Month-to-month variation in sleep among healthy, Scandinavian daytime workers.
Scand J Clin Lab Invest
; 74(6): 527-35, 2014 Sep.
Article
en En
| MEDLINE
| ID: mdl-24824844
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.Palabras clave
Texto completo:
1
Colección:
01-internacional
Banco de datos:
MEDLINE
Asunto principal:
Sueño
/
Salud Laboral
/
Voluntarios Sanos
Tipo de estudio:
Prognostic_studies
/
Risk_factors_studies
Límite:
Humans
País/Región como asunto:
Europa
Idioma:
En
Revista:
Scand J Clin Lab Invest
Año:
2014
Tipo del documento:
Article
País de afiliación:
Dinamarca