Helmets Decrease Risk of Bicyclist-Related Maxillofacial Injuries But Not Severity

Abstract

Given the increasing use of bicycles for local transportation and recreation, the purpose of the present study was to measure the effects of bicycle helmets on the frequency and severity of maxillofacial injuries. The specific aims were to measure and compare the frequencies and severity of maxillofacial injuries between injured bicyclists who had or had not worn helmets. We implemented a retrospective cohort study and enrolled a sample of bicyclists who had been injured from January 4, 2012 to March 31, 2018 and had presented to Harborview Medical Center for evaluation and treatment. The primary predictor variable was helmet use (yes vs no). The primary outcome variables were 1) the presence of a maxillofacial injury (yes vs no); and 2) injury severity, measured using the Face Abbreviated Injury Scale (FAIS). The other study variables were grouped into demographic or injury-related variables. The appropriate univariate, bivariate, and multivariate logistic regressions statistics were computed, and statistical significance was set at P<.05. The sample included 1379 subjects, with a mean age of 39.6±18.9years (range, 1 to 91years), and 78.4% were male. The frequency of facial injuries between the helmeted and nonhelmeted bicyclists was 17.3% and 30.6%, respectively (relative risk, 0.6; 95% confidence interval, 0.5 to 0.7; P<.0001). The protective effect held after adjusting for age, gender, and alcohol exposure. The FAIS score between the helmeted and nonhelmeted riders was 1.8±0.5 and 1.9±0.6, respectively (P=.8). The helmeted bicyclists were 40% less likely to have a facial injury from bicycle accidents. For those cyclists with a facial injury, however, the injury severity was not different between the helmeted and nonhelmeted wearers. This might have been because, that unlike American football helmets, standard bicycle helmets do not include a face mask to protect the face.