Number of participants included in analysis stratified by smoking status and pulmonary function impairment, proportion who died during the follow up period, and proportion of deaths with either COPD listed as the underlying cause of death (UCD) or as any cause of death
| N | Deaths | Proportion of participants who died (%) | Proportion who died with COPD as UCD (%) | Proportion who died with any mention of COPD (%) | |
|---|---|---|---|---|---|
| *Severe COPD = forced expiratory volume in 1 second (FEV1)/forced vital capacity (FVC) <0.70 and FEV1 <50% predicted; moderate COPD=FEV1/FVC <0.70 and FEV1 ⩾50–<80% predicted; mild COPD=FEV1/FVC <0.70 and FEV1 ⩾80%; symptoms only=presence of respiratory symptoms in the absence of any lung function abnormality; restrictive lung disease=FEV1/FVC ⩾0.70 and FVC <80% predicted. | |||||
| From the First National Health and Nutrition Examination Survey 1971–5 and follow up to 1992. | |||||
| Current smokers | |||||
| Severe COPD* | 48 | 37 | 77.1 | 29.7 | 51.4 |
| Moderate COPD | 247 | 116 | 47.0 | 5.2 | 16.4 |
| Mild COPD | 213 | 85 | 39.9 | 2.4 | 7.1 |
| Respiratory symptoms only | 494 | 90 | 18.2 | 2.2 | 8.9 |
| Restrictive lung disease | 224 | 83 | 37.1 | 4.8 | 9.6 |
| No lung disease | 1097 | 169 | 15.4 | 0.6 | 2.4 |
| Total | 2323 | 580 | 25.0 | 4.5 | 11.0 |
| Former smokers | |||||
| Severe COPD | 24 | 21 | 87.5 | 19 | 57.1 |
| Moderate COPD | 81 | 39 | 48.1 | 5.1 | 25.6 |
| Mild COPD | 96 | 30 | 31.3 | 0 | 0 |
| Respiratory symptoms only | 175 | 40 | 22.9 | 0 | 5.0 |
| Restrictive lung disease | 82 | 38 | 46.3 | 5.3 | 7.9 |
| No lung disease | 652 | 122 | 18.7 | 0.8 | 2.5 |
| Total | 1110 | 290 | 26.1 | 3.1 | 10.3 |
| Never smokers | |||||
| Severe COPD | 20 | 7 | 35.0 | 0 | 0 |
| Moderate COPD | 64 | 25 | 39.1 | 0 | 12.0 |
| Mild COPD | 130 | 42 | 32.3 | 0 | 0 |
| Respiratory symptoms only | 223 | 43 | 19.3 | 0 | 0 |
| Restrictive lung disease | 205 | 75 | 36.6 | 0 | 4.0 |
| No lung disease | 1467 | 239 | 16.3 | 0.4 | 2.1 |
| Total | 2109 | 431 | 20.4 | 0.2 | 2.6 |
| All subjects | |||||
| Severe COPD | 92 | 65 | 70.7 | 23.1 | 47.7 |
| Moderate COPD | 392 | 180 | 45.9 | 4.4 | 17.8 |
| Mild COPD | 439 | 157 | 35.8 | 1.3 | 3.8 |
| Respiratory symptoms only | 892 | 173 | 19.4 | 1.2 | 5.8 |
| Restrictive lung disease | 511 | 196 | 38.4 | 3.1 | 7.1 |
| No lung disease | 3216 | 530 | 16.5 | 0.6 | 2.3 |
| Total | 5542 | 1301 | 23.5 | 2.8 | 8.1 |