Table 1 Characteristics of the study population, stratified by SES (n = 22, 878), n (%) or mean ± SD
| Â | Â | Education Level | ||
|---|---|---|---|---|
|  | Total Population | ≤elementary | middle/high | ≥college |
Subjects, n (%) | 22,878 (100) | 8375 (36 · 6) | 10,351 (45 · 2) | 4152 (18 · 2) |
Age, years | 48 · 4 ± 16 · 4 | 58 · 5 ± 13 · 3 | 44 · 9 ± 14 · 6 | 36 · 8 ± 15 · 1 |
Female | 12,195 (53 · 3) | 5048 (60 · 3) | 5339 (51 · 6) | 1808 (43 · 6) |
Smoking | Â | Â | Â | Â |
 Current | 5249 (22 · 9) | 2028 (24 · 2) | 2636 (25 · 5) | 585 (14 · 1) |
 Former | 878 (3 · 8) | 439 (5 · 2) | 349 (3 · 4) | 90 (2 · 2) |
 Never | 16,751 (73 · 2) | 5908 (70 · 5) | 7366 (71 · 2) | 3477 (83 · 7) |
Pack-yearsa | 26 · 3 ± 36 · 6 | 32 · 3 ± 42 · 5 | 23 · 3 ± 31 · 6 | 17 · 9 ± 30 · 0 |
SHS exposed | 17,060 (74 · 6) | 6492 (77 · 5) | 7976 (77 · 1) | 2592 (62 · 4) |
Biomass ever users | 18,214 (79 · 6) | 7799 (93 · 1) | 8056 (77 · 8) | 2359 (56 · 8) |
Low fruit/vegetable | 13,683 (59 · 8) | 5876 (70 · 2) | 5886 (56 · 9) | 1921 (46 · 3) |
Mode of Transport | Â | Â | Â | Â |
 None | 8 (0 · 0) | 6 (0 · 1) | 0 (0 · 0) | 2 (0 · 1) |
 Bus w/o AC | 2950 (12 · 9) | 1157 (13 · 8) | 1323 (12 · 8) | 470 (11 · 3) |
 Bus with AC | 3665 (16 · 0) | 696 (8 · 3) | 2011 (19 · 4) | 958 (23 · 1) |
 Scooter | 2628 (11 · 5) | 691 (8 · 3) | 1554 (15 · 0) | 383 (9 · 2) |
 Taxi | 128 (0 · 6) | 27 (0 · 3) | 70 (0 · 7) | 31 (0 · 8) |
 Company Car | 330 (1 · 4) | 57 (0 · 7) | 189 (1 · 8) | 84 (2 · 0) |
 Private Car | 1916 (8 · 4) | 168 (2 · 0) | 929 (9 · 0) | 819 (19 · 7) |
 Train | 18 (0 · 1) | 0 (0 · 0) | 10 (0 · 1) | 8 (0 · 2) |
 Subway | 138 (0 · 6) | 5 (0 · 1) | 59 (0 · 6) | 74 (1 · 8) |
 Walk | 3219 (14 · 1) | 2246 (26 · 8) | 800 (7 · 7) | 173 (4 · 2) |
 Multiple | 2709 (11 · 8) | 693 (8 · 3) | 1247 (12 · 1) | 769 (18 · 5) |
 Bike | 5169 (22 · 6) | 2629 (31 · 4) | 2159 (20 · 9) | 381 (9 · 2) |
Occupation | Â | Â | Â | Â |
 Farmer | 110 (0.5) | 102 (1.2) | 8 (0.1) | 0 (0.0) |
 Worker | 1405 (6.1) | 689 (8.2) | 696 (6.7) | 20 (0.5) |
 Professional | 5128 (22.4) | 595 (7.1) | 2636 (25.5) | 1897 (45.7) |
 Administrator | 2969 (13.0) | 276 (3.3) | 1688 (16.3) | 1005 (24.2) |
 Services | 1526 (6.7) | 556 (6.6) | 909 (8.8) | 61 (1.5) |
 Household | 368 (1.6) | 206 (2.5) | 145 (1.4) | 17 (0.4) |
 Retired | 9130 (39.9) | 5443 (65.0) | 3129 (30.2) | 558 (13.4) |
 Other | 2242 (9.8) | 508 (6.1) | 1140 (11.0) | 594 (14.3) |
% FEV1 | 97 · 8 ± 16 · 3 | 96 · 1 ± 18 · 6 | 98 · 6 ± 14 · 9 | 99 · 4 ± 14 · 0 |
% FVC | 89 · 3 ± 16 · 1 | 85 · 4 ± 17 · 5 | 90 · 8 ± 14 · 8 | 93 · 5 ± 14 · 4 |