Univariate comparison of relationship between candidate risk factor and cases with potentially severe head injuries
| 2002 (262/3276) | 2010 (387/4396) | 2011 (276/3436) | |||||||
|---|---|---|---|---|---|---|---|---|---|
| Cases (n) | Per cent | p Value | Cases (n) | Per cent | p Value | Cases (n) | Per cent | p Value | |
| Helmet use | <0.001 | <0.001 | 0.06 | ||||||
| Yes | 37 (14) | 4.7 | 247 (63) | 8.3 | 201 (73) | 7.7 | |||
| No | 223 | 9.1 | 124 | 12.6 | 64 | 10.0 | |||
| Age | 0.09 | <0.001 | 0.68 | ||||||
| <13 | 25 (72) | 5.5 | 46 (97) | 6.9 | 43 (95) | 7.7 | |||
| 13–20 | 116 (9) | 8.3 | 118 (82) | 7.8 | 105 (81) | 7.4 | |||
| >20 | 117 (7) | 8.4 | 209 (54) | 11.6 | 117 (60) | 9.1 | |||
| Gender | <0.001 | 0.13 | 0.05 | ||||||
| Male | 187 (16) | 9.5 | 247 (68) | 9.5 | 186 (72) | 8.8 | |||
| Female | 75 (10) | 5.9 | 137 (72) | 8.5 | 90 (60) | 7.2 | |||
| Nationality | 0.003 | <0.001 | 0.008 | ||||||
| Norwegian | 161 (16) | 9.4 | 216 (65) | 9.8 | 157 (75) | 8.3 | |||
| Swedish | 35 (8) | 5.5 | 70 (69) | 10.6 | 48 (73) | 10.3 | |||
| Danish | 41 (7) | 6.2 | 50 (64) | 5.6 | (44/65) | 6.6 | |||
| Other | 25 (24) | 9.6 | 50 (76) | 12.3 | 27 (62) | 8.5 | |||
| Skiing ability | 0.004 | 0.20 | 0.002 | ||||||
| Expert | 48 (21) | 10.7 | 72 (84) | 10.1 | 53 (80) | 9.7 | |||
| Good | 90 (10) | 9.5 | 111 (79) | 9.6 | 100 (73) | 9.4 | |||
| Intermediate | 69 (11) | 7.2 | 116 (60) | 9.2 | 65 (72) | 6.7 | |||
| Beginner | 50 (18) | 5.9 | 67 (46) | 8.2 | 40 (65) | 6.1 | |||
| Equipment | 0.55 | 0.73 | 0.07 | ||||||
| Alpine | 120 (15) | 7.5 | 250 (68) | 9.2 | 200 (72) | 8.7 | |||
| Snowboard | 121 (13) | 8.7 | 102 (73) | 8.8 | 61 (71) | 6.5 | |||
| Telemark | 15 (0) | 8.4 | 11 (70) | 11.8 | 8 (65) | 13.3 | |||
| Location | <0.005 | 0.02 | <0.001 | ||||||
| On piste | 189 (13) | 7.6 | 210 (62) | 8.4 | 142 (67) | 5.3 | |||
| Park area | 33 (6) | 12.6 | 92 (85) | 9.9 | 97 (78) | 11.5 | |||
| Off-piste | 18 (17) | 5.7 | 52 (75) | 11.4 | 22 (74) | 6.8 | |||
| Lift | 16 (0) | 11.3 | 16 (75) | 11.5 | 11 (72) | 9.3 | |||
| Rented equipment | 0.08 | 0.11 | 0.04 | ||||||
| Yes | 72 (17) | 6.8 | 98 (71) | 8.3 | 64 (81) | 6.6 | |||
| No | 185 (12) | 8.6 | 258 (77) | 9.6 | 192 (81) | 8.7 | |||
| Skiing instruction | 0.13 | 0.01 | 0.21 | ||||||
| Yes | 70 (14) | 6.9 | 77 (73) | 7.2 | 74 (85) | 8.7 | |||
| No | 173 (12) | 8.4 | 241 (72) | 9.7 | 156 (78) | 7.7 | |||
*p Values are from Fisher's exact tests comparing skiers with and without each of the factors.
†Numbers in parentheses represent the percentage with a helmet in the case and control groups, respectively. The column percentages represent the proportion of total cases (sum of controls and cases) with known helmet use that suffered a potentially severe head injury.