|
Linear mixed effect models: CO and FEV1 |
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| Independent variable |
Time interval |
B |
95% CI |
P value |
|
|
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| CO, ppm |
0–1 hour |
3.61 |
2.67–4.54 |
<0.0001 |
| 1–12 hours |
-0.29 |
-0.38 – -0.21 |
<0.0001 |
|
|
|
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| FEV1, L/sec |
0–1 hour |
0.06 |
-0.07–0.20 |
0.38 |
|
The time intervals of the above parameters were selected based on visual inspection of the plots. The slopes of the parameters were estimated using linear mixed effect models [11] by including the variables time (hours), smoking (yes or no) and their interaction. B: regression coefficient for the variable time (for further information see the method section). CO: carbon monoxide; FEV1: Forced Expiratory Volume in 1 second. | ||||
van der Vaart et al. Respiratory Research 2005 6:22 doi:10.1186/1465-9921-6-22 |
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