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  • 105351.
    Åkermark, Björn
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Sjögren, Magnus P.T.
    Iron-catalyzed nucleophilic substitution of allylic acetate2007In: Advanced Synthesis & Catalysis, ISSN 1615-4150, Vol. 349, no 17-18, p. 2641-2646Article in journal (Refereed)
  • 105352.
    Åkerstedt, Caroline
    Stockholm University, Faculty of Social Sciences, School of Business.
    The Need for an Applied Ethics of Representation in Corporate Social Responsibility2003Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Explores what ethical tools are offered by the research field of Corporate Social Responsibility to handle the ethical issues in the criticism towards Swedish design put forward by Rampell (2002). Perceives the core ethical problem in the research conducted by Rampell (2002) to be the exclusion of minority groups in Swedish design. Looks at the context in which Swedish design developed and how it is described at commercial and official public web sites mainly directed at tourists and foreigners. The examination shows that the distinguishing features that represents the image of Swedish design that Rampell (2002) points out and criticizes still prevails; even though Sweden today is a multicultural country, a single-track image of Swedish design is transmitted to the world. Creates a test case; Swedish design, i.e. an issue at the intersection of the political, cultural and economical systems. Thus, CSR should apply. Reviews CSR and its relation to Business Ethics. Examines what is being discussed in the Nordic CSR context by investigating 19 out of the 20 papers put forward at the CSR track at the Scandinavian management conference NFF2003 that was carried out 14th-16th of August 2003 in Reykjavik, Iceland. Suggests how general CSR theory and the conference development of CSR could apply to the test case, Swedish design. Suggests what is needed are tools to handle the visual semantic based meanings in the Swedish design case, i.e. an applied ethics of representation.

  • 105353.
    Åkerstedt, Henrik
    et al.
    Stockholm University, Faculty of Science, Department of Physics.
    Bohm, Christian
    Stockholm University, Faculty of Science, Department of Physics.
    Muschter, Steffen
    Stockholm University, Faculty of Science, Department of Physics.
    Silverstein, Samuel B.
    Stockholm University, Faculty of Science, Department of Physics.
    Valdés, Eduardo
    Stockholm University, Faculty of Science, Department of Physics.
    A radiation tolerant Data link board for the ATLAS Tile Cal upgrade2016In: Journal of Instrumentation, ISSN 1748-0221, E-ISSN 1748-0221, Vol. 11, article id C01074Article in journal (Refereed)
    Abstract [en]

    This paper describes the latest, full-functionality revision of the high-speed data link board developed for the Phase-2 upgrade of ATLAS hadronic Tile Calorimeter. The link board design is highly redundant, with digital functionality implemented in two Xilinx Kintex-7 FPGAs, and two Molex QSFP+ electro-optic modules with uplinks run at 10 Gbps. The FPGAs are remotely configured through two radiation-hard CERN GBTx deserialisers (GBTx), which also provide the LHC-synchronous system clock. The redundant design eliminates virtually all single-point error modes, and a combination of triple-mode redundancy (TMR), internal and external scrubbing will provide adequate protection against radiation-induced errors. The small portion of the FPGA design that cannot be protected by TMR will be the dominant source of radiation-induced errors, even if that area is small.

  • 105354.
    Åkerstedt, Henrik
    et al.
    Stockholm University, Faculty of Science, Department of Physics.
    Muschter, Steffen
    Stockholm University, Faculty of Science, Department of Physics.
    Drake, Gary
    Anderson, Kelby
    Bohm, Christian
    Stockholm University, Faculty of Science, Department of Physics.
    Oreglia, Mark
    Tang, Fukun
    Reliable and Redundant FPGA Based Read-Out Design in the ATLAS TileCal Demonstrator2015In: IEEE Transactions on Nuclear Science, ISSN 0018-9499, E-ISSN 1558-1578, Vol. 62, no 5, p. 2129-2133Article in journal (Refereed)
    Abstract [en]

    The current ATLAS Tile Calorimeter read-out system is scheduled for replacement around 2023 due to old age and higher performance needs. The new proposed system is designed to be radiation tolerant, modular, redundant and reconfigurable. To achieve full detector read-out, Kintex-7 FPGAs from Xilinx will be used, in addition to multiple 10 Gb/s optical read-out links. During 2015/2016, a hybrid demonstrator system including the new read-out system will be installed in one slice of the ATLAS Tile Calorimeter to evaluate the new design. This paper describes different firmware strategies along with their integration in the demonstrator in the context of high reliability protection against hardware malfunction and radiation induced errors.

  • 105355. Åkerstedt Lindell, Gunlög
    Retorik och demokrati2009In: Förskoletidningen, ISSN 1402-7135, Vol. 34, no 5, p. 18-23Article in journal (Other (popular science, discussion, etc.))
  • 105356.
    Åkerstedt Lindell, Gunlög
    Stockholm University, Faculty of Humanities, Department of Swedish Language and Multilingualism, Scandinavian Languages.
    Retoriklek i förskolan2014 (ed. 1)Book (Other academic)
    Abstract [sv]

    Hur kan du som pedagog arbeta med retorik redan i förskolan? Den här boken ger dig både teori och förslag på konkreta aktiviteter som stimulerar till självkänsla, samarbete, tala, berätta och lyssna.

    Fokus i boken är lagd på att barnen ska utveckla ett rikt språkbruk, argumentera och lösa konflikter och träna samarbete och turtagning. Boken bjuder också på utvecklande retorikövningar för arbetslaget. Till materialet hör en lärarwebb med filmer som kompletterar boken.

  • 105357. Åkerstedt Lindell, Gunlög
    Språket ger makt2009In: Förskoletidningen, ISSN 1402-7135, Vol. 34, no 5, p. 26-34Article in journal (Other (popular science, discussion, etc.))
  • 105358.
    Åkerstedt Lindell, Gunlög
    et al.
    Stockholm University, Faculty of Humanities, Department of Swedish Language and Multilingualism, Scandinavian Languages.
    Rönnlid, Pernilla
    Lära för livet2013In: Lära Stockholm: inspiration och information från utbildningsförvaltningen i Stockholms stad, ISSN 1654-7330, no 2, p. 24-27Article in journal (Other (popular science, discussion, etc.))
  • 105359. Åkerstedt Miley, Anna
    et al.
    Kecklund, Göran
    Stockholm University, Faculty of Social Sciences, Stress Research Institute. Karolinska Institute, Sweden.
    Åkerstedt, Torbjörn
    Stockholm University, Faculty of Social Sciences, Stress Research Institute. Karolinska Institute, Sweden.
    Comparing two versions of the Karolinska Sleepiness Scale (KSS)2016In: Sleep and Biological Rhythms, ISSN 1446-9235, E-ISSN 1479-8425, Vol. 14, no 3, p. 257-260Article in journal (Refereed)
    Abstract [en]

    The Karolinska Sleepiness Scale (KSS) is frequently used to study sleepiness in various contexts. However, it exists in two versions, one with labels on every other step (version A), and one with labels on every step (version B) on the 9-point scale. To date, there are no studies examining whether these versions can be used interchangeably. The two versions were here compared in a 24 hr wakefulness study of 12 adults. KSS ratings were obtained every hour, alternating version A and B. Results indicated that the two versions are highly correlated, do not have different response distributions on labeled and unlabeled steps, and that the distributions across all steps have a high level of correspondence (Kappa = 0.73). It was concluded that the two versions are quite similar.

  • 105360.
    Åkerstedt, Olof
    Stockholm University, Faculty of Humanities, Department of Spanish, Portuguese and Latin American Studies.
    Figuras retóricas en el hip-hop español2013Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The present study is a delving in the rhetoric of Spanish hip hop with focus on five songs of some of the most prominent artists in the genre in Spain. The aim is a study of the rhetorical figures present in these songs and which function they have in the context of the songs and of hip-hop. The analysis is based on previous studies in the same field as well as different dictionaries and handbooks of rhetorical figures but many conclusions also derive from the investigators own interpretations . The underlying purpose of this study is to locate tendencies in the rhetorical expression used in these songs; the result will be a suggestion of what possibly could be representative for this genre in Spain.

     

  • 105361.
    Åkerstedt, Torbjorn
    et al.
    Stockholm University, Faculty of Social Sciences, Stress Research Institute. Karolinska Institute, Sweden.
    Schwarz, Johanna
    Stockholm University, Faculty of Social Sciences, Stress Research Institute. Karolinska Institute, Sweden.
    Gruber, Georg
    Theorell-Haglöw, Jenny
    Lindberg, Eva
    Short sleep-poor sleep? A polysomnographic study in a large population-based sample of women2019In: Journal of Sleep Research, ISSN 0962-1105, E-ISSN 1365-2869, Vol. 28, no 4, article id e12812Article in journal (Refereed)
    Abstract [en]

    There is a lack of studies on the association between total sleep time (TST) and other polysomnographical parameters. A key question is whether a short sleep is an expression of habitual short sleep, or whether it reflects temporary impairment. The purpose of the present study was to investigate the association between TST and amount of sleep stages and sleep continuity measures, in a large population-based sample of women (n = 385), sleeping at home in a normal daily life setting. The results show that sleep efficiency, N1 (min), N2 (min), REM (min), REM% and proportion of long sleep segments, increased with increasing TST, whereas the number of awakenings/hr, the number of arousals/hr, N1% and REM intensity decreased. In addition, longer sleep was more associated with TST being perceived as of usual duration and with better subjective sleep quality. TST was not associated with habitual reported sleep duration. It was concluded that short TST of a recorded sleep in a real-life context may be an indicator of poor objective sleep quality for that particular sleep episode. Because individuals clearly perceived this reduction, it appears that self-reports of poor sleep quality often may be seen as indicators of poor sleep quality. It is also concluded that PSG-recorded sleep duration does not reflect habitual reported sleep duration in the present real-life context.

  • 105362. Åkerstedt, Torbjörn
    Altered sleep/wake patterns and circadian rhythms: laboratory and field studies of sympathoadrenomedullary and related variables1979Doctoral thesis, comprehensive summary (Other academic)
  • 105363.
    Åkerstedt, Torbjörn
    Stockholm University, Faculty of Social Sciences, Stress Research Institute.
    Arbete som stör dygnsrytmen2008In: Arbetslivsfysiologi, Studentlitteratur, Lund , 2008, p. 279-306Chapter in book (Other (popular science, discussion, etc.))
  • 105364.
    Åkerstedt, Torbjörn
    Stockholm University, Faculty of Social Sciences, Stress Research Institute.
    Occupational Impact2013In: Encyclopedia of Sleep / [ed] Clete Kushida, Academic Press, 2013, p. 308-310Chapter in book (Refereed)
    Abstract [en]

    Occupational impact on sleep is mostly associated with psychosocial factors. In particular, high work demands (stress) lead to increased activation, which causes difficulties initiating or maintaining sleep. At severe levels, characterized by preoccupation with the work situation, sleep is strongly affected and may in the long run lead to burnout, with very poor sleep (far beyond that of the insomniac) and extreme exhaustion. Physical work factors seem to have only marginal effects on sleep.

  • 105365.
    Åkerstedt, Torbjörn
    Stockholm University, Faculty of Social Sciences, Stress Research Institute.
    Sleep and recovery2009In: research in occupational stress and well being, ISSN 1479-3555, Vol. 7, p. 205-247Article, review/survey (Other academic)
    Abstract [en]

    This chapter summarizes the knowledge of sleep and restitution.

  • 105366.
    Åkerstedt, Torbjörn
    Stockholm University, Faculty of Social Sciences, Stress Research Institute.
    Social and Economic Impact2013In: Encyclopedia of Sleep / [ed] Clete Kushida, Academic Press, 2013, p. 306-307Chapter in book (Refereed)
    Abstract [en]

    Social factors influence sleep. Socioeconomic status (SES) may be the most important factor, with longer and better sleep among higher SES groups. The reasons may be related to income, education, healthier lifestyles and several other issues. Social support is a strong predictor of good sleep. Also race is related to sleep, with better sleep among whites. SES is of importance here, but unfair treatment is also important. Sleep also deteriorates with increasing age, but alertness increases. Women report more sleep problems than men but sleep is physiologically better. Singles in general show more sleep complaints, which may be related to unhealthy lifestyles and to some extent to social isolation.

  • 105367.
    Åkerstedt, Torbjörn
    Stockholm University, Faculty of Social Sciences, Stress Research Institute.
    Sömn och sömnreglering - mekanismer bakom sömnens uttryck utanför patologin2010Conference paper (Other academic)
  • 105368.
    Åkerstedt, Torbjörn
    Stockholm University, Faculty of Social Sciences, Stress Research Institute.
    Sömnen2012In: Hjärnan / [ed] Lars Olson och Anna Josephson, Solna: Karolinska Institutet University Press , 2012, 2, p. 145-161Chapter in book (Refereed)
  • 105369.
    Åkerstedt, Torbjörn
    Stockholm University, Faculty of Social Sciences, Stress Research Institute.
    Återhämtning och sömn2012In: Psykosocial miljö och stress / [ed] Töres Theorell, Lund: Studentlitteratur AB, 2012, 2, p. 81-90Chapter in book (Other academic)
  • 105370.
    Åkerstedt, Torbjörn
    et al.
    Stockholm University, Faculty of Social Sciences, Stress Research Institute.
    Alfredsson, L
    Westerholm, P
    Fischer, H
    Nilsson, L-G
    Nordin, M
    Fatigue/sleepiness and important aspects of sleep restoration improve across aging2014Conference paper (Other academic)
  • 105371.
    Åkerstedt, Torbjörn
    et al.
    Stockholm University, Faculty of Social Sciences, Stress Research Institute. Karolinska Institutet.
    Anund, Anna
    Axelsson, John
    Kecklund, Göran
    Stockholm University, Faculty of Social Sciences, Stress Research Institute.
    Subjective sleepiness is a sensitive indicator of insufficient sleep and impaired waking function2014In: Journal of Sleep Research, ISSN 0962-1105, E-ISSN 1365-2869, Vol. 23, no 3, p. 240-252Article in journal (Refereed)
    Abstract [en]

    The main consequence of insufficient sleep is sleepiness. While measures of sleep latency, continuous encephalographical/electro-oculographical (EEG/EOG) recording and performance tests are useful indicators of sleepiness in the laboratory and clinic, they are not easily implemented in large, real-life field studies. Subjective ratings of sleepiness, which are easily applied and unobtrusive, are an alternative, but whether they measure sleepiness sensitively, reliably and validly remains uncertain. This review brings together research relevant to these issues. It is focused on the Karolinska Sleepiness Scale (KSS), which is a nine-point Likert-type scale. The diurnal pattern of sleepiness is U-shaped, with high KSS values in the morning and late evening, and with great stability across years. KSS values increase sensitively during acute total and repeated partial sleep deprivation and night work, including night driving. The effect sizes range between 1.5 and 3. The relation to driving performance or EEG/EOG indicators of sleepiness is highly significant, strongly curvilinear and consistent across individuals. High (>6) KSS values are associated particularly with impaired driving performance and sleep intrusions in the EEG. KSS values are also increased in many clinical conditions such as sleep apnea, depression and burnout. The context has a strong influence on KSS ratings. Thus, physical activity, social interaction and light exposure will reduce KSS values by 1-2 units. In contrast, time-on-task in a monotonous context will increase KSS values by 1-2 units. In summary, subjective ratings of sleepiness as described here is as sensitive and valid an indicator of sleepiness as objective measures, and particularly suitable for field studies.

  • 105372.
    Åkerstedt, Torbjörn
    et al.
    Stockholm University, Faculty of Social Sciences, Stress Research Institute.
    Axelsson, John
    Stockholm University, Faculty of Social Sciences, Stress Research Institute.
    Kecklund, Göran
    Stockholm University, Faculty of Social Sciences, Stress Research Institute.
    Individual validation of model predictions of sleepiness and sleep hours2007In: Somnologie, Vol. 11, p. 169-174Article in journal (Other (popular science, discussion, etc.))
    Abstract [sv]

    Several mathematical models for prediction of sleepiness have been developed. Few validations on individual levels are available.

    Background

    The present study was designed to provide validation on the individual level of predictions using the Three Process-Model of alertness regulation. Model predictions of sleep timing were also tested.

    Method

    Sixteen shift workers participated in the study. Ratings of sleepiness were made every 2h across three shifts. The model was used to predict empirical ratings using as input only information of beginning and end of work shifts, as well as using information on sleep from actigraphs (in a separate analysis).

    Results

    The prediction using only information on work shifts correlated r=0.55 (p<0.001) with empirical ratings. Predictions were generally within ±1 confidence interval of the ratings. Adding actigraphy sleep data improved predictions marginally. The model predictions of onset and offset of sleep were generally close to the target.

    Conclusion

    It was concluded that model predictions have a rather high validity both with respect to sleepiness and to sleep timing. It is probable that other information on individual differences will further improve predictability.

  • 105373.
    Åkerstedt, Torbjörn
    et al.
    Stockholm University, Faculty of Social Sciences, Stress Research Institute.
    Axelsson, John
    Lekander, Mats
    Stockholm University, Faculty of Social Sciences, Stress Research Institute.
    Orsini, Nicola
    Kecklund, Göran
    Stockholm University, Faculty of Social Sciences, Stress Research Institute.
    Do sleep, stress, and illness explain daily variations in fatigue?: A prospective study2014In: Journal of Psychosomatic Research, ISSN 0022-3999, E-ISSN 1879-1360, Vol. 76, no 4, p. 280-285Article in journal (Refereed)
    Abstract [en]

    Objective: Fatigue is related to a number of serious diseases, as well as to general well-being. It is also a major cause of sickness absence and use of health facilities. Still, the determinants of variations in fatigue are little investigated. The purpose of present study was to investigate the relationships between the daily variations of fatigue with sleep during the previous night, stress or disease symptoms during the same day - across 42 consecutive days of normal life. Methods: 50 individuals participated and gave diary reports and used an actigraph across the 42 days. The data was analyzed using a multilevel approach with mixed model regression. Results: The analyses showed that the day-to-day variation in fatigue was related to (poor) sleep quality (p < .001) and (reduced) sleep duration (p < .01) the previous night, as well as to higher stress (p < .05), and to the occurrence of a cold or fever (p < .001) during the same day as the fatigue rating. Fatigue was also strongly related to poorer subjective health (p < .001) and sleepiness (p < .001) during the same day. Conclusion: The results indicate that prior sleep (and sleepiness) as well as stress and illness are consistently connected to how fatigue is experienced during normal living conditions.

  • 105374.
    Åkerstedt, Torbjörn
    et al.
    Stockholm University, Faculty of Social Sciences, Stress Research Institute.
    Axelsson, John
    Lekander, Mats
    Stockholm University, Faculty of Social Sciences, Stress Research Institute.
    Orsini, Nicola
    Kecklund, Göran
    Stockholm University, Faculty of Social Sciences, Stress Research Institute.
    The daily variation in sleepiness and its relation to the preceding sleep episode - a prospective study across 42days of normal living2013In: Journal of Sleep Research, ISSN 0962-1105, E-ISSN 1365-2869, Vol. 22, no 3, p. 258-265Article in journal (Refereed)
    Abstract [en]

    Sleepiness is linked to accidents and reduced performance, and is usually attributed to short/poor prior sleep and sleepiness. However, while the link between reduced sleep and subsequent sleepiness is well established in laboratory experiments of sleep reduction, very little is known about the day-to-day variation of sleepiness in everyday life and its relation to the immediately preceding sleep episode. The purpose of the present study was to investigate the characteristics of this relation across 42 consecutive days. Fifty volunteers participated. Self-reports of sleep were given in the morning and recorded with actigraphy; health was rated in the evening; and sleepiness was rated at eight points during the day (on a scale of 1-9). Results from mixed-model regression analyses showed that, on average, total sleep time predicted sleepiness during the rest of the day across the 42 days, with sleepiness increasing with shorter preceding sleep (β = -0.15 units h(-1) , P < 0.001). Sleepiness also increased with earlier time of rising and lower-rated sleep quality. Days off reduced sleepiness, but was accounted for by sleep. Self-rated health improved when sleepiness was low during the same day (β = -0.36 unit unit(-1) of rated health, P < 0.001), but the two were measured simultaneously. Napping was related to high sleepiness during the same day. Actigraphy measures of sleep duration showed similar, but somewhat weaker, effects than diary measures. It was concluded that the main determinants of daytime sleepiness in a real-life day-to-day context were short sleep, poor sleep and early rising, and that days with high sleepiness ended with ratings of poorer health.

  • 105375.
    Åkerstedt, Torbjörn
    et al.
    Stockholm University, Faculty of Social Sciences, Stress Research Institute. Karolinska Institute, Sweden.
    Discacciati, Andrea
    Miley-Åkerstedt, Anna
    Westerlund, Hugo
    Stockholm University, Faculty of Social Sciences, Stress Research Institute.
    Aging and the Change in Fatigue and Sleep - A Longitudinal Study Across 8 Years in Three Age Groups2018In: Frontiers in Psychology, ISSN 1664-1078, E-ISSN 1664-1078, Vol. 9, article id 234Article in journal (Refereed)
    Abstract [en]

    Fatigue is prevalent in the population and usually linked to sleep problems, and both are related to age. However, previous studies have been cross-sectional. The purpose of the present study was to investigate the trajectories of sleep and fatigue across 8 years of aging in a large group (N > 8.000) of individuals. A second purpose was to investigate whether fatigue trajectories would differ between age groups, and whether different trajectories of fatigue would be reflected in a corresponding difference in trajectories for sleep variables. Results from mixed model analyses showed that fatigue decreased across 8 years in all age groups, while sleep problems increased, non-restorative sleep decreased, weekend sleep duration decreased, and weekday sleep duration showed different patterns depending on age. Furthermore, the larger the decrease in fatigue, the larger was the increase in sleep duration across years, the lower was the increase of sleep problems, and the larger was the decrease of non-restorative sleep. The results suggest that aging has positive effects on fatigue and sleep and that these changes are linked.

  • 105376.
    Åkerstedt, Torbjörn
    et al.
    Stockholm University, Faculty of Social Sciences, Stress Research Institute. Karolinska Institutet, Sweden.
    Garefelt, Johanna
    Stockholm University, Faculty of Social Sciences, Stress Research Institute.
    Richter, Anne
    Stockholm University, Faculty of Social Sciences, Department of Psychology. Karolinska Institutet, Sweden.
    Westerlund, Hugo
    Stockholm University, Faculty of Social Sciences, Stress Research Institute.
    Magnusson Hanson, Linda L.
    Stockholm University, Faculty of Social Sciences, Stress Research Institute.
    Sverke, Magnus
    Stockholm University, Faculty of Social Sciences, Department of Psychology. North West University, South Africa.
    Kecklund, Göran
    Stockholm University, Faculty of Social Sciences, Stress Research Institute. Karolinska Institutet, Sweden.
    Work and Sleep - A Prospective Study of Psychosocial Work Factors, Physical Work Factors, and Work Scheduling2015In: Sleep, ISSN 0161-8105, E-ISSN 1550-9109, Vol. 38, no 7, p. 1129-1136Article in journal (Refereed)
    Abstract [en]

    Study Objectives: There is limited knowledge about the prospective relationship between major work characteristics (psychosocial, physical, scheduling) and disturbed sleep. The current study sought to provide such knowledge. Design: Prospective cohort, with measurements on two occasions (T1 and T2) separated by two years. Setting: Naturalistic study, Sweden. Participants: There were 4,827 participants forming a representative sample of the working population. Measurements and Results: Questionnaire data on work factors obtained on two occasions were analyzed with structural equation modeling. Competing models were compared in order to investigate temporal relationships. A reciprocal model was found to fit the data best. Sleep disturbances at T2 were predicted by higher work demands at T1 and by lower perceived stress at T1. In addition, sleep disturbances at T1 predicted subsequent higher perception of stress, higher work demands, lower degree of control, and less social support at work at T2. A cross-sectional mediation analysis showed that (higher) perceived stress mediated the relationship between (higher) work demands and sleep disturbances; however, no such association was found longitudinally. Conclusions: Higher work demands predicted disturbed sleep, whereas physical work characteristics, shift work, and overtime did not. In addition, disturbed sleep predicted subsequent higher work demands, perceived stress, less social support, and lower degree of control. The results suggest that remedial interventions against sleep disturbances should focus on psychosocial factors, and that such remedial interventions may improve the psychosocial work situation in the long run.

  • 105377.
    Åkerstedt, Torbjörn
    et al.
    Stockholm University, Faculty of Social Sciences, Stress Research Institute. Karolinska Institutet, Sweden.
    Ghilotti, Francesca
    Grotta, Alessandra
    Stockholm University, Faculty of Social Sciences, Centre for Health Equity Studies (CHESS). Karolinska Institutet, Sweden.
    Bellavia, Andrea
    Trolle Lagerros, Ylva
    Bellocco, Rino
    Sleep duration, mortality and the influence of age2017In: European Journal of Epidemiology, ISSN 0393-2990, E-ISSN 1573-7284, Vol. 32, no 10, p. 881-891Article in journal (Refereed)
    Abstract [en]

    Prior work has shown that both short and long sleep predict mortality. However, sleep duration decreases with age and this may affect the relationship of sleep duration with mortality. The purpose of the present study was to assess whether the association between sleep duration and mortality varies with age. Prospective cohort study. 43,863 individuals (64% women), recruited in September 1997 during the Swedish National March and followed through record-linkages for 13 years. Sleep duration was self-reported and measured using the Karolinska Sleep Questionnaire, and grouped into 4 categories: ae5, 6, 7 (reference) and 8 h. Up to 2010 3548 deaths occurred. Multivariable Cox proportional hazards regression models with attained age as time scale were fitted to estimate mortality rate ratios. Among individuals < 65 years, short (ae5 h) and long (8 h) sleep duration showed a significant relationship with mortality (HR 1.37, 95% CI 1.09-1.71, and HR 1.27, 95% CI 1.08-1.48). Among individuals 65 years or older, no relationships between sleep duration and mortality were observed. The effect of short and long sleep duration on mortality was highest among young individuals and decreased with increasing age. The results suggest that age plays an important role in the relationship between sleep duration and mortality.

  • 105378.
    Åkerstedt, Torbjörn
    et al.
    Stockholm University, Faculty of Social Sciences, Stress Research Institute. Karolinska Institutet, Sweden.
    Ghilotti, Francesca
    Grotta, Alessandra
    Stockholm University, Faculty of Social Sciences, Centre for Health Equity Studies (CHESS). Karolinska Institutet, Sweden.
    Zhao, Hongwei
    Adami, Hans-Olov
    Trolle-Lagerros, Ylva
    Bellocco, Rino
    Sleep duration and mortality - Does weekend sleep matter?2019In: Journal of Sleep Research, ISSN 0962-1105, E-ISSN 1365-2869, Vol. 28, no 1, article id e12712Article in journal (Refereed)
    Abstract [en]

    Previous studies have found a U-shaped relationship between mortality and (weekday) sleep duration. We here address the association of both weekday and weekend sleep duration with overall mortality. A cohort of 43,880 subjects was followed for 13 years through record-linkages. Cox proportional hazards regression models with attained age as time-scale were fitted to estimate multivariable-adjusted hazard ratios and 95% confidence intervals for mortality; stratified analyses on age (<65 years, >= 65 years) were conducted. Among individuals <65 years old, short sleep (<= 5 hr) during weekends at baseline was associated with a 52% higher mortality rate (hazard ratios 1.52; 95% confidence intervals 1.15-2.02) compared with the reference group (7 hr), while no association was observed for long (>= 9 hr) weekend sleep. When, instead, different combinations of weekday and weekend sleep durations were analysed, we observed a detrimental association with consistently sleeping <= 5 hr (hazard ratios 1.65; 95% confidence intervals 1.22-2.23) or >= 8 hr (hazard ratios 1.25; 95% confidence intervals 1.05-1.50), compared with consistently sleeping 6-7 hr per day (reference). The mortality rate among participants with short sleep during weekdays, but long sleep during weekends, did not differ from the rate of the reference group. Among individuals >= 65 years old, no association between weekend sleep or weekday/weekend sleep durations and mortality was observed. In conclusion, short, but not long, weekend sleep was associated with an increased mortality in subjects <65 years. In the same age group, short sleep (or long sleep) on both weekdays and weekend showed increased mortality. Possibly, long weekend sleep may compensate for short weekday sleep.

  • 105379.
    Åkerstedt, Torbjörn
    et al.
    Stockholm University, Faculty of Social Sciences, Stress Research Institute. Karolinska Institute, Sweden.
    Hallvig, David
    Stockholm University, Faculty of Social Sciences, Stress Research Institute.
    Kecklund, Göran
    Stockholm University, Faculty of Social Sciences, Stress Research Institute. Karolinska Institute, Sweden.
    Normative data on the diurnal pattern of the Karolinska Sleepiness Scale ratings and its relation to age, sex, work, stress, sleep quality and sickness absence/illness in a large sample of daytime workers2017In: Journal of Sleep Research, ISSN 0962-1105, E-ISSN 1365-2869, Vol. 26, no 5, p. 559-566Article in journal (Refereed)
    Abstract [en]

    Self-rated sleepiness responds to sleep loss, time of day and work schedules. There is, however, a lack of a normative reference showing the diurnal pattern during a normal working day, compared with a day off, as well as differences depending on stress, sleep quality, sex, age and being sick listed. The present study sought to provide such data for the Karolinska Sleepiness Scale. Participants were 431 individuals working in medium-sized public service units. Sleepiness (Karolinska Sleepiness Scale, scale 1-9) was rated at six times a day for a working week and 2 days off (>90.000 ratings). The results show a clear circadian pattern, with high values during the morning (4.5 at 07:00 hours) and evening (6.0 at 22:00 hours), and with low values (3-4) during the 10:0016: 00 hours span. Women had significantly higher (0.5 units) Karolinska Sleepiness Scale values than men, as did younger individuals (0.3 units), those with stress (1.3 units above the low-stress group) and those with poor sleep quality (1.0 units above those with qood sleep quality). Days off showed reduced sleepiness (0.7 units), while being sick listed was associated with an increased sleepiness (0.8 units). Multiple regression analysis of mean sleepiness during the working week yielded mean daytime stress, mean sleep quality, age, and sex as predictors (not sleep duration). Improved sleep quality accounted for the reduced sleepiness during days off, but reduced stress was a second factor. Similar results were obtained in a longitudinal mixed-model regression analysis across the 7 days of the week. The percentage of ratings at Karolinska Sleepiness Scale risk levels (8 + 9) was 6.6%, but most of these were obtained at 22:00 hours. It was concluded that sleepiness ratings are strongly associated with time of day, sleep quality, stress, work day/day off, being ill, age, and sex.

  • 105380.
    Åkerstedt, Torbjörn
    et al.
    Stockholm University, Faculty of Social Sciences, Stress Research Institute.
    Ingre, Michael
    Stockholm University, Faculty of Social Sciences, Stress Research Institute.
    Kecklund, Göran
    Stockholm University, Faculty of Social Sciences, Stress Research Institute.
    Anund, Anna
    Sandberg, David
    Wahde, Mattias
    Philip, Pierre
    Kronberg, Peter
    Reaction of sleepiness indicators to partial sleep deprivation, time of day and time on task in a driving simulator - the DROWSI project2010In: Journal of Sleep Research, ISSN 0962-1105, E-ISSN 1365-2869, Vol. 19, no 2, p. 298-309Article in journal (Refereed)
    Abstract [en]

    Studies of driving and sleepiness indicators have mainly focused on prior sleep reduction. The present study sought to identify sleepiness indicators responsive to several potential regulators of sleepiness: sleep loss, time of day (TOD) and time on task (TOT) during simulator driving. Thirteen subjects drove a high-fidelity moving base simulator in six 1-h sessions across a 24-h period, after normal sleep duration (8 h) and after partial sleep deprivation (PSD; 4 h). The results showed clear main effects of TOD (night) and TOT but not for PSD, although the latter strongly interacted with TOD. The most sensitive variable was subjective sleepiness, the standard deviation of lateral position (SDLAT) and measures of eye closure [duration, speed (slow), amplitude (low)]. Measures of electroencephalography and line crossings (LCs) showed only modest responses. For most variables individual differences vastly exceeded those of the fixed effects, except for subjective sleepiness and SDLAT. In a multiple regression analysis, SDLAT, amplitude/peak eye-lid closing velocity and blink duration predicted subjective sleepiness bouts with a sensitivity and specificity of about 70%, but were mutually redundant. The prediction of LCs gave considerably weaker, but similar results. In summary, SDLAT and eye closure variables could be candidates for use in sleepiness-monitoring devices. However, individual differences are considerable and there is need for research on how to identify and predict individual differences in susceptibility to sleepiness.

  • 105381.
    Åkerstedt, Torbjörn
    et al.
    Stockholm University, Faculty of Social Sciences, Stress Research Institute.
    Kecklund, Göran
    Stockholm University, Faculty of Social Sciences, Stress Research Institute.
    Sleep, Work, and Occupational Stress2012In: The Oxford Handbook of Sleep and Sleep disorders / [ed] Charles M. Morin, Colin Espie, New York: Oxford University Press , 2012, p. 248-265Chapter in book (Refereed)
  • 105382.
    Åkerstedt, Torbjörn
    et al.
    Stockholm University, Faculty of Social Sciences, Stress Research Institute.
    Kecklund, Göran
    Stockholm University, Faculty of Social Sciences, Stress Research Institute.
    Säkerhet, arbetstider och trötthet2013In: Patientsäkerhet: teori och praktik / [ed] Synnöve Ödegård, Stockholm: Liber, 2013Chapter in book (Other academic)
  • 105383.
    Åkerstedt, Torbjörn
    et al.
    Stockholm University, Faculty of Social Sciences, Stress Research Institute. Karolinska Institute, Sweden.
    Kecklund, Göran
    Stockholm University, Faculty of Social Sciences, Stress Research Institute. Karolinska Institute, Sweden.
    What work schedule characteristics constitute a problem to the individual? A representative study of Swedish shift workers2017In: Applied Ergonomics, ISSN 0003-6870, E-ISSN 1872-9126, Vol. 59, p. 320-325Article in journal (Refereed)
    Abstract [en]

    The purpose was to investigate which detailed characteristics of shift schedules that are seen as problems to those exposed. A representative national sample of non-day workers (N = 2031) in Sweden was asked whether they had each of a number of particular work schedule characteristics and, if yes, to what extent this constituted a "big problem in life". It was also inquired whether the individual's work schedules had negative consequences for fatigue, sleep and social life. The characteristic with the highest percentage reporting a big problem was "short notice (<1 month) of a new work schedule" (30.5%), <11 h off between shifts (27.8%), and split duty (>1.5 h break at mid-shift, 27.2%). Overtime (>10 h/week), night work, morning work, day/night shifts showed lower prevalences of being a "big problem". Women indicated more problems in general. Short notice was mainly related to negative social effects, while <11 h off between shifts was related to disturbed sleep, fatigue and social difficulties. It was concluded that schedules involving unpredictable working hours (short notice), short daily rest between shifts, and split duty shifts constitute big problems. The results challenge current views of what aspects of shift work need improvement, and negative social consequences seem more important than those related to health.

  • 105384.
    Åkerstedt, Torbjörn
    et al.
    Stockholm University, Faculty of Social Sciences, Stress Research Institute.
    Kecklund, Göran
    Stockholm University, Faculty of Social Sciences, Stress Research Institute.
    Axelsson, John
    Impaired sleep after bedtime stress and worries.2007In: Biol Psychol, ISSN 0301-0511, Vol. 76, no 3, p. 170-3Article in journal (Other academic)
    Abstract [en]

    Akerstedt T, Kecklund G, Axelsson J.

    torbjorn.akerstedt@stressforskning.su.se

    Stress is assumed to impair sleep, but there is very little empirical evidence for this using sleep recordings. Here, we recorded sleep (at home) in 33 normal participants on three nights, which followed days with low, high and intermediate stress. The participants made daily ratings of the level of stress/worries at bedtime and also two-hourly ratings of stress. Only those 16 individuals who differed in stress/worries between two nights were analysed. There was a significantly lower sleep efficiency (81.0% versus 85.2%) a higher percent Wake (22.6% versus 15.6%) and a longer latency to Stage 3 (33.9 versus 18.3 min) during the nights with a higher stress/worry bedtime rating. None of the other sleep variables were affected. Also mean daytime stress ratings were significantly higher on the day preceding and following the high stress/worries sleep. It was concluded that moderate increases in stress/worries at bedtime are associated with moderately impaired sleep.

    PMID: 17884278 [PubMed - in process]

  • 105385.
    Åkerstedt, Torbjörn
    et al.
    Stockholm University, Faculty of Social Sciences, Stress Research Institute.
    Kecklund, Göran
    Stockholm University, Faculty of Social Sciences, Stress Research Institute.
    Axelsson, John
    Subjective and objectiv quality of sleep2008In: Somnologie, ISSN 1432-9123, E-ISSN 1439-054X, Vol. 12, p. 104-109Article in journal (Other academic)
    Abstract [en]

    Relatively few studies have tried to relate subjective sleep quality to objective sleep parameters and most have been carried out in laboratory settings and often with patients and usually only for a single night. The present study used a group of 33 subjects who had sleep polysomnographically recorded in their homes for three nights during a period of several weeks. First a multiple regression analysis was carried out for each night with a 4-item sleep quality index as the dependent variable and conventional sleep parameters as predictors. This yielded a significant beta value for percent Stage O for each of the three nights. Sleep efficiency showed a significant correlation with sleep quality for two nights but did not enter the regression. When the night with the best and poorest sleep were compared, the only significant variable became percent SWS. It was suggested that the differing results may have been due to the large age span confusing SWS/quality correlations.

  • 105386.
    Åkerstedt, Torbjörn
    et al.
    Stockholm University, Faculty of Social Sciences, Stress Research Institute.
    Kecklund, Göran
    Stockholm University, Faculty of Social Sciences, Stress Research Institute.
    Selén, Jan
    Disturbed sleep and fatigue as predictors of return from long-term sickness absence2010In: Industrial Health, ISSN 0019-8366, E-ISSN 1880-8026, Vol. 48, no 2, p. 209-14Article in journal (Refereed)
    Abstract [en]

    Long-term sickness absence has doubled in Sweden, as has complaints of disturbed sleep. The present study sought to investigate the prospective link between long-term sickness absence and disturbed sleep or fatigue. Sleep and fatigue from a representative national sample was followed up 1.5-2 yr later in terms of return from long-term (>or=90 d) and intermediate term (14-89 d) sickness absence. 8,300 individuals participated in the survey, out of which 372 were on long-term and 1,423 were on intermediate term sick leave. The data was analyzed using logistic regression analysis with adjustment for background and work environment variables. Separate analyses were carried out for disturbed sleep and fatigue since they were correlated. The results showed that those with disturbed sleep at the start had an Odds Ratio (OR) of 0.56 (95% Confidence Interval (CI)=0.35-0.90) for returning from long-term sickness absence. For fatigue the results were OR=0.56 (CI=0.34-0.90). Intermediate term sickness absence showed similar, but slightly weaker, results. The results indicate that disturbed sleep and fatigue are predictors of lack of return from long term and intermediate term sickness absence.

  • 105387.
    Åkerstedt, Torbjörn
    et al.
    Stockholm University, Faculty of Social Sciences, Stress Research Institute.
    Kecklund, Göran
    Stockholm University, Faculty of Social Sciences, Stress Research Institute.
    Selén, Jan
    Early morning work--prevalence and relation to sleep/wake problems: a national representative survey.2010In: Chronobiology International, ISSN 0742-0528, E-ISSN 1525-6073, Vol. 27, no 5, p. 975-86Article in journal (Refereed)
    Abstract [en]

    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.

  • 105388.
    Åkerstedt, Torbjörn
    et al.
    Stockholm University, Faculty of Social Sciences, Stress Research Institute. Karolinska Institutet, Sweden.
    Knutsson, Anders
    Narusyte, Jurgita
    Svedberg, Pia
    Kecklund, Göran
    Stockholm University, Faculty of Social Sciences, Stress Research Institute. Radboud University Nijmegen, Netherlands.
    Alexanderson, Kristina
    Night work and breast cancer in women: a Swedish cohort study2015In: BMJ Open, ISSN 2044-6055, E-ISSN 2044-6055, Vol. 5, no 4, article id e008127Article in journal (Refereed)
    Abstract [en]

    OBJECTIVES: Recent research has suggested a moderate link between night work and breast cancer in women, mainly through case-control studies, but non-significant studies are also common and cohort studies are few. The purpose of the present study was to provide new information from cohort data through investigating the association between the number of years with night work and breast cancer among women.

    DESIGN: Cohort study of individuals exposed to night shift work in relation to incidence of breast cancer in women.

    SETTING: Individuals in the Swedish Twin registry, with follow-up in the Swedish Cancer Registry.

    PARTICIPANTS: 13 656 women from the Swedish Twin Registry, with 3404 exposed to night work.

    OUTCOME MEASURES: Breast cancer from the Swedish Cancer Registry (463 cases) during a follow-up time of 12 years.

    RESULTS: A Cox proportional hazards regression analysis with control for a large number of confounders showed that the HR was HR=1.68 (95% CI 0.98 to 2.88) for the group with >20 years of night work. When the follow-up time was limited to ages below 60 years, those exposed >20 years showed a HR=1.77 (95% CI 1.03 to 3.04). Shorter exposure to night work showed no significant effects.

    CONCLUSIONS: The present results, together with previous work, suggest that night work is associated with an increased risk of breast cancer in women, but only after relatively long-term exposure.

  • 105389.
    Åkerstedt, Torbjörn
    et al.
    Stockholm University, Faculty of Social Sciences, Stress Research Institute. Karolinska Institutet.
    Lekander, Mats
    Stockholm University, Faculty of Social Sciences, Stress Research Institute. Karolinska Institutet.
    Nilsonne, Gustav
    Stockholm University, Faculty of Social Sciences, Stress Research Institute. Karolinska Institutet.
    Fischer, Håkan
    Stockholm University, Faculty of Social Sciences, Department of Psychology, Biological psychology.
    Kecklund, Göran
    Stockholm University, Faculty of Social Sciences, Stress Research Institute.
    d'Onofrio, Paolo
    Stockholm University, Faculty of Social Sciences, Stress Research Institute.
    Gruber, G.
    Schwarz, Johanna
    Stockholm University, Faculty of Social Sciences, Stress Research Institute. Karolinska Institutet.
    Women sleep better and have a stronger response to late night curtailed sleep than men, particularly in older individuals: effects on polysomnographical sleep2016Conference paper (Refereed)
    Abstract [en]

    Objectives: Higher age is associated with poorer sleep and women report more sleep problems than men, despite indications of better physiological sleep. The purpose of the present study was to investigate whether a common daily life sleep problem, late night curtailed sleep, would have different effects depending on gender and age. Methods: 60 healthy individuals (equal groups of gender and age (20–30 and 65–75 years)) participated in an experiment with a full night’s sleep and one night with reduced sleep between 0400 h and 0700 h, in a balanced design. Sleep was recorded through standard polysomnography (PSG) at home. Results: The results showed the expected main effect of sleep loss. Older participants had a lower TST, N3%, sleep efficiency, but more N1%, longer N3 latency, and fewer awakenings. Women had more N3%, more REM%, more N3%, and shorter N3 latency compared with men. The curtailed late night sleep caused a stronger increase in N3%, and more pronounced reductions in REM%, a stronger reduction in N1%, and N3 latency in women than men. In the higher age group the N3% response in men was strongly attenuated compared to that of women. Conclusions: The results show that women, apart form getting more N3% and less N1% even in the normal sleep condition, have a stronger response to late night sleep, particularly in higher age groups.

  • 105390.
    Åkerstedt, Torbjörn
    et al.
    Stockholm University, Faculty of Social Sciences, Stress Research Institute. Karolinska Institutet, Sweden.
    Lekander, Mats
    Stockholm University, Faculty of Social Sciences, Stress Research Institute. Karolinska Institutet, Sweden.
    Nilsonne, Gustav
    Stockholm University, Faculty of Social Sciences, Stress Research Institute. Karolinska Institutet, Sweden.
    Tamm, S.
    d'Onofrio, Paolo
    Stockholm University, Faculty of Social Sciences, Stress Research Institute.
    Kecklund, Göran
    Stockholm University, Faculty of Social Sciences, Stress Research Institute.
    Fischer, Håkan
    Stockholm University, Faculty of Social Sciences, Department of Psychology, Biological psychology.
    Petrovic, P.
    Månsson, Kristoffer N.
    Stockholm University, Faculty of Social Sciences, Department of Psychology, Clinical psychology. Karolinska Institutet, Sweden.
    Gray Matter Volume Correlates Of Sleepiness: A Voxel-based Morphometry Study In Younger And Older Adults2018In: Sleep, ISSN 0161-8105, E-ISSN 1550-9109, Vol. 41, p. A58-A58, article id 0149Article in journal (Other academic)
    Abstract [en]

    Introduction: Sleepiness is prevalent in society, often linked to disturbed sleep, shift work, stress, or diseases. It is also associated with an increased risk of accidents. Sleepiness may be related to brain metabolism and, we hypothesize that it is associated with brain gray matter (GM) volume. The present study investigated the association between sleepiness and GM volume in thalamus and insula, with a special focus on age, since both sleepiness and GM volume change with age.

    Methods: In all, 84 healthy individuals participated in the experiment, of which 46 were in the age range 20–30 years and 38 ranging between 65–75 years. Data was collected in a 3 T scanner during a 5 minute anatomical scan (first in a several sessions in the scanner) in the evening after a full night of sleep. Momentary sleepiness (Karolinska Sleepiness Scale) was rated 7 times during the time in the scanner.

    Results: Results showed that, in older, relative to younger adults, areas within bilateral insular cortex and thalamus GM regions of interest were negatively associated (FWE-corrected) with sleepiness (Z=4.02, p=.015 left insula and Z=4.42, p=.009 for right insula; Z=3.75, p=.020 for left thalamus and Z=4.60, p=.001 for right thalamus). Larger volume was associated with low sleepiness in the older group, but not in the older group. The effect in the insula was mainly present in the mid-anterior parts of the structure.. In addition, after applying a conservative small volume correction including all ROIs simultaneously, age-interaction effects remained significant.

    Conclusion: It was concluded that self-rated momentary sleepiness in a monotonous situation is negatively associated with GM volume in areas within both thalamus and insula in older individuals. The results are in line with notions of thalamus as a driver of arousal and of anterior insula as a structure evaluating the state of the organism. Possibly, a larger GM volume in these structures may be protective against sleepiness in older individuals, a hypothesis that needs confirmation in further studies.

  • 105391.
    Åkerstedt, Torbjörn
    et al.
    Stockholm University, Faculty of Social Sciences, Stress Research Institute. Karolinska Institutet, Sweden.
    Lekander, Mats
    Stockholm University, Faculty of Social Sciences, Stress Research Institute. Karolinska Institutet, Sweden.
    Nilsonne, Gustav
    Stockholm University, Faculty of Social Sciences, Stress Research Institute. Karolinska Institutet, Sweden.
    Tamm, Sandra
    D'onofrio, Paolo
    Stockholm University, Faculty of Social Sciences, Stress Research Institute. Karolinska Institutet, Sweden.
    Kecklund, Göran
    Stockholm University, Faculty of Social Sciences, Stress Research Institute.
    Fischer, Håkan
    Stockholm University, Faculty of Social Sciences, Department of Psychology, Biological psychology.
    Schwarz, Johanna
    Stockholm University, Faculty of Social Sciences, Stress Research Institute. Karolinska Institutet, Sweden.
    Effects of late-night short-sleep on in-home polysomnography: relation to adult age and sex2018In: Journal of Sleep Research, ISSN 0962-1105, E-ISSN 1365-2869, Vol. 27, no 4, article id e12626Article in journal (Refereed)
    Abstract [en]

    Bedtime is frequently delayed by many factors in life, and a homeostatic response to the delay may compensate partly for increased time awake and shortened sleep. Because sleep becomes shorter with age and women complain of disturbed sleep more often than men, age and sex differences in the homeostatic response to a delayed bedtime may modify the homeostatic response. The purpose of the present study was to investigate the effect of late-night short-sleep (3 h with awakening at about 07:00 hours) on in-home recorded sleep in men and women in two age groups (20-30 and 65-75 years). Results (N = 59) showed that late-night short-sleep was associated with an increase in percentage of N3 sleep and a decrease in percentage of rapid eye movement sleep, as well as decreases in several measures of sleep discontinuity and rapid eye movement density. Men showed a smaller decrease in percentage of rapid eye movement sleep than women in response to late-night short-sleep, as did older individuals of both sexes compared with younger. Older men showed a weaker percentage of N3 sleep in response to late-night short-sleep than younger men. In general, men showed a greater percentage of rapid eye movement sleep and a lower percentage of N3 sleep than women, and older individuals showed a lower percentage of N3 sleep than younger. In particular, older men showed very low levels of percentage of N3 sleep. We conclude that older males show less of a homeostatic response to late-night short-sleep. This may be an indication of impaired capacity for recovery in older men. Future studies should investigate if this pattern can be linked to gender-associated differences in morbidity and mortality.

  • 105392.
    Åkerstedt, Torbjörn
    et al.
    Stockholm University, Faculty of Social Sciences, Stress Research Institute.
    Lekander, Mats
    Petersén, Helena
    Stockholm University, Faculty of Social Sciences, Stress Research Institute.
    Kecklund, Göran
    Stockholm University, Faculty of Social Sciences, Stress Research Institute.
    Axelsson, John
    Sleep Polysomnography and Reported Stress across 6 Weeks2014In: Industrial Health, ISSN 0019-8366, E-ISSN 1880-8026, Vol. 52, no 1, p. 36-42Article in journal (Refereed)
    Abstract [en]

    Despite the common notion that stress impairs sleep there is little published data showing that sleep (polysomnography [PSG]) is impaired across several sleep episodes in individuals who complain of daily stress during the same period. The present paper aimed at investigating such a connection. 33 subjects had 3 sleeps recorded with PSG at home across 6 weeks and kept a sleep/wake diary each day, including 3-hourly ratings of stress (scale 1-9). The stress ratings and the conventional PSG parameters were averaged across time. A stepwise multiple regression analysis showed that the best predictors of stress were Stage 1 sleep (beta=0.49), latency to Stage 1 sleep (0.47) (adjusted for anxiety and age). Other sleep continuity variables had significant correlations with stress (reversed) but did not enter the multiple regression analysis. The correlation between stress before the start of the study and PSG data was not significant. It was concluded that moderately increased stress over a longer period of time is related to moderate signs of disturbed sleep during that period. This may be of importance when considering stress as a work environment problem.

  • 105393.
    Åkerstedt, Torbjörn
    et al.
    Stockholm University, Faculty of Social Sciences, Stress Research Institute.
    Lindberg, E
    Gruber, G
    Theorell-Haglöw, J
    Schwarz, Johanna F A
    Stockholm University, Faculty of Social Sciences, Stress Research Institute.
    What does good sleep in terms of macro and microstructure of sleep in women and how does age affect this relation?2014In: Journal of sleep research, Special issue: 22nd Congress of the European Sleep Research Society, 16-20 September 2014, Tallinn, Estonia, 2014Conference paper (Other academic)
  • 105394.
    Åkerstedt, Torbjörn
    et al.
    Stockholm University, Faculty of Social Sciences, Stress Research Institute.
    Lindbäck, G.
    Karolinska institutet, Stockholm.
    Night Shiftwork2007In: The Encyclopedia of Stress, Academic Press, 2007, 2, p. 917-920Chapter in book (Refereed)
  • 105395.
    Åkerstedt, Torbjörn
    et al.
    Stockholm University, Faculty of Social Sciences, Stress Research Institute. Karolinska Institutet, Sweden.
    Narusyte, Jurgita
    Alexanderson, Kristina
    Svedberg, Pia
    Sleep Duration, Mortality, and Heredity-A Prospective Twin Study2017In: Sleep, ISSN 0161-8105, E-ISSN 1550-9109, Vol. 40, no 10, article id zsx135Article in journal (Refereed)
    Abstract [en]

    Introduction

    A number of studies have shown a U-shaped association between sleep duration and mortality. Since sleep duration is partly genetically determined, it seems likely that its association with mortality is also genetically influenced. The purpose of the present study was to investigate the influence on heredity on the association between sleep duration and mortality.

    Methods

    We used a cohort of 14 267 twins from the Swedish Twin Registry.

    Results

    A Cox proportional hazards regression analysis, adjusted for a number of covariates, confirmed a clear U shape with a hazard ratio (HR) = 1.34 and 95% confidence interval (CI) = 1.15-1.57 for a sleep duration of = 6.5 hours and HR = 1.18 (CI = 1.07-1.30) for sleep of = 9.5 hours. Reference value was 7.0 hours. A co-twin analysis of 1942 twins discordant on mortality showed a HR = 2.66 (CI = 1.17-6.04) for long (= 9.5 hours) sleep in monzygotic twins and an HR = 0.66 (CI = 0.20-2.14) for short (< 6.5 hours) sleep. In dizygotic twins, no association was significant. The heritability for mortality was 28% for the whole group, while it was 86% for short sleepers and 42% for long sleepers. Thus, the link with mortality for long sleep appears to be more due to environmental factors than to heredity, while heritability dominates among short sleepers.

    Conclusions

    We found that both long and short sleep were associated with higher total mortality, that the difference in mortality within twin pairs is associated with long sleep, and that short sleep has a higher heritability for mortality, while long sleep is associated with more environmental influences on mortality.

  • 105396.
    Åkerstedt, Torbjörn
    et al.
    Stockholm University, Faculty of Social Sciences, Stress Research Institute. Karolinska Institutet, Sweden.
    Narusyte, Jurgita
    Svedberg, Pia
    Kecklund, Göran
    Stockholm University, Faculty of Social Sciences, Stress Research Institute. Radboud University, The Netherlands .
    Alexanderson, Kristina
    Night work and prostate cancer in men: a Swedish prospective cohort study2017In: BMJ Open, ISSN 2044-6055, E-ISSN 2044-6055, Vol. 7, no 6, article id e015751Article in journal (Refereed)
    Abstract [en]

    Objectives Prostate cancer is the most common cancer and the second leading cause of cancer-related deaths among men, but the contributing factors are unclear. One such may be night work because of the day/night alternation of work and the resulting disturbance of the circadian system. The purpose of the present study was to investigate the prospective relation between number of years with night work and prostate cancer in men.

    Design Cohort study comparing night and day working twins with respect to incident prostate cancer in 12 322 men.

    Setting Individuals in the Swedish Twin Registry.

    Participants 12 322 male twins.

    Outcome measures Prostate cancer diagnoses obtained from the Swedish Cancer Registry with a follow-up time of 12 years, with a total number of cases=454.

    Results Multiple Cox proportional hazard regression analysis, adjusted for a number of covariates, showed no association between ever night work and prostate cancer, nor for duration of night work and prostate cancer. Analysis of twin pairs discordant for prostate cancer (n=332) showed no significant association between night work and prostate cancer.

    Conclusions The results, together with previous studies, suggest that night work does not seem to constitute a risk factor for prostate cancer.

  • 105397.
    Åkerstedt, Torbjörn
    et al.
    Stockholm University, Faculty of Social Sciences, Stress Research Institute. Karolinska Institutet, Sweden.
    Nordin, Maria
    Stockholm University, Faculty of Social Sciences, Stress Research Institute. Umeå University, Sweden.
    Alfredsson, Lars
    Westerholm, Peter
    Kecklund, Göran
    Stockholm University, Faculty of Social Sciences, Stress Research Institute. Karolinska Institutet, Sweden.
    Predicting changes in sleep complaints from baseline values and changes in work demands, work control, and work preoccupation - The WOLF-project2012In: Sleep Medicine, ISSN 1389-9457, E-ISSN 1878-5506, Vol. 13, no 1, p. 73-80Article in journal (Refereed)
    Abstract [en]

    Study objective: Stress as a cause of disturbed sleep is often taken for granted, but the longitudinal evidence is limited. The aim of this study was to evaluate new cases of poor sleep as a function of changes in reported work demands, work control, and work preoccupation. Methods: Longitudinal study of change with measures occurring twice within a 5-year interval during a period when the prevalence of impaired sleep was increasing in Sweden. The sample of companies was taken from northern Sweden (Norrland) and included 3637 individuals from the "WOLF Norrland" longitudinal cohort, collected through company health services. Measurement and results: During the measurement period, 16% of those studied developed new cases of impaired sleep. Logistic regressions adjusted for demographics, work environment factors, and disturbed sleep at T1 period one showed a significant increase in new cases for high work demands and high work preoccupation (OR = 1.37; Ci = 1.09-1.72 and OR = 1.80; CI = 1.42-2.28, respectively). The analysis of change in the predictors showed effects of a change from low to high work demands (OR = 1.39; Ci = 1.00-1.95) on new cases of impaired sleep. Consistent high work demands (high at both points) showed a similar increase (OR = 1.49; Ci = 1.06-2.11) but no effect was seen for reduced demands. Change in work preoccupation yielded stronger effects with OR = 2.47 (1.78-2.47) for increased work preoccupation and OR = 3.79 (2.70-5.31) for consistent high work preoccupation. Also, a reduction in work preoccupation was associated with a reduction in new cases of disturbed sleep. Control at work was not related to sleep. Stratification with respect to gender mainly led to fewer significant results (particularly for women) due to larger confidence intervals. Conclusions: It was concluded that self-reported work preoccupation predicts subsequent impairment of sleep and that increased preoccupation is associated with new cases of impaired sleep. Similar, but weaker, results were obtained for work demands.

  • 105398.
    Åkerstedt, Torbjörn
    et al.
    Stockholm University, Faculty of Social Sciences, Stress Research Institute.
    Nordin, Maria
    Alfredsson, Lars
    Westerholm, Peter
    Kecklund, Göran
    Stockholm University, Faculty of Social Sciences, Stress Research Institute.
    Sleep and sleepiness: impact of entering or leaving shiftwork--a prospective study.2010In: Chronobiology International, ISSN 0742-0528, E-ISSN 1525-6073, Vol. 27, no 5, p. 987-96Article in journal (Refereed)
    Abstract [en]

    Very little is known about the effects on sleep and sleepiness of entering or exiting shiftwork. The present study used a longitudinal database (n = 3637). Participants completed a questionnaire on work hours, sleep, and work environment at the start and end of a 5-yr period. Changes in shift/day work status were related to change in a number of subjective sleep variables using logistic regression analysis. The analyses were adjusted for age, sex, and differences in socioeconomic status, work demands, work control, physical workload, marriage status, and number of children. In comparison with constant day work, entering shiftwork (with or without night shifts) from day work increased the risk of difficulties in falling asleep, and leaving shiftwork reduced this risk (odds ratio [OR] = 2.8 [confidence interval, CI = 1.8-4.5]). Also falling asleep at work showed a consistent pattern; an increased risk of falling asleep for those with shiftwork on both occasions, and for those with night work on both occasions. Also entering night work was associated with a strongly increased risk of falling asleep at work (OR = 2.9 [CI = 1.3-6.7]). These results suggest that entering and leaving shiftwork has a considerable impact on sleep and alertness. However, there is a need for large and more extended longitudinal studies to support our findings.

  • 105399.
    Åkerstedt, Torbjörn
    et al.
    National institute for psychosocial factors and health and Department of Public Health Sciences, Karolinska Institutet.
    Olsson, Birgitta
    Stockholm University, Faculty of Social Sciences, Stockholm Business School, Accounting. Lund Universitet.
    Ingre, Michael
    National institute for psychosocial factors and health and Department of Public Health Sciences, Karolinska Institutet.
    Holmgren Caicedo, Mikael
    Stockholm University, Faculty of Social Sciences, Stockholm Business School, Accounting.
    Kecklund, Göran
    National institute for psychosocial factors and health and Department of Public Health Sciences, Karolinska Institutet.
    A 6-hour working day: effects on well-being2001In: Journal of Human Ergology, ISSN 0300-8134, Vol. 30, no 1/2, p. 197-202Article in journal (Refereed)
    Abstract [en]

    The effect of the total amount of work hours and the benefits of a shortening is frequently debated, but very little data is available. The present study compared a group (N=41) that obtained a 9h reduction of the working week (to a 6h day) with a comparison group (N=22) that retained normal work hours. Both groups were constituted of mainly female health care and day care nursery personnel. The experimental group retained full pay and extra personnel were employed to compensate for loss of hours. Questionnaire data were obtained before and 1 year after the change. The data were analyzed using two-factor ANOVA with the interaction of year*group for social factors, sleep quality, mental fatigue, and heart/respiratory complaints, and attitude to work hours. In all cases the experimental group improved whereas the control group did not change. It was concluded that shortened work hours have clear social effects and moderate effects on well-being.

  • 105400.
    Åkerstedt, Torbjörn
    et al.
    Stockholm University, Faculty of Social Sciences, Stress Research Institute. Karolinska Institutet, Sweden.
    Orsini, Nicola
    Petersen, Helena
    Stockholm University, Faculty of Social Sciences, Stress Research Institute. Karolinska Institutet, Sweden.
    Axelsson, John
    Lekander, Mats
    Stockholm University, Faculty of Social Sciences, Stress Research Institute. Karolinska Institutet, Sweden.
    Kecklund, Göran
    Stockholm University, Faculty of Social Sciences, Stress Research Institute. Karolinska Institutet, Sweden.
    Predicting sleep quality from stress and prior sleep - a study of day-to-day covariation across six weeks2012In: Sleep Medicine, ISSN 1389-9457, E-ISSN 1878-5506, Vol. 13, no 6, p. 674-679Article in journal (Refereed)
    Abstract [en]

    Background/objectives: The connection between stress and sleep is well established in cross-sectional questionnaire studies and in a few prospective studies. Here, the intention was to study the link between stress and sleep on a day-to-day basis across 42 days.

    Methods: Fifty participants kept a sleep/wake diary across 42 days and responded to daily questions on sleep and stress. The results were analyzed with a mixed model approach using stress during the prior day to predict morning ratings of sleep quality.

    Results: The results showed that bedtime stress and worries were the main predictors of sleep quality, but that, also, late awakening, short prior sleep, high quality of prior sleep, and good health the prior day predicted higher sleep quality.

    Conclusions: Stress during the day predicts subsequent sleep quality on a day-to-day basis across 42 days. The observed range of variation in stress/worries was modest, which is why it is suggested that the present data underestimates the impact of stress on subsequent sleep quality.

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