Poor Sleep Linked To Missed Work Days

Tea Lallukka, PhD Finnish Institute of Occupational Health & University of Helsinki, Hjelt Institute, Department of Public Health University of Helsinki, FinlandMedicalResearch.com Interview with:
Tea Lallukka, PhD
Finnish Institute of Occupational Health &
University of Helsinki, Hjelt Institute, Department of Public Health
University of Helsinki, Finland

Medical Research: What are the main findings of the study?

Dr. Lallukka: Our study used nationally representative survey data linked with
register data on medically certified sickness absence among working
-aged Finnish women and men. We showed consistent associations between
insomnia symptoms, sleep duration, and being tired and sickness
absence. The follow-up lasted around 7 years.
Sickness absence days were derived from comprehensive registers from
the Social Insurance Institution of Finland. The associations were
broadly similar among women and men. Furthermore, they remained even
after considering key correlates of sleep and sickness absence
including socioeconomic position, working conditions, health
behaviors, obesity, and mental and physical health. Health data were
derived from physical examination conducted by field physicians. These
data are more objective, and help provide more robust evidence. We
further covered all key sleep disturbances and sleep duration for more
comprehensive understanding about the contribution of sleep to
sickness absence. Finally, a novel method developed by the authors
(Härkänen & Kaikkonen) allowed us to estimate the difference in
sickness absence days per working year among those reporting and not
reporting different sleep disturbances. Using the difference in days
absent from work, we were further able to estimate the hypothetical
direct costs of sickness absence highlighting notable societal
significance of sleep. Thus, a large part of all costs of sickness
absence are attributable to poor sleep. For example, those sleeping 5
hours or less or 10 hours or more, were absent from work ca 5-9 days
more, as compared to those with optimal sleep length. The optimal
sleep length with the lowest risk of sickness absence was 7 hours 46
minutes for men and 7 hours 38 minutes for women.

Medical Research: Were any of the findings unexpected?

Dr. Lallukka: The lack of an association between daytime sleepiness, apnea, and
seasonal variation in sleep duration and sickness absence could be
seen as unexpected.

Medical Research: What should clinicians and patients take away from your report?

Dr. Lallukka: Insomnia symptoms should be detected early. This could help prevent
them from becoming chronic, and could help prevent decline in work
ability and subsequent sickness absence. Sufficient quantity and
quality of sleep likely promotes health, well-being, and functioning
among women and men.

Medical Research: What recommendations do you have for future research as a result of  this study?

Dr. Lallukka: As insomnia symptoms are highly prevalent, and increase particularly
after middle-age, it is vital to be able to tackle them early in
efforts to promote employee well-being, wealth and work ability. It
would be important to conduct further research on whether early
detection and prevention of insomnia would lead to less sickness
absence. Mechanisms on how sleep affects work ability and health also
need further elaboration, as the effects remain even after considering
health and working conditions, for example.

Work disability is also a major public health and societal challenge,
bearing huge costs for the employers and society, alongside individual
suffering related to ill- health and economical consequences.


Tea Lallukka, Risto Kaikkonen, Tommi Härkänen, Erkki Kronholm, Timo Partonen, Ossi Rahkonen, Seppo Koskinen. Sleep and Sickness Absence: A Nationally Representative Register-Based Follow-Up Study
SLEEP, 2014; DOI: 10.5665/sleep.3986

Last Updated on October 24, 2015 by Marie Benz MD FAAD