A lower thirst sensitivity frequently characterizes children and adolescents. The daily water intake can be frequently insufficient for the homeostasis and the integrity of their airway epithelium. Little is known about the real-life relationship between dehydration and coughing in young students with asthma. The aim was to investigate the effect of dehydration on coughing in asthmatic students aged ≤16 years. A validated questionnaire aimed to investigate their respiratory history and cough incidence was used. Urine samples were also collected for assessing osmolality. Wilcoxon test, the Pearson Chi Square and the Fisher Exact Test were used; p < 0.05 was assumed as significant. Valid data were obtained from 305 healthy and 56 asthmatic students. Mean urine osmolality was significantly higher in asthmatic than in healthy students (1012 ± 197.7 vs. 863.0 ± 223.0 mOsm/kg, respectively; p < 0.001), particularly in symptomatic asthmatic students (1025 ± 191.6 mOsm/kg, p < 0.01). Both the incidence and duration of coughing episodes were directly related to the degree of urine osmolality (both p < 0.001). Dehydration affects the prevalence and the duration of a cough in asthmatic students aged ≤16 years. Adequate daily water intake should be stimulated in these subjects in order to contain their basic cough attitude.
Keywords: adolescents; asthma; cough; dehydration; urine osmolality; water.