title: Self-reported sleep duration and cognitive functioning in the general population.
abstract: This study investigated the relationship between self-reported sleep factors (sleep duration, insomnia, use of sleeping medicine, probable sleep apnoea and feelings of fatigue and tiredness) with cognitive functioning in 5177 people aged 30 years or older from a cross-sectional representative sample of the adult population in Finland (The Finnish Health 2000 Survey). Previous studies have indicated a U-shaped association between increased health risks and sleep duration; we hypothesized a U-shaped association between sleep duration and cognitive functioning. Objective cognitive functioning was assessed with tasks derived from the Consortium to Establish a Registry for Alzheimer's Disease test battery (verbal fluency, encoding and retaining verbal material). Subjective cognitive functioning and sleep-related factors were assessed with questionnaires. Health status was assessed during a health interview. Depressive and alcohol use disorders were assessed with the Composite International Diagnostic Interview. Medication was recorded during the health examination. Short and long sleep duration, tiredness and fatigue were found to be associated with both objectively assessed and self-reported decreased cognitive functioning. The association was stronger between sleep factors and subjective cognitive function than with objective cognitive tests. These data suggest that self-reported habitual short and long sleep duration reflect both realization of homeostatic sleep need and symptom formation in the context of the individual's health status.
authors.affiliation: Department of Chronic Disease Prevention, National Institute for Health and Welfare, Turku, Finland. erkki.kronholm@thl.fi
authors.forename: Erkki
authors.initials: E
authors.lastname: Kronholm
authors.forename: Mikael
authors.initials: M
authors.lastname: Sallinen
authors.forename: Timo
authors.initials: T
authors.lastname: Suutama
authors.forename: Raimo
authors.initials: R
authors.lastname: Sulkava
authors.forename: Pertti
authors.initials: P
authors.lastname: Era
authors.forename: Timo
authors.initials: T
authors.lastname: Partonen
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D003072:Cognition Disorders / Q000175:diagnosis / Q000453:epidemiology / Q000523:psychology*; D003430:Cross-Sectional Studies; D006970:Disorders of Excessive Somnolence / Q000175:diagnosis / Q000453:epidemiology / Q000523:psychology*; D005221:Fatigue / Q000453:epidemiology / Q000523:psychology; D005260:Female; D005387:Finland; D015577:Geriatric Assessment; D006305:Health Status Indicators; D006306:Health Surveys; D006801:Humans; D007600:Judgment; D008297:Male; D008569:Memory Disorders / Q000175:diagnosis / Q000453:epidemiology / Q000523:psychology; D008875:Middle Aged; D009483:Neuropsychological Tests / Q000706:statistics & numerical data; D011594:Psychometrics / Q000706:statistics & numerical data; D015203:Reproducibility of Results; D012650:Self Disclosure; D020181:Sleep Apnea, Obstructive / Q000175:diagnosis / Q000453:epidemiology / Q000523:psychology; D012892:Sleep Deprivation / Q000175:diagnosis / Q000453:epidemiology / Q000523:psychology*; D012959:Socioeconomic Factors; D013223:Statistics as Topic; D011795:Surveys and Questionnaires