Researchers at UCLA’s Fielding School of Public Health, led by Julia Heck, assistant researcher in the department of epidemiology and member of the Jonsson Comprehensive Cancer Center, have found a possible link between exposure to traffic-related air pollution and several childhood cancers.
These results were presented in an abstract today at the American Association for Cancer Research (AACR) Annual Meeting in Washington, DC.
In this, the first study on traffic air pollution and childhood cancers (other than leukemia, lymphomas and brain tumors), the UCLA researchers included 3,950 children in the California cancer registry who were born between 1998 and 2007 and could be linked to California birth certificates.
The researchers estimated local traffic exposure using California LINE Source Dispersion Modeling, version 4 (CALINE4). Exposure was estimated at each child’s home, during each trimester of their mother’s pregnancy with the child and their first year of life. The estimates encompassed information on gasoline and diesel vehicles within a 1,500-meter radius buffer, traffic volumes, roadway geometry, vehicle emission rates, and weather. Cancer risk was estimated using a statistical analysis called unconditional logistic regression.
Their findings showed that increases in exposure to traffic-related air pollution were associated with increases in childhood acute lymphoblastic leukemia (white blood cell cancer), germ-cell tumors (cancers of the testicles, ovaries, and other organs ), and retinoblastoma (eye cancer) particularly bilateral retinoblastoma (disease affecting both eyes). The pollution exposure estimates were highly correlated across pregnancy trimesters and the first year of life, meaning that no particular period stood out as a higher exposure time. This made it difficult for the scientists to determine if one period of exposure was more dangerous than any other.
“Much less is known about exposure to pollution and childhood cancer than adult cancers,” said Heck. “Our innovation in this study was looking at other more rare types of childhood cancer, such as retinoblastoma, and their possible connection to traffic-related air pollution.”
Because these are rare diseases, Heck cautions that these findings need to be replicated in further studies.
Source: UCLA’s Jonsson Comprehensive Cancer Center