Table III.
Associations of carbon monoxide with FEV1 % predicted: models with single averaging periods are compared to models combining shorter (one day or one week) and longer (4-month) averaging periods
| Pre bronchodilator FEV1 % predicted | ||||||
|---|---|---|---|---|---|---|
| MODEL 1 Change (95%CI) per IQR P-value |
MODEL 2 change (95%CI) per IQR P-value |
MODEL 3 change (95%CI) per IQR P-value |
MODEL 4 change (95%CI) per IQR P-value |
MODEL 5 change (95%CI) per IQR P-value |
||
| Carbon Monoxide | IQR (ppm ×10) | |||||
| Same day | 5 | −0.13 (−0.29, 0.02) P=0.09 |
−0.08 (−0.24, 0.08) P=0.310 |
|||
| 1 week average | 4 | −0.19 (−0.39, 0.001) P=0.05 |
−0.12 (−0.33, 0.09) P=0.269 |
|||
| 4 month average | 3 | −0.36 (−0.62, −0.10) P=0.006 |
||||
| 4 month average excluding same day | 3 | −0.33 (−0.59, −0.06) P=0.016 |
||||
| 4 month average excluding 1 week | 3 | −0.29 (−0.56,−0.02) P=0.037 |
||||
| Post bronchodilator FEV1 %predicted | ||||||
|---|---|---|---|---|---|---|
| MODEL 2 change (95%CI) per IQR P-value |
MODEL 2 change (95%CI) per IQR P-value |
MODEL 2 change (95%CI) per IQR P-value |
MODEL 2 change (95%CI) per IQR P-value |
MODEL 2 change (95%CI) per IQR P-value |
||
| Carbon Monoxide | IQR (ppm ×10) | |||||
| Same day | 5 | −0.33 (−0.49, −0.16) P<0.001 |
−0.28 (−0.45, −0.11) P=0.001 |
|||
| 1 week average | 4 | −0.41 (−0.62, −0.21) P<0.001 |
−0.36 (−0.58, −0.14) P=0.002 |
|||
| 4 month average | 3 | −0.42 (−0.68, −0.15) P=0.002 |
||||
| 4 month average excluding same day | 3 | −0.29 (−0.56, −0.01) P=0.043 |
||||
| 4 month average excluding 1 week | 3 | −0.20 (−0.4, 0.08) P=0.17 |
||||
FEV1: forced expiratory volume in 1 second, IQR: interquartile range, ppm: parts per million, CI: confidence interval