TRAFFIC DENSITY AS A RISK FACTOR FOR CHILDHOOD ASTHMA

Abstract

ISEE-129 Abstract: The object of this study was to determine whether children who live in high traffic areas have a greater risk of developing asthma. The parents of kindergarten and first grade children in thirteen schools were surveyed for asthma symptoms in their child, doctor’s diagnosis of asthma, household risk factors, and history of parental asthma. The household location was placed on a Geographic Information Systems (GIS) map and a buffer of 100 meters (one city block) and 300 meters was drawn around each location. Two traffic exposure variables were created for each child by measuring the length of all segments of roadways falling within the two buffers and multiplying by the average daily traffic count on that roadway at that location. These calculated exposure variables were categorized into low, medium and high traffic density exposure based on percentiles of the distribution. Over 1100 surveys were returned. Overall rate of doctor diagnosed asthma for kindergarten and first-grade children was 11%. Traffic exposure was calculated for the 100-meter buffer (traffic density within one city block) and the 300-meter buffer (traffic density within 3 blocks of the residence). Multiple logistic regressions and spatial regression were done with doctor-diagnosed asthma as the dependent variable and traffic exposure as an independent variable. Other independent variables included parental asthma, smoker in the house, family income, and gender. The results show that the adjusted odds ratio for children being diagnosed with asthma was 2.38 (1.19, 4.76) for high traffic within 100 meters of residence and 2.74 (1.35, 5.56) for high traffic within 300 meters of residence. As it is unlikely that parents of children with asthma preferentially move to areas of high traffic density, this study indicates that living close to high traffic areas may be a risk factor for receiving a diagnosis of asthma in early childhood. Further studies are needed to confirm this hypothesis.