Demographic characteristics and matching of groups
| Parameter | Levels | Head injury (n=757) | Other injury controls (n=757) | Community controls (n=757) |
| Gender | Male | 602 (79.5%) | 603 (79.7%) | 603 (79.7%) |
| Female | 155 (20.5%) | 154 (20.3%) | 154 (20.3%) | |
| Age (years) | Mean (SD) | 43.4 (20.9) | 43.8 (20.8) | 44.4 (20.9) |
| SIMD 2006 (quintile)* | 1 | 40 (6.0%) | 44 (6.6%) | 51 (6.8%) |
| 2 | 32 (4.8%) | 31 (4.6%) | 63 (8.4%) | |
| 3 | 48 (7.1%) | 58 (8.7%) | 57 (7.6%) | |
| 4 | 89 (13.2%) | 101 (15.1%) | 126 (16.8%) | |
| 5 | 463 (68.9%) | 435 (65.0%) | 454 (60.5%) |
↵* Higher quintiles are associated with greater deprivation.