Editorial Board
Publication date:
October 2014
Source:Sleep Medicine, Volume 15, Issue 10
Weight loss from lifestyle interventions and severity of sleep apnoea: a systematic review and meta-analysis
Publication date:
October 2014
Source:Sleep Medicine, Volume 15, Issue 10
Author(s): Lana J. Mitchell , Zoe E. Davidson , Maxine Bonham , Denise M. O'Driscoll , Garun S. Hamilton , Helen Truby
Background
Excess body weight is a risk factor for obstructive sleep apnoea (OSA). The aim of the systematic review was to establish whether weight loss via lifestyle interventions such as diet and exercise are useful in the treatment of OSA.
Methods
A literature search was conducted between 1980 and February 2012. Systematic reviews and randomised controlled trials (RCTs) with participants who had OSA, were overweight or obese, and who had undergone lifestyle interventions with the aim of improving sleep apnoea were included. Meta analyses were conducted for a subset of RCTs with appropriate data.
Results
Two systematic reviews and eight RCTs were included. Meta-analyses were conducted for four RCTs comparing intensive lifestyle interventions to a control. The overall weighted mean differences for weight change, change in apnoea -hypopnoea index (AHI) and change in oxygen desaturation index of ≥4% were as follows: −13.76 kg (95% confidence interval (CI) −19.21, −-8.32), −16.09 (95% CI −25.64, −6.54) and −14.18 (95% CI −24.23, −4.13), respectively. Although high heterogeneity within the meta analyses, all studies favoured the interventions. Long-term follow-up data from three RCTs suggest that improvements in weight and AHI are maintained for up to 60 months.
Conclusions
Intensive lifestyle interventions are effective in the treatment of OSA, resulting in significant weight loss and a reduction in sleep apnoea severity. Weight loss via intensive lifestyle interventions could be encouraged as a treatment for mild to moderate OSA.
Two features of sleep slow waves: homeostatic and reactive aspects – from long term to instant sleep homeostasis
Publication date:
October 2014
Source:Sleep Medicine, Volume 15, Issue 10
Author(s): Péter Halász , Róbert Bódizs , Liborio Parrino , Mario Terzano
In this paper we reviewed results of sleep research that have changed the views about sleep slow wave homeostasis, which involve use-dependent and experience-dependent local aspects to understand more of the physiology of plastic changes during sleep. Apart from the traditional homeostatic slow-wave economy, we also overviewed research on the existence and role of reactive aspects of sleep slow waves. Based on the results from spontaneous and artificially evoked slow waves, we offer a new hypothesis on instant slow wave homeostatic regulation. This regulation compensates for any potentially sleep-disturbing events by providing instant “delta injections” to maintain the nightly delta level, thus protecting cognitive functions located in the frontal lobe. We suggest that this double (long-term /instant) homeostasis provides double security for the frontal lobes in order to protect cognitive functions. The incorporation of reactive slow wave activity (SWA) makes sleep regulation more dynamic and provides more room for the internalization of external influences during sleep.
Habitual sleep patterns and the distribution of body mass index: cross-sectional findings among Swedish men and women
Publication date:
October 2014
Source:Sleep Medicine, Volume 15, Issue 10
Author(s): Anna Westerlund , Matteo Bottai , Hans-Olov Adami , Rino Bellocco , Olof Nyrén , Torbjörn Åkerstedt , Ylva Trolle Lagerros
Objective
To compare distributions of body mass index (BMI) between individuals with different habitual sleep patterns.
Methods
We performed cross-sectional analyses of 40,197 Swedish adults (64% women), who reported sleep duration and quality, weight, height, and possible confounding factors in 1997. Using quantile regression, we estimated associations between sleep patterns and selected percentiles of the distribution of BMI.
Results
While the medians were similar, larger adjusted values of BMI were estimated in the upper part of the distribution among men and women with short sleep (≤5 h) compared with medium-length sleep (6–8 h). For example, in men, the 90th percentile of BMI was 0.80 kg/m2 (95% confidence interval: 0.17–1.43 kg/m2) higher among short sleepers. In women, long sleepers (≥9 h) also showed larger values in the upper part of the BMI distribution; the 90th percentile was 1.23 kg/m2 (0.42–2.04 kg/m2) higher than in medium-length sleepers. In male long sleepers, smaller values were estimated in the lower part of the BMI distribution; the 10th percentile was 0.84 kg/m2 lower (0.35–1.32 kg/m2) than in medium-length sleepers. The 90th percentile of BMI in women with poor-quality compared with good-quality sleep was larger by 0.82 kg/m2 (0.47–1.16 kg/m2); the 10th percentile was smaller by 0.17 kg/m2 (0.02–0.32 kg/m2).
Conclusions
Short, long or poor-quality sleepers showed larger, or smaller, values at the tails of the BMI distribution, but similar medians. Hence, unfavorable sleep patterns and BMI were associated only in a subset of this study population.
Both habitual short sleepers and long sleepers are at greater risk of obesity: a population-based 10-year follow-up in women
Publication date:
October 2014
Source:Sleep Medicine, Volume 15, Issue 10
Author(s): Jenny Theorell-Haglöw , Lars Berglund , Christian Berne , Eva Lindberg
Objective
To assess how change in sleep duration is related to subsequent obesity.
Methods
In this 10-year follow-up, 4903 non-pregnant participants answered a questionnaire on sleeping habits, obesity, and lifestyle factors (questions identical to baseline questionnaire). Habitual normal sleepers were defined as sleeping 6–9 h/night at both baseline and follow-up, whereas women sleeping <6 h/night or ≥9 h/night at both occasions were defined as habitual short sleepers and habitual long sleepers, respectively. Logistic regression was used to analyze associations between changes in sleep duration, general obesity (body mass index ≥30 kg/m2), weight gain (≥10 kg) and also, central obesity (waist circumference ≥88 cm), and increase in waist circumference (≥10 cm) at follow-up.
Results
Among younger women (aged <40 years) both habitual short sleepers and habitual long sleepers had a higher prevalence of general (short: 31.3%,
P
< 0.0001; long: 38.1%,
P
= 0.01) and central obesity (short: 60.5%,
P
= 0.01; long: 82.4%,
P
= 0.01) compared with habitual normal sleepers (general obesity: 8.9%; central obesity: 35.9%) at follow-up. Younger women who were short sleepers at baseline but normal sleepers at the follow-up had a higher prevalence of both general (19.3%,
P
= 0.01) and central obesity (45.4%,
P
= 0.07) compared with habitual normal sleepers at follow-up. In adjusted analyses, both habitual short [adjusted odds ratio (aOR), 6.78; 95% confidence interval (CI), 2.71–17.0] and long (aOR, 4.64; 95% CI, 1.09–19.8) sleep durations were risk factors for general obesity in younger women. In younger women habitual long sleep duration was a risk factor also for central obesity (aOR, 6.05; 95% CI, 1.19–30.7) whereas habitual short sleep duration was not (aOR, 1.93; 95% CI, 0.87–4.81). Similar results were seen also for weight gain and increased waist circumference as dependent variables. In addition, decreased sleep duration from normal to short duration was a risk factor for both weight gain (aOR, 1.85; 95% CI, 1.14–3.02) and increased waist circumference (aOR, 1.84; 95% CI, 1.20–2.81). There were no associations between changes in sleep duration and any of the measures of obesity at the follow-up in women aged >40 years at baseline.
Conclusion
In younger women, both habitual short and long sleep duration was a risk factor for obesity, whereas no such relationship was seen in older women.
Sleep-related intermittent hypoxemia and glucose intolerance: a community-based study
Publication date:
October 2014
Source:Sleep Medicine, Volume 15, Issue 10
Author(s): Sakurako Tanno , Takeshi Tanigawa , Isao Saito , Wataru Nishida , Koutatsu Maruyama , Eri Eguchi , Susumu Sakurai , Haruhiko Osawa , Naresh M. Punjabi
Background
Intermittent hypoxemia is a fundamental pathophysiological consequence of sleep-disordered breathing and may alter glucose metabolism. To characterize the association between sleep-related intermittent hypoxemia and glucose metabolism, overnight pulse-oximetry and an oral glucose tolerance test were completed in a cohort of middle-aged and older Japanese adults.
Methods
The study sample consisted of 1836 community-dwelling Japanese (age, 30–79 years; women, 65.5%; mean body mass index, 23.1 kg/m2). The oxygen desaturation index (ODI) was quantified during sleep using a ≥3% oxygen desaturation threshold and categorized as normal (<5.0 events/h), mild (5.0–15.0 events/h), and moderate to severe (≥15.0 events/h). The independent associations between the ODI and the prevalence of impaired fasting glucose, impaired glucose tolerance, diabetes, and two metrics of insulin resistance [homeostasis model assessment index for insulin resistance (HOMA-IR) and Matsuda index] were examined.
Results
Compared with subjects with an ODI < 5 events/h, the adjusted odds ratio for prevalent impaired fasting glucose, glucose intolerance, and diabetes for subjects with an ODI ≥15.0 events/h were 1.27 (95% confidence interval, 0.72–2.23), 1.69 (1.03–2.76), and 1.28 (0.59–2.79), respectively. Both HOMA-IR and Matsuda index were significantly associated with the severity of sleep-related intermittent hypoxemia as assessed by the ODI (
P
for trend = 0.03 and 0.007, respectively).
Conclusion
Among middle-aged and older Japanese adults, sleep-related intermittent hypoxemia is associated with glucose intolerance and insulin resistance, and may contribute to the development of type 2 diabetes mellitus.
Effects of different sleep deprivation protocols on sleep perception in healthy volunteers
Publication date:
October 2014
Source:Sleep Medicine, Volume 15, Issue 10
Author(s): Leonardo I. Goulart , Luciano R. Pinto , Michael L. Perlis , Raquel Martins , Luis Otavio Caboclo , Sergio Tufik , Monica L. Andersen
Objectives
To investigate whether different protocols of sleep deprivation modify sleep perception.
Methods
The effects of total sleep deprivation (TD) and selective rapid eye movement (REM) sleep deprivation (RD) on sleep perception were analyzed in normal volunteers. Thirty-one healthy males with normal sleep were randomized to one of three conditions: (i) normal uninterrupted sleep; (ii) four nights of RD; or (iii) two nights of TD. Morning perception of total sleep time was evaluated for each condition. Sleep perception was estimated using total sleep time (in hours) as perceived by the volunteer divided by the total sleep time (in hours) measured by polysomnography (PSG). The final value of this calculation was defined as the perception index (PI).
Results
There were no significant differences among the three groups of volunteers in the total sleep time measured by PSG or in the perception of total sleep time at baseline condition. Volunteers submitted to RD exhibited lower sleep PI scores as compared with controls during the sleep deprivation period (
P
<
0.05). Both RD and TD groups showed PI similar to controls during the recovery period.
Conclusion
Selective REM sleep deprivation reduced the ability of healthy young volunteers to perceive their total sleep time when compared with time measured by PSG. The data reinforce the influence of sleep deprivation on sleep perception.
Restless legs syndrome and central nervous system gamma-aminobutyric acid: preliminary associations with periodic limb movements in sleep and restless leg syndrome symptom severity
Publication date:
October 2014
Source:Sleep Medicine, Volume 15, Issue 10
Author(s): John W. Winkelman , Laura Schoerning , Sam Platt , J.Eric Jensen
Background
Previous research has demonstrated abnormalities in glutamate and
N
-acetyl aspartate (NAA) in the thalamus in individuals with restless legs syndrome (RLS) compared with healthy matched controls. However, levels of these transmitters in other RLS-related brain areas and levels of the most common inhibitory neurotransmitter, gamma-aminobutyric acid (GABA), have not been assessed.
Methods
This study examined GABA, glutamate, and NAA levels in the dorsal anterior cingulate cortex (ACC), thalamus and cerebellum with the use of proton magnetic resonance spectroscopy (1H-MRS) at 4 tesla (4 T) and Megapress difference-editing in 18 subjects with RLS and a matched control group without RLS. Actigraphy was performed on the nights before scans to assess periodic limb movements of sleep (PLMS).
Results
Levels of GABA, glutamate, and NAA were no different between RLS and control subjects in any of the three voxels of interest. However, GABA levels were positively correlated with both PLM indices and RLS severity in the thalamus and negatively with both of these measures in the cerebellum in RLS subjects. In addition, NAA levels were higher in the ACC in RLS than in controls.
Conclusion
Our preliminary data suggest that known cerebellar–thalamic interactions may modulate the intensity of RLS sensory and motor symptoms. In addition, anterior cingulate cortex may be associated with the affective components of the painful symptoms in this disorder.
Is there a polysomnographic signature of augmentation in restless legs syndrome?
Publication date:
October 2014
Source:Sleep Medicine, Volume 15, Issue 10
Author(s): Thomas Mitterling , Birgit Frauscher , Tina Falkenstetter , Viola Gschliesser , Laura Ehrmann , David Gabelia , Elisabeth Brandauer , Werner Poewe , Birgit Högl
Objective
Augmentation of restless legs syndrome (RLS) is a potentially severe side-effect of dopaminergic treatment. Data on objective motor characteristics in augmentation are scarce. The aim of this study was to investigate in detail different variables of leg movements (LM) in untreated, treated, and augmented RLS patients.
Methods
Forty-five patients with idiopathic RLS [15 untreated, 15 treated (non-augmented), 15 augmented] underwent RLS severity assessment, one night of video-polysomnography with extended electromyographic montage, and a suggested immobilization test (SIT).
Results
Standard LM parameters as well as periodicity index (PI) and muscle recruitment pattern did not differ between the three groups. The ultradian distribution of periodic leg movements (PLM) in sleep during the night revealed significant differences only during the second hour of sleep (
P
<
0.05). However, augmented patients scored highest on RLS severity scales (
P
<
0.05) and were the only group with a substantial number of PLM during the SIT.
Conclusion
This study demonstrates that polysomnography is of limited usefulness for the diagnosis and evaluation of RLS augmentation. In contrast, the SIT showed borderline differences in PLM, and differences on subjective scales were marked. According to these results, augmentation of RLS is a phenomenon that predominantly manifests in wakefulness.
Medications associated with restless legs syndrome: a case–control study in the US Renal Data System (USRDS)
Publication date:
October 2014
Source:Sleep Medicine, Volume 15, Issue 10
Author(s): Donald L. Bliwise , Rebecca H. Zhang , Nancy G. Kutner
Objective
The objective of this study was to determine the association between the usage of four classes of “at-risk” medications (antidepressants, neuroleptics, antihistamines, and antiemetics with dopamine blockade) and restless legs syndrome (RLS) in dialysis patients within the United States Renal Data System (USRDS).
Methods
This was a case–control design within a national (United States) patient registry of all patients with end-stage renal disease (ESRD) in the USRDS anytime during the period of 1 October 2006 to 31 December 2010, inclusive. A total of 16,165 ESRD patients (3234 cases; 12,931 age-, sex-, and race-matched controls) were studied.
Results
All four classes of “at-risk” medications see widespread use among patients in the USRDS. All were associated with increased odds of an RLS diagnosis (range of odds ratios, 1.47–2.28; all
p
< 0.0001) during the period of observation. Results were unchanged when controlling for time on hemodialysis. Usage of more than one class of medication increased the odds for having RLS.
Conclusions
ESRD patients often receive medication intended for relief of conditions associated with their disease, such as depression and psychological issues, pruritus, and gastroparesis; however, such medications may increase the risk of RLS. Given the high prevalence of RLS in ESRD patients, these medications should only be used when their benefits clearly outweigh the risk of development of the troubling and distressing symptoms of RLS.
Associations of self-reported sleep disturbance and duration with academic failure in community-dwelling Swedish adolescents: Sleep and academic performance at school
Publication date:
Available online 19 September 2014
Source:Sleep Medicine
Author(s): Olga E. Titova , Pleunie S. Hogenkamp , Josefin A. Jacobsson , Inna Feldman , Helgi B. Schiöth , Christian Benedict
Objective
To examine associations of self-reported sleep disturbance and short sleep duration with the risk for academic failure.
Methods
A cohort of ~40.000 adolescents (age range: 12-19 years) who were attending high school grades seven, nine, and secondary year of upper school in the Swedish Uppsala County were invited to participate in the Swedish Life and Health Young Survey (conducted between 2005 and 2011). In addition to the question how many subjects they failed during the school year (outcome variable), subsamples of adolescents also answered questions related to subjective sleep disturbance (n=20.026) and habitual sleep duration (n=4.736) (exposure variables). Binary logistic regression analysis was utilized to explore if self-reported sleep disturbances and habitual short sleep duration (defined as less than 7-8 hours sleep per night) increase the relative risk to fail subjects during the school year (controlled for possible confounders,
e.g.
body-mass-index).
Results
Adolescents with self-reported sleep disturbances had an increased risk for academic failure (i.e., they failed at least one subject during the school year; OR: Boys, 1.68; Girls, 2.05, both P<0.001), compared to adolescents without self-reported sleep disturbances. In addition, adolescents who reported short sleep duration on both working and weekend days were more likely to fail at least one subject at school than those who slept at least 7-8 h per night (OR: Boys, 4.1; Girls, 5.0, both P<0.001).
Conclusion
Our findings indicate that reports of sleep disturbance and short sleep duration are linked to academic failure in adolescents. Importantly, based on our data, causality cannot be established.
Do periodic arm movements during sleep exist in healthy subjects? A polysomnographic study
Publication date:
September 2014
Source:Sleep Medicine, Volume 15, Issue 9
Author(s): David Gabelia , Thomas Mitterling , Birgit Högl , Gregor K. Wenning , Birgit Frauscher
Background
Despite several polysomnographic studies on periodic leg movements (PLM) in healthy sleep, data on the prevalence and characteristics of periodic arm movements (PAM) in normal subjects are lacking. We aimed to investigate PAM and their association with PLM during wakefulness and sleep in healthy subjects.
Methods
Ninety-one participants underwent video-polysomnography according to American Academy of Sleep Medicine 2007 criteria. In addition to standard electromyographic registration, data for both flexor digitorum superficialis muscles were recorded.
Results
Sixty-two subjects (68.1%) had a PAM index during wakefulness >5/h (median PAM index during wakefulness, 8.8/h; range, 0–77). Seven subjects (7.7%) had a PAM index >5/h during sleep (median PAM index during sleep, 0.7/h; range, 0–47.4). In 14% of cases, PAM during wakefulness were coincident with PLM during wakefulness. During sleep, this coincidence was not evident. The correlation between PAM and PLM was weak to moderate (during wakefulness: Spearman's
ρ
= 0.576,
P
< 0.001; during sleep: Spearman's
ρ
= 0.222,
P
= 0.036).
Conclusion
In healthy subjects, PAM occur predominantly during wakefulness with no apparent true periodicity. In contrast to classical PLM, some PAM may not present a true periodic phenomenon, but rather random voluntary movements meeting the wide range of periodicity criteria for PLM.
Sleep duration in chinese adolescents: biological, environmental, and behavioral predictors
Publication date:
Available online 22 August 2014
Source:Sleep Medicine
Author(s): Ting Chen , Zengqiang Wu , Zhifei Shen , Jun Zhang , Xiaoming Shen , Shenghui Li
Objective
To examine sleep-duration-related risk factors from multidimensional domains among Chinese adolescents.
Methods
A random sample of 4801 adolescents aged 11–20 years participated in a cross-sectional survey. A self-reported questionnaire was used to collect information about adolescents' sleep behaviors and possible related factors from eight domains.
Results
In all, 51.0% and 9.8% of adolescents did not achieve optimal sleep duration (defined as <8.0 h per day) on weekdays and on weekends, respectively. According to multivariate logistic regression models, after adjusting for all possible confounders, 17 factors were associated with sleep duration <8 h. Specifically, 13 factors from five domains were linked to physical and psychosocial condition, environment, and behaviors. These factors were overweight/obesity, chronic pain, bedtime anxiety/excitement/depression, bed/room sharing, school starting time earlier than 07:00, cram school learning, more time spent on homework on weekdays, television viewing ≥2 h/day, physical activity <1 h/day, irregular bedtime, and shorter sleep duration of father.
Conclusion
Biological and psychosocial conditions, sleep environments, school schedules, daily activity and behaviors, and parents' sleep habits significantly affect adolescents' sleep duration, indicating that the existing chronic sleep loss in adolescents could be, at least partly, intervened by improving adolescents' physical and psychosocial conditions, by controlling visual screen exposure, by regulating school schedules, by improving sleep hygiene and daytime behaviors, and by changing parents' sleep habits.
Auditory aura in nocturnal frontal lobe epilepsy: a red flag to suspect an extra-frontal epileptogenic zone
Publication date:
Available online 15 August 2014
Source:Sleep Medicine
Author(s): Lorenzo Ferri , Francesca Bisulli , Lino Nobili , Laura Tassi , Laura Lichetta , Barbara Mostacci , Carlotta Stipa , Greta Mainieri , Giorgia Bernabè , Federica Provini , Paolo Tinuper
Objective
To describe the anatomo-electro-clinical findings of patients with nocturnal hypermotor seizures (NHS) preceded by auditory symptoms, to evaluate the localizing value of auditory aura.
Methods
Our database of 165 patients with nocturnal frontal lobe epilepsy (NFLE) diagnosis confirmed by videopolysomnography (VPSG) was reviewed, selecting those who reported an auditory aura as the initial ictal symptom in at least two NHS during their lifetime.
Results
Eleven patients were selected (seven males, four females). According to the anatomo-electro-clinical data, three groups were identified. Group 1 [defined epileptogenic zone (EZ)]: three subjects were studied with stereo-EEG. The EZ lay in the left superior temporal gyrus in two cases, whereas in the third case seizures arose from a dysplastic lesion located in the left temporal lobe. One of these three patients underwent left Heschl's gyrus resection, and is currently seizure-free. Group 2 (presumed EZ): three cases in which a presumed EZ was identified; in the left temporal lobe in two cases and in the left temporal lobe extending to the insula in one subject. Group 3 (uncertain EZ): five cases had anatomo-electro-clinical correlations discordant.
Conclusions
This work suggests that auditory aura may be a helpful anamnestic feature suggesting an extra-frontal seizure origin. This finding could guide secondary investigations to improve diagnostic definition and selection of candidates for surgical treatment.
Restless legs syndrome/Willis–Ekbom disease diagnostic criteria: updated International Restless Legs Syndrome Study Group (IRLSSG) consensus criteria – history, rationale, description, and significance
Publication date:
August 2014
Source:Sleep Medicine, Volume 15, Issue 8
Author(s): Richard P. Allen , Daniel L. Picchietti , Diego Garcia-Borreguero , William G. Ondo , Arthur S. Walters , John W. Winkelman , Marco Zucconi , Raffaele Ferri , Claudia Trenkwalder , Hochang B. Lee
Background
In 2003, following a workshop at the National Institutes of Health, the International Restless Legs Syndrome Study Group (IRLSSG) developed updated diagnostic criteria for restless legs syndrome/Willis–Ekbom disease (RLS/WED). These criteria were integral to major advances in research, notably in epidemiology, biology, and treatment of RLS/WED. However, extensive review of accumulating literature based on the 2003 NIH/IRLSSG criteria led to efforts to improve the diagnostic criteria further.
Methods
The clinical standards workshop, sponsored by the WED Foundation and IRLSSG in 2008, started a four-year process for updating the diagnostic criteria. That process included a rigorous review of research advances and input from clinical experts across multiple disciplines. After broad consensus was attained, the criteria were formally approved by the IRLSSG executive committee and membership.
Results
Major changes are: (i) addition of a fifth essential criterion, differential diagnosis, to improve specificity by requiring that RLS/WED symptoms not be confused with similar symptoms from other conditions; (ii) addition of a specifier to delineate clinically significant RLS/WED; (iii) addition of course specifiers to classify RLS/WED as chronic-persistent or intermittent; and (iv) merging of the pediatric with the adult diagnostic criteria. Also discussed are supportive features and clinical aspects that are important in the diagnostic evaluation.
Conclusions
The IRLSSG consensus criteria for RLS/WED represent an international, interdisciplinary, and collaborative effort intended to improve clinical practice and promote further research.
Predictors of shorter sleep in early childhood
Publication date:
May 2014
Source:Sleep Medicine, Volume 15, Issue 5
Author(s): Laura McDonald , Jane Wardle , Clare H. Llewellyn , Cornelia H.M. van Jaarsveld , Abigail Fisher
Objective
The aim of this study was to identify socio-demographic and home environmental predictors of shorter sleep in early childhood, and to examine whether effects were mediated by the timing of bedtime or wake time.
Methods
Participants were from Gemini, a British birth cohort of twins, and included 1702 children; one randomly selected from each twin pair. Parents reported night-time sleep duration at an average age of 15.8
months (range 14–27
months) using a modified version of the Brief Infant Sleep Questionnaire. Multiple logistic regression models were used to identify predictors of shorter sleep for this study.
Results
Using a cut-off of <11
h a night, shorter sleep was reported in 14.1% of children. Lower maternal education, non-white ethnic background, being male, low birth weight, living in a home with >1 older child and watching >1
h of TV in the evening were independently associated with shorter sleep. Mediation analyses showed that associations between education, ethnicity, evening TV viewing and sleep were driven predominantly by later bedtimes, while sex differences were driven predominantly by earlier wake times in boys.
Conclusion
In this sample, multiple environmental factors were associated with shorter sleep in young children, with several operating predominantly through later bedtime. An emphasis on the importance of an early and consistent bedtime could help promote healthy sleep and reduce inequalities in child health.
Factor structure of the Chinese version of the Pittsburgh Sleep Quality Index in breast cancer patients
Publication date:
May 2014
Source:Sleep Medicine, Volume 15, Issue 5
Author(s): Rainbow T.H. Ho , Ted C.T. Fong
Objective
The Pittsburgh Sleep Quality Index (PSQI) is used extensively to assess subjective sleep disturbance in cancer populations. Although previous studies on the PSQI suggested a better fit for a two- or three-factor model than the original one-factor model, none accounted for the indicator-specific effect between sleep duration and habitual sleep efficiency. This study evaluated the PSQI’s dimensionality and its convergent validity with cancer-related psychopathological states in female breast cancer patients.
Methods
The PSQI was administered to 197 women with breast cancer. Confirmatory factor analysis examined the relative fit of one-, two-, three-, and revised one-factor models. The PSQI’s convergent validity was evaluated via bivariate correlations between the PSQI factor scores and measures of anxiety, depression, fatigue, pain, and quality of life.
Results
Confirmatory factor analyses showed an adequate fit for the revised one-factor model with the PSQI global score as the overall index of sleep disturbance. Although the revised one- and two-factor solutions showed statistically equivalent model fits, the one-factor model was selected due to utility reasons. The severity of sleep dysfunction that the PSQI global score represented was positively correlated with anxiety, depression, fatigue, pain, and reduced quality of life.
Conclusion
The results support the PSQI’s original unidimensional structure, demonstrating that the PSQI global score is a valid and parsimonious measure for assessing and screening sleep dysfunction in cancer patients.
Self-reported sleep patterns in a British population cohort
Publication date:
March 2014
Source:Sleep Medicine, Volume 15, Issue 3
Author(s): Yue Leng , Nick W.J. Wainwright , Francesco P. Cappuccio , Paul G. Surtees , Robert Luben , Nick Wareham , Carol Brayne , Kay-Tee Khaw
Objectives
Sleep patterns have been linked to various health outcomes, but sleep patterns in the British population have not been extensively reported. We aimed to describe the sleep character