Skip to main content

Table 3 Results of the final multivariable negative binomial regression model (n = 846 cases from 153 FSAs)

From: Evaluating area-level spatial clustering of SalmonellaEnteritidis infections and their socioeconomic determinants in the greater Toronto area, Ontario, Canada (2007 – 2009): a retrospective population-based ecological study

Variable a) Type Estimate (95% CI) IRR c)(95% CI) P-value
Average number of children at home per census family Linear (X) b) 0.22 (−0.20, 0.64) 1.24 (0.82, 1.89) 0.313
Quadratic (X^2) 1.69 (0.84, 2.53) 5.40 (2.32, 12.54) <0.001
Average median family income Categorical Low (< CAD d) 65,000) 0.29 (0.11, 0.47) 1.34 (1.12, 1.61) 0.002
Medium (CAD 65,000 - 85,000) Reference - -
High (> CAD 85,000) 0.22 (0.03, 0.40) 1.24 (1.03, 1.49) 0.020
Visible minority population proportion Categorical Low (2.1 - 29.4) −0.16 (−0.35, 0.036) 0.85 (0.70, 1.04) 0.110
Medium (29.5 - 51.8) Reference - -
High (51.9 - 93.4) −0.27 (−0.44, -0.10) 0.76 (0.64, 0.91) 0.002
Intercept - - −0.12 (−0.29, 0.05) - 0.178
  1. a) Dependent variable: Number of Salmonella Enteritidis infections by forward sortation area (FSA). Offset: natural log-transformed FSA-based expected number of cases. b) Each linear (continuous) variable was centered by substracting the mean value from each value. A quadratic term for the centered linear variable was introduced and kept in the model if it was significant. If the linear and quadratic terms were not statistically significant, the variable was categorized into three equal groups (low, medium, and high). c) IRR: incidence rate ratio; CI: confidence interval. d) CAD: Canadian Dollar. Significant at P ≤ 0.05.