Effect of urban vehicular traffic pollution on respiratory symptoms and pulmonary function in schoolchildren

Our aim was to evaluate the relationship between pollution from urban traffic on respiratory symptoms and function in adolescents. In 2005-2006 we performed a survey on 2150 schoolchildren (10-17 yrs) from 16 junior high schools in the city of Palermo, Italy. Subjects fulfilled an ISAAC questionnaire and underwent spirometry and skin tests. The geographic location of each residence was geo-coded by Geographic Information System. A vehicular traffic model computed the daily average traffic of 2561 road segments in the city and was used for estimating the amount of traffic close to each dwelling. We identified 3 areas with progressively increasing traffic: A (in the West side close to the hills around the city - 14.8% of subjects); B (central - 53.7%); and C (the outskirts in the North and South of Area B - 31.5%). Prevalence of respiratory conditions was: wheeze ever (WE), 15.8% in Area A, 22.1% in Area B, and 23.3% in Area C (p=0.02); asthma ever (AE), 8.1%, 12.4%, and 13.0%, respectively (p=0.068); impaired lung function (ILF) was present in 1.7% of subjects, in 4.1%, and in 5.2%, respectively (p=0.037). In a logistic regression model, Odds ratios (OR) with 95% confidence intervals (CI) were calculated with Area A as reference and corrected for confouders: Area B was significant risk factor for WE (OR 1.66, IC 1.17-2.36), AE (OR 1.83, IC 1.15-2.91), and ILF (OR 2.71, IC 1.06-6.89). The corresponding OR for Area C were 1.66 (IC 1.16-2.40), 1.72 (IC 1.06-2.80), and 3.42 (IC 1.32-8.84), respectively. Our results point out that children exposed to increased levels of urban vehicular traffic near the house of residence are at higher risk for asthma and impaired lung function.