The risk of whiplash-induced medical impairment in rear-end impacts for males and females in driver seat compared to front passenger seat

• Medical impairment study in rear-end impacts using double paired comparison technique
• Gender differences, and driver and front passenger seat positions were studied.
• Female relative risk for medical impairment was 3.1 compared to males.
• Driver position had a doubled relative risk compared to front seat position.

The objective of this study was to study whiplash injury outcome in front-seat occupants in rear-end impacts using double paired comparison technique. The combination of gender, seated position, and outcome was analyzed. Folksam, a Swedish insurance company, has a database of whiplash injuries. A questionnaire was used to collect study data. The response rate was 81%. The inclusion criteria included medical impairment one year after the impact, as judged by medical specialists. The study included rear-end impacts between 1990 and 1999 that resulted in at least one permanent neck injury impairment; in total, 430 impacts with 860 occupants and 444 impairments. Of those suffering impairment, 302 were female and 142 male; 235 were seated in the driver's seat and 209 in the front passenger seat. Relative risk estimates for impairing whiplash injury, by gender and seated position:1.Driver male (DM)/passenger female (PF) relative risk = 0.5 n = 2182.Driver male (DM)/passenger male (PM) relative risk = 1.4 n = 573.Driver female (DF)/passenger female (PF) relative risk = 2.5 n = 1024.Driver female (DF)/passenger male (PM) relative risk = 4.6 n = 67.Females had a relative risk of medical impairment of 3.1 compared to men after adjustment for the average increased risk in the driver position. The driver position had a doubled relative risk compared to the front passenger position. As a conclusion it may be of value to take risk differences between male and female occupants and between driver and front passenger positions into account in future automotive car and seat construction.