Population-based analysis of sociodemographic predictors, health-related quality of life and health service use associated with obstructive sleep apnoea and insomnia in Australia.

Although there is growing recognition of the effects of living with sleep disorders and the important role of primary care in their identification and management, studies indicate that the detection of sleep apnoea (OSA) and insomnia may still be low. This large representative community-based study (n=2977 adults) used logistic regression models to examine predictors of self-reported OSA and current insomnia and linear regression models to examine the association of these sleep conditions with both mental and physical components of health-related quality of life (HRQoL) and health service use. Overall, 5.6% (95% confidence interval (CI) 4.6-6.7) and 6.8% (95% CI 5.7-7.9) of subjects self-reported OSA (using a single-item question) and current insomnia (using two single-item questions) respectively. Many sociodemographic and lifestyle predictors for OSA and insomnia acted in different directions or showed different magnitudes of association. Both disorders had a similar adverse relationship with physical HRQoL, whereas mental HRQoL was more impaired among those with insomnia. Frequent consultations with a doctor were associated with a lower physical HRQoL across these sleep conditions; however, lower mental HRQoL among those frequently visiting a doctor was observed only among individuals with insomnia. The adverse relationship between sleep disorders and physical and mental HRQoL was substantial and should not be underestimated.

Perception versus Reality: The Relationship between Subjective and Objective Measures of Sleep When On-call under Simulated Laboratory Conditions.

BACKGROUND: On-call working arrangements have been shown to negatively impact sleep. However, workers may perceive their sleep to be worse than it actually is. The aim of this study was to compare participants' pre- and post-sleep estimates of sleep duration and sleep quality with objectively measured sleep when on-call under laboratory conditions. PARTICIPANTS: 72 healthy, adult males. METHODS: Analyses were performed on three interrelated studies, all of which consisted of four nights in a sleep laboratory. Following adaptation and baseline nights were two on-call nights (sleep opportunity 23:00 h - 07:00 h). Before and after each sleep opportunity, participants provided subjective estimates of sleep. Sleep was objectively measured using polysomnography. RESULTS: Estimated sleep duration (6.74 ± 1.13 h) and sleep onset latency (20.55 ± 14.85 min) were significantly poorer than objectively measured sleep outcomes (sleep duration 7.21 ± 1.25 h; sleep latency 13.20 ± 10.06 min). Of the variance in post-sleep estimated sleep duration, 14% was associated with objectively measured minutes of N3 (R2Δ = 0.55) and REM (R2Δ = 0.75). Additionally, 14% of post-sleep sleep quality estimation variance was associated with minutes of N2 (R2Δ = 0.60) and N3 (R2Δ = 0.79), measured by polysomnography. CONCLUSIONS: Some objective measures of sleep were associated with subjective estimates of sleep duration and sleep quality. However, individuals may overestimate sleep onset latency and underestimate sleep duration during on-call periods. It may be beneficial for on-call workers to actively reflect on feelings of fatigue/alertness for workplace fatigue management, rather than relying solely on estimates of sleep.

Waking qEEG to assess psychophysiological stress and alertness during simulated on-call conditions.

INTRODUCTION: On-call schedules are associated with stress and disrupted sleep. In a recent study, under non-sleep deprived conditions, low and high-stress on-call conditions did not significantly impact sleep quality but did impact next day performance. Our aim was to determine whether quantitative electroencephalography (qEEG) would reflect changes in cortical activity in on-call conditions, predicting that the high-stress condition would display faster qEEG frequencies compared with the control and low-stress condition. METHODS: Twenty-four healthy male participants (age: 26.5 ±â€¯4.0 yrs) spent four nights in a time-isolated sleep laboratory. The within-subjects, repeated measures experimental design assessed waking EEG, via the Karolinska Drowsiness Test (KDT) during four time-points across a control day and two experimental (on-call) days. Experimental days comprised a low-stress (LS - reading task) and high-stress (HS - speech task) condition and were counterbalanced. Mixed-models analysis was used to assess condition and time by EEG biomarkers: Alpha Attenuation Coefficient (AAC), Slowing Ratio (SR) and Scaling Exponent (SE). RESULTS: Main effects were found for all three biomarkers by condition, with pairwise analysis reported. There was a significant difference in AAC between the LS condition (M = 1.26 ±â€¯=1.24) and HS condition (M = 1.01 ±â€¯0.76 p = .02) indicating decreased alertness between LS and HS. A significant increase in SR between control (M = 7.1 ±â€¯4.3) and LS (M = 10.1 ±â€¯8.5 p = .0001), and a significant increase between the LS and HS (M = 7.8 ±â€¯6.8 p = .018) showing greatest EEG slowing in the LS condition, reflecting of a passive, sleepier brain state. The SE was significantly higher in the LS (M = 1.09, ±0.17) condition compared with control (M = 1.0, ±0.11 p = .001) indicating decreased alertness in the LS task. DISCUSSION: Using qEEG biomarkers, in contrast with our initial hypothesis, the current study found that compared with control, the LS condition resulted in greater EEG slowing. These findings have implications for on-call workers who engage in periods of passive attention and highlight a protective role task stress may play in maintaining alertness levels during on-call conditions.

Community engagement in general practice: a qualitative study.

BACKGROUND Community engagement is believed to be an important component of quality primary health care. We aimed to capture specific examples of community engagement by general practices, and to understand the barriers that prevent engagement. METHODS We conducted 20 distinct interviews with 31 key informants from general practice and the wider community. The interviews were semi-structured around key relevant topics and were analysed thematically. RESULTS Key themes identified from the interview transcripts included an understanding of 'community', examples of community engagement and the perceived benefits and barriers to community-engaged general practice. We particularly explored aspects of community engagement with Maori. CONCLUSIONS General practices in the study do not think in terms of communities, and they do not have a systematic framework for engagement. Although local champions have generated some great initiatives, most practices seemed to lack a conceptual framework for engagement: who to engage with, how to engage with them, and how to evaluate the results of the engagement.

Chronobiology of sleep in humans.

Periodic circadian (24-h) cycles play an important role in daily hormonal and behavioural rhythms. Usually our sleep/wake cycle, temperature and melatonin rhythms are internally synchronized with a stable phase relationship. When there is a desynchrony between the sleep/wake cycle and circadian rhythm, sleep disorders such as advanced and delayed sleep phase syndrome can arise as well as transient chronobiologic disturbances, for example from jet lag and shift work. Appropriately timed bright light is effective in re-timing the circadian rhythm and sleep pattern to a more desired time, ameliorating these disturbances. Other less potent retiming effects may also be obtained from the judicious use of melatonin and exercise.

Sleep-disordered breathing in Prader-Willi syndrome and its association with neurobehavioral abnormalities.

OBJECTIVES: To determine the prevalence and type of sleep-disordered breathing among patients with Prader-Willi syndrome (PWS) and its relationship to such neurobehavioral abnormalities as mental retardation, obsessive-compulsive behavior, and conduct disorders. STUDY DESIGN: Polysomnography (PSG) studies were conducted in 13 unselected subjects with PWS (age 1.5 to 28 years). PSG results were compared with tests of behavior and cognition (Development Behavior Checklist [DBC], Auditory Continuous Performance Test [ACPT], and Wechsler Intelligence Scale appropriate for age). RESULTS: Nine of 13 (69%) subjects had > 10 apneas and hypopneas per hour of sleep. Apart from a 2-year-old subject with normal body weight who demonstrated severe central hypopnea in rapid eye movement sleep, the sleep-breathing disturbance was due to upper airway obstruction. Age-adjusted body mass index was associated with more severe hypoxemia during sleep (min SaO2, r = -.87, P < .005) and more sleep disruption (arousals/hour of sleep, r = .62, P < .05; sleep efficiency, r = -.66, P < .05). Increasing severity of obstructive sleep apnea (OSA) or sleep disturbance was associated with daytime inactivity/sleepiness and autistic-relating behavior (DBC) and with impulsiveness (ACPT). Unexpectedly, sleep hypoxemia appeared to be predictive of increased performance IQ. CONCLUSIONS: OSA is prevalent among subjects with PWS and is associated with increased body mass, daytime inactivity/ sleepiness, and some behavioral disturbances.

Light emitting diodes can be used to phase delay the melatonin rhythm.

Two portable light sources, comprising light emitting diodes (LEDs) of two different wavelengths, were compared to a standard light box in suppressing and phase shifting nocturnal salivary melatonin. All light sources were equated for illuminance of 2000 lux. Sixty-six volunteers participated in the 2-day study and were randomly allocated to one of four conditions; light box, white LED, blue/green LED, or no light control group. Light was administered to the experimental groups from midnight to 02.00 hr on the first night. Half-hourly saliva samples were collected from 19.00 to 02.00 hr on night 1 and until 01.00 hr on night 2. Percent melatonin suppression on night 1 and dim light melatonin onset (DLMO) for each night were calculated. The experimental groups showed significant melatonin suppression during light stimulation, with the blue/green LEDs producing the greatest (70%) suppression. There was no significant difference between the light box at 63% and white LED at 50% suppression. Similarly, the blue/green LED had a significantly greater DLMO delay of 42 min and no difference between the light box of 23 min and the white LED of 22 min. These data suggest the portable LED light source is an effective way of delivering light to phase shift the melatonin rhythm, with the blue/green LED being the more effective of the two LEDs.

The short-term benefits of brief and long naps following nocturnal sleep restriction.

STUDY OBJECTIVES: The purpose was to remedy the lack of experimental studies directly comparing the effects of brief and long daytime naps following nocturnal sleep restriction. DESIGN: Twelve young adult healthy sleepers participated in a repeated measures design comparing the effects of no nap, a 10-minute nap, and a 30-minute afternoon nap in each case following a night of 4.7 hours of total sleep time. Objective and subjective alertness measures and cognitive performance measures were taken before, then 5, 35, and 60 minutes after the termination of the nap. SETTING: N/A. PARTICIPANTS: N/A. INTERVENTIONS: N/A. MEASUREMENTS AND RESULTS: In the no nap condition measures showed either no change or a decreases of alertness and performance across the testing period. Following the 10-minute nap there was an immediate improvement in subjective alertness and cognitive performance which was sustained for the hour of post nap testing. Immediately following the 30 minute nap most measures of alertness and performance declined but showed some recovery by the end of testing. CONCLUSIONS: Because the delayed benefits following the 30-minute nap may be due to sleep inertia, longer post-nap testing periods should be investigated. However, we conclude that the detrimental effects of sleep restriction were more rapidly and significantly ameliorated, at least within the hour following the nap, by a 10-minute afternoon nap.

Effect of light wavelength on suppression and phase delay of the melatonin rhythm.

Different wavelengths of light were compared for melatonin suppression and phase shifting of the salivary melatonin rhythm. The wavelengths compared were 660 nm (red), 595 nm (amber), 525 nm (green), 497 nm (blue/green), and 470 nm (blue). They were administered with light-emitting diodes equated for irradiance of 130 muW/cm2. Fifteen volunteers participated in all five wavelength conditions and a no light control condition, with each condition conducted over two consecutive evenings. Half-hourly saliva sam ples were collected from 19:00 to 02:00 on night 1 and until 01:00 on night 2. Light was administered for the experimental conditions on the first night only from midnight to 02:00. Percentage melatonin suppression on night 1 and dim light melatonin onset (DLMO) for each night were calculated. The shorter wavelengths of 470, 497, and 525 nm showed the greatest melatonin suppression, 65% to 81%. The shorter wavelengths also showed the greatest DLMO delay on night 2, ranging from 27 to 36 min. The results were consistent with the involvement of a scotopic mechanism in the regulation of circadian phase.

Core body temperature is elevated during constant wakefulness in elderly poor sleepers.

STUDY OBJECTIVES: The aim of this study was to test for heightened physiological activity in elderly poor sleeepers compared to good sleepers under ad lib sleep and constant wakeful conditions. DESIGN AND SETTING: Subjects participated in a five-day protocol consisting of four nights of polysomnographic (PSG) and rectal temperature monitoring followed by 26 hours of continuous rectal temperature monitoring under controlled constant wakefulness. PARTICIPANTS: Participants were 16 self-reported sleep maintenance insomniacs and 16 self-reported good sleeping controls over 55 years of age. INTERVENTIONS: NA. MEASUREMENT AND RESULTS: Subjects were grouped according to (1) subjective sleep status and (2) into quartiles according to amount of PSG determined wake after sleep onset (WASO). Significant group differences in temperature were observed when subjects were classified according to PSG but not subjective criteria. In the former case, subjects with the lowest (bottom quartile) compared to the highest (top quartile) amount of PSG determined WASO showed lower sleep and nighttime constant wakeful core body temperatures. CONCLUSIONS: In the elderly, elevated core body temperature is associated with increased nocturnal wakefulness suggesting that physiological activation may underlie sleep maintenance insomnia. This was clearly significant when subjects were compared using objective criteria and temperature was collected under constant wakeful conditions.

Urinary 6-sulfatoxymelatonin excretion and aging: new results and a critical review of the literature.

The apparent age-related decline in melatonin production has been thought to continue in a secular manner across the lifespan. While it is clear that melatonin levels in children and adolescents are elevated compared to older individuals, the question of whether there is a sudden or gradual change has not been adequately addressed. In this study, we report the excretion of the melatonin metabolite, 6-sulfatoxymelatonin in 253 subjects aged between 21 and 82 yr. The correlation with age was significant (r = -0.24; P < 0.05). When the data was analysed by ANOVA using 5-yr age spans, there was a significant effect of age, but post hoc analysis indicated that after 25 yr of age there was no significant decline in excretion of the metabolite. Thus, although the oldest subjects excreted 36% less melatonin metabolite than the youngest, the decrease occurred at a very early age. In the second part of the study, we re-evaluated the data from seven previous studies that measured plasma melatonin levels or metabolite excretion across a wide range of ages and 11 studies comparing young versus older subjects. Statistical analysis by ANOVA again suggested that the changes in melatonin occurring with age were essentially complete before 30 yr of age. The youngest subjects produced at the most twice the amount of melatonin as the oldest subjects. Finally, we evaluated the mean plasma melatonin levels in 144 groups of normal subjects reported in 137 separate publications with respect to age. Again, whereas there was a significant correlation with age, ANOVA showed that there was no difference between groups after 35 yr of age, and the oldest groups had levels that were only 43% of the youngest groups. We conclude that melatonin production is lower in older people, but that the change occurs very early in life, around 20-30 yr of age.

The relationship between 6-sulphatoxymelatonin and polysomnographic sleep in good sleeping controls and wake maintenance insomniacs, aged 55-80 years.

The pineal hormone, melatonin, is reported to possess hypnotic properties. This has led to an investigation of the relationship between the endogenous melatonin rhythm and sleep. However, this relationship has yet to be fully examined in aged insomniacs and controls. From media advertisements, 16 good sleeping controls (11F, 5M) and 16 sleep maintenance insomniacs (11F, 5M), aged over 55 years, were recruited to participate in a study involving four nights of polysomnographically (PSG) measured sleep followed by a 26 h constant routine. During the constant routine, 2 h urine samples were collected and analysed for the melatonin metabolite, 6-sulphatoxymelatonin (aMT.6S). This was used to determine total melatonin excretion. As well, the following circadian melatonin parameters were calculated from fifth order polynomial curve fitting analyses, the goodness of the polynomial curve fit, peak melatonin concentration, the phase of the melatonin rhythm, and melatonin and sleep rhythm synchrony. Apart for one control, all subjects showed significant circadian melatonin rhythms. Although insomniacs showed a greater amount of wakefulness, less sleep in total, and lower sleep efficiency, no significant group differences were observed in any of the melatonin parameters. In addition, while subjects with more reliable melatonin curve fits showed shorter sleep latencies and higher sleep efficiencies, correlational analyses revealed no other significant relationships between any melatonin and PSG sleep parameters. Overall, the present results suggest that neither melatonin amplitude nor phase are related to sleep quality in the aged.

6-Sulfatoxymelatonin excretion and self-reported sleep in good sleeping controls and 55-80-year-old insomniacs.

The pineal hormone melatonin is thought to play a role in sleep initiation and maintenance. This was examined in a large sample of good sleeping controls (n = 52) and sleep maintenance insomniacs (n = 56), aged 55-80 y. Subjects collected 5 d of self-reported sleep diary measures, and 12-h urine samples (08.00-20.00 and 20.00-08.00 h) for analysis of the urinary melatonin metabolite, 6-sulphatoxymelatonin (aMT.6S). Insomniacs reported a significantly greater amount of wake after sleep onset, less sleep in total, less efficient sleep and poorer quality sleep compared to controls. However, no significant differences in melatonin excretion were observed between controls and insomniacs, with both groups showing similar mean (SEM) 12-h night-time [30.9 (2.9) vs. 30.6 (3.3) nmoles, respectively] as well as 24-h total [38.7 (3.4) vs. 36.7 (3.8)] aMT.6S excretion levels. No significant correlations were observed with any sleep parameters nor any effects of medication (anti-inflammatory agents, hormone replacement therapy, and an undifferentiated group of medications). The present results do not support a simple relationship between total melatonin production and self-reported sleep quality and duration in the aged.

The pupillary light reflex cannot be used to measure sleepiness.

The pupillary light reflex (PLR) has been considered by some researchers to be responsive to changes in levels of sleepiness. However, no previous studies have tested this hypothesis with the dramatic variation of sleepiness across a complete circadian cycle. In this experiment, 20 normal individuals (age: 18-48 years) underwent a 27-hr constant routine, during which they were kept awake except for a 15-min nap opportunity every hour. Sleepiness was assessed both subjectively, by the Stanford Sleepiness Scale, and objectively, by a modified version of the Multiple Sleep Latency Test. The PLR in response to a flash of light was recorded every 2 hr, immediately before a nap period. Results showed that baseline pupil diameter became smaller with progressive sleep restriction, but there were no changes in any of the parameters of the PLR despite significant fluctuations in sleepiness. Some of the changes in the PLR were significantly related to changes in baseline pupil diameter. When baseline diameter was partialled out, there was still no effect of sleepiness on the PLR. The results suggest that the PLR cannot be used as a measure of sleepiness.

Daytime melatonin administration in elderly good and poor sleepers: effects on core body temperature and sleep latency.

Melatonin has been shown to have hypnotic and hypothermic effects in young adults and has been proposed as treatment for insomnia. However, the hypnotic and thermoregulatory effects of melatonin remain to be simultaneously investigated for aged good and poor sleepers. The aim of this study was to explore the short-term effects of exogenous oral daytime melatonin on core body temperature, sleep latency, and subjective vigor and affect in aged women. Twelve sleep maintenance insomniacs and 10 good sleeping postmenopausal female subjects [mean (SD) age = 65.2 (7.4) years] participated in a double-blind, crossover study in which they received a capsule containing either melatonin (5 mg) or a placebo at 1400 hours. Continuous core body temperature and hourly multiple sleep latency tests (MSLT) were collected from 1100-2030 hours. Self-reported estimates of global vigor (sleepiness) and affect were collected prior to each MSLT using visual analog scales. Comparison of good and poor sleepers failed to reveal any significant differences in core body temperature, sleep latency, or subjective vigor and affect. However, for both groups combined, melatonin administration [absolute postadministration mean (SEM) = 36.9 (0.05) degrees C] significantly lowered core body temperature compared with placebo [37.1 (0.05) degrees C]. Similarly, melatonin administration significantly reduced latency to stage 1 (SOL1) and stage 2 (SOL2) [absolute postadministration mean SOL1 = 20.1 (1.7) and SOL2 = 20.7 (1.6) minutes] compared with placebo [SOL1 = 24.3 (1.2) and SOL2 = 25.2 (1.1) minutes]. Treatment had no significant effect on either vigor or affect. Overall, our results suggest that although short-term exogenous oral daytime melatonin has significant hypothermic and hypnotic effects in aged women, the size of the effects is modest.

Urinary 6-sulfatoxymelatonin cycle-to-cycle variability.

For either clinical or research purposes, the timing of the nocturnal onset in production of the urinary melatonin metabolite 6-sulfatoxymelatonin (UaMT6s-onset), has been proposed as a reliable and robust marker of circadian phase. However, given that most circadian rhythms show cycle-to-cycle variability, the statistical reliability of phase estimates obtained from a single study using UaMT6s-onset remains to be determined. Following 2 weeks of sleep diary and wrist actigraphy, 15 young, healthy good sleepers participated in four UaMT6s sampling sessions spaced 1 day apart. During the sampling sessions subjects remained indoors under low light conditions and hourly urine samples were collected from 19:00 to 02:00 h. Samples were subsequently assayed for UaMT6s using standard radioimmunographic techniques. UaMT6s-onset was determined by the time at which melatonin production exceeded the average of three proceeding trials by 100%. Sleep onset times were derived from sleep diary and actigraphic measures taken before the melatonin collection nights. We found that there was no significant variation between nights in group mean UaMT6s-onset times, and intraindividual variability was small. In addition, UaMT6s-onset times were highly and significantly correlated between nights (grand mean r = 0.804). Our results suggest that within 95% confidence interval limits, individual UaMT6s-onset estimates obtained from a single night UaMT6s-onset study can be used to predict subsequent UaMT6s-onset times within +/- 97 min. A close temporal relationship was also found between the timing of UaMT6s-onset and sleep onset. Overall, our results suggest that under entrained conditions single-session UaMT6s-onset studies can provide reliable individual UaMT6s-onset phase estimates and that the protocol described in this study is a practical and noninvasive methodology.

Circadian rhythms of early morning awakening insomniacs.

It has been suggested that two types of insomnia, sleep onset insomnia and early morning awakening insomnia, may be caused by delays and advances respectively of circadian rhythms. Evidence supports the circadian rhythm phase delay of sleep onset insomniacs. The present study investigated the phase timing of circadian rhythms of early morning awakening insomniacs compared with a group of age matched good sleepers. A 24-h bed rest laboratory session was used to evaluate the endogenous core body temperature and urinary melatonin rhythms. Objective and subjective sleepiness were also measured every 30 min across the session with 10 min multiple sleep latency tests and Stanford Sleepiness Scale. Maximum and minimum phases of each individual's rhythm were identified using two-component cosine curve fitting. Compared with the good sleepers, the insomniacs had significant phase advances of 2-4 h for the temperature and melatonin rhythms. However, the 0-4 h advances of the sleepiness rhythms were not significant. This latter unexpected result was explained on the basis of variability of sleepiness measures. It was suggested that early morning awakening insomnia arises from phase advanced circadian rhythms which evoke early arousal's from sleep.

The rhythms of human sleep propensity and core body temperature.

Evidence from human free-running studies has suggested a close relationship between the timing of the circadian rhythm of core body temperature and the rhythm of sleep propensity. However, this relationship may be questioned by variations of sleep and wakeful activity which could have masked the endogenous temperature rhythm. A constant routine was used here to 'unmask' the endogenous temperature rhythm in addition to frequent sleep trials across a 24-h period to confirm the relationship between temperature and sleep propensity rhythms. Of the 14 healthy, good sleeping subjects 13 had significant 24-h cosine rhythms of sleep propensity. Eight of these also had a significant 12-h cosine rhythm. The eight subjects with both 24-h and 12-h rhythms showed a minor peak of sleep propensity in the early afternoon followed by a though in the early evening (20.00 hours). Sleep propensity then rose rapidly at about midnight to a major peak in the early morning. This was followed by a second trough of sleep propensity in the late morning. The average times of the sleep propensity phases relative to the circadian temperature rhythm were very similar to the earlier free-running studies. Furthermore, the times of the sleep propensity phases were highly correlated with the body temperature minimum. These results suggested the possibility that a common oscillator determines the timing of both the body temperature rhythm and the phases of the sleep propensity rhythm.