Table 9 Breath CO and COHb levels based on the presence or absence of respiratory symptoms, n = 402

Presence of at least one cough-related symptom

5.18 ± 4.79

(96)

3.75 ± 3.66

(307)

0.37–2.47

2.67

0.008^*

1.46 ± 0.77

(96)

1.23 ± 0.59

(307)

0.06–0.40

2.72

0.007^*

Presence of at least one phlegm-related symptom

4.68 ± 4.39

(171)

3.67 ± 3.65

(231)

0.20–1.82

2.45

0.015^*

1.38 ± 0.70

(171)

1.22 ± 0.58

(231)

0.03–0.29

2.49

0.013^*

Presence of at least one wheezing-related symptom

5.22 ± 4.39

(118)

3.63 ± 3.74

(285)

0.68–2.50

3.45

0.001^*

1.47 ± 0.70

(118)

1.21 ± 0.60

(285)

0.11–0.40

3.49

0.001^*

Presence of at least one dyspnea-related symptom

4.92 ± 4.48

(119)

3.75 ± 3.74

(284)

0.25–2.10

2.52

0.013^*

1.42 ± 0.72

(119)

1.23 ± 0.60

(284)

0.40–0.34

2.51

0.013^*