title: A systematic review of age and gender factors in prolonged post-concussion symptoms after mild head injury.
abstract: BACKGROUND
  Older age and female gender are known factors in the development of persisting post-concussion symptoms (PCS) after mild head injury (MHI), i.e. at 3+ months. Very few studies have examined longer-term symptoms. A recent review, however, established the importance of these variables in permanent PCS (18+ months). The current study repeats the review for prolonged symptoms (12-18 months).
  
  
  METHODS
  Systematic electronic database searches were conducted to identify all studies with data on (i) correlations between age/gender and prolonged outcome and (ii) mean ages/gender mixes of (a) prolonged samples selected for poor symptomatic outcome, (b) prolonged samples not selected for poor outcome and (c) epidemiological studies of MHI patients presenting to hospital.
  
  
  RESULTS
  Correlation studies showed poorer outcome to be associated with both older age (2/5 studies) and female gender (5/6 studies). Those with poor prolonged outcome had a significantly higher mean age (35.9) than MHI patients in general (29.9). The proportion of men in these samples (48.6%) was significantly lower than MHI patients in general (66.7%).
  
  
  CONCLUSIONS
  Older age and female gender are vulnerability factors in the development of prolonged PCS. The main clinical implications are for how early intervention and reassurance are best provided.
authors.affiliation: Community Head Injury Service, The Camborne Centre , Aylesbury, Bucks , UK and.
authors.forename: Nigel S
authors.initials: NS
authors.lastname: King
mesh_terms: D000367:Age Factors; D003071:Cognition; D006259:Craniocerebral Trauma / Q000150:complications / Q000453:epidemiology* / Q000503:physiopathology; D004185:Disability Evaluation; D018450:Disease Progression; D005260:Female; D006801:Humans; D015601:Injury Severity Score; D008297:Male; D009483:Neuropsychological Tests; D038223:Post-Concussion Syndrome / Q000453:epidemiology* / Q000503:physiopathology; D011379:Prognosis; D012307:Risk Factors; D012737:Sex Factors; D013997:Time Factors
keywords: Mild head injury; prolonged post-concussion symptoms