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Table 5 Multivariable random intercept negative binomial model

From: Exploring relationships between whole carcass condemnation abattoir data, non-disease factors and disease outbreaks in swine herds in Ontario (2001–2007)

Variable   IRR P-value Confidence interval
Year 2001 (Referent)   
  2002 1.12 0.66 0.67 – 1.89
  2003 0.99 0.97 0.57 – 1.71
  2004 2.01 0.01 1.22 – 2.39
  2005 1.65 0.06 0.99 – 2.76
  2006 1.13 0.66 0.65 – 1.98
  2007 1.36 0.28 0.78 – 2.35
Season Fall (Referent)   
  Winter 1.10 0.03 1.01 – 1.20
  Spring 1.19 <0.001 1.10 – 1.29
  Summer 1.17 <0.001 1.08 – 1.27
CAR Central Ontario (Referent)   
  Eastern Ontario 1.52 0.21 0.79 – 2.89
  Northern Ontario 1.33 0.54 0.55 – 3.26
  Southern Ontario 2.77 <0.001 1.70 – 4.50
  Western Ontario 1.62 0.06 0.98 – 2.70
Log 10 total processed per year   0.82 <0.001 0.76 – 0.88
Year x CAR 2001 × Central Ont. (Referent)   
  2002 × Eastern Ont. 0.70 0.37 0.33 – 1.52
  2002 × Northern Ont. 0.48 0.26 0.13 – 1.73
  2002 × Southern Ont. 0.96 0.89 0.56 – 1.65
  2002 × Western Ont. 0.83 0.50 0.47 – 1.45
  2003 × Eastern Ont. 0.60 0.24 0.25 – 1.41
  2003 × Northern Ont. 1.21 0.73 0.41 – 3.60
  2003 × Southern Ont. 1.09 0.77 0.62 – 1.92
  2003 × Western Ont. 1.05 0.86 0.59 – 1.89
  2004 × Eastern Ont. 0.37 0.02 0.16 – 0.87
  2004 × Northern Ont. 0.20 0.02 0.05 – 0.80
  2004 × Southern Ont. 0.40 <0.001 0.24 – 0.66
  2004 × Western Ont. 0.86 0.58 0.51 – 1.46
  2005 × Eastern Ont. 0.36 0.03 0.14 – 0.92
  2005 × Northern Ont. 0.49 0.22 0.15 – 1.55
  2005 × Southern Ont. 0.56 0.03 0.33 – 0.95
  2005 × Western Ont. 1.10 0.74 0.64 – 1.89
  2006 × Eastern Ont. 1.07 0.88 0.45 – 2.50
  2006 × Northern Ont. 0.30 0.15 0.06 – 1.56
  2006 × Southern Ont. 1.01 0.98 0.56 – 1.80
  2006 × Western Ont. 0.73 0.31 0.40 – 1.33
  2007 × Eastern Ont. 0.63 0.32 0.25 – 1.57
  2007 × Northern Ont. 0.47 0.30 0.11 – 1.98
  2007 × Southern Ont. 0.72 0.27 0.41 – 1.28
  2007 × Western Ont. 0.69 0.22 0.38 – 1.24
  1. Modeling the association between whole carcass condemnation rate (IRR) and year, season, census agricultural region (CAR), total number of market hogs (pigs) processed per year, and the interaction effect between census agricultural region and year.