Table 3.
Likelihood of respiratory symptomsa by lung function category
| %b (95% CI) | Adjusted PRc (95% CI) | ||
|---|---|---|---|
|
Frequent cough |
|
|
|
| Normal lung function |
8.6 (7.1-10.3) |
1.00 |
-- |
| Restrictive impairment |
13.0 (8.9-18.7) |
1.12 |
(0.75-1.66) |
| Mild obstruction |
9.3 (6.4-13.2) |
0.83 |
(0.53-1.29) |
| Moderate–severe obstruction |
24.2 (18.7-30.7) |
1.63 |
(1.20-2.20) |
|
Frequent phlegm |
|
|
|
| Normal lung function |
5.9 (5.2-6.8) |
1.00 |
-- |
| Restrictive impairment |
10.0 (6.4-15.3) |
1.14 |
(0.72-1.81) |
| Mild obstruction |
9.1 (6.0-13.6) |
1.21 |
(0.76-1.93) |
| Moderate–severe obstruction |
19.8 (14.5-26.4) |
1.99 |
(1.31-3.03) |
|
Wheeze |
|
|
|
| Normal lung function |
10.2 (9.0-11.5) |
1.00 |
-- |
| Restrictive impairment |
18.5 (13.7-24.6) |
1.36 |
(0.99-1.87) |
| Mild obstruction |
11.8 (8.7-15.7) |
1.23 |
(0.89-1.71) |
| Moderate–severe obstruction |
31.9 (25.8-38.8) |
2.65 |
(2.04-3.43) |
|
Any respiratory symptoms |
|
|
|
| Normal lung function |
17.1 (15.1-19.3) |
1.00 |
-- |
| Restrictive impairment |
29.0 (23.8-34.8) |
1.32 |
(1.06-1.63) |
| Mild obstruction |
19.9 (15.8-24.8) |
1.06 |
(0.81-1.38) |
| Moderate–severe obstruction | 47.4 (39.9-55.0) | 2.10 | (1.69-2.60) |
a Respiratory symptoms included the following: cough most days (at least 3 months), bring up phlegm most days (at least 3 months), or had wheeze or whistle in chest (in past 12 months).
b Unadjusted.
c Adjusted prevalence ratio (PR) and 95% confidence interval (CI) obtained from multivariable logistic regression that included sex, age, race/ethnicity, education, number of non-respiratory chronic illnesses, smoking status, and BMI as covariates.