title: Longitudinal risk factors for persistent fatigue in adolescents.
abstract: OBJECTIVE
  To examine whether sedentary behavior, obesity, smoking, and depression are risk factors for persistent fatigue in adolescents.
  
  
  METHODS
  Longitudinal population-based survey.
  
  
  METHODS
  Twenty-eight randomly selected schools in east London, England, in 2001 and 2003.
  
  
  METHODS
  A total of 1880 adolescents (49% male; 81% nonwhite British) aged 11 to 12 years and 13 to 14 years in 2000.
  
  
  METHODS
  Confidential questionnaires completed in class.
  
  
  METHODS
  Persistent fatigue (extreme tiredness twice weekly or more often in the previous month at both surveys), sedentary behavior, physical activity, depressive symptoms, body mass index, and smoking.
  
  
  RESULTS
  Severe fatigue was reported in 11% of participants aged 11 to 14 years and 17% of participants aged 13 to 16 years. Eighty-four participants (4%) reported persistent fatigue. Across both surveys, only 3 pupils reported chronic fatigue syndrome. In multivariate logistic regression, risk of persistent fatigue was independently associated with being sedentary for more than 4 hours per day (odds ratio = 1.6; 95% confidence interval, 1.1-2.3; P = .01), being physically active (odds ratio = 1.5; 95% confidence interval, 1.1-2.3; P = .004), and depressive symptoms (odds ratio = 2.0; 95% confidence interval, 1.5-2.7; P < .001) in the first survey, after adjustment for age, sex, and socioeconomic status. Obesity and smoking were not associated with fatigue.
  
  
  CONCLUSIONS
  Persistent fatigue is common. Being highly sedentary or highly active independently increased the risk of persistent fatigue, suggesting that divergence in either direction from healthy levels of activity increases the risk for persistent fatigue. Mental health is important in the etiology of persistent fatigue. To help define effective preventive strategies, further work is needed on the mechanisms by which these factors contribute to fatigue.
authors.affiliation: General and Adolescent Paediatrics Unit, Institute of Child Health, University College London, England. r.viner@ich.ucl.ac.uk
authors.forename: Russell M
authors.initials: RM
authors.lastname: Viner
authors.forename: Charlotte
authors.initials: C
authors.lastname: Clark
authors.forename: Stephanie J C
authors.initials: SJ
authors.lastname: Taylor
authors.forename: Kam
authors.initials: K
authors.lastname: Bhui
authors.forename: Emily
authors.initials: E
authors.lastname: Klineberg
authors.forename: Jenny
authors.initials: J
authors.lastname: Head
authors.forename: Robert
authors.initials: R
authors.lastname: Booy
authors.forename: Stephen A
authors.initials: SA
authors.lastname: Stansfeld
mesh_terms: D000293:Adolescent; D015992:Body Mass Index; D002648:Child; D002908:Chronic Disease; D003201:Computers / Q000706:statistics & numerical data; D003863:Depression / Q000150:complications*; D015444:Exercise; D005221:Fatigue / Q000145:classification / Q000209:etiology*; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D009765:Obesity / Q000150:complications; D012307:Risk Factors; D012720:Severity of Illness Index; D012907:Smoking / Q000009:adverse effects; D011795:Surveys and Questionnaires; D013690:Television / Q000706:statistics & numerical data; D018910:Video Games / Q000706:statistics & numerical data