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Table 2 Odds ratios from logistic regression indicating associations between exposure variables and the odds of having FMD in the previous 6 months

From: Knowledge and risk factors for foot-and-mouth disease among small-scale dairy farmers in an endemic setting

Univariable analysis Multivariable analysis
Variable Type of variable Odds ratio (95% CI) p value Odds ratio (95% CI) p value
Use of a shared bull Categorical     
 Did not use a shared bull   Base category   Base category  
 Used a shared bull   12.7 (0.4–396.4) 0.147 9.7 (1.6–59.1) 0.014
 Did not respond to the question   15.4 (2.1–112.5) 0.007 3.4 (0.4–25.1) 0.238
Number of additional cattle sourced from outside the farm in the previous 12 months Continuous 1.2 (1.0–1.5) 0.043 1.1 (1.0–1.3) 0.207
Buying cattle from livestock markets in the previous 12 months Categorical 3.9 (1.3–12.4) 0.019  
Grazing sheep within towns Categorical 34.5 (3.5–337.8) 0.002  
Grazing cattle within towns Categorical 8.3 (1.6–43.4) 0.012  
Use of communal dips Categorical 8.6 (2.3–32.8) 0.002  
Number of sheep Continuous 1.1 (1.0–1.2) 0.025 1.1 (1.0–1.2) 0.066
Ever vaccinated cattle for FMD Categorical 0.2 (0.07–0.7) 0.013  
Subcounty Categorical    
 Njoro   Base category   Base category  
 Molo   5.3 (0.2–133.5) 0.307 4.5 (0.2–113.6) 0.365
 Rongai   37.4 (2.2–643.2) 0.013 30.0 (1.7–528.9) 0.020
  1. From the univariable analysis, only variables with a p-value < 0.2 are included (a list of all examined variables is reported in Additional file 1) which were taken forward into the final multivariable model using a backward-stepwise approach. Subcounty of the interviewed farm was included a priori as a fixed effect to account for potential spatial autocorrelation. Variables were retained in the final model if the likelihood ratio test had a p-value less than 0.2. The final multivariable model had a Wald Chi square of 20.0 with 6 degrees of freedom giving a p value of 0.0027. The model had an AIC of 64.5, a BIC of 95.0 and a McFadden’s R2 of 0.443.