Several studies on the prevalence of allergic conditions have identified that allergic conditions are on the increase worldwide. The aim of this study was to study the effect of classroom humidity and temperature levels on schoolchildren in Malta. Our cohort included 191 children. Standardised ISAAC health questionnaires were answered by the children’s parents. Lung function tests, acoustic rhinometry, exhaled NO, exhaled CO and nasal lavage were performed on the participating children. School building characteristics were also studied. A significant association was noted between a high relative humidity exposure and nasal cross-sectional areas (p=0.003), and doctor diagnosed allergic rhinitis (p=0.002), indicating the presence of allergic rhinitis, as was increased indoor temperature (p=0.003). Increased indoor temperature was also associated with increased exhaled nitric oxide (FeNO) (p<0.001) indicating uncontrolled asthma. In conclusion, increased classroom temperatures and humidity, both linked to decreased classroom ventilation, were associated with increased incidence of allergic conditions in schoolchildren in Malta. These results emphasize the important need for the introduction of climate control and dehumidifying systems in our schools with the aim of decreasing the prevalence and severity of such conditions in this cohort of patients.peer-reviewe
