FEV1 % predicted | FVC % predicted | FEV1/FVC | Airflow limitation | |||||||
FEV1/FVC <70% | FEV1/FVC <LLN | |||||||||
Adjusted coefficient (95% CI) | p-value | Adjusted coefficient (95% CI) | p-value | Adjusted coefficient (95% CI) | p-value | Adjusted OR (95% CI) | p-value | Adjusted OR (95% CI) | p-value | |
All subjects# (n=418) | −1.50 (−3.28, 0.29) | 0.100 | −0.58 (−2.25, 1.09) | 0.499 | −0.83 (−1.75, 0.08) | 0.074 | 1.26 (0.93, 1.73) | 0.140 | 1.36 (1.00, 1.85) | 0.053 |
Never-smokers¶ (n=176) | 2.19 (−0.63, 5.00) | 0.127 | 2.66 (−0.18, 5.50) | 0.067 | −0.24 (−1.62, 1.13) | 0.727 | 1.02 (0.49, 2.11) | 0.958 | 1.20 (0.58, 2.47) | 0.618 |
Ever-smokers# (n=242) | −3.36 (−5.65, −1.07) | 0.004 | −2.40 (−4.47, −0.33) | 0.023 | −1.33 (−2.49, −0.18) | 0.024 | 1.31 (0.93, 1.84) | 0.124 | 1.40 (1.01, 1.96) | 0.046 |
Former smokers+ (n=123) | −7.09 (−10.66, −3.51) | <0.001 | −5.50 (−8.87, −2.13) | 0.001 | −2.31 (−4.04, −0.58) | 0.009 | 1.91 (1.14, 3.19) | 0.014 | 2.12 (1.29, 3.47) | 0.003 |
Current smokers+ (n=119) | 0.21 (−2.51, 2.93) | 0.880 | 0.92 (−1.45, 3.30) | 0.446 | −0.08 (−1.67, 1.51) | 0.919 | 1.00 (0.59, 1.70) | 0.991 | 1.15 (0.71, 1.85) | 0.571 |
Body mass index (BMI) information was missing for nine participants (two never-, three former and four current smokers). Airflow limitation was present among 67 and 56 participants when defined by forced expiratory volume in 1 s (FEV1)/forced vital capacity (FVC) <70% and below the lower limit of normal (LLN), respectively. #: models adjusted for sex, age, BMI, smoking status and pack-years; ¶: models adjusted for sex, age and BMI; +: models adjusted for sex, age, BMI and pack-years.