Table 2.
Results from the univariate analyses of risk factors for gastrointestinal illness in Birkebeinerrittet participants in Norway in 2010
| Exposure | Exposed | Unexposed | RR | 95% CI | P | ||||
|---|---|---|---|---|---|---|---|---|---|
| Total | Cases | AR % | Total | Cases | AR % | ||||
| Cycling in Saturday's race | 9131 | 521 | 5·71 | 2590 | 51 | 1·97 | 3·08 | (2·32–4·10) | 0·000 |
| Mud in the face | 10 483 | 548 | 5·23 | 1217 | 23 | 1·89 | 2·85 | (1·89–4·31) | 0·000 |
| Mud in the mouth | 7359 | 449 | 6·10 | 4336 | 122 | 2·81 | 2·21 | (1·82–2·69) | 0·000 |
| Not having a rear mudguard | 8363 | 469 | 5·61 | 3321 | 102 | 3·07 | 1·87 | (1·52–2·31) | 0·000 |
| Not having a front mudguard | 7289 | 426 | 5·84 | 4395 | 145 | 3·30 | 1·83 | (1·52–2·20) | 0·000 |
| Taking more than 5 h to finish | 7482 | 419 | 5·60 | 4207 | 151 | 3·59 | 1·58 | (1·32–1·90) | 0·000 |
| Spitting the first sip of the bottle | 7080 | 401 | 5·66 | 4579 | 170 | 3·71 | 1·56 | (1·31–1·86) | 0·000 |
| Using cycling gloves | 11 468 | 563 | 4·91 | 200 | 7 | 3·50 | 1·46 | (0·70–3·03) | 0·305 |
| Cycling ‘on the wheel’ | 6276 | 350 | 5·58 | 4973 | 202 | 4·06 | 1·39 | (1·18–1·65) | 0·000 |
| Using drinking bottle | 6380 | 331 | 5·19 | 642 | 25 | 3·89 | 1·32 | (0·89–1·97) | 0·162 |
| Drinking rehydrating drink | 9864 | 496 | 5·03 | 1857 | 76 | 4·09 | 1·24 | (0·98–1·57) | 0·073 |
| Being a male participant | 9805 | 497 | 5·07 | 1839 | 74 | 4·02 | 1·23 | (0·97–1·56) | 0·091 |
| Having cycled in the 2009 race | 6791 | 352 | 5·18 | 4838 | 217 | 4·49 | 1·17 | (0·99–1·38) | 0·062 |
| Using communal changing area/shower | 7282 | 372 | 5·11 | 4408 | 199 | 4·51 | 1·14 | (0·97–1·35) | 0·114 |
| Bringing own food | 7784 | 396 | 5·09 | 3903 | 175 | 4·48 | 1·14 | (0·96–1·36) | 0·139 |
| Using drinking bottle with cover | 6097 | 320 | 5·25 | 4471 | 207 | 4·63 | 1·13 | (0·95–1·34) | 0·166 |
| Spitting out mud in mouth | 5044 | 316 | 6·26 | 2291 | 132 | 5·76 | 1·09 | (0·90–1·33) | 0·382 |
| Drinking from a ‘camelbak’ | 6085 | 308 | 5·06 | 3528 | 167 | 4·73 | 1·08 | (0·90–1·30) | 0·386 |
| Rinsing with water (if mud in mouth) | 849 | 55 | 6·48 | 6485 | 390 | 6·01 | 1·07 | (0·82–1·41) | 0·612 |
| Taking off cycling gloves to eat | 739 | 38 | 5·14 | 10 866 | 531 | 4·89 | 1·04 | (0·76–1·44) | 0·798 |
| Using drinking cups/cartons | 5802 | 294 | 5·07 | 4243 | 211 | 4·97 | 1·03 | (0·87–1·22) | 0·739 |
| Drinking plain water | 5248 | 235 | 4·48 | 6473 | 337 | 5·21 | 0·84 | (0·72–0·99) | 0·040 |
| Falling off the bike | 1596 | 65 | 4·07 | 10 059 | 504 | 5·01 | 0·82 | (0·64–1·06) | 0·130 |
AR, Attack rate; RR, risk ratio; CI, confidence interval.