The Impact of Helmet Use on Head Injury Characteristics and Medical Management Following Helmet-Relevant Activity-Associated Traumatic Brain Injury: A 2014-2021 National Trauma Data Bank Retrospective Cohort Analysis.

Traumatic brain injury (TBI) is a major global health burden, with sports and recreational activities accounting for approximately 10% of all TBI cases in the United States. Helmets are widely used to mitigate head injury risk, yet prior studies have reported conflicting associations between helmet use and specific head injury patterns, medical management, and outcomes across different helmet-relevant activities. The objective of this study is to examine the associations between helmet use and head injury characteristics, injury severity, and emergency department (ED) disposition among patients with helmet-associated activity-relevant TBI. We conducted a retrospective cohort study using the National Trauma Data Bank (NTDB) research dataset (2014-2021). Patients with TBI resulting from cycling/motorcycling, skiing/snowboarding, roller-skating/skateboarding, and equestrian-related activities were included. Primary outcomes include TBI severity (based on Glasgow Coma Scale score), head injury severity scale (ISS) maximum score, loss of consciousness (LOC), intracranial hemorrhage (ICH), skull fracture, diffuse axonal injury (DAI), and ED disposition. Multivariable regression models were estimated using an inclusive analytic approach along with sensitivity analyses using complete-case analysis and multiple imputation for missing covariate data. A total of 174,892 patients were included, of whom 70,558 were helmeted and 97,606 were non-helmeted. In adjusted inclusive analyses, helmet use was associated with lower odds of more severe TBI (odds ratio [OR] = 0.60, 95% confidence interval [CI]: 0.58-0.61, p < 0.001), higher head ISS maximum scores (OR = 0.59, 95% CI: 0.58-0.60, p < 0.001), ICH (OR = 0.61, 95% CI: 0.60-0.62, p < 0.001), and skull fracture (OR = 0.35, 95% CI: 0.34-0.36, p < 0.001). Helmeted patients had slightly higher odds of LOC (OR = 1.06, 95% CI: 1.03-1.08; p < 0.001). To assess whether this association reflected increased rotational injury, analyses restricted to patients in the International Classification of Diseases, Tenth Revision (ICD-10)-era demonstrated that helmet use was associated with lower odds of DAI (OR = 0.87, 95% CI: 0.81-0.93; p < 0.001). Helmet use was also associated with substantially lower odds of high-acuity or adverse ED dispositions. Findings were consistent across inclusive, complete-case, and multiple imputation analyses. In conclusion, our findings suggest that helmet use in helmet-relevant activity-associated injuries is associated with reduced head injury severity, lower odds of ICH, skull fracture, DAI, and decreased need for high-acuity medical care. The observed increase in LOC among helmeted patients may reflect differences in reporting or injury biomechanics rather than greater injury severity. These findings support public health strategies to increase helmet use through policy, education, and advances in protective equipment design.