Table 2 Cox proportional hazard models for the exposure groups by birth cohort, with the naturally exposed VLA scrapie flock birth cohorts as the baseline categories.

2003 birth cohort

Baseline

2

0.98

0.30 - 3.22

0.969

3

2.70

0.92 - 7.95

0.071

4

1.04

0.40 - 2.66

0.942

8

0.03

0.005 - 0.17

< 0.001

9

0.09

0.02 - 0.34

< 0.001

11

0.60

0.23 - 1.52

0.279

12

1.25

0.44 - 3.58

0.680

13

0.87

0.34 - 2.25

0.774

Overall model

< 0.001

Model 2

2002 birth cohort

Baseline

5

0.31

0.08 - 1.20

0.091

6

0.22

0.06 - 0.84

0.027

7

0.46

0.14 - 1.51

0.198

10

0.12

0.03 - 0.47

0.002

Overall model

0.032