Characteristics of study populations in urban Liwang and rural Yunyan*
| Urban Liwang(n = 1818) | Rural Yunyan(n = 1468) | Total(n = 3286) | p Value (Liwang vs Yunyan) | |
|---|---|---|---|---|
| ETS, environmental tobacco smoke; BMI, body mass index; LPG, liquid petroleum gas. | ||||
| *Data shown as number (%) of observations. | ||||
| †Environmental tobacco smoke exposure (duration of passive smoking over 5 years). | ||||
| ‡Chronic bronchitis, emphysema, bronchial asthma or COPD in family members in the households. | ||||
| §Defined by family income. | ||||
| ¶Crop residues, wood, etc. | ||||
| Sex | 0.156 | |||
| Men | 730 (40.2) | 640 (43.6) | 1370 (41.7) | |
| Women | 1088 (59.8) | 828 (56.4) | 1916 (58.3) | |
| Age group (years) | <0.001 | |||
| 40–49 | 529 (29.1) | 600 (40.9) | 1129 (34.4) | |
| 50–59 | 381 (21.0) | 372 (25.3) | 753 (22.9) | |
| 60–69 | 525 (28.9) | 344 (23.4) | 869 (26.4) | |
| ⩾70 | 383 (21.1) | 152 (10.4) | 535 (16.3) | |
| Education (years) | <0.001 | |||
| 0 | 175 (9.6) | 870 (59.3) | 1045 (31.8) | |
| 1–6 | 585 (32.2) | 433 (29.5) | 1018 (31.0) | |
| ⩾7 | 1058 (58.2) | 165 (11.2) | 1223 (37.2) | |
| Smoking status | <0.001 | |||
| Non-smokers without ETS† | 626 (34.4) | 268 (18.3) | 894 (27.2) | |
| Non-smokers with ETS | 553 (30.4) | 636 (43.3) | 1189 (36.2) | |
| Smokers <15 pack-years | 191 (10.5) | 132 (9.0) | 323 (9.8) | |
| Smokers ⩾15 pack-years | 448 (24.6) | 432 (29.4) | 880 (26.8) | |
| Occupational exposure to dust | <0.001 | |||
| Yes | 433 (23.8) | 1413 (96.3) | 1846 (56.2) | |
| No | 1385 (76.2) | 55 (3.7) | 1440 (43.8) | |
| Respiratory disease in family‡ | 0.001 | |||
| Yes | 354 (19.5) | 367 (25.0) | 721 (21.9) | |
| No | 1464 (80.5) | 1101 (75.0) | 2565 (78.1) | |
| Cough in childhood | <0.001 | |||
| Often/sometimes | 154 (8.5) | 23 (1.6) | 177 (5.4) | |
| Seldom | 1664 (91.5) | 1445 (98.4) | 3109 (94.6) | |
| BMI (kg/m2) | <0.001 | |||
| <18.5 | 166 (9.1) | 53 (3.6) | 219 (6.7) | |
| 18.5–23.9 | 1008 (55.5) | 1022 (69.6) | 2030 (61.8) | |
| ⩾24.0 | 644 (35.4) | 393 (26.8) | 1037 (31.6) | |
| Life quality§ | <0.001 | |||
| Poor | 92 (5.1) | 377 (25.7) | 469 (14.3) | |
| General | 1492 (82.1) | 1048 (71.4) | 2540 (77.3) | |
| Good | 234 (12.9) | 43 (2.9) | 277 (8.4) | |
| Fuel type | <0.001 | |||
| LPG | 1793 (98.6) | 15 (1.0) | 1808 (55.0) | |
| Coal | 12 (0.7) | 160 (10.9) | 172 (5.2) | |
| Biomass¶ | 13 (0.7) | 1293 (88.1) | 1306 (39.8) | |
| Local exhaust ventilation in kitchen | <0.001 | |||
| Yes | 1610 (88.6) | 10 (0.7) | 1620 (49.3) | |
| No | 208 (11.4) | 1458 (99.3) | 1666 (50.7) | |
| COPD | 0.004 | |||
| Yes | 134 (7.4) | 176 (12.0) | 310 (9.4) | |
| No | 1684 (92.6) | 1292 (88.0) | 2976 (90.6) | |