Table 8. Trends of asthma attacks in three areas [n (%)].
| Group | n | Exacerbation | Unchanged | Relief | No attack within one year | No attack after two years | Attack after one or more years |
|---|---|---|---|---|---|---|---|
| Urban area | 551 | 33 (6.0)a | 90 (16.3)b | 202 (36.7)a | 83 (15.1) | 118 (21.4) | 25 (4.5)a |
| Suburban area | 150 | 14 (9.3) | 30 (20.0) | 41 (27.3) | 21 (14.0) | 33 (22.0) | 11 (7.3) |
| Rural area | 142 | 17 (12.0) | 40 (28.2) | 37 (26.1) | 14 (9.9) | 20 (14.1) | 14 (9.9) |
| χ2 value | 6.55 | 10.41 | 8.57 | 2.54 | 4.08 | 6.37 | |
| P value | <0.05 | <0.01 | <0.05 | >0.05 | >0.05 | >0.05 |
a, P<0.05 compared with the suburban area and rural area; b, P<0.05 compared with the rural area.