Sleep quality in adult patients with sleep related bruxism

Sleep related bruxism (SB) is the grinding of teeth during sleep and may also be associated with various sleep disorders. However, little is known about sleep structures and disturbances of SB. This study aims to further understand sleep architectures using overnight polysomnography (PSG) in patients with SB. We analyze sleep parameters and architectures in 33 healthy subjects and 25 patients with SB. PSG and sleep questionnaires measured sleep variables including proportions of rapid eye movement (REM) sleep, non-REM sleep (N1, N2 and N3), latency to sleep onset, sleep efficiency, wake after sleep onset (WASO), apnea hypopnea index (AHI), respiratory disturbance index (RDI), and periodic limb movement index (PLMI) during sleep for both groups. Sleep efficiency and the proportion of N3 in the SB group were significantly lower than in the control group (P < 0.05). In addition latency to onset of sleep and WASO were markedly increased in the SB group (P < 0.05). AHI, RDI, and PLMI showed no differences between the groups. Epworth Sleepiness Scale was significantly higher in the SB group than in the control group (P < 0.05). In contrast to previous studies, we conclude that patients with SB are not good sleepers based on PSG study. Further studies are required to assess the relationship between sleep quality and the severity of SB.

     

Short and long-term effects of unguided internet-based cognitive behavioral therapy for chronic insomnia in morning and evening persons: a post-hoc analysis

ABSTRACT

A post-hoc analysis comparing morning and evening persons with insomnia on sleep and mental health characteristics was conducted in order to investigate whether an Internet-based cognitive behavioral therapy for insomnia (ICBTi) was effective both for morning and evening persons. Adult patients (N = 178, mean age = 44.8, 67% females) with insomnia were randomized to either ICBTi (N = 92; morning persons = 41; evening persons = 51) or a web-based patient education condition (N = 86; morning persons = 44; evening persons = 42). All patients were assessed with sleep diaries, the Insomnia Severity Index (ISI), the Bergen Insomnia Scale (BIS), the Dysfunctional Beliefs and Attitudes about Sleep Scale (DBAS-16), the Hospital Anxiety and Depression Scale (HADS) and the Chalder Fatigue Scale (CFQ). Patients were characterized as morning or evening persons based on a median split on the Horne-Östberg Morningness Eveningness Questionnaire. Short and long-term effects of treatment were examined with mixed-model repeated-measures analyses. Morning and evening persons did not differ in terms of age, gender or educational status. At baseline, morning persons had more wake time after sleep onset (d= 0.54, p < .001) and more early morning awakening (d= 0.38, p < .05) compared to evening persons, while evening persons reported longer sleep onset latency (d= 0.60, p < .001), more time in bed (d= 0.56, p < .001), longer total sleep time (d= 0.45, p < .01), more fatigue (d= 0.31, p < .05) and more dysfunctional beliefs and attitudes about sleep (d= 0.47, p < .01). Despite these differences at baseline, both morning and evening persons receiving ICBTi benefitted more across most measures compared to morning and evening persons who received patient education. For morning persons in the ICBTi group, ISI scores were reduced from 17.3 at baseline to 8.8 (d_pre-post = 2.48, p < .001) at post-assessment, and to 10.0 at 18-month follow up (d_pre-post18m = 2.13, p < .001). Comparable results were found for evening persons in the ICBTi group, with a reduction in ISI scores from 17.4 at baseline to 8.6 (d_pre-post = 2.24, p < .001) at post-assessment, and to 8.7 at 18-month follow up (d_pre-post18m = 2.19, p < .001). Similar results were found on the BIS, DBAS, HADS, CFQ and sleep diary data. Despite different insomnia symptomatology between the two groups, the current study suggests that ICBTi is effective across scores on the morningness-eveningness dimension. The study was pre-registered at: ClinicalTrials.gov Identifier: NCT02261272.     

Morning Versus Evening Power Output and Repeated‐Sprint Ability

We investigated the effect of time‐of‐day on both maximal sprint power and repeated‐sprint ability (RSA). Nine volunteers (22±4 yrs) performed a RSA test both in the morning (07:00 to 09:00 h) and evening (17:00 to 19:00 h) on different days in a random order. The RSA cycle test consisted of five, 6 sec maximal sprints interspersed by 24 sec of passive recovery. Both blood lactate concentration and heart rate were higher in the evening than morning RSA (lactate values post exercise: 13±3 versus 11±3 mmol/L^?1, p<0.05). The peak power developed during the first sprint was higher in the evening than morning (958±112 vs. 915±133 W, p<0.05), but this difference was not apparent in subsequent sprints, leading to a higher power decrement across the 5×6 sec test in the evening (11±2 vs. 7±3%, p<0.05). Both the total work during the RSA cycle test and the power developed during bouts 2 to 5 failed to be influenced by time‐of‐day. This suggests that the beneficial effect of time‐of‐day may be limited to a single expression of muscular power and fails to advantage performance during repeated sprints.     

Influence of shift type on sleep quality of female nurses working monthly rotating shifts with cortisol awakening response as mediating variable

ABSTRACT

When shift nurses change shifts, it is likely to affect the cortisol patterns of their bodies and sleep quality. The objectives of this study was to verify the influence of monthly rotating day, evening and night shifts on the sleep quality of female nurses and determine whether the cortisol awakening response (CAR) mediates this relationship. A total of 132 female shift nurses were recruited, and ultimately 128 complete questionnaires and samples were obtained (subject loss rate = 3.0%) from 45 day-shift nurses, 44 evening-shift nurses and 39 night-shift nurses at a teaching hospital in Northern Taiwan. The Pittsburgh sleep quality index served as the research instrument that nurses used to collect saliva samples at home every day after waking and 30?min after waking so as to calculate the net increases in cortisol levels (CARi). Hierarchical multiple regression was employed to examine the influence of shift type on the sleep quality of the female nurses and the mediating effect of CARi. The results of this study indicate that shift type significantly influenced CARi (F = 19.66, p < 0.001) and that the regression coefficients of evening versus day shifts and night versus day shifts are both negative. Shift type also significantly influenced sleep quality (F = 15.13, p < 0.001), and the regression coefficients of evening versus day shifts and night versus day shifts are both positive. After controlling for the influence of shift type, CARi remained significantly correlated with sleep quality (ΔF = 5.17, p = 0.025). The results show that female evening-shift or night-shift nurses display significantly lower CARi and experience significantly poorer sleep quality than day-shift nurses. A greater CARi in the female shift nurses represents better sleep quality. Furthermore, the results prove that CARi is a mediating variable influencing the sleep quality of female shiftwork nurses.     

Light Exposure Among Adolescents With Delayed Sleep Phase Disorder: A Prospective Cohort Study

The objective of this study was to compare light exposure and sleep parameters between adolescents with delayed sleep phase disorder (DSPD; n?=?16, 15.3?±?1.8 yrs) and unaffected controls (n?=?22, 13.7?±?2.4 yrs) using a prospective cohort design. Participants wore wrist actigraphs with photosensors for 14 days. Mean hourly lux levels from 20:00 to 05:00?h and 05:00 to 14:00?h were examined, in addition to the 9-h intervals prior to sleep onset and after sleep offset. Sleep parameters were compared separately, and were also included as covariates within models that analyzed associations with specified light intervals. Additional covariates included group and school night status. Adolescent delayed sleep phase subjects received more evening (p?<?.02, 22:00–02:00?h) and less morning (p?<?.05, 08:00–09:00?h and 10:00–12:00?h) light than controls, but had less pre-sleep exposure with adjustments for the time of sleep onset (p?<?.03, 5–7?h prior to onset hour). No differences were identified with respect to the sleep offset interval. Increased total sleep time and later sleep offset times were associated with decreased evening (p?<?.001 and p?=?.02, respectively) and morning (p?=?.01 and p?<?.001, respectively) light exposure, and later sleep onset times were associated with increased evening exposure (p?<?.001). Increased total sleep time also correlated with increased exposure during the 9?h before sleep onset (p?=?.01), and a later sleep onset time corresponded with decreased light exposure during the same interval (p?<?.001). Outcomes persisted regardless of school night status. In conclusion, light exposure interpretation requires adjustments for sleep timing among adolescents with DSPD. Pre- and post-sleep light exposures do not appear to contribute directly to phase delays. Sensitivity to morning light may be reduced among adolescents with DSPD. (Author correspondence: auger.raymond1@mayo.edu)     

Differences in circadian phase and weekday/weekend sleep patterns in a sample of middle-aged morning types and evening types

Factors contributing to sleep timing and sleep restriction in daily life include chronotype and less flexibility in times available for sleep on scheduled days versus free days. There is some evidence that these two factors interact, with morning types and evening types reporting similar sleep need, but evening types being more likely to accumulate a sleep debt during the week and to have greater sleep extension on weekend nights. The aim of the present study was to evaluate the independent contributions of circadian phase and weekend-to-weekday variability to sleep timing in daily life. The study included 14 morning types and 14 evening types recruited from a community-based sample of New Zealand adults (mean age 41.1 ± 4.7 years). On days 1–15, the participants followed their usual routines in their own homes and daily sleep start, midpoint and end times were determined by actigraphy and sleep diaries. Days 16–17 involved a 17 h modified constant routine protocol in the laboratory (17:00 to 10:00, <20 lux) with half-hourly saliva samples assayed for melatonin. Mixed model ANCOVAs for repeated measures were used to investigate the independent relationships between sleep start and end times (separate models) and age (30–39 years versus 40–49 years), circadian phase [time of the dim light melatonin onset (DLMO)] and weekday/weekend schedules (Sunday–Thursday nights versus Friday–Saturday nights). As expected on weekdays, evening types had later sleep start times (mean = 23:47 versus 22:37, p < .0001) and end times (mean = 07:14 versus 05:56, p < .0001) than morning types. Similarly on weekend days, evening types had later sleep start times (mean = 00:14 versus 23:07, p = .0032) and end times (mean = 08:56 versus 07:04, p < .0001) than morning types. Evening types also had later DLMO (22:06 versus 20:46, p = .0002) than morning types (mean difference = 80.4 min, SE = 18.6 min). The ANCOVA models found that later sleep start times were associated with later DLMO (p = .0172) and weekend-to-weekday sleep timing variability (p < .0001), after controlling for age, while later sleep end times were associated with later DLMO (p = .0038), younger age (p = .0190) and weekend days (p < .0001). Sleep end times showed stronger association with DLMO (for every 30 min delay in DLMO, estimated mean sleep end time occurred 14.0 min later versus 10.19 min later for sleep start times). Sleep end times also showed greater delays on weekends versus weekdays (estimated mean delay for sleep end time = 84 min, for sleep start time = 28 min). Comparing morning types and evening types, the estimated contributions of the DLMO to the mean observed differences in sleep timing were on weekdays, 39% for sleep start times and 49% for sleep end times; and on weekends, 41% for sleep start times and 34% of sleep end times. We conclude that differences in sleep timing between morning types and evening types were much greater than would be predicted on the basis of the independent contribution of the difference in DLMO on both weekdays and weekend days. The timing of sleep in daily life involves complex interactions between physiological and psychosocial factors, which may be moderated by age in adults aged 30–49 years.     

Effects of circadian restricted feeding on parameters of metabolic syndrome among healthy subjects

ABSTRACT

Experimental studies indicate that energy homeostasis to the circadian clock at the behavioral, physiological, and molecular levels, emphasize that timing of food intake may play a significant role in the development of obesity and central obesity. Therefore, resetting the circadian clock by circadian energy restriction via food intake in the morning or evening, may be used as a new approach for prevention of obesity, metabolic syndrome and related diseases. After ethical clearance and written, informed consent, free living subjects were included if they volunteered to take most of the total daily meals (approximately 2000 Kcal./day) in the evening (4 weeks) or morning (4 weeks). Of 22 adults, half were randomly selected by computer generated numbers to eat in the morning and the other half in the evening, after 8.00 PM. The eating pattern was changed after 4 weeks of intervention and a 4-week washout period, those who ate in the morning were advised to eat in the evening and vice versa. Validated questionnaires were used to assess food intakes, physical activity, and intake of alcohol and tobacco. Physical examination included measurement of body weight, height, and blood pressure (BP) by sphygmomanometer. Data were regularly recorded blindly, in all subjects at start of study and during follow-up. Blood samples were collected after an overnight fast for analysis of blood glucose and Hb1c. Feeding in the evening was associated with significant increase in body weight by 0.80 kg (P < .001), body mass index (BMI) by 0.30 kg/m² (P < .001) and waist circumference by 1.13 cm (P < .05). Feeding the same amount of energy in the morning was not associated with any significant change in weight, BMI or waist circumference (P > .500). Lesser increases in all three variables were associated with AM versus PM feeding (P < .05). Systolic BP slightly increased on PM and decreased on AM feeding, with a difference between the two responses of 1.55 mmHg (P < .05). Fasting blood glucose was lower on AM than on PM feeding (74.86 vs. 77.95 mg/dl, paired t = 4.220, P < .001). Hb1C increased on PM feeding by 0.28 (from 4.45 to 4.73; t = 9.176, P < .001), but decreased on AM feeding by 0.077 (from 4.53 to 4.45; t = ?6.859, P < .001). The difference in Hb1C response between AM and PM feeding is also statistically significant (t = ?11.599, P < .001). Eating in the evening can predispose to obesity, central obesity and increases in fasting blood glucose and Hb1c that are indicators of the metabolic syndrome. By contrast, eating in the morning can decrease Hb1c and systolic BP, indicating that it may be protective against the metabolic syndrome.     

Relationships among sleep timing,sleep duration and glycemic control in Type 2 diabetes in Thailand

There is evidence that the sleep and circadian systems play a role in glucose metabolism. In addition to physiological factors, sleep is also affected by behavioral, environmental, cultural and social factors. In this study, we examined whether morning or evening preference, sleep timing and sleep duration are associated with glycemic control in patients with type 2 diabetes residing in Thailand. Two hundred and ten type 2 diabetes patients who were not shift workers completed an interview and questionnaires to collect information on diabetes history, habitual sleep duration and sleep timing. Chronotype, an individual’s tendency for being a “morning” or “evening” person, was assessed using the Composite Score of Morningness (CSM), which reflects an individual’s subjective preference for activities in the morning or evening, as well as mid-sleep time on weekend nights (MSF), which reflects their actual sleep behavior. Most recent hemoglobin A1c (HbA1c) values were retrieved from medical records. Evening preference (as indicated by lower CSM), later bedtime on weekends, and shorter sleep duration correlated with higher HbA1c (r?=??0.18, p?=?0.01; r?=?0.17, p?=?0.01 and r?=??0.17, p?=?0.01, respectively), while there was no association between MSF or wake up time and glycemic control. In addition, later bedtime on weekends significantly correlated with shorter sleep duration (r?=??0.34, p?<?0.001). Hierarchical regression analyses adjusting for age, sex, body mass index, insulin use and diabetes duration revealed that later bedtime on weekends was significantly associated with poorer glycemic control (B?=?0.018, p?=?0.02), while CSM was not. Mediation analysis revealed that this association was fully mediated by sleep duration. In summary, later bedtime on weekends was associated with shorter sleep duration and poorer glycemic control in patients with type 2 diabetes. It is likely that patients with later weekend bedtimes curtail their sleep by waking up earlier. Exploring the potential reasons for this phenomenon (e.g. cultural influences, metropolitan lifestyle, environmental factors, family and social obligations) specific to a Thai population may help identify behavioral modifications (i.e. earlier bedtime and/or sleep duration extension) that could possibly lead to improved glycemic control in this population.     

Evening physical activity alters wrist temperature circadian rhythmicity

The adequate time to perform physical activity (PA) to maintain optimal circadian system health has not been defined. We studied the influence of morning and evening PA on circadian rhythmicity in 16 women with wrist temperature (WT). Participants performed controlled PA (45?min continuous-running) during 7 days in the morning (MPA) and evening (EPA) and results were compared with a no-exercise-week (C). EPA was characterized by a lower amplitude (evening: 0.028?±?0.01?°C versus control: 0.038?±?0.016?°C; p?<?0.05) less pronounced second-harmonic (power) (evening: 0.41?±?0.47 versus morning: 1.04?±?0.59); and achrophase delay (evening: 06:35?±?02:14?h versus morning: 04:51?±?01:11?h; p?<?0.05) as compared to MPA and C. Performing PA in the late evening might not be as beneficial as in the morning.     

Evaluating the Role of Melatonin in the Long-Term Treatment of Delayed Sleep Phase Syndrome (DSPS)

Delayed sleep phase syndrome (DSPS) involves a mismatch between the usual daily schedule required by the individual's environment and his or her circadian sleep-wake pattern. Patients suffering from DSPS are treated with chronotherapy, light therapy, or melatonin administration. While chro-notherapy and light therapy are demanding and difficult treatments that usually lead to compliance problems, melatonin administration is a relatively simple and easy treatment option. Previous studies carried out on relatively small samples of DSPS patients have shown that melatonin has a sleep-promoting and entraining action when taken in the evening. The present study, which accompanied routine treatment in our sleep clinic, examined the efficiency of melatonin treatment in a relatively large population of DSPS subjects by means of subjective reports. The 61 subjects, 37 males and 24 females, were diagnosed with DSPS by means of clinical assessment and actigraphy at our sleep clinic. Their mean pretreatment falling asleep and waking times were 03: 09 (SD = 86.22 minutes) and 11: 31 (SD = 98.58 minutes), respectively. They were treated with a 6-week course of 5 mg of oral melatonin taken daily at 22: 00. A survey questionnaire was sent to the home of each subject 12–18 months after the end of the treatment; the survey investigated the efficiency of the melatonin treatment and its possible side effects. Of the patients, 96.7% reported that the melatonin treatment was helpful, with almost no side effects. Of these, 91.5% reported a relapse to their pretreatment sleeping patterns within 1 year of the end of treatment. Only 28.8% reported that the relapse occurred within 1 week. The pretreatment falling asleep and waking times of patients in whom the changes were retained for a relatively long period of time were significantly earlier than those of patients whose relapse was immediate (t = 2.18, p <. 05; t = 2.39, p <. 05, respectively), with no difference in sleep duration. The implications of these findings, as well as further research possibilities, are discussed.     

The internal circadian clock increases hunger and appetite in the evening independent of food intake and other behaviors

Objective:

Despite the extended overnight fast, paradoxically, people are typically not ravenous in the morning and breakfast is typically the smallest meal of the day. We assessed whether this paradox could be explained by an endogenous circadian influence on appetite with a morning trough, while controlling for sleep/wake and fasting/feeding effects.

Design and Methods:

Twelve healthy non‐obese adults (six males; age, 20‐42 years) were studied throughout a 13‐day laboratory protocol that balanced all behaviors, including eucaloric meals and sleep periods, evenly across the endogenous circadian cycle. Participants rated their appetite and food preferences by visual analog scales.

Results:

There was a large endogenous circadian rhythm in hunger, with the trough in the biological morning (8 AM) and peak in the biological evening (8 PM; peak‐to‐trough amplitude = 17%; P = 0.004). Similarly‐phased significant endogenous circadian rhythms were present in appetites for sweet, salty and starchy foods, fruits, meats/poultry, food overall, and for estimates of how much food participants could eat (amplitudes 14‐25%; all P < 0.05).

Conclusions:

In people who sleep at night, the intrinsic circadian evening peak in appetite may promote larger meals before the fasting period necessitated by sleep, whereas the circadian morning trough would theoretically facilitate the extended overnight fast. Furthermore, the circadian decline in hunger across the night would theoretically counteract the fasting‐induced hunger increase that could otherwise disrupt sleep.     

Melatonin ingestion after exhaustive late-evening exercise improves sleep quality and quantity,and short-term performances in teenage athletes

ABSTRACT

The present study aimed to explore the effects of a single 10-mg dose of melatonin (MEL) administration after exhaustive late-evening exercise on sleep quality and quantity, and short-term physical and cognitive performances in healthy teenagers. Ten male adolescent athletes (mean ± SD, age = 15.4 ± 0.3 years, body-mass = 60.68 ± 5.7 kg, height = 167.9 ± 6.9 cm and BMI = 21.21 ± 2.5) performed two test sessions separated by at least one week. During each session, participants completed the Yo-Yo intermittent-recovery-test level-1 (YYIRT-1) at ~20:00 h. Then, sleep polysomnography was recorded from 22:15 min to 07:00 h, after a double blind randomized order administration of a single 10-mg tablet of MEL (MEL-10 mg) or Placebo (PLA). The following morning, Hooper wellness index was administered and the participants performed the Choice Reaction Time (CRT) test, the Zazzo test and some short-term physical exercises (YYIRT-1, vertical and horizontal Jumps (VJ; HJ), Hand grip strength (HG), and five-jump test (5-JT)). Evening total distance covered in the YYIRT-1 did not change during the two conditions (p > 0.05). Total sleep time (Δ = 24.55 mn; p < 0.001), sleep efficiency (Δ = 4.47%; p < 0.001), stage-3 sleep (N3 sleep) (Δ = 1.73%; p < 0.05) and rapid-eye-movement sleep (Δ = 2.15%; p < 0.001) were significantly higher with MEL in comparison with PLA. Moreover, sleep-onset-latency (Δ = –8.45mn; p < 0.001), total time of nocturnal awakenings after sleep-onset (NA) (Δ = –11 mn; p < 0.001), stage-1 sleep (N1 sleep) (Δ = –1.7%; p < 0.001) and stage-2 sleep (N2 sleep) (Δ = ?1.9%; p < 0.05) durations were lower with MEL. The Hooper index showed a better subjective sleep quality, a decrease of the subjective perception of fatigue and a reduced level of muscle soreness with MEL. Moreover, MEL improved speed and performance but not inaccuracy during the Zazzo test. CRT was faster with MEL. Morning YYIRT-1 (Δ = 82 m; p < 0.001) and 5-JT (Δ = 0.08 m; p < 0.05) performances were significantly higher with MEL in comparison with PLA. In contrast, HG, VJ and HJ performances did not change during the two conditions (p > 0.05). The administration of a single dose of MEL-10 mg after strenuous late-evening exercise improved sleep quality and quantity, selective attention, subjective assessment of the general wellness state, and some short-term physical performances the following morning in healthy teenagers.     

Chronopharmacology of Oral Nitrates in Healthy Subjects

The pharmacokinetics and the hemodynamic effects (blood pressure, heart rate) of oral organic nitrates have been investigated in healthy subjects after oral single-dose application either in the morning or in the evening. Isosorbide-5- monitrate (IS-SMN, 60 rng) was administered as an immediate-release tablet or as a slow-release formulation. Isosorbide dinitrate (ISDN, 20 mg) was ingested as an immediate-release tablet. After administration of IS-5-MN as an immediate-release tablet, the drug was more rapidly absorbed in the morning (t_max of 0.9 h) than in the evening (t_max of 2.1 h). The rapid absorption led to more pronounced effects in the morning, at which time maximum drug concentrations occurred at the same time as peak effects were observed. After evening administration, however, peak effects were in advance of the maximum drug concentrations. No chronokinetics were observed after application of the slow-release formulation of IS-5- MN. In accordance with the results of the immediate-release formulation, peak effects of the slow-release preparation occurred significantly earlier than peak drug concentrations after evening than after morning dosing. ISDN bioavailability was higher after morning than after evening administration and hemodynamic effects were more pronounced in the evening than in the morning. These results show that daily variations in pharmacokinetics and/or hemodynamic effects can be observed with oral nitrates. In addition, galenic formulation can influence the time-specified pharmacokinetics of IS-5-MN.     

Associations between chronotype,morbidity and mortality in the UK Biobank cohort

Later chronotype (i.e. evening preference) and later timing of sleep have been associated with greater morbidity, including higher rates of metabolic dysfunction and cardiovascular disease (CVD). However, no one has examined whether chronotype is associated with mortality risk to date. Our objective was to test the hypothesis that being an evening type is associated with increased mortality in a large cohort study, the UK Biobank. Our analysis included 433 268 adults aged 38–73 at the time of enrolment and an average 6.5-year follow-up. The primary exposure was chronotype, as assessed through a single self-reported question-defining participants as definite morning types, moderate morning types, moderate evening types or definite evening types. The primary outcomes were all-cause mortality and mortality due to CVD. Prevalent disease was also compared among the chronotype groups. Analyses were adjusted for age, sex, ethnicity, smoking, body mass index, sleep duration, socioeconomic status and comorbidities. Greater eveningness, particularly being a definite evening type, was significantly associated with a higher prevalence of all comorbidities. Comparing definite evening type to definite morning type, the associations were strongest for psychological disorders (OR 1.94, 95% CI 1.86–2.02, p = < 0.001), followed by diabetes (OR 1.30, 95% CI 1.24–1.36, p = < 0.001), neurological disorders (OR 1.25, 95% CI 1.20–1.30, p = < 0.001), gastrointestinal/abdominal disorders (OR 1.23, 95% CI 1.19–1.27, p = < 0.001) and respiratory disorders (OR 1.22, 95% CI 1.18–1.26, p = < 0.001). The total number of deaths was 10 534, out of which 2127 were due to CVD. Greater eveningness, based on chronotype as an ordinal variable, was associated with a small increased risk of all-cause mortality (HR 1.02, 95% CI 1.004–1.05, p = 0.017) and CVD mortality (HR 1.04, 95% CI 1.00–1.09, p = 0.06). Compared to definite morning types, definite evening types had significantly increased risk of all-cause mortality (HR 1.10, 95% CI 1.02–1.18, p = 0.012). This first report of increased mortality in evening types is consistent with previous reports of increased levels of cardiometabolic risk factors in this group. Mortality risk in evening types may be due to behavioural, psychological and physiological risk factors, many of which may be attributable to chronic misalignment between internal physiological timing and externally imposed timing of work and social activities. These findings suggest the need for researching possible interventions aimed at either modifying circadian rhythms in individuals or at allowing evening types greater working hour flexibility.     

Melatonin Treatment Effects on Adolescent Students' Sleep Timing and Sleepiness in a Placebo-Controlled Crossover Study

During the last few decades, the incidence of sleep-onset insomnia, due to delay of circadian phase, has increased substantially among adolescents all over the world. We wanted to investigate whether a small dose of melatonin given daily, administered in the afternoon, could advance the sleep timing in teenagers. Twenty-one students, aged 14–19 yrs, with sleep-onset difficulties during school weeks were recruited. The study was a randomized, double blind, placebo (PL)-controlled crossover trial, lasting 5 wks. During the first 6 d in wks 2 and 4, the students received either PL or melatonin (1 mg) capsules between 16:30 and 18:00 h. During the first 6 d of wk 5, all students received melatonin. Wks 1 and 3 were capsule-free. In the last evening of each week and the following morning, the students produced saliva samples at home for later melatonin analysis. The samples were produced the same time each week, as late as possible in the evening and as early as possible in the morning. Both the student and one parent received automatic mobile text messages 15 min before saliva sampling times and capsule intake at agreed times. Diaries with registration of presumed sleep, subjective sleepiness during the day (Karolinska Sleepiness Scale, KSS) and times for capsule intake and saliva samplings were completed each day. Primary analysis over 5 wks gave significant results for melatonin, sleep and KSS. Post hoc analysis showed that reported sleep-onset times were advanced after melatonin school weeks compared with PL school weeks (p < .005) and that sleep length was longer (p < .05). After the last melatonin school week, the students fell asleep 68 min earlier and slept 62 min longer each night compared with the baseline week. Morning melatonin values in saliva diminished compared with PL (p < .001) and evening values increased (p < .001), indicating a possible sleep phase advance. Compared with PL school weeks, the students reported less wake up (p < .05), less school daytime sleepiness (p < .05) and increased evening sleepiness (p < .005) during melatonin weeks. We conclude that a small dose of melatonin given daily, administered in the afternoon, could advance the sleep timing and make the students more alert during school days even if they continued their often irregular sleep habits during weekends. (Author correspondence: arne.lowden@stress.su.se)     

Differences in morning–evening type and sleep duration between Black and White adults: Results from a propensity-matched UK Biobank sample

Biological evidence suggests that ethno-racial differences in morning–evening type are possible, whereby Blacks may be more likely to be morning type compared to Whites. However, population-level evidence of ethno-racial difference in morning–evening type is limited. In an earlier study, we reported that morning type was more prevalent in Blacks compared to Whites in the United Kingdom (UK) Biobank cohort (N = 439 933). This study aimed to determine if these ethno-racial differences persisted after accounting for an even broader range of social, environmental and individual characteristics and employing an analytic approach that simulates randomization in observational data, propensity score modeling. Data from UK Biobank participants whose self-identified race/ethnicity was Black/Black British or White; who did not report daytime napping, shift work or night shift work; who provided full mental health information; and who were identified using propensity score matching were used (N = 2044). Each sample was strongly matched across all social, environmental and individual characteristics as indicated by absolute standardized mean differences <0.09 for all variables. The prevalence of reporting nocturnal short, adequate and long sleep as well as morning, intermediate and evening type among Blacks (n = 1022) was compared with a matched sample of Whites (n = 1022) using multinomial logistic regression models. Blacks had a 62% greater odds of being morning type [odds ratio (OR) = 1.620, 95% confidence interval (CI): 1.336–1.964, p < .0001] and a more than threefold greater odds of reporting nocturnal short sleep (OR = 3.453, 95% CI: 2.846–4.190, p < .0001) than Whites. These data indicate that the greater prevalence of morning type and short nocturnal sleep in Blacks compared to Whites is not fully explained by a wide range of social and environmental factors. If sleep is an upstream determinant of health, these data suggest that ethno-racially targeted public health sleep intervention strategies are needed.     

Exposure to screens of digital media devices,sleep, and concentration abilities in a sample of Israel adults

A major consequence of the invasion of digital media devices with screens equipped with light-emitting diode (LED) into bedrooms exposes the users to ongoing short wavelength (SWL) lighting during the evening and at night when under natural conditions, long wavelength are dominant. Results of several studies reveal a negative physiological, behavioral, and functional outcome of the exposure to SWL artificial light at night (ALAN) from digital media screens. The aims of our study are to assess the relationships between digital media usage, sleep patterns, subjective sleepiness, and attention abilities in adult Israeli citizens compared with Israeli adolescents. We recruited 280 adult participants using convenience sample method, 49% males and 51% females with an age range of 18–82. The participants filled out self-reporting novel and original questionnaires as follows: demographic, general health evaluation, sleep habits, and difficulties by the Pittsburgh Sleep Quality Index (PSQI) and the Karolinska Sleepiness Scale (KSS), prevalence, and usage patterns of digital media devices. Smartphones are the most used digital media device in the evening and after bedtime (the time one gets to sleep in bed). Israeli adults used smartphones for 30 min and TV for about 15 min after bedtime. We noted that excessive exposure to these devices at nighttime was associated with longer sleep latency (r = 0.192, p < 0.01) and decreased sleep hours (r = − 0.143, p < 0.05). Moreover, we found a negative correlation between attention abilities in the morning and the usage time of digital media at nighttime (r = − 0.155, p < 0.01). Exposure to digital screens at evening and nighttime was positively correlated with subjective sleepiness on the KSS (r = 0.135, p < 0.05, and r = 0.261, p < 0.01). To the best of our knowledge, this study is the first to explore the association between digital media screens usage, sleep, and concentration abilities in the Israeli adult.

     

Morning‐to‐Evening Differences in Oxygen Uptake Kinetics in Short‐Duration Cycling Exercise

This study analyzed diurnal variations in oxygen (O₂) uptake kinetics and efficiency during a moderate cycle ergometer exercise. Fourteen physically active diurnally active male subjects (age 23±5 yrs) not specifically trained at cycling first completed a test to determine their ventilatory threshold (T_vent) and maximal oxygen consumption (VO_2max); one week later, they completed four bouts of testing in the morning and evening in a random order, each separated by at least 24 h. For each period of the day (07:00–08:30 h and 19:00–20:30 h), subjects performed two bouts. Each bout was composed of a 5 min cycling exercise at 45 W, followed after 5 min rest by a 10 min cycling exercise at 80% of the power output associated with T_vent. Gas exchanges were analyzed breath‐by‐breath and fitted using a mono‐exponential function. During moderate exercise, the time constant and amplitude of VO₂ kinetics were significantly higher in the morning compared to the evening. The net efficiency increased from the morning to evening (17.3±4 vs. 20.5±2%; p<0.05), and the variability of cycling cadence was greater during the morning than evening (+34%; p<0.05). These findings suggest that VO₂ responses are affected by the time of day and could be related to variability in muscle activity pattern.     

The effect of protein supplement source or supply pattern on the intake,digestibility, rumen kinetics,nitrogen utilisation and growth of Ethiopian Menz sheep fed teff straw

A series of trials were conducted to study the effect of either nitrogen source or supply pattern on the growth, rumen fermentation pattern and utilisation of straw by Ethiopian Menz sheep. All experimental sheep were given teff straw basal diet (CON). Irrespective of the trial, treatment sheep were offered either cottonseed cake (CSC), leucaena (LEU) and sesbania (SESM) in the morning prior to teff straw. Additional treatments with sesbaia were offered either in the evening (SESE) or morning and evening (SESME). Measurements included roughage intake, digestibility, kinetics, rumen fermentation patterns, nitrogen utilisation, microbial protein supply and growth of sheep.Rate of degradation was highest (P < 0.05) when sesbania was offered once a day compared with twice a day, while supplementation produced higher (P < 0.05) liquid passage rates. Diets with sesbania produced higher (P < 0.05) roughage intake compared with leucaena. Microbial protein supply as well as N economy were similar (P > 0.05) among the foliage diets irrespective of source, time or frequency of feeding. Supplementation enhanced (P < 0.001) growth rates in sheep, while cottonseed cake (CSC) diet was superior (P < 0.01) to the fodder trees. Growth rates declined across treatments during the second phase (6–10 weeks) compared with the initial period (1–6 weeks). It is also possible for farmers to feed sesbania supplements in the morning or evening or twice daily without any detrimental effects.     

Chrysin ameliorates ANTU‐induced pulmonary edema and pulmonary arterial hypertension via modulation of VEGF and eNOs

Alpha‐naphthylthiourea (ANTU), a rodenticide induces lung toxicity. Chrysin a flavonoid possesses antioxidant, anti‐inflammatory, and antihypertensive potential. The aim of this study was to evaluate the efficacy of chrysin against ANTU‐induced pulmonary edema (PE) and pulmonary arterial hypertension (PAH) in laboratory rats. Sprague‐Dawley rats were used to induce PE (ANTU, 10 mg/kg, ip) and PAH (ANTU, 5 mg/kg, ip, 4 weeks). Animals were treated with chrysin (10, 20, and 40 mg/kg) and various biochemical, molecular, and histological parameters were evaluated. Acute administration of ANTU induces PE revealed by significant (P < 0.05) increase in relative lung weight, pleural effusion volume, lung edema, bronchoalveolar lavage fluid cell counts, total protein, 5‐hydroxytryptamine (5‐HT), lactate dehydrogenase (LDH), and γ‐glutamyl transferase (GGT), whereas pretreatment with chrysin (20 and 40 mg/kg, ip) significantly (P < 0.05) attenuated these ANTU‐induced biochemical and histological alterations. Repeated administration of ANTU caused induction of PAH evaluated by significant (P < 0.05) alterations in electrocardiographic, hemodynamic changes, and left ventricular function, whereas chrysin (20 and 40 mg/kg, p.o.) treatment significantly (P < 0.05) attenuated these alterations. ANTU‐induced hematological and serum biochemical (aspartate transaminase, alanine transaminase, LDH, and creatinine kinase MB) alterations were significantly (P < 0.05) inhibited by chrysin. It also significantly (P < 0.05) decreased elevated levels of oxido‐nitrosative stress in the right ventricle (RV) and lung. Chrysin significantly (P < 0.05) attenuated downregulated endothelial nitric oxide synthase and upregulated vascular endothelial growth factor messenger RNA and protein expressions both in the RV and pulmonary artery. Chrysin inhibited ANTU‐induced PE and PAH via modulation of inflammatory responses (5‐HT, LDH, and GGT), oxido‐nitrosative stress, and VEGF and eNOs levels.