ArticlesEffect of exposure to traffic on lung development from 10 to 18 years of age: a cohort study
Introduction
Both cross-sectional1, 2, 3, 4, 5, 6, 7, 8, 9 and longitudinal10, 11, 12, 13, 14, 15 studies have shown that lung function in children is adversely affected by exposure to urban, regional air pollution. Evidence has emerged that local exposure to traffic is related to adverse respiratory effects in children, including increased rates of asthma and other respiratory diseases.16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28 Cross-sectional studies in Europe have shown that deficits in lung function are related to residential exposure to traffic.27, 29, 30, 31, 32 However, does traffic exposure have an adverse effect on lung-function development in children? The answer to this question is important in view of the extent of traffic exposure in urban environments and the established relation between diminished lung function in adulthood and morbidity and mortality.33, 34, 35, 36, 37, 38, 39
We investigated the association between residential exposure to traffic and 8-year lung-function development on the basis of cohort data from the Children's Health Study. We also studied the joint effects of local traffic exposure and regional air quality on children's lung development.
Section snippets
Participants
The Children's Health Study recruited two cohorts of fourth-grade children (mean age 10 years [SD 0·44], one in 1993 (cohort 1, n=1718) and the other in 1996 (cohort 2, n=1959). All children were recruited from schools in 12 southern California communities as part of an investigation into the long-term effects of air pollution on children's respiratory health.7, 14, 40 A consistent protocol was used in all communities to identify schools, and all students targeted for study were invited to
Results
An average of 6·2 pulmonary function tests were done per child. There were equal proportions of male and female participants (webtable 1). Most children were of non-Hispanic white or Hispanic ethnic origin. 440 (12%) children lived within 500 m of a freeway, with most of these children residing in six of the 12 communities (webtable 2 and webfigure). Model-based estimates of pollution from a freeway were skewed toward either high or low values within most study communities.
8-year growth in FVC,
Discussion
This study shows that residential proximity to freeway traffic is associated with substantial deficits in lung-function development in children. 8-year increases in both FEV1 and MMEF were smaller for children who lived within 500 m of a freeway, than for those who lived at least 1500 m from a freeway. Freeway effects were seen in subsets of non-asthmatic and non-smoking participants, which is an indication that traffic exposure has adverse effects on otherwise healthy children. Deficits in
References (55)
Lung function and chronic exposure to air pollution: a cross-sectional analysis of NHANES II
Environ Res
(1989)- et al.
Association between lifetime ambient ozone exposure and pulmonary function in college freshmen—results of a pilot study
Environ Res
(1997) - et al.
Motor vehicle exhaust and chronic respiratory symptoms in children living near freeways
Environ Res
(1997) - et al.
Lung function, respiratory symptoms, and mortality: results from the Busselton Health Study
Ann Epidemiol
(1999) - et al.
Pulmonary function is a long-term predictor of mortality in the general population: 29-year follow-up of the Buffalo Health Study
Chest
(2000) - et al.
Ambient nitrogen dioxide and distance from a major highway
Sci Total Environ
(2003) - et al.
Characterization of a spatial gradient of nitrogen dioxide across a United States-Mexico border city during winter
Sci Total Environ
(2005) - et al.
Traffic-related differences in outdoor and indoor concentrations of particles and volatile organic compounds in Amsterdam
Atmos Environ
(2000) - et al.
Air pollution from traffic in city districtc near major motorways
Atmos Environ
(1998) - et al.
Particulate air pollutants and asthma. A paradigm for the role of oxidative stress in PM-induced adverse health effects
Clin Immunol
(2003)