The risk of acute leukemia in children living close to heavily used roads has been the focus of a recent study by Inserm researchers from CRESS (Epidemiology and Biostatistics Sorbonne Paris Cité Research Centre, Inserm -- Paris Descartes University -- University of Paris 13 -- Paris Diderot University -- INRA). The results show that the incidence of new cases of myeloblastic leukemia (418 of 2,760 cases of leukemia) was 30 percent higher in children in the population whose home was within 150 meters of heavily used roads, and had a combined length of over 260 meters within this radius.
The research team considered all 2,760 cases of leukemia diagnosed in children under 15 years of age in metropolitan France over the 2002-2007 period. The results show that the incidence of new cases of myeloblastic leukemia (418 of 2,760 cases of leukemia) was 30 percent higher in children in the denser population area. In contrast, this association was not observed for the more common, lymphoblastic type of leukemia (2,275 cases). The researchers particularly studied the case of the Île-de-France region of Paris with the help of data modelled by Airparif, which is responsible for the monitoring of air quality in Ile-de-France. These results are published in the American Journal of Epidemiology and reported in Science Daily.
Cancer touches more than 1,700 children under 15 annually in France, which has a population of 11 million children. Surveillance has been provided by the French National Registry of Childhood Haematopoietic Malignancies since 1990, and by the French National Registry of Childhood Solid Tumors since 2000. Leukemias (blood cancers), with 470 new cases each year, are the most common childhood cancers, and are mainly acute lymphoblastic leukemias. "Myeloblastic" or "myeloid" leukemia, another type of leukemia, affects myeloid stem cells, which give rise to the red blood cells. Today, 5-year survival following childhood leukemia is more than 80 percent.
The GEOCAP program (GEOlocation Study of Paediatric CAncers) studies the role of environmental exposure in the occurrence of cancer in children under 15. One hypothesis is that there is an increased risk of leukemia in children living close to heavily used roads. The increased risk of myeloblastic leukemia for adults with occupational exposure to benzene is known.
The EPICEA (Epidemiology of Childhood and Adolescent Cancers) team, directed by Jacqueline Clavel, Inserm Research Director, at CRESS, has reported the results of a study on the incidence of leukemias in children living close to heavily used roads. It enabled the assessment of exposure level to one or more risk factors. All 2,760 cases of childhood leukemia diagnosed in metropolitan France between 2002 and 2007 were included in the study, and compared to a contemporary sample of 30,000 control children representative of the metropolitan population, and constituted in collaboration with the French National Institute of Statistics and Economic Studies (INSEE).
According to Jacqueline Clavel, Inserm Research Director, "The frequency of myeloblastic type leukemias was 30% higher in children living within a 150 m radius of heavily used roads, and where the combined length of road sections within this radius exceeded 260 m." There was no association between acute lymphoblastic leukemias -- the most common -- and the atmospheric concentration of nitrogen dioxide, distance or combined length of heavily used roads in the vicinity of dwellings.
The researchers emphasized the Île-de-France region of Paris, the most urbanized region. They observed that the risk of childhood acute myeloblastic leukemia was double in Île-de-France children whose residences were the most exposed to traffic.