Prevalence of positive answers to questions concerning wheezing, dyspnoea and asthma
| Survey year | |||
| 1974 | 1992 | 1998 | |
| Subject n | 2259 | 1229 | 1139 |
| Q1 Physician diagnosis of asthma or asthmatic bronchitis | 5.0 | 11.6 | 11.0 |
| Q2 Dyspnoea on effort more easily than other children | 0.9 | 2.6 | 4.1 |
| Q3 Parent reported asthmatic attacks (attacks of breathlessness and audible wheezing) | 3.6 | 10.8 | 9.4 |
| Q4 Parent reported asthmatic attacks during the past year | 1.6 | 4.0 | 3.7 |
| Asthma | 5.5 | 12.2 | 12.0 |
Data are presented as per cent of total population
affirmative answer to question 1 or to question 2 and 3
p<0.0001, Chi-squared test
p=ns