Adult Bicycle Collisions: Impact of Helmet Use on Head and Cervical Spine Injury.

BACKGROUND

No states currently require adult bicycle riders to wear helmets. Opponents of a universal helmet law argue that helmets may cause a greater torque on the neck during collisions, potentially increasing the risk of cervical spine fracture (CSF). This assumption has not been supported by data for motorcyclists. Therefore, we sought to evaluate the risk of CSF and cervical spinal cord injury (CSCI) in helmeted bicyclists (HBs) versus nonhelmeted bicyclists (NHBs) involved in collisions. We hypothesize that in adult HBs, there is an increased incidence of CSF and injury but lower rates of severe head injury and mortality than in NHBs.

MATERIALS AND METHODS

The Trauma Quality Improvement Program (2010-2016) was queried for adult bicyclists involved in collisions, comparing HBs with NHBs. A multivariable logistic regression model was used for analysis.

RESULTS

Of 25,047 bicyclists, 14,234 (56.8%) were NHBs. NHBs were more often black (13.3% versus 2.3%, P < 0.001) and screened positive for alcohol on admission (25.7% versus 4.6%, P < 0.001). NHBs had lower rates of CSF (17.7% versus 23.7%, P < 0.001) and CSCI (1.1% versus 1.9%, P < 0.001) but higher rates of mortality (4.9% versus 2.2%, P < 0.001) and a higher risk for severe head injury (odds ratio [OR]: 2.26, 2.13-2.40, P < 0.001). After adjusting for covariates, NHBs had a higher risk of mortality (OR: 2.38, 2.00-2.84, P < 0.001) but lower risk of CSF (OR: 0.66 0.62-0.71, P < 0.001) and CSCI (OR: 0.53, 0.42-0.68, P < 0.001).

CONCLUSIONS

HBs involved in collisions have a higher risk of CSF and CSCI; however, NHBs have a higher risk of severe head injury and mortality. Consideration for a universal helmet law among bicyclists and ongoing research regarding helmet development is needed.