Increase in the prevalence of rhinitis among Danish children from 1986 to 2001.

In recent decades, there has been a worldwide increase in the prevalence of atopic diseases. The aim of this study was to investigate whether there has been a change in the prevalence of rhinitis among children in Denmark from 1986 to 2001. We compared data from two random population-based samples of Danish children, aged 7-17 yr, who were examined in 1986 (n = 527) and 2001 (n = 480) using similar designs. Symptoms of rhinitis, skin test reactivity, and bronchial responsiveness to inhaled histamine were assessed. The prevalence of rhinitis increased from 11.8% in 1986 to 23.3% in 2001 (p < 0.001). The increase was most pronounced among subjects who suffered from non-allergic rhinitis (p < 0.001), and among subjects with severe symptoms (p < 0.001). The prevalence of asymptomatic positive skin prick test (SPT) decreased substantially (p < 0.001). A history of asthma and parental atopic disease were strong predictors of non-allergic rhinitis, whereas a history of asthma, parental atopic disease, bronchial hyperresponsiveness, eczema, and age at examination were statistically significant predictors of allergic rhinitis. The prevalence of non-allergic rhinitis among Danish children has increased substantially from 1986 to 2001. Furthermore, in general more severe symptoms of rhinitis were observed in 2001 compared with 1986. These results underline the importance of using objective measurements such as skin test reactivity when estimating time trends in the prevalence of allergic airways disease, as clinical interviews alone can be misleading.