Risk factors for persistent problems following acute whiplash injury: update of a systematic review and meta-analysis.

Study Design: Systematic review and meta-analysis.

Objective: To update a previous review and meta-analysis on risk factors for persistent problems following whiplash secondary to a motor vehicle accident.

Background: Prognosis in whiplash-associated disorder (WAD) has become an active area of research, perhaps owing to the difficulty of treating chronic problems.