| 1. |
- Akerstedt, Torbjörn, et al.
(författare)
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Accounting for partial sleep deprivation and cumulative sleepiness in the Three-Process Model of alertness regulation.
- 2008
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Ingår i: Chronobiol Int. - : Informa UK Limited. - 1525-6073 .- 0742-0528. ; 25:2, s. 309-19
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Tidskriftsartikel (refereegranskat)abstract
- Accounting for partial sleep deprivation and cumulative sleepiness in the Three-Process Model of alertness regulation.Akerstedt T, Ingre M, Kecklund G, Folkard S, Axelsson J.Stress Research Institute, University of Stockholm, Stockholm, Sweden. torbjorn.akerstedt@ki.seMathematical models designed to predict alertness or performance have been developed primarily as tools for evaluating work and/or sleep-wake schedules that deviate from the traditional daytime orientation. In general, these models cope well with the acute changes resulting from an abnormal sleep but have difficulties handling sleep restriction across longer periods. The reason is that the function representing recovery is too steep--usually exponentially so--and with increasing sleep loss, the steepness increases, resulting in too rapid recovery. The present study focused on refining the Three-Process Model of alertness regulation. We used an experiment with 4 h of sleep/night (nine participants) that included subjective self-ratings of sleepiness every hour. To evaluate the model at the individual subject level, a set of mixed-effect regression analyses were performed using subjective sleepiness as the dependent variable. These mixed models estimate a fixed effect (group mean) and a random effect that accounts for heterogeneity between participants in the overall level of sleepiness (i.e., a random intercept). Using this technique, a point was sought on the exponential recovery function that would explain maximum variance in subjective sleepiness by switching to a linear function. The resulting point explaining the highest amount of variance was 12.2 on the 1-21 unit scale. It was concluded that the accumulation of sleep loss effects on subjective sleepiness may be accounted for by making the recovery function linear below a certain point on the otherwise exponential function.
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| 2. |
- Akerstedt, Torbjörn, et al.
(författare)
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Disturbed sleep in shift workers, day workers, and insomniacs.
- 2008
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Ingår i: Chronobiol Int. - : Informa UK Limited. - 1525-6073 .- 0742-0528. ; 25:2, s. 333-48
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Tidskriftsartikel (refereegranskat)abstract
- Disturbed sleep in shift workers, day workers, and insomniacs.Akerstedt T, Ingre M, Broman JE, Kecklund G.Stress Research Institute, University of Stockholm, Karolinska Institutet, Stockholm, Sweden. torbjorn.akerstedt@ki.seVery little is known about differences in sleep between day and shift workers in representative samples of the population. This study compared a national representative sample (N=3400) of shift (with night shifts) and day workers regarding the different types of sleep disturbances and also the level of sleep symptoms with that of insomnia patients. The results showed very few differences between shift and day workers; only "too little sleep" and "nodding off at work" were marginally higher among shift workers. The results also showed that the complaints of insomnia patients for most sleep disturbances corresponded to the 2nd-16th percentile of the shift workers' levels of complaints. The results suggest, at least with the present questionnaire methodology, that shift work does not appear to be a major source of sleep disturbances and that their complaint levels bear no resemblance to those seen in insomniac patients.
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| 3. |
- Akerstedt, Torbjörn, et al.
(författare)
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Sleep homeostasis during repeated sleep restriction and recovery : support from EEG dynamics.
- 2009
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Ingår i: Sleep. - : Oxford University Press (OUP). - 0161-8105 .- 1550-9109. ; 32:2, s. 217-22
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Tidskriftsartikel (refereegranskat)abstract
- STUDY OBJECTIVES: Sleep reduction normally causes a homeostatic response during subsequent recovery sleep, but this does not seem to be true for repeated partial sleep loss. The aim of the present study was to test the response to repeated partial sleep loss through detailed focus on spectral data and parts of sleep. DESIGN: The experiment involved 4 h of sleep across 5 days in the laboratory (partial sleep deprivation [PSD]), followed by 3 days of recovery sleep. PSD was achieved through a delayed bedtime. Nine individuals participated. To avoid "laboratory monotony," subjects were permitted to leave the lab for a few hours each day. MEASUREMENTS AND RESULTS: All sleep stages and the latencies to sleep and slow wave sleep (SWS) showed a significant reduction during PSD. However, SWS and TST (total sleep time) during the first half of sleep increased gradually across days with PSD. During the first recovery sleep, SWS was significantly increased, while stage 1 and latency to stage 3 were reduced. All were back to baseline on the second night of recovery sleep. Summed spectral power during the first 3.8 h of sleep showed a gradual and robust increase (50% above baseline) in the range 1.25-7.25 Hz across days with PSD up to first recovery sleep and then returned to baseline. CONCLUSIONS: SWS and summed power density in a broad low-frequency band respond to repeated partial sleep deprivation in a dose-response fashion during the first 4 h sleep, apparently reflecting a robust and stable homeostatic response to sleep loss.
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| 4. |
- Anund, Anna, 1964-, et al.
(författare)
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Bussförares arbetstider kopplat till trötthet
- 2014
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Bussförare i kollektivtrafiken har ofta oregelbundna arbetstider och en arbetssituation som kan innebära hög stress. Dessa faktorer kan leda till allvarlig trötthet. Syftet med denna studie är att belysa hur arbetstiden påverkar sömn, stress, trötthet och körförmåga. Projektet omfattar fyra delstudier: enkätstudie, sömndagböcker och aktigrafi, analys av schemaläggning och ett experiment på riktig väg med bussförare. Hypoteserna var att tidiga morgonturer, delade skift, långa arbetsdagar och få timmars vila mellan arbetspassen bidrar till trötthet, stress och nedsatt körförmåga, som tillsammans kan leda till en sämre säkerhet. De övergripande resultaten stödjer dessa hypoteser. Generellt sett upplevs sömnighet och trötthet under körning som ett problem eftersom förarna anser att detta innebär nedsatt körförmåga, vilket ökar risken för incidenter och olyckor. Totalt 45 procent av förarna hade minst två gånger i månaden svårt att hålla sig vakna när de kör buss och 19 procent hade under det senaste decenniet varit inblandade i en incident där trötthet varit en bidragande orsak. Experimentet med delade skift med tidig start på morgonen stöder dessa rön. Rapporten avslutas med en lista med förslag.
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| 5. |
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| 6. |
- Axelsson, John, et al.
(författare)
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Beauty sleep : experimental study on the perceived health and attractiveness of sleep deprived people
- 2010
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Ingår i: The BMJ. - : BMJ. - 1756-1833. ; 341
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Tidskriftsartikel (refereegranskat)abstract
- Our findings show that sleep deprived people appear less healthy, less attractive, and more tired compared with when they are well rested. This suggests that humans are sensitive to sleep related facial cues, with potential implications for social and clinical judgments and behaviour. Studies are warranted for understanding how these effects may affect clinical decision making and can add knowledge with direct implications in a medical context.
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| 7. |
- Axelsson, John, et al.
(författare)
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Effects of acutely displaced sleep on testosterone.
- 2005
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Ingår i: J Clin Endocrinol Metab. - : The Endocrine Society. - 0021-972X .- 1945-7197. ; 90:8, s. 4530-5
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Tidskriftsartikel (refereegranskat)abstract
- CONTEXT: It is not yet clear whether the diurnal variation in testosterone is regulated by circadian or homeostatic (sleep) influences. OBJECTIVE: The present study tested whether testosterone is driven by a circadian-independent sleep effect by shifting sleep acutely to daytime in a 24-h sampling regiment. DESIGN, SETTING, AND PARTICIPANTS: In the sleep laboratory, seven healthy young men (age, 22-32 yr) participated in three conditions: habituation (sleep between 2300-0700 h), night sleep (2300-0700 h), and day sleep (0700-1500 h), the latter two in a balanced order. INTERVENTION AND MAIN OUTCOME MEASURE: Serum testosterone was, in all conditions, sampled by hourly blood drawing for 24 h during constant bed rest. RESULTS: Mean testosterone levels increased as a log-linear function of time (hours) across both sleep periods (b = 4.88; P < 0.001), from 15.3 +/- 2.1 to 25.3 +/- 2.2 nmol/liter during night sleep and from 17.3 +/- 2.1 to 26.4 +/- 2.9 nmol/liter during day sleep. Similarly, mean testosterone levels decreased with time (log-linear) awake (b = -1.80; P < 0.001). There was also evidence of a weak circadian component (acrophase ranging between 0651-0924 h) and an increase with time in the laboratory. Moreover, all these effects, except for the increase during sleep, differed significantly between individuals. CONCLUSION: In conclusion, testosterone increased during sleep and fell during waking, whereas circadian effects seemed marginal. Individual differences were pronounced.
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| 8. |
- Axelsson, John, et al.
(författare)
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Sleepiness and performance in response to repeated sleep restriction and subsequent recovery during semi-laboratory conditions.
- 2008
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Ingår i: Chronobiol Int. - : Informa UK Limited. - 1525-6073 .- 0742-0528. ; 25:2, s. 297-308
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Tidskriftsartikel (refereegranskat)abstract
- Sleepiness and performance in response to repeated sleep restriction and subsequent recovery during semi-laboratory conditions.Axelsson J, Kecklund G, Akerstedt T, Donofrio P, Lekander M, Ingre M.Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden. john.axelsson@ki.seThere is an ongoing debate of how best to measure the effects of sleep loss in a reliable and feasible way, partly because well controlled laboratory studies and field studies have come to different conclusions. The aims of the present study were to investigate both sleepiness and performance in response to long-term sleep restriction and recovery in a semi-laboratory environment, investigate order effects (i.e., whether levels return to baseline) in a study with seven days of recovery, and characterize individual differences in tolerance to restricted sleep. Nine healthy men (age 23-28 yrs) participated in the protocol, which included one habituation day (sleep 23:00-07:00 h), two baseline days (23:00-07:00 h), five days with restricted sleep (03:00-07:00 h), and seven recovery days (23:00-07:00 h). Participants went outdoors at least twice each day. Reaction-time tests were performed at 08:00, 14:00, and 20:00 h each day in the laboratory. Sleepiness was self-rated by the Karolinska Sleepiness Scale (KSS)after each test. The mixed-effect regression models showed that each day of restricted sleep resulted in an increase of sleepiness by 0.64+/- .05 KSS units (a nine-step scale, p < .001), increase of median reaction times of 6.6+/- 1.6 ms ( p = .003), and increase of lapses/test of 0.69 +/- .16 ms ( p < .001). Seven days of recovery allowed participants to return to the baseline for sleepiness and median reaction time, but not for lapses.The individual differences were larger for performance measures than for sleepiness; the between-subject standard deviation for the random intercept was in the magnitude of the effects of 1.1 days of restricted sleep for sleepiness, 6.6 days of restricted sleep for median reaction time, and 3.2 days for lapses. In conclusion, the present study shows that sleepiness is closely related to sleep pressure, while performance measures, to a larger extent, appear determined by specific individual traits. Moreover, it is suggested to measure sleepiness in a standardized situation so as to minimize the influences of contextual factors.
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| 9. |
- Axelsson, John, et al.
(författare)
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Sleepiness as motivation : a potential mechanism for how sleep deprivation affects behavior
- 2020
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Ingår i: Sleep. - : Oxford University Press (OUP). - 0161-8105 .- 1550-9109. ; 43:6
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Tidskriftsartikel (refereegranskat)abstract
- STUDY OBJECTIVES: To determine how sleepiness and sleep deprivation drive the motivation to engage in different behaviors.METHODS: We studied the sleepiness of 123 participants who had been randomized to sleep deprivation or normal sleep, and their willingness to engage in a range of everyday behaviors.RESULTS: Self-reported sleepiness was a strong predictor of the motivation to engage in sleep-preparatory behaviors such as shutting one's eyes (OR=2.78, 95%CI: 2.19-3.52 for each step up on the Karolinska Sleepiness Scale) and resting (OR=3.20, CI: 2.46-4.16). Sleepiness was also related to the desire to be cared for by a loved one (OR=1.49, CI: 1.22-1.82), and preparedness to utilize monetary and energy resources to get to sleep. Conversely, increased sleepiness was associated with a decreased motivation for social and physical activities (e.g., be with friends OR=0.71, CI: 0.61-0.82; exercise OR=0.65, CI: 0.56-0.76). Sleep deprivation had similar effects as sleepiness on these behaviors. Neither sleepiness nor sleep deprivation had strong associations with hunger, thirst, or food preferences.CONCLUSIONS: Our findings indicate that sleepiness is a dynamic motivational drive that promotes sleep-preparatory behaviors and competes with other drives and desired outcomes. Consequently, sleepiness may be a central mechanism by which impaired alertness, e.g., due to insufficient sleep, contributes to poor quality of life and adverse health. We propose that sleepiness helps organize behaviors toward the specific goal of assuring sufficient sleep, in competition with other needs and incentives. A theoretical framework on sleepiness and its behavioral consequences are likely to improve our understanding of several disease mechanisms.
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| 10. |
- Chungkham, Holendro Singh, et al.
(författare)
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Factor Structure and Longitudinal Measurement Invariance of the Demand Control Support Model : An Evidence from the Swedish Longitudinal Occupational Survey of Health (SLOSH)
- 2013
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 8:8
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: To examine the factor structure and to evaluate the longitudinal measurement invariance of the demand-control-support questionnaire (DCSQ), using the Swedish Longitudinal Occupational Survey of Health (SLOSH).METHODS: A confirmatory factor analysis (CFA) and multi-group confirmatory factor analysis (MGCFA) models within the framework of structural equation modeling (SEM) have been used to examine the factor structure and invariance across time.RESULTS: FOUR FACTORS: psychological demand, skill discretion, decision authority and social support, were confirmed by CFA at baseline, with the best fit obtained by removing the item repetitive work of skill discretion. A measurement error correlation (0.42) between work fast and work intensively for psychological demands was also detected. Acceptable composite reliability measures were obtained except for skill discretion (0.68). The invariance of the same factor structure was established, but caution in comparing mean levels of factors over time is warranted as lack of intercept invariance was evident. However, partial intercept invariance was established for work intensively.CONCLUSION: Our findings indicate that skill discretion and decision authority represent two distinct constructs in the retained model. However removing the item repetitive work along with either work fast or work intensively would improve model fit. Care should also be taken while making comparisons in the constructs across time. Further research should investigate invariance across occupations or socio-economic classes.
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| 11. |
- Couthouis, Julien, et al.
(författare)
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A yeast functional screen predicts new candidate ALS disease genes
- 2011
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 108:52, s. 20881-20890
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Tidskriftsartikel (refereegranskat)abstract
- Amyotrophic lateral sclerosis (ALS) is a devastating and universally fatal neurodegenerative disease. Mutations in two related RNA-binding proteins, TDP-43 and FUS, that harbor prion-like domains, cause some forms of ALS. There are at least 213 human proteins harboring RNA recognition motifs, including FUS and TDP-43, raising the possibility that additional RNA-binding proteins might contribute to ALS pathogenesis. We performed a systematic survey of these proteins to find additional candidates similar to TDP-43 and FUS, followed by bioinformatics to predict prion-like domains in a subset of them. We sequenced one of the segenes, TAF15, in patients with ALS and identified missense variants, which were absent in a large number of healthy controls. These disease-associated variants of TAF15 caused formation of cytoplasmic foci when expressed in primary cultures of spinal cord neurons. Very similar to TDP-43 and FUS, TAF15 aggregated in vitro and conferred neurodegeneration in Drosophila, with the ALS-linked variants having amore severe effect than wild type. Immunohistochemistry of postmortem spinal cord tissue revealed mislocalization of TAF15 in motor neurons of patients with ALS. We propose that aggregation-prone RNA-binding proteins might contribute very broadly to ALS pathogenesis and the genes identified in our yeast functional screen, coupled with prion-like domain prediction analysis, now provide a powerful resource to facilitate ALS disease gene discovery.
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| 12. |
- Ekstedt, Mirjam, et al.
(författare)
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Sleep, physical activity and BMI in six to ten-year-old children measured by accelerometry: a cross-sectional study.
- 2013
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Ingår i: International Journal of Behavioral Nutrition and Physical Activity. - : Springer Science and Business Media LLC. - 1479-5868. ; 22:10, s. 82-89
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND:The aim of this study is to describe the relationship between objective measures of sleep, physical activity and BMI in Swedish pre-adolescents. The day-to-day association between physical activity and sleep quality as well as week-day and weekend pattern of sleep is also described.METHOD:We conducted a cross sectional study consisted of a cohort of 1.231 children aged six to ten years within the Stockholm county area. Sleep and physical activity were measured by accelerometry during seven consecutive days. Outcome measures are total sleep time, sleep efficiency, sleep start and sleep end; physical activity intensity divided into: sedentary (<1.5 METS), light (1.5 to 3 METS) and moderate-to-vigorous (> 3 METS); and Body Mass Index standard deviations score, BMIsds.RESULTS:Total sleep time decreased with increasing age, and was shorter in boys than girls on both weekdays and weekends. Late bedtime but consistent wake-up time during weekends made total sleep time shorter on weekends than on weekdays. Day-to-day within-subject analysis revealed that moderate-to-vigorous intense physical activity promoted an increased sleep efficiency the following night (CI < 0.001 to 0.047), while total sleep time was not affected (CI -0.003 to 0.043). Neither sleep duration (CI -0.024 to 0.022) nor sleep efficiency (CI -0.019 to 0.028) affected mean physical activity level the subsequent day. The between-subject analysis indicates that the sleep of children characterized by high moderate-to-vigorous physical activity during the day was frequently interrupted (SE = -.23, P < .01). A negative association between BMIsds and sleep duration was found (-.10, p < .01).CONCLUSIONS:Short sleep duration was associated with high BMI in six to ten year old children. This study underscores the importance of consistent bedtimes throughout the week for promoting sleep duration in preadolescents. Furthermore, this study suggests that a large proportion of intensive physical activity during the day might promote good sleep quality.
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| 13. |
- Holding, Benjamin C., et al.
(författare)
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Quantifying Cognitive Impairment After Sleep Deprivation at Different Times of Day : A Proof of Concept Using Ultra-Short Smartphone-Based Tests
- 2021
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Ingår i: Frontiers in Behavioral Neuroscience. - : Frontiers Media SA. - 1662-5153. ; 15
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Tidskriftsartikel (refereegranskat)abstract
- Cognitive functioning is known to be impaired following sleep deprivation and to fluctuate depending on the time of day. However, most methods of assessing cognitive performance remain impractical for environments outside of the lab. This study investigated whether 2-min smartphone-based versions of commonly used cognitive tests could be used to assess the effects of sleep deprivation and time of day on diverse cognitive functions. After three nights of normal sleep, participants (N = 182) were randomised to either one night of sleep deprivation or a fourth night of normal sleep. Using the Karolinska WakeApp (KWA), participants completed a battery of 2-min cognitive tests, including measures of attention, arithmetic ability, episodic memory, working memory, and a Stroop test for cognitive conflict and behavioural adjustment. A baseline measurement was completed at 22:30 h, followed by three measurements the following day at approximately 08:00 h, 12:30 h, and 16:30 h. Sleep deprivation led to performance impairments in attention, arithmetic ability, episodic memory, and working memory. No effect of sleep deprivation was observed in the Stroop test. There were variations in attention and arithmetic test performance across different times of day. The effect of sleep deprivation on all cognitive tests was also found to vary at different times of day. In conclusion, this study shows that the KWA's 2-min cognitive tests can be used to detect cognitive impairments following sleep deprivation, and fluctuations in cognitive performance relating to time of day. The results demonstrate the potential of using brief smartphone-based tasks to measure a variety of cognitive abilities within sleep and fatigue research.
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| 14. |
- Ingre, Michael, et al.
(författare)
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Estimating statistical power, posterior probability and publication bias of psychological research using the observed replication rate
- 2018
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Ingår i: Royal Society Open Science. - : The Royal Society. - 2054-5703. ; 5:9
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, we show how Bayes' theorem can be used to better understand the implications of the 36% reproducibility rate of published psychological findings reported by the Open Science Collaboration. We demonstrate a method to assess publication bias and show that the observed reproducibility rate was not consistent with an unbiased literature. We estimate a plausible range for the prior probability of this body of research, suggesting expected statistical power in the original studies of 48-75%, producing (positive) findings that were expected to be true 41-62% of the time. Publication bias was large, assuming a literature with 90% positive findings, indicating that negative evidence was expected to have been observed 55-98 times before one negative result was published. These findings imply that even when studied associations are truly NULL, we expect the literature to be dominated by statistically significant findings.
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| 15. |
- Ingre, Michael, et al.
(författare)
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Overcoming Knowledge Resistance : A Systematic Review of Experimental Studies
- 2022
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Ingår i: Knowledge Resistance in High-Choice Information Environments. - London : Routledge. - 9781003111474 ; , s. 254-280
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Bokkapitel (refereegranskat)abstract
- Research shows that our reasoning often is motivated by desires to view the world as we want it to be, and that such motivated reasoning is an important factor behind knowledge resistance. In the current chapter, we review research examining cures for knowledge resistance, specifically for the rebuttal of available facts based on the best evidence. The review included 26 studies reported in 17 papers. The results indicate that there are techniques that to some extent can reduce knowledge resistance. A consistent finding was that people are more open to fact messages framed to be compatible with their worldview or expressed in gain rather than loss terms. Prompting a focus on messages’ explanatory power also decreases the rejection of facts that are in opposition with an individual's motivations. Other techniques show promising results but need to be explored further. In sum, the results suggest a set of strategies to counter biased reasoning, some of which should be possible to use in applied communication contexts. However, further experimental research on this topic using is warranted to replicate and extend current findings.
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| 16. |
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| 17. |
- Ingre, Michael, 1965-
(författare)
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P-hacking in academic research : a critical review of the job strain model and of the association between night work and breast cancer in women
- 2017
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- P-hacking can be described as a more or less deliberate, explorative approach to data analysis with a flexible/opportunistic search space and the reporting of primarily statistically significant findings. This leads to inflated type-1 error rates and to bias in reported estimates in the scientific literature.This thesis aims to describe how p-hacking can be manifested in academic research and to illustrate how bias due to p-hacking is expected to affect the veracity of published findings using two specific examples from the literature. This thesis also argues that when evaluating published findings in the current academic environment, we should assume a priori that biases due to p-hacking and publication bias are present.The thesis used Monte Carlo simulations and systematic reviews of the literature in two specific fields: the proposed associations between exposure to night work and breast cancer in women, and between job strain and coronary heart disease.A general model and mathematical framework to predict expected bias from p-hacking was developed, and can be used for a priori defined protected inferences of any published finding, under explicit assumptions of various levels of p-hacking. The model indicated a close to 100% chance of demonstrating a false positive association in larger studies, but also showed that even minimal p-hacking results in substantial bias in estimates.The literature review identified large flexibility in the analytical process, allowing for the final model to be picked from a large pool of available models, with an implied search space of thousands of estimates. Some of the specific observations made here could be used to argue evidence for high risk of p-hacking and publication bias in the reviewed literature:None of the 17 reviewed studies on job strain and coronary heart disease reported the proper estimate of the job strain interaction (chapter 6) and our analysis showed that the proper estimate would not have been statistically significant in any of the studies (chapter 7).One study described a data driven approach with an implied search space of at least 502 models, where adjusting for confounding did not reduce the strength of the association, as would be expected, but instead increased its strength so it fell above the threshold for statistical significance (chapter 5).One study was based on a speculative and marginally significant estimate after arbitrarily restricting the analysis to a subgroup, when estimates on the full group were available and indicated a non-significant association (chapter 5).Statistical power analyses on research into night work and breast cancer indicated that statistically significant findings were over-represented in the literature (p≈.001) suggesting the presence of bias from p-hacking or selective publishing of significant findings (chapter 5).The findings also suggest that previously reported estimates in meta-analyses was likely to represent prevailing bias in the two fields reviewed here. A bias-adjusted meta-analysis on the job strain model and coronary heart disease with a total of 462,220 subjects and 6,836 CHD events indicated no support for the job strain interaction (RR=1.00; 95% CI: 0.88--1.14). In addition, it did not show an increased risk due to high job demand (RR=1.03; 95% CI: 0.97--1.11) but it did confirm previously reported risks due to low job control (RR=1.11; 95% CI: 1.03--1.20).
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| 18. |
- Ingre, Michael, et al.
(författare)
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Periodic self-rostering in shift work : correspondence between objective work hours, work hour preferences (personal fit), and work schedule satisfaction
- 2012
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Ingår i: Scandinavian Journal of Work, Environment and Health. - : Scandinavian Journal of Work, Environment and Health. - 0355-3140 .- 1795-990X. ; 38:4, s. 327-336
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Tidskriftsartikel (refereegranskat)abstract
- Objectives The main objective of the present study was to investigate relative personal fit as the association between rated needs and preferences for work hours, on the one hand, and actual work hours, on the other hand, in three groups (hospital, call-center, and police) working with periodic self-rostering. We also examined the association between personal fit and satisfaction with the work schedule and preference for a fixed and regular shift schedule, respectively. Methods We collected questionnaire data and objective work hour data over 6-12 months from the computerized self-rostering system. The response rate of the questionnaire was 69% at the hospital and call-center and 98% among the police. In total, 29 433 shifts for 285 shift workers were included in the study. Data was analyzed by means of mixed ANOVA, Kendal tau correlations and ordinal (proportional odds) logistic regression. Results The results show that evening types worked relatively more hours during the evening and night hours compared to morning types as an indication of relative personal fit. Relative personal fit was also found for long shift, short rest, and morning-, evening- and night-shift frequency, but only personal fit related to morning, evening and night-shift was associated with satisfaction with work hours. Reported conflicts at the workplace about work hours and problems with lack of predictability of time for family/leisure activities, was associated with poor satisfaction and a preference for a fixed shift schedule. Conclusions The present study shows that periodic self-rostering is associated with relative personal fit, in particular with respect to night, evening, and morning work. Personal fit seems to be associated with satisfaction with work hours and may be a moderator of tolerance to shift work exposure.
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| 19. |
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| 20. |
- Ingre, Michael, et al.
(författare)
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Sleep length as a function of morning shift-start time in irregular shift schedules for train drivers : self-rated health and individual differences.
- 2008
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Ingår i: Chronobiol Int. - : Informa UK Limited. - 1525-6073 .- 0742-0528. ; 25:2, s. 349-58
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Tidskriftsartikel (refereegranskat)abstract
- Sleep length as a function of morning shift-start time in irregular shift schedules for train drivers: self-rated health and individual differences.Ingre M, Kecklund G, Akerstedt T, Söderström M, Kecklund L.Stress Research Institute, Stockholm University, Sweden. michael.ingre@stressforskning.su.seForty-six male train drivers (mean age = 46.5, SD = 5.1) were recruited to participate in a diary study for 14 consecutive days with questions about their sleep and working hours. A polynomial mixed-effect regression model showed a curvilinear relation ( p < .001) between shift-start time and sleep duration for shifts starting at 03:00-12:00 hand with a near linear increase for ones starting between 04:30 and 09:00 h of approximately 0.7 h for every 1 h the shift was delayed. The longest sleeps were estimated at approximately 8 h before shifts that started at approximately 10:00 h. The shortest sleeps were found for shifts that started before 04:30 h and were estimated at approximately 5 h. Individual differences were estimated with a random-effect standard deviation of 0.51 h, independent of shift start time ( p = .005). One-half of the between-subject variance was explained by subjective health. A one-step decrease in health was associated with a 26 min increase in sleep length. The results have practical implications for constructing shift schedules. Early morning shifts reduced sleep length substantially and should be mixed with later start hours to avoid the accumulation of sleep dept. Delaying the shift-start past 10:00 h had little effect on sleep opportunity; however, delaying shift-start to between 04:30 and 9:00 h had a strong impact on sleep length, with 70% of the extra time used for sleep, suggesting large positive effects for this range of shift-start times.
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| 21. |
- Ingre, Michael, et al.
(författare)
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Validating and Extending the Three Process Model of Alertness in Airline Operations.
- 2014
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 9:10, s. e108679-
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Tidskriftsartikel (refereegranskat)abstract
- Sleepiness and fatigue are important risk factors in the transport sector and bio-mathematical sleepiness, sleep and fatigue modeling is increasingly becoming a valuable tool for assessing safety of work schedules and rosters in Fatigue Risk Management Systems (FRMS). The present study sought to validate the inner workings of one such model, Three Process Model (TPM), on aircrews and extend the model with functions to model jetlag and to directly assess the risk of any sleepiness level in any shift schedule or roster with and without knowledge of sleep timings. We collected sleep and sleepiness data from 136 aircrews in a real life situation by means of an application running on a handheld touch screen computer device (iPhone, iPod or iPad) and used the TPM to predict sleepiness with varying level of complexity of model equations and data. The results based on multilevel linear and non-linear mixed effects models showed that the TPM predictions correlated with observed ratings of sleepiness, but explorative analyses suggest that the default model can be improved and reduced to include only two-processes (S+C), with adjusted phases of the circadian process based on a single question of circadian type. We also extended the model with a function to model jetlag acclimatization and with estimates of individual differences including reference limits accounting for 50%, 75% and 90% of the population as well as functions for predicting the probability of any level of sleepiness for ecological assessment of absolute and relative risk of sleepiness in shift systems for safety applications.
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| 22. |
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| 23. |
- Ingre, Michael
(författare)
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Why small low-powered studies are worse than large high-powered studies and how to protect against "trivial" findings in research : comment on Friston (2012)
- 2013
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Ingår i: NeuroImage. - : Elsevier BV. - 1053-8119 .- 1095-9572. ; 81, s. 496-498
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- It is sometimes argued that small studies provide better evidence for reported effects because they are less likely to report findings with small and trivial effect sizes (Friston, 2012). But larger studies are actually better at protecting against inferences from trivial effect sizes, if researchers just make use of effect sizes and confidence intervals. Poor statistical power also comes at a cost of inflated proportion of false positive findings, less power to "confirm" true effects and bias in reported (inflated) effect sizes. Small studies (n=16) lack the precision to reliably distinguish small and medium to large effect sizes (r<.50) from random noise (α=.05) that larger studies (n=100) does with high level of confidence (r=.50, p=.00000012). The present paper presents the arguments needed for researchers to refute the claim that small low-powered studies have a higher degree of scientific evidence than large high-powered studies.
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| 24. |
- Kamal, Habiba, et al.
(författare)
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Age-specific and sex-specific risks for HCC in African-born persons with chronic hepatitis B without cirrhosis
- 2023
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Ingår i: Hepatology Communications. - : Wolters Kluwer. - 2471-254X. ; 7:12
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Tidskriftsartikel (refereegranskat)abstract
- Background: The international recommendations of HCC surveillance for African-born persons with chronic hepatitis B (CHB) without cirrhosis are divergent, probably due to scarce data on incidence rate (IR) for HCC.Methods: We assembled a cohort with prospectively collected data of Swedish residents of African origin with diagnosed CHB without cirrhosis at baseline from 1990 to 2015. Data from nationwide registers were used to calculate the sex-specific IR and IR ratio (incidence rate ratios) in relation to age, comorbidities, and birth region, using a generalized linear model with a log-link function and Poisson distribution.Results: Among 3865 African-born persons with CHB without cirrhosis at baseline, 31 (0.8%; 77.4% men) developed HCC during a median of 11.1 years of follow-up, with poor survival after HCC diagnosis. The mean age at HCC diagnosis was 46.8 (SD±14.7; range 23–79) in men. HCC IR exceeded the recommended surveillance threshold of 0.2%/year at ages 54 and 59 years in men and women, respectively, and at ages 20–40 years if HCV or HDV co-infection was present. African-born men with CHB had an incidence rate ratios of 10.6 (95% CI 4.4–31.5) for HCC compared to matched African-born peers without CHB, and an incidence rate ratios of 35.3 (95% CI 16.0–88.7) compared to a matched general population.Conclusions: African-born men with CHB without cirrhosis reached an IR of 0.2%/year between 50 and 60 years, and at younger ages if HCV or HDV co-infection was present. Our findings need further confirmation, and new cost-effectiveness analyses specific for young populations are needed, to provide personalized and cost-effective HCC surveillance.
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| 25. |
- Kamal, Habiba, et al.
(författare)
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Age-specific and sex-specific risks for HCC in African-born persons with chronic hepatitis B without cirrhosis
- 2023
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Ingår i: Hepatology communications. - : Wiley Periodicals Inc. on behalf of the American Association for the Study of Liver Diseases. - 2471-254X. ; 7:12
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The international recommendations of HCC surveillance for African-born persons with chronic hepatitis B (CHB) without cirrhosis are divergent, probably due to scarce data on incidence rate (IR) for HCC.METHODS: We assembled a cohort with prospectively collected data of Swedish residents of African origin with diagnosed CHB without cirrhosis at baseline from 1990 to 2015. Data from nationwide registers were used to calculate the sex-specific IR and IR ratio (incidence rate ratios) in relation to age, comorbidities, and birth region, using a generalized linear model with a log-link function and Poisson distribution.RESULTS: Among 3865 African-born persons with CHB without cirrhosis at baseline, 31 (0.8%; 77.4% men) developed HCC during a median of 11.1 years of follow-up, with poor survival after HCC diagnosis. The mean age at HCC diagnosis was 46.8 (SD±14.7; range 23-79) in men. HCC IR exceeded the recommended surveillance threshold of 0.2%/year at ages 54 and 59 years in men and women, respectively, and at ages 20-40 years if HCV or HDV co-infection was present. African-born men with CHB had an incidence rate ratios of 10.6 (95% CI 4.4-31.5) for HCC compared to matched African-born peers without CHB, and an incidence rate ratios of 35.3 (95% CI 16.0-88.7) compared to a matched general population.CONCLUSIONS: African-born men with CHB without cirrhosis reached an IR of 0.2%/year between 50 and 60 years, and at younger ages if HCV or HDV co-infection was present. Our findings need further confirmation, and new cost-effectiveness analyses specific for young populations are needed, to provide personalized and cost-effective HCC surveillance.
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