Effect of exposure to traffic on lung development from 10 to 18 years of age: a cohort study.
BACKGROUND
Whether local exposure to major roadways adversely affects lung-function growth during the period of rapid lung development that takes place between 10 and 18 years of age is unknown. This study investigated the association between residential exposure to traffic and 8-year lung-function growth.


METHODS
In this prospective study, 3677 children (mean age 10 years [SD 0.44]) participated from 12 southern California communities that represent a wide range in regional air quality. Children were followed up for 8 years, with yearly lung-function measurements recorded. For each child, we identified several indicators of residential exposure to traffic from large roads. Regression analysis was used to establish whether 8-year growth in lung function was associated with local traffic exposure, and whether local traffic effects were independent of regional air quality.


RESULTS
Children who lived within 500 m of a freeway (motorway) had substantial deficits in 8-year growth of forced expiratory volume in 1 s (FEV(1), -81 mL, p=0.01 [95% CI -143 to -18]) and maximum midexpiratory flow rate (MMEF, -127 mL/s, p=0.03 [-243 to -11), compared with children who lived at least 1500 m from a freeway. Joint models showed that both local exposure to freeways and regional air pollution had detrimental, and independent, effects on lung-function growth. Pronounced deficits in attained lung function at age 18 years were recorded for those living within 500 m of a freeway, with mean percent-predicted 97.0% for FEV1 (p=0.013, relative to >1500 m [95% CI 94.6-99.4]) and 93.4% for MMEF (p=0.006 [95% CI 89.1-97.7]).


CONCLUSIONS
Local exposure to traffic on a freeway has adverse effects on children's lung development, which are independent of regional air quality, and which could result in important deficits in attained lung function in later life.
Gauderman
W James
WJ
Department of Preventive Medicine, University of Southern California, 1540 Alcazar Street, Suite 220, Los Angeles, CA 90033, USA. jimg@usc.edu
Vora
Hita
H
McConnell
Rob
R
Berhane
Kiros
K
Gilliland
Frank
F
Thomas
Duncan
D
Lurmann
Fred
F
Avol
Edward
E
Kunzli
Nino
N
Jerrett
Michael
M
Peters
John
J
D000293:Adolescent; D000393:Air Pollutants / Q000009:adverse effects*; D002140:California; D002648:Child; D015331:Cohort Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D016014:Linear Models; D008168:Lung / Q000187:drug effects / Q000254:growth & development*; D008297:Male; D008450:Maximal Midexpiratory Flow Rate; D012923:Social Class; D001335:Vehicle Emissions; D014797:Vital Capacity
D000393:Air Pollutants; D001335:Vehicle Emissions