TABLE II.
Covariate | Association P-value
|
|||
---|---|---|---|---|
PC1 | PC2 | PC3 | PC4 | |
Discrete variablesa | ||||
Race | 1.61 × 10−8 | 0.03 | 0.40 | 0.60 |
Gender | 0.24 | 0.11 | 0.04 | 0.48 |
Clinic | 1.1 × 10−6 | 2 × 10−16 | 0.07 | 0.02 |
Active smoking history | 0.007 | 0.61 | 0.08 | 0.88 |
Asthma medication use | ||||
Inhaled corticosteroids | 0.71 | 0.05 | 0.77 | 0.27 |
Long-acting beta agonists | 0.50 | 0.98 | 0.60 | 0.64 |
Continuous variables | ||||
Age | 0.96 | 0.62 | 0.76 | 0.88 |
Height | 0.21 | 0.97 | 0.32 | 0.32 |
Pre-bronchodilator FEV1 | 0.71 | 0.51 | 0.07 | 0.03 |
Immunoglobulin E (IgE level) | 0.22 | 0.74 | 0.57 | 0.01 |
FEV1, forced expiratory volume in one second; IgE, immunoglobulin E.
Discrete variables tested by two-sided t-test or ANOVA. Continuous variables tested by Spearman’s correlation.