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Table 2 Poisson Regression on Demographic Risks, Temporal Trends, and Testing Effects Associated with Reported Pertussis Risk in the Greater Toronto Area, Canada

From: Pertussis resurgence in Toronto, Canada: a population-based study including test-incidence feedback modeling

  Exclude Testing Volume Include Testing Volume
Variable IRR (95% C.I.) P-value IRR (95% C.I.) P-value
Temporal Trends*     
Seasonal Oscillation --- 0.04 --- < 0.001
Oscillation, 6-year Period --- < 0.001 --- < 0.001
Demographic Characteristics     
Female Gender 1.15 (1.06 to 1.24) < 0.001 1.14 (1.05 to 1.23) < 0.001
Age     
0 to 4 years 57.76 (50.91 to 65.53) < 0.001 38.59 (33.84 to 44.00) < 0.001
5 to 9 years 17.16 (14.78 to 19.93) < 0.001 17.34 (14.94 to 20.14) < 0.001
10 to 14 years 13.14 (11.24 to 15.36) < 0.001 14.81 (12.66 to 17.32) < 0.001
15 to 19 years 3.57 (2.82 to 4.52) < 0.001 4.30 (3.40 to 5.44) < 0.001
20 and over 1 (referent) --- 1 (referent) ---
Testing Practices     
Introduction of Novel, Highly Sensitive PCR (May 2005) 3.75 (3.44 to 4.09) < 0.001 2.31 (2.09 to 2.55) < 0.001
Test Submission Volume (per 10 additional test specimens) --- --- 1.57 (1.53 to 1.61) < 0.001
Pseudo-R2 0.43 0.47
Akaike's Information Criterion 11325 10421
  1. NOTE: IRR, incidence rate ratio; CI, confidence interval.
  2. * P-values for oscillation based on sine and cosine terms for oscillation at yearly and 6-yearly intervals.