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Month-to-month variation in sleep among healthy, Scandinavian daytime workers

Garde, Anne Helene; Hansen, Åse Marie; Persson, Roger LU ; Österberg, Kai LU ; Ørbæk, Palle; Karlson, Björn LU ; Olsen, Annemarie and Kristiansen, Jesper (2014) In Scandinavian Journal of Clinical & Laboratory Investigation 74(6). p.527-535
Abstract
Background. The overall purpose of the present study was to attain more insight in month-to-month variation of sleep duration and quality in order to improve design and interpretation of, e.g. epidemiological studies using sleep as outcome. Methods. The study design entailed monthly self-reports from 38 (26 women/12 men) daytime workers, who completed the Karolinska Sleep Diary (KSD) once a month during one year. A subgroup (n = 16) also wore actigraphs on one day every month during a year. Self-reports of bedtime, time of awakening, sleep duration, individual sleep characteristics, disturbed sleep index (DSI, 4 items) and awakening index (AWI, 3 items) were analyzed together with actigraphy-derived measures. Hours of daylight were used to... (More)
Background. The overall purpose of the present study was to attain more insight in month-to-month variation of sleep duration and quality in order to improve design and interpretation of, e.g. epidemiological studies using sleep as outcome. Methods. The study design entailed monthly self-reports from 38 (26 women/12 men) daytime workers, who completed the Karolinska Sleep Diary (KSD) once a month during one year. A subgroup (n = 16) also wore actigraphs on one day every month during a year. Self-reports of bedtime, time of awakening, sleep duration, individual sleep characteristics, disturbed sleep index (DSI, 4 items) and awakening index (AWI, 3 items) were analyzed together with actigraphy-derived measures. Hours of daylight were used to test for circa-annual variation in statistical models adjusted for intake of hypnotics and alcohol, gender, age and within-person variability. Results. Hours of daylight were found to be associated to self-reported bedtime (p = 0.032) and DSI (p = 0.030), thereby indicating a circa-annual variation. Bedtime was delayed by 1.8 min (95% CI: 0.6-2.9 min) per 1 hour increase in length of daylight. Sleep was slightly more disturbed during the winter. Conclusion. Only circa-annual variation in self-reports of bedtime and DSI were observed in a healthy daytime working population, and the effects were small. Therefore potential bias due to circa-annuality in the studied parameters appears to be of limited concern in adult daytime working populations. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Sleep quality, circa-annual variation, human, sleep duration
in
Scandinavian Journal of Clinical & Laboratory Investigation
volume
74
issue
6
pages
527 - 535
publisher
Informa Healthcare
external identifiers
  • wos:000342056100010
  • scopus:84907044889
ISSN
1502-7686
DOI
10.3109/00365513.2014.913303
language
English
LU publication?
yes
id
8ee0f677-dce3-4cf9-ace9-8bbac63d0e74 (old id 4451608)
alternative location
http://informahealthcare.com/doi/pdfplus/10.3109/00365513.2014.913303
date added to LUP
2014-06-02 14:43:50
date last changed
2017-01-01 03:53:32
@article{8ee0f677-dce3-4cf9-ace9-8bbac63d0e74,
  abstract     = {Background. The overall purpose of the present study was to attain more insight in month-to-month variation of sleep duration and quality in order to improve design and interpretation of, e.g. epidemiological studies using sleep as outcome. Methods. The study design entailed monthly self-reports from 38 (26 women/12 men) daytime workers, who completed the Karolinska Sleep Diary (KSD) once a month during one year. A subgroup (n = 16) also wore actigraphs on one day every month during a year. Self-reports of bedtime, time of awakening, sleep duration, individual sleep characteristics, disturbed sleep index (DSI, 4 items) and awakening index (AWI, 3 items) were analyzed together with actigraphy-derived measures. Hours of daylight were used to test for circa-annual variation in statistical models adjusted for intake of hypnotics and alcohol, gender, age and within-person variability. Results. Hours of daylight were found to be associated to self-reported bedtime (p = 0.032) and DSI (p = 0.030), thereby indicating a circa-annual variation. Bedtime was delayed by 1.8 min (95% CI: 0.6-2.9 min) per 1 hour increase in length of daylight. Sleep was slightly more disturbed during the winter. Conclusion. Only circa-annual variation in self-reports of bedtime and DSI were observed in a healthy daytime working population, and the effects were small. Therefore potential bias due to circa-annuality in the studied parameters appears to be of limited concern in adult daytime working populations.},
  author       = {Garde, Anne Helene and Hansen, Åse Marie and Persson, Roger and Österberg, Kai and Ørbæk, Palle and Karlson, Björn and Olsen, Annemarie and Kristiansen, Jesper},
  issn         = {1502-7686},
  keyword      = {Sleep quality,circa-annual variation,human,sleep duration},
  language     = {eng},
  number       = {6},
  pages        = {527--535},
  publisher    = {Informa Healthcare},
  series       = {Scandinavian Journal of Clinical & Laboratory Investigation},
  title        = {Month-to-month variation in sleep among healthy, Scandinavian daytime workers},
  url          = {http://dx.doi.org/10.3109/00365513.2014.913303},
  volume       = {74},
  year         = {2014},
}