22 August 2018

The results of the cohort study were reported in the Journal of Sleep Research.

– The published results complement our understanding of sleep quality in the general population, says assistant chief medical officer Christer Hublin, FIOH.

– Even though temporary sleeping disorders seem to have become more commonplace, the majority of people experience that they sleep well or fairly well. The research results are positive considering the multitude of connections between sleep and general health.

Differences in results explained by differences in research methods

The participants in the research answered a survey four times in the years of 1975, 1981, 1990 and 2011. Only a very small fraction of the adults in this long follow-up consistently slept poorly.

Of all the adults, 71 per cent slept well or fairly well at each time-point throughout the follow-up and one out of two hundred people slept poorly or fairly poorly.

– In this research study we were asking about the quality of sleep in general whereas earlier research studies have focused on the level of sleep disturbances experienced over the previous month. Temporary sleep disturbances are very common in the population and these can also be experienced by people who sleep well in the longer term, says professor Jaakko Kaprio from the University of Helsinki.

Significant connection between sleep and health

The cohort study also investigated if health problems and age have a connection with sleep quality. Sleeping poorly or fairly poorly was reported 15 times more frequently by those rating their health as fairly poor than by those rating their health as very good. There was a strong association between indicators of depression and poor sleep.

Changes in sleep quality with age – A 36-year follow-up study of Finnish working-aged adults followed the sleep quality of 4847 people that represented the general population. At the start of the survey the average age of the group was 24. The survey was conducted four times between the years 1975 and 2011.


The research article

Hublin C, Lehtovirta M, Partinen M, Koskenvuo M, Kaprio J. Changes in sleep quality with age – A 36-year follow-up study of Finnish working-aged adults. Journal of Sleep Research 2018; 27:

Additional information

Assistant chief medical officer Christer Hublin, FIOH, tel. 043 825 7448, 030 474 2120, christer.hublin[at]ttl.fi

Professor Jaakko Kaprio, University of Helsinki, 050 371549