Respiratory symptoms and atopy in Aberdeen schoolchildren: evidence from two surveys 25 years apart.

OBJECTIVE: To estimate changes in the prevalence of respiratory symptoms and the reported diagnoses of asthma, eczema, and hay fever in primary school children in Aberdeen between 1964 and 1989. DESIGN: Determination of incidence prevalence and prevalence from survey data. SETTING: Aberdeen, Scotland. PARTICIPANTS: 2743 primary school children (aged 8-13) from 1964 and 4003 corrected from 1989. MAIN OUTCOME MEASURES: Survey data on whether, according to the parent or guardian, the child wheezed or was troubled with shortness of breath; the number of episodes of breathlessness in the past year; and whether asthma, eczema, or hay fever had ever been diagnosed. RESULTS: Questionnaires were completed by the parents of 2510 children in 1964 and 3403 children in 1989. The prevalence of wheeze rose from 10.4% in 1964 to 19.8% in 1989, and the prevalence of episodes of shortness of breath increased from 5.4% to 10.0%. In both surveys wheeze and shortness of breath were more prevalent in boys than in girls. The reported diagnosis of asthma rose from 4.1% to 10.2%, hay fever from 3.2% to 11.9%, and eczema from 5.3% to 12%. The proportion of boys suffering from eczema rose from 47.7% to 60.0%. Hay fever showed a similar increase, from 49.4% to 60.1%, in boys over the 25 year period. Though the parents of a higher proportion of children with wheeze were aware of the diagnosis of asthma in 1989, because of the increased prevalence of wheeze the absolute number of parents of wheezy children who were not aware of a diagnosis of asthma increased from 7.4% to 9.6% of the population studied. CONCLUSION: The higher diagnosis rate for asthma is due not simply to changes in diagnostic fashion but reflects an increase over the past 25 years in the prevalence of respiratory symptoms, which in turn may reflect a more general change in the prevalence of atopy, the increase in which was particularly noticeable in boys. This increase explains some of the increase in hospital admission rates for children with asthma.