Examining associations between childhood asthma and traffic flow using a geographic information system.

TLDR

Repeated exposure to particulate matter and other air pollutants from traffic exhaust may aggravate asthmatic symptoms in individuals already diagnosed with asthma. The study used GIS and routine data to investigate whether living near busy roads is linked to childhood asthma in a low‑income San Diego County population. Researchers mapped 5,996 asthmatic children’s homes and 2,284 control homes, linked each to traffic counts within a 550‑ft buffer, and analyzed whether asthma visit frequency correlated with traffic flow. No significant association was found between traffic exposure and asthma diagnosis, but children living near high‑traffic streets were more likely to have multiple medical visits, indicating traffic flow may increase repeated care for asthmatic children.

Abstract

Using geographic information systems (GIS) and routinely collected data, we explored whether childhood residence near busy roads was associated with asthma in a low-income population in San Diego County, California. We examined the locations of residences of 5,996 children [less than/equal to] 14 years of age who were diagnosed with asthma in 1993 and compared them to a random control series of nonrespiratory diagnoses (n = 2,284). Locations of the children's residences were linked to traffic count data at streets within 550 ft. We also examined the number of medical care visits in 1993 for children with asthma to determine if the number of visits was related to traffic flow. Analysis of the distribution of cases and controls by quintiles and by the 90th, 95th, and 99th percentiles of traffic flow at the highest traffic street, nearest street, and total of all streets within a 550-ft buffer region did not show any significantly elevated odds ratios. However, among cases, those residing near high traffic flows (measured at the nearest street) were more likely than those residing near lower traffic flows to have two or more medical care visits for asthma than to have only one visit for asthma during the year. The results of this exploratory study suggest that higher traffic flows may be related to an increase in repeated medical visits for asthmatic children. Repeated exposure to particulate matter and other air pollutants from traffic exhaust may aggravate asthmatic symptoms in individuals already diagnosed with asthma.