Atopy prevalence and spirometric performance in asymptomatic schoolchildren exposed to air pollution

The association between respiratory disease and high levels of air pollution is well known. The most common risk factors associated with lung function decrease are air-borne particulates, ozone (O3), nitrogen dioxide (NO2) and sulphur dioxide (SO2). The aim of our study was to evaluate any difference in the prevalence of atopy and any possible early impairment in lung function in two groups of children exposed to different levels of air pollution. We studied 220 children in two cities in northern Italy: Milan (107 children), considered a metropolitan area with a high level of air pollution, and Erba (113 children), a small town, close to Lake Como, considered a rural area with a low level of air pollution. All subjects underwent respiratory function tests and skin-prick tests for the main inhalatory allergens. Parents were requested to fill in a questionnaire about parents' smoking habits and subjective evaluation of local motor traffic intensity. Aerobiological surveys showed a significantly higher grass pollen concentration in Erba than in Milan in the study year and in the three previous years. Schoolchildren in Milan and Erba showed similar pulmonary function results, except for forced expiratory flow at 75% of forced vital capacity (FEF75) values that, while within the range of normality, were significantly lower in Milan than in Erba. A high incidence of atopy was evident in both groups: 45% among the children living in Erba and 35% among those in Milan; skin-prick-test positivity for grass-pollen was statistically more frequent in Erba than in Milan. No evidence of a link between atopy and FEF75 reduction emerged, nor between FEF75 reduction and exposure to passive smoke. The association between FEF75 reduction and chronic high levels of air pollution is appealing, but further confirmation studies are necessary.