Council on Environmental Health
Article Review

Prepared by: James R. Roberts, MD, MPH
October 2008

TITLE
Residential traffic and children’s respiratory health

AUTHORS
Kim, JJ; Huen K; Adams S; et al 

REFERENCE
Env Health Persp 2008;116(9):1274-9

STUDY DESIGN
Cross sectional

BACKGROUND
Outdoor air pollution is a known contributor to asthma complications.  Past studies have demonstrated an association with traffic patterns as markers of certain outdoor air pollutants. However, a high level of background ambient air pollution may interfere with or bias the effect from car exhaust. 

METHODS
This article looks at the location of children’s primary residence as a marker for effects from car exhaust related to traffic patterns using a geographic information system (GIS).  The setting was an area with good regional ambient air quality to minimize confounding. The authors used a sample of 1080 children and mapped their home address into the GIS.  They measured the distance of their homes to major roads. They also measured nitrogen oxides for a subsample of children to see how well they correlated with the traffic patterns and distance to roads. They used multivariate logistic regression to examine associations between each traffic measure and health outcome.

RESULTS
Children whose residences were in the highest quintile of exposure (using traffic metrics) had twice the adjusted odds ratio of having an asthma episode in the preceding 12 months compared to kids in the lowest quintile. Children living within 75 meters of a freeway or highway had the highest risks. Traffic metrics correlated well with the measured nitrogen oxides (NOx and NO). 

CONCLUSIONS
Residency proximity is associated with current asthma exacerbations and contributes to a growing body of evidence to this observation. The difference is that this study demonstrated good ambient air and included measured pollutants as well as the traffic metrics.

BOTTOM LINE
This is an interesting and well written article that adds to the compelling evidence of the relationship with ambient air and asthma.  GIS is a useful way to identify risks to children.  Traffic leads to higher ambient air pollutants, and can adversely affect health.

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