Abstract

Objectives: To investigate potential risk factors for whiplash injury as a function of crash configuration and driver’s characteristics, and to provide information on over-reporting and under-reporting of whiplash.

Design: A case–control study of drivers involved in two-car injury collisions. Cases were drivers who had a diagnosis of whiplash injury, with or without another injury. Controls were drivers without diagnosed whiplash injury.

Setting: Hospital registries linked to police crash databases for Barcelona (Spain) and the “Département du Rhône” (France).

Main outcome measures: Relative risks of whiplash and 95% confidence intervals were estimated using a modified Poisson regression.

Results: Of the 8720 drivers involved in car-to-car crashes recorded in the French database, 12.2% were diagnosed with whiplash; the corresponding figure in the Spanish database was 12.0% of 7558 drivers. Female drivers and drivers in rear-impact collisions were most likely to have a whiplash diagnosis, although the absolute number of whiplash cases was greater in front and side impacts. Wearing a seatbelt, being in a heavier car, and age greater than 65 years were associated with a lower risk of whiplash injury. Drivers with other injuries were also more often diagnosed as having a whiplash injury, except the most severely injured.

Conclusions: Devices aimed at reducing the occurrence of whiplash injuries, such as dynamic headrest systems, should be adapted to the characteristics of at-risk occupants, especially women, and should address the mechanics of front and side impacts in addition to rear impacts.