Prevalence of COPD (FEV1/FVC <0.7) defined before and after bronchodilatation in a general adult population in 1996–7 by sex, age, body mass index, smoking habits, pack years, occupational exposure, and residential area
| N | Pre-bronchodilator prevalent cases | Post-bronchodilator prevalent cases | Percentage reduction in prevalence after bronchodilatation relative to before | Estimated post-bronchodilator prevalence (95% CI) | |
|---|---|---|---|---|---|
| Sex | |||||
| Women | 1129 | 65 | 42 | 35% | 3.7% (2.6 to 4.8) |
| Men | 1106 | 149 | 114 | 23% | 10.3% (8.5 to 12.1) |
| Age (years) | |||||
| 26–44 | 930 | 44 | 22 | 50% | 2.4% (1.4 to 3.3) |
| 45–59 | 700 | 41 | 29 | 29% | 4.1% (2.7 to 5.6) |
| 60–74 | 465 | 88 | 71 | 19% | 15.3% (12.0 to 18.6) |
| 75–82 | 140 | 41 | 34 | 17% | 24.3% (17.1 to 31.5) |
| Body mass index (kg/m2) | |||||
| <20 | 112 | 16 | 13 | 19% | 11.6% (5.6 to 17.6) |
| 20–24.9 | 969 | 112 | 75 | 33% | 7.7% (6.1 to 9.4) |
| 25–29.9 | 868 | 69 | 52 | 25% | 6.0% (4.4 to 7.6) |
| >30 | 279 | 17 | 16 | 6% | 5.7% (3.0 to 8.5) |
| Smoking habits | |||||
| Never smokers | 864 | 46 | 22 | 52% | 2.5% (1.5 to 3.6) |
| Ex-smokers | 619 | 75 | 70 | 7% | 11.3% (8.8 to 13.8) |
| Current smokers | 752 | 93 | 64 | 31% | 8.5% (6.5 to 10.5) |
| Pack years | |||||
| 1–9 | 541 | 39 | 26 | 33% | 4.8% (3.0 to 6.6) |
| 10–19 | 408 | 43 | 36 | 16% | 8.8% (6.1 to 11.6) |
| 20+ | 374 | 79 | 65 | 18% | 17.4% (13.5 to 21.2) |
| Educational level | |||||
| Primary | 404 | 70 | 58 | 17% | 14.4% (10.9 to 17.8) |
| Secondary | 1311 | 113 | 80 | 29% | 6.1% (4.8 to 7.4) |
| University | 494 | 27 | 15 | 44% | 3.0% (1.5 to 4.6) |
| Occupational exposure to gas or dust | |||||
| No | 1136 | 81 | 55 | 32% | 4.8% (3.6 to 6.1) |
| Yes | 1049 | 126 | 94 | 25% | 9.0% (7.2 to 10.7) |
| Residential area | |||||
| Rural | 706 | 64 | 45 | 30% | 6.4% (4.6 to 8.2) |
| Urban | 1529 | 150 | 111 | 26% | 7.3% (6.0 to 8.6) |
| Total | 2235 | 214 | 156 | 27% | 7.0% (5.9 to 8.0) |