Air pollution from traffic at the residence of children with cancer

The hypothesis that exposure to traffic-related air pollution increases the risk of developing cancer during childhood was investigated. The authors e nrolled 1,989 children reported to the Danish Cancer Registry with a diagno sis of leukemia, tumor of the central nervous system, or malignant lymphoma during 1968-1991 and 5,506 control children selected at random from the en tire childhood population. The residential histories of the children were t raced from 9 months before birth until the time of diagnosis of the cases a nd a similar period for the controls. For each of the 18.440 identified add resses, information on traffic and the configuration of streets and buildin gs was collected. Average concentrations of benzene and nitrogen dioxide (i ndicators of traffic-related air pollution) were calculated for the relevan t period, and exposures to air pollution during pregnancy and during childh ood were calculated separately. The risks of leukemia, central nervous syst em tumors, and all selected cancers combined were not linked to exposure to benzene or nitrogen dioxide during either period. The risk of lymphomas in creased by 25% (p for trend = 0.06) and 51% (p for trend = 0.05) for a doub ling of the concentration of benzene and nitrogen dioxide, respectively, du ring the pregnancy. The association was restricted to Hodgkin's disease.