Diverging prevalences and different risk factors for childhood asthma and eczema: a cross-sectional study

Objective: To compare the prevalences of and risk factors for asthma, wheeze, hay fever and eczema in primary schoolchildren in Aberdeen in 2014. Design: Cross-sectional survey. Setting: Primary schools in Aberdeen, North-East Scotland. Participants: Children in Scottish school years primary 1-7 were handed a questionnaire by their class teacher to be completed by their parents and returned to the researchers by post or online. Main outcome measures: Lifetime history of asthma, eczema and hay fever, and recent history of wheeze. Results: 41 schools agreed to participate (87%). 11 249 questionnaires were distributed and 3935 returned (35%). A parent-reported lifetime history of asthma, eczema and hay fever was present in 14%, 30% and 24% of children, respectively. The odds of lifetime asthma increased with age (OR 1.1 per year, 95% CI 1.1 to 1.2), male sex (OR 1.89, 95% CI 1.4 to 2.3), parental smoking (OR 1.7, 95% CI 1.2 to 2.3) and eczema (OR 6.6, 95% CI 5.2 to 8.4). Prevalence of recent wheeze was also reported to be 14% and was positively associated with male sex, parental smoking and eczema. In contrast, parental eczema was the only identified predictor of childhood eczema risk. Conclusions: The lifetime prevalence of asthma in primary schoolchildren was 14% in this survey, approximately half the prevalence of eczema. We report diverging prevalences in relation to previous studies in our locality, and different risk factors for asthma and eczema. These findings suggest that asthma and eczema are unlikely to have a common origin.