Percentage (number) of children with symptoms in the preceding 12 months by age and year of survey
| 1993 | 1995 | 1999 | 2001 | χ2 | p for trend | |
|---|---|---|---|---|---|---|
| Wheeze at age: | ||||||
| 1 | 36.4 (68/187) | 29.6 (32/108) | 35.1 (39/111) | 29.9 (32/107) | 0.789 | 0.37 |
| 2 | 39.1 (79/202) | 30.5 (39/128) | 24.8 (25/101) | 26.6 (25/94) | 6.997 | <0.01 |
| 3 | 30.1 (62/206) | 36.8 (50/136) | 30.4 (35/115) | 30.4 (31/102) | 0.006 | 0.94 |
| 4 | 36.4 (63/173) | 25.6 (40/156) | 27.6 (32/116) | 29.5 (28/95) | 1.708 | 0.19 |
| Cough at age: | ||||||
| 1 | 36.4 (68/187) | 27.0 (30/111) | 33.6 (37/110) | 27.1 (29/107) | 1.846 | 0.17 |
| 2 | 38.9 (79/203) | 31.5 (41/130) | 20.2 (21/104) | 26.6 (25/94) | 8.922 | <0.01 |
| 3 | 38.0 (79/208) | 47.4 (64/135) | 36.0 (41/114) | 35.0 (36/103) | 0.588 | 0.44 |
| 4 | 48.3 (86/178) | 41.4 (65/157) | 38.3 (44/115) | 34.7 (33/95) | 5.410 | 0.02 |