Respiratory symptoms in children living near busy roads and their relationship to vehicular traffic: results of an Italian multicenter study (SIDRIA 2)
1 Cancer Epidemiology Unit, AOU San Giovanni Battista Hospital – Center for Cancer Prevention (CPO Piedmont) and University of Turin, Via Santena 7, 10126 Turin, Italy
2 Regional Environmental Protection Agency, Piedmont Region, Via Sabaudia 164, 10095 Grugliasco (Turin), Italy
3 Centre for Public Health Research, Massey University Wellington Campus, PO Box 756 Wellington 6140 NZ
4 Department of Biomedical Sciences and Human Oncology, University of Turin, Via Santena 7, 10126 Turin, Italy
5 Department of Epidemiology, Rome/E Local Health Authority, Via di S. Costanza 53, 00198 Rome, Italy
6 Department of Pediatrics, "Regina Margherita" Children's Hospital, University of Turin, P.zza Polonia 94, 10126 Turin, Italy
7 I Pediatric Clinic, University of Bari, Piazza G. Cesare 11,70124 Bari, Italy
8 Department of Statistics, University of Florence, Viale Morgagni 59, 50134 Florence, Italy
9 Unit of Biostatistics, Istituto per lo Studio e la Prevenzione Oncologica (ISPO), Via San Salvi 12, 50135 Florence, Italy
10 Epidemiology Unit, Local Health Authority, Corso Italia 19, 20122 Milan, Italy
11 Unit of Pneumology and Allergology, Local Health Authority TO-2, Lungo Dora Savona 26, 10152 Turin, Italy
12 Unit of Environmental and Occupational Epidemiology, Istituto per lo Studio e la Prevenzione Oncologica (ISPO), Via San Salvi 12, 50135 Florence, Italy
13 Department of Prevention, Rome/G Local Health Authority – Tivoli Corso Garibaldi 7, 00034 Colleferro (Rome), Italy
14 Unit of Preventive Medicine, Local Health Authority, Via Trento 6, 46100 Mantova, Italy
15 Institute of Respiratory Diseases, University of Siena, Viale Bracci 3, 53100 Siena, Italy
16 Department of Respiratory Physiology, Catholic University of Rome, Largo F.Vito 1, 00168 Rome, Italy
17 CNR Institutes of Biomedicine and Molecular Immunology, Palermo, and of Clinical Physiology, Pisa. Via Ugo La Malfa 153, 90146 Palermo, Italy
Environmental Health 2009, 8:27 doi:10.1186/1476-069X-8-27Published: 18 June 2009
Epidemiological studies have provided evidence that exposure to vehicular traffic increases the prevalence of respiratory symptoms and may exacerbate pre-existing asthma in children. Self-reported exposure to road traffic has been questioned as a reliable measurement of exposure to air pollutants. The aim of this study was to investigate whether there were specific effects of cars and trucks traffic on current asthma symptoms (i.e. wheezing) and cough or phlegm, and to examine the validity of self-reported traffic exposure.
The survey was conducted in 2002 in 12 centers in Northern, Center and Southern Italy, different in size, climate, latitude and level of urbanization. Standardized questionnaires filled in by parents were used to collect information on health outcomes and exposure to traffic among 33,632 6–7 and 13–14 years old children and adolescents. Three questions on traffic exposure were asked: the traffic in the zone of residence, the frequency of truck and of car traffic in the street of residence. The presence of a possible response bias for the self-reported traffic was evaluated using external validation (comparison with measurements of traffic flow in the city of Turin) and internal validations (matching by census block, in the cities of Turin, Milan and Rome).
Overall traffic density was weakly associated with asthma symptoms but there was a stronger association with cough or phlegm (high traffic density OR = 1.24; 95% CI: 1.04, 1.49). Car and truck traffic were independently associated with cough or phlegm. The results of the external validation did not support the existence of a reporting bias for the observed associations, for all the self-reported traffic indicators examined. The internal validations showed that the observed association between traffic density in the zone of residence and respiratory symptoms did not appear to be explained by an over reporting of traffic by parents of symptomatic subjects.
Children living in zones with intense traffic are at higher risk for respiratory effects. Since population characteristics are specific, the results of validation of studies on self-reported traffic exposure can not be generalized.