Spread of porcine circovirus associated disease (PCVAD) in Ontario (Canada) swine herds: Part I. Exploratory spatial analysis

Table 3 Adjusted hazard ratios for herd-level PCVAD status based on classification of easting into four zones§.

Variable	Estimate (HR)	95% CI		P
<500 km East (zone 1)	referent	-	-	-
500 to <600 km East (zone 2)	1.58	1.16,	2.15	0.003
600 to <700 km East (zone 3)	0.77	0.19,	3.21	0.724
>700 km East (zone 4)	4.29	1.51,	12.18	0.006
PRRSv status (positive)	1.58	0.92,	2.73	0.097
LR χ² = 15.68, df = 4, n = 278, P = 0.0035, AIC = 1732.9
No GOF test could be produced for the model with categorical data Global test of proportional hazard assumption (χ² = 1.69, df = 4, P = 0.79)

ISSN: 1746-6148