Motorcycle helmets associated with lower risk of cervical spine injury: debunking the myth

Background: There has been a repeal of the universal helmet law in several states despite definitive evidence that helmets reduce mortality, traumatic brain injury, and hospital expenditures. Opponents of the universal helmet law have successfully claimed that helmets should not be required because of greater torque on the neck, which is thought to increase the likelihood of a cervical spine injury. There is currently insufficient evidence to counter claims that helmets do not increase the risk of cervical spine injury after a motorcycle collision. The objective of this study was to determine the impact of motorcycle helmets on the likelihood of developing a cervical spine injury after a motorcycle collision.

Study design: We reviewed cases in the National Trauma Databank (NTDB) v7.0 involving motorcycle collisions. Multiple logistic regression was used to analyze the independent effect of helmets on cervical spine injury. Cases were adjusted for age, race, sex, insurance status, anatomic (Injury Severity Score) and physiologic injury severity (systolic blood pressure < 90 mmHg), and head injury (Abbreviated Injury Score > 3).

Results: Between 2002 and 2006, 62,840 cases of motorcycle collision were entered into the NTDB; 40,588 had complete data and were included in the adjusted analysis. Helmeted riders had a lower adjusted odds (0.80 [CI 0.72 to 0.90]) and a lower proportion of cervical spine injury (3.5% vs 4.4%, p < 0.05) compared with nonhelmeted riders.

Conclusions: Helmeted motorcyclists are less likely to suffer a cervical spine injury after a motorcycle collision. This finding challenges a long-standing objection to mandatory helmet use that claims helmets are associated with cervical spine injury. Re-enactment of the universal helmet law should be considered in states where it has been repealed.