Different effects of urban and rural environments in the respiratory status of Greek schoolchildren.

We hypothesized that asthma symptoms and lung function of schoolchildren living in Athens urban area are adversely affected as compared to others living in a rural environment, over a period of 8 years. We recruited 478 and 342 children aged 8-10 years living within a short radius around the urban and rural area monitoring stations, respectively. Respiratory health was assessed by a parent-completed questionnaire in three phases: 1995-1996 (phase-1), 1999-2000 (phase-2), 2003-2004 (phase-3) and by spirometry in phases-1 and 2. Reported asthma and wheeze did not differ in the two areas, whereas cough was more prevalent in the urban area in phase-1. Children from the rural environment had lower levels of percent-predicted forced vital capacity (FVC%) in phase-1 and higher of percent-predicted-forced expiratory flow at mid-FVC (FEF(50)%) in both phases. Independent associations were detected between FVC% as-well-as FEF(50)% and residential area. High FVC% was associated with outdoor systemic athletic activities; there was lower FVC% growth in the urban versus the rural area. Nitrogen dioxide and sulfur dioxide were higher in the urban area, whereas ozone concentrations differed less between the two areas. These results suggest that long-term exposure to urban environment is associated with sub-clinical airway narrowing and slower rate of FVC growth.