title: Subjective daytime sleepiness in schoolchildren.
abstract: OBJECTIVE
  The aim of this study was to find out how the occurrence of subjective daytime sleepiness (SDS) in schoolchildren had changed after 2 years follow-up and which were the predictors associated with persistence and appearance of SDS.
  
  
  METHODS
  A total of 107 schoolchildren with SDS (Group 1) and an equal number without SDS (Group 2) were chosen to take part in the questionnaire study (age range 12-20 years). The questions concerned sleeping habits, sleep disorders and daytime sleepiness of the child and the family, progress at school and TV/video watching of the child, and social background of the family. A bivariate method (Pearson's chi-square) was used as a statistical tool.
  
  
  RESULTS
  We received 68 replies (64%) from Group 1 and 75 (70%) from Group 2. Fifty-four schoolchildren were still sleepy in Group 1 and 28% had become sleepy in Group 2. The persistence of SDS in Group 1 was related to older age, irregular sleeping habits, frequent night waking and the fathers' sleep difficulties. The appearance of SDS in Group 2 was related to a high average grade at school.
  
  
  CONCLUSIONS
  A delayed sleep phase rhythm and problems staying asleep are obvious causes of persistent SDS, but the stress of schoolwork can also cause daytime sleepiness in schoolchildren.
authors.affiliation: Medical School, University of Tampere, PO Box 607, SF 33101, Tampere, Finland.
authors.forename: O
authors.initials: O
authors.lastname: Saarenpää-Heikkilä
authors.forename: P
authors.initials: P
authors.lastname: Laippala
authors.forename: M
authors.initials: M
authors.lastname: Koivikko
mesh_terms: D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D016022:Case-Control Studies; D016009:Chi-Square Distribution; D002648:Child; D002908:Chronic Disease; D005260:Female; D005387:Finland; D005500:Follow-Up Studies; D006184:Habits; D006801:Humans; D008297:Male; D015999:Multivariate Analysis; D012307:Risk Factors; D012894:Sleep Stages; D012893:Sleep Wake Disorders / Q000150:complications*; D013315:Stress, Psychological / Q000150:complications*; D013334:Students / Q000523:psychology* / Q000706:statistics & numerical data*; D011795:Surveys and Questionnaires; D013690:Television; D013997:Time Factors; D018910:Video Games