| 1. |
|
|
| 2. |
|
|
| 3. |
- Eckerberg, Berndt, et al.
(författare)
-
Melatonin treatment effects on adolescent students' sleep timing and sleepiness in a placebo-controlled crossover study
- 2012
-
Ingår i: Chronobiology International. - : Informa UK Limited. - 0742-0528 .- 1525-6073. ; 29:9, s. 1239-1248
-
Tidskriftsartikel (refereegranskat)abstract
- 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.
|
|
| 4. |
- Kecklund, Göran, et al.
(författare)
-
20th International Symposium on Shiftwork and Working Time : Biological Mechanisms, Recovery, and Risk Management in the 24-h Society
- 2012
-
Ingår i: Chronobiology International. - : Informa UK Limited. - 0742-0528 .- 1525-6073. ; 29:5, s. 531-536
-
Tidskriftsartikel (refereegranskat)abstract
- This dedicated issue of Chronobiology International is devoted to the selected proceedings of the 20th International Symposium on Shift Work and Working Time held in Stockholm, Sweden, 28 June to 1 July 2011. It constitutes the fifth such issue of the journal since 2004 dedicated to the selected proceedings to the meetings of the Working Time Society. The key theme of the 20th Symposium was "Biological Mechanisms, Recovery, and Risk Management in the 24-h Society." The collection of papers of this dedicated issue represents the best of contemporary research on the effects of night and rotating shift schedules on worker health and safety. The contents cover such topics as sleep restriction, injuries, health, and performance of night work and rotating shiftwork, plus light treatment as a countermeasure against the circadian disruption of shiftwork. The majority of the papers are observational field studies, including some of large sample size, and three studies are well-designed laboratory experiments. (Author correspondence: goran.kecklund@stress.su.se ).
|
|
| 5. |
- Knutsson, Anders, et al.
(författare)
-
Shift work and diabetes - A systematic review
- 2014
-
Ingår i: Chronobiology International. - : Informa UK Limited. - 0742-0528 .- 1525-6073. ; 31:10, s. 1146-1151
-
Forskningsöversikt (refereegranskat)abstract
- Diabetes mellitus is a chronic disease, which has an increasing trend all over the world. Type 2 diabetes constitutes 90% of all diabetes. It is associated with weight gain and insulin resistance. Research during recent years has suggested that shift work could be a risk factor of type 2 diabetes. Since shift work is becoming more common, it could contribute to the increasing trend of diabetes. In this systematic review, we have studied the potential association between shift work and type 2 diabetes. We have also reviewed studies on control of diabetes in relation to shift work.
|
|
| 6. |
- Lowden, Arne, et al.
(författare)
-
Assessment of a new dynamic light regimen in a nuclear power control room without windows on quickly rotating shiftworkers-effects on health, wakefulness, and circadian alignment : a pilot study
- 2012
-
Ingår i: Chronobiology International. - : Informa UK Limited. - 0742-0528 .- 1525-6073. ; 29:5, s. 641-649
-
Tidskriftsartikel (refereegranskat)abstract
- The aim of the study was to test whether a new dynamic light regime would improve alertness, sleep, and adaptation to rotating shiftwork. The illumination level in a control room without windows at a nuclear power station was ∼200 lux (straight-forward horizontal gaze) using a weak yellow light of 200 lux, 3000 K (Philips Master TLD 36 W 830). New lighting equipment was installed in one area of the control room above the positions of the reactor operators. The new lights were shielded from the control group by a distance of >6 m, and the other operators worked at desks turned away from the new light. The new lights were designed to give three different light exposures: (i) white/blue strong light of 745 lux, 6000 K; (ii) weak yellow light of 650 lux, 4000 K; and (iii) yellow moderate light of 700 lux, 4000 K. In a crossover design, the normal and new light exposures were given during a sequence of three night shifts, two free days, two morning shifts, and one afternoon shift (NNN + MMA), with 7 wks between sessions. The operators consisted of two groups; seven reactor operators from seven work teams were at one time exposed to the new equipment and 16 other operators were used as controls. The study was conducted during winter with reduced opportunities of daylight exposure during work, after night work, or before morning work. Operators wore actigraphs, filled in a sleep/wake diary, including ratings of sleepiness on the Karolinska Sleepiness Scale (KSS) every 2 h, and provided saliva samples for analysis of melatonin at work (every 2nd h during one night shift and first 3 h during one morning shift). Results from the wake/sleep diary showed the new light treatment increased alertness during the 2nd night shift (interaction group × light × time, p < .01). Time of waking was delayed in the light condition after the 3rd night shift (group × light, p < .05), but the amount of wake time during the sleep span increased after the 2nd night shift (p < .05), also showing a tendency to affect sleep efficiency (p < .10). Effects on circadian phase were difficult to establish given the small sample size and infrequent sampling of saliva melatonin. Nonetheless, it seems that appropriate dynamic light in rooms without windows during the dark Nordic season may promote alertness, sleep, and better adaptation to quickly rotating shiftwork. (Author correspondence: arne.lowden@stress.su.se ).
|
|
| 7. |
- Ordookhani, Arash, et al.
(författare)
-
Seasonal variation of neonatal transient hyperthyrotropinemia in tehran province, 1998–2005
- 2010
-
Ingår i: Chronobiology International. - : Informa Healthcare. - 0742-0528 .- 1525-6073. ; 27:9-10, s. 1854-1869
-
Tidskriftsartikel (refereegranskat)abstract
- Seasonal aggregation and the monthly rate of neonatal transient hyperthyrotropinemia(THT) were assessed. From November 1998 to April 2005, neonates of gestationalage ≥37 wks, birth weight 2500–4000 g, birth length 45–55 cm, and 1st min Apgarscore >3, who had thyrotropin (TSH) ≥20 mU/L in their cord dried-blood specimen,but without congenital hypothyroidism, were enrolled in the study. The recall rateequals the rate of THT occurrence in this study. Of 47,945 neonates, 555 had THT(recall rate: 1.2%). The aggregated seasonal recall rate (recall for further assessment torule out congenital hypothyroidism) was significantly higher in winter (January,February, and March) than the other seasons ( p < .0001). Winter had higher recallrate in each year as compared to other seasons, but the overall rate of recalls decreasedin 2001 and 2002. Excluding the first 6 months (due to erratic variations), the remaining72 months revealed a relatively sinusoidal pattern in monthly recall rates; indeed,there was an initial 11-month high recall rates (1.7%), followed by a 33-month decrease(0.7%), a 19-month increase (1.9%), and a final 9-month decrease (0.8%). The recallrate of each of these time intervals was significantly different from that of the nexttime interval ( p < .0001). The monthly recall rates were best fitted to cubic curve estimationand then autoregressive integrated moving average (ARIMA) (0, 1, 1) models.THT occurs significantly more in winter than in other seasons, and this suggests apossible role for time-varying factor(s) contributing to its seasonal preponderance.
|
|
| 8. |
|
|
| 9. |
- van Leeuwen, Wessel M A, et al.
(författare)
-
Sleep, Sleepiness, and Neurobehavioral Performance While on Watch in a Simulated 4 Hours on/8 Hours off Maritime Watch System
- 2013
-
Ingår i: Annual Review of Chronopharmacology. - : Informa UK Limited. - 0743-9539 .- 1525-6073 .- 0742-0528. ; 30:9, s. 1108-1115
-
Tidskriftsartikel (refereegranskat)abstract
- Seafarer sleepiness jeopardizes safety at sea and has been documented as a direct or contributing factor in many maritime accidents. This study investigates sleep, sleepiness, and neurobehavioral performance in a simulated 4 h on/8 h off watch system as well as the effects of a single free watch disturbance, simulating a condition of overtime work, resulting in 16 h of work in a row and a missed sleep opportunity. Thirty bridge officers (age 30 +/- 6 yrs; 29 men) participated in bridge simulator trials on an identical 1-wk voyage in the North Sea and English Channel. The three watch teams started respectively with the 00-04, the 04-08, and the 08-12 watches. Participants rated their sleepiness every hour (Karolinska Sleepiness Scale [KSS]) and carried out a 5-min psychomotor vigilance test (PVT) test at the start and end of every watch. Polysomnography (PSG) was recorded during 6 watches in the first and the second half of the week. KSS was higher during the first (mean +/- SD: 4.0 +/- 0.2) compared with the second (3.3 +/- 0.2) watch of the day (p
|
|
| 10. |
- Åkerstedt, Torbjörn, et al.
(författare)
-
Early morning work--prevalence and relation to sleep/wake problems : a national representative survey.
- 2010
-
Ingår i: Chronobiology International. - : Informa UK Limited. - 0742-0528 .- 1525-6073. ; 27:5, s. 975-86
-
Tidskriftsartikel (refereegranskat)abstract
- Very little is known about the prevalence of morning work and its relationship with sleep and fatigue. The present study obtained data from a representative sample of the Swedish population (N = 5489) to address this limitation in the literature. The results show that 15% of the population commenced work, at least occasionally, before 05:30 h and approximately 2% did so most of the time. With the increasing phase advance of the start time, the time of rising also advanced, but bedtime changed very little. Thus, early start times were not compensated with earlier bedtimes. Total sleep time decreased as the work start time was advanced; sleep duration was <5 h for work start times between 03:00 and 04:30 h. The results also indicated that advanced start times were linked with increased fatigue, feelings of not being well rested, and reports of early start times as a rather large or very large problem. However, difficulties in waking and disturbed sleep did not change with advanced start times. It was concluded that early start times are common and are associated with sleep problems and fatigue.
|
|
