The effect of sleep duration and sleep quality on hypertension in middle-aged and older Chinese: the Dongfeng-Tongji Cohort Study

ObjectiveTo examine the independent and combined associations of sleep duration and sleep quality with hypertension in a middle-aged and older Chinese population.MethodsWe included 21,912 individuals aged 62.2 years at baseline from September 2008 to June 2010, and they were followed until October 2013. Sleep duration was self-reported and sleep quality was evaluated with questions designed according to the Pittsburgh Sleep Quality Index. Hypertension was defined as blood pressure ≥140/90 mmHg, or self-reported physician diagnosis of hypertension, or self-reported current use of antihypertensive medication.ResultsIn the cross-sectional analyses, the odds ratio of hypertension prevalence was significantly elevated (OR = 1.13, 95% CI = 1.03–1.24) in those who slept less than 7 h after adjusting for sex, age, body mass index, midday napping, cigarette smoking and sleep quality. It was particularly evident among males (OR = 1.19, 95% CI = 1.01–1.40) and individuals who were thin (OR = 2.00, 95% CI = 1.01–3.93) with full adjustment. The association was also found for sleep duration of 9∼<10 h after adjusting various covariates (OR = 1.14, 95% CI = 1.04–1.27). In addition, impaired sleep quality was only associated with hypertension in obese individuals (OR = 1.25, 95% CI = 1.02–1.50), not in other subgroups. However, no significant association was detected in any category of sleep duration or sleep quality in all models in the prospective analyses, and the results remained unchanged in the subgroup analyses of sex, age and body mass index.ConclusionsThe results of this study provide limited support for association of sleep duration and sleep quality with hypertension in middle-aged and older Chinese. Further studies are needed to confirm the results.     

Intraindividual sleep variability and its association with insomnia identity and poor sleep

ObjectiveInsomnia identity refers to the conviction that one has insomnia, which can occur independently of poor sleep. Night-to-night variability in sleep (termed intraindividual variability [IIV]) may contribute to insomnia identity yet remain undetected via conventional mean analyses. This study compared sleep IIV across four subgroups: noncomplaining good sleepers (NG), complaining poor sleepers (CP), complaining good sleepers (CG), and noncomplaining poor sleepers (NP).MethodsThis study analyzed 14 days of sleep diary data from 723 adults. Participants were classified according to presence/absence of a sleep complaint and presence/absence of poor sleep. A 2 × 2 multivariate analysis of covariance (MANCOVA) was performed to explore differences on five measures of sleep IIV: intraindividual standard deviation in total sleep time (iSD TST), sleep onset latency (iSD SOL), wake after sleep onset (iSD WASO), number of nightly awakenings (iSD NWAK), and sleep efficiency (iSD SE).ResultsMANCOVA revealed significant main effects of poor sleep, sleep complaint, and their interaction on sleep IIV. Poor sleepers exhibited greater IIV across all sleep parameters compared to good sleepers. Similarly, individuals with a sleep complaint exhibited greater IIV compared to individuals with no complaint. The interaction revealed that iSD SOL was significantly greater among CP than NP, and iSD NWAK was significantly greater among CG than NG.ConclusionsGreater night-to-night variability in specific sleep parameters was present among complaining versus noncomplaining sleepers in good and poor sleep subgroups. These findings suggest certain aspects of sleep consistency may be salient for treatment-seeking individuals based on their quantitative sleep status.     

The role of sleep and the hypothalamic-pituitary-adrenal axis for behavioral and emotional problems in very preterm children during middle childhood

Very preterm children are at higher risk to develop behavioral and emotional problems, poor sleep, and altered hypothalamic-pituitary-adrenocortical activity (HPAA). However, knowledge on objective sleep and HPAA as well as their role for the development of behavioral and emotional problems in very preterm children is limited. Fifty-eight very preterm children (<32nd gestational week) and 55 full-term children aged 6–10 years underwent one night of in-home polysomnographic sleep assessment. HPAA was assessed with four saliva samples in the morning (morning cortisol secretion) and four saliva samples in the evening (evening cortisol secretion). Parents completed the Strengths and Difficulties Questionnaire (SDQ) to assess children's behavioral and emotional problems and a subscale of the Children's Sleep Habits Questionnaire to assess sleep disordered breathing. Very preterm children showed more behavioral and emotional problems (SDQ total behavioral/emotional difficulties, emotional symptoms), poorer sleep (more nocturnal awakenings, more stage 2 sleep, less slow wave sleep), and faster decreasing evening cortisol secretion compared to full-term children. Across the whole sample, more stage 2 sleep and/or less slow wave sleep were associated with more SDQ total behavioral/emotional difficulties, hyperactivity-inattention, and peer problems. Lower morning cortisol secretion and lower evening cortisol secretion were associated with more conduct problems. In very preterm children, increased SDQ total behavioral/emotional difficulties was partially explained by less restorative sleep including more stage 2 sleep and less slow wave sleep. This result points to the importance of restorative sleep for the behavioral and emotional development of very preterm children during middle childhood.     

Association between severity of untreated sleep apnoea and postoperative complications following major cardiac surgery: a prospective observational cohort study

ObjectiveTo examine whether untreated sleep apnoea is associated with prolonged Intensive Care Unit (ICU) stay and increased frequency of postoperative ICU complications, in patients undergoing major cardiac surgery.Patients/methodsAdult patients, undergoing elective coronary artery bypass grafting with or without cardiac valve surgery, between March 2013 and July 2014, were considered. We excluded patients participating in other interventional studies, those who had a tracheostomy before surgery, required emergency surgery or were due to be admitted on the day of surgery. Patients underwent inpatient overnight oximetry on the night prior to their surgery to assess for the presence of sleep apnoea. Since oximetry alone cannot differentiate obstructive from central apnoea, the results are reported as sleep apnoea which was diagnosed in patients with an arterial oxygen desaturation index (ODI) ≥ 5/h.ResultsThe primary outcome measure was length of stay (LoS) in ICU in days. The secondary outcome was a composite measure of postoperative complications in ICU. Multivariate models were developed to assess associations between ODI and the primary and secondary outcome measures, adjusting for preselected predictor variables, relative to primary and secondary outcomes. There was no significant association between ODI and ICU LoS, HR 1.0, 95% CI 0.99–1.02; p = 0.12. However we did find a significant association between ODI and postoperative complications in the ICU, OR = 1.1; 95% CI 1.02–1.17; p = 0.014. The probability of developing complications rose with higher ODI, reflecting sleep apnoea severity.ConclusionsAcknowledging the limitations of this prospective study, untreated sleep apnoea did not predict an increased length of stay in ICU but we do report an association with postoperative complications in patients undergoing major cardiac surgery.     

Prevalence and characteristics of positional sleep apnea in the HypnoLaus population-based cohort

Objective/BackgroundTo determine the prevalence of positional obstructive sleep apnea (POSA) and exclusive POSA (ePOSA) in the general population and to assess the factors independently associated with POSA and ePOSA according to gender and menopausal status.Patients/MethodsParticipants of the population-based HypnoLaus Sleep Cohort underwent full polysomnography at home. POSA was defined as an apnea-hypopnea index (AHI) ≥5/h, and supine/non-supine AHI ratio (sAHI/nsAHI) ≥2 (ePOSA when non-supine AHI was normalized).ResultsIn this study, 1719 subjects (40-85y.o. 46% men) with at least 30 min spent in both the supine and non-supine positions were included. OSA was present in 1224 subjects (71%) (AHI >5/H). POSA was present in 53% of all subjects, and in 75% of OSA subjects. ePOSA was present in 26% of all subjects and in 36% of OSA subjects. In multivariate analyses, lower AHI and lower BMI were both associated with POSA and ePOSA in males. In premenopausal females, no single factor was associated with POSA while a lower AHI and an Epworth sleepiness scale >10 were associated with ePOSA. In postmenopausal women, a lower BMI was associated with POSA and a lower AHI and a lower Mallampati score with ePOSA.ConclusionsIn this large population-based study, we found that POSA is present in 53% of the middle-to-older age general population, and in 75% of OSA subjects. ePOSA was present in 36% of OSA subjects, suggesting that a large proportion of them could be treated with positional therapy. AHI and BMI were differently associated with POSA in men, and pre or post-menopausal women.     

Spontaneous improvement in both obstructive sleep apnea and cognitive impairment after stroke

BackgroundKnowledge available about the relationship between obstructive sleep apnea (OSA) and cognitive impairment after stroke is limited. The evolution of OSA and cognitive performance after stroke is not sufficiently described.MethodsWe prospectively enrolled and examined acute stroke patients without previously diagnosed OSA. The following information was collected: (1) demographics, (2) sleep cardio-respiratory polygraphy (PG) at 72 h, day seven, month three, and month 12 after stroke, (3) post-stroke functional disability tests at entry and at months three and 12, and (4) cognition (attention and orientation, memory, verbal fluency, language, and visual-spatial abilities) using the revised Addenbrooke's Cognitive Examination (ACE-R) at months three and 12.ResultsOf 68 patients completing the study, OSA was diagnosed in 42 (61.8%) patients. The mean apnea/hypopnea index (AHI) at study entry of 21.0 ± 13.7 spontaneously declined to 11.6 ± 11.2 at month 12 in the OSA group (p < 0.0005). The total ACE-R score was significantly reduced at months three (p = 0.005) and 12 (p = 0.004) in the OSA group. Poorer performance on the subtests of memory at months 3 (p = 0.039) and 12 (p = 0.040) and verbal fluency at months 3 (p < 0.005) and 12 (p < 0.005) were observed in the OSA group compared to non-OSA group. Visual-spatial abilities in both the OSA (p = 0.001) and non-OSA (p = 0.046) groups and the total ACE-R score in the OSA (p = 0.005) and non-OSA (p = 0.002) groups improved.ConclusionsA high prevalence of OSA and cognitive decline were present in patients after an acute stroke. Spontaneous improvements in both OSA and cognitive impairment were observed.     

Association between sleep duration and the prevalence of hypertension in an elderly rural population of China

BackgroundPrevious studies have examined an association between sleep duration and hypertension, but the conclusions remain inconsistent.MethodsWe conducted a cross-sectional study in a community-based rural elderly population of Beijing, China. A total of 2397 participants (967 male and 1430 female) completed the survey. Sleep duration was assessed in a face-to-face interview and was self-reported. Hypertension was defined as systolic blood pressure (BP) ≥ 140 mm Hg and/or diastolic BP ≥ 90 mm Hg and/or receiving treatment for hypertension. Multiple logistic regression was used to estimate the association between gender-specific sleep duration and hypertension prevalence.ResultsOverall, no significant differences were observed among female participants and the total participants, and the differences were statistically significant only in men. After adjusting for potential confounding variables, the odds ratio (OR) and 95% confidential interval (CI) of having hypertension was 1.33 (1.00, 1.77) in men who slept for ≥9 h compared with those slept for six to eight hours per 24-h period. Furthermore, a one hour nap was associated with less likelihood of hypertension in men compared with those who did not nap, with an adjusted OR (95% CI) of 0.61 (0.41, 0.90).ConclusionIn a community-based rural elderly population of China, we found that sleep duration of six to eight hours per 24-h period and a one hour nap were significantly associated with lower risk of hypertension only among male participants after adjustment for potential confounders. Further studies are still needed to determine the relationships between 24-h, nighttime, and daytime sleep duration separately with hypertension, and to explore the biological mechanisms underlying the gender-related association.     

Awareness and knowledge of obstructive sleep apnea among the general population

BackgroundObstructive sleep apnea (OSA) is an increasingly prevalent condition that remains largely undiagnosed. We aimed to assess the level of awareness and knowledge of OSA among the general population.MethodsThe Singapore Health 2 was a population-based study that comprised interview and health screening components. Out of 2720 subjects who completed the interview component, 2080 subjects gave consent for further health surveys. We contacted these subjects and conducted a structured telephone interview.ResultsWe completed 1306 telephone interviews (response rate 62.8%). Two hundred and eighty-one (21.5%) respondents were aware of OSA, but only 170 (13.0%) respondents could define OSA correctly. A total of 77 (5.9%), 158 (12.1%), 150 (11.5%) and 110 (8.4%) respondents were able to correctly list at least one risk factor, symptom, health consequence and treatment options for OSA, respectively. The most common sources of information about OSA were traditional media such as newspapers (42.0%), internet (14.2%) or relatives and friends (14.6%). On multivariate analysis, respondents were more likely to define OSA correctly if they were older (≥61years), (odds ratio of 2.99, 95% Confidence Interval [CI]: 1.66–5.41), were Chinese as compared to Indians (odds ratio 2.63, 95% CI: 1.46–4.72), had higher levels of income (odds ratio 2.18, 95% CI 1.16–4.10) and post-secondary education (odds ratio 2.87, 95% CI: 1.28–6.45).ConclusionAwareness and knowledge of OSA among the general population is currently poor. The effectiveness of ongoing health education campaigns to increase awareness should be monitored by examining temporal trends in public knowledge of sleep apnea.     

Back to sleep or not: the effect of the supine position on pediatric OSA: Sleeping position in children with OSA

BackgroundIn both adults and children, obstructive sleep apnea (OSA) has significant adverse cardiovascular consequences. In adults, sleeping position has a marked effect on the severity of OSA; however, the limited number of studies conducted in children have reported conflicting findings. We aimed to evaluate the effect of sleeping position on OSA severity and the cardiovascular consequences in preschool-aged children.MethodsThis was a retrospective analysis of children (3–5 years of age) diagnosed with OSA (n = 75) and nonsnoring controls (n = 25). Sleeping position was classified as supine, semi-supine, left lateral, right lateral, prone, and semi-prone by using video recordings during one night of attended polysomnography. OSA severity and cardiovascular parameters were compared between the positions.ResultsAll children spent significantly more sleep time in the supine position than in any other position. The obstructive apnea-hypopnea index was higher in the supine position than in the other sleeping positions during NREM (p < 0.05), higher in the moderate/severe OSA group when sleeping in the supine position than when sleeping in the left and right lateral positions (p < 0.05 for both) and prone position (p = 0.007) during REM. Sympathovagal balance was decreased in children with OSA in the supine and lateral positions (p < 0.05).ConclusionsThis study identified that preschool-aged children, whether nonsnoring controls or children with OSA, predominately sleep in the supine position, and OSA was more severe in the supine position. We suggest that to avoid the supine sleep position, positional therapy has the potential to ameliorate OSA severity, and the known cardiovascular consequences.     

Prevalence and risk factors of type 2 diabetes in insomnia sufferers: a study on 1311 individuals referred for sleep examinations

BackgroundSeveral studies have investigated the particular relationship between insomnia and type 2 diabetes. However, few studies have investigated the prevalence and risk factors for type 2 diabetes in insomnia sufferers. The aim of this study was to examine the prevalence and risk factors of type 2 diabetes in a large sample of insomnia sufferers.MethodsData from 1311 insomnia sufferers recruited from the research database of the Erasme Hospital sleep laboratory were analyzed. Only individuals with a diagnosis of type 2 diabetes according to the diagnostic criteria of the American Diabetes Association at admission were included in the diabetes group. Logistic regression analyses were conducted to examine clinical and demographic risk factors of type 2 diabetes in insomnia sufferers.ResultsThe prevalence of type 2 diabetes in insomnia sufferers is 21.13%. Multivariate logistic regression analysis revealed that significant risk factors of type 2 diabetes in insomnia sufferers were as follows: being male, Z-drugs use, high blood pressure, hypertriglyceridemia, alcohol consumption of ≥4 units/day, BMI ≥25 & <30 kg/m², BMI ≥30 kg/m², age ≥50 years, C-reactive protein ≥4.5 mg/L, a sleep duration of <6.5 h, apnea-hypopnea index ≥15/hour, periodic limb movements index ≥26/hour, and severe complaints of early morning awakening.ConclusionType 2 diabetes is a common pathology in insomnia sufferers. In this subpopulation, most of the risk factors for type 2 diabetes are reversible, which justifies better prevention and management of this pathology in order to avoid its negative consequences.     

Comparisons of measures used to screen for obstructive sleep apnea in patients referred to a sleep clinic

Study objectivesObstructive Sleep Apnea (OSA) contributes to all-cause mortality. An American Academy of Sleep Medicine task force is focusing on improving detection and categorization of OSA symptoms and severity to promote screening, assessment, and diagnosis. The purpose of this study was to psychometrically compare measures used in OSA screening (Berlin, Epworth Sleepiness Scale (ESS), STOP Bang) and a portable sleep monitor (PSM) to apnea-hypopnea index (AHI) and levels from polysomnogram (PSG).MethodsAn observational, cross-sectional design was used. Patients referred to a sleep specialist were enrolled at initial sleep evaluation. Participants completed measures used in OSA screening, then sent home for one night using PSM. PSGs were ordered by the physician and AHI results were obtained from the medical record.ResultsParticipants (N = 170) were enrolled in the study. Almost all participants completed the OSA measures, approximately half-completed PSM measurement, and the majority completed laboratory PSG. The STOP Bang had the highest levels of sensitivity; the ESS had the lowest. The ESS had the highest specificity and reliability levels; the STOP Bang had the lowest. The PSM measure had the highest positive predictive value (PPV) and the strongest psychometric properties of the screening measures.ConclusionsThe STOP Bang was the preferred self-report OSA screening measure because of high levels of sensitivity. The ESS was the least desirable measure. PSM measurement consistently predicted the presence of OSA but at the expense of low sensitivity at AHI levels ≥30. This expands the knowledge of validity testing of screening measures used for OSA.     

A novel approach using actigraphy to quantify the level of disruption of sleep by in-home polysomnography: the MrOS Sleep Study: Sleep disruption by polysomnography

BackgroundThe “first-night effect” of polysomnography (PSG) has been previously studied; however, the ability to quantify the sleep disruption level has been confounded with the use of PSG on all nights. We used actigraphy to quantify disruption level and examined characteristics associated with disruption.MethodsTotally, 778 older men (76.2 ± 5.4 years) from a population-based study at six US centers underwent one night of in-home PSG. Actigraphy was performed on the PSG night and three subsequent nights. Actigraphically measured total sleep time (TST), sleep efficiency (SE), wake after sleep onset (WASO), and sleep onset latency (SOL) from the PSG night and subsequent nights were compared. Linear regression models were used to examine the association of characteristics and sleep disruption.ResultsOn average, sleep on the PSG night was worse than the following night (p < 0.05, TST 21 ± 85 min less, SE 2.3 ± 11.3% less, WASO 4.9 ± 51.8 min more, SOL 6.6 ± 56.2 min more). Sleep on the PSG night was significantly worse than that two and three nights later. Characteristics associated with greater sleep disruption on the PSG night included older age, higher apnea–hypopnea index, worse neuromuscular function, and more depressive symptoms. Minorities and men with excessive daytime sleepiness slept somewhat better on the PSG night.ConclusionsAmong older men, there was sleep disruption on the PSG night, which may lead to sleep time underestimation. The increase of sleep on the night after the PSG suggests that data from the second monitoring may overestimate sleep.     

Differences in sleep problems between Japanese and Chinese preschoolers: a cross-cultural comparison within the Asian region

Study objectivesPrevious studies have performed cross-cultural comparisons of differences in childhood sleep problems between Asian and Western countries. However, whether such differences can be observed among Asian countries remains unclear. The present study aimed to investigate differences in the pattern of sleep problems between Japanese and Chinese preschoolers.MethodsData were collected from one city in Japan and 10 cities in China. The present study recruited 438 Japanese and 1020 Chinese preschoolers aged four and five years. Sleep problems and patterns were assessed on the basis of parental reports using the Children's Sleep Habits Questionnaire (CSHQ).ResultsAnalysis of covariance revealed no significant difference in total CSHQ scores between Japanese and Chinese preschoolers, thus indicating that the total severity of sleep problems did not differ between the groups. Japanese preschoolers exhibited higher scores on the bedtime resistance subscale of the CSHQ than Chinese preschoolers. Conversely, Chinese preschoolers exhibited higher subscale scores for night wakings and sleep-disordered breathing. In addition, Japanese preschoolers exhibited earlier bedtimes and wake times and shorter total sleep times than Chinese preschoolers.ConclusionsOur findings indicate that the patterns of sleep problems in preschoolers differ between Japan and China and that such differences may be due to differences in cosleeping practices, bedtime routines, and/or environmental conditions. Thus, investigators studying sleep in preschoolers should consider regional differences in the pattern of sleep problems, even among Asian countries.     

Correspondence of maternal and paternal perception of school-aged children's sleep with in-home sleep-electroencephalography and diary-reports of children's sleep

ObjectiveParents are often the first to report children's sleep difficulties. The aim of the present study was to evaluate the accuracy of parent reports by examining the correspondence of maternal and paternal reports of children's sleep with in-home electroencephalography (EEG) sleep assessment and sleep diary reports.MethodsA total of 143 children (57 formerly very preterm born children) aged 7–12 years underwent one night of in-home sleep-EEG; mothers and fathers reported children's sleep-related behavior by using the German version of the Children's Sleep Habits Questionnaire, and children and parents together completed a sleep diary of children's sleep.ResultsLess EEG-derived total sleep time (TST) was associated with increased mother questionnaire reports of sleep duration problems, while less sleep efficiency (SE) and longer sleep onset latency (SOL) were associated with increased mother questionnaire reports of sleep onset delay. For fathers, only longer SOL was related to increased father questionnaire reports of sleep onset delay. The abovementioned associations did not change with children's increasing age and did not differ for boys and girls. More parent questionnaire reports of sleep duration problems, sleep onset delay, and night wakings were related to shorter diary reports of sleep duration, increased sleep latency, and more nocturnal awakenings, respectively.ConclusionsMother questionnaire reports of children's sleep corresponded moderately with objective measures of TST, SE, and SOL assessed with in-home sleep-EEG. Both mother and father questionnaire reports of children's sleep duration problems, sleep onset delay, and night wakings were related to diary reports of children's sleep.     

Associations between actigraphy-assessed sleep,inflammatory markers,and insulin resistance in the Midlife Development in the United States (MIDUS) study

BackgroundDisturbed sleep has been associated with increased insulin resistance and elevated inflammation. Although there is growing body of evidence that activation of inflammatory pathways plays a crucial role in the development of insulin resistance, the mediational model whereby sleep disturbances influence inflammation that drives insulin resistance has not been fully assessed in general population studies with objectively measured sleep. This study aimed to examine associations between objectively measured sleep, inflammatory markers, and insulin resistance simultaneously and in a mediational analysis, thereby offering insights into the possible causal model.MethodsCross-sectional data collected from 2004 to 2009 during the Midlife Development in the United States II biomarker project were used. The study population included 374 community-based participants (138 men and 236 women) who completed seven nights of wrist actigraphy. Multiple regressions controlling for age and statistically significant variables in univariate regressions were performed to evaluate the associations between actigraphy-assessed sleep measures, inflammatory cytokines, and insulin resistance.ResultsThe regression models showed that in women, higher sleep onset latency (SOL) was associated with higher insulin resistance after controlling for age, smoking, obesity, diabetes, depression, and inflammatory cytokines. Higher SOL was also associated with higher interleukin (IL)-6 and C-reactive protein (CRP) levels in women, but no association was found in men. Using mediation models in women, the association between SOL and insulin resistance was partially explained by the indirect effect of inflammatory cytokines.ConclusionA combination of inflammation and other unidentified pathways may contribute to the relationship between disturbed sleep and glucose homeostasis.     

Impact of adolescent peer aggression on later educational and employment outcomes in an Australian cohort

This study used prospective birth cohort data to analyse the relationship between peer aggression at 14 years of age and educational and employment outcomes at 17 years (N = 1091) and 20 years (N = 1003). Participants from the Western Australian Pregnancy Cohort (Raine) study were divided into mutually exclusive categories of peer aggression. Involvement in peer aggression was reported by 40.2% (10.1% victims; 21.4% perpetrators; 8.7% victim–perpetrators) of participants. Participants involved in any form of peer aggression were less likely to complete secondary school. Perpetrators and victim–perpetrators of peer aggression were more likely to be in the ‘No Education, Employment or Training’ group at 20 years of age. This association was explained by non-completion of secondary school. These findings demonstrate a robust association between involvement in peer aggression and non-completion of secondary school, which in turn was associated with an increased risk of poor educational and employment outcomes in early adulthood.