|
Baseline factors
|
Sputum + n = 3139
|
Sputum − n = 6665
|
p value
|
OR (95% CI) for sputum production
|
p value
|
|---|
|
Age, yeara
|
54.0 ± 13.9
|
53.4 ± 13.2
|
0.04
|
1.10 (1.06–1.14)
|
< 0.0001
|
|
Male sex, %
|
47.0
|
26.1
|
< 0.0001
|
2.34 (2.07–2.65)
|
< 0.0001
|
|
BMI, kg/m2
|
22.5 ± 3.4
|
22.2 ± 3.2
|
< 0.0001
|
1.00 (0.98–1.01)
|
0.87
|
|
Smoking history (ex or current), %
|
47.6
|
29.0
|
< 0.0001
|
1.49 (1.33–1.68)
|
< 0.0001
|
|
COPD, %
|
2.2
|
0.6
|
< 0.0001
|
2.21 (1.44–3.38)
|
0.0003
|
|
Asthma, %
|
6.3
|
3.1
|
< 0.0001
|
1.53 (1.22–1.90)
|
0.0002
|
|
Prolonged cough, %
|
16.6
|
7.6
|
< 0.0001
|
2.31 (2.00–2.66)
|
< 0.0001
|
|
Allergic rhinitis, %
|
37.7
|
34.0
|
0.0003
|
1.02 (0.92–1.12)
|
0.76
|
|
Sinusitis, %
|
14.1
|
8.3
|
< 0.0001
|
1.39 (1.20–1.60)
|
< 0.0001
|
|
Post-nasal drip, %
|
32.3
|
15.9
|
< 0.0001
|
2.40 (2.15–2.68)
|
< 0.0001
|
|
Diabetes mellitus, %
|
7.0
|
4.4
|
< 0.0001
|
1.25 (1.02–1.52)
|
0.03
|
|
FSSG score ≥ 8, %
|
32.7
|
18.0
|
< 0.0001
|
1.92 (1.73–2.13)
|
< 0.0001
|
|
Stress, %
|
74.3
|
71.1
|
0.0007
|
1.30 (1.17–1.45)
|
< 0.0001
|
- OR odds ratio, CI confidence interval, BMI body mass index, COPD chronic obstructive pulmonary disease, FSSG Frequency Scale for Symptoms of Gastroesophageal Reflux Disease
- aAge per 10-year increase
- For multivariable analysis
