|  | Subgroup 1 | Subgroup 2 | Subgroup 3 | p value |
---|---|---|---|---|---|
 |  | (Network distance travelled > = 132.84) & (Aging rate in the residential place > = 21.05) | (Network distance travelled > = 132.84) & (Aging rate in the residential place <21.05) | (Network distance travelled <132.84) |  |
Proportion severely injured (%) | Â | 19.7 | 8.2 | 0.0 | Â |
 |  | (n = 66) | (n = 219) | (n = 31) |  |
Age (mean) | Â | 43.24 | 44.22 | 44.42 | 0.8739 |
Male (%) | Â | 47.0 | 51.8 | 48.4 | 0.7644 |
Time | 0:00–4:00 (%) | 9.1 | 9.1 | 6.5 | 0.9906 |
4:00–8:00 (%) | 9.1 | 8.2 | 6.5 |  | |
8:00–12:00 (%) | 16.7 | 13.2 | 12.9 |  | |
12:00–16:00 (%) | 7.6 | 9.5 | 9.7 |  | |
16:00–20:00 (%) | 37.9 | 35.0 | 32.3 |  | |
20:00–24:00 (%) | 19.7 | 25.0 | 32.3 |  | |
Season | Spring (%) | 28.8 | 27.3 | 22.6 | 0.6710 |
Summer (%) | 24.2 | 21.8 | 19.4 | Â | |
Fall (%) | 27.3 | 23.6 | 19.4 | Â | |
Winter (%) | 19.7 | 27.3 | 38.7 | Â | |
Network distance travelled (mean) (unit:m) | 3032 | 1877 | 53 | <0.0001 | |
National road (%) | 28.8 | 17.7 | 6.5 | 0.0231 | |
Road width more than 5Â m (%) | 60.6 | 54.1 | 48.4 | 0.8552 | |
Densely inhabited district (%) | 71.2 | 84.1 | 77.4 | 0.0589 | |
Aging rate in the residential area (%) | 23.9 | 16.0 | 17.3 | <0.0001 | |
Proportion of lower socioeconomic status in the census enumeration district (mean [SD]) (%) | 39.8 | 41.8 | 39.8 | 0.0767 |