| Overall | Men | Women | |||
---|---|---|---|---|---|---|
Cases/total (n/N) | Prevalence of COPD (95% CI) | Cases/total (n/N) | Prevalence of COPD (95% CI) | Cases/total (n/N) | Prevalence of COPD (95% CI) | |
Residence | ||||||
 Urban | 156/1668 | 10.1 (6.4, 15.6) | 116/770 | 15.3 (9.3, 24.4) | 40/898 | 5.2 (2.5, 10.4) |
 Rural | 116/1102 | 9.4 (6.1, 14.2) | 94/592 | 13.8 (8.3, 22.2) | 22/510 | 5.3 (3.7, 7.5) |
 P value |  | 0.790 |  | 0.755 |  | 0.905 |
Educational level | ||||||
 Primary school or lower | 177/1690 | 11.0 (9.1, 13.3) | 126/668 | 19.8 (16.5, 23.5) | 51/1022 | 6.3 (3.7, 10.5) |
 Secondary school | 69/774 | 7.9 (5.8, 10.6) | 62/497 | 11.1 (8.6, 14.2) | 7/277 | 1.9 (0.5, 6.6) |
 Higher or further education | 25/305 | 8.0 (5.2, 12.1) | 21/196 | 9.8 (6.8, 14.1) | 4/109 | 4.1 (1.3, 12.0) |
 P value for trend |  | 0.030 |  | 0.001 |  | 0.075 |
Smoking status | ||||||
 Never smoker | 92/1758 | 5.6 (3.8, 8.3) | 34/386 | 7.9 (6.0, 10.3) | 58/1372 | 5.0 (2.8, 9.0) |
 Former smoker | 41/231 | 13.0 (2.9, 42.2) | 41/219 | 13.7 (2.9, 45.3) | 0/12 | 0 |
 Current smoker | 138/780 | 18.1 (11.7, 26.9) | 134/756 | 18.1 (11.4, 27.4) | 4/24 | 17.8 (5.9, 42.8) |
 P value |  | 0.037 |  | 0.230 |  | 0.184 |
Smoking exposure (pack-years) | ||||||
 Pack-years = 0 | 92/1754 | 5.6 (3.8, 8.3) | 34/385 | 7.9 (6.0,10.3) | 58/1369 | 5.0 (2.8,9.0) |
 0 < pack-years< 15 | 31/269 | 12.6 (6.4,23.5) | 30/251 | 13.1 (6.2–25.5) | 1/18 | 6.2 (0.5,48.8) |
 15 ≤ pack-years< 30 | 45/297 | 10.9 (4.7,23.3) | 45/292 | 11.0 (4.7–23.6) | 0/5 | 0 |
 Pack-years≥30 | 97/398 | 26.1 (18.1,36.0) | 94/389 | 25.7 (18.5,34.6) | 3/9 | 38.6 (7.3,83.4) |
 P value for trend |  | 0.001 |  | < 0.001 |  | 0.116 |
Hospital admission for severe pulmonary disease in childhood | ||||||
 Yes | 3/53 | 4.0 (0.6, 23.3) | 2/26 | 5.3 (0.2, 59.8) | 1/27 | 3.2 (0.3, 29.8) |
 No | 268/2716 | 9.9 (8.4, 11.5) | 207/1335 | 14.8 (13.0, 16.8) | 61/1381 | 5.3 (3.1, 8.8) |
 P value |  | 0.189 |  | 0.333 |  | 0.552 |
Indoor exposure to biomass for cooking or heating | ||||||
 Yes | 110/961 | 11.0 (9.5, 12.7) | 90/489 | 18.7 (15.9, 21.8) | 20/472 | 5.0 (3.5, 7.1) |
 No | 161/1808 | 8.9 (6.7, 11.6) | 119/872 | 12.2 (10.5, 14.0) | 42/936 | 5.4 (2.5, 11.4) |
 P value |  | 0.090 |  | 0.007 |  | 0.739 |
Indoor exposure to coal for cooking or heating | ||||||
 Yes | 58/518 | 11.5 (9.8, 13.4) | 49/250 | 19.3 (16.9, 21.9) | 9/268 | 4.2 (1.8, 9.5) |
 No | 213/2251 | 9.0 (7.1, 11.5) | 160/1111 | 12.7 (10.8, 14.9) | 53/1140 | 5.6 (3.2, 9.9) |
 P value |  | 0.075 |  | 0.006 |  | 0.352 |
Exposure to dust or chemicals in the workplace | ||||||
 Yes | 120/1152 | 9.6 (7.5, 12.3) | 101/640 | 14.5 (11.4, 18.1) | 19/512 | 4.9 (2.7, 8.7) |
 No | 151/1617 | 9.9 (7.4, 13.1) | 108/721 | 14.7 (11.8, 18.3) | 43/896 | 5.5 (2.9, 10.2) |
 P value |  | 0.850 |  | 0.873 |  | 0.606 |
Body-mass index (kg/m2) | ||||||
 < 18.5 | 6/42 | 9.5 (1.8, 37.9) | 5/23 | 17.8 (5.9, 43.1) | 1/19 | 2.7 (0.1, 44.9) |
 18.5–23.9 | 137/1173 | 12.4 (7.4, 19.9) | 114/602 | 20.0 (12.5, 30.4) | 23/571 | 5.1 (2.1, 12.0) |
 24.0–27.9 | 99/1114 | 8.9 (7.2, 10.9) | 70/547 | 10.9 (8.3, 14.2) | 29/567 | 6.9 (3.6, 12.6) |
 ≥28.0 | 30/441 | 6.3 (5.4, 7.4) | 21/190 | 11.5 (7.5, 17.1) | 9/251 | 2.5 (1.0, 5.9) |
 P value for trend |  | 0.094 |  | 0.044 |  | 0.135 |