Patient characteristics associated with helmet use
| Patient characteristics | Helmet | No helmet |
| (n=1821) | (n=5338) | |
| Age group, n (%) | ||
| 16–45 | 766 (20.7) | 2928 (79.3) |
| 46–65 | 797 (29.0) | 1955 (71.0) |
| >65 | 258 (36.2) | 455 (63.8) |
| Male gender, n (%) | 1467 (80.6) | 4639 (86.9) |
| Injury Severity Score, median (IQR) | ||
| Intoxicated, n (%) | 310 (17.0) | 2158 (40.4) |
| Uninsured, n (%) | 123 (6.8) | 1021 (19.1) |
| Region | ||
| Northeast | 220 (28.7) | 547 (71.3) |
| South | 422 (19.5) | 1742 (80.5) |
| Midwest | 206 (22.8) | 697 (77.2) |
| West | 777 (30.9) | 1741 (69.1) |
All differences between helmet versus non-helmet groups are significant (p<0.001).