title: Olympic boxing is associated with elevated levels of the neuronal protein tau in plasma.
abstract: OBJECTIVE
  The aim of this study was to investigate if olympic (amateur) boxing is associated with elevation of brain injury biomarkers in peripheral blood compared to controls.
  
  
  METHODS
  Thirty olympic boxers competing in at least 47 bouts were compared to 25 controls. Blood was collected from the controls at one occasion and from the boxers within 1-6 days after a bout and after a rest period of at least 14 days. Tau concentration in plasma was determined using a novel single molecule ELISA assay and S-100B, glial fibrillary acidic protein, brain-derived neurotrophic factor and amyloid β 1-42 were determined using standard immunoassays.
  
  
  RESULTS
  None of the boxers had been knocked-out during the bout. Plasma-tau was significantly increased in the boxers after a bout compared to controls (mean ± SD, 2.46 ± 5.10 vs. 0.79 ± 0.961 ng L(-1), p = 0.038). The other brain injury markers did not differ between the groups. Plasma-tau decreased significantly in the boxers after a resting period compared to after a bout (p = 0.030).
  
  
  CONCLUSIONS
  Olympic boxing is associated with elevation of tau in plasma. The repetitive minimal head injury in boxing may lead to axonal injuries that can be diagnosed with a blood test.
authors.affiliation: Department of Orthopaedics, Sahlgrenska University Hospital , Gothenburg , Sweden. sanna.neselius@vgregion.se
authors.forename: Sanna
authors.initials: S
authors.lastname: Neselius
authors.forename: Henrik
authors.initials: H
authors.lastname: Zetterberg
authors.forename: Kaj
authors.initials: K
authors.lastname: Blennow
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Randall
authors.forename: David
authors.initials: D
authors.lastname: Wilson
authors.forename: Jan
authors.initials: J
authors.lastname: Marcusson
authors.forename: Helena
authors.initials: H
authors.lastname: Brisby
mesh_terms: D000293:Adolescent; D000328:Adult; D016229:Amyloid beta-Peptides / Q000097:blood*; D015415:Biomarkers / Q000097:blood; D001914:Boxing / Q000293:injuries*; D001930:Brain Injuries / Q000097:blood* / Q000453:epidemiology / Q000209:etiology* / Q000503:physiopathology; D019208:Brain-Derived Neurotrophic Factor / Q000097:blood*; D003071:Cognition; D004522:Educational Status; D005260:Female; D005500:Follow-Up Studies; D015600:Glasgow Coma Scale; D005904:Glial Fibrillary Acidic Protein / Q000097:blood*; D006801:Humans; D008297:Male; D009414:Nerve Growth Factors / Q000097:blood*; D011446:Prospective Studies; D064568:S100 Calcium Binding Protein beta Subunit; D009418:S100 Proteins / Q000097:blood*; D011795:Surveys and Questionnaires; D013548:Sweden / Q000453:epidemiology; D016875:tau Proteins / Q000097:blood*
chemical_list: D016229:Amyloid beta-Peptides; D015415:Biomarkers; D019208:Brain-Derived Neurotrophic Factor; D005904:Glial Fibrillary Acidic Protein; D009414:Nerve Growth Factors; D064568:S100 Calcium Binding Protein beta Subunit; D009418:S100 Proteins; D016875:tau Proteins