Table 3.
Demographic characteristics and risk factors for COPD in subjects living at low (<1500 m) and high (>1500 m) altitude
| Characteristics | Altitude <1500 m | Altitude >1500 m | p-value |
|---|---|---|---|
| n = 26,896 | n = 3978 | ||
| COPD prevalence (%) | 9.9 | 8.5 | <0.005 |
| Mean FEV1 (Litre, SD) | 2.66 (0,85) | 2.45 (0.78) | 0.010 |
| Mean FVC (Litre, SD) | 3.47 (1.05) | 3.20 (0.90) | <0.001 |
| Mean FEV1/FVC (SD) | 76.8 (8.8) | 76.2 (10.0) | <0.001 |
| Sex – female (%) | 54.9 | 62.1 | <0.001 |
| Age (Mean, SD) | 56.2 (11.3) | 55.1 (11.3) | <0.001 |
| Never-smoker (%) | 48.6 | 56.5 | <0.001 |
| Dusty job (%) | 36.1 | 24.5 | <0.001 |
| Tuberculosis (%)a | 3.5 | 0.4 | <0.001 |
| Education >12 years (%) | 23.6 | 9.5 | <0.001 |
| Prior lung function test, ever (%)b | 28.1 | 4.1 | <0.001 |
| Self-reported diagnosis of COPD (%) | 5.1 | 3.9 | <0.001 |
| Proportion of correct prior diagnosis of COPD (%) | 37.0 | 31.2 | 0.158 |
| Proportion of undiagnosed COPD (%) | 80.8 | 85.8 | 0.029 |
a14, 691 missing values
b5, 598 missing values