly recruited. A validated OSAS screening questionnaire was completed by their parents. Children at high risk of OSAS and a randomly chosen low-risk group were invited to undergo overnight polysomnographic study and clinical examination. The the sex-specific prevalence rate was measured using different cutoffs (obstructive apnoea hypopnoea index ≥1, ≥1.5, ≥3 and ≥5 and obstructive apnoea index ≥5) and risk factors associated with OSAS were evaluated with logistic regression. Results 6447 completed questionnaires were returned (out of 9172 questionnaires; 70.3%). 586 children (9.1%; 405 boys and 181 girls) children belonged to the high-risk group. A total of 619 (410 and 209 from the high and low-risk group, respectively) subjects underwent overnight polysomnagraphy. Depending on the cutoffs, the prevalence rate of childhood OSAS varied from 4.8% to 40.3%. Using the International Criteria of Sleep Disorders version II, the OSAS prevalence for boys and girls was 5.8% and 3.8%, respectively. Male gender, body mass index z-score and increased adenoid and tonsil size were independently associated with OSAS. Conclusions The prevalence rate of OSAS in children was contingent on the cutoff used. The inclusion of symptoms as a part of the diagnostic criteria greatly reduced the prevalence. A further prospective and outcome study is needed to define a clinically significant diagnostic cutoff for childhood OSAS.

Nocturnal sleep disturbances as a predictor of suicide attempts among psychiatric outpatients: a clinical, epidemiologic, prospective study

OBJECTIVE Nocturnal sleep disturbances, including insomnia and recurrent nightmares, represent common distressing sleep complaints that might have important prognostic and therapeutic implications in psychiatric patients. The present study aimed at investigating nocturnal sleep disturbances in relation to the risk of suicide attempts in a consecutive cohort of psychiatric outpatients. METHOD Participants attending a psychiatric outpatient clinic in Hong Kong were recruited into the study with a detailed sleep questionnaire assessment. The questionnaire was distributed between May and June 2006. Relevant clinical information, with a comprehensive clinical history of patients since their attendance at psychiatric services and 1 year after completion of their questionnaires, was reviewed. RESULTS The final study population consisted of 1,231 psychiatric outpatients with a mean age of 42.5 years (SD = 11.3; range, 18-65). Both frequent insomnia and recurrent nightmares were significantly and independently associated with an increased incidence of suicide attempts 1 year after questionnaire assessment (insomnia: OR = 6.96; 95% CI, 1.21-39.97; recurrent nightmares: OR = 8.17; 95% CI, 1.06-63.13) and an increase in lifetime prevalence of suicide attempts (insomnia: OR = 1.55; 95% CI, 1.06-2.25; recurrent nightmares: OR = 2.43; 95% CI, 1.51-3.91). Comorbid insomnia and nightmares had increased odds of lifetime prevalence (OR = 2.43; 95% CI, 1.53-3.85) and 1-year incidence of suicidal risk (OR = 17.08; 95% CI, 2.64-110.40). Antidepressants, particularly selective serotonin reuptake inhibitors (OR = 1.52; 95% CI, 1.02-2.25), serotonin-norepinephrine reuptake inhibitors (OR = 2.10; 95% CI, 1.15-3.83), heterocyclics (OR = 2.78; 95% CI, 1.21-6.42), and non-benzodiazepine hypnotics (OR = 1.54; 95% CI, 1.02-2.33) were independently associated with recurrent nightmares after adjustment for confounding variables. CONCLUSIONS Nocturnal sleep disturbances, particularly frequent insomnia and recurrent nightmares, were independently associated with enhanced suicidal risk among psychiatric patients. Future studies are warranted to investigate the underlying pathophysiologic mechanism and interventional responses.

Prevalence and risk factors of habitual snoring in primary school children.

OBJECTIVE Our study aimed to determine the prevalence of habitual snoring (HS) in primary school children and to evaluate the diurnal symptoms and conditions that may be associated with it. METHODS A validated questionnaire completed by parents was used to assess the sleep and daytime behaviors of Chinese children aged 5 to 14 years. Thirteen primary schools in two representative districts were randomly selected. RESULTS A total of 6,349 out of 9,172 questionnaires (response rate 69.2%) with complete answers were returned. The prevalence rate of HS was 7.2%. Male sex (odds ratio [OR] [95% CI]: 2.5 [1.7-3.6]), BMI z score (OR [95% CI]: 1.4 [1.1-1.6]), maternal HS (OR [95% CI]: 3.4 [2.0-5.7]), paternal HS (OR [95% CI]: 3.8 [2.7-5.5]), allergic rhinitis (OR [95% CI]: 2.9 [2.0-4.2]), asthma (OR [95% CI]: 2.4 [1.2-5.2]), nasosinusitis (OR [95% CI]: 4.0 [1.5-10.6]), and tonsillitis (OR [95% CI]: 3.1 [1.9-5.1]) in the past 12 months were identified to be independent risk factors associated with HS. HS was also associated with daytime, nocturnal, parasomniac, and sleep-related breathing symptoms. HS was demonstrated to be an independent risk factor for parent-reported poor temper (OR [95% CI]: 1.9 [1.4-2.5]), hyperactivity (OR [95%CI]: 1.7 [1.2-2.5]), and poor school performance (OR [95% CI]: 1.7 [1.2-2.5]). CONCLUSIONS HS was a significant and prevalent problem in primary school children. Male sex, obesity, parental HS, atopic symptoms, and history of upper respiratory infections were significant risk factors. HS was also associated with sleep-disordered breathing symptoms and adverse neurobehavioral outcomes.

A community-based study of insomnia in Hong Kong Chinese children: Prevalence, risk factors and familial aggregation

OBJECTIVES There has been limited data on familial aggregation of insomnia. We aimed to explore the prevalence, risk factors and familial aggregation of childhood insomnia with a large community-based sample. METHODS A community-based epidemiologic study of sleep disorders was conducted among primary school children. Those children with at least one reported biological parent were recruited. A total of 5695 children (mean age 9.2; SD 1.8), 4939 of their reported biological mothers (mean age 38.9; SD 4.6) and 4289 of their reported biological fathers (mean age 43.3; SD 5.5) were studied. RESULTS The rates of insomnia 3 times/week in the past 12 months were 4.0%, 12.8% and 9.7% for children, mothers and fathers, respectively. A robust familial aggregation of insomnia was found even after adjustment of the shared environmental and socio-demographic factors. There was a significant dose-response relationship among the children across their parental status from neither, fathers, mothers to both parents with insomnia [3.0%, 7.1%, 9.5% and 11.9%; with ORs (95% CIs)=2.48 (1.82-4.37) for fathers, 3.42 (2.55-4.59) for mothers and 4.42 (2.42-8.10) for both parents, respectively]. In addition, the frequency of insomniac symptoms of the parents also had a dose-response effect on the rate of insomnia of their children. CONCLUSIONS Insomnia is a common problem in both children and their parents. A significant familial aggregation of childhood onset insomnia was seen in this study even after adjustment of the co-risk factors. There was a dose-response effect of parental insomnia on the rate of insomnia of their children with a slight predilection of maternal influences.

Long-term outcomes and predictors of chronic insomnia: A prospective study in Hong Kong Chinese adults

OBJECTIVES We aimed to determine the longitudinal course and outcome of chronic insomnia in a five-year prospective study in Hong Kong Chinese adults. METHODS Two thousand three hundred and sixteen middle-aged adults (53.3% females, 46.3 ± 5.1 years old at follow-up) were recruited at baseline and follow-up. Participants were divided into three groups: non-insomnia, insomnia symptoms, and insomnia syndrome (insomnia symptoms plus daytime symptoms). Upper airway inflammatory diseases, mental problems, and medical problems were additionally assessed at follow up. RESULTS The incidence of insomnia (symptoms and syndrome) was 5.9%. The persistence rate of insomnia syndrome was 42.7% for insomnia syndrome and 28.2% for insomnia symptoms. New incidence of insomnia was associated with younger age, unemployment, and daytime symptoms, while persistence of insomnia was associated with female sex, lower education level, and daytime symptoms at the baseline (p<0.05). Baseline insomnia syndrome was significantly associated with upper airway inflammatory diseases (including asthma and laryngopharyngitis; adjusted OR=1.97-17.9), mental problems, and medical conditions (including arthritis, psychiatric disorders, chronic pain, and gastroesophageal reflux disease; AOR=2.29-3.77), whereas baseline insomnia symptoms were associated with poor mental health (AOR=2.43), psychiatric disorders (AOR=2.39), and chronic pain (AOR=2.95). CONCLUSIONS Chronic insomnia is a common problem with considerable persistence and incidence rates among middle-aged Chinese adults. Insomnia syndrome has a higher persistence rate with more mental and medical comorbidities when compared with insomnia symptoms without daytime consequences.