Table 2.
Baseline characteristics in relation to quartiles of FEV1: Females (n = 7325)
| Overall | Q4 | Q3 | Q2 | Q1 | P value for trend | |
|---|---|---|---|---|---|---|
| FEV1 (L) | 2.63(±0.58) | 3.31(±0.33) | 2.80(±0.08) | 2.46(±0.11) | 1.88(±0.33) | – |
| Number (n) | 7325 | 2027 | 1629 | 1933 | 1736 | – |
| Age (years) | 47.5 (±7.9) | 43.7 (±8.0) | 46.1 (±7.9) | 48.9 (±7.1) | 51.7 (±5.6) | < 0.001 |
| Height (m) | 1.64(±0.06) | 1.67(±0.05) | 1.64(±0.05) | 1.62(±0.05) | 1.61(±0.06) | < 0.001 |
| BMI (kg/m2) | 23.9 (±4.0) | 23.0 (±3.4) | 23.6 (±3.7) | 24.2 (±4.1) | 24.6 (±4.6) | < 0.001 |
| Baseline eGFR (mL/min/1.73m2) | 84.1(±13.6) | 85.6(±13.9) | 84.4(±13.8) | 83.7(±13.2) | 82.5(±13.3) | < 0.001 |
| Current-smokers (%) | 45.6 | 33.1 | 38.1 | 46.8 | 65.9 | < 0.001 |
|
Physical inactivity (%) - Missing data (%) |
43.3 12.3 |
35.7 18.6 |
39.9 15.3 |
45.2 10.1 |
53.2 4.4 |
< 0.001 |
| Systolic BP (mmHg) | 123 (±16) | 120 (±14) | 122 (±15) | 124 (±17) | 126 (±18) | < 0.001 |
| Anti-hypertensive medication (%) | 6.6 | 3.3 | 5.5 | 7.3 | 10.8 | < 0.001 |
| Cholesterol (mmol/L) | 5.66(±1.09) | 5.36 (±1.01) | 5.56(±1.05) | 5.77 (±1.08) | 5.99 (±1.11) | < 0.001 |
| History of CVD | 0.7 | 0.2 | 0.2 | 1.1 | 1.3 | < 0.001 |
| History of diabetes | 2.6 | 1.2 | 1.4 | 3.2 | 4.7 | < 0.001 |
| Social class (%) | – | |||||
| - Low skilled | 45.1 | 37.1 | 42.4 | 49.4 | 52.0 | |
| - High skilled | 45.0 | 55.8 | 48.4 | 49.8 | 34.8 | |
| - Self-employed | 2.9 | 2.8 | 2.8 | 2.8 | 3.1 | |
| - Other | 7.1 | 4.2 | 6.3 | 8.1 | 10.1 |
Q Quartile, FEV1 Forced expiratory volume in 1 s, eGFR Estimated glomerular filtration rate, BMI Body mass index, BP Blood pressure, CVD Cardiovascular disease. Data consist of mean (±standard deviation) unless otherwise stated. Linear by linear association for chi square tests used for p-value for categorical variables, ANOVA test for linearity used for p-values of continuous variables