Table 3.
Multiple variate analysis of risk factors
| Predictor | Estimate | SE | p |
|---|---|---|---|
| Farm positive in Survey 1 |
0.264 |
0.3120 |
0.398 |
| Season |
|
|
0.680 |
| Spring |
0.132 |
0.4293 |
0.758 |
| Summer |
0.478 |
0.4198 |
0.254 |
| Autumn |
0.220 |
0.4218 |
0.603 |
| Winter |
- |
- |
- |
| Farm in sampling cluster positive |
1.719 |
0.6085 |
<0.001 |
| Animal Health Division (AHD) |
|
|
0.686 |
| Island |
−0.907 |
0.8698 |
0.298 |
| Highland |
0.128 |
0.6842 |
0.852 |
| North East |
−0.553 |
0.7340 |
0.451 |
| Central |
0.555 |
0.6139 |
0.367 |
| South East |
0.827 |
0.5956 |
0.166 |
| South West |
- |
- |
- |
| Farm in sampling cluster positive*AHD |
|
|
0.004 |
| Farm in sampling cluster positive in Islands |
2.215 |
1.1426 |
0.053 |
| Farm in sampling cluster positive in Highland |
1.801 |
0.6558 |
0.006 |
| Farm in sampling cluster positive in North East |
2.441 |
0.7202 |
0.001 |
| Farm in sampling cluster positive in Central |
−0.373 |
0.6894 |
0.589 |
| Farm in sampling cluster positive in South East |
−0.417 |
0.5948 |
0.484 |
| Farm in sampling cluster positive in South West |
1.719 |
0.6085 |
0.005 |
| Total number of cattlea |
1.401 |
0.3916 |
<0.001 |
| No. of movements onto farm in last 8 weeksa |
0.774 |
0.3658 |
0.035 |
| Overall OR b | 2.61 (0.79) | ||
Results of the logistic regression model of risk factors for the presence of E. coli O157 on the 447 Scottish farms that were sampled in both Survey 1 (SEERAD, 1998-2000) and Survey 2 (IPRAVE, 2002-2004). Overall OR gives empirical estimate of odds ratio for the entire model.
alog10 transformed.
bMean (SD).