title: Trends in self-reported sleep duration and insomnia-related symptoms in Finland from 1972 to 2005: a comparative review and re-analysis of Finnish population samples.
abstract: A hypothesis concerning habitual sleep reduction and its adverse consequences among general population in modern societies has received wide publicity in the mass media, although scientific evidence supporting the hypothesis is scarce. Similarly, there is an extensively distributed belief, at least in Finland, that the prevalence of insomnia-related symptoms is increasing, but evidence for this is even sparser. These issues are important because of the known increased risk of mortality and health risks associated with sleep duration deviating from 7 to 8 h. To reveal possible trends in self-reported sleep duration and insomnia-related symptoms, we reanalyzed all available data from surveys carried out in Finland from 1972 to 2005. The main results were that a minor decrease of self-reported sleep duration has taken place in Finland, especially among working aged men. However, the size of the reduction (about 4%) was relatively small, approximately 5.5 min per each 10 years during the 33 years' time interval under study. The proportion of 7 h sleepers has increased and, correspondingly, the proportion of 8 h sleepers has decreased, but the extreme ends of the sleep duration distribution remained unchanged. Tentative evidence suggesting an increase in insomnia-related symptoms among working aged population during the last 10 years was found. In conclusion, the Finnish data during the past 33 years indicate a general decrease in self-reported sleep duration of about 18 min and an increase of sleep complaints, especially among the employed middle-aged population.
authors.affiliation: The National Public Health Institute, Turku, Finland. erkki.kronholm@ktl.fi
authors.forename: Erkki
authors.initials: E
authors.lastname: Kronholm
authors.forename: Timo
authors.initials: T
authors.lastname: Partonen
authors.forename: Tiina
authors.initials: T
authors.lastname: Laatikainen
authors.forename: Markku
authors.initials: M
authors.lastname: Peltonen
authors.forename: Mikko
authors.initials: M
authors.lastname: Härmä
authors.forename: Christer
authors.initials: C
authors.lastname: Hublin
authors.forename: Jaako
authors.initials: J
authors.lastname: Kaprio
authors.forename: Arja R
authors.initials: AR
authors.lastname: Aro
authors.forename: Markku
authors.initials: M
authors.lastname: Partinen
authors.forename: Mikael
authors.initials: M
authors.lastname: Fogelholm
authors.forename: Raisa
authors.initials: R
authors.lastname: Valve
authors.forename: Jussi
authors.initials: J
authors.lastname: Vahtera
authors.forename: Tuula
authors.initials: T
authors.lastname: Oksanen
authors.forename: Mika
authors.initials: M
authors.lastname: Kivimäki
authors.forename: Markku
authors.initials: M
authors.lastname: Koskenvuo
authors.forename: Hanna
authors.initials: H
authors.lastname: Sutela
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D005387:Finland / Q000453:epidemiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D011159:Population Surveillance; D015995:Prevalence; D012892:Sleep Deprivation / Q000453:epidemiology*; D007319:Sleep Initiation and Maintenance Disorders / Q000453:epidemiology*; D011795:Surveys and Questionnaires; D013997:Time Factors