Is it traffic type, volume, or distance? Wheezing in infants living near truck and bus traffic
Received 15 March 2005; received in revised form 9 May 2005; accepted 10 May 2005. published online 16 June 2005.
Background
Previous studies of air pollution have not examined the association between exposure to varying types, distance, and amounts of traffic and wheezing in very young infants.
Objective
We sought to determine the relationship between types of traffic, traffic volume, and distance and wheezing among infants less than 1 year of age.
Methods
A geographic information system and a classification scheme were developed to categorize infants enrolled in the study as living near moving truck and bus traffic (highway >50 miles per hour, >1000 trucks daily, <400 m), stop-and-go truck and bus traffic (<50 miles per hour, <100 m), or unexposed and not residing near either. Symptom data were based on health questionnaires administered to parents when the infants were 6 months of age and monthly health diaries.
Results
Infants living very near (<100 m) stop-and-go bus and truck traffic had a significantly increased prevalence of wheezing (adjusted odds ratio, 2.50; 95% CI, 1.15-5.42) when compared with unexposed infants. The prevalence of wheezing among nonwhite infants was at least twice that of white infants, regardless of exposure. Infants living less than 400 m from a high volume of moving traffic, however, did not have an increased prevalence of wheezing.
Conclusion
These results suggest that the distance from and type of traffic exposures are more significant risk factors than traffic volume for wheezing in early infancy.
bDepartment of Internal Medicine, Division of Immunology, University of Cincinnati
Reprint requests: Patrick H. Ryan, MS, Department of Environmental Health, University of Cincinnati, Cincinnati, OH 45267-0056.
Supported by grants ES11170 and ES10957 from the National Institute of Environmental Health Sciences.
Disclosure of potential conflict of interest: S. A. Grinshpun has received grants–research support from the National Institute of Environmental Health Sciences. M. Villareal has consultant arrangements with Aventis, has stock or other equity ownership with Pfizer, and is on the speakers' bureaus for AstraZeneca, UCB Pharma, Pfizer, Aventis, and GlaxoSmithKline. There are not other potential conflicts to disclose.
ABSTRACT