['A relevant relationship exists between the upper and lower airway, indicating the concept of a unified airway. This study aimed to evaluate whether rhinitis has an association with asthma in children.', 'A cross-sectional nationwide survey  was performed among children 6-7, 13-14, and 16-17 years old, using the International Study of Asthma and Allergies in Children (ISAAC) questionnaire in Japan. According to the responses to the ISAAC core questions, a child who had experienced nasal symptoms in the past  12 months in the absence of a cold was defined as having current rhinitis.', 'After excluding 11,475 children because of incomplete data, 136,506 children were analyzed. Even after adjusting for demographics, sex, and obesity, children with current rhinitis were more  likely to have asthma (adjusted odds ratio [OR], 3.10 [95% CI, 2.92-3.30] in children aged 6-7 years; OR, 3.76 [95% CI, 3.45-4.10] in children aged 13-14 years; and OR, 3.59 [95% CI, 3.33-3.88] in children aged 16-17 years). Children whose daily activities  were more impaired by rhinitis symptoms had a significantly higher prevalence of severe asthma. The adjusted ORs for severe asthma among asthmatic children whose daily activities were severely impaired by rhinitis symptoms were 3.66 (95% CI, 2.29-5.85) in children aged 6-7 years,  2.55 (95% CI, 1.64-3.96) in children aged 13-14 years, and 1.87 (95% CI, 1.24-2.82) in children aged 16-17 years compared with asthmatic children whose daily activities were not impaired at all.'] Does rhinitis have an association with asthma in school children?