title: C-reactive protein levels and sleep disturbances: observations based on the Northern Finland 1966 Birth Cohort study.
abstract: OBJECTIVE
  To investigate whether sleep disturbances are associated with C-reactive protein (CRP) levels at the population level. Elevated CRP levels have been found to accompany sleep disturbances, but evidence so far comes only from limited clinical and experimental studies; epidemiological studies are lacking.
  
  
  METHODS
  We utilized the Northern Finland 1966 Birth Cohort, whose participants have been followed up to the age of 31 years. The hs-enzyme immunoassay method was used to measure highly sensitive-CRP (hs-CRP) concentrations (4011 participants). Self-reported sleep disturbances were ranked from 1 (no problem) to 5 (severe disturbances).
  
  
  RESULTS
  Multivariate analyses, after adjusting for confounders, revealed that hs-CRP levels in men in the sleep disturbance category "moderate, considerable and severe" (i.e., self-reported sleep disturbances rated 3, 4, or 5), were >18% (18.2%, 95% Confidence Interval 3.0% to 36.3%) higher than those in men with "no" sleep disturbance. In women, hs-CRP levels did not significantly differ between different sleep disturbance categories.
  
  
  CONCLUSIONS
  Our results support the hypothesis that moderate-to-severe sleep disturbances in men are associated with slightly increased CRP levels at the epidemiological level. Further investigations are called for to see whether our results can be replicated in other databases.
authors.affiliation: Department of Psychiatry, Savonlinna Central Hospital Keskussairaalantie 6, FIN-57120 Savonlinna, Finland. liukkonen.timo@dnainternet.net
authors.forename: Timo
authors.initials: T
authors.lastname: Liukkonen
authors.forename: Pirkko
authors.initials: P
authors.lastname: Räsänen
authors.forename: Aimo
authors.initials: A
authors.lastname: Ruokonen
authors.forename: Jaana
authors.initials: J
authors.lastname: Laitinen
authors.forename: Jari
authors.initials: J
authors.lastname: Jokelainen
authors.forename: Maija
authors.initials: M
authors.lastname: Leinonen
authors.forename: V Benno
authors.initials: VB
authors.lastname: Meyer-Rochow
authors.forename: Markku
authors.initials: M
authors.lastname: Timonen
mesh_terms: D000328:Adult; D002097:C-Reactive Protein / Q000032:analysis*; D015331:Cohort Studies; D005260:Female; D005387:Finland / Q000453:epidemiology; D006801:Humans; D008297:Male; D012737:Sex Factors; D012893:Sleep Wake Disorders / Q000097:blood* / Q000453:epidemiology
chemical_list: D002097:C-Reactive Protein