title: Risk Factors for Prolonged Treatment of Whiplash-Associated Disorders.
abstract: OBJECTIVE
  Whiplash-associated disorders (WAD) are the most common injuries that are associated with car collisions in Japan and many Western countries. However, there is no clear evidence regarding the potential risk factors for poor recovery from WAD. Therefore, we used an online survey of the Japanese population to examine the association between potential risk factors and the persistence of symptoms in individuals with WAD.
  
  
  METHODS
  An online survey was completed by 127,956 participants, including 4,164 participants who had been involved in a traffic collision. A random sample of the collision participants (n = 1,698) were provided with a secondary questionnaire. From among the 974 (57.4%) respondents to the secondary questionnaire, we selected 183 cases (intractable neck pain that was treated over a period of 6 months) and 333 controls (minor neck pain that was treated within 3 months). Multivariable logistic regression analysis was used to evaluate the potential risk factors for prolonged treatment of WAD.
  
  
  RESULTS
  Female sex, the severity of the collision, poor expectations of recovery, victim mentality, dizziness, numbness or pain in the arms, and lower back pain were associated with a poor recovery from WAD.
  
  
  CONCLUSIONS
  In the present study, the baseline symptoms (dizziness, numbness or pain in the arms, and lower back pain) had the strongest associations with prolonged treatment for WAD, although the psychological and behavioral factors were also important. These risk factors should be considered when evaluating patients who may have the potential for poor outcomes.
authors.affiliation: Department of Medical Research and Management for Musculoskeletal Pain, 22nd Century Medical & Research Center, Faculty of Medicine, University of Tokyo, Tokyo, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Oka
authors.affiliation: Department of Medical Research and Management for Musculoskeletal Pain, 22nd Century Medical & Research Center, Faculty of Medicine, University of Tokyo, Tokyo, Japan.
authors.forename: Ko
authors.initials: K
authors.lastname: Matsudaira
authors.affiliation: Department of Orthopaedic Surgery, Japan Labour, Health and Welfare Organization, Kanto Rosai Hospital, Kanagawa, Japan.
authors.forename: Tomoko
authors.initials: T
authors.lastname: Fujii
authors.affiliation: Department of Orthopaedic Surgery, Japan Labour, Health and Welfare Organization, Kanto Rosai Hospital, Kanagawa, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Okazaki
authors.affiliation: Medical Research Center, JA Kyosai Research Institute, Tokyo, Japan.
authors.forename: Yukari
authors.initials: Y
authors.lastname: Shinkai
authors.affiliation: Medical Research Center, JA Kyosai Research Institute, Tokyo, Japan.
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Tsuji
authors.affiliation: Department of Orthopaedic Surgery, University of Tokyo, Tokyo, Japan.
authors.forename: Sakae
authors.initials: S
authors.lastname: Tanaka
authors.affiliation: Medical Research Center, JA Kyosai Research Institute, Tokyo, Japan.
authors.forename: Ryuichi
authors.initials: R
authors.lastname: Kato
mesh_terms: D000063:Accidents, Traffic; D000328:Adult; D000368:Aged; D044466:Asian People; D005260:Female; D006801:Humans; D007564:Japan / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D019547:Neck Pain / Q000453:epidemiology* / Q000209:etiology; D012307:Risk Factors; D011795:Surveys and Questionnaires; D014911:Whiplash Injuries / Q000150:complications / Q000453:epidemiology*