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Last Edited: 8/28/2009

Residential Exposure to Traffic in California and Childhood Cancer
Written: Jan 2004


Background:  Motor vehicle emissions are a major source of air pollution in California.  Past studies have suggested that traffic-related exposures may increase the risk of childhood cancer, particularly leukemia.

Methods:  From California's statewide, population-based cancer registry, we identified cancers diagnosed in children younger than five years of age between 1988 and 1997.  We matched these cases to California birth certificates.  For each case, we randomly selected two control birth certificates, matched on birth date and sex.  For each mother's residential address at time of her child's birth, we calculated road density by summing the length of all roads within a 500-foot radius of the residence.  Traffic density was based on road lengths and vehicle traffic counts for highways and major roads.

Results:  The distributions of road and traffic density values were very similar for the 4,369 cases and 8,730 matched controls.  For all cancer sites combined, the odds ratio (OR) for the highest road density exposure category, compared with the lowest, was 0.87 (95% confidence interval (CI) = 0.75-1.00).  For all sites combined and for leukemia, the ORs were also below 1.0 for the highest traffic density exposure category (0.92).  For central nervous system (CNS) tumors the OR was 1.22 (95% CI = 0.87-1.70).

Conclusions:  In a large study with good power, found no increased cancer risk among offspring of mothers living in high traffic density areas for all cancer sites or leukemia.

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Suggested Citation

  • Reynolds P, Von Behren J, Gunier RB, Goldberg DE, Hertz A .  Residential Exposure to Traffic in California and Childhood Cancer.  Epidemiology, 15(1):6-12, January 2004.