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Table 5 Single and multi-air pollutant models

From: Low level air pollution and exacerbation of existing copd: a case crossover analysis

Model Without adjustment With adjustmentb
OR (95 % CI)a -2 log likelihood OR (95 % CI)a -2 log likelihood
Single Pollutant Models
 1. NO2 1.17 1.09 - 1.25 451 1.06 0.98 - 1.16 360
 2. SO2 2.78 2.08 - 3.70 413 2.28 1.64 - 3.19 336
 3. PM2.5 0.93 0.88 - 0.99 467 0.94 0.88 - 1.01 359
Multi-Pollutant Models
 4. NO2 1.04 0.96 - 1.12 412 0.96 0.88 - 1.06 335
  SO2 2.58 1.87 - 3.55   2.43 1.69 - 3.50  
 5. NO2 1.31 1.21 - 1.43 423 1.17 1.05 - 1.30 351
  PM2.5 0.81 0.74 - 0.88   0.87 0.79 - 0.96  
 6. SO2 2.99 2.22 - 4.02 403 2.45 1.75 - 3.45 329
  PM2.5 0.90 0.84 - 0.96   0.91 0.85 - 0.98  
 7. NO2 1.16 1.05 - 1.27 393 1.04 0.93 - 1.17 329
  SO2 2.37 1.71 - 3.28   2.33 1.62 - 3.37  
  PM2.5 0.84 0.77 - 0.91   0.89 0.81 - 0.98  
  1. aOdds Ratios (OR) represent a one unit increase in pollutant concentration (ppb or ug/m3)
  2. bAdjusted for temperature (categorical representation based on cut-offs from RCS) and self-reported respiratory infection