Table 1 Patient characteristics
Baseline characteristics | N = 4978 |
|---|---|
Male, n/N (%) | 3959/4978 (79.5) |
Age (years), mean (SD) | 66.2 (8.9) |
BMI (kg/m2), mean (SD) | 23.0 (3.6) |
Region of residence, n/N (%) | Â |
 North | 1005/4978 (20.2) |
 Northeast | 623/4978 (12.5) |
 East | 1248/4978 (25.1) |
 South central | 904/4978 (18.2) |
 Southwest | 596/4978 (12.0) |
 Northwest | 602/4978 (12.1) |
Residence area, n/N (%) | Â |
 Urban | 2735/4972 (55.0) |
 Rural | 2237/4972 (45.0) |
Highest education, n/N (%) | Â |
 Illiterate | 165/4976 (3.3) |
 Primary school | 1800/4976 (36.2) |
 Secondary school | 1665/4976 (33.5) |
 High/technical school | 779/4976 (15.7) |
 University/college | 556/4976 (11.2) |
 Graduate and above | 11/4976 (0.2) |
Annual per-capita household income (USD),a n/N (%) | Â |
 < 3021 | 1260/4978 (25.3) |
 3021–22 659 | 3376/4978 (67.8) |
 22 659–45 317 | 278/4978 (5.6) |
 45 317–75 528 | 35/4978 (0.7) |
 > 75 528 | 29/4978 (0.6) |
Occupation, n/N (%) | Â |
 White collar worker | 379/4978 (7.6) |
 Blue collar worker | 1685/4978 (33.8) |
 Government officer | 139/4978 (2.8) |
 Unemployed | 1233/4978 (24.8) |
 Retired | 2047/4978 (41.1) |
Smoking status, n/N (%) | Â |
 Non-smoker | 1280/4978 (25.7) |
 Current smoker | 1142/4978 (22.9) |
 Former smoker | 2556/4978 (51.3) |
Passive smoker | 1409/4975 (28.3) |
Pack-years,b mean (SD) | 42.1 (24.1) |
Exposure to noxious particles or gases, n/N (%) | Â |
 No exposure | 3397/4978 (68.2) |
 Dust | 996/4978 (20.0) |
 Harmful gas | 404/4978 (8.1) |
 Biofuels | 564/4978 (11.3) |
 Other noxious substances | 73/4978 (1.5) |
A family history of respiratory disease, c n/N (%) | 1715/4978 (34.5) |